Unlike our Moon, they can keep water in oceans liquid for more than 4 billion years.

When we imagine alien life in books or on TV, we often think of planets like ours inhabited by extraterrestrial people. The Harry Vanderspeigle’s (Alan Tudyk) of the universe are basically human with ...

Beneath Triton’s frozen surface, scientists believe a vast subsurface ocean may exist. If confirmed, this distant moon could ...

Add Yahoo as a preferred source to see more of our stories on Google. This artist’s concept depicts a potential volcanic exomoon between the exoplanet WASP-49Ab, left, and its parent star.

For the first time, scientists have directly detected molecules in a Frisbee of gas and dust swirling around an alien gas-giant planet. “I didn’t think this was possible,” says astronomer Sierra Grant ...

If you examine our solar system’s giant planets, you’ll notice right away that they’ve all got moons—a lot of moons. While Earth only has the one, Jupiter has about 100 that we know of (and likely ...