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IMSE Faculty Featured on Hold That Thought

Hold That Thought features research and ideas from Arts & Sciences at Washington University in St. Louis. In order to provide a nuanced, multi-faceted view of complex ideas, we select topics to explore and then bring together thoughtful commentary on those topics from a variety of experts and sources.

Stories in Rocks

In his rock deformation laboratory here at Washington University in St. Louis, Phil Skemer applies huge amounts of heat and pressure to rock samples. Crushing rocks may sound just like fun, but he and his team are seeking answers to fundamental questions about how Earth works. Why does our planet have plate tectonics, when neighbors like Venus do not? To look for clues, Skemer uses - and builds - instruments that replicate the intense conditions found deep in the interior of the Earth.

Discovering Dark Matter

Back in the early 1930s, astronomer Fritz Zwicky discovered a problem. Zwicky studied galaxy clusters, which can contain hundreds to thousands of galaxies loosely bound together by gravity. While examining one such cluster, he realized that the visible material within the galaxies did not have enough mass to hold the cluster together. As a result, he inferred that some dark, unseen matter must exist. Decades later, Ramanath Cowsik theorized about the source of this extra gravitational force. Cowsik, who now directs the McDonnell Center for the Space Sciences, describes the history of dark matter and shares how his discovery changed the way scientists think about this invisible force in the universe. 

Nuclear Magnetic Resonance

With the help of scientists like Sophia Hayes, associate professor of chemistry, new technologies may make it possible to remove the greenhouse gas carbon dioxide from the atmosphere, turn it into a solid, and store it in a safe environment elsewhere. Hayes uses a technique called nuclear magnetic resonance (NMR) to understand the structure of materials, including carbon dioxide. Hear her describe this research project, explain how NMR works, and reveal how “the magic angle” – a Washington University innovation – changed the field.

The Search for Dark Matter

As we learned last week in Discovering Dark Matter, since the 1930s scientists have been seeking answers about unseen mass in the universe. We know that the gravitation of dark matter has an enormous effect on galaxies, and we also know that it may be made up of weakly interacting particles. But how do researchers search for something that's invisible? James Buckley, professor of physics at Washington University in St. Louis, has spent part of his career hunting for neutralinos, a yet-undiscovered type of particle that may hold the answer to the dark-matter mystery. Buckley describes the evidence for the existence of neutralinos, the methods he uses to seek them out, and how he first became interested in the "dark and violent" side of the universe.


Studying Stardust

Christine Floss, research professor in the physics department at Washington University in St. Louis, spends her time investigating microscopic specks of dust that have remained unchanged since before the formation of the solar system some 4.5 billion years ago. These presolar grains help researchers like Floss answer questions about the formation of elements, the solar system, and the universe as a whole. Floss describes how she and her students search for presolar grains in ancient meteorites, why tiny grains of silica are particularly fascinating, and how as an undergraduate geology major she first became hooked on outer space.