Sweet surprise: if you look into Mars you can see that the crust of the Red Planet resembles a three-layer cake

Data beamed back to Earth by NASA’s InSight lander suggests that Mars’ crust is made up of three cake-like layers.

Anchored near the equator of Mars, the robot lander’s super-sensitive seismometer known as SEIS has recorded hundreds of ‘marsquakes’ over the past two years.

Each earthquake emits two sets of seismic waves, and by analyzing the differences in how those waves move, researchers were able to begin calculating the size and composition of the Earth’s crust, mantle, and core.

“We have enough data to answer some of these big questions,” Jet Propulsion Laboratory scientist Bruce Banerdt told Nature.

Launched in 2018, the InSight mission is the first time scientists have looked at a planet other than Earth.

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The Earth’s crust is divided into three bedrock layers: metamorphic, igneous, and sedimentary.

Scientists had structured the Mars crust theory in the same way, but had no data to work with so far.

According to the report in Nature, it is possible that Mars has only two layers, but a three-layer crust is consistent with the analysis of meteorites on Mars.

By comparing the marsquakes’ primary and secondary waves, they deduced that the crust is on average about 37 miles thick and nearly 42 at its thickest.

That’s significantly thicker than Earth, which has a crust that ranges from about 3 miles below the oceans to 18 miles below the continents.

InSight (short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) arrived on Mars in November 2018.

The probe, dubbed the ‘Mole’, was designed to burrow beneath the surface and take the planet’s temperature – but unexpected features in Mars soil made progress difficult.

Fortunately, other equipment on the lander is fully functional – including the seismometer, provided by the French space agency Center National d’Études Spatiales.

Since April 2019, SEIS has recorded more than 480 earthquakes. The vibrations are relatively mild, with no greater than a magnitude of 3.7.

“It’s a bit surprising we haven’t seen a bigger event,” said seismologist Mark Panning of NASA’s Jet Propulsion Laboratory.

Panning says it’s not clear yet if Mars is just more static than Earth or if InSight landed during a quiet interlude.

The earthquakes had been daily for some time, but ended abruptly in late June – right around the time the planet was entering its windiest season of the year.

The seismometer has shielding, but it is possible that the wind is strong enough to shake the ground and mask legitimate vibrations.

Researchers hope that more major earthquakes will follow, providing more insight into the inner layers of the planet.

“Sometimes you get big flashes of amazing information, but most of the time you tease what nature has to tell you,” Banerdt said.

“It’s more trying to follow a trail of tricky directions than having the answers presented to us in a nicely wrapped package.”