The surface of the Moon is certainly not hospitable. Temperatures can reach extremes of 127 degrees Celsius on the illuminated side, and lows of -173 on the shadow side. And the lack of an atmosphere means that cosmic and solar radiation strike with a force that can be up to 150 times greater than what we experience on Earth. For this reason, establishing a permanent human presence on the satellite, as envisaged by NASA’s plans, will not be easy: a location is needed that will protect astronauts from temperatures, radiation and the impact of meteorites. A new international study led by the University of Trento could have the solution: enormous caves that dot the surface of the Moon, whose existence researchers have managed to demonstrate for the first time in the pages of Nature Astronomy.
Research
The existence of these lunar tunnels has been theorized for decades. They are lunar lava tubes, structures formed during ancient eruptions dating back to the period in which the Moon was still geologically active, which collapsed in the following millions of years to form enormous underground caverns reachable from the surface. They would be the perfect place to build a station on the surface capable of providing shade and protection for astronauts, but until now there was no definitive confirmation of their existence.
To obtain it, the international team led by the University of Trento used data obtained by NASA’s Lunar Reconnaissance Orbiter (Lro), and in particular radar images captured by the Mini-Rf (Miniature Radio-Frequency) instrument of a “well” located in the Sea of Tranquility, a large basaltic plain on the visible side of our satellite. Studying the data relating to this cavity – the deepest known on the Moon – the researchers noticed something strange: an increase in radar brightness on the western side of the well, a strong indication of the presence of a lava tube.
To be more certain, the researchers then resorted to a simulation, and by feeding the algorithm data collected by the radar they obtained a 3D model that, consistent with the observations, suggests the existence of a conduit that expands underground from the western side of the well.
The simulation
“Thanks to data analysis, we were able to model a portion of the conduit,” explains Leonardo Carrer, a researcher at the University of Trento and the study’s first author. “The most likely explanation for our observations is that it is a hollow lava tube.” The researchers estimate that the conduit is located at a depth of about 130-170 meters, that it is 30 to 80 meters long and about 45 meters wide. The results also suggest that it is slightly inclined, with a slope of up to 45 degrees. Perfect conditions – the researchers estimate – to host a future lunar base.