For the first time, the existence of a tunnel in the lunar subsoil has been demonstrated, which appears to be an empty lava tube. It is up to 80 meters long, located more than 100 meters below the surface, and can be accessed through a huge shaft near where Neil Armstrong and Buzz Aldrin left the first human footprints on the Moon. The international team of researchers that has reached this milestone in the knowledge of lunar geology publishes its study this week in the latest issue of the journal Nature Astronomy.
This discovery has an important impact on the plans of space agencies to establish colonies on the Moon, as the cave is large enough to house a human base underground, protecting astronauts from extreme temperatures and cosmic radiation. 'These caves have been theorized for more than 50 years, but this is the first time we have demonstrated their existence,' explains Lorenzo Bruzzone, professor at the University of Trento (Italy) and lead author of the research.
In 2010, as part of NASA's Lunar Reconnaissance Orbiter (LRO) mission, the miniature radio frequency instrument acquired data that included a 100-meter-wide hole in the Sea of Tranquility, the plain on which Apollo 11 landed in 1969. 'Years later, we have reanalyzed this data with complex signal processing techniques, which we have recently developed, and thus discovered radar reflections from the well zone; the best way to explain them is by the existence of an underground cave conduit,' says Bruzzone.
To confirm their explanation that the origin of these radar signals is an empty lava tube, the researchers visited the most similar volcanic caves known on the Canary island of Lanzarote and carried out radar simulations with a drone equipped with lidar technology to 3D scan underground cavities.
Data from lunar orbiters, such as the American Lunar Reconnaissance Orbiter and the Japanese Selene, have been used to locate more than 200 pits on the surface of the Moon, which were nicknamed skylights, and which scientists thought could be the entrance to large caves. But until now, none of those large caves had been found.
Bruzzone, Carrer, and their team decided to analyze the deepest known well on the Moon, which has an entrance approximately 100 meters in radius. According to their analysis, they estimate that to reach the empty lava conduit, it would be necessary to descend at least 130 to 170 meters. The tube could be up to 80 meters long and 45 meters wide, dimensions very similar to those of the minimum regulatory size for a soccer field.
The authors also consider that the accessibility and inclination of the conduit are promising for use as a lunar base. They emphasize that this type of cave could be very common under the lunar plains. The scientific importance of this work for the development of missions to the Moon lies in the fact that the surface of the Earth's natural satellite is a hostile environment for human life. Surface temperatures on the illuminated side of the Moon can reach 127°C, while temperatures on the non-illuminated side can drop to -173°C.
Cosmic and solar radiation can be up to 150 times more powerful on the lunar surface than on Earth, and there is a constant threat of meteorite impacts. These conditions drive the need to find safe sites for infrastructure construction that can support sustained exploration. Caves like this offer a solution to that problem.
Scientists have confirmed the existence of a cave on the Moon, not far from where Neil Armstrong and Buzz Aldrin landed 55 years ago, and suspect there are hundreds more that could house future astronauts. A team led by Italians reported this Monday that there is evidence of a considerable size cave that can be accessed from the deepest pit on the Moon. It is located in the Sea of Tranquility, just 250 miles (400 kilometers) from the landing site of the Apollo 11 spacecraft.
The pit, like the more than 200 discovered up there, was created by the collapse of a lava tube. The researchers analyzed radar measurements made by NASA's Lunar Reconnaissance Orbiter and compared the results to lava tubes on Earth. Their conclusions appeared in the journal Nature Astronomy.
According to scientists, the radar data only reveal the initial part of the underground cavity. They estimate it to be at least 130 feet (40 meters) wide and dozens of yards (meters) long, or probably more.
'Moon caves have been a mystery for more than 50 years. So it was exciting to finally be able to demonstrate the existence of one,' Leonardo Carrer and Lorenzo Bruzzone of the University of Trento wrote in an email.
Most of the pits appear to be located on the Moon's ancient lava plains, according to scientists. There could also be some at the Moon's south pole, the planned landing site for NASA astronauts later this decade. There are believed to be permanently shadowed craters there containing frozen water that could provide drinking water and rocket fuel.
During NASA's Apollo program, 12 astronauts landed on the Moon, starting with Armstrong and Aldrin on July 20, 1969. The findings suggest there could be hundreds of pits on the Moon and thousands of lava tubes. These places could serve as a natural refuge for astronauts, protecting them from cosmic rays and solar radiation, as well as micrometeorite impacts. Building habitats from scratch would take longer and be more challenging, even considering the possible need to reinforce cave walls to prevent collapse, according to the team.
The rocks and other materials inside these caves, unaltered by the harsh surface conditions over the centuries, may also help scientists better understand the evolution of the Moon, especially as it relates to its volcanic activity.
- The discovery of a lunar cave has significant implications for future lunar exploration and colonization. The ability to establish a human base underground would provide much-needed protection from the Moon's extreme temperatures and high levels of cosmic and solar radiation. This discovery could accelerate plans by space agencies to create sustainable infrastructure on the Moon.
- The research conducted by the team from the University of Trento involved reanalyzing data from NASA's Lunar Reconnaissance Orbiter using advanced signal processing techniques. This led to the identification of radar reflections indicative of an underground cave conduit. To validate their findings, the researchers conducted radar simulations in volcanic caves on Earth, specifically on the Canary island of Lanzarote.
- The study highlights the importance of locating safe sites for infrastructure on the Moon, given the hostile conditions on its surface. The existence of such caves offers a potential solution, providing natural protection from the harsh environment. The findings also suggest that there could be many more similar caves on the Moon, which could be crucial for the success of long-term lunar missions.
- The potential for these caves to serve as natural refuges for astronauts is particularly promising. They could offer protection from cosmic rays, solar radiation, and micrometeorite impacts, which are significant hazards on the Moon. Additionally, the materials inside these caves, which have remained unaltered for centuries, could provide valuable insights into the Moon's volcanic history and evolution.
