An artist's rendering of the moment of impact of a massive <a href="/our_solar_system/meteors/meteors.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">meteorite</a> at the end of the Cretaceous (at the end of the <a href="/earth/geology/hist_mesozoic.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">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&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">mass extinction of dinosaurs</a> and many other life forms. Recent research suggests that perhaps <a href="/headline_universe/olpa/chicxulub.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">massive volcanic eruptions</a> may be been responsible for the extinction.<p><small><em>Courtesy of Don Davis, NASA</em></small></p><p>Something on Earth is always burning! NASA's Earth Observatory tracks wildfires across the world with <a href="http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD14A1_M_FIRE" target="_blank">maps available for viewing</a> from 2000-present. Some wildfires can restore <a href="/earth/ecosystems.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">ecosystems</a> to good health, but many can threaten human populations, posing a natural disaster threat.</p> <p>Check out the materials about natural disasters in <a href="/earth/natural_hazards/when_nature_strikes.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">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>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>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>The massive 9.0 magnitude <a href="/earth/geology/quake_1.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">earthquake</a> off of Honshu, Japan on <a href="/headline_universe/march112011earthquaketsunami.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">11 March 2011</a> generated a <a href="/earth/tsunami1.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">tsunami</a> that exceeded 10 meters on the coast near the epicenter. This image shows model projections for the tsunami wave height in cm which are in good agreement with the observed waves. Our thoughts and prayers are with those who were lost, and their families, as we remember this event.<p><small><em><a href="http://blogs.agu.org/wildwildscience/files/2011/03/680_20110311-TsunamiWaveHeight.jpg">NOAA Tsunami Wave Height Projections image</a></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=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">methane</a>, a powerful <a href="/earth/climate/cli_greengas.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">greenhouse gas</a>. Watch the NBC Learn video - <a href="/earth/changing_planet/permafrost_methane_intro.html&edu=elem&dev=1/k=/h/neptune/=/wildlife_forests.html">Thawing Permafrost and Methane</a> to find out more.<p><small><em>Image courtesy of the USGS</em></small></p>


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Scientists Study "Glaciovolcanoes," Mountains of Fire and Ice

Scientists can learn a lot about Earth's past climates from the deposits of glaciovolcanoes like Eyjafjallajökull in Iceland ...Read more
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CMMAP - Studying Clouds and Climate

Clouds are an important part of Earth's weather and climate. Scientists use computer models to study our planet's climate ...Read more
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Animations, images, and videos portraying space weather and solar activity. Watch sunspots form and see aurora shimmer and dance across the skies ...Read more
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Genetics Makes Us Who We Are

Some characteristics, or traits, result from interactions with the environment, others are determined from the genetic material in your chromosomes ...Read more

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Mars, the Red Planet, is like Earth in many ways. Mars has huge volcanoes, gigantic canyons, and polar ice caps. The fourth planet from the Sun, Mars is smaller, colder, and drier than Earth ...Read more

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Impact on Jupiter - July 2009

Anthony Wesley is an astronomer in Australia. One night in July 2009, Wesley noticed a dark spot on Jupiter...Read more


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