The size of a melon: Rare meteorite weighing 7.7 kg is discovered in Antarctica

During a recent excursion to the icy plains of Antarctica, an international team of researchers discovered five new meteorites, among them one of the largest ever found on the continent.

The rare meteorite is about the size of a cantaloupe but weighs 7.7 kilograms. The specimen is one of only about 100 of its size or larger discovered in Antarctica, a prime location for meteorite hunting where more than 45,000 space rocks have been tracked.

Now, the exceptional find goes to the Royal Belgian Institute of Natural Sciences, in Brussels, where it will be studied. And Maria Valdes, a researcher at the Field Museum of Natural History in Chicago and at the University of Chicago, who was part of the expedition team, kept part of the material for her own analysis.

Valdes’ area of ​​focus is cosmochemistry. This “broadly means that we use meteorites to study the origin and evolution of the solar system through chemical methods,” she told CNN . She will take your samples and use strong acids to dissolve them before going through a process called calibrated chemistry to isolate various elements that make up the rock.

“Then I can start thinking about where this rock came from: how it evolved over time, what kind of parent body it came from, and where in the solar system that parent body formed,” Valdes said. “These are the big questions we try to address.”

on the hunt

Meteorites hit Earth evenly across its surface, so Antarctica doesn’t harbor a disproportionately large concentration of them, Valdes noted. But the pure white ice is an ideal setting for spotting the black rocks.

Hunting meteorites is “really low-tech and less complicated than people might think,” Valdes said. “We walk or drive a snowmobile, looking at the surface.”

But the team had an idea of ​​where to look. One January 2022 study used satellite data to help pinpoint where meteorites were most likely to be found.

“The meteorites themselves are too small to be detected from space with satellites,” explained Valdes. “But this study used satellite measurements of surface temperature, surface tilt, surface velocity, ice thickness — things like that. and connected [os dados] to a machine learning algorithm to tell us where are the most likely to find meteorite accumulation zones.”

Distinguishing a meteorite from other rocks can be a tricky process, Valdes said. The researchers look for the fusion crust, a glassy coating that forms as the cosmic object plummets through Earth’s atmosphere.

“Many rocks may look like meteorites, but they’re not,” she said. “We called these meteors wrong.”

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 the researchers went through were grueling. Although Valdes and three other scientists carried out their mission during the continent’s “summer”, which offered 24 hours of daylight, temperatures still hovered around -10 degrees Celsius, according to a press release from the Field Museum.

The research team spent about a week and a half with a polar field guide, living in tents set up in the icy terrain. However, Valdes said she and her colleagues also spent time at a Belgian research station near the coast of Antarctica, where they enjoyed hot, cheesy foods like fondue.

When it comes to future research, the good news, added Valdes, is that the five meteorites 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 at least 300,000 meteorites waiting to be collected in Antarctica. And the bigger [o número de] samples we have, the better we can understand our solar system.”

The tour was led by Vinciane Debaille, a professor at the Université Libre de Bruxelles in Brussels. She and Valdes were joined by Maria Schönbächler, a professor at the Eidgenössische Technische Hochschule Zurich, and doctoral student Ryoga Maeda, from the Vrije Universiteit Brussel and the Université Libre de Bruxelles.