Jinhai Zhang

The Moon is not just a rocky sphere, but a giant bell. Passing through it, gravitational waves cause it to vibrate almost imperceptibly. This tremor was predicted by Einstein, and Weber was the first to try to hear it with Earth-based detectors.

Gravitational waves are ripples in spacetime curvature that imperceptibly stretch and squeeze everything around. But the Moon, like a bell, catches these waves: as a gravitational wave passes through it, it makes our satellite vibrate.

In the northern part of Arabia Terra, there are fields that look like a giant brain: ridges and troughs wind like convolutions. On Earth, similar patterns form in cold regions when water in the soil freezes and thaws, causing stones to sort themselves into stripes. But the Martian ridges are taller — averaging 3.29 meters — while Earth's mechanisms produce less than half a meter.