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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

Moon and Spica An important world you’ve never heard of June 27, 2023

Moon and Spica Pinpointing the position of a star May 3, 2023

More Venus and Jupiter A tug-of-war with Earth in the middle March 1, 2023

Stormy Skies Stormy Sun, stormy Earth February 16, 2023

Vaporizing Satellites Burning up the skies February 15, 2023

Getting Close Snuggling close to the Sun January 4, 2023

Earth’s Age Counting candles on a birthday cake October 12, 2022

Moon and Saturn Plunging into a deep ocean July 14, 2022

Moon and Spica Bigger Moon, warmer Earth April 15, 2022

Moon and Regulus Breaking apart Earth’s crust April 11, 2022

Death and Life Dying stars and life on Earth April 7, 2022

Dimmer Earth Earth gets a little dimmer March 28, 2022

Big Changes Rebounding after a catastrophe November 24, 2021

Rounding Off Earth Rounding off planet Earth November 17, 2021

Dangerous Flip A dangerous “flip” in a magnetic field June 7, 2021

Bubble Trouble Low tide equals more bubbles May 23, 2021

Explosive Change The possible influence of exploding stars April 9, 2021

Close to the Sun Rounding out Earth’s orbit January 1, 2021

Sunquakes A possible trigger for earthquakes October 23, 2020

Shorter Days The days keep getting longer July 30, 2020

Morning Mercury Peeling away the skin of Mercury July 22, 2020

Earth Day Looking at our own fragile planet April 22, 2020

Close to the Sun Snuggling up to the Sun January 5, 2020

Moon and Saturn A special night for Moon-watching October 5, 2019

Far From the Sun Changing the distance to the Sun July 3, 2019

Pointing North Keeping us pointed in the right direction April 5, 2019

Supernova vs. Megalodon Supernova versus Megalodon February 15, 2019

Losing Weight A “global” weight-loss plan October 18, 2018

Moon and Companions Planets that pump up Earth’s orbit September 12, 2018

Steady On Changes in Earth’s magnetic field September 4, 2018

Round Earth Rounding off planet Earth September 3, 2018

Visiting Astronomers Where to see pioneering astronomers July 22, 2018

Catching Dust Catching dust in the stratosphere June 19, 2018

Moon and Aldebaran Moving the Moon across the sky January 26, 2018

Extremophiles Life in the most unlikely of places November 24, 2017

Far from the Sun Circling far from the Sun July 3, 2017

On the Move Racing across the universe June 10, 2017

Hydrothermal Vents A starting point in the search for life February 17, 2017

Moon and Planets Earth and the Moon move around January 3, 2017

Featured Images

artist's concept of van allen radiation belts

Danger Zone April 24, 2023

Close Companions April 15, 2022

Shorter Days July 30, 2020

Earthrise above the Moon, Apollo 8, December 24, 1968

Pale Blue Marble April 22, 2020

Grand Prismatic Spring, Yellowstone National Park

Extreme Life November 24, 2017

Combined X-ray and optical image of a supernova remnant

Zone of Death August 31, 2017

Cassini view of Earth, Moon, and Saturn's rings

Looking Back April 24, 2017

Artist's concept of Earth's distant future

Bright Future April 29, 2015