IntroductionEarth is the third planet from the Sun and the fifth largest in the solar system. Just slightly larger than nearby Venus, Earth is the biggest of the terrestrial planets. Our home planet is the only planet in our solar system known to harbor living things.

    The name Earth is at least 1,000 years old. All of the planets, except for Earth, were named after Greek and Roman gods and goddesses. However, the name Earth is an English/German word, which simply means the ground. Explore Earth ›

    Ten Things to Know About Earth

    Ten Things to Know About Earth


    Measuring Up

    If the Sun were as tall as a typical front door, Earth would be the size of a nickel.


    Third Rock

    Earth orbits our Sun, a star. Earth is the third planet from the Sun at a distance of about 93 million miles (150 million km).


    As the World Turns

    A day on Earth is 24 hours. Earth makes a complete orbit around the sun (a year in Earth time) in about 365 days.


    We're On It

    Earth is a rocky planet with a solid and dynamic surface of mountains, canyons, plains and more. Most of our planet is covered in water.


    Breathe Easy

    Earth's atmosphere is 78 percent nitrogen, 21 percent oxygen and 1 percent other ingredients—the perfect balance to breathe and live.


    Our Cosmic Companion

    Earth has one moon.



    Earth has no rings.


    Orbital Science

    Many orbiting spacecraft study the Earth from above as a whole system—observing the atmosphere, ocean, glaciers, and the solid earth.


    Home, Sweet Home

    Earth is the perfect place for life as we know it.


    Protective Shield

    Our atmosphere protects us from incoming meteoroids, most of which break up in our atmosphere before they can strike the surface.

    Did You Know?

    Did You Know?

    First Earthling in Space
    The first being to travel to outer space was a female part-Samoyed terrier originally named Kudryavka (Little Curly) but later renamed Laika (Barker). She weighed about 6 kg. Image Credit: National Space Science Data Center

    Laika the dog was the first Earthling to orbit Earth aboard the Soviet Union's Sputnik 2 in 1957. She did not survive the trip. A few years later, the next two Soviet space dogs—Belka and Strelka—became the first living creatures to return from space alive—paving the way for future human explorers.

    Pop Culture

    Pop Culture

    Storytellers explore the nature of our planet and possible alternate realities in many books, movies and television shows. The iconic Planet of the Apes film (and many sequels) takes place in a future in which astronauts "discover" a planet inhabited by highly intelligent apes and primitive humans, only to realize later, much to their dismay, that—spoiler alert!—it was Earth all along.

    In the long-running and re-booted television series Battlestar Galactica, tired survivors of a war with highly evolved robots called cylons are on a quest to find Earth, a long-lost colony.

    In other stories, Earth has been abandoned or destroyed, such as in the Joss Whedon series Firefly or the book and its film adaptation The Hitchhiker's Guide to the Galaxy. In the animated feature Titan A.E., Earth has been destroyed by an alien species, but a well-placed planet builder recreates it and all the species that live on it.

    Gummy Greenhouse Gases

    Gummy Greenhouse Gases Activity

    Build sweet models of the molecules of the gases that cause global warming. Eat them and save the day.



    NASA Space Place: Earth

    NASA Earth Observatory

    NASA’s Climate Portal

    NASA Earth Science Division

    Planets News