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.

Scientists are concerned that melting Arctic sea ice will increase the amount of fresh water in the <a href="/earth/polar/arctic_currents.html&edu=elem&dev=1/visibility.html">Beaufort Gyre</a>, which could spill out into the Atlantic and cause major climate shifts in North America and Western Europe. Watch the <a href="/earth/changing_planet/freshwater_arctic.html&edu=elem&dev=1/visibility.html">Changing Planet: Fresh Water in the Arctic video</a>.<p><small><em> Courtesy of Jack Cook, WHOI (<a href="http://www.whoi.edu">Woods Hole Oceanographic Institute</a>)</em></small></p>This iconic image of Earth rising above the surface of the <a href="/earth/moons_and_rings.html&edu=elem&dev=1/visibility.html">Moon</a>, was taken on December 24, 1968 by astronauts on the <a href="/space_missions/apollo8.html&edu=elem&dev=1/visibility.html">Apollo 8 mission</a>. Apollo 8 was the first <a href="/space_missions/manned.html&edu=elem&dev=1/visibility.html">manned mission</a> to the Moon, and entered into lunar orbit on Christmas Eve. That evening, the astronauts held a live broadcast from lunar orbit, in which they showed pictures of the Earth and moon as seen from their spacecraft.<p><small><em> Image courtesy of NASA</em></small></p>How did life evolve on <a href="/earth/earth.html&edu=elem&dev=1/visibility.html">Earth</a> during the <a href="/earth/past/Archean.html&edu=elem&dev=1/visibility.html">Archean</a>, when the <a href="/sun/sun.html&edu=elem&dev=1/visibility.html">Sun</a> was about 25% weaker than today? The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html&edu=elem&dev=1/visibility.html">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html&edu=elem&dev=1/visibility.html">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=elem&dev=1/visibility.html">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html&edu=elem&dev=1/visibility.html">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html&edu=elem&dev=1/visibility.html">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html&edu=elem&dev=1/visibility.html">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=elem&dev=1/visibility.html">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</em></small></p>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><p>You don't normally see <a href="/space_weather/space_weather.html&edu=elem&dev=1/visibility.html">space weather</a> forecasted on the evening news, but it does impact life on <a href="/earth/earth.html&edu=elem&dev=1/visibility.html">Earth</a> in many ways. What are the threats posed from all of these natural disasters and how can we work to mitigate those threats beforehand? </p> <p>Check out the materials about natural disasters in <a href="/earth/natural_hazards/when_nature_strikes.html&edu=elem&dev=1/visibility.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>A view of the Earth as seen by the <a href="/space_missions/apollo17.html&edu=elem&dev=1/visibility.html">Apollo 17</a> crew while traveling to the <a href="/earth/moons_and_rings.html&edu=elem&dev=1/visibility.html">Moon</a> on December 7, 1972. Africa, Madagascar, and the Arabian Peninsula are visible, and you can barely make out the <a href="/earth/polar/antarctica.html&edu=elem&dev=1/visibility.html">Antarctic</a>, shrouded in the heavy <a href="/earth/Atmosphere/cloud.html&edu=elem&dev=1/visibility.html">cloud</a> cover in the southern hemisphere. Arching cloud patterns show the presence of <a href="/earth/Atmosphere/front.html&edu=elem&dev=1/visibility.html">weather fronts</a>.<p><small><em>Image courtesy of NASA/Apollo 17.</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 Polar Regions of the Earth have unique forms of life adapted to extreme environments?

Do you know what caused the "Year Without a Summer"?

 

Earth and Space Science Concept of the Day

Do you know what this word or phrase means?

Pleistocene
xPleistocene : The time period between about 10,000 years before present and about 1,650,000 years before present.

Click on the word to find out!

Research Highlights

New Computer Model Advances Climate Change Research

Scientists can now study climate change in far more detail with powerful new computer software released by the National Center for Atmospheric Research (NCAR) in Boulder, Colo. The Community Earth System...Read more


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