Earth

Earth, our home planet, is a beautiful blue and white ball when seen from space. The third planet from the Sun, it is the largest of the inner planets. Earth is the only planet known to support life and to have liquid water at the surface. Earth has a substantial atmosphere and magnetic field, both of which are critical for sustaining life on Earth. Earth is the innermost planet in the solar system with a natural satellite – our Moon. Explore our beautiful home planet – unique in our solar system - through the links in this section.

As temperatures rise and soil moisture decreases, plants are stressed, which can lead to <a href="/earth/climate/crops_withering.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">crop withering</a>. <a href="/teacher_resources/online_courses/health/events_health.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">Droughts</a> accompanied by increased temperatures can lead to famine, social and political disruptions. Scientists are helping with early identification of drought that might trigger food shortages. Watch the NBC Learn video - <a href="/earth/changing_planet/withering_crops_intro.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">Changing Planet: Withering Crops</a> to find out more.<p><small><em>Image taken by Tomas Castelazo, Creative Commons <a href=&quot;http://creativecommons.org/licenses/by/3.0/deed.en&quot;>Attribution 3.0 Unported</a> license.</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=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">full phase</a>. Secondly, the <a href="/sun/sun.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">Sun</a>, <a href="/earth/earth.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">Earth</a> and <a href="/earth/moons_and_rings.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">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>Coral animals build reefs in warm, tropical seawater. However, <a href="/earth/changing_planet/ocean_temperatures_intro.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">seawater can be too warm</a> for their liking. If waters get too warm, coral animals lose the algae that live within their little bodies, a process called coral bleaching. Without the algae, corals have less nutrition. Unless cooler temperatures return, allowing algae to return, the coral dies.<p><small><em>Credit: UNC</em></small></p>An artist's rendering of the moment of impact of a massive <a href="/our_solar_system/meteors/meteors.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">meteorite</a> at the end of the Cretaceous (at the end of the <a href="/earth/geology/hist_mesozoic.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">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&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">mass extinction of dinosaurs</a> and many other life forms. Recent research suggests that perhaps <a href="/headline_universe/olpa/chicxulub.html&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">massive volcanic eruptions</a> may be been responsible for the extinction.<p><small><em>Courtesy of Don Davis, NASA</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><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&dev=1/images/ipcc_ar4_faq_5_1_fig_1_big.gif">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>

Explore Earth

Earth's Interior and Surface

Earth, the largest and densest rocky planet, was formed about 4.5 billion years ago. The Earth's ...Read more

Atmosphere

The atmosphere is a mixture of nitrogen (78%), oxygen (21%), and other gases (1%) that surrounds ...Read more

Magnetosphere

The Earth has a magnetic field with north and south poles. The magnetic field of the Earth ...Read more

Moon

The Earth's one natural satellite, the Moon, is more than one quarter the size of Earth itself ...Read more

Earth's Polar Regions

Do you wonder what Earth's Polar Regions are like? Where do polar bears live? Where do penguins ...Read more

Climate and Global Change

Warm near the equator and cold at the poles, our planet is able to support a variety of living ...Read more

Water (The Hydrosphere)

Water is found in many places on Earth including on the surface of the planet, within rocks ...Read more

Life and Ecology (The Biosphere)

What is life? Why is there life on Earth, but not on any other planets in the solar system ...Read more

Natural Hazards

The United Nations estimated that between 1994-2015, there were 6,873 natural disasters worldwide, ...Read more

More about Earth

Historical Events

Full Earth and Space Science    History Calendar (Members only)

Teacher Opportunities

Full Teacher Events Calendar (Educator Members only)

Did you know?

Did you know that the Earth’s magnetic field has reversed its orientation irregularly many times over Earth’s history?

Did you know that the Earth’s crust is thinner under the oceans than it is on the continents?

 

Earth and Space Science Concept of the Day

Do you know what this word or phrase means?

Cirque
xCirque : A semicircular basin excavated by glaciers in mountain top regions; may contain a lake

Click on the word to find out!

Research Highlights

Caribbean Coral Reef Protection Efforts Miss the Mark

Conservation efforts aimed at protecting endangered Caribbean corals may be overlooking regions where corals are best equipped to evolve in response to global warming and other climate challenges. That's...Read more


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