Scientists have identified about 166 Martian meteorites that have landed on Earth over the past 20 million years. But their origins have remained a mystery not until a team of researchers from Curtin University pinpoint their likely home on Mars before getting ejected.
The team used a machine learning algorithm that analyzes high-resolution planetary images to identify the origins of the Martian meteorites. They published their study, titled "The Tharsis Mantle Source of Depleted Shergottites Revealed by 90 Million Impact Craters," in Nature Communications.
Martian meteorites in Vienna Natural History Museum, Austria, 2014 (Photo by: Zachi Evenor)
Martian Meteorites
In the past, people have no idea that some meteorites come from Mars, given that there are thousands of meteorites that land on Earth. According to National Geographic, NASA's Viking spacecraft, which successfully landed on the Red Planet in the 1970s, has given scientists a hint that some meteorites that landed on Earth may have come from Mars.
The spacecraft measured chemicals in the Martian atmosphere and its surface, which matched the trapped gases that they found on some of the meteorites on Earth.
Scientists believe that Martian meteorites were formed when asteroids and other space rocks hit the surface of the Red Planet millions of years ago. These collisions formed an impact crater and sent tons of rocks and dust into the planet's atmosphere, but the more violent collisions have sent debris out of Mars' gravitational field and into outer space in a process called spallation.
These rocks likely drifted into space for millions of years before getting sucked in the Earth's gravitational field, as evident from the cosmic ray exposure (CRE) that scientists have measured on the Martian meteorites.
Due to its high exposure to cosmic rays, some elements on the space rocks became unstable isotopes, which decay at predictable rates and allow scientists to accurately estimate the time they spent in the Martian atmosphere and Earth.
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Origins of Martian Meteorites That Landed on Earth
Study lead researcher Dr. Anthony Lagain said in the university's press release that they used a machine learning algorithm for their study to compile a new database of 90 million impact craters that will help them identify the possible launch positions of Martian meteorites.
They studied the small craters formed by the ejecta that was recently formed on the surface of the Red Planet and found that Martian meteorites may have come from the Tooting crater in the Tharsis region. Phys.org reported that these Martian meteorites were ejected from the planet 1.1 million years ago.
They credited their findings to the machine learning they used, which was developed in-house by an interdisciplinary group of experts using the fastest supercomputer in the Southern Hemisphere, the Pawsey Supercomputing Centre, and the Curtin HIVE (Hub for Immersive Visualisation and eResearch).
The team said that this research had made the geological context of a group of meteorites accessible a decade before NASA's Mars Sample Return mission that will send back samples of Martian rock collected by the Perseverance rover. Dr. Lagain noted that their findings would help create a better understanding of the evolution and formation of Mars and Earth.
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