Unknown radio waves that "defy physics" are emanating from deep beneath the Antarctic ice.

Antarctica has some of the world's clearest skies, which makes it the ideal location for eavesdropping on the universe. The Antarctic Impulsive Transient Antenna, or ANITA, is carried by a NASA balloon that hovers far above the continent. When ultra-energetic cosmic rays strike the atmosphere, radio murmurs are captured by the ANITA experiment.

The majority of those pops exhibit the precise behaviour predicted by physicists: after bouncing off the two-mile-thick ice sheet, the signals reverse polarity, creating a clear mirror image that indicates the particle originated from above.

However, a few pulses that are resistant to flipping have also been recorded by ANITA.

The inference is disturbing since a particle must plough straight through the planet, survive over 3,000 miles of rock, and then explode out of the ice on the far side to emit such upward-going radio waves. That method should be impossible for any known particle.

ANITA detects pulses that break the rules.

Rather than the mild slopes found in typical cosmic-ray echoes, those anomalous pulses emerged from roughly 30° below the horizon at startlingly sharp angles. The geometry by myself flags them as outliers, but the group tested that the pulses have been actual and now no longer an instrumental hiccup.

“The radio waves that we detected have been at virtually steep angles, like 30 degrees under the floor of the ice,” stated Stephanie Wissel, an accomplice professor of physics, astronomy, and astrophysics who combs the ANITA data for sudden patterns.

“It`s an exciting hassle due to the fact we nonetheless don`t have a reason for what the ones anomalies are, however what we do recognise is that they`re maximum likely now no longer representing neutrinos.”

Helping ANITA clear out cosmic chatter

Separating real particle signatures from noise takes painstaking effort. Researchers replay hundreds of hours of balloon information through laptop models that mimic the detector`s reaction to lightning, satellite tv for pc transmissions, or even the crackle of auroras.

By evaluating the one simulation with actual occasions, they could cull whatever lacks the hallmark form of a particle-induced shower.

The ANITA collaboration additionally leans on cross-assessments with ground networks, including IceCube and the Pierre Auger Observatory. If a pulse seems simplest within the balloon logs and nowhere else, it is going under the microscope.

The handful of peculiar upward occasions survived each clear out, out the scientists may want to devise, reinforcing the feeling that something unusual is in play.

Ghostly nature of neutrinos

The apparent culprits might be neutrinos, the universe`s maximum elusive messengers. These chargeless wisps rarely collide with matter, making them ideal probes of remote cataclysms, but fiendishly difficult to spot.

“You have one billion neutrinos passing through your thumbnail at any moment; however, neutrinos don`t interact virtually have interaction,” she stated.

“So, that is the double-edged sword hassle. If we come across them, it's apparent they've traveled all this way without interacting with whatever else. We will be detecting a neutrino coming from the brink of the observable universe.”

Listening from 25 miles up

“We use radio detectors to try and construct, virtually, big neutrino telescopes so that we can cross after a quite low predicted event rate,” Wissel explained.

ANITA tackles that undertaking with the aid of floating more or less 25 miles above the snow, a perch that expands every antenna`s footprint to masses of rectangular miles without planting a single pole within the ice.

“We have those radio antennas on a balloon that flies forty kilometers above the ice in Antarctica,” Wissel stated. “We factor our antennas down on the ice and search for neutrinos that have interaction within the ice, generating radio emissions that we can then detect with our detectors.”

Why does any of this matter?

When the group traced the bizarre indicators backward, the flight paths pointed through Earth`s interior, defying the same old version of particle physics. The list of common explanations was reduced when further searches in data from the IceCube and Auger neutrino detectors failed to find any parallel events.

We certainly investigated several things, but we haven't been able to locate any of them yet, Wissel added. "I think there is some interesting radio propagation effect that occurs near ice and also near the horizon that I don't fully understand," Wissel said.

I'm hoping PUEO can assist

The Payload for Ultrahigh Energy Observations, or PUEO, is the next balloon in the series and is scheduled to make its first Antarctic trip in December 2025. Compared to ANITA, its sensitivity will be at least five times higher thanks to its faster electronics and larger antennae.

"So, it's one of these old mysteries right now, and I'm excited that we'll have better sensitivity when we fly PUEO," Wissel said in closing. Theoretically, we ought to detect more irregularities, and perhaps we will even identify them. Additionally, we might find neutrinos, which would be much more fascinating in some respects.

What follows?

In other places, devices that are fixed to the seafloor, buried deep under ice, or orbiting on satellites are also achieving success. The rapid advancement of the field was highlighted in February 2025 when a detector located beneath the Pacific seafloor recorded the highest powerful neutrino yet seen.

Future missions should provide new insights into whether ANITA's oddities are caused by unusual particles or a peculiarity of radio transmission. We will all have to wait and wonder until then.