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.

The massive 9.0 magnitude <a href="/earth/geology/quake_1.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">earthquake</a> off of Honshu, Japan on <a href="/headline_universe/march112011earthquaketsunami.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">11 March 2011</a> generated a <a href="/earth/tsunami1.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">tsunami</a> that exceeded 10 meters on the coast near the epicenter.  This image shows model projections for the tsunami wave height in cm which are in good agreement with the observed waves. Our thoughts and prayers are with those who were lost, and their families, as we remember this event.<p><small><em><a href="http://blogs.agu.org/wildwildscience/files/2011/03/680_20110311-TsunamiWaveHeight.jpg">NOAA Tsunami Wave Height Projections image</a></em></small></p>Sinkholes are <a href="/teacher_resources/main/frameworks/esl_bi8.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">natural hazards</a> in many places around the world. They are formed when water dissolves underlying <a href="/earth/Water/carbonates.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">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>As temperatures rise and soil moisture decreases, plants are stressed, which can lead to <a href="/earth/climate/crops_withering.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">crop withering</a>. <a href="/teacher_resources/online_courses/health/events_health.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">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&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">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>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&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">methane</a>, a powerful <a href="/earth/climate/cli_greengas.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">greenhouse gas</a>.
Watch the NBC Learn video - <a href="/earth/changing_planet/permafrost_methane_intro.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">Thawing Permafrost and Methane</a> to find out more.<p><small><em>Image courtesy of the    USGS</em></small></p>A new study has found that <a href="/earth/Atmosphere/airpollution_intro.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">pollution</a> from <a href="/earth/Atmosphere/particulates.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">fine particles</a> in the air - mainly the result of burning coal or <a href="/earth/interior/eruptions.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">volcanic eruptions</a> - can shade <a href="/earth/Life/cnidarian.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">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>A view of the Earth as seen by the <a href="/space_missions/apollo17.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">Apollo
17</a> crew
while traveling to the
<a href="/earth/moons_and_rings.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">Moon</a> on
December 7, 1972.  Africa, Madagascar, and the Arabian Peninsula are
visible, and you can barely make out the
<a href="/earth/polar/antarctica.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">Antarctic</a>,
shrouded in the heavy
<a href="/earth/Atmosphere/cloud.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">cloud</a> cover
in the southern hemisphere.
Arching cloud patterns show the presence of <a href="/earth/Atmosphere/front.html&dev=1/moons/images/h/neptune/=/earth/climate/ASCL_Workshop.pps">weather
fronts</a>.<p><small><em>Image courtesy of NASA/Apollo 17.</em></small></p>

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