Rima Ariadaeus photographed from Apollo 10. The crater south of the channel is known as Silberschlag.

(NASA)

Beneath the moon’s surface, empty tubes once filled with lava during an age when the moon actively shot fire into space have been found, scientists suggest.

Teams have searched to obtain more information on these buried tubes, which are thought to be large and sturdy enough to hold entire cities, according to a Purdue University study.

“Humans have been living in caves since the beginning, and it might make senseonthe Moon, too," David Blair, a graduate student in the University'sDepartment of Earth, Atmospheric and Planetary Sciences, told Universe Today.

"We found that if lunar lava tubes existed with a strong arched shape like those on Earth, they would be stable at sizes up to 5,000 meters, or several miles wide, on the moon," said Blair. "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.”

The purposed size of a lunar lava tube in comparison to the city of Philadelphia.

(Purdue University/David Blair)

These tubes would make an ideal location for a moon base, using their thick roofs to protect explorers from harmful radiation and minor meteorite impacts, says a study from the Lunar and Planetary Institute.

Prior to new information showing signatures of at least ten possible buried tubes, the only hints pointing to the tubes’ existence were slight surface features, like skylights and channel-like depressions where tubes may have collapsed.

It’s “the strongest evidence yet that shows signals consistent with that of buried, empty lava tubes on the moon,” Purdue’s Rohan Sood announced at the Lunar and Planetary Science Conference.

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Sood’s team used data from NASA’s pair of GRAIL spacecraft, which flew above the moon’s surface to map its gravitational field. The moon’s gravitational field differs with masses below the surface.

“If you fly over a lava tube, there’s going to be a dip in gravity,” Sood explained.

The team spotted at least 10 gradational anomalies in the GRAIL data that could lead to lava tubes beneath the surface.

While the GRAIL data can’t confirm the presence of the actual tubes, it’s led Sood and his colleagues to propose LAROSS, a robot that would be able to look beneath the surface using ground-penetrating radar.

“The proposed radar will not only help confirm our findings but will also give us an opportunity to find smaller lava tubes, ones that were beyond the resolution of GRAIL gravity data,” says Sood.

“People have studied and talked about all of these things before, but our work shows that those kinds of opportunities could potentially exist – now we just have to find them,” Blair said.

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