This photo of the August 2012 blue moon was taken by Johan Clausen in Denmark. Johan Clausen Forty years ago today, Dec. 7, 1972, the astronauts of the Apollo 17 mission became the last people to launch into space and land on the Moon three days later.

Even though we haven't sent any astronauts to the Moon since Apollo 17, the Earth's only natural satellite is still revealing tons of new information.

NASA's recent mission to map the Moon's gravity field, for example, found hidden volcanoes on the Moon.

That's not the only recent Moon finding or interesting fact — here are some you may have missed.