Last updated July 20, 2018 at 9:28 am
The cool ice of Antarctica is now one of the hottest places on Earth for particle physics.
A cubic kilometre of Antarctica’s ice sheet has lit up as a ghost-like particle slammed into at nearly the speed of light.
The observations made by the IceCube Neutrino Observatory at the Amundsen-Scott South Pole Station, are the first evidence of a source of high-energy particles called neutrinos: an energetic galaxy about four billion light years from Earth.
Two Science papers, which explore the detection of the neutrinos, and the coincident astronomy observations, made clear that black holes are the source of ultra-high energy cosmic rays.
The search has been an elusive one.
Trillions of near-massless neutrinos, produced in high energy cosmic events, stream through your body each and every second.
Yet with no charge and only the tiniest of cross-sections they will never impact your atoms nor those of the Earth below you.
In fact, you would need lead shielding light years in thickness to stop half of these neutrinos. But if astronomers can somehow detect them then they would reveal their source as they aren’t deflected or impeded by galaxies, stars or intergalactic magnetic fields on their journey to Earth.
While an individual neutrino will likely never interact in the entire history of the universe, the sheer number of these particles ensures that sooner or later one will collide with an atom, the only issue is building a large enough detector.
The IceCube experiment sunk 5,160 digital optical modules – basically sensitive light detectors – strung like Christmas lights into 86 melted holes in Antarctic ice spaced over a cubic kilometre.
The ice is nearly perfectly clear allowing particle collisions to be seen by multiple digital modules and reveal their path, allowing a CSI-like approach to figure out where they came from.
In this case a neutrino collides with the oxygen atom of water, creates a shower of secondary particles which then move faster that light can in the ice, causing the light equivalent of a sonic boom which we see as a pale blue glow of Cherenkov Radiation.
The neutrinos arriving coincided with high energy gamma-rays from an outburst of a blazar, TXS 0506+056, nearly four billion light years from Earth.
Blazars are galaxies that host massive spinning black holes that fire radiation and particles along twin jets, which happen to be directly pointed towards us.
A Blazar is an actively feeding massive spinning blackhole which sends twin jets of light and particles at relativistic speeds along which the Earth happens to be directly aligned. Credit: IceCube / NASA
This is the first identified neutrino source in decades and ushers in the era of astro-particle physics, where information of extreme events from their light can now be combined with particles reaching Earth.
These feeding blackholes, or exploding stars, can accelerate particles to millions of times more energetic than anything we can create on Earth.
