IceCube Provides First Evidence of Astrophysical Neutrinos From Cosmic Sources

The IceCube Neutrino Observatory, a particle detector buried in the Antarctica ice, detected 28 high energy particle events at Earth's South Pole marking the first solid confirmation for astrophysical neutrinos coming from cosmic sources.

The massless particles that flow to Earth at the speed of light from outside our solar system were detected by the detector buried in the Antarctic Ice. These massless particles collide with the surface of the Earth in a burst of energy. The particles were located in a block of ice measuring more than a cubic kilometer by scientists at the IceCube Neutrino Observatory.

This finding was made by a team of researchers from the University of Maryland led by Professor Gregory Sullivan.

The study of these cosmic neutrinos can lead to insights into the nature of these astrophysical phenomena that take place millions or even billions of light years away from Earth.

The UMD Physics Associate Professor Kara Hoffman states that these cosmic neutrinos are the basic building blocks of the universe. Every second there are billions of neutrinos that pass through unnoticed. The high energy particles that remain unaffected by the magnetic field and have a constant speed and direction either originate from the Sun or in the atmosphere of the Earth. But the astrophysical neutrinos originate from the outer world.

Even though they have been detected, their origin and the reason they occur continues to remain a deep unsolved mystery. But they speculate that gamma rays, black holes and active galactic nuclei could be a major source of these neutrinos.  It took the scientists over 50 years to come up with a high energy neutrino detector like the IceCube.

IceCube, that is operated by more than 250 physicists and engineers, was basically designed to measure the rate of the high energy neuirtinos and also track the origin of these neutrinos

Neutrinos are detected through tiny flashes of blue light termed Cherenkov light. This light is seen when the high energy particle comes in contact with ice.  Since they travel in straight line, they give clues to the place they originated from in the galaxy.

"IceCube is a wonderful and unique astrophysical telescope -- it is deployed deep in the Antarctic ice but looks over the entire Universe, detecting neutrinos coming through the Earth from the northern skies, as well as from around the southern skies," said Vladimir Papitashvili of the National Science Foundation (NSF) Division of Polar Programs.

Prior to this, in 2012 the IceCube had noticed two high energy events of above 1 petaelectronvolt (PeV), which were named as Bert and Ernie, and this marked the first record of astrophysical neutrinos by the terrestrial detector. They then shuffled through data hunting for more high energy neutrino events and they discovered 26 more, all at levels of 30 teraelectronovolts (TeV).

The findings were documented in the journal Science.