Mark Thiemen's office seems more like a museum than a place to do work. Artifacts from his global travels are tucked away between brimming bookshelves. Prayer flags from Tibet drape one side of the room. On the other, a meteorite sits under a plastic cover.
Thiemens is a professor of chemistry at UC San Diego. He’s spent decades studying isotopes, elements with a different number of neutrons, in remote places. Now, he is being awarded with America's oldest science prize.
“Truthfully it was humbling,” Thiemens said. “It was very — It was great, what can I say?”
The American Philosophical Society bestowed Thiemens with the Magellanic Premium, an honor that has only been given out 43 times in 240 years. It is awarded to researchers who fundamentally shift what scientists know about the natural world. Patrick Spero, who is the CEO of the society, notes that Thiemens’ work spans from understanding the origins of the universe to solving modern problems like greenhouse gas emissions.
“In the end it was absolutely unanimous that he should receive it,” Spero said. “As we looked at the scope of his research and the various areas that it had impact we realized that this was transformative research that was fundamental in its nature.”
Thiemens’ most notable discovery was mass independent isotope fractionation (MIF). The technique helped measure oxygen isotopes in meteorites.
Before MIF, scientists believe that certain features on meteorites were caused by exploding stars. But Thiemens’ MIF method showed that small white dots on the space rocks were actually evidence of a chemical process.
The discovery shifted what scientists originally assumed about the earth’s origin, and showed that earth may not have been created by a singular exploding star event.
“The different species (of isotopes) coming up, it tells you a lot,” Thiemens said. “Those papers added to what those people know in a serious way.”
His work also contributed to protecting the earth’s atmosphere in the early 90s. After collecting samples from the atmosphere, he and his colleague Bill Torgler noticed large amounts of nitrous oxide in the environment. The gas is known to be harmful to the ozone layer and was a byproduct of manufacturing nylon.
At the time, greenhouse gas emissions were not regulated. But after his study was published one of the largest producers of synthetic nylon, Dupont, adjusted their nylon making process to stop generating nitrous oxide.
Thiemens said the breakthrough significantly cleaned up the atmosphere. That’s equivalent to about 10 million pounds of carbon dioxide emissions today.
“That one I’m proud of,” Thiemens said. “I can’t think of a paper that led to a change in climate species more than that.”
His work continues to contribute to understanding how the earth’s climate is changing. Thiemens plans on using isotopes to investigate how the ice is melting in the Himalayas, which could impact global drinking water supplies.
