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.

A new study has found that <a href="/earth/Atmosphere/airpollution_intro.html&edu=elem&dev=1/moons/images/rain">pollution</a> from <a href="/earth/Atmosphere/particulates.html&edu=elem&dev=1/moons/images/rain">fine particles</a> in the air - mainly the result of burning coal or <a href="/earth/interior/eruptions.html&edu=elem&dev=1/moons/images/rain">volcanic eruptions</a> - can shade <a href="/earth/Life/cnidarian.html&edu=elem&dev=1/moons/images/rain">corals</a> from sunlight and cool the surrounding water resulting in reduced growth rates.  Coral growth rates in the Caribbean were affected by volcanic aerosol emissions in the early 20th century and by aerosol emissions caused by humans in the later 20th century.  For more information, see the <a href="http://www.exeter.ac.uk/news/featurednews/title_278202_en.html">press release</a>.<p><small><em>Image courtesy of Toby Hudson (Wikimedia Commons)</em></small></p>March 2012 marks the first anniversary of the 9.0 magnitude <a href="/earth/geology/quake_1.html&edu=elem&dev=1/moons/images/rain">earthquake</a>, <a href="/earth/tsunami1.html&edu=elem&dev=1/moons/images/rain">tsunami</a>, and resulting nuclear accident in Japan on <a href="/headline_universe/march112011earthquaketsunami.html&edu=elem&dev=1/moons/images/rain">11 March 2011</a>.  The tsunami did massive damage, wiping out entire villages and killing ~16,000 people, and leading to one of the most serious nuclear accidents in history.  This image shows before and after photos of the area north of Sendai, where 10,000 people were lost.<p><small><em>Photos by <a href="http://www.nytimes.com/interactive/2011/03/13/world/asia/satellite-photos-japan-before-and-after-tsunami.html?hp">GeoEye/EyeQ</a>.</em></small></p>This is an artist's conception of the
  Earth and the inner and outer <a
  href="/glossary/radiation_belts.html&edu=elem&dev=1/moons/images/rain">radiation belts</a> that surround it. The Earth's radiation belts are just one part of
  the system called the <a
  href="/earth/Magnetosphere/overview.html&edu=elem&dev=1/moons/images/rain">magnetosphere</a>. The radiation belts of the Earth are made up of <a
  href="/physical_science/physics/atom_particle/electron.html&edu=elem&dev=1/moons/images/rain">electrons</a>,
<a
  href="/physical_science/physics/atom_particle/proton.html&edu=elem&dev=1/moons/images/rain">protons</a>
  and heavier atomic ions. These particles get trapped in the <a
  href="/earth/Magnetosphere/earth_magnetic_field.html&edu=elem&dev=1/moons/images/rain">magnetic field of the Earth</a>. 
These belts were <a
  href="/earth/Magnetosphere/radiation_belts_discovery.html&edu=elem&dev=1/moons/images/rain">discovered</a> by James Van Allen in 1958, and so they are known as Van Allen
  Belts.<p><small><em>Courtesy of Windows to the Universe</em></small></p>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&edu=elem&dev=1/moons/images/rain">methane</a>, a powerful <a href="/earth/climate/cli_greengas.html&edu=elem&dev=1/moons/images/rain">greenhouse gas</a>.
Watch the NBC Learn video - <a href="/earth/changing_planet/permafrost_methane_intro.html&edu=elem&dev=1/moons/images/rain">Thawing Permafrost and Methane</a> to find out more.<p><small><em>Image courtesy of the    USGS</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/moons/images/rain">meteorite</a>
  at the end of the Cretaceous (at the end of the <a
  href="/earth/geology/hist_mesozoic.html&edu=elem&dev=1/moons/images/rain">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/moons/images/rain">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/moons/images/rain">massive
  volcanic eruptions</a> may be been responsible for the extinction.<p><small><em>Courtesy of Don Davis, NASA</em></small></p>Scientists at the University of Michigan have found that <a href="/earth/polar/cryosphere_permafrost1.html&edu=elem&dev=1/moons/images/rain">permafrost</a> in the <a href="/earth/polar/polar_north.html&edu=elem&dev=1/moons/images/rain">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/moons/images/rain">climate-warming</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=elem&dev=1/moons/images/rain">carbon dioxide</a>, to the <a href="/earth/Atmosphere/overview.html&edu=elem&dev=1/moons/images/rain">atmosphere</a> much faster than previously thought.<p><small><em>George Kling, The University of Michigan</em></small></p>

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