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

We’ve discovered thousands of exoplanets — but not a single confirmed exomoon. That doesn’t mean they aren’t out there. In fact, moons may be even more common than planets — and in some cases, even ...

The search for life beyond Earth has generally focused on places that are as much like our home as possible. That’s why the Kepler space mission has gotten headline after headline after headline in ...

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 ...

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 ...