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 ...

Here's how the astronomical phenomenon influences our planet—from the length of our seasons to the way Earth moves through ...

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 ...

If you extend a line from your fingertip all the way through the Earth, that line would point in the direction of “up” to ...

The star system V1298 Tau reveals that many planets begin as large, low-density worlds that slowly shrink and shed their ...

Pluto, once considered the ninth planet, was reclassified as a dwarf planet in 2006 because it shares its orbital path with ...

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 ...

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 ...

Mercury has long baffled astronomers because it defies much of what we know about planet formation. A new space mission arriving in 2026 might solve the mystery.