Scientists have long hypothesized that the moon was once geologically active, but evidence about this hypothesis has been elusive. However, a recent observation may finally prove this: a possible lava tubes has been recently spotted.
As reported by the National Geographic, latest evidence based on a survey of moon's gravitational fields shows some tell-tale signatures of possible lunar lava tubes. These ancient sub-lunar lava tubes are large and sturdy enough to contain entire cities, making them ideal as locations for future moon bases.
Lunar lava tubes have thick roofs that provide natural protection against radiation and meteor impacts. Speculative evidence for their existence was previously based on visible features such as channel-like depressions and skylights and rilles.
The latest findings were presented by Rohan Sood from Purdue University during the 47th Lunar and Planetary Science Conference. According to his report, the strongest evidence came from signature signals from a lunar mapping survey.
Scientists who conducted the study began their search for lunar lava tubes in the region known as the Marius Hills. Their first clue was the suspected skylight that opened into one of the hidden lava tunnels.
The area has been a likely candidate for the location of the tubes when a possible skylight opening was discovered by the Japanese satellite Kaguya, which was sent to orbit the moon in 2009.
The opening had a width of approximately 65 meters and depth of 80 meters.
Two rilles were also observed, suggesting ancient lava flows near the portal. Direct visual observation of the tube is currently not practical, prompting scientists to use gravity mapping data in making their assessments.
Lava tubes are hollow and could produce dips in gravitational measurements. These dips have specific signatures that can be assessed.
Decades before the gravitational fields of the moon were mapped, the Marius Hills region has already been identified as a possible area where lava tubes could be found. According to an earlier study, the region has features resembling volcanic origins, such as irregular shaped craters.