Looking for a sky event this week? Check out our full Sky This Week column. January 12: Io's post-opposition transit Point your telescope at bright Jupiter in Gemini to catch a transit of the large ...

Add Yahoo as a preferred source to see more of our stories on Google. On Dec. 28, 2000, NASA’s Galileo spacecraft discovered auroras on Ganymede, Jupiter’s largest moon. Galileo launched in 1989 ...

Jupiter’s moon Ganymede could be a vast dark matter detector, and upcoming space missions might be able to spot distinctive dark matter craters on its ancient surface. Physicists searching for ...

That would make it thousands of times more massive than any moon orbiting a solar system plane  — so massive it could make ...

A new discovery suggests the possibility of an exomoon with an unprecedentedly large mass, thousands of times larger than any ...