NASA's InSight lander, which touched down on Mars in November after a seven-month journey, sensed the seismic signal on April 6, the space agency said Tuesday.
Mission scientists are still working to confirm the source of the faint trembling, though it appears to have come not from the wind or movement of the lander's robotic arm but from below the Martian surface. If confirmed, it would be the first seismic activity ever detected on Mars.
"We've been collecting background noise up until now, but this first event officially kicks off a new field: Martian seismology!" Bruce Banerdt, a geologist at NASA's Jet Propulsion Laboratory in Pasadena, California, and the principal investigator of the InSight mission, said in a statement.
The 800-pound lander is parked on the Elysium Planitia, a broad, mostly rock-free plain just north of the Martian equator. The lander is designed to operate on the surface of Mars for two years, learning about the Martian interior as a way to boost our understanding of the formation of Mars and other rocky worlds, including Mercury, Venus, Earth and the moon.
The detection of the marsquake shows that the lander's Seismic Experiment for Interior Structure (SEIS) seismometer is working, though the tremor was too small to reveal anything about the Martian interior. But mission scientists expect the lander to detect more — and bigger — quakes.
"We expect to get one quake larger by a factor 10 approximately every 5-10 quakes," Philippe Lognonné, a professor of geophysics and planetary science at the University of Paris Diderot and the leader of the seismometer team, said in an email. "These larger quakes will be those enabling us to make the full science we want to make on the internal structure, and which will tell us the crust thickness and core size. Not this one."
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