Neutrinos are subatomic particles very similar to electrons, but their mass is small, they have no electric charge, and interact with other matter very rarely. These particles are one of the most abundant in the Universe but are incredibly difficult to detect, some experts say.
About 100 billion neutrinos are in motion through every square centimeter of a human body, being created by the Big Bang and still generated by everything in the Universe.
One of the latest neutrino mystery started when a few such particles were detected by the ANtarctic Impulsive Transient Antenna (ANITA) on the continent of Antarctica. Unlike most neutrino detectors that are huge, sensitive arrays, ANITA is a radio instrument attached to a balloon, and it can only identify high-energy neutrinos when they burst in the Antarctic ice to generate a flare of radio light.
At the beginning of this year, ANITA discovered some baffling signals that seemed to be produced by extremely high-energy neutrinos, with such a high amount of energy that they appeared to defy the standard model of particle physics.
All the Way to Supermassive Black Holes
A while ago, a group of scientists examined one possible source of high-energy neutrinos: the supermassive black holes of quasars. Supermassive black holes are gravitational powerhouses, compressing the hot gas in their vicinity using gravity and electromagnetic fields. These gigantic cosmic objects are capable of discharging massive amounts of energy, including high-energy neutrinos.
The researchers compared four dozen neutrino findings in the Antarctica with radio data from the Russian RATAN-600 radio telescope and discovered that the neutrinos were detected by the instruments when a quasar encountered a radio flare.
One of the most logical explanations is that when quasars are active, gamma-ray bursts are generated within the radio flare. The gamma rays then collide with the atoms in the surroundings, creating a burst of neutrinos, and because neutrinos travel at almost the speed of light, they arrive on Earth at the same time as the radio burst.
Still, this study only focuses on one part of the high-energy neutrino enigma. Researchers know, however, one method these particles use to take form, but the origins of the most energetic neutrinos ever found is still not known.