Animation of Neutrino courtesy of National Science Foundation via Reuters
A breakthrough in the study of ghostly particles called high-energy neutrinos that traverse space, zipping unimpeded through people, planets, and whole galaxies, is giving scientists an audacious new way to expand our understanding of the cosmos.
Researchers on Thursday (July 12) said they have for the first time located a deep-space source for these ubiquitous subatomic particles. They detected high-energy neutrinos in pristine ice deep below Antarctica’s surface, then traced their source back to a giant elliptical galaxy with a massive, rapidly spinning black hole at its core, called a blazar, located 3.7 billion light-years from Earth in the Orion constellation.
The key observations were made at the IceCube Neutrino Observatory at a U.S. scientific research station at the South Pole and then confirmed by land-based and orbiting telescopes.
Astronomers long have relied upon electromagnetic observations – studying light – but this approach has limitations because too many aspects of the universe are indecipherable using light alone.
The ability to use particles like high-energy neutrinos in astronomy enables a more robust examination, much as the confirmation of ripples in the fabric of space-time called gravitational waves, announced in 2016, opened another new frontier in astronomy. This emerging field is dubbed “multi-messenger astrophysics.”
The findings solve a mystery dating to 1912 over the source of subatomic particles like neutrinos and cosmic rays that dash through the cosmos. It appears they arise from some of the universe’s most violent locales.
High-energy neutrinos are produced by the same sources as cosmic rays, the highest-energy particles ever observed, but differ in a key respect — as charged particles, cosmic rays cannot be traced straight back to their source because strong magnetic fields in space alter their trajectory.
Neutrinos are electrically neutral, undisturbed by even the strongest magnetic field, and rarely interact with matter, earning the nickname “ghost particle.” The direction from which they arrive points directly back to their original source.
The IceCube neutrino detector involves 86 holes drilled 8,200 feet (2,500 meters) into the Antarctic ice. Some 5,160 light sensors register small flashes of light produced during rare instances when a neutrino collides with an atomic nucleus in the transparent ice. The key detection came on Sept. 22, 2017, with the neutrino ultimately traced back to the blazar.
Scientists then determined that other neutrinos earlier detected by IceCube originated from the same source.— Reuters