Why don't planets fall into the stars they orbit if they're constantly being pulled by gravity?Lindsey CoughterRocky Mount, ...

The International Astronomical Union defines a planet as a celestial body that orbits the sun, is massive enough that gravity has forced it into a spherical shape, and has cleared away other objects ...

At half the size of Earth and one-tenth its mass, Mars is a featherweight as far as planets go. Yet new research reveals the ...

Pluto sits far out in the Solar System, small and dim, moving at a pace that barely fits human timelines. It was found in ...

In the cold, dark outskirts of planetary systems far beyond the reach of the known planets, mysterious gas giants and planetary masses silently orbit their stars—sometimes thousands of astronomical ...

Thanks to the discovery of thousands of exoplanets to date, we know that planets bigger than Earth but smaller than Neptune ...

Pluto's days, though they drag on a bit at around 153 hours, are nothing compared to its years. Pluto's orbit takes 248 Earth ...

Astronomers have detected a rogue planet roughly the size of Saturn wandering alone through the Milky Way. Unlike most ...