Because we’ve been sitting on the same rock for thousands of years, sometimes our language can tend to be a little Earth-centric. The word earthquake, for example, feels universal, as if it can be applied to any shaking ground. But zoom out beyond our tectonic plates, and the vocabulary shifts.
Mars, for instance, has marsquakes.
They sound too silly to be real, as if a Netflix show about future Mars settlements made up a scary natural disaster. But tremors on Mars are a thing, and right now scientists believe they have detected a quake on Mars for the first time.
Scientists know this because they sent a seismometer to our planetary neighbor. The instrument arrived last year, on board a NASA lander called InSight. The seismometer, small and dome-shaped, has sat on the brick-colored surface since, waiting for hints of movement below the surface. On April 6, it caught something, a “quiet but distinct” signal, scientists said. A rumble from the depths.
“We’ve been waiting months for our first marsquake,” Philippe Lognonné, a geophysicist at the Institute of Earth Physics of Paris who leads the seismometer team, said in a statement this week.
Scientists have suspected for decades that they’d find this phenomenon if they had the right tools to look. Unlike Earth, Mars lacks tectonic plates that glide over its mantle, jostling the ground when they touch. But like Earth, Mars has three distinct layers—a rocky crust, a mantle, and a metal core—and it’s still cooling from its fiery formation out of a primordial cloud of cosmic dust. Even now, billions of years later, heat radiates from its center and can be strong enough to crack the surface and escape. The fracturing sends seismic waves streaming in all directions.