© Haruyama et al./Geophysical Research LettersThis unusually deep feature on the moon (in box) is 65 meters wide and may be a portal into an underground cavern that once held flowing lava.
New revelations of a big hole in the moon don't revive the notion that our cosmic companion is made of Swiss cheese. Instead, scientists say, the unusually proportioned feature is most likely a portal into an underground cavern that once held flowing lava.
Analyses of high-resolution images taken by a moon-orbiting probe suggest that the 65-meter-wide, nearly circular feature is between 80 and 88 meters deep, says Carolyn H. van der Bogert, a planetary geologist at Westphalian Wilhelm's University Münster in Germany. Typical impact craters of this size, she notes, are less than 15 meters deep.
Although the hole is located in a lunar province once home to widespread volcanic activity, a dearth of hardened lava around the hole indicates that it isn't a volcanic crater, she and her colleagues report in the Nov. 16
Geophysical Research Letters. The geology of the region also suggests that the hole isn't associated with a fault zone.