What Is a Planet? (And Why Pluto Doesn't Fit the Definition) | Space
Astronomers define a planet as an object that orbits the sun (but not another object), is round (or nearly so) and has cleared the area around its orbit.| Space.com
Astronomers define a planet as an object that orbits the sun (but not another object), is round (or nearly so) and has cleared the area around its orbit.| Space.com
Earth is the only planet known to support life. Learn about what Earth is made of and where it came from.| Space
