Meteorites that hit Earth don’t always come from the deepest parts of the solar system, sometimes they come from the closest planets. In fact, over the years, researchers have found hundreds of rocks that originated on Mars. Experts now believe that about 200 of those meteorites came from five specific impact craters in two volcanic regions on the Red Planet. With further analysis, researchers believe that these samples could help us better understand the geological history of Mars.
Previous attempts to pinpoint the origins of Martian meteorites have proven largely unsuccessful, relying on a technique called spectral matching, which compares the composition of materials based on the patterns of light they can emit or absorb. But trying to do this for dusty sources millions of miles away makes the results unreliable and difficult to obtain.
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But a study published in the journal Nature on August 16th found that Scientific advancesA research team from the University of Alberta has calculated that about half of the 10 subgroups of Martian meteorites identified on Earth come from specific regions on Mars. The discovery is based on improved modeling of the physics of Mars, which is key to understanding the ejection process caused by asteroid impacts. The researchers combined this better understanding of ejection dynamics with remote sensing data detailing the geological structure of Mars to narrow down the meteorites’ origin.
This “major advance” allows researchers to revise previous, limited calculations, according to study co-author Chris Hurd, professor of earth and atmospheric sciences and curator of the University of Arizona’s meteorite collection.
“I call this the missing link – to say that the conditions that released this meteorite were met by an impact event that created a crater 10 to 30 kilometers (about 16 to 38 miles) in diameter,” he said. University statement August 19th.
One might think that only a relatively gigantic impact would be strong enough to fling chunks of the planet out of its atmosphere, but that’s not actually the case. But thanks to ejection speeds of 5 kilometers per second (8 miles per second), an explosion that would only create a crater 5 miles wide could theoretically be strong enough to send rocks escaping Mars’ gravity, orbiting the Sun, and eventually being attracted to Earth. Astronomers believe that there have been 10 events in Mars’ recent history that have sent debris flying into space.
“We can now classify these meteorites by their common history and their location on the surface before they came to Earth,” Hurd explained.
Researchers now believe that five craters spread across two volcanic regions known as Tharsis and Elysium are the likely source of the roughly 200 meteorites detailed in the study.
This new information will allow researchers to begin revising the Martian chronology, which could affect the timing, duration and details of many individual planetary events since Mars’ birth. Hurd said further analysis could also allow them to reconstruct Mars’ volcanic stratigraphy, or the record of the planet as seen through its geological layers.
“This will fundamentally change how we study meteorites from Mars,” Hurd said.
