Just last week, scientists discovered that the moon's unique features that make up the "man in the moon" were probably caused by volcanic activity, and not by asteroids, as previously thought. However, now, new data suggests that this volcanic activity happened much more recently than scientists thought.
After scientists realized that the moon once had volcanoes, they concluded that the volcanic activity stopped quickly, about a billion years ago. However, data from NASA's Lunar Reconnaissance Orbiter (LRO) is showing a different story.
The LRO observed rocks and textures on the moon's surface that are less than 100 million years old. In Earth time, that's when dinosaurs reigned supreme. Some of those rocks, though, were even less than 50 million years old.
Features, such as the "man in the moon" are part of the moon's volcanic plains. In images, part of these features are like smooth mounds, about .3 miles across, so small that even telescopes on Earth can't see them. These mounds generally sit next to rougher "blocky" terrain, in the form of craters.
Apollo 15 astronauts first spotted one of these areas, called Ina, in 1971. However, astronomers believed that Ina was an anomaly, something that only occurred in that one area on the moon's surface.
However, the LRO's camera recently changed that perspective. Astronomers from Arizona and Germany looked over images from the orbiter and discovered 70 of these features scattered across the face of the moon.
This suggests that volcanic activity wasn't limited to just one area, but happened all over the moon's surface. Because there are so many of these areas with these distinct large features, scientists estimated their age at about 50 to 100 million years old.
This changes what we know about the temperature of the moon's interior. For that much magma, the moon's mantle would have been very hot. But with the activity being more recent, this means that the moon's mantle is still hot, at least hotter than we currently think.
This, coupled with data about lunar volcanoes, changes almost everything we know about the moon.
"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.
Confirming LRO's data, though, involves more research and another lunar mission.
"These young volcanic features are prime targets for future exploration, both robotic and human," says Mark Robinson, LROC principal investigator.