The source of a mysterious radio signal originating from the Antarctic ice layer continues to puzzle scientists.

The signal, detected as radio waves, was initially captured by the Antarctic Impulsive Transient Antenna (ANITA) in 2006 and 2014.Unusually, the signal appeared to originate from beneath the ice, rather then from outer space.

“The waves are very steep, around 30 degrees below the surface of the ice,” stated Astrophysicist Stephanie Wissel from Penn State University, as quoted by Science Alert on Wednesday (6/18/2025). she added, “And until now, we don’t have a definite clarification, but most likely it is indeed not Neutrino.”

Even though ANITA was designed to detect waves from cosmic rays entering the atmosphere from space, this particular signal seemed to come from the opposite direction. this has led to speculation about the potential existence of previously unknown particles.

The research team attempted to correlate the data with observations from other cosmic observatories, including the Pierre Auger Observatory in Argentina. after examining data from 2004 to 2018, they found no similar signals. This strengthened the belief that the signal was not caused by neutrinos. however, the true source of the signal remains a mystery.

ANITA has been retired since its last flight in 2016. Its replacement,the Payload for Ultrahigh Energy Observations (PUEO),is scheduled to begin operations in Antarctica soon.

“I think there may be a certain radio wave propagation effect near the ice or horizon that we do not understand,” WISSEL said.

“But we have explored various possibilities and have not found the answer,” he continued.

He noted that the mystery remains unsolved. however,scientists are optimistic because PUEO’s improved sensitivity may provide new insights.

“Hopefully, we can detect more anomalies, or even neutrino that can be much more interesting,” he concluded.