Other forms: Earths
Earth is the planet we all live on, third from the Sun in our solar system. Many astronauts say it's awe-inspiring to see Earth from outer space.
Earth is the only planet in our solar system known to harbor life. While its name is derived from the Old English eorþe, meaning "ground," about 71 percent of Earth's surface is covered with water — an essential ingredient for life as we know it. Earth orbits the Sun in the star's "habitable zone" that's not too hot or too cold. And Earth is shielded from the Sun's solar radiation by a magnetic field generated by Earth's churning iron core. Earth's oxygen-rich atmosphere also makes the planet hospitable to life.