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During a recent excursion to the frozen plains of Antarctica, an international team of researchers discovered five new meteorites, including one of the largest ever found on the continent.
The rare meteorite is about the size of a melon but weighs 17 pounds (7.7 kilograms). The specimen is one of 100 of that size or larger discovered in Antarctica, a prime meteorite-hunting spot where more than 45,000 space rocks have been tracked.
Now the rare find is headed to the Royal Belgian Institute of Natural Sciences in Brussels, where it will be studied. And María Valdés, a research scientist at the Field Museum of Natural History in Chicago and the University of Chicago who was part of the expedition team, has kept some of the material for her own analysis.
Valdés’ area of focus is cosmochemistry. That “in general terms means that we use meteorites to study the origin and evolution of the solar system through chemical methods,” he told CNN. He will take your samples and use strong acids to dissolve them before using a process called calibrated chemistry to isolate the various elements that make up the rock.
“Then I can start to think about the origin of this rock, how it evolved over time, what type of parent body it came from, and where in the solar system that parent body formed,” Valdés said. “Those are some of the big questions that we try to address.”
Meteors strike Earth evenly across its entire surface, so Antarctica is not home to a disproportionately large concentration of them, Valdes indicated. But the pure white ice is an ideal backdrop for observing the jet black rocks.
The search for meteoroids is “really low-tech and less complicated than people might think,” Valdés said. “We are walking or driving a snowmobile, looking at the surface.”
But the team had an idea of where to look. A January 2022 study used satellite data to help narrow down the locations where meteorites were most likely to be found.
“The meteorites themselves are too small to be detected from space with satellites,” Valdés explained. “But this study used satellite measurements of surface temperature, surface slope, surface velocity, ice thickness, things like that. And it plugged (the data) into a machine learning algorithm to tell us where the best chances of finding meteorite accumulation zones are.”
Distinguishing a meteorite from other rocks can be a complicated process, Valdés said. The researchers are looking for a fusion crust, a glassy layer that forms when the cosmic object plummets through Earth’s atmosphere.
“Many rocks may look like meteorites, but they are not,” he said. “We call these meteor bugs.”
Another distinguishing feature is the potential weight of the specimen. A meteorite will be much heavier for its size than a typical rock on Earth because it is packed with dense metals.
The conditions that the researchers endured were grueling. Although Valdés and three other scientists carried out their mission during the continent’s “summer,” which offered 24 hours of daylight, temperatures still hovered around 14 degrees Fahrenheit (minus 10 degrees Celsius), according to a news release from the Field Museum.
The research team spent about a week and a half with a polar field guide, living in tents pitched on the frozen ground. Nevertheless, Valdés said that she and her colleagues also they spent time at a Belgian research station near the coast of Antarctica, where they enjoyed hot meals with cheese, such as fondue.
When it comes to future research, The good news, Valdés added, is that the five meteorites that she and her colleagues discovered on this expedition are just the tip of the iceberg.
“I’m looking forward to going back there for sure,” she said. “According to the satellite study, there are 300,000 meteorites, at least, waiting to be collected in Antarctica. And the larger (number of) samples we have, the better we can understand our solar system.”
The excursion was led by Vinciane Debaille, a professor at the Université Libre de Bruxelles in Brussels. She and Valdés were accompanied by Maria Schönbächler, a professor at the Eidgenössische Technische Hochschule Zurich, and a doctoral student. Ryoga Maeda from Vrije Universiteit Brussel and the Université Libre de Bruxelles.