It’s the “big one”. An earthquake of unprecedented magnitude was detected on May 4 by an instrument installed far away from the equator. No casualties or material damage to report. And for good reason. This earthquake was actually an earthquake on Mars.
Captured by NASA’s Insight Probe, the 5 magnitude vibration is the largest vibration recorded on extraterrestrial ground. Although it is far from the highest measured in the world – 9.5 in Chile in May 1960. “An earthquake (of this magnitude) is considered moderate on Earth, but it represents the upper limit of what scientists expected to measure,” the US space agency Planet said in a statement.
On Mars, the earth does not vibrate for the same reason as our planet. On Earth, the most powerful earthquakes are caused by the tectonics of the Earth’s crustal plate. They collide, rub, overlap or move away and it is this movement, which is fueled by the heat of the earth’s crust, that causes the vibrations.
More than 1,300 tremors were detected
“Mars has no tectonic plates,” NASA explained on the Insight mission site in July 2021. Rather, its crust appears to consist of a single giant slab. But the pressure caused by the planet’s slight contraction could cause errors or rock cracks, which would continue to cool. “
In other words, if terrestrial earthquakes are caused by the movement of a planet that is still alive, then Mars earthquakes are the result of its slow geological death, which began 3.5 billion years ago and contains remnants of ancient volcanoes. The most visible witness. This explains the significant difference in the strength of the most anticipated shocks.
Landing on Mars in the fall of 2018 and active since February 2019, Insight has detected more than 1,300 vibrations since launching its mission, thanks to the highly sensitive Seismometer SEIS produced in France by the National Center for Space Studies (CNES). .) The previous record for the summer of 2021, with two tremors of 4.2 magnitude, one month apart.
For mission scientists, the stronger these earthquakes, the more promising they are. Insight was sent to Mars to give the first picture of the red planet’s soil. Seismic waves change speed and shape, depending on the material they pass through. Their study may answer about the formation of different layers beneath the surface.
This information is even more valuable as it provides a better idea of the formation of rocky planets, including Mars and our Earth, which contains dust and misguided debris in the primitive solar system. They could also explain the rapid cooling of the Red Planet and the damage it caused to its atmosphere, which turned it into an uninhabited desert.
Analysis of the first 733 earthquakes recorded by Insight – including 35 with a magnitude of 3 – has already yielded results, published in the July 2021 issue of the journal “Science”. The internal structure of Mars was then revealed, with a crust 20 to 37 kilometers thick, a mantle over 1,500 kilometers, and a core 1,800 kilometers in diameter.
“This is a once-in-a-lifetime study,” said Simon Stallhar, co-author of the study at ETH, a Swiss research university in Zurich. It took hundreds of years to measure the core of the Earth (editor’s note, with a total diameter of 3,500 km), and more than 40 years for the moon after the Apollo mission. Insight only takes two years to measure Mars. “
Insight’s Swan Song
However, scientists still hoped for the “Big One”, the quake has reached the limit of what can be observed. This is done now, with these 5 magnitude vibrations. This earthquake will give us a view of the interior of the planet that has never been seen before. We have enough information to analyze over the years. “
The identification of this jolt could be Insight’s Swan Song. Scheduled to work for two years, the probe saw NASA extend its lifespan with the new December 2022 deadline. However, it is not certain whether it will be successful. Its solar panels are bound by the dust of Mars, and its power generation is ten times less than it started now.
On May 7, three days after the capture of the “Big One”, the available power levels dropped below the security threshold, shutting down all non-critical functions. On May 17, the U.S. space agency said science activities would be shut down in the summer and that the priority would be to retrieve the latest data.
Insight’s only lifeline will be an imaginary Mars clock that will “clean” its photovoltaic cells. Otherwise, the search will stop working within a few months, with a sense of accomplishment. “Insights have changed our understanding of the interior of rocky planets,” said Laurie Glaze, NASA’s director of planetary science. We can apply what we have learned about the internal structure of Mars to the Earth, the Moon, Venus and even the other solar system on the rocky planet. A