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=elem&dev=1/k=/teacher_resources/rain">full phase</a>. Secondly, the <a href="/sun/sun.html&edu=elem&dev=1/k=/teacher_resources/rain">Sun</a>, <a href="/earth/earth.html&edu=elem&dev=1/k=/teacher_resources/rain">Earth</a> and <a href="/earth/moons_and_rings.html&edu=elem&dev=1/k=/teacher_resources/rain">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 image is a montage of high resolutions photographs of the Earth taken in January 2012 by the Visible/Infrared Imager Radiometer Suite (VIIRS) instrument on the Suomi NPP satellite.  The image shows many stunning details of <a href="http://www.windows2universe.org/earth/earth.html">our home planet</a> - <a href="http://solarsystem.nasa.gov/multimedia/gallery/VIIRS_4Jan2012.jpg">particularly at high resolution</a>. The beauty of our planet is obvious from space - our blue <a href="http://www.windows2universe.org/earth/Water/overview.html">waters</a>, our white <a href="http://www.windows2universe.org/earth/Atmosphere/cloud.html">clouds</a>, and the green from <a href="http://www.windows2universe.org/earth/Life/life.html">life</a> abundant at the surface.<p><small><em>Image courtesy of NASA</em></small></p>Scientists at the University of Michigan have found that <a href="/earth/polar/cryosphere_permafrost1.html&edu=elem&dev=1/k=/teacher_resources/rain">permafrost</a> in the <a href="/earth/polar/polar_north.html&edu=elem&dev=1/k=/teacher_resources/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/k=/teacher_resources/rain">climate-warming</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=elem&dev=1/k=/teacher_resources/rain">carbon dioxide</a>, to the <a href="/earth/Atmosphere/overview.html&edu=elem&dev=1/k=/teacher_resources/rain">atmosphere</a> much faster than previously thought.<p><small><em>George Kling, The University of Michigan</em></small></p>An image of Hurricane Sandy taken by the GOES-13 satellite on October 28.  This category 1 <a href="/earth/Atmosphere/hurricane/hurricane.html&edu=elem&dev=1/k=/teacher_resources/rain">hurricane</a> was huge, spanning a horizontal distance of about one-third the US continental landmass.  The storm came onshore in New Jersey, and gradually moved northeast.  The storm disrupted the lives of tens of millions in the eastern US, doing billions of dollars in damage, resulting in over 30 deaths.  Visit the National Hurricane Center's webpage on <a href="http://www.nhc.noaa.gov/">Hurricane Sandy</a> for details.<p><small><em>Image courtesy of NASA</em></small></p>Scientists are concerned that melting Arctic sea ice will increase the amount of fresh water in the <a href="/earth/polar/arctic_currents.html&edu=elem&dev=1/k=/teacher_resources/rain">Beaufort Gyre</a>, which could spill out into the Atlantic and cause major climate shifts in North America and Western Europe. Watch the <a href="/earth/changing_planet/freshwater_arctic.html&edu=elem&dev=1/k=/teacher_resources/rain">Changing Planet: Fresh Water in the Arctic video</a>.<p><small><em> Courtesy of Jack Cook, WHOI (<a href="http://www.whoi.edu">Woods Hole Oceanographic Institute</a>)</em></small></p>A view of the Earth as seen by the <a href="/space_missions/apollo17.html&edu=elem&dev=1/k=/teacher_resources/rain">Apollo
17</a> crew
while traveling to the
<a href="/earth/moons_and_rings.html&edu=elem&dev=1/k=/teacher_resources/rain">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=elem&dev=1/k=/teacher_resources/rain">Antarctic</a>,
shrouded in the heavy
<a href="/earth/Atmosphere/cloud.html&edu=elem&dev=1/k=/teacher_resources/rain">cloud</a> cover
in the southern hemisphere.
Arching cloud patterns show the presence of <a href="/earth/Atmosphere/front.html&edu=elem&dev=1/k=/teacher_resources/rain">weather
fronts</a>.<p><small><em>Image courtesy of NASA/Apollo 17.</em></small></p>

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