Everything you need to know about space ghosts!

Neutrinos are very, very low-mass particles that travel at speeds close to the speed of light. These ghost particles have two distinct features; First, they have no load and secondly, they have very, very little mass! In this regard, it is interesting to know that physicists believed for decades that neutrinos have no mass, but with the development of detectors, our knowledge about the characteristics of these particles has increased until today we can use these ghostly particles to reveal the secrets of the universe to us. !

What is a neutrino and what's so important about it?

Neutrinos are the most abundant subatomic particles in the universe, but they rarely interact with any kind of matter. It's interesting to know that we humans are bombarded by millions of tiny neutrinos every second, yet these strange particles pass right through us without us noticing. That's why Isaac Asimov called them "ghost particles"!

Naturally, this low rate of interaction due to the properties of the neutrino makes it very difficult to detect this particle, on the other hand, the lightness of these particles is a factor that can help the neutrino to travel unhindered (and therefore largely unchanged) in the effect collide with other particles to disperse. This means that neutrinos can provide astronomers and physicists with valuable clues about distant systems that, along with the existence of telescopes capable of detecting a wide range of electromagnetic waves and gravitational waves, can teach us more secrets of the universe.

Neutrinos help solve the mysteries of the universe!

Ever since the French physicist Pierre Auger proposed in 1939 that cosmic rays must carry incredible amounts of energy, scientists have wondered what What could produce these powerful clusters of energy in the Earth's atmosphere, they wondered. In this regard, one of the possible ways to identify such sources is to reverse-engineer the paths that high-energy cosmic neutrinos take on their way to Earth. These particles are created as a result of the collision of cosmic rays with matter or radiation, and after this collision they decompose into particles such as neutrinos and gamma rays!

Scientists of the Neutrino Detector Observatory "IceCube" after a decade The investigation and analysis of such neutrinos yielded evidence that the active galaxy Messier 77 is a strong candidate for emitting high-energy neutrinos. Considering this issue, astrophysicists hope to be one step closer to solving the mystery of the origin of high-energy cosmic rays by discovering this source! Ice Cube Neutrino Detector Observatory is a scientific and research observatory built in Antarctica. It is interesting to know that the detection system of this observatory has thousands of light-sensitive sensors scattered in a space of one cubic kilometer of ice. Icecube is the first neutrino detector to find the source of cosmic rays and is designed to search for neutrino sources in the electron-volt spectrum.

When a neutrino interacts with molecules in the clear ice of Antarctica , secondary particles are produced that leave behind a trail of blue light as they pass through the ice cube detector.

Why do they build neutrino observatories underground?

In the world of science, more They bury neutrino detectors deep in the earth; Because with this method, it becomes easier to detect these particles and they will be safe from interference with other particles from the universe. In the meantime, the Ice Cube Observatory is no exception to this rule, and arrays of optical sensors as large as basketball hoops are buried deep in the Antarctic ice! Interacting in the ice, the collision produces pregnant particles that emit ultraviolet and blue photons, which are picked up by detectors. So you're probably well aware that this particular observatory is in a good position to help physicists advance their knowledge of the origins of high-energy cosmic rays. Cosmic rays can include protons or clusters of neutrons. and normal-energy protons, while ultrahigh-energy cosmic rays are much more energetic than protons spinning at 99.99999991 percent of the speed of light in the circular tunnels of the Large Hadron Collider.

In general, it is necessary to know that cosmic rays only include atomic nuclei (such as a proton or a cluster of protons and neutrons); However, rare rays known as extremely high-energy cosmic rays They have energy the size of tennis balls coming at us with a professional serve. This class of cosmic rays are millions of times more energetic than the protons that spin at 99.9999991% of the speed of light in the circular tunnels of the Large Hadron Collider in Europe.

It is interesting to know that the most energetic cosmic ray ever discovered with Nicknamed the "Oh-My-God particle," it was discovered in 1991, traveling at about 99.9999999999999999999999999951 percent of the speed of light. This type of neutrino had an energy almost similar to the energy of a bowling ball that reaches the thrower's toes from the throw position.

The energy of this neutrino was almost the same as the energy of a bowling ball that reaches the player's toes from the throwing position.

The source of powerful cosmic rays

But where do such powerful cosmic rays come from? A strong possibility to answer this question is active galactic nuclei (AGNs), which are found at the center of some galaxies. In fact, the energy of this group of active nuclei comes from very massive black holes in the center of the galaxy or circulating black holes!

According to the large number of background neutrinos and other particles in the Earth's atmosphere, finding sources of energetic neutrinos in space is a task. It is not easy. In 2018, the Ice Cube Observatory detected a burst of neutrinos that appeared to come from a blazar (an active galactic nucleus capable of emitting particles at or near the speed of light). At the same time, scientists needed to find other and similar cosmic neutrino sources to reconcile these observations with existing neutrino models. In this regard, "Messier 77" is another candidate galaxy for the source of cosmic rays and energetic neutrinos.

"Messier 77" was discovered in 1780 by a French astronomer named Pierre Mechain. At the time, the astronomer listed this galaxy as a star cluster, but now we know that this object is nothing more than a spiral galaxy with barred arms (similar to the Milky Way) in the constellation Citus at a distance of about 46 It is not a million light years from the earth! It is interesting to know that earlier this year (2022), astronomers using the European Southern Observatory's Very Large Telescope Interferometer confirmed that "Messier 77" has a very massive black hole at its center, which is covered by thick gas and dust. p>

Discovery of sources of powerful cosmic rays

Finally, in 2020, using machine learning techniques and in collaboration with Ice Cube Observatory researchers, data collected between 2008 and 2018 were analyzed, and during this The study found that more than 79 background neutrinos, with a statistical significance of 4.2 sigma (reason enough to declare a discovery!) were emitted from 4 possible active galactic nucleus (AGN) candidates! It should be noted that along this path, these experiments have been repeated many times and the probability that they have reached this result by chance is less than 1 in 100,000.

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Source: ScienceNews