Huge Tubes Under the Moon’s Surface Could Hold Entire Cities

525388353 Photo: Henn Photography

Humans weren’t made to live on the moon. The high temperatures there can exceed 250 degrees; meteorites are a constant danger; the hazards of cosmic radiation loom large; and dust is an enormous nuisance. But living in the moon? Now, that could work.

The key is the existence of lunar lava tubes, which are large, hollow tunnels thought to have formed during long-ago volcanic eruptions. And a new theoretical study from a team at Purdue University is not only saying that they exist, but they’re large enough to hold entire cities. Like those on Earth, lunar lava tubes are thought to form when lava flows to the surface, allowing a layer to cool and insulate the still-molten lava below it. That lava keeps flowing and when it recedes, it leaves behind an empty tube.

Definitive proof of lunar lava tubes doesn’t exist. But theoretical work, along with images that appear to show openings to the tubes, makes a pretty strong case that they're real. The next logical question to ask is: Can these tubes make the moon more inhabitable? The team from Purdue, made up of members of the Department of Earth, Atmospheric and Planetary Sciences and a civil engineering professor, says yes.

Their calculations show that lunar lava tubes could be huge. Importantly, there also would be little risk of collapse. Lunar lava tubes, the study reveals, would be stable at diameters up to three miles across. "This wouldn't be possible on Earth, but gravity is much lower on the moon and lunar rock doesn't have to withstand the same weathering and erosion,” says graduate student David Blair, who led the study. “In theory, huge lava tubes — big enough to easily house a city — could be structurally sound on the moon.”

Living in lunar tubes would eliminate many of the problems associated with living on the moon’s surface. Temperature would be a manageable (if brisk) -20 C to -30 C, and the lava walls and roof would protect people and structures from taking a pummeling from airborne space junk. Still, this is just a theory. If we’re ever to know that lunar lava tubes truly exist, someone’s going to have to do some space spelunking.