Big Idea: Measuring the dark matter that surrounds us

LUX-ZEPLIN brings 250 of the best minds together
Big Idea: Measuring the dark matter that surrounds us
Photo by Paulius Musteikis
Kimberly Palladino

Look around you and imagine: All you can see–rustling birch leaves, purring cat, your hand against your knee–is less than 5 percent of what’s actually there. According to researchers, the other 95 percent is either dark matter or dark energy, mysterious substances that do more than simply exist; they hold our universe together. Now the U.S. government has ramped up its efforts to measure dark matter, and a team of UW-Madison scientists is among those tapped to make it happen.

The LUX-ZEPLIN, or LZ, Dark Matter Experiment is a project funded by the U.S. Department of Energy and the U.S. National Science Foundation that brings together 250 of the best minds from 37 institutions around the world–nine of those elite scientists and engineers are from UW-Madison and Stoughton’s Physical Sciences Lab. Professor of physics Duncan Carlsmith is principal investigator of the UW-Madison team, flanked by senior investigator professor Sridhara Dasu and assistant professor and particle astrophysicist Kimberly Palladino.

“The big idea for dark matter detection is that it’s all around us right now, and it’s really important gravitationally, for how big structures–galaxies and bigger–form,” says Palladino. “We know it doesn’t interact with light and with charge, and it doesn’t really interact much with itself.”Big Idea: Measuring the dark matter that surrounds us

What it will interact with–theoretically, hopefully–is the 10 metric tons of ultra-purified liquid xenon floating inside the largest, most sensitive detector built to date, currently under construction at the Sanford Underground Research Facility in Lead, South Dakota. SURF is a lab built inside the abandoned Homestake Gold Mine (referenced in the final episode of HBO’s “Deadwood”), located nearly one mile underground. While the fast-tracked LZ experiment is slated to wrap up in 2020, its findings will likely lead to further experiments and even more big ideas.

“This is an outstanding mystery, and we know it’s there,” says Carlsmith, who’s as thrilled about the hunt as he is about passing on the work to future generations of researchers. “Science is exploration, it’s about people. You get results, but they’d be sort of meaningless unless there’s a whole community invested in it.”

Maggie Ginsberg is a senior contributing writer for Madison Magazine.

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