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.

As permafrost thaws, the land, atmosphere, water resources, ecosystems, and human communities are affected. Coastal areas and hillsides are vulnerable to erosion by thawing of permafrost. Thawing permafrost also causes a positive feedback to global warming, as carbon trapped within the once-frozen soils is released as <a href="/physical_science/chemistry/methane.html">methane</a>, a powerful <a href="/earth/climate/cli_greengas.html">greenhouse gas</a>. Watch the NBC Learn video - <a href="/earth/changing_planet/permafrost_methane_intro.html">Thawing Permafrost and Methane</a> to find out more.<p><small><em>Image courtesy of the USGS</em></small></p>As temperatures rise and soil moisture decreases, plants are stressed, which can lead to <a href="/earth/climate/crops_withering.html">crop withering</a>. <a href="/teacher_resources/online_courses/health/events_health.html">Droughts</a> accompanied by increased temperatures can lead to famine, social and political disruptions. Scientists are helping with early identification of drought that might trigger food shortages. Watch the NBC Learn video - <a href="/earth/changing_planet/withering_crops_intro.html">Changing Planet: Withering Crops</a> to find out more.<p><small><em>Image taken by Tomas Castelazo, Creative Commons <a href=&quot;http://creativecommons.org/licenses/by/3.0/deed.en&quot;>Attribution 3.0 Unported</a> license.</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">full phase</a>. Secondly, the <a href="/sun/sun.html">Sun</a>, <a href="/earth/earth.html">Earth</a> and <a href="/earth/moons_and_rings.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>This iconic image of Earth rising above the surface of the <a href="/earth/moons_and_rings.html">Moon</a>, was taken on December 24, 1968 by astronauts on the <a href="/space_missions/apollo8.html">Apollo 8 mission</a>.  Apollo 8 was the first <a href="/space_missions/manned.html">manned mission</a> to the Moon, and entered into lunar orbit on Christmas Eve.  That evening, the astronauts held a live broadcast from lunar orbit, in which they showed pictures of the Earth and moon as seen from their spacecraft.<p><small><em> Image courtesy of NASA</em></small></p>An artist's rendering of the moment of impact of a massive <a href="/our_solar_system/meteors/meteors.html">meteorite</a> at the end of the Cretaceous (at the end of the <a href="/earth/geology/hist_mesozoic.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">mass extinction of dinosaurs</a> and many other life forms.  Recent research suggests that perhaps <a href="/headline_universe/olpa/chicxulub.html">massive volcanic eruptions</a> may be been responsible for the extinction.<p><small><em>Courtesy of Don Davis, NASA</em></small></p>A sinuous glowing band of <a href="/earth/Magnetosphere/aurora.html">aurora</a> (the Aurora Australis or Southern Lights) loops around the <a href="/earth/polar/polar_south.html">southern polar</a> region in the distance as viewed by astronauts onboard the space shuttle on <a href="http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/archives/sts-39.html">STS-039</a>.     <a href="/earth/Magnetosphere/aurora/aurora_colors.html">Aurora are produced</a> when <a href="/physical_science/physics/atom_particle/particle_radiation.html">energetic particles</a> entering the Earth's atmosphere from space interact with <a href="/physical_science/physics/atom_particle/atom.html">atoms</a> and <a href="/earth/geology/molecule.html">molecules</a> in the atmosphere and release energy, emitted as light. <p><small><em>Courtesy of NASA, Astronaut Overmeyer and Dr. Hallinan</em></small></p>

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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

Myth and Culture

In cultures around the world, humans have developed stories to help them understand how the ...Read more

Research Expeditions

When scientists go out to explore the Earth they often wind up in pretty interesting places ...Read more

More about Earth

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Earth and Space Science Concept of the Day

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Rayleigh wave
xRayleigh wave : A Rayleigh wave is a seismic surface wave causing the ground to shake in an elliptical motion, with no transverse, or perpendicular, motion.

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Research Highlights

New Computer Model Advances Climate Change Research

Scientists can now study climate change in far more detail with powerful new computer software released by the National Center for Atmospheric Research (NCAR) in Boulder, Colo. The Community Earth System...Read more

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