Emily Chan
For a long time, scientists have had differing opinions on how dinosaurs went extinct. Many believe that a giant asteroid was the culprit, slamming into the earth and wiping out the majority of life on the planet 66 million years ago. Others are more confident that massive volcanic eruptions killed off all the dinosaurs.
Recently, a new study has been conducted that may put an end to this ongoing debate. Researchers at Dartmouth College removed scientists from the discussion, eliminating human bias and letting the computers settle the argument instead.
A graduate student named Alex Cox and an assistant professor of earth sciences, Brenhim Keller, tested out a new modeling method powered by interconnected processors. Without the help of human input, the processors are able to analyze heaps of geological and climate data.
Cox and Keller used almost 130 processors to reverse-engineer the fossil record and determine what conditions led to the Cretaceous-Paleogene (K-Pg), which was the extinction event that paved the way for mammals to rule the earth.
They were motivated to create the model because they wanted to assess the question of the dinosaurs’ demise without a predetermined hypothesis, which is how experiments usually start. But instead, they took the opposite approach.
“Most models move in a forward direction. We adapted a carbon-cycle model to run the other way, using the effect to find the cause through statistics, giving it only the bare minimum of prior information as it worked toward a particular outcome,” said Cox.
The model generated more than 300,000 possible results regarding carbon dioxide emissions, sulfur dioxide output, and biological productivity in the one million years before and after the K-Pg extinction event.
The processors recalculated, edited, and modified their conclusions until they landed on a scenario that matched what the fossil record showed. They completed the task through a kind of machine learning called Markov Chain Monte Carlo, which is similar to how a smartphone predicts what you’ll type next.
The fossil record contained geochemical and organic residue that depict the conditions that dinosaurs suffered through before becoming extinct. The food chain was broken as plants and animals all over the world were destroyed as the climate fluctuated from weather that was unbearably hot to temperatures that were below freezing.
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