New satellite photos have revealed what scientists have long suspected: There are large tunnels made from lava running beneath the Moon's surface. These caves could provide shelter from radiation for future lunar settlers. Or they might already be occupied!
Observers of the Moon's surface have seen "sinuous rilles," or long, winding depressions on its surface that suggest the presence of underground tunnels. Such tunnels would be formed when lava rips through an underground area, then drains away, leaving a long tube behind. (Such structures exist on Earth, too.) At last, a satellite captured solid evidence for these tunnels when it snapped this picture of a massive hole in the Moon's surface.
The hole is actually what's called a "skylight," or a rift in the top of an ancient lava tunnel. According to New Scientist:
The team found the first candidate skylight in a volcanic area on the moon's near side called Marius Hills. "This is the first time that anybody's actually identified a skylight in a possible lava tube" on the moon, [researcher Carolyn] van der Bogert, who helped analyse the feature, told New Scientist.
The hole measures 65 metres across, and based on images taken at a variety of sun angles, the the hole is thought to extend down at least 80 metres. It sits in the middle of a rille, suggesting the hole leads into a lava tube as wide as 370 metres across.
It is not clear exactly how the hole formed. A meteorite impact, moonquakes, or pressure created by gravitational tugs from the Earth could be to blame. Alternatively, part of the lava tube's ceiling could have been pulled off as lava in the tube drained away billions of years ago.
We may not be able to explore this tube any time soon, however. Like lava tubes on Earth, it's possible that this tunnel is filled with debris and would require excavation to unblock.
What's important, however, is that we now have solid evidence that lava tubes exist beneath the Moon's surface, which means Moon real estate just got a little more appealing. Unless, of course, Moon natives already live there.
via New Scientist