A close-up of the Apollo 16 Moon ... like gems when light is shone through. Discover more about the gem that's as old as the solar system. At the entrance to this gallery you'll find a small slice of ...

Venus, Saturn, and Mercury are full of surprises this month, and they have one more awe-striking display in store. Before ...

A new image has emerged of the Red Planet rising above the lunar limb after being occulted by the moon in January.

The moon dims, the meteors fly, and the planets dance—these are the most exciting celestial events happening this month.