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Our Glaciers: Then and Now activity kit helps you see the changes taking place in glaciers around the world. See all our activity kits and classroom activities.

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.

This is an artist's conception of the
  Earth and the inner and outer <a
  href="/glossary/radiation_belts.html&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&dev=1">magnetosphere</a>. The radiation belts of the Earth are made up of <a
  href="/physical_science/physics/atom_particle/electron.html&dev=1">electrons</a>,
<a
  href="/physical_science/physics/atom_particle/proton.html&dev=1">protons</a>
  and heavier atomic ions. These particles get trapped in the <a
  href="/earth/Magnetosphere/earth_magnetic_field.html&dev=1">magnetic field of the Earth</a>. 
These belts were <a
  href="/earth/Magnetosphere/radiation_belts_discovery.html&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>An image of Hurricane Sandy taken by the GOES-13 satellite on October 28.  This category 1 <a href="/earth/Atmosphere/hurricane/hurricane.html&dev=1">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>This first global map of <a href="http://www.windows2universe.org/earth/Water/ocean.html">ocean</a> surface saltiness, released in September 2012 by the NASA Aquarius mission team, shows the distribution of salt in the first 2 cm of the Earth's ocean. <a href="http://www.windows2universe.org/earth/Water/salinity.html">Salinity</a> variations are one of the main drivers of <a href="http://www.windows2universe.org/earth/Water/circulation1.html">ocean circulation</a>, and are closely connected with the <a href="http://www.windows2universe.org/earth/Water/water_cycle.html">cycling of freshwater</a> around the planet. High salinity is seen in the Mediterranean, Atlantic, and the Arabian Sea.<p><small><em>Image courtesy of NASA/GSFC/JPL-Caltech</em></small></p>Greenland’s <a href="http://www.windows2universe.org/earth/polar/cryosphere_glacier1.html">ice sheet</a> saw a record <a href="http://www.windows2universe.org/headline_universe/olpa/greenland_10dec07.html">melt</a> in July 2012.  Scientists studying this event have found that this melting event was triggered by an influx of unusually warm air and amplified by the presence of a blanket of thin low-level <a href="http://www.windows2universe.org/earth/Atmosphere/cloud.html">clouds</a> which pushed temperatures up above freezing.  For more information see the <a href="http://www.news.wisc.edu/21638">press release</a> from the University of Wisconsin Madison.<p><small><em>Image courtesy of University of Wisconsin-Madison</em></small></p>Coral animals build reefs in warm, tropical seawater. However, <a href="/earth/changing_planet/ocean_temperatures_intro.html&dev=1">seawater can be too warm</a> for their liking.  If waters get too warm, coral animals lose the algae that live within their little bodies, a process called coral bleaching. Without the algae, corals have less nutrition. Unless cooler temperatures return, allowing algae to
 return, the coral dies.<p><small><em>Credit: UNC</em></small></p>An artist's rendering of the moment of impact of a massive <a
  href="/our_solar_system/meteors/meteors.html&dev=1">meteorite</a>
  at the end of the Cretaceous (at the end of the <a
  href="/earth/geology/hist_mesozoic.html&dev=1">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&dev=1">mass extinction
  of dinosaurs</a> and many other life forms.  Recent research suggests that
 perhaps <a
  href="/headline_universe/olpa/chicxulub.html&dev=1">massive
  volcanic eruptions</a> may be been responsible for the extinction.<p><small><em>Courtesy of Don Davis, NASA</em></small></p>

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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