Earth

Earth, our home planet, is a beautiful blue and white ball when seen from space. The third planet from the Sun, it is the largest of the inner planets. Earth is the only planet known to support life and to have liquid water at the surface. Earth has a substantial atmosphere and magnetic field, both of which are critical for sustaining life on Earth. Earth is the innermost planet in the solar system with a natural satellite – our Moon. Explore our beautiful home planet – unique in our solar system - through the links in this section.

Sinkholes are <a href="/teacher_resources/main/frameworks/esl_bi8.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">natural hazards</a> in many places around the world. They are formed when water dissolves underlying <a href="/earth/Water/carbonates.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">limestone</a>, leading to collapse of the surface. Hydrologic conditions such as a lack of rainfall, lowered water levels, or excessive rainfall can all contribute to sinkhole development. On 2/28/2013, a sinkhole suddenly developed under the house outside of Tampa, Florida, leading to the tragic death of its occupant, Jeff Bush.<p><small><em>Image courtesy of Southwest Florida Water Management District</em></small></p>Greenland's <a href="http://www.windows2universe.org/earth/polar/cryosphere_glacier1.html">ice sheet</a> saw a record <a href="http://www.windows2universe.org/headline_universe/olpa/greenland_10dec07.html">melt</a> in July 2012. Scientists studying this event have found that this melting event was triggered by an influx of unusually warm air and amplified by the presence of a blanket of thin low-level <a href="http://www.windows2universe.org/earth/Atmosphere/cloud.html">clouds</a> which pushed temperatures up above freezing. For more information see the <a href="http://www.news.wisc.edu/21638">press release</a> from the University of Wisconsin Madison.<p><small><em>Image courtesy of University of Wisconsin-Madison</em></small></p>How did life evolve on <a href="/earth/earth.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">Earth</a> during the <a href="/earth/past/Archean.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">Archean</a>, when the <a href="/sun/sun.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">Sun</a> was about 25% weaker than today? The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">greenhouse</a> gas concentration was the same as today. <a href="http://www.manchester.ac.uk/aboutus/news/display/?id=10798">Researchers</a> studying the <a href="/physical_science/physics/atom_particle/isotope.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</em></small></p>Scientists at the University of Michigan have found that <a href="/earth/polar/cryosphere_permafrost1.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">permafrost</a> in the <a href="/earth/polar/polar_north.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">Arctic</a> is extremely sensitive to sunlight. Exposure to sunlight releases carbon gases trapped in the permafrost, including <a href="/earth/climate/earth_greenhouse.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">climate-warming</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">carbon dioxide</a>, to the <a href="/earth/Atmosphere/overview.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">atmosphere</a> much faster than previously thought.<p><small><em>George Kling, The University of Michigan</em></small></p>An artist's rendering of the moment of impact of a massive <a href="/our_solar_system/meteors/meteors.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">meteorite</a> at the end of the Cretaceous (at the end of the <a href="/earth/geology/hist_mesozoic.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">Mesozoic Era</a>). Many scientists have concluded for decades that a meteorite four to six kilometers in diameter impacted the Earth at this time, resulting in a <a href="/earth/past/KTextinction.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">mass extinction of dinosaurs</a> and many other life forms. Recent research suggests that perhaps <a href="/headline_universe/olpa/chicxulub.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">massive volcanic eruptions</a> may be been responsible for the extinction.<p><small><em>Courtesy of Don Davis, NASA</em></small></p>Lunar eclipses are special events that only occur when certain conditions are met. First of all, the Moon must be in <a href="/the_universe/uts/moon3.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">full phase</a>. Secondly, the <a href="/sun/sun.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">Sun</a>, <a href="/earth/earth.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">Earth</a> and <a href="/earth/moons_and_rings.html&edu=elem&dev=1/earth/Atmosphere/moons/megacities.html">Moon</a> must be in a perfectly straight line. If both of these are met, then the Earth's shadow can block the Sun's light from hitting the Moon. The reddish glow of the Moon is caused by light from the Earth's limb scattering toward the Moon, which is reflected back to us from the Moon's surface.<p><small><em>Image credit - Doug Murray, Palm Beach Gardens, Florida</em></small></p>

Explore Earth

Earth's Interior and Surface

Earth, the largest and densest rocky planet, was formed about 4.5 billion years ago. The Earth's ...Read more

Atmosphere

The atmosphere is a mixture of nitrogen (78%), oxygen (21%), and other gases (1%) that surrounds ...Read more

Magnetosphere

The Earth has a magnetic field with north and south poles. The magnetic field of the Earth ...Read more

Moon

The Earth's one natural satellite, the Moon, is more than one quarter the size of Earth itself ...Read more

Earth's Polar Regions

Do you wonder what Earth's Polar Regions are like? Where do polar bears live? Where do penguins ...Read more

Climate and Global Change

Warm near the equator and cold at the poles, our planet is able to support a variety of living ...Read more

Water (The Hydrosphere)

Water is found in many places on Earth including on the surface of the planet, within rocks ...Read more

Life and Ecology (The Biosphere)

What is life? Why is there life on Earth, but not on any other planets in the solar system ...Read more

Natural Hazards

The United Nations estimated that between 1994-2015, there were 6,873 natural disasters worldwide, ...Read more

More about Earth

Historical Events

Full Earth and Space Science    History Calendar (Members only)

Teacher Opportunities

Full Teacher Events Calendar (Educator Members only)

Did you know?

Did you know that many different cultures had myths about Earth goddesses and gods?

Did you know that the ionosphere makes radio communication possible?

 

Earth and Space Science Concept of the Day

Do you know what this word or phrase means?

Sand boil
xSand boil : A sand boil is sand and water that come out onto the ground surface during an earthquake as a result of liquefaction at shallow depth.

Click on the word to find out!

Research Highlights

Deadly Tonga Earthquake Revealed as Three Big Quakes

A magnitude-8.1 earthquake and tsunami that killed 192 people last year in Samoa, American Samoa and Tonga was in fact a triple-whammy. The 8.1 "great earthquake" concealed and triggered two...Read more


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