Hunting Neutrinos in Antarctica

Spencer Klein is holding a thick glass ball the size of a watermelon and it is stuffed with electronics. For 10 minutes or so, he turns it over in his hands and talks through what it does, how it works and the brutal environment it can withstand. This last point turns out to be key. Over the past half-decade, more than 5,000 of these objects have been shipped to the south pole, strung together like beads, and buried deep in the Antarctic ice sheet.

Klein is a physicist at the Lawrence Berkeley National Laboratory that sits high on the hills overlooking the University of California's Berkeley campus and beyond to San Francisco Bay. The glass ball in his hands is a "digital optical module" (DOM), an exquisitely sensitive light detector that lies at the heart of what must be one of the most ambitious projects in the history of science. By freezing these modules into the ground around the US Amundsen-Scott south pole station, on the high plain of Antarctica, Klein and his colleagues have turned a cubic kilometre of pristine polar ice into an enormous cosmic observatory.

The $272m (£170m) IceCube instrument is not your typical telescope. Instead of collecting light from the stars, planets or other celestial objects, IceCube looks for ghostly particles called neutrinos that hurtle across space with high-energy cosmic rays. If all goes to plan, the observatory will reveal where these mysterious rays come from, and how they get to be so energetic. But that is just the start. Neutrino observatories such as IceCube will ultimately give astronomers fresh eyes with which to study the universe.…

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