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Tech & Science
Scientists recorded 13 unusual radio signals under Antarctic ice, potentially confirming a 1962 theory about cosmic particles.
Deep beneath the Antarctic ice, scientists have detected 13 mysterious radio signals that may confirm a decades-old prediction about how cosmic particles behave. The signals, recorded over 208 days in 2019, appear to originate from below the ice surface, according to a study published in the journal Physical Review Letters.
The research team, part of the ARA Radio Array project—a collaboration of researchers and institutions specializing in particle physics and astrophysics—announced that these signals could represent the first experimental evidence of a phenomenon known as "Askaryan radiation." Soviet physicist Gurgen Askaryan first predicted this effect in 1962, describing it as a faint radio signal produced when a high-energy cosmic particle passes through a dense material, leaving a trail of charged particles in its wake. While the phenomenon had been demonstrated in laboratory conditions, it had never been observed experimentally before.
Using advanced simulation models, the team analyzed the signals' characteristics, including their arrival direction, frequency, waveform, and electric field orientation. The results showed that all these properties closely matched theoretical predictions for Askaryan radiation generated by cosmic rays interacting with ice. The researchers calculated that the probability of these signals being caused by random interference or terrestrial sources is less than one in 3.5 million, a statistical significance of 5.1 sigma—the threshold typically used in physics to confirm a discovery.
The scientists believe the signals were produced by dense nuclei from cosmic ray showers that penetrated the upper layers of the ice, triggering particle interactions that emitted short radio waves. This discovery marks a significant step toward the project's primary goal: detecting ultra-high-energy neutrinos, extremely rare cosmic particles capable of passing through matter almost entirely without interacting.
Scientists distinguish between neutrinos and cosmic rays based on the angle and depth of the signal within the ice. Cosmic rays typically affect only the surface layers, while neutrinos can penetrate deeper and produce signals from different angles. With expanded data expected to cover additional years of observation across all ARA Radio Array stations, the research team hopes to confirm more candidates for these rare particles, potentially opening a new window into understanding the most energetic and mysterious phenomena in the universe.
