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">full phase</a>. Secondly, the <a href="/sun/sun.html&edu=elem&dev=1">Sun</a>, <a href="/earth/earth.html&edu=elem&dev=1">Earth</a> and <a href="/earth/moons_and_rings.html&edu=elem&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>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">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>There are over 900 <a href="/the_universe/uts/megalith.html&edu=elem&dev=1">rings of stone</a> located in the British Isles. The most famous of these stone rings is of course, <a href="/the_universe/uts/stonehenge.html&edu=elem&dev=1">Stonehenge</a>.    The stones of Stonehenge were put in place between 3,000 B.C and 2,000 B.C. by neolithic people.Some speculate that the site was built as a temple of worship of the ancient Earth deities. Some say it was used as an <a href="/the_universe/uts/stonehenge_astro.html&edu=elem&dev=1">astronomical observatory</a> of sorts. Still others say it was a burial ground.<p><small><em>  Image courtesy of Corel Photography.</em></small></p>How did life evolve on <a href="/earth/earth.html&edu=elem&dev=1">Earth</a> during the <a href="/earth/past/Archean.html&edu=elem&dev=1">Archean</a>, when the <a href="/sun/sun.html&edu=elem&dev=1">Sun</a> was about 25% weaker than today?  The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html&edu=elem&dev=1">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html&edu=elem&dev=1">greenhouse</a> gas concentration was the same as today.  <a href="http://www.manchester.ac.uk/aboutus/news/display/?id=10798">Researchers</a> studying the <a href="/physical_science/physics/atom_particle/isotope.html&edu=elem&dev=1">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html&edu=elem&dev=1">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html&edu=elem&dev=1">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html&edu=elem&dev=1">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=elem&dev=1">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</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=elem&dev=1">earthquake</a> and <a href="/earth/tsunami1.html&edu=elem&dev=1">tsunami</a> processes. Check out the resources <a href="/teacher_resources/2011_AGU-NESTA_GIFT_Workshop.html&edu=elem&dev=1">here</a>.<p><small><em>NOAA</em></small></p><p>The United Nations <a href="http://reliefweb.int/sites/reliefweb.int/files/resources/PAND_report.pdf" target="_blank">estimated</a> that between 1994-2015, there were 6,873 natural disasters worldwide, which affected 218 million people and claimed 1.35 million lives. </p>
<p>Check out the materials about natural disasters in <a href="/earth/natural_hazards/when_nature_strikes.html&edu=elem&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>

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