Strange Radio Signals Detected Emanating From Deep Under Antarctic Ice

Nearly 20 years in the past, an experiment floating top above Antarctica stuck a peculiar sign.

Designed to seize the radio spurts of cosmic rays falling from above, in 2006 the Antarctic Impulsive Transient Antenna (ANITA) recorded a brief pulse of radio waves from underneath – an tournament that seemed like an upside-down bathe of cosmic rays, now not bouncing off the skin, however emanating from underneath the ice sheet.

The balloon-borne suite of tools recorded a equivalent tournament in 2014, and scientists had been scratching their heads ever since. No rationalization fairly suits, suggesting that the wrongdoer is usually a particle unknown to science.

“The radio waves that we detected were at really steep angles, like 30 degrees below the surface of the ice,” explains astrophysicist Stephanie Wissel of Pennsylvania State University.

“It’s an interesting problem because we still don’t actually have an explanation for what those anomalies are, but what we do know is that they’re most likely not representing neutrinos.”

The sign itself, an overly temporary pulse of radio waves, is similar to what we would possibly see from an elusive tau neutrino, however there are a number of causes neutrino interpretation of the sign is tricky to unravel.

Scientists idea that the sort of neutrino might come from a supernova that then tunnels its approach all over Earth and springs out the opposite aspect. However, best the 2014 detection coincided with a supernova which may be accountable – no such tournament was once discovered for the 2006 detection.

In addition, the steep perspective of the detection implies that the neutrino would have needed to tunnel via rock sooner than rising from the ice. Neutrinos flow via topic always; it is what they do, and why we name them ‘ghost debris‘. That’s now not the issue.

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“You have a thousand million neutrinos passing via your thumbnail at any second, however neutrinos do not in point of fact engage,” Wissel says. “So, that is the double-edged sword downside. If we stumble on them, it manner they’ve traveled all this manner with out interacting with anything. We may well be detecting a neutrino coming from the threshold of the observable Universe.”

To help solve the mystery of the upward-propagating radio pulses, a large international team of researchers made a careful study of data collected by the Pierre Auger Observatory in Argentina, designed to study high-energy cosmic rays. They conducted simulations to determine how the ANITA events might appear in the Pierre Auger Observatory data, and combed through the observations from 2004 to 2018, looking for similar signals.

They discovered not anything that explains the ANITA detections. However, in science, discovering not anything regularly manner discovering one thing – even though that one thing is a narrower set of choices.

In this case, it means that the scientists could confidently rule out neutrinos as an explanation for the signals. However, that doesn’t automatically mean we’re looking at a new particle, either. We’re going to need further observations, and hopefully new detections, to determine what it is that ANITA saw coming from the Antarctic ice.

ANITA is retired; its last flight took place in 2016. A new Antarctic balloon experiment called the Payload for Ultrahigh Energy Observations (PUEO), the successor to ANITA, is because of begin operations quickly.

“My bet is that some attention-grabbing radio propagation impact happens close to ice and in addition close to the horizon that I do not absolutely perceive, however we without a doubt explored a number of of the ones, and we’ve not been ready to seek out any of the ones but both,” Wissel says.

“So, presently, it is such a long-standing mysteries, and I’m excited that after we fly PUEO, we’re going to have higher sensitivity. In concept, we will have to select up extra anomalies, and possibly we’re going to in reality perceive what they’re. We additionally would possibly stumble on neutrinos, which might in many ways be much more thrilling.”

The newest effects had been revealed in Physical Review Letters.