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.

This first global map of <a href="http://www.windows2universe.org/earth/Water/ocean.html">ocean</a> surface saltiness, released in September 2012 by the NASA Aquarius mission team, shows the distribution of salt in the first 2 cm of the Earth's ocean. <a href="http://www.windows2universe.org/earth/Water/salinity.html">Salinity</a> variations are one of the main drivers of <a href="http://www.windows2universe.org/earth/Water/circulation1.html">ocean circulation</a>, and are closely connected with the <a href="http://www.windows2universe.org/earth/Water/water_cycle.html">cycling of freshwater</a> around the planet. High salinity is seen in the Mediterranean, Atlantic, and the Arabian Sea.<p><small><em>Image courtesy of NASA/GSFC/JPL-Caltech</em></small></p>This image is a montage of high resolutions photographs of the Earth taken in January 2012 by the Visible/Infrared Imager Radiometer Suite (VIIRS) instrument on the Suomi NPP satellite. The image shows many stunning details of <a href="http://www.windows2universe.org/earth/earth.html">our home planet</a> - <a href="http://solarsystem.nasa.gov/multimedia/gallery/VIIRS_4Jan2012.jpg">particularly at high resolution</a>. The beauty of our planet is obvious from space - our blue <a href="http://www.windows2universe.org/earth/Water/overview.html">waters</a>, our white <a href="http://www.windows2universe.org/earth/Atmosphere/cloud.html">clouds</a>, and the green from <a href="http://www.windows2universe.org/earth/Life/life.html">life</a> abundant at the surface.<p><small><em>Image courtesy of NASA</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/images/h/neptune/pollution_climate_change.html">methane</a>, a powerful <a href="/earth/climate/cli_greengas.html&edu=elem&dev=1/images/h/neptune/pollution_climate_change.html">greenhouse gas</a>. Watch the NBC Learn video - <a href="/earth/changing_planet/permafrost_methane_intro.html&edu=elem&dev=1/images/h/neptune/pollution_climate_change.html">Thawing Permafrost and Methane</a> to find out more.<p><small><em>Image courtesy of the USGS</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&edu=elem&dev=1/images/h/neptune/pollution_climate_change.html">full phase</a>. Secondly, the <a href="/sun/sun.html&edu=elem&dev=1/images/h/neptune/pollution_climate_change.html">Sun</a>, <a href="/earth/earth.html&edu=elem&dev=1/images/h/neptune/pollution_climate_change.html">Earth</a> and <a href="/earth/moons_and_rings.html&edu=elem&dev=1/images/h/neptune/pollution_climate_change.html">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 <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/images/h/neptune/pollution_climate_change.html">earthquake</a> and <a href="/earth/tsunami1.html&edu=elem&dev=1/images/h/neptune/pollution_climate_change.html">tsunami</a> processes. Check out the resources <a href="/teacher_resources/2011_AGU-NESTA_GIFT_Workshop.html&edu=elem&dev=1/images/h/neptune/pollution_climate_change.html">here</a>.<p><small><em>NOAA</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/images/h/neptune/pollution_climate_change.html">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>

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 most of the Earth's clouds and weather are found in lowest level of the Earth’s atmosphere?

Do you know how photosynthesis works?

 

Earth and Space Science Concept of the Day

Do you know what this word or phrase means?

Orographic lift
xOrographic lift : Occurs when an air mass is forced to rise over geographic relief from a lower elevation. As the air mass rises it expands and cools adiabatically, which can raise the relative humidity to 100%, create clouds and precipitation.

Click on the word to find out!

Research Highlights

Extended Period of Lower Solar Activity Linked to Changes in Sun's Conveyor Belt

A new analysis of the unusually long solar cycle that ended in 2008 suggests that one reason for the long cycle could be a stretching of the sun's conveyor belt, a current of plasma that circulates between...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