How did life evolve on <a href="/earth/earth.html&dev=">Earth</a> during the <a href="/earth/past/Archean.html&dev=">Archean</a>, when the <a href="/sun/sun.html&dev=">Sun</a> was about 25% weaker than today?  The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html&dev=">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html&dev=">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&dev=">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html&dev=">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html&dev=">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html&dev=">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html&dev=">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</em></small></p>Anti-crepuscular rays are beams of sunlight that appear to converge on a point opposite the sun. They are similar to crepuscular rays, but are seen opposite the sun in the sky. Anti-crepuscular rays are most frequently visible near sunrise or sunset. This photo of anti-crepuscular rays was taken at sunset in Boulder, Colorado. Crepuscular rays are usually much brighter than anti-crepuscular rays.<p><small><em> Image Courtesy of Carlye Calvin</em></small></p>Scientists at the University of Michigan have found that <a href="/earth/polar/cryosphere_permafrost1.html&dev=">permafrost</a> in the <a href="/earth/polar/polar_north.html&dev=">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&dev=">climate-warming</a> <a href="/physical_science/chemistry/carbon_dioxide.html&dev=">carbon dioxide</a>, to the <a href="/earth/Atmosphere/overview.html&dev=">atmosphere</a> much faster than previously thought.<p><small><em>George Kling, The University of Michigan</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&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&dev=">winds</a> and <a href="/earth/Atmosphere/hurricane/surge.html&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>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&dev=">full phase</a>. Secondly, the <a href="/sun/sun.html&dev=">Sun</a>, <a href="/earth/earth.html&dev=">Earth</a> and <a href="/earth/moons_and_rings.html&dev=">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>According to <a href="http://www.jpl.nasa.gov/news/news.php?release=2013-277">NASA scientists</a>, the Voyager 1 spacecraft entered interstellar space in August 2012, becoming the first spacecraft to leave the <a href="/our_solar_system/solar_system.html&dev=">solar system</a>. The space probe is about 19 billion km from the <a href="/sun/sun.html&dev=">Sun</a>.  <a href="/space_missions/voyager.html&dev=">Voyager 1 and 2</a> were launched in 1977 on a <a href="/space_missions/voyager.html&dev=">mission</a> that flew them both by <a href="/jupiter/jupiter.html&dev=">Jupiter</a> and <a href="/saturn/saturn.html&dev=">Saturn</a>, with Voyager 2 continuing to <a href="/uranus/uranus.html&dev=">Uranus</a> and <a href="/neptune/neptune.html&dev=">Neptune</a>. Voyager 2 is the longest continuously operated spacecraft. It is about 15 billion km away from the <a href="/sun/sun.html&dev=">Sun</a>.<p><small><em>Image courtesy of NASA</em></small></p>

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