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.

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=high&dev=1">full phase</a>. Secondly, the <a href="/sun/sun.html&edu=high&dev=1">Sun</a>, <a href="/earth/earth.html&edu=high&dev=1">Earth</a> and <a href="/earth/moons_and_rings.html&edu=high&dev=1">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><p>Something on Earth is always burning! NASA's Earth Observatory tracks wildfires across the world with <a href="http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD14A1_M_FIRE" target="_blank">maps available for viewing</a> from 2000-present. Some wildfires can restore <a href="/earth/ecosystems.html&edu=high&dev=1">ecosystems</a> to good health, but many can threaten human populations, posing a natural disaster threat.</p>
<p>Check out the materials about natural disasters in <a href="/earth/natural_hazards/when_nature_strikes.html&edu=high&dev=1">NBC Learn Videos</a>, and their earth system science connections built up by the related secondary classroom activities.</p><p><small><em>NBC Learn</em></small></p>An <a href="http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc000905e.php">8.6 magnitude earthquake</a> struck on 11 April 2012 off of Banda Aceh, Sumatra, Indonesia, followed by a strong aftershock.  Earthquake motion was primarily horizontal.  A tsunami warning was issued for the Indian Ocean, but was cancelled at 12:36 UTC.  A tsunami was observed at 1 meter or less. Find out more about <a href="/earth/geology/quake_1.html&edu=high&dev=1">earthquake</a> and <a href="/earth/tsunami1.html&edu=high&dev=1">tsunami</a> processes. Check out the resources <a href="/teacher_resources/2011_AGU-NESTA_GIFT_Workshop.html&edu=high&dev=1">here</a>.<p><small><em>NOAA</em></small></p>A view of the Earth as seen by the <a href="/space_missions/apollo17.html&edu=high&dev=1">Apollo
17</a> crew
while traveling to the
<a href="/earth/moons_and_rings.html&edu=high&dev=1">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&edu=high&dev=1">Antarctic</a>,
shrouded in the heavy
<a href="/earth/Atmosphere/cloud.html&edu=high&dev=1">cloud</a> cover
in the southern hemisphere.
Arching cloud patterns show the presence of <a href="/earth/Atmosphere/front.html&edu=high&dev=1">weather
fronts</a>.<p><small><em>Image courtesy of NASA/Apollo 17.</em></small></p>March 2012 marks the first anniversary of the 9.0 magnitude <a href="/earth/geology/quake_1.html&edu=high&dev=1">earthquake</a>, <a href="/earth/tsunami1.html&edu=high&dev=1">tsunami</a>, and resulting nuclear accident in Japan on <a href="/headline_universe/march112011earthquaketsunami.html&edu=high&dev=1">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=high&dev=1">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=high&dev=1">magnetosphere</a>. The radiation belts of the Earth are made up of <a
  href="/physical_science/physics/atom_particle/electron.html&edu=high&dev=1">electrons</a>,
<a
  href="/physical_science/physics/atom_particle/proton.html&edu=high&dev=1">protons</a>
  and heavier atomic ions. These particles get trapped in the <a
  href="/earth/Magnetosphere/earth_magnetic_field.html&edu=high&dev=1">magnetic field of the Earth</a>. 
These belts were <a
  href="/earth/Magnetosphere/radiation_belts_discovery.html&edu=high&dev=1">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>

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA