NASA’s Mars Insight probe detected seismic waves from four space rocks that crashed on Mars in 2020 and 2021.
Not only do these represent the first forcings detected by the spacecraft’s seismometer since Insight landed on Mars in 2018, but they also mark the first time that seismic and sonic waves from a collision have been detected on the Red Planet — a development that provides scientists with a new clue. A method for studying Mars’ crust, mantle and core.
A new study was published in natural earth sciences—in which Ingrid Daubar, assistant professor at Brown University (research) in Earth, Environmental and Planetary Sciences, co-authored, details impacts ranging from 53 to 180 miles from InSight, a region of Mars called Elysium Planitia.
“It was very exciting,” Daubar recalls the influences. “My favorite pictures are those of the pits themselves. After three years of waiting for the effect, those pits looked beautiful.”
Of the four confirmed meteorites, which is the term used for space rocks Before they hit Earth, the first thing the team found was the most exciting entrance: It entered Mars’ atmosphere on September 5, 2021, and exploded into at least three fragments that each left craters behind.
When NASA’s Mars Reconnaissance Orbiter flew over the estimated impact site to confirm the location, it used a black and white context camera to detect three dark spots on the surface. After locating these spots, the orbiter team used the high-resolution imaging science experiment camera to obtain a color close-up of the craters. There is also sound for effects available.
After combing through past data, three more impacts were confirmed to have occurred on May 27, 2020; February 18, 2021; and August 31, 2021.
“Having a really accurate location for the source of the effects calibrates all the other data for the mission,” Dubar said. “This validates the estimates we’ve made and will allow us to do it more accurately… It also tells us a lot about the impact process itself and the seismic outcomes. We’ve never really seen this before.”
Researchers have puzzled over why they haven’t discovered more meteorite impacts on Mars. The red planet It is located next to the main asteroid belt of the solar system, which provides an ample supply of space rocks to wreak havoc on the planet’s surface. Since Mars’ atmosphere is only 1% as thick as Earth’s, more meteorites pass through it without disintegrating.
Furthermore, InSight’s seismometer has detected more than 1,300 “swamps”. The French space agency, the National Center for Space Studies, provides the instrument so sensitive that it can detect seismic waves from thousands of miles away. But the event of September 5, 2021 marks the first time that an effect has been detected.
The InSight team suspects that other effects may have been masked by wind noise or seasonal changes in the atmosphere. Now that the distinctive seismic signature of an impact on Mars has been discovered, scientists expect to find more hiding within nearly four years of the InSight data.
passion for planets
For Daubar — who in addition to her role at Brown is a research scientist at NASA’s Jet Propulsion Laboratory who leads the impact drilling working group on the InSight mission — she sees the potential of the data to enable further study of other planets, including Earth.
“In a broader sense, the reason we study other planets is to better understand our own planet,” she said.
Daubar was an assistant professor of planetary sciences at Brown University for three years, but her cosmic curiosity arose much earlier.
“I was lucky enough to have public high school In East Lyme, Connecticut, there was a planetarium. “It sparked my interest in astronomy and space.”
In college, she majored in astronomy at Cornell University. I went on to get my Ph.D. He received his Ph.D. in planetary sciences at the University of Arizona and became a researcher at the Jet Propulsion Laboratory.
“I love digging,” Dubar said. “I think it’s one of the most exciting planetary processes we can study.”
She said Dubar is among several hundred scientists and engineers around the world contributing to the Insight mission.
She said, “I’m a visual person and I’ve worked on cameras a lot, so for me having visual evidence of this physical phenomenon is really exciting. We already have ‘before and after’ pictures.” It’s so cool to me that the surface of this plant is changing now. It’s not practical ancient geology.”
The science behind the strikes
Data from meteorite collisions provide various clues that will help researchers better understand Mars.
“We have tons of data, which is really exciting for scientists,” Dubar said. “We’ve explored the planet a lot. There’s a lot we know – and a lot we don’t.”
Most earthquakes occur because subsurface rocks are fractured by heat and pressure. Studying how the resulting seismic waves change as they move through different materials provides scientists with a way to study Mars’ crust, mantle, and core.
The four impacts confirmed so far have caused small earthquakes of no more than 2.0 magnitudes. This does not provide scientists with a deeper glimpse into Mars’ crust, while seismic signals from larger earthquakes, such as the magnitude-5 earthquake in May 2022, could reveal details of the planet’s atmosphere and core.
“These special effects are really small and close — they didn’t go through the mantle and core,” Dubar said. “But it allows us to use this knowledge of the entire list of events with new understanding from these data points about location and source.”
Most importantly, the effects will be crucial to improving the timeline of Mars.
“The effects are the clocks of the solar system,” said Rafael Garcia, of the Higher Institute of Electricity and Space in Toulouse, France, who is the study’s lead author. “We need to know the impact rate today to estimate the age of the different surfaces.”
Scientists can estimate the age of the planet’s surface by calculating its impact craters. On Mars, the surface has had more time to accumulate impact craters of various sizes because the planet lacks the movement of tectonic plates and active volcanoes that constantly renew the surface, as happens on Earth. By calibrating statistical models based on how often they see impacts occurring now, scientists can estimate how many additional impacts occurred earlier in the history of the solar system.
“Seismology is one way we can learn what’s inside the planet,” Dubar explained. “The InSight mission is the first to actually study the interior of the planet.”
InSight data, in conjunction with orbital images, can be used to reconstruct the trajectory of a meteorite and the magnitude of the shock wave. Each meteor creates a shock wave when it hits the atmosphere and explodes when it hits the Earth. These events send sound waves through the atmosphere. The larger the explosion, the more this sound wave tilts the Earth when it reaches InSight. The lander’s seismometer is sensitive enough to measure how far and in what direction the Earth is tilted from such an event.
“We are learning more about the impact process itself,” Garcia said. “We can now match different sizes of craters to specific seismic and acoustic waves now.”
Rafael Garcia, newly formed craters on Mars located using seismic and sound wave data from InSight, natural earth sciences (2022). DOI: 10.1038 / s41561-022-01014-0. www.nature.com/articles/s41561-022-01014-0
the quote: NASA’s InSight hears the first meteor impacts on Mars (2022, September 19) Retrieved September 19, 2022 from https://phys.org/news/2022-09-nasa-insight-meteoroid-impacts-mars.html
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