During an expedition to Antarctica that ended Jan. 16, researchers found five meteorites, including one of the largest specimens recovered from the continent. (Maria Valdes)
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ATLANTA – During a recent excursion to the icy 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 cantaloupe but weighs a whopping 17 pounds. The specimen is one of only about 100 that size or larger to have been discovered in Antarctica, a prime location for meteorite hunting where more than 45,000 space rocks have been tracked down.
Now the exceptional find is going to the Royal Belgian Institute of Natural Sciences in Brussels, where it will be studied. And Maria Valdes, a research scientist at Chicago’s Field Museum of Natural History and the University of Chicago who was part of the expedition team, saved some of the material for her own analysis.
Valdes’ area of interest is cosmochemistry. That “broadly means that we use meteorites to study the origin and evolution of the solar system through chemical methods,” she told CNN. She takes her samples and uses strong acids to dissolve them before using a process called calibrated chemistry to isolate various elements that make up the rock.
“Then I can start thinking about the origin of this rock, how it evolved over time, what kind of parent body it came from, and where in the solar system that parent body originated,” Valdes said. “Those are kind of the big questions that we’re trying to address.”
Meteorites strike Earth evenly across the surface, so Antarctica isn’t home to a disproportionate concentration of them, Valdes noted. But the pure white ice is an ideal background to spot the jet black rocks.
Hunting meteorites is “really low-tech and less complicated than people might think,” Valdes said. “We walk around or ride a snowmobile and look at the surface.”
But the team did have an idea of where to look. A January 2022 study used satellite data to find locations where meteorites were most likely to be found.
“Meteorites themselves are too small to be detected from space with satellites,” explains Valdes. “But this study used satellite measurements of surface temperature, surface slope, surface speed, ice thickness — things like that. And it fed (the data) into a machine learning algorithm to tell us where the greatest probability is to find meteorite accumulation zones.”
Distinguishing a meteorite from other rocks can be a tricky process, Valdes said. Researchers are looking for fusion crust, a glassy layer that forms when the cosmic object crashes through Earth’s atmosphere.
“A lot of rocks can look like they’re meteorites, but they’re not,” she said. “We call these meteor errors.”
Many rocks may look like meteorites, but they are not. We call these meteor errors.
—Maria Valdes, Chicago Field Museum of Natural History
Another distinguishing feature is the weight of the potential specimen. A meteorite will be much heavier than a typical terrestrial rock for its size because it is full of dense metals.
The conditions the researchers had to endure were grueling. Even though Valdes and three other scientists conducted their mission during the continent’s “summer,” which offered 24 hours of daylight, temperatures still hovered around 14 degrees Fahrenheit, according to a Field Museum press release.
The research team spent about a week and a half with an Arctic field guide, living in tents on the icy terrain. However, Valdes said she and her colleagues also spent time at a Belgian research station near the coast of Antarctica, enjoying hot, cheesy foods, such as fondue.
When it comes to future research, the good news, Valdes added, is that the five meteorites she and her colleagues discovered on this expedition are just the tip of the iceberg.
“I can’t wait to go back there, for sure,” she said. “Based on the satellite study, there are at least 300,000 meteorites waiting to be collected in Antarctica. And the larger (number of) samples we have, the better we can understand our solar system.”