Another mystery around the moon has finally been solved

Vaughn Highfield June 8, 2018

The moon still holds many mysteries. For instance, we still don’t really know what’s on the dark side of the moon, and it’s only recently we realised the moon is causing us to have longer days on Earth. The latest mystery to be resolved, however, dates back to the early moon landings of the 1970s.

When astronauts on the Apollo 15 and Apollo 17 missions arrived on the lunar surface it was a warmer place than they were expecting. Part of their mission was to drill probes into the volcanic soil to understand how heat escapes from the moon’s now dead core. But if the core is dead, how is the surface of the moon still radiating a level of heat higher than initially expected?

According to AGU, The probes began recording temperatures over time but, due to fluctuations in sunlight and the residual heat from drilling, it would take a while until any truly useful information could come to pass. Long-term readings, courtesy of the Lunar and Planetary Institute, suggest that the moon’s surface temperature fluctuates to around 18 to 24% of Earth’s own.

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So far, so ordinary. However, the lunar probes actually registered heat increases around the landing sites of the Apollo missions long after the original measurements were being taken. The idea of an internal heating process from the moon’s core was already ruled out, so what was causing this increase in temperature?

Thanks to some wonderful sleuths at Texas Tech University, we may finally know the answer, and it’s down to us humans. Hundreds of data tapes recorded the incidents around rising temperatures from the probes, but after the experiments ended in 1977 many were lost – with only 1971 to ‘74 remaining archived.

Having painstakingly restored the tapes since the Texas Tech team began their restoration project in 2010, it was uncovered that the heat recording from the probes actually came from the surface. Temperature increases were first detected by surface-level probes before registering on deeper-level ones. By cross-referencing data timestamps with images of the lunar surface at the time, the team cracked the mystery.

Writing in the Journal of Geophysical Research: Planets, the team explained that it was due to human intervention that the moon began to heat up. “Images of the Lunar Reconnaissance Orbiter Camera over the two landing sites show that the regolith on the paths of the astronauts turned darker”, thus lowering its reflectivity and allowing for the absorption of more heat.

“We suggest that, as a result of the astronauts’ activities, solar heat intake by the regolith increased slightly on average, and that resulted in the observed warming.”

It looks like, no matter where mankind goes, we’re always able to ruin the environment very quickly. This bodes well for human settlers on Mars…