Is this going to throw off the tides and send Earth into disarray? Probably not. But the moon does appear to be shrinking. According to a new sudy, the surface of the moon is displaying some relatively young geological features—they are only about a billion years old—that are usually indicative of a planetary body’s cooling and contracting. Known as lobate scarps, the features were photographed by the Apollo 15, 16, and 17 missions. "As the interior cools, it contracts, and the crust of the moon has to adjust to the reduced volume," said the study’s lead author. "That causes this breaking of the crust into these small faults." Overall, the moon’s diameter seems to have shrunk by about 600 feet since its formation, though the contraction only began recently.