An earthquake is caused when tectonic plates shift. But quakes themselves aren’t restricted to the earth. For example, small tremors have also been detected on the moon. They aren’t the handiwork of tectonic plates, however.

Instead, the moon is practically groaning from extreme temperature differences – from 121 degrees to –133 degrees Celsius, a breathtaking range of 250 degrees Celsius. The resulting strain leads to seismic activities called moonquakes.

They can also occur due to meteors striking the lunar surface. Indeed, the surface is pockmarked with thousands of craters – not surprising because the moon’s lack of an atmosphere allows even small impacts to be powerful enough to deform the ground.

A study published earlier this month unearthed yet another cause. Researchers found that the Apollo 17 lunar lander module, launched in 1972, may also have triggered some tremors. Scientists re-analysed the data collected by its instruments using artificial intelligence. They found that the lander itself set off very feeble seismic movements on the moon as it adjusted to the natural satellite’s drastic temperature changes.

As countries around the world – including India – plan to establish outposts on the lunar surface, studying moonquakes and their causes is crucial. If nothing else, it will help us build structures on the moon that don’t topple if a lander descends nearby.