Strange signals that have been detected from Antarctic ice seem to defy laws of physics. Scientists are looking for an answer

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Scientists try to resolve a decade -long mystery by determining the identity of different signals that have been detected from under ice in Antarctica.

The strange radio waves emerged during a search for another unusual phenomenon: cosmic particles with high energy known as neutrinos. Arriving on earth from the distant corners of the cosmos, neutrinos are often called “spooky” because they are extremely volatile or vapor and can go through any form of matter without changing.

In the past decade, researchers have carried out several experiments with the help of huge expansions of water and ice that have been designed to look for neutrinos, which can shed light on mysterious cosmic rays, the most energetic particles in the universe. One of these projects was NASA’s Antarctic impulsive transient antenna, or Anita, experiment, who flew balloons that wore instruments over Antarctica between 2006 and 2016.

During this yacht, Anita picked up abnormal radio waves that did not seem to be neutrinos.

The signals came from under the horizon, which suggests that they had gone thousands of kilometers of rock before reaching the detector. But the radio waves should have been absorbed by the rock. The Anita team believed that these different signals could not be explained by the current understanding of particle physics.

Follow -up observations and analyzes with other instruments, including a recently performed by the Pierre Auger Observatory in Argentina, have not been able to find the same signals. The results of the Pierre Auger cooperation were published in March in the Physical Review Letters magazine.

The origin of the abnormal signals remains unclear, said Co -author Stephanie Wissel, formal professor of physics, astronomy and astrophysics at Pennsylvania State University.

“Our new study indicates that such (signals) were not seen by an experiment … like the Pierre Auger Observatory,” said Wissel. “So it does not indicate that there is new physics, but rather more information to add to the story.”

Larger, more sensitive detectors may be able to solve the mystery, or ultimately prove whether the abnormal signals were a fluke, while they continue the search for enigmatic neutrinos and their sources, scientists say.

The search for neutrinos

By detecting neutrinos on earth, researchers can trace them back to their sources, which, according to scientists, are primarily cosmic rays that touch the atmosphere of our planet.

The most energetic particles in the universe, cosmic rays mainly consist of protons or atomic cores, and they are released by the universe, because whatever she produces, such a powerful particle accelerator is that it is the possibilities of the great Hadron Collider dwarf. Neutrinos can help astronomers better understand cosmic rays and what launches them in the cosmos.

But neutrinos are hard to find because they have almost no mass and can go through the most extreme environments, such as stars and entire galaxies, unchanged. However, they interact with water and ice.

Anita is designed to look for the highest energy -neutinos in the universe, with higher energies than is still detected, said Justin Vandenbroucke, a physician’s senior lecturer at the University of Wisconsin, Madison. The radio antennas of the experiment is looking for a short pulse of radio waves produced when a neutrino collides with an atom in the Antarctic ice, which leads to a shower of lower energy particles, he said.

During his flights, Anita found high energy fountains of particles that came from the ice, a kind of upside down shower of cosmic rays. The detector is also sensitive to ultra -high energy -kosmic rays that rain on earth and create a radio burst that works as a flashlight beam of radio waves.

When Anita looks at a cosmic beam, the flashlight beam is really an eruption of radio waves a billionth of a second that can be mapped as a wave to show how it reflects from the ice.

An anomaly in the data

Twice in their data from Anita flights, the original team of the experiment saw signals that came through the ice in a much sharper corner than ever predicted by models, making it impossible to trace the signals on their original sources.

“The radio waves that we detected almost ten years ago were on real steep corners, such as 30 degrees under the ice surface,” said Wissel.

Neutrinos can travel through a lot of matter, but not completely through the earth, said Vandenbroucke.

“They are expected to come from something under the horizon, where there is not much soil to absorb,” he wrote in an e -mail. “The anomal events of Anita are intriguing because they seem to come from far below the horizon, so the neutrinos should travel through a large part of the earth. This is not possible according to the standard model of particle physics.”

The Pierre Auger cooperation, which includes hundreds of scientists around the world, analyzed more than a decade of data to try to understand the abnormal signals that have been detected by Anita.

The team also used their observatory to try to find the same signals. The Auger Observatory is a hybrid detector that uses two methods to find and study cosmic rays. One method is based on finding high energy particles while interaging with water in tanks on the earth’s surface, and the other follows potential interactions with ultraviolet light high in the atmosphere of our planet.

“The Auger Observatory uses a very different technique to observe ultra -high energy -Kosmic ray of air dones, using the secondary glow of charged particles while crossing the atmosphere to determine the direction of the Kosmic beam that it was initiated,” said Peter Gorhai, a professor in a professor. “By using computer simulations of what such a shower of particles would look like if it had behaved like the anomal events of Anita, they can generate a kind of template for similar events and then find their data to see if something like that appears.”

Gorham, who was not involved in the new research, designed the Anita experiment and conducted other research to understand more about the abnormal signals.

While the Auger Observatory was designed to measure down-to-down particle shower produced in the atmosphere produced by ultrahigh-energy cosmic rays, the team has redesigned their data analysis to search for air showers upwards, Vandenbroucke said. Vandenbroucke did not work on the new study, but he assessed it prior to the publication.

“Auger has a huge gathering area for such events, larger than Anita,” he said. “If the anomal events of Anita are produced by every particle that travels through the earth and then producing showering upwards, Auger should have detected a lot of them, and it didn’t.”

A separate follow-up examination using the ICECUBE experiment, which has embedded sensors deep into the Antarctic ice, also searched for the abnormal signals.

“Because Icecube is very sensitive, if the anomal events of Anita were neutrinos, we would have detected them,” wrote Vandenbroucke, who served as Colead of the Neutrino Sources Working Group between 2019 and 2022.

“It is an interesting problem because we still have no explanation for what those deviations are, but what we do know is that they probably don’t represent neutrinos,” said Wissel.

Strangely enough, a different kind of neutrino, called a Tau -Neutino, is a hypothesis that some scientists have the cause of the abnormal signals.

Tau -neutrinos can regenerate. When they fall at high energies, they produce another Tau -Neutino, as well as a particle called a Tau Lepton – similar to an electron, but much heavier.

But what makes the Tau -Neutino scenario very unlikely is the steepness of the corner connected to the signal, said Wissel.

“You expect all these Tau -Neutinos to be very, very close to the horizon, like perhaps one to five degrees under the horizon,” said Wissel. “These are 30 degrees under the horizon. There is just too much material. They would really lose a lot of energy and not be detectable.”

The future of detection

At the end of the day, Gorham and the other scientists have no idea what the origin of the abnormal Anita events are. So far, no interpretations correspond to the signals, which scientists withdraw to resolve the mystery. However, the answer can be in sight.

Wissel also works on a new detector, the load for ultra -high energy observations or Pueo, which will fly over Antarctica for a month that starts in December. Bigger and 10 times more sensitive than Anita, Pueo could reveal more information about what causes the abnormal signals that have been detected by Anita, said Wissel.

“At the moment it is one of these long -standing mysteries,” said Wissel. “I am excited that when we fly Pueo, we have better sensitivity. In principle, we must be able to better understand these deviations that will go a long way to understand our backgrounds and ultimately detect neutrinos in the future.”

Gorham said that Pueo, an acronym that refers to the Hawaiian Owl, should have the sensitivity to record many abnormal signals and to help scientists find an answer.

“Sometimes you just have to go back to the drawing table and really find out what these things are,” said Wissel. “The most likely scenario is that it is an everyday physics that can be explained, but we are beating a bit on all doors to try to find out what they are.”

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