NASA’s robotic probe InSight detected and measured what scientists believe to be a “marsquake,” marking the first time a seismological tremor has been recorded on another planet, the Jet Propulsion Laboratory in California reported on Tuesday.
The breakthrough came nearly five months after InSight, the first spacecraft designed specifically to study the interior of a distant world, touched down on the surface of Mars to begin its two-year seismological mission on the red planet.
The faint rumble was roughly equal to a 2.5 magnitude earthquake, was recorded on April 6, the lander’s 128th Martian day, or sol.
It was detected by InSight’s French-built seismometer, an instrument sensitive enough to measure a seismic wave just one-half the radius of a hydrogen atom.
Scientists are still examining the data to conclusively determine the precise cause of the signal, but the trembling appeared to have originated from inside the planet, as opposed to being caused by forces above the surface, such as wind.
The size and duration of the marsquake also fit the profile of some of the thousands of moonquakes detected on the lunar surface between 1969 and 1977 by seismometers installed there by NASA’s Apollo missions.
The lunar and Martian surfaces are extremely quiet compared with Earth’s, which experiences constant low-level seismic noise from oceans and weather as well as quakes that occur along subterranean fault lines created by shifting tectonic plates in the planet’s crust.