Dark Side of the Moon Mystery Solved After 55 Years
When looking up at the full moon at night, many of us see a "man in the moon" - a face smiling down at us from the lunar surface. The "face," of course, is just an illusion shaped by the dark splotches of lunar maria, which are the smooth plains formed from the lava of ancient volcanic eruptions. But very few dark splotches exist on far side of the moon. It is basically all mountains and craters. This mystery is called the "Lunar Far Side Highlands Problem" and dates back to 1959, when the Soviet spacecraft Luna 3 transmitted the first images of the dark side of the moon back to Earth. Researchers immediately noticed that fewer "seas" or maria existed on the portion of the moon that always faces away from Earth. Now, after 55 years of head-scratching, scientists have finally figured out why.
