Some very cool news out of Japan today where researchers say they have found an enormous lava tube stretching about 50 km (31 miles) under the lunar surface
The cavern, found in the Marius Hills area on the near side of the moon, is about 100 meters wide and extends for about 50 km, according to data taken by JAXA’s Selenological and Engineering Explorer (SELENE), also called the Kaguya moon probe.
In 2009, the Kaguya probe found a large shaft with an opening about 50 meters in diameter in the Marius Hills area. The shaft descends about 50 meters beneath the surface.
The JAXA team analyzed data obtained from a lunar radar sounder on the probe that indicated an underground structure extended west from the shaft.
The results were published in Geophysical Research Letters. You can find the abstract and a link to the paper here.