Tracing the source of cosmic rays to a blazar near Orion

"Where exactly in the active galaxy, neutrinos are produced will be a topic of debate," he added in an email. "It's clear that the supermassive black hole provides the power of the accelerator," he said, but how is a mystery.

The discovery is announced in a series of articles by an international body of physicists and astronomers in Science and the Astrophysical Journal, and in a sponsored press conference by the National Science Foundation, which funds the Neutrinos Ice Observatory of Amundsen. "I think that's the real thing," said John Learned, a neutrino expert at the University of Hawaii who is not part of IceCube, in an email, "the real beginning of astronomy of high-energy neutrinos We have dreamed for several decades. "Now, he added," we will begin to see in the guts of the most energetic objects in the universe .

Neutrinos are among the most abundant particles in the universe. – much more numerous than the protons and electrons of which we are composed. They have no electric charge and therefore a mass so low that it has not yet been accurately measured. They interact with other matters only by gravity and the so-called weak nuclear force and thus circulate through us, the Earth and even kilometers of lead like ghosts.

Yet, in theory, they are everywhere. Produced by radioactive decays of other particles, they flood us with nuclear reactions to the sun, distant supernova explosions and even the Big Bang. The big previous moment of neutrino astronomy occurred in 1987, when 25 neutrinos were recorded in three detectors on Earth coinciding with a supernova explosion in the Great Cloud of Magellan, a neighboring galaxy.

The attractiveness of neutrinos for astronomy is possible to trace them back to their origins. Not only do they fly long distances and other impenetrable places like the heart of the stars at the speed of light, but they are not affected by the interstellar and intergalactic magnetic fields and other influences that blur the paths of others. . types of cosmic particles, such as protons and electrons. Neutrinos go straight into the universe as Einsteinian gravity allows.

IceCube, an international observatory led by 300 scientists from 12 countries, includes more than 5,000 sensitive photomultiplier tubes integrated into a grid encompassing one cubic kilometer of ice at the South Pole. . When a neutrino strikes very, very, very, very, very rarely an atomic nucleus in the ice, it produces a cone of blue light called Cerenkov radiation that propagates through the ice and is captured by photomultipliers.