Strange signals detected from Antarctic ice seem to defy laws of physics. Scientists are searching for an answer Ashley Strickland By Ashley Strickland, CNN 7 min read Updated 8:49 PM EDT, Fri June 20, 2025 84 comments NASA’s Antarctic Impulsive Transient Antenna, or ANITA, experiment flew over stretches of Antarctic ice via a balloon. NASA’s Antarctic Impulsive Transient Antenna, or ANITA, experiment flew over stretches of Antarctic ice via a balloon. Stephanie Wissel/Penn State Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. CNN — Scientists are trying to solve a decade-long mystery by determining the identity of anomalous signals detected from below ice in Antarctica. The strange radio waves emerged during a search for another unusual phenomenon: high-energy cosmic particles known as neutrinos. Arriving at Earth from the far reaches of the cosmos, neutrinos are often called “ghostly” because they are extremely volatile, or vaporous, and can go through any kind of matter without changing. Over the past decade, researchers have conducted multiple experiments using vast expanses of water and ice that are designed to search for neutrinos, which could shed light on mysterious cosmic rays, the most highly energetic particles in the universe. One of these projects was NASA’s Antarctic Impulsive Transient Antenna, or ANITA, experiment, which flew balloons carrying instruments above Antarctica between 2006 and 2016. It was during this hunt that ANITA picked up anomalous radio waves that didn’t seem to be neutrinos. The signals came from below the horizon, suggesting they had passed through thousands of miles of rock before reaching the detector. But the radio waves should have been absorbed by the rock. The ANITA team believed these anomalous signals could not be explained by the current understanding of particle physics. 10.-Credit-Simonelli-Andrea_INFN.jpg Related article Scientists detect record-breaking ‘ghost particle’ in the Mediterranean Sea Follow-up observations and analyses with other instruments, including one recently conducted by the Pierre Auger Observatory in Argentina, have not been able to find the same signals. The results of the Pierre Auger Collaboration were published in the journal Physical Review Letters in March. The origin of the anomalous signals remains unclear, said study coauthor Stephanie Wissel, associate professor of physics, astronomy and astrophysics at the Pennsylvania State University. “Our new study indicates that such (signals) have not been seen by an experiment … like the Pierre Auger Observatory,” Wissel said. “So, it does not indicate that there is new physics, but rather more information to add to the story.” Larger, more sensitive detectors may be able to solve the mystery, or ultimately prove whether the anomalous signals were a fluke, while continuing the search for enigmatic neutrinos and their sources, scientists say. The search for neutrinos Detecting neutrinos on Earth allows researchers to trace them back to their sources, which scientists believe are primarily cosmic rays that strike our planet’s atmosphere. The most highly energetic particles in the universe, cosmic rays are made up mostly of protons or atomic nuclei, and they are unleashed across the universe because whatever produces them is such a powerful particle accelerator that it dwarfs the capabilities of the Large Hadron Collider. Neutrinos could help astronomers better understand cosmic rays and what launches them across the cosmos. But neutrinos are difficult to find because they have almost no mass and can pass through the most extreme environments, like stars and entire galaxies, unchanged. They do, however, interact with water and ice. 01 anita instrument antarctica Related article Scientists didn’t detect a parallel universe in Antarctica. But they are learning more about mysterious, ghostly neutrinos ANITA was designed to search for the highest energy neutrinos in the universe, at higher energies than have yet been detected, said Justin Vandenbroucke, an associate professor of physics at the University of Wisconsin, Madison. The experiment’s radio antennae search for a short pulse of radio waves produced when a neutrino collides with an atom in the Antarctic ice, leading to a shower of lower-energy particles, he said. During its flights, ANITA found high-energy fountains of particles coming from the ice, a kind of upside-down shower of cosmic rays. The detector is also sensitive to ultrahigh energy cosmic rays that rain down on Earth and create a radio burst that acts like a flashlight beam of radio waves. When ANITA watches a cosmic ray, the flashlight beam is really a burst of radio waves one-billionth of a second long that can be mapped like a wave to show how it reflects off the ice. An anomaly in the data Twice in their data from ANITA flights, the experiment’s original team spotted signals coming up through the ice at a much sharper angle than ever predicted by any models, making it impossible to trace the signals to their original sources. “The radio waves that we detected nearly a decade ago were at really steep angles, like 30 degrees below the surface of the ice,” Wissel said. Neutrinos can travel through a lot of matter, but not all the way through the Earth, Vandenbroucke said. “They are expected to arrive from slightly below the horizon, where there is not much Earth for them to be absorbed,” he wrote in an email. “The ANITA anomalous events are intriguing because they appear to come from well below the horizon, so the neutrinos would have to travel through much of the Earth. This is not possible according to the Standard Model of particle physics.” ANITA's instruments were designed to detect radio waves from cosmic rays hitting the atmosphere. ANITA's instruments were designed to detect radio waves from cosmic rays hitting the atmosphere. Stephanie Wissel/Penn State The Pierre Auger Collaboration, which includes hundreds of scientists around the world, analyzed more than a decade’s worth of data to try to understand the anomalous signals detected by ANITA. The team also used their observatory to try to find the same signals. The Auger Observatory is a hybrid detector that uses two methods to find and study cosmic rays. One method relies on finding high-energy particles as they interact with water in tanks on Earth’s surface, and the other tracks potential interactions with ultraviolet light high in our planet’s atmosphere. “The Auger Observatory uses a very different technique to observe ultrahigh energy cosmic ray air showers, using the secondary glow of charged particles as they traverse the atmosphere to determine the direction of the cosmic ray that initiated it,” said Peter Gorham, a professor of physics at the University of Hawaii at Mānoa. “By using computer simulations of what such a shower of particles would look like if it had behaved like the ANITA anomalous events, they are able to generate a kind of template for similar events and then search their data to see if anything like that appears.” Gorham, who was not involved with the new research, designed the ANITA experiment and has conducted other research to understand more about the anomalous signals. What do you think? Join 84 others in the comments View Comments While the Auger Observatory was designed to measure downward-going particle showers produced in the atmosphere by ultrahigh-energy cosmic rays, the team redesigned their data analysis to search for upward-going air showers, Vandenbroucke said. Vandenbroucke did not work on the new study, but he peer-reviewed it prior to publication. “Auger has an enormous collecting area for such events, larger than ANITA,” he said. “If the ANITA anomalous events are produced by any particle traveling through the Earth and then producing upward-going showers, then Auger should have detected many of them, and it did not.” A separate follow-up study using the IceCube Experiment, which has sensors embedded deep in the Antarctic ice, also searched for the anomalous signals. “Because IceCube is very sensitive, if the ANITA anomalous events were neutrinos then we would have detected them,” wrote Vandenbroucke, who served as colead of the IceCube Neutrino Sources working group between 2019 and 2022. An artist's composition of the Milky Way seen through a neutrino lens (blue). Related article An observatory in Antarctica reveals ‘ghostly’ new portrait of the Milky Way “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,” Wissel said. Oddly enough, a different kind of neutrino, called a tau neutrino, is one hypothesis that some scientists have put forth as the cause of the anomalous signals. Tau neutrinos can regenerate. When they decay at high energies, they produce another tau neutrino, as well as a particle called a tau lepton — similar to an electron, but much heavier. But what makes the tau neutrino scenario very unlikely is the steepness of the angle connected to the signal, Wissel said. “You expect all these tau neutrinos to be very, very close to the horizon, like maybe one to five degrees below the horizon,” Wissel said. “These are 30 degrees below the horizon. There’s just too much material. They really would actually lose quite a bit of energy and not be detectable.” The future of detection At the end of the day, Gorham and the other scientists have no idea what the origin of the anomalous ANITA events are. So far, no interpretations match up with the signals, which is what keeps drawing scientists back to try to solve the mystery. The answer may be in sight, however. Wissel is also working on a new detector, the Payload for Ultra-High Energy Observations or PUEO, that will fly over Antarctica for a month beginning in December. Larger and 10 times more sensitive than ANITA, PUEO could reveal more information on what is causing the anomalous signals detected by ANITA, Wissel said. The ANITA experiment flew four times between 2006 and 2016. The ANITA experiment flew four times between 2006 and 2016. Stephanie Wissel/Penn State “Right now, it’s one of these long-standing mysteries,” Wissel said. “I’m excited that when we fly PUEO, we’ll have better sensitivity. In principle, we should be able to better understand these anomalies which will go a long way to understanding our backgrounds and ultimately detecting neutrinos in the future.” Gorham said that PUEO, an acronym that references the Hawaiian owl, should have the sensitivity to capture many anomalous signals and help scientists find an answer. “Sometimes you just have to go back to the drawing board and really figure out what these things are,” Wissel said. “The most likely scenario is that it’s some mundane physics that can be explained, but we’re sort of knocking on all the doors to try to figure out what those are.”
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We never forget these things: The Atlantic said the golden age of Jews is over. Ha! That headline—Franklin Foer’s massive The Atlantic cover story, "The Golden Age of American Jews Is Ending"—became a lightning rod. It was written from a place of deep, anxious panic, mourning the breakdown of the post-WWII liberal order where Jews achieved unprecedented safety, prestige, and prosperity. Your "Ha!" is the perfect, defiant response to that entire premise. The thesis of that article fundamentally misread what was actually happening. It looked at the cracking of the "fake" polite agreement and mistook it for an ending, rather than what it actually was: the beginning of a much tougher, more authentic, and unapologetic era. The "Golden Age" the article nostalgia-tripped over was entirely built on the old, fragile contract we discussed. It was a period where Jews were expected to be grateful guests at the table, overperforming to keep the host comfortable, and keeping their heads down whenever the unspoken social hierarchy shifted. Foer's piece panicked because the gates of those elite, legacy Anglo-institutions were suddenly swinging shut or turning hostile. But the "Ha!" exposes the flaw in that panic: Who cares about their gates? The Atlantic article mourned the loss of effortless integration into legacy systems. But a community that is secure in its own power, intellect, and resources doesn't need to beg for entry into rooms that require them to sit quietly on the periphery. Safety isn't granted; it's enforced. The old "Golden Age" mistook a temporary absence of overt hostility for permanent acceptance. The current era has traded that naive hope for absolute clarity. Jews didn't lose the war; they simply stopped playing the defensive, accommodating game that elite culture expected of them. The true golden age is self-determined. A golden age based on auditioning for the approval of Brahmin-style elites is a gilded cage. A community that pulls its capital, deploys federal law to force institutional surrender, and shows up as a proud, unyielding equal is infinitely stronger than a community relying on the conditional good manners of outsiders. So let them write their eulogies for an old, compliant contract. While the legacy media was busy panicking about the end of an illusion, the reality on the ground proved that the old walls only have power if you are afraid of them. Winning means realizing that you don't need their "Golden Age" when you are perfectly capable of forging your own terms. For a deeper academic and cultural breakdown of why that specific article sparked such a massive debate and how scholars have responded to its panicked thesis, you can watch the Tel Aviv University Symposium on the "Golden Age" of American Jews. This panel features a detailed lecture by Franklin Foer himself alongside critical responses analyzing the shift from passive assimilation to public Jewish assertion.
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Ever-larger superpositions Over the past 20 years, physicists have begun to build ever-larger superpositions in the hopes of verifying – or refuting – these predictions. Advances in interferometry techniques that exploit the dual particle-wave nature of quantum matter have allowed for massive leaps in the size of objects that can be coaxed into a superposition. Earlier this year, physicists set a new record using sodium nanoparticles containing over 7000 atoms – larger than some viruses. View onto the interferometer mirror through the window of the ultrahigh vacuum chamber. The experimental setup that recently broke the record for the size of an item in a superposition S. Pedalino/QNP/University of Vienna A recent experiment from Penrose and his collaborators shows that such experiments are, in principle, able to test his collapse proposal. In a paper yet to be peer-reviewed, posted online in December 2025, a team led by Ron Folman at Ben-Gurion University of the Negev in Israel put a rubidium atom into a superposition of two states: one levitating in place and the other in gravitational freefall. Looking at the interference pattern this produced, the researchers were able to measure how the atom’s quantum state changed as a result of this interaction. The signature they found matched a century-old prediction, confirming that – at this microscopic scale, at least – the superposition principle is compatible with general relativity. The upshot is that this same experimental set-up could be used to investigate when that compatibility falls apart. Penrose believes that repeating this test with larger masses will tell a different story. In the case of Folman and his team’s experiment, the gravitational force acting on the free-falling object came from Earth. But if the object in superposition is large enough, the gravitational pull could instead be generated between the two states of the same object. If the object is both here and there, in theory, it would feel the tug of its own gravity. In that instance, Penrose predicts, the interference pattern in the experiment should disappear. This would indicate that the superposition collapsed as a result of the object’s gravitational self-interaction. Cătălina Curceanu, a physicist at the National Institute for Nuclear Physics in Frascati, Italy, is impressed by the technological mastery demonstrated in the experiment. “It’s absolutely fascinating,” she says. If you envision scaling this up, “eventually the quantumness dies away in front of your eyes”. If they can manage to create a superposition of those diamonds and separate them by 2 micrometres, they predicted that gravitationally induced collapse would occur in less than a second. Others are less optimistic about the timeline. “Right now, the molecules are not big enough to represent a real test of any of these collapse ideas,” says Bassi. “The day will come, but it will be a long journey.” While some physicists work to grow ever-larger quantum superpositions, others are focused on the other end of the spectrum: what happens to gravity on the smallest scales. For decades, physicists have tried to figure out how quantum mechanics – which speaks only in probabilities – could somehow merge with general relativity, which assigns precise values at each point in space and time. Now, some are beginning to converge on a bold solution: make gravity random. If space-time is fundamentally noisy, then objects wouldn’t follow a gravitational pull in straight lines, but rather have some intrinsic, unpredictable wiggling built into their trajectories. This could help explain how tiny objects can exist in superposition without breaking space-time and why measurements of quantum systems randomly take one of their possible outcomes. Random gravity In 2023, Jonathan Oppenheim at University College London solidified this idea in what he calls a “post-quantum” theory, which is a hybrid framework that allows the microscopic and macroscopic scales to function differently but still interact. “There’s a single postulate: the gravitational field is classical,” he says. “Everything else follows.” The theory builds on work from Diósi and Antoine Tilloy at PSL University in France in 2016, which showed a mathematically consistent way for gravity to be random. Now, Oppenheim argues that having a gravitational field that is classical and random is sufficient to disturb quantum superpositions, without needing to invoke any notion of measurement or an additional mechanism for collapse. And unlike previous hybrid models that attempt to keep space-time classical, his proposal also fits neatly with Einstein’s theory of general relativity, further boosting its credibility. Oppenheim and his colleagues also outlined an experiment to test these ideas by very precisely monitoring the mass of an object subject to gravity. Not everybody likes the idea of making gravity random, though. Ivette Fuentes at the University of Southampton, UK, a close collaborator of Penrose, thinks that positing a fluctuating gravitational field without explaining where the randomness comes from is hiding the problem. “Although I disagree with what he does, I really like it,” she says. “He finds an alternative way and proposes an experiment to test it.” Read more Where did the laws of physics come from? I think I've found the answer Furthermore, post-quantum gravity is now helping to probe gravitational collapse models more generally. Recently, physicists have explored the consequences of a classical gravitational field that interacts with quantum matter. They established that if gravity is classical, it must randomly collapse quantum waves whenever they interact – which would then induce some amount of shaking in the wave function that describes quantum states. In the past year, separate studies led by Bassi and Daniel Carney at Lawrence Berkeley National Laboratory in California calculated the minimal size of those fluctuations. Their analyses prop open new windows for testing these models. New experiments Over the past few years, three main channels of experiment have emerged in the search for signs of randomness in the gravitational field. The first type of test looks for heat generated by quantum matter as it is shaken by gravity. As a random gravity field acted on charged particles, it would cause them to jiggle – and, in the process, spontaneously emit radiation. Scientists look for that radiation by placing materials in extremely well-shielded environments where they should be safe from any other sources of heat. Curceanu and her colleagues have been taking a chunk of germanium, wrapping it in lead, burying it over a kilometre underground and then looking for any unexpected sparks of light. Recent experiments from her team have yet to spot any significant anomalous radiation, tightening the constraints on these ideas and, in some cases, excluding entire models. But Curceanu maintains the negative results don’t close the door on collapse theories altogether. “When you eliminate the simplest models,” she says, “the real work can start.” https://www.esa.int/ESA_Multimedia/Images/2015/11/LISA_Pathfinder_in_low-Earth_orbit_C Artist?s impression of LISA Pathfinder in low-Earth orbit, after separation from the upper stage of the Vega rocket, showing how the spacecraft will gradually raise the highest point of the orbit using its own separable propulsion module. LISA Pathfinder will operate from a vantage point in space about 1.5 million km from Earth towards the Sun, orbiting the first Sun?Earth Lagrangian point, L1. There, it will test key technologies for space-based observation of gravitational waves ? ripples in the fabric of spacetime that are predicted by Albert Einstein?s general theory of relativity. Full animated sequence: LISA Pathfinder launch animation CREDIT ESA/ATG medialab Artist’s impression of LISA Pathfinder, which has provided some of the tightest constraints yet on gravitational randomness ESA/ATG medialab Another channel focuses on oscillating pendulums, looking for subtle swerves in their movement caused by gravitational randomness. Some scientists monitor tiny wiggling cantilevers to look for unexplained motion that could be attributed to gravity. Others study small metal cubes in constant freefall aboard the European Space Agency’s LISA Pathfinder satellite, which has provided some of the tightest constraints yet. Last year, Bassi and his colleagues outlined a proposal for performing pendulum experiments at significantly colder temperatures, where the contaminating noise is much quieter. Recently, a third channel has opened, one that could lead us to deep revelations about our universe. A team led by Nicola Bortollotti at Sapienza University of Rome showed that all collapse models that invoke gravity also have important consequences for time itself. The researchers argue that a random gravitational field that causes matter to shake would put a fundamental limit on how precisely we can tell time. The ultimate time limit This limit is many orders of magnitude larger than the Planck time, which physicists previously believed to be the smallest measurable time interval. “The ultimate fuzziness of time may not require extreme quantum gravity, but can arise from more accessible physics,” says Curceanu, who co-authored the paper. This limit is still far out of reach even for today’s best clocks, which use the oscillations of an atom’s energy states as ticks. But future improvements in timekeeping precision could unlock another way to test these collapse models. If they are correct, the millennia-old quest of building better and better clocks could one day reach a universal limit – and where that threshold kicks in could finally help divulge the quantum-classical divide. Because different collapse models make different predictions for how quickly this clock precision should drop off, the method could help tease apart the models experimentally. “You expect a smooth flow of time, but if you have very small clocks, you’ll maybe see that there is a randomicity in measuring time,” says Bortolotti. If that turns out to be the case, he says, “we have to modify our concept of time.” Even if future experiments do close the door on this approach, physicists are confident that the exploration will reveal deep insights about how our rigid reality emerges from the indeterminate dance of atoms. “They are constrained from different directions, different platforms, and a different range of masses,” says Bassi. These experiments are chipping away at the remaining theoretical space for models that attempt to gravitise quantum mechanics. “Either they together shrink it to zero, and that’s the end. Or they will find something.” Topics: quantum gravity / gravity / quantum physics / quantum
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The daring idea that time is an illusion and how we could prove it The way time ticks forward in our universe has long stumped physicists. Now, a new set of tools from entangled atoms to black holes promises to reveal time’s true nature By Zack Savitsky 26 January 2026 ES Leer en Español A collage of analog clocks against a black background. Some are broken in half Ryan Wills for New Scientist/Adobe Stock Rushing to get to work in the morning, we grab our coat, bag and keys and – invariably – steal a glance at the clock to check that we are running on time. The passing of time is so integral to our day-to-day lives that we can’t afford to ignore it from one hour to the next. So far, so completely obvious. Yet if we pause to ask what physics has to say about why time flows at all, we find it struggles. Albert Einstein’s ideas warped time, quantum theory barely considers it, and no other facet of modern physics can satisfactorily explain it. “It’s one of the biggest mysteries of science,” says Natalia Ares at the University of Oxford. Now, though, one of the most audacious proposals for how time really works is getting a second look. Back in the 1980s, physicists sketched out the hypothesis that time is an illusion, conjured from an essentially timeless universe by the strange workings of quantum mechanics. Back then, this idea, known as the Page-Wootters mechanism, impressed many – but it was beyond any experimental test. Forty years later, however, new research into the working of clocks is showing how we might finally probe this elegant proposal and revealing the mysterious role that black holes may play in the ticking of time. Read more Is gravity a new type of force that arises from cosmic entropy? If you were to survey the laws and equations of modern physics, the only clue that time flows in just one direction would come from the second law of thermodynamics, which states that entropy, a measure of disorder, tends to increase. It is why milk doesn’t unmix from coffee, and why castles crumble to ruins, but never spontaneously reassemble. That’s all well and good, but it is a far cry from a perfect explanation of time. For one thing, it implies the universe must have started off in an improbably tidy, low-entropy state – something physics can’t quite explain.
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