According to a Greek legend, the sea god Poseidon placed the figure of <a href="/the_universe/Constellations/circumpolar/cassiopeia.html&edu=high&dev=">Cassiopeia</a> among the stars. It is said that Cassiopeia has a ridiculous upside-down position to punish her for having been pretentious.<p><small><em>Image courtesy of 1995 Visual Language (c). All rights reserved.</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=high&dev=">methane</a>, a powerful <a href="/earth/climate/cli_greengas.html&edu=high&dev=">greenhouse gas</a>.
Watch the NBC Learn video - <a href="/earth/changing_planet/permafrost_methane_intro.html&edu=high&dev=">Thawing Permafrost and Methane</a> to find out more.<p><small><em>Image courtesy of the    USGS</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=high&dev=">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=high&dev=">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>On November 7, 2013, Typhoon Haiyan (Yolanda in the Philippines) made landfall, with imated wind speeds of ~315 km/hr - the strongest <a href="/earth/Atmosphere/hurricane/intensity.html&edu=high&dev=">tropical cyclone</a> to make landfall in recorded history.  As Haiyan moved across the Philippines before reaching Vietnam and China, its <a href="/earth/Atmosphere/wind.html&edu=high&dev=">winds</a> and <a href="/earth/Atmosphere/hurricane/surge.html&edu=high&dev=">storm surge</a> left devastation in its wake, leading to massive loss of life, destruction of homes, and hundreds of thousands of displaced inhabitants. <a href="http://www.cnn.com/2013/11/09/world/iyw-how-to-help-typhoon-haiyan/index.html">How to Help</a><p><small><em>Image courtesy of COMS-1, SSEC, University of Wisconsin-Madison</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>This historic image is the first ever taken from a spacecraft in orbit about <a href="/mercury/mercury.html&edu=high&dev=">Mercury</a>, the innermost planet of the solar system.  Taken on 3/29/2011 by <a href="/space_missions/robotic/messenger/messenger.html&edu=high&dev=">MESSENGER</a>, it shows numerous craters across the <a href="/mercury/Interior_Surface/Surface/surface_overview.html&edu=high&dev=">surface</a> of the planet.  Temperatures there can reach over 800F because Mercury is so close to the Sun and rotates so slowly.  MESSENGER entered orbit around Mercury earlier in March 2011.<p><small><em>NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington</em></small></p>

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