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 Earth's partner in its yearly trek around the...
Exploring Our Own Back Yard The four planets closest to the Sun -- Mercury,...
Earth We know our world as an abode for life. Earth is...

Radio Programs

Close to the Sun Snuggling close to the Sun Saturday, January 3, 2015
Hailstorm The inner planets take a beating Monday, December 29, 2014
Time Bombs Time bombs in the evening sky Wednesday, April 23, 2014
Whistlers Listening for stormy skies Thursday, September 19, 2013
Water World Diving into lunar research Wednesday, July 17, 2013
Distant Sun Moving away from the Sun Friday, July 5, 2013
Young-Sun Paradox Turning up the thermostat Thursday, June 6, 2013
Changing Sun Our steadily changing Sun Wednesday, June 5, 2013
Celestial Navigation Navigating by the stars Wednesday, April 10, 2013
Magnetic Directions Navigating with an internal compass Tuesday, April 9, 2013
Magnetic Earth Earth’s changing magnetic field Monday, April 8, 2013
Zapped! Part II An outburst from a pair of dead stars Wednesday, March 27, 2013
Zapped! Earth gets zapped by cosmic radiation Tuesday, March 26, 2013
Space Watch A target in a cosmic shooting gallery Monday, February 11, 2013
Quasars IV An astronomical navigation system Friday, February 8, 2013
Distant Sun Slipping away from the Sun Wednesday, July 4, 2012
Watery Earth Raining on the young planet Earth Monday, January 9, 2012
Earth at Perihelion Snuggling close to the Sun Wednesday, January 4, 2012
December Solstice A pale light in the daytime sky Wednesday, December 21, 2011
Interstellar Skies Looking for clear interstellar skies Tuesday, November 15, 2011
Watching Earthshine Watching the dark side of the Moon Monday, September 5, 2011
Summer Solstice Hot times in northern climes Tuesday, June 21, 2011
Earth at Perihelion Soaking up some extra sunlight Monday, January 3, 2011
Moon and Jupiter Diving into longer days Sunday, December 12, 2010
Sierra Madera A drive-through impact crater Monday, August 30, 2010
Short Moon The Moon scoots by in a hurry Saturday, June 26, 2010
Summer Solstice Lighting up the start of summer Sunday, June 20, 2010

Featured Images

Supercomputer simulations of Earth's magnetic field
Twist and Flip Monday, April 8, 2013
A long-exposure view of Earth and the stars from the International Space Station
Around and Around We Go Saturday, May 26, 2012
Earth and Moon from International Space Station
Blue Moon? Monday, March 21, 2011
Sky view from space shuttle Discovery, February 2011
Nice View Wednesday, March 2, 2011
Earth is in the middle of the Sun's habitable zone
In the Zone Tuesday, January 18, 2011
Just Hanging Around Monday, January 11, 2010


©2015 The University of Texas McDonald Observatory