Nice surprise: the first look of NASA’s Insight spacecraft inside Mars reveals that the crust of the Red Planet looks like a three-layer cake
- The seismograph has recorded more than 480 earthquakes since April 2019
- Differences in how seismic waves move allow scientists to assess the crust size and composition
- They believe that the crust of Mars is about 23 miles thick, which is much thicker than the Earth’s crust
- Seismic activity has virtually stopped, with only four earthquakes since June
Data sent back to Earth from NASA’s InSight Lander indicates that the Martian crust consists of three layers, like a cake.
Installed near Mars’ equator, the super-sensitive seismometer, known as SEIS, has recorded hundreds of « swamps » in the past two years.
Every earthquake emits two sets of seismic waves, and analyzing the differences in how these waves move allowed researchers to begin calculating the size and composition of the planet’s crust, mantle and core.
« We have enough data to start answering some of these big questions, » said Bruce Banerdt, JPL scientist. nature.
The InSight mission launched in 2018, the first time scientists looked inside a planet other than Earth.
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Analysis of primary and secondary waves from hundreds of earthquakes indicates that the crust of the Red Planet consists of three cake-like layers
The Earth’s crust is divided into three rock sub-layers: metamorphic, igneous and sedimentary.
Scientists had assumed that the crust of Mars was similarly organized, but until now, they had no data to work with.
According to the report in Nature, it is possible that Mars only has two layers, but a three-layer crust matches the analysis of Martian meteorites.
By comparing the primary and secondary waves of swamps, they concluded that the thickness of the crust is about 23 miles on average, and approaching 42 at its maximum thickness.
NASA’s Insight lander arrived at Mars in 2018, but its Mull probe had difficulty drilling beneath the surface.
InSight’s ultra-sensitive seismometer, known as SEIS, recorded more than 480 earthquakes. When analyzing primary and secondary waves from these earthquakes, researchers believe that the crust of Mars is about 23 miles thick.
This is much thicker than land, as the Earth’s crust varies from about 3 miles under the oceans to 18 miles under the continents.
InSight (short for inner exploration using seismic investigations, geodesy, and thermal transfer) arrived on Mars in November 2018.
Its probe, called Mole, is designed to drill below the surface and measure the temperature of the planet – but unexpected properties in Martian soil have made progress difficult.
Other equipment on the probe is fully functional, thankfully – including a seismometer, provided by France’s space agency, the National Center for Space Studies.
Since April 2019, SEIS has recorded more than 480 earthquakes. Tremors are relatively mild, and are no more than 3.7 degrees.
« It’s a bit surprising that we haven’t seen a bigger event, » said seismologist Mark Banning of NASA’s Jet Propulsion Laboratory.
Banning says it’s not yet clear if Mars is more stable than Earth or if Insight has descended during a quiet interval.
Earthquakes have been daily for some time, but came to a sudden halt in late June – around the same time as the planet entered its windiest season of the year.
The seismograph has a shield, but the winds could be so strong that they shake the ground and mask legitimate tremors.
Researchers hope that more large earthquakes will follow, giving deeper insight into the planet’s inner layers.
« Sometimes you get big flashes of amazing information, but most of the time you call out what nature tells you, » Banerdt said.
« It’s more like trying to follow a chain of disingenuous evidence than presenting us the answers in a nicely wrapped package. »
What are the three main INSIGHT tools?
Lander that could reveal how Earth formed: The InSight Lander set to land on Mars on November 26
Three main instruments will allow the InSight lander to « take the pulse » of the red planet:
Seismometer: The InSight Landing Vehicle is carrying a Seismometer, SEIS, who is listening to the pulse of Mars.
A seismometer records the waves that travel through the planet’s internal structure.
The study of seismic waves tells us what the source of the waves could be.
On Mars, scientists believe the culprits could be earthquakes or meteors hitting the surface.
Heat probe: The HP3 Heat Flow Probe digs deeper than any shovels, drills, or other probes on Mars before it.
It will look at how much heat is still flowing from Mars.
Radio antennas: Like Earth, Mars wobbles slightly as it orbits on its axis.
To study this, there are two radio antennas, part of the RISE instrument, which track the location of the probe very precisely.
This helps scientists test the planet’s reactions and tells them how the deep inner structure affects the movement of the planet around the sun.