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.

This composite image of Earth and its moon, as seen from Mars, combines the best Earth image with the best moon image from four sets of images acquired on Nov. 20, 2016, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.

On Oct. 9, NASA's Juno spacecraft flew past Earth, using our home planet's gravity to get the final boost it needed to reach Jupiter. The JunoCam instrument captured this monochrome view of Earth, and other instruments were tested to ensure they work as designed during a close planetary encounter.

This view of the twilight sky and Martian horizon taken by NASA's Curiosity Mars rover includes Earth as the brightest point of light in the night sky.

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THE THINGS NEED-TO-KNOW ABOUT EARTH

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MEASURING UP

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

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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).

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ORBITAL SCIENCE

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

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PROTECTIVE SHIELD

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

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BREATHE EASY

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

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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.