| Date Answered | Questioner (age, location) | Question | Answer |
| Mar 27, 2000 | Darla (age 11, shelby co. mo) | where can I find good space info? |
Try this site here... |
| Jan 31, 2000 | Rachel (age 14, Idaho) | Where can I go to colage if I want to be an astronomer? How much does it cost to become one? |
The American Astronomical Society has a good page on Careers in Astronomy which should help you out. |
| Jan 25, 2000 | Christine (New Jersey) | My question is....What exactly is planet "X"? is it an accual planet?.. or just a "something" thats out there and hasn't been discovered yet? |
Planet X used to be the name for a proposed 10th planet. The "X" stands for the "unknown quantity." Now you may ask, what makes scientists think that there is a 10th planet? The reason is that there is are laws of nature (Kepler and Newton) which balance the motion of the planets with how much mass is in the solar system. So far, even with the discovery of Pluto, these laws suggest that there may be another planet still to be discovered. (By the way, it was by using this law that the planets Neptune and Pluto were discovered in the first place - that is, scientists knew that they should look for more planets because the law could not be balanced).
The Voyagers' results have now yielded more accurate measurements of the masses of the planets. It now looks like that 10th planet can be satisfied by the material which is in the Kuiper Belt, an astroid belt outside of Neptune and Pluto. So there probably is no planet X. |
| Jan 13, 2000 | Johnny (age 9, ) | Why is the ocean blue? |
When sunlight hits the ocean it is scattered by the water molecules that make up the ocean. Sunlight is made up of all of the colors of the rainbow (red through violet). Water molecules scatter blue light the most. This makes the ocean look blue. Sometimes the ocean doesn't appear blue! Many parts of the ocean look green. This is because the blue we would normally see is mixed with the yellow coloring of floating plants...blue and yellow make green! |
| Oct 29, 1999 | Glenn (age 38, ca, usa) | what is the largest star we have found so far? |
Mu Cephi, known as the Garnet star, is the largest star known. Its radius is 2536 times the solar radius. |
| Oct 29, 1999 | Marie (age 13, Canada) | I read that Proxima Centauri is the closest star to the Sun since it is 4.2 light years away, so why do many people think that Alpha Centauri,4.35 light years away, is the closest star to the Sun? |
There are several reasons behind people thinking this. First of all, Alpha Centauri was discovered much earlier that Proxima Centauri. This caused it to become recognized and known as the closest star before P. Centauri had even been discovered. Another important reason is that Alpha Centauri is the dominant star in the three star system of which it and Proxima Centauri system. In other words, it is correct to say that the Alpha Centauri system is the closest star system to our Sun. |
| Oct 29, 1999 | Jessica (age 13, MA) | Why is it that as you move closer to the event horizon of a black hole you appear to be moving in slow motion, and when youreach the event horizon, you appear to freeze? |
This is only how things appear to distant observers. The object being captured by the black hole would not experience a freeze. This occurs because as the object is accelerated toward the event horizon the light reflected or emitted from it becomes redshifted. The last photon of light emitted would be infinitely redshifted, and the object will appear to be frozen just above the event horizon. |
| Oct 8, 1999 | ait obraim (age 40, tangier/morrocco) | Are current space missions bringing any answer to the possibility of life on other planets. |
Recent space missions have not confirmed the existence of life on other planets, and whether or not there is life off of planet Earth is still highly debated. However much of the information collected by space missions has helped us to detirmine where life is possible. For instance, the Cassini mission to Saturn will do an indepth study of Titan, one of the likeliest locations in the Solar System to shelter life, to determining if life exists, or at least is possible there. |
| Oct 6, 1999 | Carlos (age 54, Puerto rico) | In the solar view of SOHO EIT the Sun appears to be rotating and all flares to emanate from near the center & not from the poles. Why is this so? |
The reason there is rotation is because SOHO is taking several pictures from over many days and putting them together in a movie. There is a pattern of sunspots and flares known as the butterfly pattern where in over the Sun's eleven year cycle sunspots start at higher latitudes and are prgressively confined to more equatorial bands. The mechanism behind this is unknown. |
| Oct 6, 1999 | Craig (age 32, NJ, USA) | In movies like Star Wars, etc., things like the asteroid belt are always shown as these violent places full of constant collisions, etc. What's the real asteroid belt like? If you lived on an asteroid, would you even be able to see the asteroids around you, let alone be in imminent danger of a collision? | The asteroid belt between Mars and Jupiter has some 100,000 asteroids in it. This may sound like alot, but they are spread out in a huge volume of space, between 130 million miles and 480 million miles. If you lived on an asteroid it would be very unlikely that you could see more than a couple others, and constant collisions with other asteroids would not be a very big danger. |
| Oct 6, 1999 | Christine (age 12, Virginia) | During a lunar eclipse, what are the two shadows that form called? Also, is it true that only five planets are known to have moons? |
The shadows are called the Umbra and Penumbra. You can find more out about eclipses and see a diagram from a solar eclipse (which is the same basic concept) here. Of the nine planets, seven are known to have at least a moon, with Mercury and Venus being the only two not have one. Since the Earth and Pluto only have a single moon, I guess its true to say that only five planets are known to have moons. |
| Oct 6, 1999 | Steve (age +40, Germany) | Is it correct that the planets are presently all in line and if so would this be a possible answer as to why we have recently experienced such terrible earthquakes? |
The planets are not presently in a line. You can find the position of all the planets now, or on any other date, here. Even if all the planets are near to a line (they can never be exactly in a line because they are in slightly different plains) they have no measurable effect on Earth. The other planets are simply too far away to have anything over the minutest physical effect on Earth. |
| Sep 29, 1999 | Mick (age 14, united kingdom) | Are there more stars in the universe than grains of sand? | It depends, if you don't qualify that statement and leave it open ended, the answer is no. Even if only one out of every million stars has a planet with similar amounts of sand on it as the Earth has than there is much more sand than stars. However, if you change the statement to say "are there more stars then grains of sand on the Earth" the answer is a resounding yes. In the visible universe alone there are 100 billion galaxies, each with a few billion stars, which gives you about 10^20 stars. The mass of sand needed to equal this number of stars is much more than its estimated amount on Earth. Furthermore, the Universe is bigger than just what we can see. |
| Sep 27, 1999 | Richard (age 66, Missouri) | Has anyone ever studied how the magnetic poles have their effect on the weather? | Scientists have definately studied what effect the Earth's magnetic field has on weather. Without the magnetic field the Earth would be exposed to high amounts of radiation and charged particles from the solar wind, so the magnetic field acts like a buffer and shield to Earth's atmosphere and surface. From what I know, no one has discovered a signinficant correlation between the behavior of the magnetosphere or magnetic poles and weather. |
| Sep 27, 1999 | Reid (age 25+, Florida) | Where does space end, and nothing begin? Where is the end of the universe, as we know it? |
This is a pretty tricky concept. One answer is that nothing does not ever begin. Our Universe is expanding, but it is not expanding into anything. Space does not have any reality outside of the Universe. It is not only a void outside our Universe, but a non entity, nothing exists outside the Universe that has any reality for us. The visible Universe has a radius of about 15 billion light years, but we really don't know exactly how big the Universe is. Because space time is curved it might be helpful to think of us existing on the inner surface of a giant sphere. If we travel in any direction we could continue forever, never coming to the edge. In other words, it is possible to have a physical size, but no edge. |
| Sep 24, 1999 | Federico (age 20, Argentina) | What are quasars? What is the relationship between Quasars and black holes? |
The relationship between Quasars and black holes, as well as the nature of Quasars, can be found here. |
| Sep 24, 1999 | Cristina (age 23, Austin, Texas) | Is it possible for a planet rotating on its axis to simply cease its rotation, and if so, what type of cosmological event could possibly cause this to occur? |
The answer is yes, although the process is by no means a simple one. It is a law of physics that an object in motion will tend to stay in motion unless acted upon by an outside force. Since something like a planet is so massive it takes a large force indeed to make any significant change in its rotation. However, it is possible for planetary rotations to change. Venus has a very slow retrograde rotation. It is believed that this could be the possible result of an ancient collision of enough strength to reverse Venus' rotation. The Moon has one side which always points towards the Earth, and the Earth's rotation is slowing down so that someday (a long time from now) Earth will have one face which always points towards the Moon (find an explantion for this phenomenon here). |
| Sep 24, 1999 | Jason (age 20, Ontario, Canada) | What is the reaction of time on objects traveling near to light speed? |
Your question has been addressed on our main Windows to the Universe site before here. |
| Sep 24, 1999 | Fred (age 57, Florida, USA) | If a space traveler traveling at the speed of light took a flashlight and turned it on, holding the light perpendicular to the line of travel what would the beam of light do? | First of all, your question needs to be rephrased slightly. Only light or something else without mass can travel at the speed of light. Nothing with mass can travel at the speed of light, but we can say that a space traveler traveling near the speed of light turns on a flashlight pointing perpendicular to the line of travel. If we arbitrarily say that space traveler is heading north, then the beam would travel east. The beam would leave the flashlight at the speed of light and travel due east without any northward component of velocity (otherwise the beam would be traveling faster than the speed of light, an impossibility). To a stationary observer this beam would appear as a momentary flash. The only way to see a continuous beam would be if another space traveler was traveling at the same speed parallel and slightly behind the first traveler. |
| Sep 20, 1999 | Darren (age 34, Illinois, USA) | Logically speaking, how can you get something from nothing? Basic physics states that matter cannot be created or destroyed, so where did the matter for the Big Bang come fro originally? Has anyone theorized that maybe "our" universe was created as a result of some type of reaction that occurred in an already existing universe? | Interesting question, and the answer is yes. One such current theory involves such concepts as bubble universes and false vacuums (treated in some detail here). Basically stated, some physicists theorize that super high densities of matter can turn gravity on its head, causing it to become a repulsive instead of attractive force. This state, known as a "false vacuum", creates another universe, or "bubble universe", by breaking off from the parent. Some believe that there might be an infinite number of bubble universes, with more constantly being created. Of course, even if the matter in our universe originated in another, the question of where the matter from the original universe came from is still begged, and no one seems to have a very good answer for that. |
| Sep 20, 1999 | Bruce (age 39, New Jersey/New York USA) | What is the formula that breaks down the possibility of life on other planets? | The formula, known as the Drake equation or the Sagan equation was first developed by Frank Drake in 1961. The equation is as follows: gs*fs*ne*fl*fi*fx*L=N where gs is the rate of star formation in the galaxy, fs is the fraction of stars which can support planets, ne is the fraction of planets that are habitable (earth-like), fl is the fraction of planets where life originates, fi is the fraction of those on which a lifeform has developed intelligence, fc is the fraction of those which have the technology and will to communicate, L is the mean lifetime of a communicative civilization, and N is the number of communicative civilizations. This formula is the basis for such programs as SETI (the search for extraterrestrial intelligence) of which Frank Drake is the current head. |
| Sep 17, 1999 | Miguel (age 27, Lisbon, Portugal) | Is it possible to produce ozone artificially ? |
Yes, it is possible to artificially produce ozone. It is produced as a byproduct of industry, and can also be produced directly. However, ozone produced in this way usually remains close to the Earth's surface, and is the "bad" ozone you might have heard of. It is actually a particularly nasty form of pollution and is very toxic to living things. Even if ozone is moved to (or produced in) the upper atmosphere where it is beneficial it does little good. The reasoning behind this is slightly complicated. The amount of ozone in the atmosphere has a natural equilibrium level. This means that if ozone levels are above this equilibrium point more ozone is destroyed than produced, and the level returns to the equilibrium point. The opposite happens when ozone levels are low. The problem is that chemicals people release, such as CFC's, destroy ozone and lower this natural equilibrium point. So, if we try to add ozone to the atmosphere to raise levels to the old and safe concentrations, the ozone will be destroyed and return to the new and lower equilibrium point. In fact, the only way for the ozone layer to recover is if we stop releasing chemicals like CFC's into the atmosphere. Once these chemicals are out of circulation ozone levels will rise. |
| Sep 17, 1999 | Matt Astill (age 15, Australia) | How many kilometers is 4.2 light years away from earth? |
4.2 light years would be 3.97x10^13 km away! |
| Sep 17, 1999 | Luis Mario Loor (age 32, Quito, Ecuador) | Why is the year 2,000 a Leap Year? |
When the Gregorian calendar was being created, the length of the year had to be adjusted a bit. This is because one year is not exactly 365 days long, but a bit more. So, they added a leap day every once in a while. The rule for leap years is this: Every fourth year is a leap year, except for century years that are not divisible by 400. So, since 2,000 IS divisible by 400, it is a leap year. |
| Sep 17, 1999 | Ben Williams (age 12, North Carolina) | Did Thomas Edison invent a light bulb that is still working and has been since he made it? |
No. The first light bulb which worked glowed for 13 hours before the filament broke. Once Edison had a working model of a light bulb, he began working on a method to supply power to future bulbs. |
| Sep 10, 1999 | Orlando (age 20, TN/Nashville) | What is the distance between the Earth and outer space? How long does it take a space shuttle to travel the distance between Earth and space with no gravity. |
There is not an exact starting place for where the Earth's atmosphere ends and space begins. The Earth's atmosphere just gets thinner and thinner as you travel higher and higher. Most scientists (if hard-pressed) would say that the atmosphere ends around 100 kilometers above the Earth, but even at that height, part of the Earth's atmosphere is there (mostly hydrogen). The force of gravity exists everywhere, It simply ceases to be as noticeable the farther one is from Earth (or any other massive body). However, the space shuttle takes around eight or nine minutes to establish orbit (at which point astronauts experience microgravity conditions). |
| Sep 7, 1999 | Tokee (age 16, Jakarta, Indonesia) | If the universe started with a big bang, it should look similar to when a skyrocket explodes: everything expands outwards and there is a big hole in the middle. Are scientists looking for a big hole? Shouldn't a big hole be necessary for the big bang theory? |
Actually, a hole is not a component of the big bang theory, so scientists are not looking for one. After the big bang everything started to expand in all directions at many speeds. In other words, instead of everything expanding in a single shell, some things may have exploded in the same direction but different speeds. So, even if some things are traveling in the same direction they might be getting farther apart. It helps me to think of the Universe expanding with more and more space between objects, but not one specific hole where the big bang occurred. |
| Sep 7, 1999 | Adelynne (age 15, Kuala Lumpur, Malaysia) | Why doesn't Mercury and Venus have their own moons? Pluto is the smallest planet in the universe and yet it has Charon as its moon. Thank you. |
Actually, Pluto is just the smallest known planet. Scientists are not able detect planets much smaller than the size of Jupiter, so it is very likely that there are many planets Pluto's size and smaller out there in the Universe. Size plays a role in how many moons a planet has (the gas giants have many more moons than the terrestrial planets do for example). However, size is not the only determining factor. There are many possible reasons why Mercury and Venus do not have moons. It is possible that there were simply no asteroids near enough to the planets to have been captured as moons. |
| August 6, 1999 | Jeanna Goodrich (age 13, Texas) | Are people able to live on Jupiter's moon Europa, considering the elements that are located on that moon? |
Europa is an icy moon, and having a supply of water available is one of the most important aspects of any human colony in space, so that makes it a good candidate. However, Europa would present some unique challenges. Building structures on ice is tricky business, any heat released by the building is liable to melt its foundations and destabilize it. Because Europa has no atmosphere any settlements would have to be self contained. |
| July 27, 1999 | Chelsi (age 14, California) | What is the difference between a solar eclipse, and a lunar eclipse? | A solar eclipse occurs when the Moon comes between the Earth and the Sun, so the light from the Sun is blocked. A lunar eclipse happens when the Earth comes between the Moon and the Sun, so that when we look at the Moon we see the shadow of the Earth on the Moon. |
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| July 18, 1999 | Kiefer (age 10, Kansas) | Are there tornados in space? | Last year, there were tornadoes found on the sun. Also, Jupiter's Great Red Spot is thought to be a hurricane type system. |
| July 1, 1999 | Kyle (age 15, Pennsylvania) | Has Pluto lost its planet status because it is just gas? | Actually Pluto is rocky, with little if any atmosphere at all. We have a page on our site addressing the Pluto planet debate, you can find it here. |
| June 27, 1999 | Ben (age 11, England) | Where did the Sun come from? Will the Sun ever cool down? Why does the sun remain static? | The Sun formed from a collapsed interstellar dust cloud. The Sun is actually very active, you can see how right here at SPARC. The Sun should stick around for at least another five billion years. |
| June 15, 1999 | Conner (age 47, Mississippi) | The real name of the Earth is Terra, the real name of the Moon is Luna; what is the real name of the star we call the Sun? | Although Terra is a name for the Earth, and Luna is a name for the Moon, they are no more real than the names Earth and Moon. Just because a name is in common usage does not mean it is not 'real' or 'scientific'. The names for the planets and the Sun are not like binomial nomenclature for naming species where there is a scientific name and a common name. On the other hand the Sun is sometimes called by different names. One of the most common is Sol. To see more you could check out our page on Sun mythology here. |
| June 11, 1999 | Mark (age 43, California) | Is our ionosphere in trouble? | I've been studying the ionosphere for a few
years now...and I'm not sure why it would be in
any trouble!? The column height (the thickness)
certainly changes every day and night and when
the Sun is particularly active, but that is its
normal state. We bounce our radio waves off of the ionosphere...and that seems to be working fine too. |
| June 1, 1999 | KC (age 12, Minnesota) | Where does a black hole lead to? | Good question, black holes are one of the hardest things to understand in astronomy. The current understanding is that they don't lead anywhere but themselves. They are so massive that nothing can escape them and the way that they warp space time. For a bit more on what might happen inside black holes go here. |
| May 29, 1999 | Joanne (age 17, England) | What current predictions are there for the end of the Universe | Check out the Windows to the Universe page about the future universe for the answer. |
| May 27, 1999 | Chris (age 32, New York, USA) | How strong is moonlight compared to sunlight? | The Moon has an albedo of 7. This means that it reflects 7% of the Sun's light. Since the Moon's light is only a reflection of the Sun's, its maximum brightness is 7% that of the Sun's. |
| May 26, 1999 | Ricardo (age 37, Massachusetts , USA) | How will the solar flares of the next 10 to 18 months affect life on earth? Will there be black-outs? Will it affect the melting of the polar ice caps? | We are entering a time of increasing solar activity. The solar maximum is predicted to occur somewhere during 2000-2001 (although we won't know until after it occurs). The solar max is likely to cause increased problems with things like cell phones and satellite communications. Its affect on the weather is another story. Some scientists think that increased solar activity will cause a warmer climate. This has not been proven, and everyone agrees that whatever the effect, it is minimal, and not enough to cause a significant change in the polar icecaps. |
| May 23, 1999 | Paranoid (age 22, Kenya) | What is a black hole and what are its properties? | To find out about black holes, you might try looking at this page at Windows to the Universe about black holes. |
| May 18, 1999 | Maz (age 33, California, USA) | What is the radius of the sphere which houses the current universe? | Interesting question, defining the 'current' Universe is quite tricky. What we can observe is not truly current. Even the light we see from the sun left it eight minutes ago. Scientists most recent estimate for the age of the universe is 12 billion years (the oldest visible object is 11 billion years old). So, the farthest anything could have traveled is 12 billion light years. But, a radius is a length from a center to the edge, and the Universe does not technically have a center, or more correctly, since the Universe is expanding, every point could be considered the center (don't let your ego get too big) because the overwhelming majority of matter in the Universe is moving away from it. Because of this the concept of a radius losses meaning. |
| May 18, 1999 | Bill (age 42, Maryland, USA) | What research is going on regarding another undiscovered planet orbiting our sun (planet X)? | Many exhaustive searches for a hypothetical planet X have been pursed by astronomers for over a century. This search was spurred on in large part because of discrepancies between the expected and observed orbits of Neptune and Uranus. These discrepancies disappeared when revised masses for the planets were given by the Voyager probes. The search for planet X but reputable astronomers has since ceased, despite some who insist that the planet exists. |