First direct evidence of underground lava tube on Moon’s surface found

For more than 50 years, scientists have speculated about hidden lava caves on the Moon.

Thanks to an international team led by the University of Trento, Italy, scientists have the first-ever confirmation of a lava tube in the lunar subsurface.

Lava tubes are a fascinating volcanic feature. These underground tunnels are produced by lava that formerly flowed across the Moon’s surface. The outer layer cooled and formed first, functioning as a shell. Meanwhile, the molten rock within continued to flow before draining away. This procedure left a hollow, extended chamber under the surface.

“We have proved with measurements the existence of a tunnel and we have identified the gateway to the entrance of the tunnel,” Lorenzo Bruzzone, professor at the University of Trento, told Interesting Engineering (IE).

Use of orbiter data

This exciting discovery wasn’t made by digging. Instead, researchers reanalyzed data from NASA’s Lunar Reconnaissance Orbiter (LRO) mission, which first spotted the lunar pits or lava tubes in 2009.

Using special techniques, they found radar reflections that point to a giant underground tunnel in a lunar area called Mare Tranquilitatis.

“In 2010, as part of the ongoing LRO NASA mission, the Miniature Radio-Frequency (Mini-RF) instrument acquired data that included a pit in Mare Tranquilitatis. Years later we have reanalysed these data with complex signal processing techniques we have recently developed, and have discovered radar reflections from the area of the pit that are best explained by an underground cave conduit,” explained Bruzzone in the press release.

The data provided compelling evidence for the existence of an empty lava tube. Scientists used this data to create a model of a section of the tunnel, which perfectly aligns with their observations.

Lava tubes may host Moon base

The Moon is a land of extremes and supports a harsh environment. Brutal temperatures and constant radiation pose a huge challenge for future lunar explorers.

Temperatures on the sun-baked side soar to 260.6°F (127°C) , while the unlit side is a cold wasteland with temperatures as low as -279°F (-173°C).

However, there are other risks beyond temperature fluctuations. The Moon is constantly bombarded by sun radiation and deep space radiation, at levels 150 times stronger than Earth.

The Moon’s deep pits might connect to vast tunnels, offering potential shelters for future lunar colonists.

These natural shelters may safeguard future human explorers from cosmic rays, solar radiation, and micrometeoroid impacts. And could be ideal locations for building safe and sustainable lunar bases.

“In the future, it will be possible to define a robotic mission that can enter the cave through the pit and explore with different instruments the interior of the cave. This will allow us to discover a completely new world in the subsurface of our natural satellite,” explained Bruzzone to IE.

“On the other hand, there are potential risks on the use of caves to be considered and analyzed,” Bruzzone added. These include ensuring the stability of the cave for human settlement.

Moreover, the author highlights that the analysis of rocks inside these caves could lead to discoveries related to the lunar evolution.

Interestingly, the study highlights the importance of re-examining existing data for a better understanding of the mysterious lunar terrain for future crewed lunar exploration efforts.

The research, funded partly by the Italian Space Agency, also included researchers from the University of Padua and La Venta Geographic Explorations APS.

The findings were published in the journal Nature Astronomy.