Earth has two moons, a group of scientists argues. One is that waxing and waning nightlight we all know and love. The other is a tiny asteroid, no bigger than a Smart Car, making huge doughnuts around Earth for a while before it zips off into the distance.
That's the scenario posited by the scientists in a paper published Dec. 20 in the planetary science journal Icarus. The researchers say there is a space rock at least 1 meter (3.3 feet) wide orbiting Earth at any given time. They're not always the same rock, but rather an ever-changing cast of "temporary moons."
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