Scientists say they’ve found potential new skylights leading to underground caverns on the Moon – the first to be seen at the poles, which could be important for future exploration.
The discovery was led by the SETI Institue and Mars Institute in California. Using images from NASA’s now-dead Lunar Reconnaissance Orbiter (LRO), they found the pits in a crater near the North Pole, which may be hiding underground ice.
“This discovery is exciting and timely as we prepare to return to the Moon with humans” Bill Diamond, president and CEO of the SETI Institute, said in a statement. “It also reminds us that our exploration of planetary worlds is not limited to their surface, and must extend into their mysterious interiors.”
Skylights like these on the Moon are holes in the surface that lead to underground tunnels, the remnants of ancient lava tubes in the lunar past. That lava is now long gone, but in its wake, the Moon’s interior is thought to be crisscrossed with tunnels and caverns.
These new pits were found on the Philolaus Crater, which is 550 kilometers (340 miles) away from the North Pole of the Moon. They’re located on the near side, which means they’re constantly looking towards Earth, as the Moon is tidally locked to our planet.
Previous research has suggested some of these may be large enough to house entire cities. As they are kept sheltered from cosmic radiation and the Sun, these tunnels are potentially desirable locations for future human explorers.
Most of our previous discoveries of skylights, of which there have been more than 300, have been found near the equator. So this latest discovery is all the more important, as the Moon’s poles are thought to be relatively rich in ice.
"All previous pits are located at lower latitudes," Dr Pascal Lee, a planetary scientist from the SETI Institute and Mars Institute who led the findings, told IFLScience.
"This distribution does not reflect a propensity for lava tube skylights to form at low latitude, but merely the fact that these features are much easier to identify at low latitude, where sunlight is able to illuminate the floors and vertical walls inside the pits."
At the moment it’s not certain that these pits seen are definitely lava tube skylights. However, their size, shape, and lighting conditions seemed to be consistent with other candidates seen so far.
Philolaus Crater is also interesting by itself as it’s thought to be relatively young, about 1.1 billion years old or so. This means it could give us a glimpse of the Moon’s more recent evolution.
“From the Philolaus skylights, Earth would loom just over the crater’s mountainous rim, near the horizon to the southeast,” Dr Lee said in a statement.
With the US recently announcing it's planning to return to the Moon, and Russia, China, and Europe also showing an interest, discoveries like this could be important for future human missions. Ice would not only be fascinating to study, but it’s also a useful resource for astronauts too.
(Update January 18: Note the validity of this discovery has been called into question)