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.

A thick icy shell spans the surface of Europa, one of Jupiter’s moons. Beneath it lies a vast ocean — twice the volume of our planet’s — that teems with the possibility of life. This body of salt ...

Many of the most interesting bodies in our Solar System aren’t planets, but the moons that orbit them. They have active volcanoes, hydrocarbon oceans, geysers, and moon-wide oceans buried under icy ...

Stargazers could be treated to an interesting sight in the sky later this week thanks to two planets and the waning crescent moon, but will area residents be able to see it? According to EarthSky, the ...

A mere decade ago astronomers knew of just 62 moons around Saturn. Today the ringed planet boasts a staggering 274 official satellites. That’s more than any other world in the solar system—and far too ...

You may have heard a lot of online chatter about Earth's two moons recently, but that doesn't quite get the discovery right. Earth still only has one true natural satellite — our 2,159-mile-wide moon ...