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By Dennis Overbye
It was the smallest bullet you can imagine, a subatomic particle that weighs a little more than a thought. A supermassive black hole had it fired from a gravitational gun.
On September 22, 2017, a particle known as the neutrino sprang from the sky and crossed the Antarctic ice at almost the speed of light, triggering a cascade of alarms in a series of detectors called IceCube.
Within seconds, IceCube alerted an army of astronomical satellites, including the Fermi Gamma-Ray Space Telescope. This spacecraft found the origin of the neutrino in a dark spot in the sky, a distant galaxy called TXS 0506 + 056, right next to the left shoulder of the Orion constellation, which had a burst of X-rays and high gamma rays. intensity.
Astronomers said the discovery would provide long-sought clues to one of the most enduring mysteries of physics and the cosmos. Where does the rain of high-energy space particles known as cosmic rays come from?
The main suspects have long been quasars. These are gigantic black holes in the center of galaxies, where matter and energy burst violently like a toothpaste at the top and bottom of a rotating material wire.
![Nail Khairnasov, the chief technological engineer of the gallium germanium telescope, at the Baksan Neutrino observatory in Neytrino, Russia, April 11, 2018 .. (Maxim Babenko / The New York Times) [19659008] Nail Khairnasov, the chief technological engineer of the gallium-germanium telescope, at the Baksan Neutrino observatory in Neytrino, Russia, on April 11, 2018. (Maxim Babenko / The New York Times) </p>
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<p> Now you know at least one in which this seems to be the case. TXS 0506 + 056 is a type of quasar known as the blazar, in which our perspective of the Earth allows us to see the length of the collimated gust – directly through the canyon. The term blazar comes in part from BL Lacertae, a star-like object that turned out to be the first of these objects to be recognized </p>
<p> "We found the first source of cosmic rays," said Francis Halzen in an interview. the University of Wisconsin, the Madison Campus, and the director of IceCube. </p>
<p> "The exact location in the active galaxy where neutrinos are produced will be a topic of debate," he added. "It is clear that the huge black hole provides the power of acceleration," he said, but the way he does it remains a mystery. </p>
<p> The discovery was announced in a series of articles published by an international group of physicists and astronomers. Science and The Astrophysical Journal </p>
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Musabi Boliev, who directs the underground scintillation telescope at the Baksan Neutrinos Observatory. (Maxim Babenko / The New York Times)
Neutrinos are among the most abundant particles in the universe because they far surpass the protons and electrons of which we are composed. They have no electrical charge and have so little mass that has not yet been accurately measured. They interact with other materials only by gravity and the so-called weak nuclear force, and so they flow through us from the Earth and even through miles of lead like ghosts. "We found the first source of cosmic rays"
However, in theory they are everywhere. Produced from the radioactive decay of other particles, they flood us with nuclear reactions in the Sun, distant supernova explosions and even the Big Bang.
The attraction of neutrinos for astronomy is that it is possible to trace their origin. Not only do they travel long distances at the speed of light and at impenetrable locations, such as star cores, but without any electrical charge, they are unaffected by interstellar or intergalactic magnetic fields or d & # 39; Other influences they modify the path of other types of cosmic particles, such as protons and electrons. Neutrinos penetrate the universe as directly as the gravity of Einstein allows.
Valery Gorbachev, principal investigator, installs meters with radioactive isotopes. (Maxim Babenko / The New York Times)
IceCube, an international observatory led by three hundred scientists from twelve countries, is made up of more than five thousand sensitive photomultiplier tubes integrated into a network covering one cubic kilometer of ice at the South Pole. . When a neutrino collides extraordinarily with an atomic nucleus in the ice, it produces a cone of blue light called Cerenkov radiation, which expands through the ice and is absorbed by photomultipliers.
IceCube was built to find the origin of cosmic rays, said Halzen, and the observatory has recorded neutrinos since it began working in 2011, but until the end of the day. At present, he has not been able to determine the origin of any of them. One reason, he said, was that the scientists had assumed that the origin would be close, maybe even in our galaxy, the Milky Way.
One of the carriers of the staff of the observatory. (Maxim Babenko / The New York Times)
However, TXS 0506 + 056 is very far, about 4 billion light-years away. It's one of the brightest objects in the universe, says Halzen.
The neutrino that triggered the alarm in 2017 had an energy of about 300 billion electronvolts, nearly fifty times the energy produced by the Large Hadron Collider at CERN . the largest particle accelerator on Earth.
It can be said that the origin is the Large Hadron Collider in the sky. It is believed that it is a kind of huge black hole that runs through the center of this distant galaxy. For now, the detailed operation of this cosmic accelerator is still a mystery.
Dennis Overbye se joined the New York Times in 1998 and was reporter from 2001. Ha written two books : "Solitary Hearts of the Cosmos, Scientific Research of the Secret of the Universe" and "Einstein in Love, a novel scientist ".
© 2018 New York Times News Service
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