The world has heard the first faint whispers of the most powerful cataclysms in the universe. Scientists working on the IceCube experiment in Antarctica report that they have found 28 neutrinos that must have come to earth from explosions in the distant universe—the first time scientists have found neutrinos coming from outside our own solar system. We wrote about the detections in the November issue of Scientific American, but the researchers have just now published their results in the journal Science. The results open up a new era of astronomy, allowing researchers to study not just the light from distant objects, but the fundamental particles that they generate as well.
The IceCube detector is itself a marvel of engineering. It consists of a three-dimensional grid of over 5,000 sensitive photodetectors suspended in the glacial ice beneath the South Pole. As a neutrino speeds through the grid, it occasionally bumps directly into an atom, setting off a tiny flash of light. The photodetectors pick up this tiny flash, and the data can be used to reconstruct the energy and direction of the neutrino that started it all. Here's a short clip showing how light from one of the highest-energy neutrinos, nicknamed "Ernie," passed through the detector:
The researchers next want to try to identify a specific spot on the sky where these high-energy neutrinos are coming from. If they could observe a high-energy event with both ordinary telescopes and neutrino eyes, they could gain a much richer understanding of the mysterious dynamics at the cores of the universe's most extraordinary events.
[Image courtesy of Sven Lidstrom, IceCube/NSF, March 2012]
[First video courtesy of the IceCube Collaboration]
[Second video courtesy of University Communications/University of Wisconsin–Madison]