A 10-pound rock fell to Earth in Sherghati, India, in 1865. After being recovered, the rock passed to a British magistrate who tried to identify its source. Researchers in the 1980s confirmed that the rock, called shergottites, came from Mars.
According to the International Meteorite Collectors Association (IMCA), about 188 meteorites on Earth have been confirmed to be from Mars. But how these Mars meteorites got here is a question.
Designated Northwest Africa (NWA) 7034, and nicknamed "Black Beauty," the Martian meteorite weighs approximately 11 ounces (320 grams). Credit: NASA
Simulating the Arrival of Mars Meteorites on Earth
Researchers from the California Institute of Technology (Caltech) and the Jet Propulsion Laboratory (JPL) found that the shock pressure required to launch rocks from Mars into space is much lower than originally thought. Astronomers stated in a news release that they performed tests in which they shattered plagioclase-containing rocks from the Earth to examine how the mineral evolves under pressure.
They utilized a powerful "gun" to blast rocks with projectiles traveling over five times the speed of sound to simulate Martian impacts in shock-recovery experiments. The study, titled "Shock-recovered maskelynite indicates low-pressure ejection of shergottites from Mars," is described in a paper published in the journal Science Advances on May 3.
Until humans are able to return samples from Mars, the only parts of the Red Planet that have been discovered on Earth are Martian meteorites like the Shergottites. These boulders survived the impact's enormous heat and pressures and traveled across space, until crashing-landing on Earth.
The study was carried out in the laboratory of Eleanor and John R. McMillan Professor of Geology and Geochemistry Paul Asimow. In shock-recovery experiments, the team developed a more accurate method for simulating Martian impacts.
Previous shock-pressure tests required bouncing shock waves through a steel chamber, which provides an incorrect representation of what happens during a Mars impact event. The researchers discovered that far less pressure is required to launch a Mars meteorite than previously anticipated.
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How To Know If These Meteorites Are From Mars?
Researchers used the powerful blast gun to smash plagioclase-containing rocks from Earth and observe how the mineral transformed under pressure, developing a more accurate method to simulate Martian impacts, Universe Today reported.
They found that the pressure required to launch a rock from Mars into space is much lower than originally thought, around 20 gigapascals (GPa), rather than the previously accepted figure of 30 GPa.
The team suggested that the difference between 30 GPa and 20 GPa is significant, as the more accurately the shock pressures experienced by a meteorite can be characterized, the more likely it becomes that the impact crater on Mars from which it originated can be identified.
Martian meteorites can be traced back to the Red Planet because they contain pockets of trapped gas that match data from missions to Mars. In the late 1970s, NASA's Viking orbiters made measurements of Mars's atmospheric composition, which matched up with the gases encapsulated in the meteorites.
The study follows a previous paper published in 2022 that was able to pinpoint the origins of the "Black Beauty" meteorite from Mars, from an impact crater in the Terra Cimmeria - Sirenum region on the Red Planet. The new research is expected to help scientists determine where Martian meteorites originate and provide insights into the history of Mars.
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