They first detected it in 2016.
NASA deployed antennas looking for extremely high-energy particles called neutrinos. These particles are constantly raining down from the cosmos. And if you can grab just one and study it, they're a gold mine of information.
Why are they so valuable? Neutrinos are generated by the most extreme events in space: gamma ray bursts, collapsing stars, merging neutron stars, and black holes. They travel across interstellar distances with all their raw information in tact, giving scientists the incredible chance to study actual pieces of cosmic events that happened millions of lightyears away. Add to that, they travel in a straight path, so scientists can work out exactly where they originated. And that could literally be from the edge of the known universe.
It makes sense NASA would go all out to capture one. But there's one small problem. They are nearly impossible to capture.
High energy neutrinos pass through matter without stopping, including people and telescopes. In fact, billions of neutrinos are passing through you right now. A traditional telescope can use a mirror to reflect light from space and analyze it. But high-energy neutrinos just pass right through the mirror. And the observatory. And the ground beneath it. Ultimately they react with atoms in the Earth and get absorbed.
So how does NASA use antennas to detect them?
Well, they think big. And they count on getting lucky.
Once in a great while, a neutrino will hit an atom in a substance like ice and cause a tiny reaction. The reaction causes a shower of particles that can be "heard" as radio waves, almost like a pop of static.
NASA's plan was to float radio antennas in balloons 120,000 feet in the air to detect these "pops", or radio pulses from particle showers. For the reflecting material they went big: they floated the balloons over Antarctica, which provided millions of square miles of super-clear ice. They turned the bottom of the Earth into an enormous neutrino lab. The idea was, with billions of neutrinos flying down from space all the time, they'd "hear" a reaction from at least one.
The project was called ANITA (Antarctic Impulsive Transient Antenna). If it sounds crazy, that's because it was. It didn't work at all.
They attempted four times: ANITA I in 2006, ANITA II in 2008, then again in 2014 and 2016. With each month-long mission, the flights of the ANITA balloons detected no ultra-high-energy neutrinos from space. There are no plans to try again -- not in this same way (the hunt for neutrinos goes on).
But they did hear something.
On two of the four missions, the antennas picked up mysterious radio pulses. Only they didn't originate from space. They came from the other direction -- from beneath the ice of Antarctica.
The anomalous events looked like the expected radio pulses from neutrinos. But their trajectory didn't make sense. If they'd been from a neutrino, it would mean they passed through the Earth, interacted with the ice near the surface, and burst out of the ice as a radio signal picked up by ANITA. They would have traveled through the entire planet without being absorbed. This defies what we understand about neutrinos, and, well, all physics. The Earth should stop them.
A recent study attempted to resolve the mystery. Researchers at the Pierre Auger Observatory in Argentina analyzed 15 years of cosmic data to try to make sense of the mystery signals. They ran computer simulations to figure out if these seemingly impossible neutrino paths ever happened. They only found one possible event, which is about what they expected just from random error or misidentified normal cosmic rays.
The paper was published in March of 2025. Their conclusion? The ANITA events were not caused by these kinds of upward-going showers. These radio pulses weren't from cosmic neutrinos at all.
So what was it under Antartica producing electromagnetic radio bursts in short, nanosecond pulses?
Turns out, the Earth's most unexplored continent may be hiding something.
In 2016, around the time ANITA reported the anomalous signals, satellite images circulated showing giant pyramids rising from the miles of ice. These were dismissed as simply mountains, but the perfectly square 1.3 mile base was enough to go viral among those open to other explanations.
In 2019, Investigative journalist Linda Moulton Howe produced an entire documentary describing how alien bases are hidden under Antartica, safe from human intervention because of the extreme environment.
Obviously, these are far-fetched ideas. Still, we're left with a basic fact: something under Antartica is sending signals.