Looking for a sky event this week? Check out our full Sky This Week column. January 12: Io's post-opposition transit Point ...

On Dec. 28, 2000, NASA’s Galileo spacecraft discovered auroras on Ganymede, Jupiter’s largest moon. Galileo launched in 1989 on a mission to study Jupiter and its moons. It also flew by Venus and ...

Our solar system is a wonder, from the star at the center to the planets and moons in orbit, as seen in these fantastic pictures taken by Hubble, the Solar Dynamics Observatory, and the Mars ...