Why doesn’t Mars have a magnetic field? If it did, the planet would be protected from cosmic radiation and charged particles emitted by our Sun. With a magnetic field, perhaps the Red Planet wouldn’t be the dry, barren world it is today.
It has long been believed that Mars once had a global magnetic field like Earth does, but somehow the iron-core dynamo that generated it must have shut down billions of years ago.
But new seismic data from NASA’s InSight lander might change our understanding of Mar’s interior, as well as alter the view of how Mars evolved and changed over time. InSight’s data revealed the presence of a molten silicate layer overlying Mars’ metallic core. Scientists say this insulating layer is like a blanket that might prevent the core from producing a global magnetic field.
The ground shakes. Paintings tilt. Walls crack. Rubble may fall. On Earth, we understand how and where these events happen due to the discovery of plate tectonics – the continental crust’s creation, movement, and destruction. However, when astronauts placed seismometers on the lunar surface during NASA’s Apollo mission era, those instruments recorded quakes on the Moon. In the 1970s, the Viking landers also recorded quakes on the surface of Mars. Since neither of these worlds has plate tectonics, scientists set about collecting more data to understand the phenomena, which led to the recent NASA InSight lander. Now, a new paper in Geophysical Research Letters explains how the largest recorded seismic event on Mars provided evidence for a different sort of tectonic origin — the release of stress within the Martian crust.
How thick is the crust of Mars? This question is what a recent study published in Geophysical Research Letters attempted to answer as it reported on data from a magnitude 4.7 marsquake recorded in May 2022 by NASA’s InSight lander, which remains the largest quake ever recorded on another planetary body. As it turns out, this data helped provide estimates of Mars’ global crustal thickness, along with a unique discovery regarding the crust in the northern and southern hemispheres, and how the interior of Mars produces its heat.
More than a hundred years after geologists first observed how seismic waves traveled through Earth, they’ve achieved another seismic first. This time, they measured “core-transiting seismic waves” moving through Mars. The InSight lander’s seismic instrument tracked shockwaves generated by an earthquake and an impact event. Their behavior revealed for the first time that Mars very likely has a liquid core. It’s made of a single blob of molten iron alloy.
The InSight lander might have transmitted its last picture from the surface of Mars. It looks like the lander is succumbing to Mars’ dusty conditions, as its ability to generate energy from its solar panels has been declining in recent weeks.
It’s always sad and somehow poignant when a lander or a rover falls silent. Each of them has a personality that goes along with their mission. But we’ve known for months this day was coming.
However, a research team led by ETH Zurich recently analyzed a cluster of more than 20 recent marsquakes, which revealed something very interesting. Based on the location and spectral character of these events, they determined that most of Mars’ widely distributed surface faults are not seismically active. Nevertheless, most of the 20 seismic events observed originated in the vicinity of Cerberus Fossae, a region consisting of rifts (or graben). These results suggest that geological activity and volcanism still play an active role in shaping the Martian surface.
The Mars InSight lander might be nearing the end of its life on the Red Planet, but its scientific data are still shaking up the planetary science community. That’s because it detected another Marsquake on December 24, 2021. It was a major shaker and generated surface waves that rippled across the crust of the planet. The data from that quake allowed science team members to get a better idea of the Martian crust’s structure.
For the first time, a spacecraft has detected acoustic and seismic waves from impacts on Mars. NASA’s InSight lander made the detections from four meteoroids that crashed on Mars in 2020 and 2021. Ever since the mission landed on the Red Planet in 2018, scientists have been hoping to be able to detect impacts with InSight’s seismometer, which was mainly designed to sense Marsquakes. But these impacts are the first the lander has detected.
Space science doesn’t always go as planned. Sometimes when scientists think they’ve made a remarkable discovery that will make human expansion into the cosmos easier, they are just flat-out wrong. But the beauty of science is that it corrects itself in the presence of new data. The people responsible for planning future Mars missions will have to make just such a correction as new data has come in on the availability of water on the red planet. There’s not as much of it as initially thought. At least not around the equator where InSight landed.
The InSight Mars lander will cease science operations sometime in the next few months due to a decreasing power supply, mission managers said at a news conference on May 17. Martian dust covering the solar panels has reduced the amount of power to roughly 500 watt-hours per Mars day or sol. When InSight landed in November of 2018, the solar panels produced around 5,000 watt-hours each sol.
“At the end of the calendar year, we do anticipate having to conclude all InSight operations,” said Kathya Zamora Garcia, InSight’s deputy project manager said at the briefing, “not because we want to turn it off but unfortunately we don’t have the energy to run it.”