Scientists thought they had a pretty good idea about the history of volcanic activity on the moon. It was believed to have wrapped up in the long-distant past, about 1 billion to 1.5 billion years ago, and it had left behind undeniable marks on the lunar surface. Recent research has even traced the rather than impact craters.
What's new now is that scientists have spotted evidence that volcanic activity may have continued for much, much longer than previously thought.
NASA's Lunar Reconnaissance Orbiter has its space eyes on some intriguing rock deposits on the moon. We can't see these from Earth, but the LRO has a front-row seat. The space agency describes the deposits as being "characterized by a mixture of smooth, rounded, shallow mounds next to patches of rough, blocky terrain." Researchers call them "irregular mare patches," and so far have cataloged 70 of these patches, which average less than a third of a mile across at their widest points.
Scientists have made a strong case for the irregular patches' origin coming from small basaltic eruptions. A study on the subject was published over the weekend in Nature Geoscience. Researchers believe at least a few of these patches are less than 100 million years old. One particularly well-studied patch, named Ina, could be a young whippersnapper, coming in at less than 50 million years old. This would mean the moon was still sporting volcanic activity back when Earth was home to dinosaurs.
"This finding is the kind of science that is literally going to make geologists rewrite the textbooks about the moon," says John Keller, LRO project scientist.
If the research is confirmed, then scientists will have their hands full with rethinking other moon-related subjects, such as what's currently known about the interior temperature of the moon. "The existence and age of the irregular mare patches tell us that the lunar mantle had to remain hot enough to provide magma for the small-volume eruptions that created these unusual young features," says Sarah Braden, lead author of the study.
We could be peeking into a previously unknown chapter of the moon's history. At least one moon researcher is rooting for some hands-on expeditions in order to delve deeper into the mysterious patches. "These young volcanic features are prime targets for future exploration, both robotic and human," says Mark Robinson, LROC principal investigator at Arizona State University.
Perhaps it's time for another manned moon mission.