The moon is whistling out of its last holes
Not enough that there is no life on the moon - the moon itself has long been considered dead. It is said that no lava has flowed over its surface for at least a billion years, which is why scientists have long regarded it as a cooled rock. New high-resolution images are now calling this supposedly certain knowledge into question. In at least one crater, the material was still in motion - "only" ten million years ago. We think we know relatives well. And the moon is always related to our earth. According to current models, the satellite formed in the early days of the planet, when a roving chunk the size of Mars collided with the fore-Earth, ripping a huge chunk out of it and eventually combining the orbiting debris into the smaller companion. A fierce play of gravitational and centrifugal forces followed, which kept the lunar rocks liquid for a while, but gradually abated as the moon retreated to a greater distance from the earth and only ever turned the same side to it in its coupled rotation. Then it cooled down inside. After all, it is said to be 3.2 billion years ago that the phase of widespread volcanic activity came to an end, and the last thin lava flows dried up around a billion years ago. So we're in the know.
Maybe not quite as good as we previously thought. A small structure called Ina looks surprisingly fresh to Brown University geoscientist Peter Schultz and his colleagues. So fresh that it hardly looks back on a billion years of slow decay. As a suspected volcanic crater with a diameter of only 2.8 kilometers and a depth of 60 meters, Ina really has no striking dimensions. On the other hand, there are numerous ramparts from 5 to 25 meters high or even less, plateaus of less than 10 meters and almost no signs of small meteorite impacts. If Ina were as old a volcanic crater as she should be, constant mini-collision with space stones in a kind of "sandpaper erosion" would have flattened all structures long ago and somewhat stronger chunks would have had to set new marks. But compared to the other structures of the moon, Ina's smooth complexion looks as if she looks back at most ten million years - according to previous thinking, much too young for beauty that is supposed to come from the cold interior.
But the spectroscopic investigation with the instruments of the space probe Clementine also brings Ina close to demonstrably young impact craters, which reveal a view of rock that has hardly aged. Both these craters and Ina's surface materials show large amounts of titanium-rich bas alt (mafite). The moon's normal envelope, on the other hand, consists of regolith rock more than forty feet thick.
So how does the fresh material in Ina come to the surface? The scientists rule out a real volcanic eruption in recent times. Otherwise the distribution would be different and, above all, more extensive. Instead, the weak rampart rings with the low elevations suggest a relatively low-energy process that "blows away" the otherwise overlying rock. That would point to gas ejection from the otherwise dormant volcano. And indeed, the Apollo missions had already found signs that the moon occasionally leaks some gas. Otherwise it would be difficult to explain the amount of radon found, which was also later detected.
So it looks as if the moon is in a way in the last puffs that it sheds over Ina. And not only here. At least four other structures are also suspected of possibly releasing carbon dioxide and even water vapor. They are all located in fragile places such as the intersections of lunar grooves. Apparently the moon is running out of air there. Which offers research the chance to take an indirect look at the internal chemistry of the satellite. That's good, since we have plans to visit relatives soon anyway.
