The laws of chemistry get pushed to the limits in Jenny Bergner’s astrochemistry lab at the University of California, Berkeley, where she is pondering some of the biggest questions in the universe: How do planets form? And how did life arise in the first place? To do so, she leads a team studying the exotic chemistry that happens under the crushing cold and near-perfect vacuum of interstellar space.
Using observatories such as the James Webb Space Telescope and the Atacama Large Millimeter/submillimeter Array in Chile, Bergner’s group collects the spectral fingerprints of molecules that are present in environments where planets are forming. She complements the telescope data with lab experiments, placing molecules in an ultracold, ultralow-pressure vacuum to form disordered, porous ices similar to those found in space. Next she and her co-workers bombard that ice with photons to mimic the radiation of interstellar space. “Then we can understand, at a molecular level, what reactions are taking place,” she says. These reactions could influence how planetary bodies form as their molecular components start to coagulate.
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Christie Hemm Klok
Bergner’s research came into public view in 2023, when she and a colleague published a paper in Nature offering new reasoning for the behavior of ‘Oumuamua, the first interstellar object ever observed passing through our solar system. It puzzled astronomers because it accelerated as it left the solar system in a way that comets, for example, typically do not. Scientists speculated about exotic explanations, including alien spacecraft. Bergner’s answer was less dramatic and, to her, far more satisfying: hydrogen gas, trapped within ‘Oumuamua’s icy interior by cosmic radiation over millions of years, warmed up as the object passed near the sun and escaped, propelling the object forward. No mystical thinking required—just the rules of chemistry playing out in interstellar conditions.
“Saying something is caused by magic is a much less interesting explanation to me,” Bergner says. The thrill of discovery, she adds, comes from using the rules of science to explain the phenomena that we see, no matter how strange.
This article is part of “The Young American Scientists,” an editorially independent project that was produced with financial support from Regeneron. Special thanks to the Exploratorium in San Francisco, where Bergner's portrait and video interview were captured.