The IceCube lab in Antarctica has finally found the first signs of cosmic neutrinos, created in the Universe’s most violent events.
Neutrinos in general are particles that barely interact with anything, casually passing through us, the Earth, and pretty much anything else in their way. Cosmic neutrinos in particular, though, are formed when some seriously energetic stuff happens in the far reaches of the universe: gamma ray bursts, black holes and the centres of galaxies.
These particles are incredibly difficult to detect, as they don’t tend to interact with anything, but the IceCube detector – buried deep under Antarctic ice – has now found 28 definite high-energy neutrino signatures, a massive step forward to being able to pinpoint their high-energy sources – because the neutrinos don’t interact with anything, they point in a straight line to their source.
In the detector itself, 86 strings of light detectors have been lowered into holes in the ice, between 1.5 and 2.5 km deep. When neutrinos do, rarely, interact with nuclei within the ice, this creates a chain reaction of light-emitting particles, which can be picked up by the detectors: and the brighter the light detected, the more energy the neutrino had.