A comet from another star system will swing by Mars on Friday as a fleet of spacecraft trains its sights on the interstellar visitor. We already know a decent amount about how planets form, but moon ...

The Jovian moons Io and Europa will throw their shadows over Jupiter's cloud surface in the early hours of Nov. 5. When you purchase through links on our site, we may earn an affiliate commission.

We already know a decent amount about how planets form, but moon formation is another process entirely, and one we're not as familiar with. Scientists think they understand how the most important moon ...

Images from NASA's Galileo mission reveal a tantalizing starburst-like feature. Scientists call it a "wall demon." ...

Turn a telescope to the eastern sky in the hours following midnight on Nov. 5 to see two colossal shadows darken the cloud tops of the gas giant Jupiter as the Galilean moons Io and Europa pass ...