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Our home planet, the third from the Sun in the solar system. The Earth orbits the Sun at an average distance of 93 million miles (149 million km/1 astronomical unit) and has a mass of 6x10^24 kg. It is made of solid, rocky materials such as iron, nickel, and silicon, and it has an atmosphere composed mainly of nitrogen and oxygen with traces of argon, carbon dioxide, and other compounds. Liquid water covers 71 percent of the planet’s surface. Earth has one moon.


Earth’s Moon February 19, 2016


Earth February 10, 2016

Radio Programs

Heating Up Heating up the young Earth September 23, 2016

New Helium A common but hard-to-find element September 10, 2016

Iron Rain Showering Earth with iron raindrops August 17, 2015

Noctilucent Clouds Electric-blue clouds in the twilight July 26, 2015

Leap Second Stretching out the month of June June 29, 2015

Second Generation A second generation of planets June 7, 2015

Oceans Gained Filling up Earth’s oceans June 4, 2015

Meteorites II Measuring the age of the solar system April 17, 2015

Twin Monsters Giving life to a classic story April 4, 2015

Close to the Sun Snuggling close to the Sun January 2, 2015

Hailstorm The inner planets take a beating December 28, 2014

Time Bombs Time bombs in the evening sky April 22, 2014

Whistlers Listening for stormy skies September 18, 2013

Water World Diving into lunar research July 16, 2013

Distant Sun Moving away from the Sun July 4, 2013

Young-Sun Paradox Turning up the thermostat June 5, 2013

Changing Sun Our steadily changing Sun June 4, 2013

Celestial Navigation Navigating by the stars April 9, 2013

Magnetic Directions Navigating with an internal compass April 8, 2013

Magnetic Earth Earth’s changing magnetic field April 7, 2013

Zapped! Part II An outburst from a pair of dead stars March 26, 2013

Zapped! Earth gets zapped by cosmic radiation March 25, 2013

Space Watch A target in a cosmic shooting gallery February 10, 2013

Quasars IV An astronomical navigation system February 7, 2013

Distant Sun Slipping away from the Sun July 3, 2012

Watery Earth Raining on the young planet Earth January 8, 2012

Earth at Perihelion Snuggling close to the Sun January 3, 2012

December Solstice A pale light in the daytime sky December 20, 2011

Interstellar Skies Looking for clear interstellar skies November 14, 2011

Watching Earthshine Watching the dark side of the Moon September 4, 2011

Summer Solstice Hot times in northern climes June 20, 2011

Earth at Perihelion Soaking up some extra sunlight January 3, 2011

Featured Images

Artist's concept of Earth's distant future

Bright Future April 29, 2015

Supercomputer simulations of Earth's magnetic field

Twist and Flip April 8, 2013

Earth and Moon from International Space Station

Blue Moon? March 21, 2011

Sky view from space shuttle Discovery, February 2011

Nice View March 2, 2011

Earth is in the middle of the Sun's habitable zone

In the Zone January 18, 2011

Just Hanging Around January 11, 2010