What does “the dark side of the moon” mean to you? If you are of a certain age and uncertain taste, it evokes a 1973 album by Pink Floyd. If your memory is as pin-sharp as President Joe Biden’s is, you will also recall that in 1968, Americans were the first humans to see it, on the Apollo 8 mission. If you are Vladimir Putin, you will recall that it was the Soviet Union that pioneered our knowledge of it. You may also appreciate that one of your biggest fans in the West is Roger Waters of Pink Floyd, who really has gone over to the dark side.

The dark side isn’t actually dark. It is unknown. Its darkness is that of our own ignorance. A Soviet probe took the first photos of it in 1959. The Soviets published a two-volume Atlas of the Far Side of the Moon in 1960 and 1965, and we still use the Soviets’ nomenclature for its many craters. Despite the antagonisms of the Cold War, the Soviets named many of them after Westerners, including Joseph Priestley, H.G. Wells, Marie Curie, and Edward Jenner. Perhaps they thought they were winning.