Quakes on Mars Serve Up New Details About the Red Planet's Core

pcmag.com:

Seismic waves detected in 2021 by NASA's InSight Mars lander have led researchers to a landmark discovery. Data from these temblors—the first direct observations(Opens in a new window) of another planet's core—suggest Mars' liquid iron center is smaller and more dense than previously thought.

Originating on the opposite side of the planet from NASA's lander, the so-called "farside quakes" highlighted a crucial point: The further the tremor from InSight, the deeper the seismic waves travel before being detected.

"We've made the very first observations of seismic waves traveling through the core of Mars," lead study author Jessica Irving, of the UK's University of Bristol, said in a statement(Opens in a new window). "We've effectively been listening for energy traveling through the heart of another planet, and now we've heard it."

As it turns out, Mars' core is more than just a ball of iron; it also contains a large amount of sulfur, according to Irving, as well as other elements, including a small amount of hydrogen.

"We needed both luck and skill to find, and then use, these quakes," Irving said. "Farside quakes are intrinsically harder to detect because a great deal of energy is lost or diverted away as seismic waves travel through the planet."

Unlike our home, Mars has no tectonic plates, so most shocks are caused by faults, or rock fractures, forming in the planet's crust due to heat and stress. Or, as was the case with one of the two quakes in question, a meteoroid impact.

"These two farside quakes were among the larger ones heard by InSight," according to Bruce Banerdt, InSight's principal investigator at NASA's Jet Propulsion Laboratory. "If they hadn't been so big, we couldn't have detected them."

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