Although astronomers have found thousands of exoplanets, the number of confirmed exomoons—and exorings—is still zero. But ...

If our Moon suddenly vanished, Earth would already face dramatic consequences. But replacing it with entire alien worlds ...

We’ve discovered thousands of exoplanets — but not a single confirmed exomoon. That doesn’t mean they aren’t out there. In ...

The team of astronomers behind the find suggested it could help us better understand planet and moon formation in our solar system and beyond the Milky Way. The team was able to make the first-ever ...

What is the difference between a moon and a planet? Trick question! According to scientific definitions, there often isn’t much of a difference at all. That might seem counterintuitive, but it’s true.

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 ...

Mercury, Venus, Neptune, Saturn, Uranus and Jupiter will appear together shortly after sunset on Feb. 28 — but is this the "planet parade" we've been waiting for?

Life may not get blasted off any of the known "super-Earth" worlds as readily as it can from our planet, scientists find. The discovery suggests that any intelligent aliens that develop on such ...