Shop Windows to the Universe

Dig into Montana Before History: 11K Years of Hunter-Gatherers in the Rockies and Plains by D. H. MacDonald, Ph.D. See our online store book collection.

Earth's Atmosphere

The atmosphere is a mixture of nitrogen (78%), oxygen (21%), and other gases (1%) that surrounds Earth. High above the planet, the atmosphere becomes thinner until it gradually reaches space. It is divided into five layers. Most of the weather and clouds are found in the first layer.

The atmosphere is an important part of what makes Earth livable. It blocks some of the Sun's dangerous rays from reaching Earth. It traps heat, making Earth a comfortable temperature. And the oxygen within our atmosphere is essential for life.

Over the past century, greenhouse gases and other air pollutants released into the atmosphere have been causing big changes like global warming, ozone holes, and acid rain.

<a
  href="/earth/Atmosphere/tstorm/tstorm_lightning.html&edu=high&dev=1">Lightning</a>
  is the most spectacular element of a <a
  href="/earth/Atmosphere/tstorm.html&edu=high&dev=1">thunderstorm</a>.
  A single stroke of lightning can <a
  href="/earth/Atmosphere/temperature.html&edu=high&dev=1">heat</a>
  the air around it to 30,000 degrees Celsius (54,000 degrees Fahrenheit)! This
  extreme heating causes the air to expand explosively. The expansion creates a
  shock wave that turns into a booming <a
  href="/earth/Atmosphere/tstorm/lightning_thunder.html&edu=high&dev=1">sound
  wave</a>, better known as thunder.<p><small><em> Image Courtesy of University Corporation for Atmospheric Research/Carlye Calvin</em></small></p>How did life evolve on <a href="/earth/earth.html&edu=high&dev=1">Earth</a> during the <a href="/earth/past/Archean.html&edu=high&dev=1">Archean</a>, when the <a href="/sun/sun.html&edu=high&dev=1">Sun</a> was about 25% weaker than today?  The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html&edu=high&dev=1">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html&edu=high&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=high&dev=1">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html&edu=high&dev=1">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html&edu=high&dev=1">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html&edu=high&dev=1">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=high&dev=1">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</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=1">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=1">winds</a> and <a href="/earth/Atmosphere/hurricane/surge.html&edu=high&dev=1">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>Does Earth science matter?  The power outage experienced by residents in New York City on 10/30/2012 due to Hurricane Sandy demonstrates the interconnectedness of our society, and the power of the Earth system.  Every person should have an understanding of how the Earth system works so they can live better lives, protect those they love, and make wise choices.  Earth science education is critical!<p><small><em>Image courtesy of Hybirdd, licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license.</em></small></p><a
  href="/earth/Atmosphere/clouds/lenticular.html&edu=high&dev=1">Lenticular
  clouds</a> form on the downwind side of mountains. <a
  href="/earth/Atmosphere/wind.html&edu=high&dev=1">Wind</a>
  blows most types of clouds across the sky, but lenticular clouds seem to stay
  in one place. Air moves up and over a mountain, and at the point where the
  air goes past the mountaintop the lenticular cloud forms, and then the air <a
  href="/earth/Water/evaporation.html&edu=high&dev=1">evaporates</a>
  on the side farther away from the mountains.  This close up of lenticular
  clouds was taken at sunset on November 20, 2006 in Boulder, Colorado.<p><small><em>       Courtesy of Roberta Johnson</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>

Windows to the Universe Community

News

Opportunities


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