Mercury

Earth

Earth—our home planet—is the only place we know of so far that’s inhabited by living things. It's also the only planet in our solar system with liquid water on the surface.

10 Need-to-Know Things About Our Home Planet

  • 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.

  • RINGLESS

    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.

Our home planet is the third planet from the Sun, and the only place we know of so far that’s inhabited by living things. While Earth is only the fifth largest planet in the solar system, it is the only world in our solar system with liquid water on the surface. Just slightly larger than nearby Venus, Earth is the biggest of the four planets closest to the Sun, all of which are made of rock and metal.

Namesake

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 a Germanic word, which simply means “the ground.”

Potential for Life

Earth has a very hospitable temperature and mix of chemicals that have made life abundant here. Most notably, Earth is unique in that most of our planet is covered in liquid water, since the temperature allows liquid water to exist for extended periods of time. Earth's vast oceans provided a convenient place for life to begin about 3.8 billion years ago.