Jupiter's moon just sent out a signal scientists can't fully explain—could this be our first real clue about alien life ...

Each Monday, I pick out North America’s celestial highlights for the week ahead (which also apply to mid-northern latitudes ...

Looking for a sky event this week? Check out our full Sky This Week column. September 7: Venus and Spica, side by side The ...

A frozen object beyond Jupiter is venting carbon dioxide gas into space, revealing what can drive activity so far from the ...

A Saturn encounter sent 450P onto a warmer orbit, where buried ice and carbon dioxide may now be awakening the tiny Centaur.