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Quickie Questions - Earth - Other

Date Answered Questioner (age, location) Question Answer
May 4, 2011rin(romania)When uranium atoms split the neutrons clashing eachother release the energy to make the atomic bomb, but how come so much energy from such a small piece of uranium?This is a perfect example of Einstein's equation E = mc2. Although the excess mass m of the un-split uranium is small, the factor c is so large that the energy release E is also large. The physical reason is that uranium is less stable than what it splits into.
March 20, 2011frankI don't know what the "2012 riddle" is. I read that some people believe there will be a global transformation or catastrophe in 2012. Like many predictions, that one may or may not be true, but I find no scientific basis for believing it. Science is concerned with predictions that can be tested by experiment or observation.
May 10, 2010teresia (kenya)is it true that the earth was formed by a whirling mas of gas?Your question is answered in detail in our web page Solar System Formation.
May 10, 2010Rosalie (Washington)How did the continents split up?This figure shows the continents united in a super continente called Pangea. The surface of our planet is transformed over long amounts of time, by the process of plate tectonics.
May 3, 2010Tumelo (South Africa)which fault is not one of the three types of boundaries between lithospheric plates?Plate boundaries are found at the edge of the lithospheric plates and are of three types, convergent, divergent and conservative. However, not all plate boundaries are easily defined. One example would be the Mediterranean-Alpine boundary, which involves two major plates and several micro plates.
May 3, 2010Huma (South Africa)Where does the majority of earthquakes and volcanoes occurs?Most earthquakes happen at or near the boundaries between Earth’s tectonic plates because that’s where there is usually a large concentration of faults. Some faults crack through the Earth because of the stress and strain of the moving plates. Other, large faults are the boundary between plates, such as the San Andreas Fault on the North American west coast. See our web page Where Do Earthquakes Happen? for more information.
April 27, 2010jahnavi.s (india)is 2012 the movie is true the earth is going to blast on 2012 can u pl answer this ouestion?There is no scientific fact to support such a catastrophe. Our planet has many more centuries to go.
April 23, 2010julia (finland)how and why do day lengths change across europe with latitude and season?Seasons and the lenght of the day are related with the tilt of our planet axis. It is known that the length of a day varies throughout the year, and depends upon latitude. This variation is caused by the tilt of the Earth's axis of rotation with respect to the vertical. At solstices (June and December 20-22), one of the poles is tilted toward the sun. The hemisphere that is tilted toward the sun has days ranging in duration from just over 12 hours around the equator to 24 hours in the polar circle, while the opposite hemisphere has days ranging in duration from just under 12 hours around the equator to zero in the polar circle. At the equinox (about September 22-23) the poles are neither tilted toward nor away from the sun, and the duration of a day is generally about 12 hours all over the earth.
April 20, 2010Jackson (Va Beach)What is acid snow and what is it's scientific name?Acid snow, as acid rain is a form of precipitation unusually acidic. It can have harmful effects on plants, aquatic animals, and infrastructure.
April 2, 2010aiman (pakistan)what is ridge made ofA ridge is a continuous elevational crest for some distance. There are several types of ridges, one of them is the oceanic spreading ridge, in tectonic spreading zones such as at the Mid-Atlantic Ridge, where the volcanic activity forming new plate boundary forms volcanic ridges at the spreading zone.
April 2, 2010aiman (pakistan)name the plates that lies on each side of the ridgeThe main force that shapes our planet’s surface over long amounts of time is the movement of Earth's outer layer by the process of plate tectonics.
April 1, 2010emily (north carolina)what percent of raditation is lost before reaching earths surface?Less than 20 percent of the solar radiation reaching Earth is absorbed by atmospheric gases and clouds, 50% is absorbed by Earth's surface--mostly the ocean, and 31% is reflected back to space.
March 30, 2010Sam (USA)What is the rotational relationship between the earth and the sun that causes day and night?The main reason for the day-night sequence is the rotation of our planet on its own axis. It takes near 24 hours to complete a full rotation, and during this period, the planet shows different parts to the Sun. The side of the planets facing the Sun will be day, the opposite, night.
March 29, 2010hanah (california USA)How come Earth has oxygen and other planets do not?The Earth receives most of its oxygen from photosynthetic activity, the process by which plants convert water, carbon dioxide, and solar energy into sugars and oxygen. There are no known plants on other planets, therefore, no production of oxygen by photosynthesis.
March 26, 2010Elaine (PHILIPPINES)WHY DO MOST EARTHQUAKES OCCUR ALONG A FAULT LINE?When the giant blocks of rock that make up the Earth's crust are moved by plate tectonics, they are bound to bump into each other sometimes. These blocks of rock come in contact at faults. Sometimes they slide smoothly past each other. Other times the rocks get stuck - the rough surfaces of rock snag and they can't move along the fault. That might lead to an earthquake. MOre information on our web page Why Do Earthquakes Happen?.
March 25, 2010yul are the stories about that the world will end in 12/21/2012 true?This article should answer your question. Let me quote the last three paragraphs: "But scholars doubt the ancient Maya extrapolated great meaning from anticipating the alignment — if they were even aware of what the configuration would be. Astronomers generally agree that "it would be impossible the Maya themselves would have known that," says Susan Milbrath, a Maya archaeoastronomer and a curator at the Florida Museum of Natural History. What's more, she says, "we have no record or knowledge that they would think the world would come to an end at that point." University of Florida anthropologist Susan Gillespie says the 2012 phenomenon comes "from media and from other people making use of the Maya past to fulfill agendas that are really their own."
March 24, 2010damien (america ,texas)WHAT IS THE SCIENTIFIC FACT ON THE WORLD ENDINGI would say that the most likely way for our planet to die is linked with the Sun life. As has been pointed before, a star with a mass similar to our Sun and in the last phase of its life is a red giant. At this point, the Sun will have expanded to cover all the interior planets, including the Earth. But before that, in about 1.1 Gyr (1 100 000 000 years) from today) the Sun will be 10% brighter and this extra solar energy will cause the Earth's atmosphere to dry out. Under such conditions, surface life on Earth will probably be exterminated.
March 23, 2010gensis (bronx)in what layer does the water cycle happen?Biosphere, atmosphere, cryosphere, and hidrosphere are all included in the water cycle.
March 19, 2010katelyn (usa)what were the major things that happend in the 79ad erupion of mount vesuvius?The most notable thing that happened was the complete destruction of Pompeii. On August 24, 79 Mount Vesuvius literally blew its top, spewing tons of molten ash, pumice and sulfuric gas miles into the atmosphere. The Roman cities of Pompeii, Herculaneum and Stabiae were covered by tons of falling debris, which filled the streets until nothing remained to be seen. The cities remained buried and undiscovered for almost 1700 years until excavation began in 1748, and still continue today.
March 5, 2010Rishib (India)Is ozone a green house gas?Yes, the main greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone.
March 3, 2010Jane (Massachucetts)How was the Pacific Ring of Fire formed?The Ring of Fire was formed around the Pacific Plate and other major tectonic plates. The Pacific Plate is sliding underneath other plates (subduction). The tremendous amount of energy created by the intereaction among these plates melt rock into magma, which rises to the surface as lava and forms volcanoes.
March 3, 2010geraldine (philippines)when volcano occurVolcanoes occur at the edges of the tectonic plates that form the Earth crust. Volcanoes can also occur in the middle of plates, in hotspots.
March 3, 2010Lojine (Canada)What is the difference between ocean and dessert habitat?Our pages The Desert Biome and The Ocean Biome describe in detail each of them. There you will find their characteristics and main differences.
February 23, 2010Fred (U.S.A.)SE Hudson Bay has a curious arc with Blecher Is. in a potential circle extended beyond that. Is this feature an impact site similar to one near Gagnon, Quebec, but much larger with attendant crustal rebound?Your question is better answered by an especialist. See the article Non-Impact Sites for the answer to your question.
February 17, 2010Luure (Ghana)what are the importance of climate change on crop, animal and water resourcesA change on weather and climate patterns will produce drastic changes on many different aspects of our lives. Our web page Climate and Global Change News lists many links to other pages where these changes are discussed.
February 16, 2010kenet (philippines)What are the climate of the past?Although there weren’t any people on Earth to describe what climate was like, the Earth kept records of past climates in special ways. Sediments and fossils deposited millions of years ago provide a record of ancient environments. Our web page Climates of the Past describes the different methods to study the paleoclimates, and offer links to more information about how climate has changed in the past.
February 11, 2010Jeff (Colorado)We were discussing this in class and a good answer really did not come out about the dayside of the ionosphere.
What effect would a major solar flare, which emits a large amount of UV and Z-ray radiation, have on the dayside ionosphere?
Such a particular topic is beyond the reach of this section, but as it happens the ionosphere is my field of research. So, I can’t let it pass. This has been a topic of research for some time. Recent developments have shown that flare EUV photons can increase the total electron content of the subsolar ionosphere by up to 30% in very short times. Flare-related particles that precipitate into the ionosphere cause rapid increases in the polar atmospheric ionization, disruption of transpolar communication, and cause ozone destruction. A recent and good review of the current state of this topic appears in: Tsurutani, B. T., O.P. Verkhoglyadova, A.J. Mannucci, G.S. Lakhina, G. Li, G.P. Zank (2009) A brief review of “solar flare effects” on the ionosphere, Radio Science, 44 (A5). doi:10.1029/2008RS004029
February 9, 2010susana (jamaica)ways climate change affect tourists internationallyThe answer to your question requires a serious investigation that escapes the reaches of this section, but I can think, from the top of my head, os a couple of ways in whch turism could be affected. For example, coral barriers are big magnets for scuba divers and snorkelers, a big turism atraction, but with the warming of the oceans the corals are affected and can even die. Costal zones could be also affected with the increase of the sea level, with beaches, low lands, etc., in danger of dissapearing.
February 5, 2010destiny (missouri)what are sedimentary rocks made out of .Many sedimentary rocks are made from the broken bits of other rocks. These are called clastic sedimentary rocks. The broken bits of rocks are called sediment. Sediment is the sand you find at the beach, the mud in a lake bottom, the pebbles in a river, and even the dust on furniture. The sediment may, in time, form a rock if the little pieces become cemented together. There are other types of sedimentary rocks whose particles do not come from broken rock fragments. Chemical sedimentary rocks are made of mineral crystals such as halite and gypsum formed by chemical processes. The sediment particles of organic sedimentary rocks are the remains of living things such as clamshells, plankton skeletons, dinosaur bones, and plants. Visit our webpage What Is a Sedimentary Rock?, and the links therein, for more information.
February 5, 2010jada (tx)rocks and sediments are part of the earth's what?The Earth's crust is composed of a great variety of igneous, metamorphic, and sedimentary rocks.
February 3, 2010Emiliano (Wisconsin)were are petroleum and natural gas locatedThis map shows oil proven reserves, and this one shows the exporters of natural gas, which also own the main reserves.
February 3, 2010hussein (tanzania)How can climate change effect the earths atmosphere?Uncontrolled warming of the atmosphere could be the cause for climate global changes. In turn, if there is an increase of the global temperature, the atmosphere would expand.
February 1, 2010sunaina (india)what would happen to earth's temperature if its atmosphere is removed.A planet with no atmosphere will have extreme changes of temperature, instead of the more uniform temperature we enjoy in our planet. The day side of the planet would be scorching hot, while the night side would be freezing.
January 27, 2010july (philippines)what is the size of each kinds of volcano?Cinder cones reach about 1,000 feet above their surroundings while composite volcanoes can grow up to several thousand feet. Shield volcanoes are large, up to several tens of thousands feet. Lava domes are relatively small because they typically copllapse and has to rebuild itself.
January 27, 2010james (canada)Is it possible to say the mantle is perpetually cooling, and the crust and/or surface is either cooling or warming depending on changes in the atmosphere?It could be said ina very general sense. More than "depending on changes in the atmosphere", the crust superficial temperature is a function of the latitude and seasons.
January 18, 2010Kee (Singapore)How does car smoke affect animals?Carbon dioxide is one of the main component of car exhaust, it is also one of the most important greenhouse gases, responsible of the Global Warming effect.
January 18, 2010DAVID If we on this planet, are using up an amazing amount of fossil fuels, especially COAL, at the rate we are, will the planet not become much lighter In weight and will this not effect the functioning of the planet earth ?Close to a trillion barrels of oil have been extracted from the ground since drilling began, an insignificant amount when compared with the Earth's total mass (5.98 x 1024 kilograms or 6.5 x 1021 tons). The crust, where all the oil is found, accounts for less than half a per cent of the total mass of the Earth.
January 15, 2010Jalil (Madison il)What is the earth most earthquakes?Earthquakes happen when rock moves suddenly. Usually this happens along cracks in Earth’s crust called faults. There are many faults at the breaks between Earth’s tectonic plates. Our web page Where Do Earthquakes Happen? includes an animation that will help you to visualize where are this faults.
January 12, 2010Anna (California)What is the time of sunset for the longest and shortest days of the year in San Francisco?The shortest day corresponds to winter solstic, December 21 in 2010. The longest is the Summer solstice, June 21, 2010. You can obtain the times of sunrise, sunset, moonrise, moonset,etc. for any day and location here.
January 11, 2010Shiana (MICHGAN)Is there any more sites for biomes??????? Pales respond!Our web page Biomes and Ecosystems and the links therein cover lots of detail about biomes.
January 8, 2010MICAH (WASHINGTON)If the Mesosphere eats meteors how do rockets, and satelites get threw the Atmosphere?Not all objects going through the atmosphere burn out. It depends on several factors, size, speed and composition (what is the object made of) among them.
January 7, 2010Lauryn (Britain)The Earth tilts on it's own axis at 23.5 degree's. The Tropics of Cancer and Capricorn are 23.5 degree's from the equater. Is there a connection?The tropics include all the areas on The Earth where the sun reaches a point directly overhead and a point directly underneath at least once during the solar year. This only happens between the Tropics of Cancer and Capricorn. Outside this band of latitud, AND DUE TO THE TILT OF EARTH'S AXIS, the sun is never directly overhead or directly underneath.
January 7, 2010arundhati (trivandrum,india)why the planets are tilted towards a certain side ?The most widely accepted theory is that during the formation of the Solar System objects of significant masses, probably protoplanets, collided with them, causing the tilt of the axis.
January 6, 2010Victoria (Michigan)What is the average winter temperature in North America?In the contiguous United States, the average winter temperature for the 20th century was 33.4°F (0.7°C).
January 5, 2010John (Wisconsin /USA)2012 is really getting a lot of attention. I've heard that on 12\21\2012 the earth and the sun will line up directly with the center of the milky way galaxy. Will this event possibly change the rotation or the axis of the earth?There are no planetary alignments in the next few decades, Earth will not cross the galactic plane in 2012, and even if these alignments were to occur, their effects on the Earth would be negligible. Each December the Earth and sun align with the approximate center of the Milky Way Galaxy but that is an annual event of no consequence. Much more about the 2012 hype on this NASA page.
January 4, 2010Melissa (Trinidad)how does water pollution affect the coral reefThere are different ways in which pollution affects coral reefs. For example, runoff from land "often carries large quantities of sediment from land-clearing, high levels of nutrients from agricultural areas and sewage outflows, and pollutants such as petroleum products and pesticides. These land-based sources of pollution threaten coral reef health." (from NOAA website). But there is also the effect of Air Pollution on reefs: The carbon dioxide air pollution, when absorbed by ocean waters, causes “ocean acidification” which adversely affects the health of coral reef systems.
December 30, 2009alyssa (wyoming, United states)If a sedimentary rock can become any other type of rock does it's chemical compound change when it does so?Metamorphosis is the process that could change a sedimentary rock in a different kind of rock. Metasomatism is the change in the chemical composition of a rock that often occurs during the processes of metamorphism. Metamorphic rocks generally contain many elements absent from the original rock, and lack some that originally were present.
December 28, 2009alyssa (ca/usa)If we have only drilled 7miles down. How do we know how the earth's layers are made up. Lithosphere,asthenosphere,mantle,inner core and outer core and such.

Thank you.
There are multiple methods to study our plane interior, among them are the study of seismic wave behavior and the Earth's gravitational field. offers some details about the use of seismic wave to study the earth's interior.
December 23, 2009Larissa (0regon, usa)Why isn't the rock buried 25 meters below the ground considered part of the biosphere?The actual limits of the biosphere (defined en 1875 as "The place on earth's surface where life dwells") are difficult to define. There are birds that fly at altitudes of more than 8 000 meters (Bar-headed Geese migrate at altitudes of at least 8 300 meters!!), and fish that live at more tan 8 000 meters deep. Microbes have also been found living deep under the Earth's terrestrial surface. So, is a rock buried 25 meters part of the biosphere? I am sure there is not a unique answer to that!
December 22, 2009Douglas (United States/CA)why dose our planet support lifeOur planet is in a privileged position inside the Solar Sytem, not too close and not too far from the Sun, for lots of water. For more about this topic, visit our web page The Goldilocks Theory.
December 21, 2009anne-maree (queensland, AUSTRALIA)With all the disasters happening in the world now, do you believe the world is nearly at it's end?While I do believe that we, the Human race, have been abusing our planet, I don't believe anything about the disastrous predictions for 2012. There is not a single scientific reason for that.
December 17, 2009miranda (texas)how many megatons of carbon are released into the atmosphere as fossil fuels are burned each year?5.5 billions of tons of carbon are due to fossil fuel emissions. See this chart for more information.
December 17, 2009Gabby (kentucky)can you find the rock layers of the mesozoic in Kentucky?Extracted from The Paleontology Portal: The retreat of the extensive shallow seas of the Paleozoic left much of Kentucky exposed during the late Paleozoic (Permian) and Mesozoic; however, fossils from a few Permian rocks brought up in drill cores indicate that the shallow sea persisted in the far western part of the state. The Mesozoic is represented only by a small area of Cretaceous rock in the far western Jackson Purchase area. These rocks are mainly nearshore marine gravels and sands, deposited from rivers flowing from the north and east. Few fossils are known from this time.
December 16, 2009karen (phillipines)what are the effects f climate change?For information on this topic visit our web pages: Effects of Climate Change Today limate and Global Change News For more information, please, visit the links that appear here.
October 27, 2009Shamsudheen (India)Is there any change in the proportion of land and sea or land and water in the history of earth?Yes, in the very beginning, during the cooling of our primitive planet, water vapor began to escape fromthe thin crust on Earth's surface and condense in the Earth's early atmosphere. Then masive rains started, until the earth was flooded with water, forming the seas.
October 27, 2009KONNER (MN)WHAT ARE SOME GRASSLAND ABIOTIC FACTORSTemperature, precipitation, wind, and humidity are abiotic factors for grasslands.
October 27, 2009Jill (United States)How did the earth come to have an axial tilt?It is widely accpted among scientists that Earths axis was tilted very early in the evolution of our planet, when a object around the size of Mars struck Earth.
October 19, 2009jeany (ireland)how fossil fuels gas emission affect the weathering process of rocks and minerals?I can see two direct ways, through particulates and through acid rain.
October 19, 2009KINDLE (GEORGIA)WHAT IS A TRENCH AND A RIDGE?Trench can be defined as a long steep-sided depression in the surface or ocean floor. A ridge is a geological feature that features a continuous elevational crest for some distance.
October 19, 2009syrena (united states)what is the cause if a vernal equinexOn an equinox (which occurs around March and September 21), neither half of the Earth points directly towards the Sun. In fact, the Sun is at the equator, so both halves of the Earth are getting about the same amount of sunlight. See our web pag The Vernal and Autumnal Equinoxes for more information.
October 19, 2009jasmine (Ohio, USA)What is the actual Diameter at equator in kilometersEarth's diameter measured across the equatorial plane is 12 756.28 km.
October 19, 2009janhavi (India)My teacher tells us that Grenland is called so as it is full of meadows and the Earth was much warmer in the past and if it is true Greenland should be much warmer as a result of Global Warming ?It is already warmer. See this National Geographic article for more information.
October 19, 2009 what would happen to plant and animal life if the earth did not tilt on it (age , )Too many assumptions have to be made to answer your question. But there is something for sure, without Earth's axis tilt there wouldn't be seasons in our planet. This will surely affect the distribution of life in our planet!
October 16, 2009dan (marietta Ga)why do all parts of earth not have light at the same timeOur planet is a big sphere, and at any moment face the Sun with just half of the world.
October 16, 2009andrew (Pennsylvania)What is a natural phenomenon that occurs in the mesosphere?A well known one is the Polar Mesospheric Clouds, also known as Noctilucent Clouds, first observed above polar regions in 1885. See some pictures here.
October 16, 2009Maurice (WALES)how is the earth older than the other planets
and the sun because earth should travel round
the sun?
The Sun, Earth, and the rest of the planets were born out of he solar nebula and are all of the same age, thought to be about 4.5 billion years.
October 16, 2009salina (indiana, usa)whats the chance of a world wode tsunami covering all land mass?I don't think that there is the possibility of a global tsunami covering all land masses. The amount of energy needed for such event is enormous! This NOAA's web page offers several good animation of what scientists consider to be global tsunamis.
October 16, 2009mushtaq (pakistan)how magma chamber produced two types of magma?There are three types of magma: Basaltic magma -- SiO2 45-55 wt%, high in Fe, Mg, Ca, low in K, Na Andesitic magma -- SiO2 55-65 wt%, intermediate. in Fe, Mg, Ca, Na, K Rhyolitic magma -- SiO2 65-75%, low in Fe, Mg, Ca, high in K, Na This detailed explanaton of the processes involved in magma differentiation is offerd by Prof. Stephen A. Nelson of Tulane University.
October 13, 2009gina (new jersey)May I ahve information on Ice?Are you asking about ice as a state of matter? Maybe the polar caps of our planet? See these links to several of our pages for related information: The Cryosphere The Cryosphere and Global Climate Change The Martian Cryosphere Snow Resources for Teaching About the Poles and the Cryosphere What Controls the Climate?
October 9, 2009Amareah (North Carolina)How much damge did Hurricnae Katrina do?Hurricane Katrina: This August 2005 storm was the most destructive and costly natural disaster in U.S. history. It produced damage estimated at $75 billion in the New Orleans area and along the Mississippi coast. Katrina was responsible for approximately 1,200 reported deaths, including about 1,000 in Louisiana, 200 in Mississippi, and seven in southern Florida. Extracted from FEMA for Kids.
October 8, 2009Mark (Minnesota)Will the Coriolis effect cause the Earth’s molten core to reverse direction after we pass through the Galactic Equator approximately soon after 2012 Dec 21, or will this cause the axis to shift?
And
Will the Earth’s magnetic shield collapse when we enter the Galactic equator, allowing solar particles and cosmic energies to reach the surface of the Earth?
I don't see a particular reason to relate the Coriolis Effect and the motions of Earth's core with the Galactic Equator, but this is not my field of work!
October 6, 2009Daniel (NSW, Australia)How thick is a tsunami?I am not sure about your question. If you want to know how high are the tsunami waves, they can go from a couple of feet high up to hundreds of feet high (a 500 m wave was calculated for the Lituya Bay Tsunami of 1958).
October 2, 2009ru (america)IN HOW MANY YEARS WILL THE BLACK HOLE DESTROY THE EARTH.A star with a mass similar to that of our Sun and in the last phase of its life is a red giant. At this point, the Sun will have expanded to cover all the interior planets, including the Earth. But before that, in about 1.1 Gyr (1 100 000 000 years) from today) the Sun will be 10% brighter and this extra solar energy will cause the Earth's atmosphere to dry out. Under such conditions, surface life on Earth will probably be exterminated. So, it will not be a black hole the culprit of Earth ill fate, it will be our old friend the Sun.
October 2, 2009Chloe (South Australia)What happens when a Meteorite collides with Earth? What is it called?It depends on several things, mainly mass and energy (of which mass is a factor). There are some impact craters on our planet (see our web pageImpact Craters on Earth) and there is also the theory of the formation of the moon as a result of a huge impact with our planet. This theory is known as Giant Impact, and asserts that the proto-Earth was hit by a Mars-sized body and Moon formed from the debris.
September 30, 2009flubbyhead (usa)Is my magnet mis-labeled, or is the North pole mis-labeled?Because the magnetic poles of our planet are inverted respect to the geographical poles, the north side of your magnet will point to the north geographical pole, which corresponds to the south magnetic pole.
September 30, 2009Gale Teschendorf (IL)Do solar panels add to global warming?
Since they are very dark colored it appears that they would trap heat not unlike CO2.
Interesting question and I don't know the answer. Just speculating, since solar panels transform the solar energy into electricity, the amount of energy reflected back should be minimum (although there is always some). I would expect that with time, the efficiency coefficient of the solar panels would increase, and more energy would be converted in to electricity. The other factor I see right now is that the total surface of solar panels around the world is not considerable when compared against other sources of global warming, and let’s hope it stays like that!
September 28, 2009Ajay (India)In which Country to see Seven (7) Sun at a timeThere is only one Sun in our Solar System. But, of course, all the stars are suns, so from any place on Earth we always see more than one sun!
September 28, 2009ayesha (Pakistan)wat is the reason of movement of sun & other stars in the sky?wat is the origin of their movement?We see them bacause because our own motions. This is called "apparent movement" of the stars, Sun, etc. As we spin around the planet axis, we see the Sun, moon, stars, etc. moving accros the sky, but it is really us who are moving with the planet.
September 25, 2009sage (texas united states)why is tornado alley most likely to get tornadoes?Thunderstorms needs warm, humid air. And the rotating thunderstorms (that produce tornadoes) need low-level winds that shift direction and grow stronger just above the ground. These factors are better found in the Central USA, the plains between the Appalachians and the Rocky Mountains.
September 25, 2009miguelle (seychelles)how the earth turns in rotation to day time and night timeBeacuse Earth rotation, different sides of the Earth are facing the Sun at different times. The sides facing the Sun are on day time, the opposite side, which is under the Earth's own shadow, are on night time.
September 17, 2009Therese (Belgium)Why do you think CO2 is portrayed in the media as the only major greenhouse gas?The main greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. From the human-produced ones, CO2 is the most important.
September 16, 2009Lachie (Australia)Could you please explain how the carbon we breathe out today may have been part of the body of a dinosaur 100 million years ago.Because the carbon continuously moves through a cycle know as The Carbon Cycle. This figure is also very informative.
September 16, 2009umamaheswari (tamilnadu)what happen when earth is not tilted?One of the main effects would be that we wouldn't have seasons in our planet. Please, visit our page Earth's Tilt Is the Reason for the Seasons! for more nformation.
September 14, 2009LarryThere is no scientific evidence of earth motion, other than earthquakes. If there is no motion, why the earth tilt?You are touching two unrelated issues. The prevalent theory about the tilt of our planet axis describes the cause as the impact of a large object against Earth, possibly creating the Moon out of a large chunk of the planet. On the other hand, there are more evidences of the plate tectonic. The Mid-Ocean Spreading Ridge, and the Pacific Rim of Fire are two of the better known.
August 24, 2009Janis (New Zealand)How did the Earth come to be?Scientists believe that the solar system (Sun, planets, comets, etc.) was formed when a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star (called a supernova). This explosion made waves in space which squeezed the cloud of gas and dust. Squeezing made the cloud start to collapse, as gravity pulled the gas and dust together, forming a solar nebula. Just like a dancer that spins faster as she pulls in her arms, the cloud began to spin as it collapsed. Eventually, the cloud grew hotter and denser in the center, with a disk of gas and dust surrounding it that was hot in the center but cool at the edges. As the disk got thinner and thinner, particles began to stick together and form clumps. Some clumps got bigger, as particles and small clumps stuck to them, eventually forming planets or moons . Near the center of the cloud, where planets like Earth formed, only rocky material could stand the great heat. Icy matter settled in the outer regions of the disk along with rocky material, where the giant planets like Jupiter formed. As the cloud continued to fall in, the center eventually got so hot that it became a star, the Sun, and blew most of the gas and dust of the new solar system with a strong stellar wind. By studying meteorites, which are thought to be left over from this early phase of the solar system, scientists have found that the solar system is about 4,600 million years old!
August 21, 2009cya (india)what is the secret behind the bermuda triangle?sir,please give the answer to this question..

is it the alien forces,or cyclones,or are there flying landmasses or there are hot balls of gases flying in the air?
The Bermuda Triangle phenomenon, when scientifically observed, shows a very different side. This article discusses the topic.
August 18, 2009nicky (NY)what direction do winds generally blow across the U.S.??The prevailing winds, known as westerlies, blow to the northeast. Please, see this page, especially the last diagram.
August 17, 2009Butch (North Carolina, USA)Why is it that on earth the hottest spots seem to be the lowest and the coldest seem to be the highest? Looks like since the mountains are closer to the sun they would be warmer. Also as the heat from the sun travels through space to earth why doesn't the space get warmer? Is there some heat lost in space as it travels to the earth?Sunlight streams down from space through the atmosphere, striking the ground or ocean beneath. The sunlight heats the surface, and that surface radiates the heat into the adjacent atmosphere. This is the reason the troposphere, the lowest layer of Earth's atmosphere, is heated from below. The troposphere is warmest at the bottom near Earth's surface.
August 10, 2009aparna (germany)Whow r astroids ,comets and meteors formed
Whow is mars red
A widely accepted theory for the formation of the Sun (and planets, comets, etc) is that solar systems are formed when a cloud of gas and dust in space is disturbed, maybe by the explosion of a nearby star (called a supernova). This explosion make waves in space which squeeze the cloud of gas and dust. Squeezing made the cloud start to collapse, as gravity pulled the gas and dust together, forming a solar nebula.
August 7, 2009Genesis ( Georgia)When do think the Earth will die? WIll be off the earth and on another plant? or will we die along with earth?A star with a mass similar to that of our Sun and in the last phase of its life is a red giant. At this point, the Sun will have expanded to cover all the interior planets, including the Earth. But before that, in about 1.1 Gyr (1 100 000 000 years) from today) the Sun will be 10% brighter and this extra solar energy will cause the Earth's atmosphere to dry out. Under such conditions, surface life on Earth will probably be exterminated.
August 7, 2009Tintswalo (South Africa)Can you please tell me more on intrusive and extrusive volcanoes please.This is a common mistake. Volcanoes are extrusive because their lavas are extruded onto the surface of the Earth (either on the continents or on the seafloors). For this reason, there is no definition for intrusive volcanoes.
July 27, 2009TANKISO (SOUTH AFRICA)THE EARTH IS ROUND IN SHAPE,BUT BY THE OBSERVATION OF THE PEOPLE TO ITS OWN SURFACE SEEMS TO BE FLAT SURFACE WHY?Essentially this phenomenon is due to the fact that our planet is extremely large (a radius of about 12,756 km) respect to a human being (average height about 1.6 m), so we are able to see just a very small part of the surface of the planet, which seems flat in our eyes.
July 27, 2009TANKISO (SOUTH AFRICA)IF THE INNER PART OF THE EARTH DO HAVE HIGHER TEMPERATURE AND ALSO THE SUN GIVE OUT THE HEAT TO ITS SORROUDINGS PLANET WHY DO WE AS HUMAN IN THE PLANET EARTH GET BURN OUT, BECAUSE OF THE TWO COMBINATION OF HEAT?Our planet is at the ideal distance from the Sun to support life. This is known as The Goldilocks Theory.
July 23, 2009alice (texa,houston)what does iono mean from ionosphere?......and what is its temperatureThe ionosphere is made of ions and free electrons. In other words, when the sun radiation hits the atmosphere, it energizes some atoms to the point that they release electrons, and are left with an electric charge (while before they were neutral). These charged atoms are called ions.
July 22, 2009alice (houston)what does iono mean from ionosphere?......and what is its temperatureThe ionosphere is a region of the Earht's (and other planets!) atmosphere where atoms have lost electrons due to the solar energy, so it is formed by ions (charged atoms, which mean atoms with less or more electrons than its neutral state) and free electrons. Our web page The Ionosphere offers lots of information on this region.
July 20, 2009khun (Cambodia)How many percentage of rainfall does the earth absorb? And how many percentage of it turn to the atmospher?The amount of rainfall absorved by the ground varies from place to place. It depends on the vegetation cover, the kind of soil, artificial structures (roads, buildings, irrigation chanels), local topography, season, lat/lon, etc.
July 20, 2009mia (la)what are the 3 main factores that effect climateThey main factors that affect climate are: latitude, altitude, pressure systems, prevailing winds, distance from sea, ocean currents and great mountain barriers (pnemotecnic for memorizing: LAPPDOG)
July 20, 2009ayomide (california )can a comet knock the earth out of the solar systemThe amount of energy required for such thing would destroy our planet!
July 17, 2009mary (california )can a comet knock the earth out of the solar systemThe amount of energy required for such a drastic event would destroy the Earth!
July 17, 2009ayomide(mary) (california lancaster)can a comet knock the earth out of the solar systemThe amount of energy required for such a drastic event would destroy the Earth!
June 17, 2009Faryal (Indiana)A moon kind of comes about when it gets caught in the earth's atmosphere or something. What is the possibility that something else will get caught in Earth's orbit and Earth will have another moon?Very low. The orbit of our planet has been cleaned through Earth's life. This is one of the condition for a celestial body to be considered a planet.
June 16, 2009AlexanderIf the diameter of the Earth is 12,753 kms and the Sun is 1,400,000 kms, how is is possible that you say if the Sun is hollow, it would fit over 1 million Earths in it?Let's start with the fact that the Sun's diameter is about 100 times that of the Earth. This means that 100 Earths can be lined up to stretch across the face of the sun. Now, imagine the the Sun as an empty bowl, and let's try to fill it up with Earths. Now we can stretch the Earths in three directions (up and down, in and out and left and right, and everywhere in between). So, to fill the Sun we would need 100x100x100 = 1 000 000 Earths!
June 16, 2009Daizha (Mississippi)Do scientist believe in global warming?There is a broad agreement among most of the scientists about this issue. See our web pages IPCC: The Intergovernmental Panel on Climate Change, Intergovernmental Panel on Climate Change 4th Assessment Report , Tackling the Global Warming Challenge , and links therein for information on this topic.
June 2, 2009khbax (bankok)Why does the ratio of daytime and nighttime change?This is essentially due to the tilt of our planet's axis, the reason for the existence of seasons.
May 19, 2009SamDo you think global warming goes hand-in-hand with changing ocean currents, or are they entirely different? Are changing currents more likely to be caused by changes in salinity, changes in temperature, or some other factor? If currents did change, would it be possible to get them back to the state they're in now? If so, how long would it take? Is there any evidence of currents changing in the past? What affects (if any) would changing currents have on land?To answer all your questions would require more space that we have in this section, but our web page Predictions of Future Global Climate and the link therein offer the information you are looking for.
May 18, 2009Tatiana (united states of america ,ohio)How long will the earth live before it dies out?Considering the Sun as the most likely reason for Earth dismiss, then we have some time. In about 5 billion years (5000 000 000 years), the hydrogen in the center of the Sun will start to run out, the helium will get squeezed, and this will speed up the hydrogen burning. Our star will slowly puff into a red giant and will eventually eat all of the inner planets, including the Earth.
May 18, 2009shelbi (usa)what is the temperature for a rain forestThe temperature in a rain forest is commonly between 93 °F (34 °C) and 68 °F (20 °C).
May 18, 2009RUPESH (INDIA)TELL THE NAME OF THAT PERSON WHO PROVE FIRST THE EARTH IS SPHERICALEratosthenes was the first to calculate the circumference of the Earth, but the idea that our planet is round is much older. It is recognized that Pythagoras has one of the earliest recorded mention of the idea, in the VI century B.C.
May 12, 2009mike (Ohio, USA)Theoretically if you blew off the tops of the Andes mountains, would the rainforest, and desert balence out, and what would be the effect on the global climate?The answer to your question would require hundreds of especialists running their very complex models and discussing the results among them. Our climate is extremely complex, just one factor (top of the mountains) will not define the climate. Somethink like your idea would produce changes, for sure, but the consequences are very hard to calculate.
May 11, 2009johanna (philippines)when is the shadow become long and become short?Around noon shadows are shorter than early in the morning or late in the afternoon. Shadows are also long during winter at high latitudes.
May 11, 2009KK (NJ)I do not have an email adress and will earth end up dieing on its own, I mean like ..........in 1000 years,if it does please please please please please save us ,please please pleaseDon't worry, in about 5 billion years (5000 000 000 years), the hydrogen in the center of the Sun will start to run out, the helium will get squeezed, and this will speed up the hydrogen burning. Our star will slowly puff into a red giant and will eventually eat all of the inner planets, even the Earth.
May 7, 2009fredjenn (Philippines)what is oxygen-carbon dioxide cycleThe oxygen-carbon dioxide cycle is only part of the Carbon Cycle. Our page The Carbon Cycle offers a good deal of information on this topic.
April 30, 2009sally (virgina)how do u know that the ozone layer is fading?The Ozone Hole is a major "thinning" of the ozone layer in Earth's atmosphere. It was first noticed in the late 1970s. The hole appears in the winter over the poles, especially the South Pole. Various chemicals that humans release into the atmosphere help cause the hole. Special weather patterns near the poles in winter also help cause the holes to form. Our web page Ozone Holes shows two satellite images with a clear view of the holes.
April 28, 2009richard (GA)When the conditions for a rainbow to form are right. Why is there not more than one rainbow?Although just one rainbow is the most common sight, some times two and even three rainbows can be seen. Secondary rainbows are caused by a double reflection of sunlight inside the raindrops, and appear at an angle of 50°–53°.
April 21, 2009J.D. (California)what is the percentige of Eaths sea to land, or can you show me a pie chart,or do both! I need this for a report so please help me.Earth's surface is more than 71% water and close to 29% surface land.
April 20, 2009Lacy (Michigan)What kind of cloud typically produces a thunderstorm? ~please respond~Cumulus and Cumulonimbus clouds provide the most interesting and severe weather to our planet.
April 17, 2009ashleigh (ohio)what are 5 reasons that early earth and modern earth are different?The early earth was a very unfriendly place, without the protection of a dense atmosphere it was continuously hit by meteorites, there was intense volcanic and seismic activity, extreme temperatures, scalding rocks and choking fumes.
April 17, 2009austin (big lake ak)i want to know how metimorfic rocks form please neeed answers thank youHave you have heard that caterpillars metamorphose into butterflies? Rocks can metamorphose too! They change when they are in a place that is very hot with high pressure. One place like this is where the pieces of Earth's outer layer are crashing into each other. Much more information on our web page Metamorphic Rocks.
April 17, 2009angie (america)what are the four factor affects of climate?They are: 1. Latitude (the lower the latitude is, the more intense sunlight) 2. Air masses (certain air masses affect the temperature) 3. Ocean Currents (movement of the oceans) 4. Proximity to Water (seasons are milder near the oceans).
April 16, 2009monique (philippines)What are the components of kingdom plantae?Kingdom Plantae contains around 300 000 different species of plants.
April 16, 2009Clara (georgia/ usa)is the sun earths source of direct heat as well as light? if so why is it cold in antartica? i do not believe that the sun is earths sole source of heat. the heat comes from a layer, or expanse in the atmosphere when sunlight passes through it, and meets vapor just above the earth, heat is activated by sunlight, thats why it can be 100 degrees in the desert in daytime and 50 degrees at night. if the earth was heated by the sun, the inside of the earth would be hot and stay hot for a long time.we do no have direct heat from the sun, it would burn us up. have you ever heard of a tornado in anartica? the tilt of the earth does not cause seasons, it prevents extreme weather. the weather conditions are generated by the other planets in our solar system, which are really enemy planets. some of the planets are not to make a journey around the sun very often, but to act as fuel agents to ignite the earth,the earth is warming because it is moving closer to the sun as time goes along and is destined to burn up.The difference on the surface temperature at different latitudes lies on the striking angle of the sun rays. Around the equator the sun rays strike almost perpendicular to the surface, and most of the energy is transported to the surface. At high latitudes, the striking angle is much lower, and most of the energy is lost before reaching the surface.
April 16, 2009sarah (ney york(usa))where are volcanoes mostly found???Volcanoes are mostly found in narrow bands along the edges of the tectonic plates.
April 16, 2009sarah (ney york(usa))how do volcanoes change the surface of the earth?When surface volcanoes are born, a new landform (for instance, a mountain) is created. When they erupt new layers are added to the surface. If there is an explosion, the surrounding areas are affected (forests are burned, mudslides can wipe towns, the piroclastic flow can impact buildings, etc).
April 16, 2009raven williams (florida)What are Earths landforms?A landform is a feature of the earth's surface, such as plains, plateaus, mountains, hills, valleys, etc.
April 16, 2009SAMEERA (INDIA {lucknow})HOW THIS PLANET EARTH HAD BORN IN THE SOLAR SYSTEM?A widely accepted theory for the formation of the Sun (and planets, comets, etc) is that solar systems are formed when a cloud of gas and dust in space is disturbed, maybe by the explosion of a nearby star (called a supernova). This explosion make waves in space which squeeze the cloud of gas and dust. Squeezing made the cloud start to collapse, as gravity pulled the gas and dust together, forming a solar nebula.
April 13, 2009Ashley (NC USA)What causes the earth to rotate around its axis? Gravity? Or a magenet force?The rotation of the Earth, and other planets, about their axis is a remanent of the rotation of the planetary nebula from where all were formed.
March 24, 2009Gankanda (Sri Lanka)Can we make solar shild to reflect the sun radiation from worming the earth?For all effects, the Earth magnetic field is that shield. The geomagnetic field protects us from dangerous radiation from the Sun, deflecting the solar wind about 10 Earth radii (about 64,000 km [40,000 miles])upstream from Earth.
March 23, 2009KellieIn what layer of the atmosphere would you find the planets?The atmosphere of our planet is restricted to a relatively short distance from the surface. The rest of the planets are way too far from Earth to be considered near our atmosphere.
March 19, 2009Shane (New York)What enviromental problems do scientist face in the desert biome. What can be done to help themOne of the biggest threats to deserts is development. This page offers detailed information on this topic.
March 17, 2009louie (fl pinellas county)is the rotation 0f earth around the sun clock wise or anty clock wise?As viewed from the North Star Polaris, the Earth turns counter-clockwise.
March 16, 2009anne (pa)what is destroying the earthEssentially, we, the humans are behaving as a plague, destroying farming lands, producing greenhouse gases, and annihilating species. Hopefully, we have started to realize that we cannot continue abusing the planet as up to now. Let’s start acting responsibly before it is too late.
March 16, 2009raizen what are ingredients of sendimetary rocksfrom our web site What Is a Sedimentary Rock?: Many sedimentary rocks are made from the broken bits of other rocks. These are called clastic sedimentary rocks. The broken bits of rocks are called sediment. Sediment is the sand you find at the beach, the mud in a lake bottom, the pebbles in a river, and even the dust on furniture. The sediment may, in time, form a rock if the little pieces become cemented together. There are other types of sedimentary rocks whose particles do not come from broken rock fragments. Chemical sedimentary rocks are made of mineral crystals such as halite and gypsum formed by chemical processes. The sediment particles of organic sedimentary rocks are the remains of living things such as clamshells, plankton skeletons, dinosaur bones, and plants.
March 11, 2009sara (Florida/ USA)Is Niniru gravity going to stop the earths rotation for a couple days in 2012No. There is no any scientific fact that supports this.
March 11, 2009Nikky (Swaziland)do u believe that the continents we have today were once fitted together?Yes, it is the prevalent theory related to the plate tectonic. This figure shows the continents united in a super continente called Pangea.
March 10, 2009Andaya (US)what is a current theory on geoscience (on earth)that i could look up? i need to find one and ive been looking all over for one. geoscience is a very broad subject.Although the theory of Plate Tectonics has been around for some time, there is still a lot of scientific effort directed to its study. The previous link, and the links therein offer a good deal of information.
March 5, 2009Ashlee (arizona)"where is the floor,wall,raised rim,rays,ejecta on a impact crater? and is there a picture of all these names on a picture of a impact crater?This figure has the information you need.
March 2, 2009maria (OREGON)where are the youngest rock in the oceon found(geographic feature)The youngest rocks on the ocean floor are foun along mid ocean ridges and correspond to those that have just cooled from magma. Olderrocks are found farther from the mid ocean ridges.
March 2, 2009maria (OREGON)how does the magnetic reversal support the theory of seafloor spreading?Please, visit our web page Seafloor Spreading for a diagram that provides evidence of seafloor spreading by showing the ages of ocean floor in the Atlantic and eastern Pacific Oceans. These differently agged areas are also identified by their alternated magnetic polarity. When the lava that forms the floor cooled down, their atoms kept the existing magnetic polarity at the time. Because the magnetic reversal is a continuos process, the new crust had the inverse polarity and so on.
February 26, 2009Rachel (phillippines)what is the different kinds of volcano? because even in wikipedia i still can't find it,help me please..this is our assignment in science.Among the different kinds of volcanoes are: shield volcanoes, cinder cones, composite volcanoes.
February 24, 2009Louisa (NY)earth science self study geology regional metamorphism is associated w all plate boundaries, convergent, transform or divergent? I want to say divergent but diagram leads me to think convergent? Help Thank you!Metamorphism is associated with all 3 types of plate boundaries, but is most common at convergent plate margins.
February 20, 2009Kate (Philippines)WHAT ARE THE TYPES OF METAMORPHIC ROCKS AND PLEASE GIVE IT'S MEANING?There are three general types of metamorphic rocks: Low-grade metamorphic rocks form at temperatures of about 200 degrees Celsius. That’s a little hotter than the oven temperature needed to cook chocolate chip cookies! At this temperature, mica minerals grow as the rock changes. Intermediate grade metamorphic rocks contain mica as well as minerals such as garnet. High grade metamorphic rocks form in places that are so hot the rocks almost melt, about 800 degrees Celsius. One mineral that forms in this intense heat is sillimanite, which is often found in the rock gneiss.
February 13, 2009zack (kentucky)why is one ocean tide stronger then the other ocean tidePlease, visit our beb page Tides of the Oceans for detailed explanations on this topic.
February 13, 2009isela (california)what will we do if global warming takes place? where will we go?Due to the complexities of the natural processes, we just have a faint idea of what could be the consequences of the global warming. It is better to make a big, everybody-involved effort to stop the trend now, than to deal with the consequences.
February 13, 2009Liz (United States)I recently read that our days are now only about 16 hours long instead of 24. The reason provided was the increased pulses of the earth's "heartbeat". Can you confirm that this is true? Thank you.Our full day (understanding "day" as a full revoultion of our planet over its axis) is still very close to 24 hours. Maybe they were talking about the length of time from sunrise to sunset?
February 11, 2009yessenia (elizabeth,nj)what is a solar angle and how does it effect temperatures on earthNear the equator the Sun rays arrive to the earth surface almost at a right angle (90 degrees). For higher latitudes this solar angle decreases, and less energy (heat) is deposited on the surface.
February 10, 2009flutur (new york)how are earthquakes good for usI can only think of a reason: small earthquakes don't do too much damage, but are useful for the study of the Earth interior.
February 8, 2009Jarrell (Texas)How does the seasonal temperatures change with the alterarion of Earth's tilt? For example, if the earth's tilt would be 30 degrees instead of 23.5 degrees.If the axial tilt increases to 30 degree,the apparent latitudinal movement of the sun will increase. The seasons would be shorter, and the tropical zone will increase to about 39 degrees of latitud on both side of the equator.
February 8, 2009moustafa (egypt)what is the consolidation process in the rock cycle ?Sedimentary rocks are the result of lithification of sediments. Lithification involves consolidation and cementation. Consolidation is primarly related with pressure. The weight of overlying sediments results in compaction of lower layers.
February 8, 2009chris (usa)are the planets considered satellites to the earth?No. Planets move around a star, satellites move around planets. Our only natural satellite is the Moon.
February 8, 2009shekina (Australia)Where are we at this moment in orbit around the sun?For a detailed information on the position of the planets, including Earth, please visit The Astronomical Almanac of the U. S. Nautical Almanac Office .
February 6, 2009maria (texas)what would happen if the axis of the earth changed the angle of its tilt to 30 degrees?If the axial tilt omncreases,the apparent latitudinal movement of the sun will increase. The seasons would be shorter, and the tropical zone will increase to 39 degrees of latitud on both side of the equator.
February 5, 2009Toncy (India)Why is the rainfall more where there more trees?Although the general assertion is not exactly true, careful observation and records show that forests do affect rainfall to some extent, owing to their colder and moister air and the resistance which they offer to the movement of the winds. Read morehere.
February 5, 2009Darnell (Maryland, U.S.)HOW MANY HOURS OF SUNLIGHT THE NORTH POLE RECEIVE AT DECEMBER AND JUNE SOLSTICE?At the north pole there are 24 hours of daylight during the June solstice and 24 hours of night during the December solstice.
February 4, 2009bob (new zealand auckland)how much oxygen is in the atmosphere?The 20.95% of atmospheric molecules are Oxygen (O2). The total mass of Oxygen (O2) in the atmosphere is 1.1776 x 1018 kg.
February 3, 2009TedWhen people knew that the Earth was round and who found it?Since very early times the idea that Earth was spherical was being proposed. For example, Pythagoras in the 6th century BC held that all the celestial bodies were spherical. Around 330 BC, Aristotle provided observational evidence for the spherical Earth. Near 10 BC, the Greek geographer Strabo cited various phenomena observed at sea as suggesting that the Earth was spherical. The list is long, but it is clear that this idea of the round Earth was being discussed, and accepted, since long ago.
February 2, 2009marisol (ga)what is a clastic rockClastic rocks are composed of fragments, or clasts, of pre-existing rock (for example, sedimentary rocks)
February 2, 2009hannah (philippines)what are some example of Biome??These are the different types of biomes. Follow these links to learn more about the plants and animals that live in each one: Tundra, Taiga, Temperate forest, Tropical rainforest, Desert, Grassland, and Ocean biome.
January 30, 2009Lila (OHIO)How dose a volcano eruption alter change the earth's surface?A volcano eruption is a significant event for the areas around the volcano. Depending of the type of eruption, there can be disastrous mud flows, very fast moving masses of ash and other particles, lava can flow down the mountain burning everything on its path. Due to these events, forests in the eruption area can be destroy, homes and other properties can be damaged or even covered or burnt, crops, farm animals, roads, etc. are also subject to the effects of a volcano eruption.
January 29, 2009Mehdi (France, Reunion island)What is the impact of the cocolitophore on climat and food chain ?If your question is about the impact of climate on cocolithophore and food chain, then the answer is simple: University of Hawaii oceanographer Dave Karl, a member of the National Academy of Sciences, has said that oceanic acidification could become one of the most significant affects of the increasing amount of carbon dioxide in the atmosphere. A more acid ocean interferes with the ability of animals and plants to create calcium carbonate, the stuff that makes up limestone, coral, seashells and, among other things, the protective outer layer of a class of organisms called cocolithophores that are at the base of the marine food chain. Extracted from this article.
January 28, 2009kajal (karnataka/india)my teacher taught us that the earth's geiod shape is due to earth's rotation.how far is it proved sir?There are strong (and well known) forces acting over a rotating body. Such forces have been calculated for our planet with a high accuracy. They explain the shape of Earth.
January 26, 2009bob (st. pete)How far from earth is the sun?Earth Minimum Distance from Sun is 146 million km (91 million miles) and its Maximum Distance from Sun is 152 million km (94.5 million miles).
January 23, 2009justin wade (alabama/america)what is the ecosystem likeEcosystems are the interactions between the living things and the nonliving things in a place. In an ecosystem, the plants, animals, and other organisms rely on each other and on the physical environment – the soil, water, and nutrients, for example. Even though they are living in the same place, each species in an ecosystem has its own role to play. This role is called a niche. The niche for one species might be to climb trees and eat their fruit, while the niche for another species might be to hunt for small rodents. For a tree, a niche might be to grow tall and make food with the Sun’s energy through the process of photosynthesis. If the niche of two species is very similar, they might compete for food or other resources.
January 23, 2009justin (alabama/america)where on earth is the ecosystemBiomes are large regions of the world with similar plants, animals, and other living things that are adapted to the climate and other conditions. They are: Tundra, Taiga, Temperate forest, Tropical rainforest, Desert, Grassland, and Ocean biome. A biome is made of many similar ecosystems. An ecosystem is often much smaller than a biome, although the size varies.
January 23, 2009Seku yehsu (MN)How does solar energy vary with respect to latitude?The amount of solar energy reaching Earth at any particular latitude is defined by how the Earth orbits the Sun. Therefore, it is a function of the time of year and the tilt of the Earth with respect to the Sun. Use the applet in this page to explore how the incoming energy from the sun varies with time of year and latitude.
January 23, 2009MorganCurious what the state of this research on small comets bringing water to earth currently is.PLease, visit our web page Small Comets Bring Water to Earth for information about this topic.
January 22, 2009khadijah (lousiana)what are the seven time periods in the paleozonic time periodThe paleozoic is usually divided in the following key events: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permia.
January 21, 2009char (cyprus)how were continents formed??Initially, there was a huge land mass known as Pangea, that was later divided in to the continentes that we know today by the plate tectonics.
November 5, 2008Taylah (USA)What would happen if all the ice melts?The global sea level would rise significantly (covering low lands all around the planet), the weather patterns would be affected, and even there could be a food availability disaster (much farmland is located at low elevations).
November 4, 2008SHIKHA (INDIA)According to the universe which year is going on and when will the earth explode?There is no known reason for the Earth to explode, unless it is hit by another cosmic object of considerable dimensions, and so far scientists haven't found any in a collision path.
November 3, 2008ritu (india/gujarat)how water has enter to our earth?The issue of the origin of water in our planet is still being debated. The main theories are the cooling of the primordial Earth (our planet cooled to a point when the outgassed volatile components were under enough pressure for the stabilization snd retention of liquid water), and extraterrestrial bodies (objects beyond Neptune’s orbit, rich in water, impacted our primordial planet, dropping water in the process). Other theories are related with biochemical and physical processes.
October 21, 2008jesse (australia)what warninigs were given to the people when krakatoa eruptedStarting on May 20, 1883, and for about three months, Krakatoa was rumbling and belching harmlessly, and many people thought that the volcano was releasing energy and no danger was to be expected. That was until the events of the 26 and 27 of August, when the explosions started.
October 16, 2008Christine (SC)How was Mount Blanc formed? Hurry!!!About 770 million years ago, an upheaval of the earth's crust formed an under laying axes of the Alps range. Four succesive glaciations formed in the Quartenary era (an ice age) helped to sculpt the present profile of the Mont Blanc range. More information here.
October 9, 2008Jayden (Alabama)What is the difference between a savanna and a grassland?There are several types of grassland. They are distinguished by different names like plains, prairies, savannas and pampas. MOre information in our web page Grassland Ecosystem.
October 9, 2008fara (malaysia)what is it mean by 'aurora',the northern light?what cause it?sunlight or earth magnetic field?The auroras are a beautiful manifestation of the link between space and our planet. The aurora is formed when protons and electrons from the Sun travel along the Earth's magnetic field lines. These particles from the Sun are very energetic causing the gases of the atmosphere to light up like the gases of a streetlamp! More information on our web page Auroras.
October 3, 2008Daisy (Philippines)what is the blanket of the earth?Different things could be called "blanket" of our planet. The atmosphere is Earth's blanket of gases, the ionosphere (composed of ions and electrons) also works as a blanket since it absorbs some radiation. The magnetosphere (Earth's magnetic field) is our shield of many different radiations from space.
October 3, 2008Daisy Rie (Philippines)what is the blanket of the earth?Different things could be called "blanket" of our planet. The atmosphere is Earth's blanket of gases, the ionosphere (composed of ions and electrons) also works as a blanket since it absorbs some radiation. The magnetosphere (Earth's magnetic field) is our shield of many different radiations from space.
October 1, 2008luisa (new zealand)why does the earth rotate around the sun?The Earth and the rest of the planets, comets, etc. rotate around the Sun as a result of the formation of our Solar System: The Sun and the planets formed as a result of the gravitational collapse of accreting material. This material was part of the solar nebula, and transferred its rotational motion to the planets, accelerating as its radius of rotation decreases.
September 30, 2008Kaylan (AZ/USA)How many times during the year would the sun's rays strike perpendicular in Honolulu Hawaii, Phoenix, AZ and Sorocaba, Brazil?Outside the tropics (north of the Tropic of Cancer, 23.5° N, or south of the Tropic of Capricorn, 23.5° S), the Sun would not be directly overhead at any time during the year. Inside the tropics, the Sun is directly overhead twice each year, around March 21 (vernal equinox) and September 21 (autumnal equinox). Now you just need to look for the latitudes of those points to find the answer.
September 30, 2008chinmaye (india)is any danger to earth if yes,how.The most immediate danger to our planet is our own uncontrolled use of non-renewable resources, and the dumping of contaminants on soils and on the atmosphere. Climate changes, especially global warming, could seriously affect our planet.
September 30, 2008ashley (fl)when plates move apart, what forms?Tectonic plates pull apart at spreading ridges.
September 30, 2008KOmbe (Taxas)How would the seasons be affected where you live if the tilt of the earth's axis of rotation increased from 23.5 degrees to 40 degrees?There is no doubt that significant changes will affect our planet with such a drastic change on the tilts of its axis. For starters, the tropics would expand up to about 40 N to 40 S latitude, and the northern and southern temperate zones would have much more equalized temperatures.
September 26, 2008April (Utah)Related to the orbit of the planets around the sun, if the sun can hold what is it 10000 earths, then what is DIRECTLY behind the sun in the extact same orbit as us?Nothing. Only our planet and its moon follow this orbit.
September 26, 2008likita (georgia)what force drives the movement of tectonic plates?The main force that shapes our planet’s surface over long amounts of time is the movement of Earth's outer layer by the process of plate tectonics. Movements deep within the Earth, which carry heat from the hot interior to the cooler surface, cause the plates to move very slowly on the surface, about 2 inches per year. There are several different hypotheses to explain exactly how these motions allow plates to move. More information on our web page Plate Tectonics and links therein.
September 26, 2008shashank (india)what is the rainfall conditions in cold desertThe annual precipitation in Antarctica is so low that Antarctica is really a desert, and in fact the interior parts of the continent get less precipitation every year than the Sahara dessert! MOre information on our web page .
September 25, 2008Ken (Mississippi USA)Has the Earth always tilted or, did the flood cause it?It is assumed by many scientists that Earths axis was tilted very early in the evolution of our planet, when a object around the size of Mars struck Earth.
September 24, 2008Chinmay (India)The heating of the parts of the atmosphere by say ozone(absorption of UV radiation) must be balanced by a cooling process to maintain the temperature.How does tis occur?Part of the enrgy that reaches our atmosphere is used in the production of new elements, especially at the ionosphere, that owes its existence to the UV solar rays. Some of these ions and electrons recombine later on, releasing the energy back. The atmosphere also reflects sunlight back to the space, and part of the heat is stored in the ocean and land.
September 15, 2008dani (canada)i wanna to ask tht is it true tht in 2012 we all living beings are going to die and our earth is going to explode?No, there is no a scientific reason for such a disaster and extinction to happen!
September 15, 2008christine (philippines)what is an ecosystem?An ecosystem is a region of land that has its own unique climate and life. The amount of rainfall, temperature and sunlight makes each region the way it is. Each biome is filled with plants and animals that have adapted to that land. All together, the land and its life is called an ecosystem. More information in our web page Ecosystems.
September 15, 2008christine michaela joy (philippines)what is an ecosystem?An ecosystem is a region of land that has its own unique climate and life. The amount of rainfall, temperature and sunlight makes each region the way it is. Each biome is filled with plants and animals that have adapted to that land. All together, the land and its life is called an ecosystem. More information in our web page Ecosystems.
September 11, 2008Antoinette (Arizona, USA)Where in the atmosphere are satellites found?Different satellites operate at different altitudes. For example, GPS satellites are at an altitude of approximately 20 200 kilometers, while the COSMIC satellites are at an altitude of around 750 km. In general it can be considered that the satellites are moving at the exosphere level.
September 10, 2008Janeth (Texas)what is the lenght of orbit ("year") of the earth?The lenght of an Earth year is 365 days 5 hrs.
September 10, 2008Janeth (Texas)what is the lenght of the rotation ("day") of the earth?It is generally accepted that the lenght of the day in our planet is 24 hours.
September 9, 2008DeanDo you have any information about the moon's affects on volcanoes?It is not my area of expertise, but I think you will find this article interesting (and supporting of your ideas).
September 9, 2008madeline (Australia)What happens if the atmosphere gets too thick?Your question is to wide to answer in detail, but there are two important factors to keep in mind, possible changes in the composition, and an increase in the atmospheric pressure.
September 8, 2008mizzy (australia)Where do the main Greenhouse gases come from?There are natural and human-related sources of greenhouse gases, among them are industrial development, fossil fuel burning, deforestation and agricultural practices, etc. The combination of these factors have led to an increase in the atmospheric concentration of gases such as carbon dioxide and methane, the gases that are responsible for the greenhouse effect.
September 8, 2008JulianEverybody knows that the continents are in ceaseless movement. What direction are we moving to? I mean my country: Argentina.Hola Julian, Tu inglés es impresionante, pero te respondo en español, que es nuestro primer idioma. Argentina está casi en el borde oeste de la Placa Sudamericana, que se mueve al oeste. Al frente, sobre el Pacífico, tiene la Placa de Nazca, que interacciona con la Sudamericana en una zona de subducción, es decir, la Placa de Nazca se desliza BAJO la Placa Sudamericana.
September 4, 2008karyn (philippines)would you please explain to me briefly what the sulfur cycle is all about? thanks.The sulfur cycle can be described as follows. Most of the sulfur in our planet is stored in rocks or buried deep in oceanic sediments. There also is sulfur in the atmosphere. Sulfur reaches the atmosphere through both natural (for example, volcanic eruptions, bacterial processes, evaporation from water, or decaying organisms) and human sources (mainly a consequence of industrial processes). In the atmosphere, sulfur reacts with oxygen, water or other chemicals. The particles produced react with rain and fall as acid rain. The particles will than be absorbed by plants again and are released back into the atmosphere.
September 3, 2008David (USA)I just read an articale on www.cnn.com that says scientist are saying there is 50/50 chance that the North Pole will be ice free for a short time this September. Do you have any updated pictures of the North Pole?This is a recent picture of the North Pole.
September 3, 2008Katie (Wisconsin)What natural or human-related activities could raise or lower the Earth's planetary albedo?Just an example. The releasing of particulates to the atmosphere can contribute to the formation of clouds (if they will precipate is another question). The presence of clouds affects the albedo of our planet. PLase, visite our web page Aerosols and Cloud Formation for more information.
September 3, 2008sedew (india)how much of earth's surface is covered by forests?Tropical forests are restricted to the small land area between the Tropic of Capricorn (latitudes 22.5° North) and the Tropic of Cancer (22.5° South). Not long ago, tropical rainforests covered as much as 14 percent of the Earth’s land surface, but today less than 5 percent of Earth's land is covered with these forests (about 2.41 million square miles).
September 2, 2008sidney (Nigeria)can you please sent me the website where I can find the history of the earth's revolution?Our website Earth offers a huge amount of information on this topic. Furthermore, a simple google search brings a good number of findings. Just two examples: http://sci.waikato.ac.nz/evolution/EarthHistory.shtml http://www.geocities.com/capecanaveral/lab/2948/originoflife.html
September 2, 2008Denis (Uganda)what is the amount of fresh water on the earth and how much is it accessible for human use?From all the water on Earth, just about 3% is fresh water. The majority, about 69 percent out of this 3%, is locked up in glaciers and icecaps, mainly in Greenland and Antarctica. Another 30.1% is ground water, and the rest includes fresh surface water (river, lakes, swamps, etc.)
September 2, 2008Ken (MD)Why do we not see the hottest temperatures of the northern hemisphere summer at the summer solstice? It's always hottest later, like late July/August, when I'd think it should be getting progressively cooler.Our planet have a huge heat capacity. There is always a balancing process between what we received from the exterior, and the amount of heat energy stored near the surface in our planet. This is the reason to observe the highest temperature later.
September 1, 2008raven (india)why is the earth compressed from its poles?This effect is related with the spinning motion of our planet on its axis. The centrifugal force (the apparent force in a rotating system that deflects masses radially outward from the axis of rotation)increases towards the equator and decreases towards the poles.
August 29, 2008mary (phillippines)how far earth to the sun?For Earth: Minimum Distance from Sun: 146 million km (91 million miles) Maximum Distance from Sun: 152 million km (94.5 million miles)
August 25, 2008Tina (U.S.)What are the names of the metals that make up the Earth's Crust?The Earth crust is composed of thin silicate rock material. There are 90 known elements in the Earth’s crust, and they combine to form minerals (there are around 3 700 known minerals in the Earth’s crust).
August 24, 2008MANNJU (MALAYSIA,SELANGOR)tell me about the thinning of the ozone layer.We have several pages dedicate to this topic. If you please, you can start with our page Ozone - An Overview and follow the links therein for further information.
August 24, 2008Clare (Sydney,Australia)How do sunspots affect the Earth's weather?Although correlations between solar activity, global temperature, and rainfall have been observed, the link is still not clearly established, and there is no consensus among scientists as to whether sunspots actually affect the earth's weather or not.
August 21, 2008Maureen (New Jersey)How many 1 degree latitudes are there in the northern half of the globe?Both halves of the planet run from 0o to 90o. 0o corresponds to the equator, and 90o to the poles.
August 21, 2008Diana (new zealand)What motion causes the movement of the moon through the sky each night ? thanksThe most visible effect of the Moon on our planet are the tides. Our web page Ocean Tides explains this effect in detail.
August 20, 2008Sara (England)how does the earth's interior processes affect the earth's surface?From the magnetic field that shield our planet to the plate tectonics that constantly reshape it, many characteristics of Earth are determined by proccesses in the interior.
August 19, 2008william (tennessee)what rocks can be changed into sediment by weathering and erosion: sedimentary, igneous, metamorphic or all of them. thanksAll of them! These processes afect all kind of rocks and are an important part of the Rock Cycle.
August 18, 2008brittany (tas)what are the polar regions?Our website Plate tectonics and people to answer your question in detail. From there I extracted the following information, "Since the year A.D. 1600, nearly 300,000 people have been killed by volcanic eruptions."
August 18, 2008Wilson (Minnesota)Fossil graveyards have fossilized animals, but why are the animals from different climates?You are absolutely right! This is related to the fact that the different regions of our planet have had different climates during their geological history. For example, good part of Colorado was under the sea, and the Sahara had at some point a fresh, green climate.
August 14, 2008Tanja (Croatia)Why is summer daylight in Helsinki longer than New York?Helsinki latitude is 60°10' N while New York is at 40°47' N. Due to the different inclination of the Sun over the horizon, summer days are longer at higher latitudes.
August 14, 2008zeyna (australia)what type of rock is the three sistersThe soft sandstone of the Blue Mountains is easily eroded over time by wind, rain and rivers, creating espectacular formations like the Three Sisters.
August 14, 2008Elizabeth (Free State)South Africa has a lack in water supply & it is estimated that in a few years time,it will not have any water at all.Where are all the water in South Africa going to?I recommend to visit the web page Water Issues to find answers to your question.
July 8, 2008stuti (india)how many chloro fluro carbons does an air conditioner emit in 1 hour?how does the CFC's deplete the ozone layer?Please, visit our web pages The Greenhouse Effect & Greenhouse Gases and Repairing the Antarctic Ozone Hole! for in-depth information on this subject.
July 8, 2008simran (canada)what does the earth's layers have in them?The core is composed mostly of iron (Fe) and about 10% sulphur (S). The mantle, which is composed of iron (Fe), magnesium (Mg), aluminum (Al), silicon (Si), and oxygen (O) silicate compounds. The crust is composed of the least dense calcium (Ca) and sodium (Na) aluminum-silicate minerals.
July 3, 2008ARIF (ENGLAND)WHATS IS THE EFFECTS OF WATER POLLUTION ON LIVING THINGLife, at least the kind we know, is not possible without water. However, contaminated water can be extremely perjudicial to life. More information here.
July 3, 2008kembreia (las vegas)what does the ecosystem look like?An ecosystem is a region of land that has its own unique climate and life. The amount of rainfall, temperature and sunlight makes each region the way it is. Each biome is filled with plants and animals that have adapted to that land. All together, the land and its life is called an ecosystem. More information in our web page Ecosystems.
July 3, 2008kembreia (las vegas)is the ecosystem changing?Absolutely, all ecosystems are changing. This is a continuous process that can be accelerated by external factors like global warming.
July 3, 2008kitauge (louisiana)How do location on earth and the angle of sunlight affect temperature?At the equator (latitude = 0o) the sun rays hit the atmosphere vertically, which makes possible that most of the rays reach the Earth surface. For higher latitudes, the angle varies from 90o to almost 0o at the poles. With the smaller angles, more sun rays are reflected back to the space, and less energy reach the surface, which is the main reason for the colder climates.
June 30, 2008vainess (tanzania)please explain more about soltice.There are two solstices in a year, when the tilt of the Earth's axis is oriented directly towards or away from the Sun, causing the Sun to appear to reach its northernmost and southernmost extremes. In other words, solstices are the two times of the year when the sun is at its greatest distance from the celestial equator. For more information visite our web pages Summer Solstice and Winter Solstice.
June 30, 2008javockie (ms)what is the size of the earthOur planet diameter is 12 753 km (7,926 miles), its mass 5.98x1024 kilograms (6.521 tons), and has a density of 5 515 kg/m3.
June 30, 2008blh (california)Why dosen't the Earth stop rotating?Earth's angular momentum is tremendous. The amount of energy required to slow down our planet is proportional to this angular momentum. There are forces slowing down the planet, but at a very small rate. For example, Earth lost 0.63 milliseconds (0.00063 seconds) per day in the 12-month period from July to June 2001.
June 27, 2008Bailee (Utah,America)What would happen if the Earth's magnetic pulse was stable? How can you measure it when there is pulses?Variations on the various components of our planet's magnetic field are recorded by magnetometers distributed around the world. Many of these variations are caused by the interaction of the magnetic field with the solar wind.
June 25, 2008Travis (Texas)how is carbon removed from the armosphere?Carbon is removed from the atmosphere is several ways. The two most important are: Plants: Using the sunlight plants perform photosynthesis to convert carbon dioxide into carbohydrates, releasing oxygen in the process. Oceans: Near the poles, where the surface water becomes cooler, more carbonic acid is formed as CO2 becomes more soluble.
June 23, 2008Leah (Ohio/U.S.A.)Cinder Cone Volcanoes are said to erupt only once but what keeps them from erupting more than once?Cinder cone vlcanoes do erupt, in general, more than once. For example, since Cerro Negro volcano (Nicaragua) was born in 1850, has erupted more than 20 times, most recently in 1995.
June 18, 2008BainWHY DO TORNADOES COME MOSTLY DURING THE SPRINGTornadoes can occur on any day of the year and at any hour, but the most violent tornadoes form during the spring and summer; when the strong thunderstorms that produce them are more frequent.
May 28, 2008Vainess (Tanzania)is the earth flat or spherical?Since long ago our planet has been known to be espherical, and with the artificial satellites on orbit around the planet, we can now see it clearly from pictures taken by them.
May 22, 2008glady (Tanzania)What is the name given to the earth's shape?The Earth's precise shape is known as the geoid. It is very close to an oblate spheroid (a rounded shape with a bulge around the equator).
May 14, 2008Matt (U.S.A.)How do humans contribute to global warming?There are many ways in which humans affect the planet, including our contribution to global warming. One of the most drastic is the production of CO2, carbon dioxide, through industries, agriculture, and the use of fossil fuels. Please, visite our webpage Climate and Global Change for additional information.
May 13, 2008colin (florida)What occurs when the sun is directly over the equator?This corresponds to the equinoxes, which occur two times per year: the Autumnal Equinox (September 22nd or 23rd), and the Spring Equinox (March 20th or 21st).
May 8, 2008sharanya (karnataka(India))Because of gravity , why does not the earth fall on the sun?Because it is kept in orbit by a combination of the gravitational (centripetal) force and the centrifugal force. The first one atracts the Earth, and the rest of the planets, toward the Sun, but the second one tries to force the earth to escape. A balance between them keeps the earth in place.
May 7, 2008cristina (us /florida)what is the size of the earth ?The diameter of our plnet is 12 753 km (7,926 miles), and it has a mass of 5.98x1024 kilograms (6.5x1021 tons).
May 2, 2008Wendy (Philippines)Cite natural phenomena proving that the earth's interior part is very hotVolcanoes, seismic activity, hot spots, mid-ocean ridge, etc. are manifestations of a hot core at the center of our planet.
April 30, 2008George (Macau)What causes tides?Due to the mutual gravitational atraction between the Earth and its moon, there are forces acting over both. In the case of our planet, the only element that can be moved is liquid, and the bigger bodies of water show the effects of this atraction in the form of tides.
April 29, 2008hunter (canada/dunnvill)whatdo you know about Mt.Vesuvius?There are many websites with information about Mt. Vesuvius, for example this one is very interesting.
April 24, 2008Tina (Pennsylvania)Why does the polarity of the earth's magnetic field switch from north to south and back again?The process of magnetic field reversing is not completely understood although it is supposed to be related to process in the mantle. This page offers more information, especially the last topic.
April 23, 2008SarahHow do tornados form and whereTornadoes form from severe thunderstorms. They have a very high energy density which means that they affect a small area but are very destructive to that area. They also don't last very long which makes it hard to learn about them. More information in our website Tornadoes.
April 22, 2008Sammyhow does a tornado form and how and what is a tornadoe and where does it take placeTornadoes form from severe thunderstorms. They have a very high energy density which means that they affect a small area but are very destructive to that area. They also don't last very long which makes it hard to learn about them. Since they're hard to study, they're also hard to forecast. People know even less about tornadoes, which is why there are a lot of different myths that aren't true. Much more information on this topic can be found in our web page Tornadoes and the links therein.
April 17, 2008shyanne (pennsylvania)how is a tsunami formed?Undersea earthquakes, which typically occur at boundaries between Earth’s tectonic plates, cause the water above to be moved up or down. Tsunami waves are formed as the displaced water, which acts under the influence of gravity, attempts to find a stable position again. More information in our webpage How Tsunamis Form.
April 14, 2008Diana (New Jersey)What and how is a tsunami createdA tsunami is a series of waves generated in an ocean or other body of water by a disturbance such as an earthquake, landslide, volcanic eruption, or meteorite impact. The picture at the left shows how an earthquake can generate a tsunami in the overlying water. Undersea earthquakes, which typically occur at boundaries between Earth’s tectonic plates, cause the water above to be moved up or down. Tsunami waves are formed as the displaced water, which acts under the influence of gravity, attempts to find a stable position again. More information in our webpage How Tsunamis Form .
April 10, 2008mike (ca, usa)is the amount of time change in a day in a complete summer to winter cycle the same amount of change each day or varible thruout the seasonInteresting question. I would say that the amount of time change is not constant during the seasons. All objects in an elliptical path follow Keppler three laws, and one of them describes how the speed of the object increases when it is near on of the focus of the orbit, in this case the sun.
April 9, 2008Christian (Virginia, USA)What is the air density of the ionosphere? I need to know right away for a project. I've been looking everywhere for the answer.The ionosphere consists of several layers at different heights. More information can be found in our page Ionosphere and links therein. This page shows a plot with the ionosphere densities.
April 7, 2008anjali (singapore)if there must be a planet that has to be destroyed what would you say in order not to destroy planet earth? could you give me five reasons and in detail-thank youOur planet is a significant depository of water and oxygen, it has abundant carbono-type life, and it is where we live!!!
April 3, 2008Beatriz (new york/ united states)How does the color of a background affect its absorption of solar insolation?Lighter colors will reflect more solar energy, and darker colors will absorve more energy. For example, icy surfaces reflect more energy than the ocean surface.
April 3, 2008Giselle (NY)why do we have seasons?how many are they? how long d they last?The inclination of the axis of our planet is the reason for the seasons. See our page Earth's Tilt Is the Reason for the Seasons! for more information.
April 3, 2008Gaige (Illinois)Is there any way to stop a big Earthquake?Scientists are working hard trying to predict and mitigate the effects of earthquakes, but once the energy that produces a quake is released, it will be almost impossible to stop or divert it.
April 1, 2008niniveh (philippines)how does greenhouse effect work?Like in a greenhouse, where the glass ceilings don’t let heat escape, gasses in the atmosphere can trap the heat that normally would escape to the space, raising in this way the temperature in our planet.
April 1, 2008niniveh peralta (philippines)how does greenhouse effect work?Like in a greenhouse, where the glass ceilings don’t let heat escape, gasses in the atmosphere can trap the heat that normally would escape to the space, raising in this way the temperature in our planet.
April 1, 2008Bailey (IL)What is the average temperature on EarthThe average range of temperature in our planet is -89oC to 57.7oC (-128oF to 136oF).
March 31, 2008Josh (Ohio)how would you explain the nitrogen cycle?Nitrogen is an element. It is found in living things like plants and animals. It is also an important part of non-living things like the air above and the dirt below. Atoms of nitrogen don't just stay in one place. They move slowly between living things, dead things, the air, soil and water. These movements are called the nitrogen cycle. More information in ouir web page The Nitrogen Cycle.
March 28, 2008julia (california)why are the amounts of gases in the atmosphere measured in percentages of dry air?The water content is not included in the calculations for the purposes of comparisons because the amount of moisture in the air is extremely variable across our planet.
March 28, 2008julia chen (california)why are the amounts of gases in the atmosphere measured in percentages of dry air?The water content is not included in the calculations for the purposes of comparisons because the amount of moisture in the air is extremely variable across our planet.
March 28, 2008shamari (virginia)how do humans impact the earth negatively?There are many human activities that affect the environment, from the consumption of fossil combustibles that emit carbon dioxide to the atmosphere, to the burning of forests in many places of the planet, we have been abusing indiscriminately our planet, and the effects are already being felt.
March 28, 2008rosette (davao, philippines)does the position of the earth affects the climate or weather of a certain area?The inclination of the axis of our planet is the reason for the seasons. See our page Earth's Tilt Is the Reason for the Seasons! for more information.
March 28, 2008rosette (davao, philippines)why is it that the earth's position is tilted?The tiltiing of our planet axis most likely happened at the beginning of the solar system formation, four and a half billion years ago, when dust and rocks were floating around and frequently crashing into each other. One or more of these impacts tilted our axis.
March 27, 2008nany (massachusetts)how is new crust formed?New crust is formed when molten rock or magma rises from the mantle to fill the gap between tectonic plates as they separate.
March 27, 2008tanaiya (Dallas TX)what are rocks that have been changed by high heat or very high pressureMetamorphic rocks are rocks that have been exposed to very hot temperature and high pressure. Some rocks only change a little, while others change a lot. When a rock is metamorphosed, its mineral crystals change. Usually, the same chemical ingredients are used to form new crystals during metamorphism. Sometimes new types of minerals grow that weren't in the rock before.
March 27, 2008Kim (Mexico City,Mexico)What is a igneous rock?I need a definition?Igneous rocks form when molten rock cools and becomes solid. Molten rock is called magma when it is below the Earth’s surface and lava when it is above. More information on our web page Igneous Rocks.
March 27, 2008victoria (philippines)mohorovicic discontinuityThe Mohorovièiæ discontinuity (A.K.A the Moho) is the boundary between the Earth's crust and the mantle.
March 25, 2008Aleyda (Florida, Miami)Why are the seasons in the Southern Hemisphere opposite to those in the Northern Hemisphere?Because the seasons are origined because the tilt of the Earth. Our web page Earth's Tilt Is the Reason for the Seasons! discusses this topic in detail.
March 21, 2008Khadem (Ontario)We know about the Bermuda Triangle. I have seen articles claiming that this phenomenon is due to some disturbed magnetic field of the earth. How much is this true? Can satellite pictures be used to answer the mystery of missing ships? Doesn't scientists consider Bermuda Triangle a high priority of research?The Bermuda Triangle phenomenon, when scientifically observed, shows a very different side. This article discusses the topic.
March 20, 2008Adriana (new mexico)what percent of each continent is covered by grasslans?Please, visit our web page Grassland Ecosystem for information on this topic.
March 18, 2008samantha (MI)what is winter solstice?For the northern hemisphere this corresponds to the point where the planet's axis is tilted at its most away from the sun, and marks the shortest day and the beginning of winter. In the southern hemisphere this is the summer solstice.
March 17, 2008Christen (Utah)The Alvin submersibile is used to explore the depths of the ocean. Just hows deep are trenches in the ocean?The deepest trebch in the Pacific Ocean is the Mariana Trench with 10 900 to 11 000 meters. In the Atlantic Ocean it is the Milwaukee Deep with 8 605 meters.
March 14, 2008Tara (Arizona, USA)If the moon's gravitational pull is one-sixth that of Earth's, then how does the moon pull the ocean water towards it (overcoming Earth's gravity), causing high tides? Thank you! I love this site!Your values are right, but there a vectorial addition that explains the tides on both sides of Earth. See this article for a nice discussion on this topic.
March 12, 2008Bailee (Utah, America)What is the Earth's magnetic pulse?Our planet's magnetic field is not stable. Frequent undulations, lasting from seconds to minutes, are called micro-pulsations. These are frequently known as pulses.
March 11, 2008Rowanne (Philippines)What kinds of currents Peru Current and California Current are?The Peru current consists of cold water and runs on the northwest coast of Peru. The California Current moves south along the western coast of North America. The movement of northern waters southward makes the coastal waters cooler than coastal areas of comparable latitude on the east coast of the United States.
March 11, 2008Doug (Michigan)What would earth's season be like if earths axis was straight up and down?In this case, we will have very consistent seasons all year around. The difference will be now mainly latitudinal, with coldest climates for higher latitudes.
March 10, 2008Adam ()When is hurricane season?The Atlantic hurricane season is officially from June 1st to November 30th.
March 10, 2008Chelsea (Canada)Why does a storm often lessen in intensity when it hits land?Storms are "heat engines" that require of the warm oceanic water to exist. The lack of warm water convection feeding the storm is the reason a hurricane weakens when it moves over land.
March 10, 2008Emily (Florida)If it is winter in canada what seson is it in argentinaThe seasons are caused as the Earth, tilted on its axis, travels in a loop around the Sun each year. Summer happens in the hemisphere tilted towards the Sun, and winter happens in the hemisphere tilted away from the Sun. As the Earth travels around the Sun, the hemisphere that is tilted towards or away from the Sun changes. So, when winter is arriving in the northern hemisphere, the southern hemisphere is enjoying the summer season.
March 5, 2008Laurenna (U.S.A)During March and September the Earth receives an equal amount of energy and yet autumn is cooler than spring. Why is this?Because the sun rays, due to the tilt of earth axis, arrive to your particular hemisphere in a lower angle during autumn, thus making the energy transfer less efficient (more of the energy is reflected back to space).
March 4, 2008abby (ohio - usa)In December, Canada enters the winter season. What season is it in Argentina?The seasons are caused as the Earth, tilted on its axis, travels in a loop around the Sun each year. Summer happens in the hemisphere tilted towards the Sun, and winter happens in the hemisphere tilted away from the Sun. As the Earth travels around the Sun, the hemisphere that is tilted towards or away from the Sun changes. So, when winter is arriving in the northern hemisphere, the southern hemisphere is enjoying the summer season.
February 28, 2008(California)How does the Earth's tilt on its axis affect climate?The tilt of our planet axis is the motive for of the seasons. For a good description of this relation, visit our web page What Causes the Seasons? and the links therein.
February 28, 2008alma (des moines iowa)what are continental plates made up of?The continental crust is composed of granitic rocks which are made up of relatively lightweight minerals such as quartz and feldspar.
February 25, 2008Tiana Nguyen (California, Orange County)what color is earth?Our planet is of a wonderful blue when seen from space. radioactive decay. Eventually a balance will be reached and our planet will cool down.
February 12, 2008cris (washington)When is the summer solstice for the N. Hemisphere in 2007-2008?For the N. Hemisphere the solstice occurs begins: 2007-06-21 at 18:13, and 2008-06-21 at 00:00.
February 8, 2008Sakura (Austalia)What is the likely outcome of the greenhouse effect in 100 years?The answer of your question greatly depends on how Humans act now and in the near future. A continuos accumulation of greenhouse gases will be devastating for our planet.
February 8, 2008DJ (New Zealand)What/who is earth named after?
Ta!
There are many theories about our planet name. Two of the most accepted are: 1. The word Earth came from the Latin Terra; and 2. The word Earth originates from the Middle English word, erthe, which came from Old English eorthe.
February 7, 2008Andrew (Canada)If the earth turns at a constant rate and revolves at a constant rate why is there so much variability in climate from place to place around the world?Many factors affect local climates (climates influencing very small geographical areas). Examples of local climates include land and sea breezes, the orographic effects of mountains and heat island effects of cities. Other factors, like pollution and desertification, are also important for local climates.
February 7, 2008aurora (USA)where are most rocks formed?what rock takes the shortest time to fully grow?do all rocks have to use a rock cycle?who found out that rocks had rock cycles?The stuff that rocks are made from has stayed the same, but the rocks themselves have not. Over time rocks are recycled into other rocks. Moving tectonic plates are the primary agents destroying and forming various types of rocks. More information in our web page What is the Rock Cycle?.
February 6, 2008emily (canada)WHat is the longest wetland?The Pantanal, an area of flooded grassland and savanna covering 200 000 square kilometers during the rainy season, is considered the largest wetland. It includes parts of Brazil, Paraguay, and Bolivia and is fed by the Rio Paraguay.
February 5, 2008Chelsea (CAlifornia)Why does the earth rotate faster than the moon?Each planet and moon rotation is unique. A full rotation of our planet about its axis, takes 23 hours, 56 minutes, 4.2 seconds (23.9345 hours). The Moon is much slower at 655.728 hours. Many factors can affect the rotational rate of a planetary body, from how much momentum the planet gained during formation to big asteroid and comet crashes that can also change rotation. An important factor is the mass of the body, Large planets are often faster than smaller ones.
February 5, 2008Raechel (Arizona, United States)My question is that what effect do droughts have on the economy?A long period of drought will affect many sides of a region economy. The agricultural activity is directly hit by a drought, but also power plants, water reservoirs for human consumption, water for cattle and other animals, etc. will be affected. Forests will dry out and will be exposed to the increased danger of raging fires with high costs, including the loss of human lifes and properties.
February 4, 2008Brantley (Western Australia)How does a magnetic field deflect solar radiation?The plasma coming from the Sun consists of charged particles that are deflected by the geomagnetic field. Some of the highest energy particles will penetrate the magnetic field, but these are less dangerous for humans.
February 4, 2008cassandra what is an example of nonsilicate group/sulfate and sulfites?An example of sulfides is pyrite, also known as "fool's gold". Gypsum is an example of sulfates. Our web page Common Nonsilicate Mineral Groups shows a table with examples of each group.
January 31, 2008Lisa (California, United States of America)I read the definition of what makes our seasons and it makes sense to me. My summer is during the summer solstice. But if I lived in Australia I would be having my winter during the summer solstice correct? Who determined the names of the solstices. Why do the names represent only half the globe?Due to the difference on the seasons, the summer solstice of one hemisphere is the winter solstice of the other. The word solstice is derived from the Latin sol (sun) and sistere (to stand still), because at the solstices, the Sun stands still in declination; that is, its apparent movement north or south comes to a standstill.
January 30, 2008Ben (Ga, USA)What does the eath's symbol stand for?An extensive description of Earth's symbol can be found here.
January 30, 2008AKSHAYA (ORISSA. INDIA)why lighting occuresDuring a thunderstorm, the Earth's surface has a + charge. Because opposites attract, the - charge at the bottom of the thunder cloud wants to link up with the + charge of the Earth's surface. Once the - charge at the bottom of the cloud gets large enough to overcome air resistance, a flow of - charge rushes toward the earth. This is known as a stepped leader. The + charges of the Earth are attracted to this stepped leader, so a flow of + charge moves into the air. When the stepped leader and the + charge from the earth meet, a strong electric current carries + charge up into the cloud. This electric current is known as the return stroke of lightning and is visible to the human eye. For more information visit our web page Lightning Formation.
January 30, 2008Laszlo (Hungary)What electric charge have the Earth's solid surface at the limit with Earth's atmosphere(positive or negative)?There is no unique value or even sign (positive or negative) for the electric charge on the earth surface. It depends upon the conditions in a particular area, for example the existence of charged clouds.
January 25, 2008kayla (tennessee)in a summer solstice where is the sun?Solstices occur twice a year, when the tilt of the Earth's axis is oriented directly towards or away from the Sun, causing the Sun to appear to reach its northernmost and southernmost extremes.In the northern hemisphere, the Summer Solstice corresponds to the longest day of the year (near June 22) when the Sun is farthest north.
January 21, 2008katrina (australia)how did the earth form???Stars and planets form as a result of the gravitational collapse of accreting material. This material was part of the solar nebula, and transferred its rotational motion to the planets, accelerating as its radius of rotation decreases.
January 15, 2008CHERISH (GEORGIA)what is the earth shell calledThe outmost layer of the solid Earth is the crust, a thin silicate rock material. Around the planet is the atmosphere.
January 15, 2008christina (minnesota, usa)if pollution in big cities such as New York, continue how will effect our enviroment?Air pollution affects visibility, human health, agriculture, and ecosystems. As cities around the world grow bigger than ever before, scientists are discovering that urban air pollution is powerful enough to affect Earth's weather and climate. In a recent (very importante) study, scientists from all over went to Mexico City for the MILAGRO (Megacity Initiative: Local and Global Research Observations) campaign. Please, visit our web page Introduction to MILAGRO for more details.
January 12, 2008rylee (Pa, USA)What igneous rock turns into limestone and then marble in the rock cycle?Please, find an extensive answer to your question The Desert Ecosystem for more information.
January 12, 2008marissa (maryland,usa)where are the tropical rainforest located?This map shows the area of tropical rainforest.
January 10, 2008abeer (ontario/canada)Are metamorphic rocks only ones that get melted back into magma? ExplainNo, all types of rocks can be melted by magma. For example, sedimentary rock can be re-melted back into the magma to become igneous rock.
January 10, 2008kevin how man volcanoes does earth haveFor volcanologists, "active" means does the volcano have the possibility of erupting again.The Smithsonian Institution uses this last definition in their web page Global Volcanism Program, and lists about 1300 active volcanoes, but these figures do not include the large number of eruptions (and undescribed volcanoes) on the deep sea floor.
January 8, 2008Noraini (Philippines)how does island arcs form?Island arcs are a arc-shaped chain of volcanic islands produced where an oceanic plate is sinking (subducting) beneath another.
January 8, 2008Autumn (charoltte)what are grasslandsGrassland are grass-dominated areas where few or no trees grow. Includes prairies and savannas.
January 8, 2008Meghan (Florida)How do clouds form over mountains?Clouds form as an air parcel rises and cools, and the water vapour content condenses when it reaches the dew point. Lenticular clouds in particular are caused by a wave wind pattern created by the mountains. They look like discs or flying saucers that form near mountains.
January 7, 2008isabelle (Autralia)is there fresh water or salted water in AntarticaMainly fresh water. Glaciers and ice caps store about 75% of the world's freshwater.
January 7, 2008manasi (Maharashtra/ India)I wantto know the temperature of the magma at the time when it spills out ? THANK YOUWhen the magma spills out is called lava. Lava temperatures during an eruption can reach up to about 1170 degrees centigrade.
January 4, 2008NETAIYAH (MISSISSIPPI)WHAT % OF EARTH IS FRESH WATERTRAPPED IN FROZEN ICECAPS AND GLACIERS?Glaciers and ice caps store about 75% of the world's freshwater.
January 2, 2008emily (georgia/north america)what is the most dangerous volcanoThe last three volcanic eruptions to cause major loss of life were Krakatoa, Indonesia, where 32,000 were killed in 1883; Mt. Pelee, Martinique, where 29,000 were killed in 1902; and Nevada del Ruiz, Colombia, where 23,000 were killed in 1985. Extracted from THE MOST DANGEROUS VOLCANO IN THE WORLD by Wiliam Menke.
January 2, 2008Eric (Michigan)What is the name of a famous spatter cone volcano? Would it be the same as a cinder cone volcano?Spatter are very fluid fragments of molten lava ejected from a vent that flatten and congeal on the ground. An example is Kilauea Volcano.
January 2, 2008Logan (victoria,australia)hey,
my question is:
If the moon stopped spining on its axis half the earth would be night all the time and half the earth would be day all the time how would this effect humanity? thank you.
I don't believe that the stopping of the moon rotation will affect the days and nights on Earth. Days and nights are due to the rotation of Earth around its axis.
January 1, 2008Forest (Colorado)What are "Goldilocks Conditions"?Our web page The Goldilocks Theory describes in details this topic. Essentially this theory states that the Earth seems to be just right for conditions favorable to life. The reasons have to do with the fact that the Earth seems to be the perfect distance from the sun for abundant liquid water.
January 1, 2008Shaanika (Namibia)what is the sole generator of magnetic field?A magnetic field can be generated from many sources and methods. But if your are asking about earth's mgnetic field, then it is generated by a so-called "dynamo". This page has a nice description of the process.
December 27, 2007BELINDA (AL;DECATUR)IS THER ANY EVIDENCE ON THE GLOBE THAT THE EARTH'S SURFACE AND ATMSHERE ARE ACTIVE ?IF SO DESCRIBE IT.Just one example for each one: earthquakes (surface) and hurricanes (atmosphere).
December 26, 2007Kathy (Florida USA)Could the magnetic field have changed when the planets were placed in the solar system, which would have caused a great change in the magnetic pull, thus giving us a fingerprint for creation and showing which planets were placed in our solar system by a certain order, based on the pull (time difference)?The planets with a recordable magnetic field are quite different among them. The magnetic fields have different characteristics, different interactions with the solar wind, different orientation, etc. It would be hard to compare them to obtain their time life.
December 26, 2007Teresa (California San Francisco)In the future, will there be no North or South Pole because of global warming?South Pole has solid ground under the ice, but this is not the case for the North Pole. Now, we don't kow for certain if the whole polar ice sheet will be melted.
December 21, 2007Keila (PA)Why is the equator a fixed position on the globe while the Prime Meridian could be placed anywhere on the globe?The North and South hemispheres, divided by the equator, have very distinct seasons along the year, while nothing similar happens to East and West hemisphere, as delimited by the Prime Meridian.
December 19, 2007laura (australia NSW)diagrams of tsunamis caused by earthquakesThis page has a good animated diagram.
December 17, 2007Mili (Gujarat,India.)What might be the consequences if Earth's core cools down like the crust?One of the immediate consequences would be the weakening of the magnetic field that surrounds and protects our planet.
December 10, 2007 on the magnetosphere page there is a distance from earth which is given, but is that distance from the surface or the center of the earth?The distances to the magnetosphere boundaries are usually expressed from the center of our planet.
November 7, 2007tai (new zealand)how many feet is mount vesuvius ?The elevation of Mount Vesuvius is 1,281 M (4,203 FT).
October 16, 2007Ronnel (Philippines)What is nitrogen cycle?Nitrogen is an element. It is found in living things like plants and animals. It is also an important part of non-living things like the air above and the dirt below. Atoms of nitrogen don't just stay in one place. They move slowly between living things, dead things, the air, soil and water. These movements are called the nitrogen cycle. More information in our web page Nitrogen Cycle.
October 16, 2007Ronnel (Philippines)What are the segnificance of carbon cycle?Next is only a way to look at this issue, for more information, visit our web page Carbon Cycle. Carbon moves through our planet over longer time scales. For example, over millions of years weathering of rocks on land may add carbon to surface water which eventually runs off to the ocean. Chemical weathering of silicate minerals, in particular, can have an effect on the amount of carbon dioxide in the atmosphere. Additionally, over long time scales, carbon is removed from seawater when the shells and bones of marine animals and plankton collect on the sea floor. These shells and bones are made of limestone, which contains carbon. When they are deposited on the sea floor, carbon is stored from the rest of the carbon cycle for some amount of time. The amount of limestone deposited in the ocean depends somewhat on the amount of warm, tropical, shallow oceans on the planet because this is where prolific limestone-producing organisms such as corals live. The carbon can be released back to the atmosphere if the limestone melts or is metamorphosed in a subduction zone.
October 16, 2007Matthew (California,united states)if the mesosphere is the coldest then how can meteors get burned?Meteors get burned due to the friction with the air, and not because of the temperature.
October 16, 2007gayle (philippines)what are the layers of waterOur web page The deep Waters of the Ocean offers an extensive information on this topic.
September 19, 2007Erin (Iowa, USA)What would happen in the sun would shine only one day per month?We will only get 12 days of sunshine. It is safe to expect a catastrophic cooling of the planet.
September 19, 2007Cathy (Akron, OH)Why don't we have any physical sensation of movement as the earth spins on its axis and orbits the sun?From a Newtonian point of view we are at rest with respect to the planet. Due to the lack of a close enough point of reference, we can't see or feel the motion.
September 12, 2007Roxy (Florida)What is the mass of one cubic meter of continental and/or oc eanic crust?The density of continental crust is about 2.7 g/cm³ (grams per cubic centimeter) or 2 700 kg/m³ (kilogram per cubic meter). The average density of the oceanic crust is 3 g/cm³ = 3 000 kg/m³.
September 12, 2007mae (philippines)what is doforestation?Deforestation is the permanent destruction of indigenous forests and woodlands. Deforestation has resulted in the reduction of indigenous forests to four-fifths of their pre-agricultural area.
September 12, 2007rhamae (Philippines)what is rock cycleAll rock (except for meteorites!) that is on Earth today is made of the same stuff as the rocks that dinosaurs and other ancient life forms walked, crawled or swam over. While the stuff that rocks are made from stays the same, the rocks do not. Over millions of years, rocks are recycled into other rocks. Moving tectonic plates help to destroy and form many types of rocks. Please, visit our webpage Rock and the Rock Cycle for more information.
September 12, 2007Andrew (Australia)Are there any instruments on the moon to measure temp? and if so has the moons temp increased?Although the tripulation of Apollo 16 took pictures and performed research tasks that included use of an ultraviolet camera/spectrograph - the first astronomical and Earth observations taken from the Moon's surface in 1972, currently there are not instruments on the Moon. However, more recently, a NASA Advisory Council subcommittee has taken on the task to consider the use of Moon-based instruments to study the Earth.
September 11, 2007alexandra (america/florida)What physical factors and positions, or movements, of the earth cause different amounts of energy to strike the surface of the earth?The different amounts of solar energy that reach different areas of our planet is mainly due to the tilt of the Earth's axis. In other words, the tilt of Earth's rotational axis and the Earth's orbit work together to create the seasons. Please, visit our webpage Earth's Seasons for more information.
September 4, 2007guadalupe (nevada)Is it true tha if people dont stop using hair spray the amospher will pop and we will die burningThe CFCs (Chloro-Fluoro-Carbons) were used in air conditioners, spray cans (including hair sprays) and foam materials. Their use has been regularly prohibited by the Montreal Protocol, because of effects on the ozone layer and because they also are a powerful greenhouse gas.
August 21, 2007David (ENGLAND)Is the earths gravitational pull (escape velocity) less at the equator than at the poles - due to its rotation causing a centrifugal force.
The centrifugal force would be greater at the equator compared to the poles ?
Yes, the centrifugal force is greater at the equator and hence the gravitational force is lower.
August 17, 2007kenneth (philippines)what is a water cycle? please help me because i need to explain this to my teacher.The Earth's water is always in circulation. It has been recycled for the last 3 billion years. This process is called the water cycle. The cycle starts when the sun's heat evaporates water from the oceans into the atmosphere to form clouds. When the conditions are just right, the clouds release water as rain or snow. Most of the rain falls in the oceans, but the rest falls onto land. Rivers and streams collect water from the ground and return it to the ocean so the whole cycle can start all over again. The water cycle never ends because the salty ocean water constantly supplies fresh water to the continents. More information in our web page Water Cycle and the links therein.
August 17, 2007vibhav (u.p./ India)why is the axis of Earth tilted?All the planets have axial tilts. The predominant theory is that this occured due to collisions in their formative phase.
August 17, 2007jai (india)why we do not rotate with earth?We do!!!! Because we are fixed to the surface we don't notice this rotation, but there are several ways to prove it, including the motion of the sun and stars in the sky.
July 23, 2007nori (united states)what is magnetic earthI am not sure what you meant by "magnetic earth". Our planet, and many others, generates a magnetic field. This field is roughly similar to a bar dipole magnetic field. The solar wind interacts with this field to produce, under the right conditions, the beautiful auroras.
July 21, 2007Phil (California)What affect would the presence of two or three moons have on the earth?For starters, a way more complicated tide system (due to a more complex gravitational pull), more partial and total Sun and moon eclipses, and a more beautiful sky!
July 21, 2007Faith (Florida, USA)Where is the closest lithospheric plate to us here in Florida? What type of boundary is it and what types of processes occur there?Florida is on the North American plate, near the Caribbean plate. This two plates have a transform boundary. This type of boundary occurs when tectonic plates slide and grind against each other along a transform fault.
July 21, 2007elizabeth (Philippines)How does the air affects the movement of the earth?Our web page Can Earth’s Spin Be Changed by Wind? answer your question in detail.
July 20, 2007Glen (Auckland, New Zealand)When half the world is facing away from the Sun, why does it not completely freeze?Because all bodies have a property known as "heat capacity" (ability of a body to store heat as it changes in temperature). The heat stored is slowly release during the night, keeping a more or less uniform temperature in our planet.
July 20, 2007lionel (alalbam/usa)in what countries does the sun shine 24 hours on the longest day of the year?Sunrise and sunset at the poles take a long time. At the poles, the Sun does not go higher and lower in the sky each 24-hour day, but goes very slowly up in the spring or down in the summer. During a 24-hour period, the Sun goes all the way around the sky at almost the same height. More information at Astronomy Answers.
July 20, 2007Elizabeth (New Zealand)How far is the sun from earth?Due to the excentricity of the orbit of our planet, the distance to the Sun change along the year. The Minimum Distance from Sun is 146 million km (91 million miles), and the Maximum Distance from Sun is 152 million km (94.5 million miles).
July 20, 2007reg (canada)what are the longest and shortess days of the year in ontario canadaIn the Northern Hemisphere the summer solstice (June 21 this year) is the longest day in the year, and the winter solstice (December 22 this year) is the shortest day (and longest night) of the year.
July 19, 2007Brahmani (Hyderabad)WHY WE SAY EARTH AS PLANET?There are many definitions of planet, all of them with certain degree of ambiguity, one of them is: A spherical object orbiting a star that is not a brown dwarf but is bigger than an asteroid. Our plane fulfills this definition.
July 18, 2007ritu (mumbai,india)will earth be over because of global warming, can nothing be done what we all can afford to do?I believe humanity is right now at a crucial point of its history. Many efforts are already in place, and most importantly, normal people, like you and me, are realizing the seriousness of the situation. Now it is in hands of politicians and corporations to do their part, and we should let them know so.
July 18, 2007shana (south Australia)does the distance from the sun infulence the climate and temperture of a coutry ver much?Not really, the distance to the Sun is roughly the same for all the planets. An important factor for climate and temperature is the latitude of the country. At higher latitudes (closer to the poles) the angle of incidence of the Sun rays is lower, and because that the mean temperature of the region will be lower.
July 18, 2007bhoomika (india)why are volcanoes formed?Volcanoes form when hot material from below rises and leaks into the crust. Our web page Volcano formation offers more information.
July 18, 2007Richard (Wisconsin USA)Is it possible that the oceans floor was once land and it flooded somehow and new land has formed from volcanos??This activity from the U.S. GEOLOGICAL SURVEY describes in a very clear way the processes related with sea-floor spreading.
July 18, 2007MANIK (INDIA)HOW LONG WILL EARTH LIVE.The answer to your question is still open. What we know is that a star with a mass similar to that of our Sun and in the last phase of its life is a red giant. Hydrogen fusion reactions have become less efficient in the core region, and the fusion reactions now occur in a shell surrounding the core. The outer layers then cool to about 3000 K and becomes a red star of a huge size, reaching the orbits of all the interior planets.
July 17, 2007Danaca (America)How long do you think it will be until Global Warming comes to affect and kills us all, if ever?Our planet is already suffering the effects of the global warming. We have several page in our website that are related to this issue: -- Melting Arctic Sea Ice and the Global Ocean Conveyor -- The Cryosphere and Global Climate Change -- Climate and Global Change News -- Warming of the Polar Regions -- Warming of the Polar Regions The links therein will offer additional information.
July 17, 2007Monae (New Jersey)How do a tornado form?A tornado begins in a severe thunderstorm called a supercell. A supercell can last longer than a regular thunderstorm. The same property that keeps the storm going also produces most tornadoes. The wind coming into the storm starts to swirl and forms a funnel. The air in the funnel spins faster and faster and creates a very low pressure area which sucks more air (and possibly objects) into it. More information in our web page How a Tornado Forms.
July 17, 2007Cherika (Washington/ USA)What is the significance of the SAL (Sahara air layer) to the development of a hurricane?This NOAA press release should answer your question.
July 17, 2007Emily (Lake Forest, Ca)I would like to know the fossils are trapped in the rocks, and how are the rocks formed three ways?The rocks are classified in three groups: Igneous rocks: formed from the cooling and solidification of magma. Sedimentary rocks: formed at the surface of the Earth from the accumulation of sediments (fragments of rocks, minerals, or animal or plant material) Metamorphic rocks: formed within the Earth's crust when other rocks are subjected to pressures or heat so intense that they are completely changed. For more information visit our page Rocks and the Rock Cycle.
July 17, 2007Sanjana (New Delhi,India)please can you tell me the types of forest ecosystem( is it right to put TAIGA under forest ecosystem)?Yes, taiga is a forest ecosystem.
July 17, 2007tyler (california/us)What kind of a eruption does a cinder cone volcano have?As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as cinders around the vent to form a circular or oval cone.
July 17, 2007Daniel (maryland)what causes the sun to appear red during sunrisesThe Sun looks red during a sunset because of Earth's Atmosphere. When the Sun goes down, we see it through gases and dust that are in the sky. The color it appears to be depends on what is in the air. If you see red, it is because all the other colors are being absorbed by the particles, but the color red is being reflected.
July 17, 2007Bea (Munich)I have to do a report on Global warming, and I was wondering where to find some information. Do you have any links, or some facts about Global Warming? What is Global warming generally?We have several page in our website that are related to this issue: -- Melting Arctic Sea Ice and the Global Ocean Conveyor -- The Cryosphere and Global Climate Change -- Climate and Global Change News -- Warming of the Polar Regions -- Warming of the Polar Regions The links therein will offer additional information.
July 11, 2007Ana (California)What causes the difference in the Northern and Southern hemispere wind?There are different seasons to take in account.
July 10, 2007Greggory (AR, USA)Are there "holes" at the Earth's poles? I thought the idea was crazy until I was unable to get clear, detailed polar photos. Is there something there our government and the scientific community is hiding?As a part of that scientific community I can assure you that there is nothing to hide. The poles are critical elements of our planet climate, and right now they are the main objective of a global effort: the International Polar Year (IPY). Our webpage International Polar Year - and IPY's of the Past also offers information on this topic.
July 10, 2007rachel (asia)how are fold mountain form?Fold mountains are formed when two plates move together. The movement of the two plates forces sedimentary rocks upwards into a series of folds. As a curiosity, visit this webpage for a very different type of "fold mountain".
July 9, 2007Kenneth (Florida, USA)How is called the movement of water from air to Earth and back again? (2 words)What you are describing is part of the Water Cycle.
July 9, 2007Vijay What will happen if sun does not rise on earthThat would mean that our planet is not moving any more around the Sun, and all things related with these motions will stop. For example, we wouln't have days and nights or seasons!
July 9, 2007j (rosevill)what is a autumnal equinox and a spring quinoxThe spring and autumn equinoxes occur around March and September 21. These are special points in the Earth's orbit when the Sun appears directly above the Earth's equator. Day and night are the same length, about 12 hours. For more information, visit our webpage The Spring and Autumn Equinoxes.
July 6, 2007Kaitlyn (Ohio)Can you explain why and how the moon's gravity can cause the oceanic tides?Due to the mutual gravitational atraction between the Earth and its moon, there are forces acting over both. In the case of our planet, the only element that can be moved is liquid, and the bigger bodies of water show the effects of this atraction in the form of tides.
July 5, 2007Michelle (Denver Colorado)Where doesmost fo the rain/precipition fall in Colorado?In general, most of the precipitation fall on the mountains. For a more detailed answer to your question go to this webpage of the Colorado State University. This map is particularly informative.
July 3, 2007Bobby (Florida United States)Where is Calcite found?Calcite is typically found in the sedimentary rock called limestone. Calcite is also in marble, a metamorphic rock, which forms when limestone is put under strong heat and pressure. More information in our webpage Calcite.
July 3, 2007Nikki (Ohio USA)About how much of the world is covered in grasslands/savannasGrasslands/savannas are one of the Earth's major ecosystems. The estimates of the amount of the Earth's land surface covered by them vary considerably, but almost all scientists consider a minimum of 15%.
June 28, 2007amanda (kansas)what is a convergent boundryIn plate tectonics, a convergent boundary is an actively deforming region where two (or more) tectonic plates or fragments of lithosphere move towards one another.
June 28, 2007Charis (Arizona, U.S.)How big is Earth i miles?The diameter of our planet is 12 753 km = 7,926 miles.
May 30, 2007chelsea (ny)what is the eye of a hurricaneThe eye is the calmest part of a hurricane. Surrounding the eye is the eye wall, which is the most violent part of a hurricane. The eye wall is almost a complete ring of thunderstorms and contains the strongest winds in the hurricane. More information in our web page Eyes and Eye Walls of the Hurricane.
May 21, 2007Megz (Wales)What is the form of weathering effect called that could split open a piece of rock when water freezes into ice?There are two main classifications of weathering: Mechanical weathering (involves the breakdown of rocks and soils through direct contact with atmospheric conditions such as heat, water, ice and pressure), and Chemical weathering (involves the direct effect of atmospheric chemicals), in the breakdown of rocks, soils and minerals.
May 21, 2007Tyasia (florida)how was earth formed and how and when was earth discoveredScientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star (called a supernova). This explosion made waves in space which squeezed the cloud of gas and dust. Squeezing made the cloud start to collapse, as gravity pulled the gas and dust together, forming a solar nebula. Just like a dancer that spins faster as she pulls in her arms, the cloud began to spin as it collapsed. Eventually, the cloud grew hotter and denser in the center, with a disk of gas and dust surrounding it that was hot in the center but cool at the edges. The planets and moons were formed from this solar nebula. For a description of the formation of our system, please visit our web page Solar System Formation.
May 21, 2007Liam how does thunderstorms formIn a calm sky, the positive (+) and negative (-) charges are evenly distributed and so the calm sky has a neutral charge. Inside a thunderstorm, electric charge is divided, with + charge at the top and - charge at the bottom. Under these conditions, the ground has + charge, and because opposite charges are attracted, .the - charge at the bottom of the thunderstorm cloud wants to meet the + charge of the ground. The jump of the charges happens so fast that all we can see is a line of light. This is called lightning. More information on this topic can be found in our page Lightning Formation.
May 11, 2007Valentina (Bogota, Colombia)Does the pressure of the plates affect the height of the tsunami?The magnitude of the disturbance causing the tsunami is the primary factor influencing the size and strength of the waves. Tsunamis are most often triggered by earthquakes, but they can also be produced by landslides, volcanic eruptions, explosions and the impact of meteorites or asteroids.
May 10, 2007Maricela (CA)Is MountSt.Helens a Composite VolcanoMount St. Helens is a composite cone (has erupted both lava flows and ash flows).
May 7, 2007may (teaxes)a metamorphic rock that has visble layers or bands.Foliated metamorphic rocks have visible layers or bands.
May 7, 2007samantha (fl/usa)how many moons dose the earth have.Just one, our beautiful Moon!
May 5, 2007Yashna (Chandigarh)What are meteorites?A meteorite is a relatively small extra-terrestrial body that reaches the Earth's surface. While in space these bodies are called meteoroids and are called meteors after entering Earth's atmosphere, but before reaching the surface. These are "small" asteroids, approximately boulder-sized or less. Upon entering the atmosphere, air drag and friction cause the body to heat up and emit light, thus forming a fireball or shooting star. More information on our web page Meteors. Definition from Wiki/Meteorites.
May 5, 2007Sarah (New York, United States of America)Will there ever be a super tsunami?A super- or mega-tsunami could happen under specific conditions. The collapse of the volcano Cumbre Vieja in the island of La Palma, in the Canary Islands in the Atlantic Ocean, has been mentioned as one of the possible causes for a mega-tsunami. The impact of a meteorite os a considerable size could also create a mega-tsunami.
May 5, 2007Antonella (Costa Rica)What percentage of the earth is covered by ice?Almost 10 percent of the world's land mass is currently covered with glaciers, mostly in places like Greenland and Antarctica.
May 5, 2007Antonella (Costa Rica)What area (m2 or km2) does the current area covered by ice in north pole and the south pole have?The sea ice extent in the Nothern Hemisphere in March 2006 covered an area of 14.5 million square kilometers, in September 2006 covered an area of 5.9 million square kilometers. (seasonal minimum and maximum). The corresponding values in the Southern Hemisphere were 2.7 million square kilometers for February 206, and 19.3 million square kilometers during September 2006.
April 19, 2007Karleena could you please send me some information on the atmosphere.Our web page The Earth's Atmosphere , and the links therein, provide a significant amount of information about our planet atmosphere.
April 19, 2007Casi (florida us)If i weight 75 pounds on earth. What would I weigh on mars?Our planet gravity (at sea level) is 9.8 m/s2. Mars surface gravity is 3.7 m/s2 (0.37 x Earth's). So, your weight there will be 75 lbs x 0.37 = 27.8 lbs.
April 19, 2007stephanie (Texas United States)when will the earth end and what will happened when it does?In about 5 billion years, the hydrogen in the center of the Sun will start to run out, the helium will get squeezed, and this will speed up the hydrogen burning. Our star will slowly puff into a red giant and will eventually eat all of the inner planets, even the Earth.
April 19, 2007Christian (Western Australia)If the moon rotates so that the near side always faces the earth, and the orbits of the moon and earth are such that a full moon appears when the sun and moon are on opposite sides the earth and a new moon appears when the moon sits between the sun and the earth, how can there be a dark side of the moon. I.e. With a full moon, the sun shines on the near side and reflects directly back to earth. With a new moon, the near side is in shadow and therefore the far side must be illumunated. If the near side is a constant face to us, how can there be a dark side if that face is in sunlight during a full moon and in darkness during a new moon?You are absolutely right, there is not a dark side of the Moon!!! Only a side that we can't see from Earth.
April 19, 2007Jeni (Ontario Canada)Is it possible for the earths rotation to be altered? I have read that some "wobbles" in our rotation have been linked to earthquakes. (reported in 2003)NASA scientists using data from the Indonesian earthquake calculated it affected Earth's rotation, decreased the length of day, slightly changed the planet's shape, and shifted the North Pole by centimeters. The earthquake that created the huge tsunami also changed the Earth's rotation. Read the full article here.
April 19, 2007carolina (united states)Could the early atmosphere support life as we know it?As the pre-Cambrian era came to a close, and oxygen levels in the early atmosphere began to approach 1% of what they are today, more and more advanced life forms began to appear. Rather than a single cell, life forms now were multi-cellular.
April 19, 2007Jo (Kansas)when the poles reverse, does the magnetosphere disappear? If so, does the solar wind reach the earth's surface?During the reversal the magnetosphere would become very unstable, week, and complex, but it wouldn't disappear. Under these conditions it is very likely that the solar protons will easily reach the atmosphere, but there won't be any significant change on the ground level because the continuous protection of our atmosphere.
April 7, 2007Kayla (West Liberty)Why is the crust important, or what is its there for?While the crust is very thin in comparison to the other three layers (only about 8 km, 3-5 miles thick under the oceans and about 32 km, 25 miles thick under the continents, it is the layer where we lived!
April 7, 2007Storm (Australia)Why does the moon exist?There are three theories about how the moon came to be in place: - that the moon came out of the crust of the Earth - that the moon was captured by the Earth - that the Earth and moon formed together out of the primordial nebula.
April 4, 2007jada (georgia)Where can you find the Auroras?(on earth)The auroras are commonly seen around the polar regions. At times, under very disturbed geomagnetic conditions, these beautifull lights can be seen at lower latitudes.
April 4, 2007jada (georgia)What are the Auroras?The auroras are a luminous atmospheric phenomenon that generally appear as bright colorful bands of light. They are commonly seen around the polar regions. At times, under very disturbed geomagnetic conditions, these beautifull lights can be seen at lower latitudes. Our page The Aurora offers more information, links, and pictures of auroras.
March 31, 2007sally (canada,nova scotia)is it true that if the planets move, not orbit, they wo uld explode?A planet, to be considered as such, "has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape" (extracted from the definition of planet by the International Astronomical Union). This means that planets' shape are obtained from their own mass, not from external factors. Of course, if a planet is moving outside the gravitational field of a star, it is not a planet, because it fails to fullfill the first condition of the definition of planets: "is in orbit around the Sun".
March 31, 2007ryan (idaho)How are the Earth and Moon similar?The interior of the Moon is very similar to the interior of our planet: an iron rich core, a plastic asthenosphere, a thick mantle, and finally a thin crust.
March 27, 2007Rogina (Anderson,Texas)What is the diameter of Earth?Earth's diameter is 12 753 km (7,926 miles). For more interesting planetary facts, visit our web page Earth Statistics.
March 26, 2007aiden (IN, USA)Why does the North end of a compass always point North? I thought that like charges repel.Exactly! The same rule of "opposites attract" is at work here. The colored part of the compass needle that will point to the North is the South pole of the magnetized needle. To be accurate, the Earth magnetic poles are not exactly at the same spots as the geographic poles, the magnetic north pole is around 1 400 miles away from the geographic north pole.
March 23, 2007RADHIKA (DELHI/INDIA)What kind of life existed exactly 3000 years ago/The life on our planet has not suffered drastic changes in the last 3 000 years. Humans were already roaming, and most of the animals and plants were basically the same. To have a better idea of the changes suffered by our planet, visit our web page Geologic Time.
March 23, 2007Belen (Florida/United States of America)Where does the energy from Earth's core come from?Our planet's core is hot because of radioactive heating. The core is full of radioactive elements producing heat as they decay.
March 23, 2007Jessica (ny)how do rocks change spots within the rock cycle?The rock cycle transforms rocks from one type to other, and, with these transformations, moves then around. More information can be found in our web page Rock Cycle and the links therein.
March 20, 2007Beck (U.K.)How deep is the Earth from surface to centre?The radius of the Earth is measured from the center of the Earth to the sea level at a given point. This value is at the equator 6 378.135 km.
March 5, 2007 How does moving West of New York City, by a significant distance of at least 200km effect the hours of sunrise and sunset, ie the length of days.When moving to the west, we will see a later sunrise, and a same time amount of a later sunset, so the length of the day stays the same! However, different seasons do change the length of the day (equally for all longitudes)
February 24, 2007denise (california/united states)how do metamorphic rocks form?Metamorphic rocks are formed within the Earth's crust when other rocks are subjected to pressures or heat so intense that they are completely changed.
February 24, 2007meg (W.A)at what angleis the earth tilied.The tilt of our planet's axis is 23 degrees 27minutes. More interesting facts are at our web page Earth Statistics.
February 22, 2007omar (egypt)what is in the space junk ?Whether on Earth or in Space, human activity creates waste. Like the Earth's environment, the space environment is getting more and more cluttered. There are currently millions of man-made ruins that make up "space junk". Unfortunately, the past 30 years of space exploration have generated a lot of junk that poses a significant threat to spacecraft now in orbit. Orbital debris includes things such as hatches blown off space modules, paint fragments from the space shuttle, or satellites that are no longer in use. For more information, visit our page Junk in Space!.
February 13, 2007saar (uttar pradesh)why r the earth a planet? what is the area of earth?Earth is a planet because it fulfills the definition of planet by the International Astronomical Union (IAU): A planet is a celestial body that - is in orbit around the Sun, - has sufficient mass for its self-gravity to overcome rigid body forces, and - has cleared the neighborhood around its orbit.
February 12, 2007Keisha (Tenneessee)What is the streak of feldsparFeldspar is the most common mineral in the Earth’s crust, so you are very likely to find traces of it (streaks) in the rocks you collect! Please, visit our web page Feldspar for more information.
February 12, 2007Kayla (Missouri)how does the moon orbit the earth?There are three theories about how the moon came to be in place: - that the moon came out of the crust of the Earth - that the moon was captured by the Earth - that the Earth and moon formed together out of the primordial nebula In all cases, the Moon is trapped by our planet gravitatory field.
February 5, 2007ayaka (honolulu, hawaii)how big in killometers is earth?Our planet has a diameter of 12 753 km, and a mass = 5.98x10^24 kilograms. More of Earth's planetary facts at Earth Statistics.
January 29, 2007natalie (uk)at what lattitude are day and night the same lengths all year round?If you live in a place that is far from the equator, you may have noticed that during winter there are fewer hours of sunlight than during summer. This is because of the tilt of Earth’s axis. Earth's tilt is the reason for the seasons. The closer you are to one of Earth’s poles, the less sunlight there is during winter days. At the Arctic and Antarctic Circles there is one full day when the Sun does not set and one day when it does not rise. The Sun does not set on the summer solstice (June 21 in the north and December 21 in the south) and does not rise on the winter solstice (December 21 for the north and June 21 for the south). In the weeks prior to the winter solstice, the number of hours with sunlight become fewer and fewer until on the winter solstice when the Sun does not rise at all for a day. After the winter solstice the amount of daylight increases each day until the summer solstice when the Sun does not set at all for one day. For more information, visit our web page Geography of Earth's Polar Regions.
January 29, 2007Bob (Massachusetts / USA)What is the Circumference of the earth ?The circumference of the Earth is 24,901.55 miles (40 075.16 km) at the equator. If we were measuring around the poles, the circumference would be a bit shorter. Much more information about our planet can be found at our web site Earth Numbers and Earth.
January 25, 2007Jordan (Florida/ united states)How is the ocean floor mapped?There are several methods to map the sea floor. For example, the U.S. Geological Survey describes a recent sea floor mapping: "The sea floor of the Stellwagen Bank National Marine Sanctuary was surveyed by using a multibeam sea-floor mapping system that utilized sound to measure the water depth and sediment characteristics as the ship steamed over the area of interest. This system provided a new and highly detailed view of the sea floor at a spatial resolution of a few meters. During the survey, the mapping system was mounted on the Canadian Hydrographic Service ship Frederick G Creed, a small waterplane twin hull (SWATH) vessel specially designed and equipped for multibeam surveying. Guided by these detailed images, we are using extensive bottom sampling and video and photographic observations to define and map biological habitats."
January 25, 2007tony (oakland)what makes the seasons of earthThe tilt of Earth's rotational axis and the Earth's orbit work together to create the seasons. As the Earth travels around the Sun, it remains tipped in the same direction, towards the star Polaris. This means that sometimes the northern half of the Earth is pointing towards the Sun (summer), and sometimes it is pointing away (winter). These points in the Earth's orbit are called solstices. Notice that when the northern hemisphere is tilted towards the Sun, the southern hemisphere is tilted away. This explains why the hemispheres have opposite seasons.
January 23, 2007Josh (Indiana/ United States Of America)How does an Igneous rock change to a Metemorphic rock?The rocks are classified in three groups: Igneous rocks: formed from the cooling and solidification of magma. Sedimentary rocks: formed at the surface of the Earth from the accumulation of sediments (fragments of rocks, minerals, or animal or plant material) Metamorphic rocks: formed within the Earth's crust when other rocks (including igneous rocks!) are subjected to pressures or heat so intense that they are completely changed. For more information visit our page Rock Cycle.
January 22, 2007joni (london, england)can you tell me what is the biggest the sun, moon or the earthThe Sun is, by far, the biggest body in our solar system. Earth is bigger than its moon.
January 22, 2007Heather (IN/U.S.)tell me how a sedimentray rocks,and how they form.For thousands, even millions of years, little pieces of our earth have been eroded--broken down and worn away. Sedimentary rocks form at the surface in environments such as beaches, rivers, the ocean, and anywhere that sand, mud, and other types of sediment (those little pieces) collect. They make up about three-quarters of the rocks at the Earth’s surface. They Sedimentary rocks preserve a record of the environments that existed when they formed. For more information visit our page What Is a Sedimentary Rock?.
January 21, 2007Joy (Florida U.S.A)When plates run into each other and buckle, what happens?The potential energy stored in the system increases, and at certain point is liberated as earthquakes.
January 21, 2007adam (washington)how is our moon's formation suposed to have been different then the formation of other planetary satelites?In general, scientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star (called a supernova). This explosion made waves in space which squeezed the cloud of gas and dust. Squeezing made the cloud start to collapse, as gravity pulled the gas and dust together, forming a solar nebula. The planets and moons were formed from this solar nebula. For a description of the formation of our system, please visit our web page Solar System Formation. In the particular case of our Moon, there are three theories, more or less related to the previous description, about how the moon came to be in place: - that the moon came out of the crust of the Earth - that the moon was captured by the Earth - that the Earth and moon formed together out of the primordial nebula
January 19, 2007Sam (California)What are the interior layers of Our Moon composed of ?(kind of minerals/rocks)The structure of the Moon's interior is difficult to study. The Moon's top layer is a rocky solid, perhaps 800 km thick. Beneath this layer is a partially molten zone. Although it is not known for certain, many lunar geologists believe the Moon may have a small iron core, even though the Moon has no magnetic field. By studying the Moon's surface and interior, geologists can learn about the Moon's geological history and its formation. For more information, please visit our page The Earth's Moon.
January 17, 2007Rosalinda (CA - USA)Do you know of any other (aside from Apollo 8) space flight that reached teh escape velocity FOR Earth?All missions going in to deep space (to study other planets, for example) need to reach the escape velocity for our planet.
January 17, 2007Graciela (Arizona)How did the moon formedThere are three theories about how the moon came to be in place: - that the moon came out of the crust of the Earth - that the moon was captured by the Earth - that the Earth and moon formed together out of the primordial nebula
January 16, 2007tiana (macon)why is lonosphere not on hereWe have discussed the ionosphere in several of our pages: The Ionosphere, The Sun's Effect on the Ionosphere, Regions of the Ionosphere, Ionosphere Constituents, etc.
January 14, 2007Diana (Queensland-Australia)What other types of cyclones are there apart from the tropical cyclone?The six major types of cyclones are: Polar cyclone, Polar low, Extratropical, Subtropical, Tropical, or Mesoscale. Tropical cyclones, in particular, are also known, depending on their location and strength, as hurricane, typhoon, tropical storm, cyclonic storm and tropical depression.
January 14, 2007aivy (philippines)is ionosphere important to our atmosphere?The ionosphere, as the electrically charged portion of our atmosphere, is responsible for the changes that electromagnetic waves suffer when traveling through it. For example, before the first communication satellite reached orbit, we were able to communicate via radio with Europe through bouncing radio signal against the ionosphere. Similarly, the Global Position System (GPS) signals are affected when passing through the ionosphere.
January 3, 2007Eduardo (Philippines)What is the meaning of Foliated Rocks and please give its usesThe layering within metamorphic rocks is called foliation and it occurs when a strong compressive force is applied from one direction to a recrystallizing rock. This causes the platy or elongated crystals of minerals, such as mica and chlorite, to grow with their long axes perpendicular to the direction of the force. This results in a banded, or foliated, rock, with the bands showing the colours of the minerals that formed them. Textures are separated into foliated and non-foliated categories. Foliated rock is a product of differential stress that deforms the rock in one plane, sometimes creating a plane of cleavage: for example, slate is a foliated metamorphic rock, originating from shale. Non-foliated rock does not have planar patterns of stress. For a comprehensive discussion on this topic, visit the Wikipedia web page Metamorphic Rocks.
December 27, 2006bethany (NewYork)How did earth cometo beScientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star (called a supernova). This explosion made waves in space which squeezed the cloud of gas and dust. Squeezing made the cloud start to collapse, as gravity pulled the gas and dust together, forming a solar nebula. The planets and moons were formed from this solar nebula. For a description of the formation of our system, please visit our web page Solar System Formation.
December 27, 2006Elise (G.A)How Far Away Is The Moon From The Sun?Because the our Mon rotates around the earth, we can use our planet distance to the Sun: Minimum Distance from Sun: 146 million km (91 million miles) Maximum Distance from Sun: 152 million km (94.5 million miles)
December 27, 2006Ashley (plant city)how do scientists think earth formed.Scientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star (called a supernova). This explosion made waves in space which squeezed the cloud of gas and dust. Squeezing made the cloud start to collapse, as gravity pulled the gas and dust together, forming a solar nebula. The planets and moons were formed from this solar nebula. For a description of the formation of our system, please visit our web page Solar System Formation.
December 20, 2006krishnadas (kerala/india)"I have heard that moon has a low gravitational force .Even then it is capable of attracting the Earth.Please tell me how."The Earth's natural satellite, the Moon, is more than one quarter the size of Earth itself (3,474 km diameter). Because of its smaller size, the Moon's gravity is one-sixth of the Earth's gravity. More interesting facts about the Moon can be found in our web page The Earth's Moon.
December 20, 2006jodecy (florida)What is metamorphic rockThe rocks are classified in three groups: Igneous rocks: formed from the cooling and solidification of magma. Sedimentary rocks: formed at the surface of the Earth from the accumulation of sediments (fragments of rocks, minerals, or animal or plant material) Metamorphic rocks: formed within the Earth's crust when other rocks are subjected to pressures or heat so intense that they are completely changed. For more information about Rock and the Rock Cycle visit our page Rocks.
December 20, 2006Cody (New Jersey/USA)Why are meteor craters more common on the moon than on the Earth?Because on Earth, due to the existence of the atmosphere, most asteroids vaporize before they can reach the surface.
December 20, 2006Josie (Washington, United States)Why are there more meteorite landings on the moon then the earth when the earth is bigger then the moon?Because on Earth, due to the existence of the atmosphere, most asteroids vaporize before they can reach the surface.
December 20, 2006kendrea (Geogetown)what is the ozone layerThe ozone layer is the part of the Earth's atmosphere which contains relatively high concentrations of ozone (O3). It was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson.
December 14, 2006hayli (Tennessee)What is the lithosphere and the asthenosphere made of?Together the crust and upper mantle are called the lithosphere and they extend about 80 km deep. The lithosphere is broken into giant plates that fit around the globe like puzzle pieces. These puzzle pieces move a little bit each year as they slide on top of a somewhat fluid part of the mantle called the asthenosphere. The asthenosphere is solid even though it is at very hot temperatures of about 1600 C due to the high pressures from above. However, at this temperature, minerals are almost ready to melt and they become ductile and can be pushed and deformed like silly putty in response to the warmth of the Earth. These rocks actually flow, moving in response to the stresses placed upon them by the churning motions of the deep interior of the Earth. The flowing asthenosphere carries the lithosphere of the Earth, including the continents, on its back.
December 14, 2006D (Nassau,Bahamas)What is the solid part of the earth called?It is called the lithosphere (from the Greek for "rocky" sphere).
December 13, 2006mackenzie (maine usa)What is the second brightest object in earths skys?It is the Moon (the first is the Sun).
December 13, 2006nursel (florida)What are the ways a volcano can be formed?Volcanoes form when hot material from below, called magma and gathered in a magma chamber, rises and leaks into the crust. For more interesting information about volcanoes, visit this page
December 11, 2006Alicia (Canada)How are volcanos on earth formed?Volcanoes form when hot material from below, called magma and gathered in a magma chamber, rises and leaks into the crust. For more interesting information about volcanoes, visit this page
December 11, 2006 what is the distance from earth to the sunThe Minimum Distance of our planet from the Sun is 146 million km (91 million miles) and the Maximum Distance is 152 million km (94.5 million miles).
December 11, 2006sheila (philippines)what is faultingFaulting is part of the process which causes volcanism and continental drift. As the Earth's crust is stretched or shoved during the seafloor spreading process, the rocky material of which it is made will fracture. These fractures are called "faults". More information on this topic can be found at our web page Faulting
December 9, 2006Jesette (fl)How does igneous rock form?Igneous rocks are formed underground or above ground. Underground, they are formed when the magma, deep within the earth, becomes trapped in small pockets. As these pockets of magma cool slowly underground, the magma becomes igneous rocks. They are also formed when volcanoes erupt, causing the magma to rise above the earth's surface. Igneous rocks are formed as the lava cools above grou
December 9, 2006Michelle (California)how did earth get its' moon?There are three theories about how the moon came to be in place: - that the moon came out of the crust of the Earth - that the moon was captured by the Earth - that the Earth and moon formed together out of the primordial nebula More information can be found at our web page The Formation of the Moon
December 9, 2006Dagmawit (Canada)Why are there four seasonsThe seasons are caused as the Earth, tilted on its axis, travels in a loop around the Sun each year. Summer happens in the hemisphere tilted towards the Sun, and winter happens in the hemisphere tilted away from the Sun. As the Earth travels around the Sun, the hemisphere that is tilted towards or away from the Sun changes. For a more detailed explanation, please visit our web page Earth's Tilt Is the Reason for the Seasons!
December 9, 2006julia (oklahoma)how do we get a year.A year is defined as the time required for a full revolution of the planet around the Sun. For our planet it is 365 days 5 hrs.
December 9, 2006JoAnn (Fargo, ND)Why do diagrams of the earth orbiting the sun always appear as more of an oval than the circle that you say it is? This is very confusing to students, and I think helps perpetuate the myth that the seasons are caused because of the earth being further from the sun at certain times of the year.Actually, the orbit of the Earth is not a circle, but is very close! In mathematics, eccentricity is a parameter associated with every conic section. It can be seen as a measure of how much the section deviates from being circular. In particular, the eccentricity of a circle is zero, and the eccentricity of a (non-circle) ellipse is between 0 and 1. For our planet this parameter is 0.017, meaning an orbit very close to a circular shape.
December 9, 2006Shawn(FL./USA)If the earth and the moon were formed at about the same time, why are the mountains on the moon so smooth compared to the mountain peaks of earth?There are two main factors that differentiate the mountains on the Moon and on Earth. The Earth is tectonically active and the Moon is not. The plate tectonics are constantly building new mountains on our planet, while the mountains on the Moon are very old. The second factor is the existence of an atmosphere on Earth, and not on the Moon. Due to these factors, the Moon is shaped by asteroid or comet impacts (on Earth, most asteroids vaporize before they can reach the surface.)
December 9, 2006Jasmine (Ohio/Unitedstates)What determines the speed of seismic wavesThe mechanical properties of the rocks that seismic waves travel through determine the type (and velocity) of the waves. Compressional or primary waves, travel at speeds between 1.5 and 8 kilometers per second in the Earth's crust. Shear or secondary waves travel at 60% to 70% of the speed of primary waves.
December 6, 2006Lorannia (Texas)How long does it take the moon to orbit?It takes the Moon 27.322 days to go around the Earth once.
December 6, 2006Ariel (Massuchusetts)What is the Moon's atmosphere?The Earth's Moon does not have any atmosphere
December 6, 2006daniela (philippines)why a volcano is formMagma, rising from lower reaches, gathers in a reservoir, in a weak portion of the overlying rock called the magma chamber. Eventually, but not always, the magma erupts onto the surface. The accumulation of solidified lava from different eruptions forms the volcano. More information can be found at our page Volcano Formation
November 30, 2006Celina (Philippines)When lava cools, does it become part of the land?The rocks are classified in three groups: Igneous rocks: formed from the cooling and solidification of magma (lava). Sedimentary rocks: formed at the surface of the Earth from the accumulation of sediments. Metamorphic rocks: formed within the Earth's crust when other rocks are subjected to pressures or heat so intense that they are completely changed.
November 30, 2006sweet (philippines)what are the characteristics of metamorphicMetamorphic rocks are formed within the Earth's crust when other rocks are subjected to pressures or heat so intense that they are completely changed.
November 30, 2006antone(philippines)how does lightning form?In a calm sky, the positive (+) and negative (-) charges are evenly distributed and so the calm sky has a neutral charge. Inside a thunderstorm, electric charge is divided, with + charge at the top and - charge at the bottom. Under these conditions, the ground has + charge, and because opposite charges are attracted, .the - charge at the bottom of the thunderstorm cloud wants to meet the + charge of the ground. The jump of the charges happens so fast that all we can see is a line of light. This is called lightning. More information on this topic can be found in our page Lightning Formation
November 30, 2006bin (new york)what was the span of the period paleozoicThe Paleozoic Era, between 286 Millions and 570 millions of years ago, is divided in to the Permian, Carboniferous, Devonian, Silurian, Ordovician and Cambrian periods. For detailed information visit our page An overview of Geologic Time
November 30, 2006Jhalak (Alberta)how many ice ages were there and where and how did it happen?The main glaciations are concentrated into four time intervals. Important glaciations occurred during the late Proterozoic (between about800 and 600 million years ago), during the Pennsylvanian and Permian (between about 350 and 250 million years ago), and the late Neogene to Quaternary (the last 4 million years). For more detailed information visit our page An overview of Geologic Time
November 22, 2006Katie (Me, USA)What is the second brightest object in Earth's sky?The Sun is, by far, the brightest object in Earth's sky, and is followed by our Moon.
November 20, 2006Brianna (North Carolina)How long does it take the moon to rotate on its axis?The Moon rotates over its axis vey slowly. It takes 655.728 hours to complete one full rotation. The Earth rotates over 27 times in the same period!
November 12, 2006veronica (Colorado/United States)What is the process that produces an igneous rock, a sedimentary rock, and a metamorphic rock?The rocks are classified in three groups: Igneous rocks: formed from the cooling and solidification of magma. Sedimentary rocks: formed at the surface of the Earth from the accumulation of sediments (fragments of rocks, minerals, or animal or plant material) Metamorphic rocks: formed within the Earth's crust when other rocks are subjected to pressures or heat so intense that they are completely changed. For more information about Rock and the Rock Cycle visit this page
November 19, 2002Erika (Texas, USA)What divides the west and east hemsiphere?The prime meridian is the line of longitude that divides the Western and Eastern hemispheres.

August 31, 2002Richard (Florida, USA)How old is the Earth?The Earth was formed when the Solar System formed, 4.6 Billion years ago. When Earth was young, it was a very different place than it is today!

April 6, 2000Paul (Rhode Island, USA)Is there a website that has a live image of earth from a satellite?Sure! Two you might try are Earth View and Planet Cam.
April 6, 2000Itocan (Japan)Leap year : Why is extra day added every four years?A year is a leap year (and so contains a February 29) if it is divisible by 4. But if the year is also divisible by 100 then it is not a leap year, unless it is divisible by 400. This means that years such as 1992, 1996 are leap years because they are divisible by 4 and are not affected by the rest of the rule which applies to century. Century years are not leap years except where they are a multiple of 400. Hence, the years 1700, 1800 and 1900 were not leap years and did not contain a February 29. But the year 2000 is a leap year, the first such century leap year since 1600. The reason this rule exists is because the actual time it takes the Earth to revolve around the Sun is 365.2422 days, making leap years necessary if we are to maintain the seasons at the proper times.
November 29, 1999Kirsteen (Scotland)What is the volume of the moon compared to the volume of the earth?The volume of the Moon is 2.1968x10^10 km^3, and that if the Earth 108.321x10^10 km^3. The ratio of the Earth's volume to the Moon's is 49.31.
November 29, 1999Marilyn (Alabama, USA)What is the 'ring of fire'?The Ring of Fire is an area where there are a large number of volcanic eruptions and earthquakes. The zone forms an area surrounding the Pacific Basin, hence the 'Ring' of Fire.
November 25, 1999Dolores (Missouri, USA)What is Indian summer and blackberry winter? Thank you for your answer. I found my answer to harvest moon on this site.Indian summer is the first warm period after the first frost of the fall/winter season. Blackberry winter is the last cold spell before warm spring/summer weather is here to stay. This supposedly occurs when the wild blackberries are blooming.
October 23, 1999Drew (Virginia, USA)my geography teacher says the earth is flat but I think it is a sphere, can you prove who is right?Today, we can easily show the Earth is round by looking at pictures taken from space. One way of showing the Earth is round is by looking at ships sailing over the horizon. They disappear from the bottom up, until only the top of the mast can be see n, and then that disappears as well. If the Earth were flat, we would see the ship just get smaller and smaller until it was almost a dot, and then disappear. Many years ago, the astronomer Eratosthene s showed that the Earth is round. He also calculated the size of the Earth, very nearly correctly!
August 25, 1999Jessica (Georgia)How many pennies would it take to go around the Earth?The answer can be found by using a little math. The diameter of the Earth is about 12,723,000 meters. The diameter is the length from one side of the circle to the other.

To find the length around the Earth, you must multiply the diameter by pi, which is about 3.14. Now, find the diameter of one penny. It is about 2 centimeters, but you can measure one yourself!

If you divide the circumference of the Earth by the diameter of a penny, you will find that almost 2 billion pennies are needed to make a line around the Earth!

July 8, 1999Ashley (Canada)How many Earths could fit in the Sun?Over 1.3 million Earths could fit inside of the Sun. The Sun actually contains about 99% of the mass in the solar system, so it makes sense. It still blows me away every time I think about it though.
June 2, 1999Gary (California, USA)Do glaciers demonstrate similar fluid dynamics to rivers.To a degree glaciers demonstrate some variances in flow. For instance, glaciers flow faster on top and in the center than at the bottom and sides. They also flow faster after winters with heavy snow falls. However, glaciers only flow in one direction, downhill with gravity or outward from its source if on a flat plain. So, glaciers do not demonstrate eddies or back flows. In fact, even when a glacier is receding it is moving forward. The shrinking happens because it is melting faster than it moves forward.
May 24, 1999Tim (Michigan, USA)What is the sea level of Detroit, MI?Detroit's altitude is 177 meters (581 feet) above sea level, measured at the Detroit River.
March 11, 1999Brian (Colorado, USA)Which is hotter: lightning or volcano lava?Lightning has lava beat hands down. Even though it occupies a much smaller area (the plasma channel is only centimeters across), lightning has a temperature of around 7,000°C while lava has a temperature of around 1,000°C.
August 11, 1998John (Ohio, USA)Is there a Globe that just shows the earth? By that I mean a regular globe that shows 'no water', where you can see just the earth as it is with no water, you know the contour of all the lands which somehow meet below the oceans and lakes? I've had this idea for a few years but don't know if its possible to build a globe like the one I'm thinking of, and or who to ask about it? I figured I might as well ask you guys, if you can help me on this search for a globe with no waters, just earth?I've never seen a globe that didn't include water, but I wouldn't be surprised if they existed! One thing I have seen are maps of ocean topography that don't include the water of the Earth, so that you can see what the ocean bottom looks like. These are found in most general Earth science books (especially text books) as well as on some web sites.
May 27, 1998David (Florida, USA) I am told that draining water turns in opposite directions on opposite sides of the equator. If this is true, what is the cause? Do cyclonic storms turn in different directions in different parts of the earth?Yes, this is true. In the Northern Hemisphere, water would swirl counterclockwise; in the Southern Hemisphere, the water would run out clockwise. This is due to the coriolis effect. The coriolis effect is when the Earth's rotation has effect on any moving body of air or water. BUT! For this experiment to work, some extreme measures must be taken. The sink used (or bathtub, etc.) must be symmetrical and of smooth surface. The water must also be left to drain for almost three hours for the Coriolis effect to be seen. You see, forces issued on the water such as those during washing are much stronger than the Coriolis force itself.

Since the coriolis effect affects winds too, cyc lonic storms do turn different directions in the different hemispheres.

April 17, 1998DeSharla (Tennessee, U.S.A.) How can Scientist tell the Age of the earth using the layers?Scientists cannot actually tell the age of the Earth just by looking at different layers. Through looking at layers, they can see that the deeper layers must be older, and the layers on top must be the newest. To tell how old the Earth is, scientist s use a scientific method called radio carbon dating. This gives them the actual approximate age of the Earth, which is about 4.6 billion years.
April 7, 1998Ahmet (Ankara, Turkey) I want to observe the sattelites of earth, how can I find them on the sky?Sattelites can be seen at night every few minutes. Many move west to east, and some (military) move north/south or south/north. Sattelites look like steadily moving stars, bright or faint. They may blink somewhat, but it will be erratic. If there is a steady, regular blink, or if it makes noise, it is an airplane!
February 19, 1998Andrew (Louisiana, USA) How much does the Earth weigh?The mass of the Earth is 5.98 x 10^24 kg. That's 598 trillion trillion kilograms!
December 31, 1997Brett (New Jersey, USA)How did the Earth get its name?The English name for the earth is from the Old English and Germanic languages. Earth is the only planet whose English name does not come from the Greek and Roman Mythology. There are, of course, many other names for the Earth in other languages.
December 31, 1997Justin (Florida, USA)Is the Earth taller or wider?The Earth is slightly wider around the equator than it is tall. The diameter at the equator is 7,925.77 miles, while the pole-to-pole diameter is 7,899.09. This difference is caused by the spinning motion of the earth.
December 30, 1997---I really need to know about this, is there an edge to the earth? It is for a science project.That depends on what you mean by an 'edge'. Unlike Jupiter and Saturn, which are composed almost entirely of gas, the Earth has a solid surface, which could count as an edge. But the Earth also has a gaseous atmosphere above its surface. The atmosphere doesn't end abruptly, but gradually fades away into space.
December 8, 1997Marie (Wisconsin, USA)What is the coldest temperature ever recorded on Earth and the location of this recording?The coldest air temperatures on Earth have been found near the South Pole in the -130o F range. The coldest temperature that can be achieved anywhere is called "absolute zero" and is -460o F, or -273.16o C. On Earth, the closest you're ever likely to get to absolute zero would be liquid helium, with a temperature of -452o F!
December 2, 1997Hilary (Florida, USA)How many miles is it around the Earth?The distance around the Earth, also known as its "circumference", is 24,906 miles. This means if you were driving non-stop at the speed limit of 65 miles per hour, it would take you 383.2 hours, or nearly 16 days to make the trip! If you're driving, get a good set of water wings for your car--most of your trip will be across oceans!

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