In an article published in Geophysical Research Letters, Japanese explorer Junichi Haruyama says that the Japanese Kaguya orbiter has discovered at least one crater on the lunar surface, possibly an extinct volcano
The crater is almost 65 meters in diameter and is located in the volcanic region of Marius Hills, on the side of the moon that faces the Earth. Japanese scientists say that the crater emerging on the lunar surface is a "pipe" through which hot lava used to come to the surface. Astronomers were immediately attracted to this crater, as it was different from many others.
“Of course, there are many possible variants of the origin of the hole on the lunar surface. The most obvious is the impact of a meteorite, despite the fact that the moon is often bombed by meteorites. However, this is an untenable version. Kaguya observed the crater nine times from different angles, in different light conditions, including when the Sun shone on the crater almost perfectly. Our calculations showed that the crater is at least 88 meters deep. A meteorite is not capable of creating such a hole,”says Haruyama.
Another option that came to mind of scientists is the mouth of a volcano. However, no traces of eruptions, in particular lava flows or volcanic dust, have yet been found near the crater. Today the vent is in an isolated position. Japanese scientists believe the reason for this anomaly is this: due to the very deep vent, volcanic eruptions could simply not reach the surface. Another option suggests that lava is hidden from observation by a layer of lunar soil.
Japanese experts suggest that if there really was lava, then look for its traces within a radius of 370 meters from the crater. In the publication, scientists note that if lava is still found, and in the future it can be studied, then people will have unique data on the internal structure of the moon.