The Moon, long admired for its beauty and poetic charm, is quietly shrinking — and scientists say the process is creating fresh cracks and triggering moonquakes across its surface.
Researchers from the National Air and Space Museum’s Center for Earth and Planetary Studies have identified 1,114 newly documented surface features known as small mare ridges (SMRs). These add to a growing tally of tectonic structures caused by the Moon’s gradual internal cooling.
Why is the Moon shrinking?
Like a cooling apple that wrinkles as it loses heat, the Moon is contracting as its interior cools. This contraction forces the crust to compress, forming thrust faults called lobate scarps.
Earlier studies, including findings from the Apollo era, had documented such features mainly in the lunar highlands. However, the new study published in Science Advances shows similar structures widely distributed across lunar maria — vast basaltic plains formed by ancient volcanic activity.
Lead author Cole Nypaver noted that this is the first time scientists have confirmed the widespread presence of such features across both highlands and maria. In total, researchers have now catalogued 2,634 contraction-related cracks worldwide on the Moon.
Many of these features are relatively young in geological terms, averaging around 100 to 124 million years old — suggesting the Moon remains tectonically active.
What does it mean for future missions?
The ongoing contraction can trigger shallow moonquakes. While not felt on Earth, these tremors could pose risks to planned lunar bases.
Scientists say upcoming missions under NASA’s Artemis programme will gather more detailed seismic and surface data. Understanding lunar tectonics will be crucial for ensuring astronaut safety and infrastructure stability.
Although the Moon’s shrinking does not directly threaten Earth, it highlights that our nearest celestial neighbour remains a dynamic and evolving world.