A team of international scientists has finally detected the origin of the ghostly high-energy cosmic neutrinos that traveled billions of light-years through the universe.
Neutrinos were born around 15 billions of years ago, right after the birth of the universe. They can travel in a straight line, passing through different galaxies, planets, stars, and other cosmic bodies, until eventually arriving on Earth unscathed — such was the case of the neutrino found in the South Pole on Sept. 22, 2017. Neutrinos can also be a by-product of the charged particles in cosmic rays that was first discovered in 1912 by physicist Victor Hess.
For more than a century, experts were baffled about the exact place in the universe where these neutrinos are coming from.
Now, through the neutrino discovered in Antarctica, experts finally have the answer: the blazar, a giant elliptical galaxy with a massive and rapidly spinning black hole. Blazar is an active galaxy with twin jets of light that shoot laser beams from the poles on the axis of the black hole's rotation.
Ghostly Neutrino In Antarctica
The IceCube Neutrino Observatory detected the first signs of high-energy neutrinos five years ago. At first, they appeared to be shooting from random directions across the sky — until a single neutrino was recorded by the IceCube telescopes deployed at the South Pole.
For the study, published in the journal Science on July 13, the team headed by the University of Wisconsin drilled 86 holes into the Antarctic ice, each at least 2,500 meters deep. They then lowered 5,160 light sensors that registered the tiny flashes of light produced by the neutrino as it reacted with the transparent ice.
The neutrino was found to be of highly electrically charged. To be exact, it has around 300 tera-electronvolts or more than 40 times stronger than the protons being produced by the Large Hadron Collider, which is already the world's largest particle accelerator. Just within minutes of recording the activity, the IceCube alerted different astronomical laboratories across the world.
Soon, NASA's orbiting Fermi Gamma-ray Space Telescope and the Major Atmospheric Gamma Imaging Cherenkov Telescope in the Canary Islands scanned the Antarctic region for all forms of cosmic rays, visible light, and radio waves signal in the Antarctic region.
The worldwide concerted effort detected that the neutrino was coming from a galaxy nearly 4 billion light-years away — the blazar — that was located in the constellation of Orion. It was also found that its rapidly spinning black hole served as the galaxy's own natural particle accelerator.
The discovery of blazar has since been determined as a breakthrough in the field of astronomy.
"This is a milestone for the budding field of neutrino astronomy. We are opening a new window into the high-energy universe," said Marek Kowalski, the head of Neutrino Astronomy in a research center at the Humboldt University in Berlin.
A Dozen More Ghost Particles
In a separate study, also published in the journal Science on July 13, the scientists detailed other neutrinos detected when NASA's Fermi Gamma-ray Telescope in the Canary Islands responded to IceCube's alarms.
Indeed, the instruments were able to trace a significant increase of activities coming from the newly discovered blazar. Moreover, a review of previous IceCube data revealed that more neutrinos detected from the previous years were coming from the same blazar. The team was able to determine a distinct surplus of more than a dozen of the ghostly neutrino particles arriving from the blazar between September 2014 and March 2015.
Ultimately, the team concluded that there are other blazars out in the space, and these active galaxies are the main sources of high-energy cosmic neutrinos.