A team of researchers think they’ve discovered a cave on the Moon in radar images of the lunar surface, which they posit could be a future site for an established human presence on our rocky satellite.
Where is this tunnel? How big is it?
The tunnel is in the Mare Tranquillitatis (Sea of Tranquility) pit, the deepest known pit on the Moon. (If the name is familiar to you, the Sea of Tranquility is where the Apollo 11 mission landed in 1969.)
The pit formed due to a lava tube’s roof collapse or a collapse of a void structure created by tectonic processes. To look for potential cave structures within the pit, the researchers studied side-looking radar images taken by the Lunar Reconnaissance Orbiter’s Mini-RF instrument between 2009 and 2011. The team then conducted 3D radar simulations of potential geometries of the pit and its cave, to determine that the brightness they saw in radar images could be due to subsurface features.
Ultimately, the team determined there is a tunnel in the pit that is between 98 feet (30 meters) long and 262ft (80m) long. The tunnel is roughly 148ft (45m) wide and is either flat or inclined with a maximum steepness of 45 degrees. Their research was published today in Nature Astronomy.
A cave on the Moon could be a boon for lunar exploration
“The exploration of lunar caves through future robotic missions could provide a fresh perspective on the lunar subsurface and yield new insights into the evolution of lunar volcanism,” the team wrote in the paper. “Furthermore, direct exploration could confirm the presence of stable subsurface environments shielded from radiation and with optimal temperature conditions for future human utilization.”
As previously reported by Gizmodo, the shadowy overhangs of lunar pits keep parts of them relatively temperate. In 2022, data from the LRO suggested the interior of some pits on the moon hovered around 63° Fahrenheit (17.2° Celsius).
Study co-authors Leonardo Carrer and Lorenzo Bruzzone, both researchers at Italy’s University of Trento, told Gizmodo that building a lunar base in a cave has “significant advantages” compared to such a structure on the surface, including:
- Protection from cosmic rays and solar radiation, which are harmful to human beings and constantly hit the lunar surface.
- Thermal stability, as temperatures on the lunar surface vary dramatically whereas the interior of lunar caves maintain a stable temperature.
- Micrometeorite protection, as the cave rocks provide a natural shield against impacts.
- Resource availability, as caves might be closer to a source of water ice or other minerals.
What’s next for understanding the lunar interior?
A semi-permanent presence on the Moon would be a boon for research missions on the satellite’s surface as well as a launchpad for missions farther out in the solar system.
Besides the caves’ setting for potential lunar bases, Carrer and Bruzzone said that lunar history could be preserved in such caves. Unaltered by the harsh environment on the lunar surface, the rocks in lunar caves “can provide significant insights” into questions about the Moon’s volcanic activity and the composition of the satellite’s interior.
Without an orbiter with more up-to-date radar instruments, the new research is basically a teaser trailer for the type of science that could be done in such lunar recesses. Nevertheless, the finding is exciting, both for a better understanding of the history of the Moon and (potentially) establishing humankind’s presence on it.
