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.

This visual journey imagines what Jupiter, Saturn, Uranus, Neptune, and Pluto would look like from the surfaces of their ...

At a young age, we're told how the sun warms Earth and makes life possible. That idea sticks with most of us for life. But when we want to understand things more thoroughly and we dig more deeply, we ...

The object orbits a brown dwarf that orbits a star, and astronomers aren’t sure if it’s a planet, a moon — or something else ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't been for lack of trying. According to a new paper by Thomas Winterhalder of ...

Add Yahoo as a preferred source to see more of our stories on Google. An artist's impression of a habitable exomoon. (NASA GSFC/Jay Friedlander and Britt Griswold) Planets drifting unmoored through ...

For two nights, the moon will host a cosmic party with three planets – Mars, Saturn and Uranus – that will be visible in the US and beyond.

Scientists say moons around rogue planets wandering through the galaxy could remain warm enough for life thanks to tidal heating and hydrogen-rich atmospheres. These dark, starless worlds may have had ...

We have an idea of what the solar system's past was like: It was violent and chaotic. However, we are still studying how violent it was. Current models suggest that at some point after their formation ...