22.11.2017
A First Look at How the Earth Stops High-Energy Neutrinos in Their Tracks
Neutrinos are abundant subatomic particles that are famous for passing through anything and everything, only very rarely interacting with matter. About 100 trillion neutrinos pass through your body every second. Now, scientists have demonstrated that the Earth stops very energetic neutrinos—they do not go through everything. These high-energy neutrino interactions were seen by the IceCube detector, an array of 5,160 basketball-sized optical sensors deeply encased within a cubic kilometer of very clear Antarctic ice near the South Pole.
IceCube’s sensors do not directly observe neutrinos, but instead measure flashes of blue light, known as Cherenkov radiation, emitted by muons and other fast-moving charged particles, which are created when neutrinos interact with the ice, and by the charged particles produced when the muons interact as they move through the ice. By measuring the light patterns from these interactions in or near the detector array, IceCube can estimate the neutrinos’ directions and energies.
