NASA’s InSight lander, which has been sitting on the surface of Mars since November, just detected its first possible quake on the Red Planet. It’s a big first in the spacecraft’s ongoing mission to listen for rumblings coming from inside the planet. Unfortunately, the so-called “marsquake” was too small to help scientists learn more about Mars’ structure. But the event proves that Mars is seismically active and that InSight might be able to pick up more quakes in the future.
Launched in May 2018, the InSight lander has a relatively simple goal: sit still on Mars and listen for these marsquakes. To do this, the spacecraft is equipped with an incredibly sensitive, dome-shaped seismometer built by France’s space agency, CNES. The instrument is so sensitive, in fact, that it must be sealed in a vacuum so that it can pick up the tiniest perturbations in the Martian crust. InSight delicately placed the seismometer, nicknamed SEIS, onto the surface of Mars on December 19th, and the spacecraft has been trying to pick up a quake since.
That first signal came on April 6th, proving that Mars is at least capable of quaking
That first signal came on April 6th, which proved that Mars is at least capable of quaking. The InSight team is pretty sure the quake came from within Mars itself and wasn’t caused by wind or some other external force shaking the instrument. So far, InSight has picked up three other signals of seismic activity, but all were much weaker than the April 6th event. The cause of the quake is still unknown, but picking it up is still a big validation for the team that built the seismometer. “We’ve been waiting months for our first marsquake,” Philippe Lognonné, the principal investigator for SEIS, said in a statement. “It’s so exciting to finally have proof that Mars is still seismically active. We’re looking forward to sharing detailed results once we’ve studied it more and modeled our data.”
Scientists believe that the origins of marsquakes are a bit different than the origins of seismic activity here on Earth. Many of our planet’s earthquakes are the result of plate tectonics. Huge portions of the Earth’s crust (called plates) are constantly shifting and rubbing against one another, and this movement is driven in part by heat deep inside the Earth. On Mars, which is cooler and less active, quakes are thought to be caused by smaller movements along cracks within the planet’s rocky crust. As the planet cools over time, its rocks shrink and release energy, possibly resulting in some shaking. This is probably the same mechanism that causes quakes on the Moon — events that NASA’s Apollo astronauts picked up when they traveled to the lunar surface in the 1960s and ‘70s.
Ultimately, the mission team behind InSight hopes to use the spacecraft’s marsquake detections to figure out what Mars is made of. The waves from a quake pass through all of the different rocks and material within the planet, so these signals provide crucial information about the structure of the Martian interior. It’s like taking an ultrasound of the planet.
“this first event officially kicks off a new field: Martian seismology.”
While the quake on April 6th was too small to help scientists achieve this goal, there is still hope that NASA will have much more data to work with soon. “We’ve been collecting background noise up until now, but this first event officially kicks off a new field: Martian seismology,” Bruce Banerdt, InSight’s principal investigator at NASA’s Jet Propulsion Laboratory, said in a statement.
In the meantime, the InSight lander is still having trouble with its other big instrument. The spacecraft also came to Mars equipped with a self-hammering drill that’s designed to burrow into the planet’s surface in order to take the world’s internal temperature. Unfortunately, InSight’s drill, nicknamed the “mole,” got stuck while hammering itself into the ground on February 28th. It’s possible that the mole hit some kind of dense rock during the drilling process, and scientists have been troubleshooting ways to free the instrument so it can dig deeper into the planet. The mole hasn’t budged.
While one of InSight’s instruments has struggled, the other one is just now kicking off its mission. NASA will hopefully come up with a solution for the mole soon, allowing both of the spacecraft’s major tools to learn as much as possible about the Red Planet.