Context: Francis Halzen awarded the Nobel Prize in Physics for contributions to the IceCube Neutrino Observatory and discovery of high-energy astrophysical neutrinos.
IceCube: Neutrino observatory located at the South Pole, embedded in Antarctic ice.
Purpose: Detects high-energy neutrinos of astrophysical origin from violent cosmic events.
Why Ice: ~1 cubic kilometre of clear, undisturbed ice provides a large detection medium and low interference.
Detector:5,160 optical sensors detect flashes of Cherenkov light produced during neutrino interactions.
Completed:2010.
First high-energy cosmic neutrinos reported:2013.
2018: IceCube traced a high-energy neutrino to a distant blazar.
Neutrinos: Electrically neutral, extremely weakly interacting elementary particles → can pass through matter almost unhindered. Produced in nuclear reactions, stellar processes and violent astrophysical events. Their weak interaction makes them difficult to detect.
Cherenkov Effect: Blue light emitted when a charged particle travels through a medium faster than light travels through that medium. It does not mean the particle exceeds the universal speed of light in vacuum.
Blazar: Active galaxy with a supermassive black hole whose relativistic jet is directed approximately toward Earth.
Neutrino astronomy: Uses neutrinos to study cosmic phenomena that may be difficult to observe through electromagnetic radiation alone.
