Ice Cube/NSF
Since the French physicist Pierre Auger suggested in 1939 He cosmic rays Scientists were puzzled by what could produce these powerful clumps of protons and neutrons that rain down on Earth’s atmosphere, as it must carry an incredible amount of energy. One possible way to identify such sources is to trace back the paths high-energy cosmic neutrinos took on their way to Earth, as they are created by cosmic rays colliding with matter or radiation, producing particles that then decay into neutrinos and gamma rays.
with scientists ice cube Neutrino observatories at the South Pole have now analyzed ten years of such neutrino detections and found that an active galaxy M77 (aka Squid Galaxy) is a strong candidate for such a high-energy neutrino emitter, according to a study. new paper It was published in the journal Science. It brings astrophysicists one step closer to solving the mystery of the origin of high-energy cosmic rays.
“This observation marks the dawn of the ability to truly do neutrino astronomy,” said Janet Conrad, IceCube member of MIT. APS Physics told. “We’ve struggled for a long time to see potential cosmic neutrino sources of very high importance, and now we’ve seen one. We’ve overcome a hurdle.”
Aspect we have previously reported, neutrinos travel close to the speed of light. John Updike’s 1959 poem, “cosmic bile,” pays homage to two of the most defining characteristics of neutrinos: They have no charge, and for decades physicists have believed they have no mass (they actually have a tiny bit of mass). Neutrinos are the most abundant subatomic particle in the universe, but they rarely interact with any matter. We are constantly bombarded with tiny particles, yet they pass through us unwittingly. That’s why Isaac Asimov called them “ghost particles.”
Nicolle R. Fuller, IceCube/NSF
This low interaction rate makes neutrinos extremely difficult to detecthowever, because they are so light, they can escape unhindered (and thus largely unchanged) through collisions with other matter particles. This means they can provide astronomers with valuable clues about distant systems and augment it further with what can be learned with telescopes across the electromagnetic spectrum, as well as gravitational waves. Together, these different sources of information have been termed “multi-message” astronomy.
Most neutrino hunters bury their experiments deep in the ground to eliminate noisy interference from other sources. In the IceCube example, the collaboration includes basketball-sized arrays of optical sensors embedded deep in the Antarctic ice. In rare cases, when a passing neutrino interacts with the nucleus of an atom in ice, the collision produces charged particles that emit UV and blue photons. These are picked up by sensors.
Therefore, IceCube is in a good position to help scientists improve their knowledge of the origin of high-energy cosmic rays. Convincingly as Natalie Wolchover Announced on Quanta In 2021:
A cosmic ray is just an atomic nucleus – a proton or a cluster of protons and neutrons. Yet rare ones known as “ultra-high-energy” cosmic rays have as much energy as professionally served tennis balls. They are millions of times more energetic than protons blasting around the circular tunnel of the Large Hadron Collider in Europe at 99.9999991% of the speed of light. In fact, the most energetic cosmic ray ever detected, nicknamed the “Oh-My-God particle,” hit the sky in 1991 and hit 99.9999999999999999999951 percent of the speed of light, giving it roughly the energy of a bowling ball. shoulder height to toe.
But where do such powerful cosmic rays come from? a strong possibility active galactic nuclei (AGNs) are found at the center of some galaxies. Their energies come from supermassive black holes at the center of the galaxy and/or from the black hole’s rotation.
