Bad astronomy | NASA’s InSight lander has felt earthquakes on Mars –

Bad astronomy | NASA’s InSight lander has felt earthquakes on Mars

NASA’s Mars InSight lander just detected two more relatively large earthquakes on the Red Planet, and they came from the direction of a very interesting region known to be tectonically active. This highlights one of the biggest questions we have about Mars: Is it volcanically active today? I like, now?

InSight landed on a volcanic plain called Elysium Planitia on November 26, 2018. Its main mission is to study the interior of Mars using seismographs, a heat probe, and radio signals to determine the planet’s structure. It also has a weather station to measure temperature, wind and pressure (you can also get a daily report).

The heat probe, unfortunately, never really got a chance to work; It was designed to cut its way about 5 meters above the surface, but despite some pretty heroic efforts, it never got very far, and that part of the mission ended.

However, the seismic package has worked wonderfully and more than 500 earthquakes have been detected. When something shakes, rattles, and rolls on Mars, it creates sound waves called seismic waves that move through the interior of the planet. Different types of waves move differently, helping scientists understand the interior of Mars. Most of the waves InSight has detected are high-frequency surface waves that come from some event in the crust of Mars, but several dozen are lower frequency and can propagate through the mantle of Mars (which, like Earth’s , it’s solid, but not as hot and probably won’t move like ours does).

During the first year on Mars (which lasts two Earth years) it detected two earthquakes of decent size, magnitude 3.5 and 3.6. Then, for a while, InSight didn’t detect many greats. This is probably because in the Martian winter the air is too unstable and the noise of the wind masks the seismic activity. SEIS, the seismic detector, sits under a small dome deployed by InSight to protect it from the wind, but that can only go so far.

Now, with the Martian spring in the northern hemisphere, things have calmed down in terms of the atmosphere, and in March SIX it detected two more relatively large earthquakes, of magnitude 3.1 and 3.3. I’ve been through a few earthquakes when I was living in California, and that’s definitely big enough to feel it, though not big enough to cause any damage.

All of these earthquakes came from the direction of Cerberus Fossae, a series of depressions and cracks in the Martian crust about 1,600 km east of InSight. This region is very cool: The cracks probably formed a long time ago when the huge Tharsis volcanoes formed, creating a huge bulge in the crust. This extension of the crust caused the surface to crack into Cerberus Fossae, like a balloon covered in dried mud that will crack and separate if inflated.

What makes that area so interesting is that the surface around it is young, and I mean young: crater counts indicate it is less than 10 million years old, and some parts may be closer to 2 million. . A large volume of liquid gushed out of the ground at the time, possibly water, although it may have been lava, and made its way through the region.

A few million years is a tiny fraction of the 4.5 billion year old of Mars, which means that the planet was volcanically active very recently. Is it still today? That’s a question we’d love to answer, and InSight can help. These great earthquakes indicate something it’s happening there.

InSight recently received a mission extension until at least December 2022, which is great news. Scientists hope to detect more earthquakes over time, of course, and they also hope to reduce the noise that SIX feels so that they can detect weaker earthquakes (you can even feel the change in the ground as it cools during brief solar eclipses caused by the Phobos, Martian Moon!). On recordings made where seismic waves are turned into sound, you may hear some short, sharp bursts (collectively called, seriously, babies and donkeys). Here can one near the beginning of this recording of Sun 173*:

At first it wasn’t clear what they were, but now engineers believe they come from thermal movement in the cable that connects the SEIS to the lander, when large changes in temperature cause it to expand and contract. They plan to use a shovel on the lander to dig up some of the surface and drop it onto the cable, insulating it a bit. Hopefully that will hide some of the noise and improve the quality of the detections. You can see their efforts in this short video composed of a series of images taken by a camera on the lander:

It is amazing what you can learn about a planet by sitting very still on it and carefully feeling the movement. It’s great that we’re discovering the structure of Mars beneath its crust, but I’m particularly interested in whether Mars is still volcanically active. No one knew if Mars had any activity on it until relatively recently, and for most of my life it was thought to be a dead world. Now even though it may just be mainly dead, with a little kick still in him.

*Mars rotates once every 24 hours 37 minutes, so that’s the length of your day. To avoid confusion with Earth days, we call those suns, and they are numbered from the moment a given mission lands starting from 0, so in this case, Sol 173 was the 174th Martian day after InSight landed.


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