Static electricity is one of those everyday phenomena that turns out to be much more complicated than you might expect. Indeed, our guest in this episode of the Physics World Weekly podcast has devoted much of his career to understanding how objects exchange electrical charge – a process that he says scientists are mostly “clueless” about.
Based at the Institute of Science and Technology Austria, Scott Waitukaitis is in conversation with Physics World’s Margaret Harris. He explains how his early work in granular physics opened his eyes to the many unsolved problems related to static electricity. They also chat about some of Waitukaitis’s current research projects including his quest to understand the role that adsorbed molecules play in how an object is charged.
A 201-million-year-old climate catastrophe turned Europe into a landscape of fern savannahs that repeatedly caught fire, according to new research published in the journal Nature Geoscience.
A head-on collision with another galaxy billions of years ago may have dramatically reoriented the Milky Way’s disk, according to new supercomputer simulations that reveal how violent mergers can leave spiral galaxies looking surprisingly normal today.
Researchers at the University of Michigan have created a device that enables them to control the flow of electrons through a semiconductor using only laser light—no electrical power source required.
When two pulses of different colored lasers (the two waves at the top of the image) light meet in a new device created at the University of Michigan, researchers create a beam of electrons (small golden particles) that flows in a controllable direction. By changing the laser colors, the electron beam can sweep through different directions like the beam of a lighthouse. Illustration: Yiming Gong
This device was built 1 to explore fundamental physics and realize a previously unobserved behavior, but it could also open doors for new applications in areas that bridge optics and electronics, including sensing, imaging and telecommunications. The phenomenon could help improve how signals are sent through and between devices, as well as create new opportunities to store more information in those signals.
“This electrical device that we manufactured at the Lurie Nanofabrication Facility has the potential to turn into something that measures different aspects of light,” said Yiming Gong, who helped lead the project as a doctoral student in the U-M Department of Physics. “But this originates from a very fundamental level of physics, which is the interference between different optical absorption processes.”
The researchers showed they could induce the orderly flow of electrons through a semiconductor using two different colors of light. By rotating the polarization of the two optical fields—the direction that the light waves wiggle—the researchers could also control the direction of the electronic current.
“This isn’t the way things normally work. When you think about electrons moving through a material, they’re moving because you’ve applied an electrical field and they actually bounce around and drift across the materials. Here, using light, you can actually sort of squirt the electrons in a specific direction without applying an electric field,” said U-M physicist Steven Cundiff, senior author of the team’s report.
Although previous work had shown the ability of light to get electrons flowing with light alone, this work goes a step further and shows the light gets electrons flowing in a narrow beam in a specific direction.
“The light no longer merely switches the current on; it also aims it,” Cundiff said.
Cundiff likens this to a lighthouse, which sweeps a beam of light by rotating its lamp. Here, the beam is made of electrons and that beam can be rotated by rotating the polarization of the two phase-coherent optical fields.
The phenomenon relies on quantum interference, which arises when two colors of light drive different absorption pathways to the same final state. The light transfers energy to the semiconductor material in discrete, or quantized, packets called photons, which mobilize the material’s electric charge carriers.
In the set-up, the incident light is absorbed by two routes at once, and the routes can be thought of as overlapping ripples, Cundiff said. Those ripples line up and enhance each other for electrons traveling a certain direction, but cancel each other out for electrons moving in other directions.
A collaborator on an earlier project, J.E. Sipe of the University of Toronto, had predicted it would be possible to create such an “electron lighthouse.” Now, working with the Lurie Nanofabrication Facility, Gong was able to realize such a device.
“The LNF is an amazing facility,” Gong said, adding it was a painstaking process to meld the device’s materials together in a way that didn’t introduce any extraneous electric fields.
“That was the biggest puzzle to solve for me, because there isn’t a standard way to do that. So I worked with the LNF staff to play around with different recipes and temperatures to come up with a manufacturing process.”
References
Yiming Gong, Kai Wang, and Steven T. Cundiff (2026) Directional Photocurrent Generated by Quantum Interference Control Phys. Rev. Lett. doi: 10.1103/3v91-5pzf↩
Using the largest sample yet of particles called beauty mesons, physicists with the CMS Collaboration at CERN’s Large Hadron Collider (LHC) refined a decades-old test of the subtle imbalance that let our Universe exist at all.
This image, which combines a background view from the Dark Energy Camera Legacy Survey with two inset images from the Very Large Telescope, shows an unusual pair of galaxies in the Fornax Cluster. The galaxies FCC 224 and FCC 240 are under scrutiny because they may have formed via a high-velocity collision between dwarf galaxies — the so-called “bullet-dwarf” model. Using new spectroscopy from the Very Large Telescope, Maria Luísa Buzzo (Yale University) and collaborators analyzed the ages and kinematics of the galaxies’ stars as well as the unusually bright globular clusters swirling around each galaxy. These data suggest that both galaxies are deficient in dark matter, and their stellar populations and globular clusters are all roughly 10 billion years old. The lack of dark matter and the uniform stellar ages are both consistent with the bullet-dwarf model, in which the collision strips away dark matter and ignites a burst of star formation. Since this type of collision can create more than two remnants, the team suggests searching along the trajectory defined by FCC 224 and FCC 240 for more fragments from the collision, some of which may contain the galaxies’ lost dark matter. To learn more about these galaxies and what they might mean for the bullet-dwarf mechanism, be sure to check out the full research article linked below.
Citation
“Dark-Matter-Deficient Twins: FCC 224 and FCC 240 as Possible Analogs of NGC 1052-DF2 and DF4,” Maria Luísa Buzzo et al 2026 ApJ1005 15. doi:10.3847/1538-4357/ae7349
I had a simple task that involved Apple Home. If you use Apple Home, you know what happened next. Tears, frustration, the arrival of batteries, paperclips pushed into hard-to-reach holes, many online searches, and—if you are lucky, as I was—success.
Siri, am I lazy?
My goal was straightforward: can I know if the garage door is open without going to look? Early in the pandemic, we occasionally forgot to close it. While there was a locked door between the garage and the house, it still felt like we were playing with fire, as someone could steal a bike or other lesser goodies from the garage.1 The garage is on our basement floor (ground level on one half of the house), and the last thing I enjoy doing at night is walking downstairs before bed to check the door.2
I purchased an Eve Door & Window Contact Sensor to have this capability reported by Apple Home, joining a growing set of HomeKit devices, including our front-door deadbolt. Because of our old-style single-piece swing-up garage door, I had a heck of a time finding the right place and right adhesive to stick the sensor where it was close enough for the two components to register.
The red-on-pink Characteristic is Shortcuts tells me it couldn’t read anything back from the sensor.
I spent enough time on the vagaries of physics and materials that I was probably more frustrated than I needed to be when I tried to make a workflow with the danged thing. An Automation wouldn’t work because I wanted an alert, not for the sensor to trigger other Home devices. A Shortcut should have worked, but after many hours of trying over weeks, I was unable to get anything reliable to happen. The Automation was quite simple: at 9 p.m., check the state of the sensor, and send me a message if the sensor shows Open rather than Closed. I left it in place and walked away for literally years.
After recently installing a back-driveway camera, I was determined to get this sensor online.3 First, I replaced the battery, which had died during my period of disinterest. The Eve sensor uses a weird, tiny battery: a 3.6V 1/2 AA (ER14250). After that arrived, using some better adhesive—thin-film 3M 468MP—I positioned the sensor pieces in a better location and more securely.
Now it should work! Except that after adding it, I saw Characteristic in red text on a pink background in Shortcuts. Some online research led me to reset the sensor by inserting a paperclip into a hole I hadn’t noticed. After re-pairing the sensor, I was in business! Or was I?! The sensor wasn’t responding, despite recent status updates.
Threading the sensor through the house needle
The working Shortcut tests for the garage door sensor‘s state being Open or Closed, and acts accordingly.
This led me to the next culprit: the garage is too far away (one floor and the other end of the house) from my Apple TV, which acts as a Matter controller, while the Eve sensor relies on Thread as its communication protocol. What’s a Matter controller?4 And what’s Thread?
Matter is an overarching standard, painstakingly developed even as low-power sensing devices and other equipment proliferated in silos. Matter enables Amazon Alexa, Apple Home, Google Home, and Samsung SmartThings devices to communicate across a network, regardless of the network transport medium (Ethernet, Thread, or Wi-Fi). This prevents you from needing ecosystem-specific hubs and lets manufacturers build to a common standard.
Thread fits into this mix as a low-power, wireless networking standard for sensors, allowing them to communicate their status without rapidly draining their batteries, as would happen with Wi-Fi.5 Apple initially supported Thread with a proprietary standard, HomeKit-over-Thread, and later added direct Matter support. The Eve sensor was just old enough that it was running on the older standard, but the Eve app allowed me to apply a firmware upgrade. I could then migrate the sensor to Matter, which seems to be more reliable.
Apple made things a little confusing here, too. The 1st-generation Apple TV 4K supports Matter, but lacks a Thread radio, so it can’t work with Thread-based devices. The 2nd generation added that radio, so you can do Matter over Thread. But then, with the 3rd generation, Apple bifurcated Thread hardware support: the 64 GB Wi-Fi only model lacks a Thread radio; you have to spend the now-whopping $249 for a 128 GB Wi-Fi + Ethernet version if you want to use Thread.
Failing an Apple TV 4K with Thread, you can use a Thread border router (TBR), which sometimes comes with sensor kits. This plugs into your network via Wi-Fi or Ethernet and bridges to the Thread network, allowing the Apple TV’s Matter controller to work with the Home app on your devices for automations, notifications, and so forth.
It’s that easy, folks. Sigh.
I do own a 3rd-generation Apple TV 4K with Wi-Fi + Ethernet, because I am a fancy man and a big spender, but I really wanted the reliability of plugging it into my Ethernet network. Yet, I couldn’t get the Eve sensor’s Thread radio to reach across my house to talk to the Apple TV. I bought a TBR, thinking it would solve the problem.
By the time the TBR was delivered, however, the garage door sensor magically connected via Thread to the Apple TV and has been rock solid. The TBR that arrived, on the other hand, I was unable to pair and get working, so back it goes for a refund.
Now my nightly Shortcut works! The only fly in that ointment is that the sensor status reports as Closed or Open in iOS and iPadOS, but as 0 (closed) or 1 (open) in the macOS Home app, in both macOS 26 and the beta of 27. I can live with running the Shortcut from my phone.
Shortcuts in macOS can’t seem to read the Home sensor’s text labels of Open and Closed, seeing 1 and 0 instead.
[Got a question for the column? You can email glenn@sixcolors.com or use/glennin our subscriber-only Discord community.]
Bikes were in short supply and sold at outrageous prices in the early pandemic, partly because supply chains to import new ones were halted. Then, there was a glut when life allegedly returned to normal. ↩
I mean, I don’t enjoy doing it as the final thing of the evening. English is complicated. The last thing I enjoy doing before bed is some crossword puzzles while listening to a podcast. ↩
New research is revealing possible links between one of the most enduring cosmic mysteries—dark matter—and the existence of a “hidden” fifth dimension.
Dark matter is widely believed to exist according to several leading cosmological theories, although this nonluminous material remains invisible through direct detection. However, its presence can be inferred through the gravitational influence this mysterious form of matter has on the surrounding universe.
Now, according to researchers at the University of Sheffield, one reason dark matter may have remained so elusive involves the possibility that it exists within a “hidden” dimension—a concept that has gained traction in past research.
The Sheffield team’s recent look at this possibility, detailed in a study published in Physical Review D, takes the concept one step further by introducing a new potential framework that could help reveal clues to the behavior of dark matter, as well as why astronomers have had such a hard time detecting it.
A Dark Secret Lurking in a Hidden Dimension?
In their new research, the Sheffield team says that dark matter may be lurking within a hidden dimension accompanied by dark photons, a variety of particles among those which physicists call “hidden sector particles,” and which are believed to represent potential force carriers for dark matter.
Due to the specific geometry present within this hidden dimension, a phenomenon known as dark matter resonance may occur, where dark photons align in specific arrangements.
“Dark matter resonance is already known to be a powerful idea,” according to Yu-Dai Tsai, Ph.D., a Royal Society Dorothy Hodgkin Senior Research Fellow at the University of Sheffield and one of the new paper’s coauthors.
Tsai adds that the concept has “the potential to change our understanding of how dark matter was produced in the early universe and how we search for it today,” although reconciling it with our current understanding of dark matter has presented issues for researchers in the past, which include questions about its specific origins.
“Many previous resonant dark matter models have treated the resonance as an assumption,” Tsai recently said in a statement. “[Our team’s] work gives a possible deeper origin for it: The resonance may come directly from the geometry of hidden dimensions.”
Unlocking Dark Matter Resonance
According to Tsai and his co-author, Taegyu Lee, understanding dark matter resonance more fully could hold significant implications for unlocking new clues about how matter behaved at early stages in our universe, and why that may differ significantly from what astrophysicists see occurring right now.
“This resonance can make dark matter interactions much stronger at crucial epochs in cosmic history,” Tsai says. “Crucially, the model allows for these strong interactions in the past while still explaining why dark matter appears so inert and hard to detect today.”
Although Tsai concedes that the concept of dark matter resonance has been explored in the past, unlike previous studies, the Sheffield duo’s new work suggests that dark matter may essentially be “in tune” with conditions in a hidden fifth dimension already, arising naturally from its innate mathematical structure.
Tsai says this approach toward understanding dark matter, if correct, “would represent a profound advance in humanity’s knowledge of the cosmos and what it is made of.”
A New Approach Toward Unraveling Dark Matter’s Mysteries
Fundamentally, the team’s findings point to promising new ways physicists may be able to explore the underlying mysteries of both dark matter and the possibility of additional dimensions in which it may operate.
“Our research gives physicists clear new targets in the search for dark matter,” Tsai says, “while connecting two of the biggest ideas in fundamental physics: the mystery of dark matter and the existence of hidden dimensions.”
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached atmicah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.
Dark matter interactions may be a hidden “dark force,” unexpectedly constraining our Universe’s expansion and structural development, according to researchers.
In a recent paper published in the Journal of Cosmology and Astroparticle Physics, researchers identified unexpected effects arising from dark matter particles interacting with one another and clustering via a hidden dark force.
Typically, scientists can only study the invisible—and still purely theoretical—dark matter through its gravitational effects on ordinary matter. However, the new research explores how dark matter may also influence itself.
Exploring the Dark Force
As scientific instruments become more precise, researchers continue to uncover mysteries once hidden at the fuzzy edges of our understanding of the cosmos. One such puzzle involves discrepancies in measurements of the Universe’s density over time. Within the widely accepted ΛCDM model of cosmology, observations of cosmic expansion and the growth of large-scale structures have not always aligned with theoretical expectations.
To address these tensions, researchers have proposed a theoretical dark force—a previously unrecognized attractive force that acts only between dark matter particles. Such a force could influence both the expansion of the Universe and the formation of cosmic structures, potentially helping reconcile current models with recent observations.
“What we really know about dark matter has so far been learned only through its gravitational effects,” said co-author Zachary Weiner, a researcher at the Perimeter Institute for Theoretical Physics. “That leaves open the possibility that dark matter might have additional interactions that are hidden from ordinary matter.”
Investigating the Dark Force
The researchers examined models in which dark matter particles interact through a long-range force beyond gravity. By combining cosmological observations with theoretical calculations, they searched for evidence of how such a force might affect both the growth of cosmic structures and the expansion history of the Universe.
At first glance, the prediction seemed straightforward: if an additional attractive force pulls dark matter particles together, it should enhance their ability to cluster, potentially explaining why some observations suggest a denser cosmic landscape than expected.
“The first thing you would expect is that giving dark matter an additional attractive force should make structures grow faster,” Weiner explained. “But another effect comes into play at the same time.”
A Surprising Discovery
The researchers’ results revealed a more complicated picture. While a dark force does cause dark matter to cluster more efficiently, it also alters the expansion of the Universe in a way that causes dark matter particles to become effectively lighter over time.
As a result, the additional clustering is not strong enough to significantly increase matter’s gravitational imprint on the cosmic microwave background. Instead, the net effect is to suppress the overall growth of cosmic structure.
According to the researchers, this previously unrecognized interaction could play an important role in new cosmological models developed to explain observations from the Dark Energy Spectroscopic Instrument (DESI) in Tucson, Arizona. If confirmed, the effects of a dark force may need to be incorporated into future efforts to understand the evolution of the Universe.
As astronomers peer farther into space and deeper into cosmic history with ever-greater precision, studies like this may help explain subtle discrepancies that have long remained hidden.
“The Universe is often more subtle than our intuition,” Weiner concluded. “That’s exactly why we have to keep testing these ideas.”
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.
Building electronic devices often requires stacking different crystalline materials on top of one another with atomic precision. This process, called heteroepitaxy, works best when the two crystals share similar atomic patterns. When their symmetries differ, the upper crystal tends to grow in several orientations at once instead of a single one, creating defects that degrade device performance. Engineers have long dealt with this problem by treating the surface of the lower crystal beforehand, for example by etching steps into it, exposing it to plasma, or adding a buffer layer, to help the two materials bond more effectively. Now, a team of researchers explores 1 a different route: rather than forcing the two crystals to fit together, it takes advantage of a crystal that is naturally flexible at the atomic scale.
Flexible by design
The material at the center of this approach is a layered compound called TaCo2Te2. Like graphite, its layers are held together by weak van der Waals forces, which makes it easy to combine with other materials without demanding a perfect chemical match. Unlike most layered crystals, though, its atoms are not arranged in a perfectly regular pattern. At room temperature they undergo a small, periodic shift known as a Peierls distortion, a phenomenon first described in the 1930s by the physicist Rudolf Peierls, who showed that in some materials the electrons and the surrounding lattice can lower their combined energy by nudging atoms slightly out of their ideal positions. When TaCo2Te2 is heated above about 523 kelvin, or 250 degrees Celsius, this distortion disappears and the crystal adopts a more symmetric structure, although traces of the original pattern linger as fleeting, temperature-driven fluctuations.
These fluctuations are not random. Calculations of how the crystal vibrates, backed up by Raman spectroscopy and electron diffraction experiments, show that the lattice is especially unstable along one crystallographic direction, meaning atoms can shift more easily there than in the perpendicular direction. This directional softness turns out to be the key ingredient that controls how a second material grows on the surface.
Heating TaCo2Te2 also sets its atoms in motion across the surface. Tantalum atoms drift away, while cobalt and tellurium reorganize into a thin crystalline layer whose composition resembles cobalt telluride. Rather than clumping into isolated islands, this new layer spreads sideways first and only then thickens, producing a smooth, continuous interface with the crystal beneath it, a layer-by-layer growth style that electron microscopy confirms is energetically favorable.
Directionally locked
The most striking result is that the new crystal does not settle into just any orientation. Even though its symmetry differs from that of the underlying TaCo2Te2, it becomes directionally locked. Along one in-plane direction, the atomic spacings of the two materials match closely, giving a tight, well-ordered registry. Along the perpendicular direction the mismatch is far larger, but this happens to be exactly the direction where TaCo2Te2 is most flexible, thanks to its lattice instability. Instead of rotating to relieve that mismatch, as symmetry-mismatched interfaces typically do, the interface absorbs it through a gentle, ongoing structural adjustment. The result is a crystal that stays aligned while only one direction bears most of the strain.
That flexible direction does not settle into a simple repeating pattern either. Instead, it forms what is called a one-dimensional incommensurate superlattice: the repeating atomic spacings of the two crystals never line up exactly, yet they stay locked together over long distances. Physicists have long recognized this kind of arrangement as an efficient way to accommodate mismatched lattice spacings without piling up large numbers of defects, since the strain is spread out through a slowly changing modulation rather than concentrated at sharp boundaries. Diffraction measurements and a geometric analysis of the two lattices both confirm that no perfectly repeating, shared lattice can account for what is observed, so the incommensurate description fits best.
Directional lattice instability is key
To check that the lattice instability is truly responsible for this behavior, the same experiment was repeated with a closely related compound, TaNi2Te2, which has nearly the same crystal structure but lacks the structural instability. Under similar heating, a surface layer still forms, but its orientation varies from spot to spot, and rotational disorder sets in. This comparison shows that matching crystal symmetry is not enough on its own to produce a locked, well-ordered interface. The directional lattice instability is the extra ingredient that guides the growth.
The local reconstruction effect
One more effect helps stabilize the interface. Even above the temperature where the bulk crystal should be fully symmetric, the atomic layers right beneath the interface partly slip back into the low-temperature distorted structure. This local reconstruction stays confined to the surface rather than spreading through the whole crystal, and it appears to strengthen the bond between the two materials, keeping the aligned structure stable even at high temperature.
As we have just seen, structural instabilities, usually considered as a liability because they signal that a crystal is on the verge of changing shape, can instead become useful design tools. A substrate whose atoms rearrange more easily in certain directions can guide the growth of otherwise incompatible materials, producing well-aligned interfaces without extensive surface treatment. This idea could widen the range of material combinations available for future electronic, optical, and quantum devices, where the atomic arrangement at an interface often determines how well the whole device performs.
Author: César Tomé López is a science writer and the editor of Mapping Ignorance
Disclaimer: Parts of this article may have been copied verbatim or almost verbatim from the referenced research paper/s.
References
Nitish Mathur, Guangming Cheng, Francesc Ballester, Gabrielle Carrel, Vincent M. Plisson, Fang Yuan, Jiangchang Zheng, Caiyun Chen, Scott B. Lee, Ratnadwip Singha, Sudipta Chatterjee, Kenji Watanabe, Takashi Taniguchi, Kenneth S. Burch, Berthold Jäck, Ion Errea, Maia G. Vergniory, Nan Yao, Sanfeng Wu, and Leslie M. Schoop (2026) Directionally Locked Heteroepitaxy with a Structurally Modulated van der Waals Material ACS Nano doi: 10.1021/acsnano.6c04146↩
Hue’s latest smart bulbs will be able to run Zigbee and Thread concurrently. | Photo by Jennifer Pattison Tuohy / The Verge
Philips Hue has announced a connectivity upgrade for its Matter-over-Thread-enabled smart bulbs that will allow them to run both Thread and Zigbee at the same time. The change means you can connect compatible Hue bulbs and fixtures directly to a Matter ecosystem - Apple Home, Amazon Alexa, or Google Home - while keeping them linked to a Hue Bridge and the Hue ecosystem.
"Today you cannot have Zigbee and Thread running at the same time, so when you commission it, you have to choose," Philips Hue CTO George Yianni told The Verge. "If you want to then later switch, you have to reset it."
I further develop "spiritual physics" to explore the dynamics of UFOs, linking their behavior to concepts of exotic energy and matter. By applying Newtonian kinematics and imaginary numbers, the model suggests UFOs harness unseen energy and achieve incredible speeds. The interplay between real and imaginary mass could explain their elusive movements.
The exploration of faster-than-light travel, particularly through the concept of warp drive, presents significant theoretical challenges. While models exist, such as the Alcubierre drive, practical implementation remains impossible due to the non-existence of the required negative energy. Thus human exploration of neighboring star systems must be concluded as impossible.
The Bullet Cluster is one of the most famous objects in astronomy. For years, many scientists have considered it one of the strongest pieces of evidence for the existence of dark matter, the mysterious substance thought to make up most of the matter in the universe. However, a new study suggests there may be another […]
New research reveals how an unusual celestial object resembling a cosmic “bullseye” could offer clues to one of the most perplexing phenomena in our universe.
The research, undertaken by physicists Pierre Sikivie and Yuxin Zhao at the University of Florida, focuses on an astronomical feature quite unlike any other—the galaxy LEDA 1313424, whose concentric rings have garnered it the apt nickname of the “Bullseye galaxy.”
Based on Sikivie and Zhao’s recent research, detailed in a new paper that appeared in The Astrophysical Journal, quantum behavior related to long-mysterious dark matter may hold the key to the galaxy’s unusual appearance.
Unraveling a Bullseye Galaxy’s Circular Secrets
In the past, astronomers have attempted to explain LEDA 1313424’s unusual concentric appearance as the likely result of an ancient collision between two galaxies.
Not so, according to Sikivie and Zhao, who now take a vastly different approach by arguing that a better explanation may involve a Bose-Einstein condensate of axions, a variety of extremely light hypothetical particles.
A stunning Hubble Telescope view of the Bullseye galaxy (Image Credit: NASA, ESA, I. Pasha (Yale), P. van Dokkum (Yale)).
This concept has much deeper roots that go back close to a century ago, when the first galaxy featuring an unusual concentric ring was discovered. This example, dubbed the Cartwheel galaxy, was only the first in a succession of similar astronomical discoveries involving galaxies with “ringed” appearances that incorporate as many as three annular features.
Unraveling an Annular Enigma
Explaining why these galaxies look this way has remained elusive. One theory proposed by astronomers, as noted earlier, involves impacts between two galaxies, which could create waves of density whose ripples become evident in ring-like structures surrounding the resulting galaxies.
However, a discovery in 2025 by Imad Pasha, a Yale University astronomer, and his colleagues presented an even stranger development in this ongoing concentric saga: the discovery of a galaxy that possesses not three rings, but nine of them. With its discovery, this remarkable celestial object’s unusual appearance garnered the nickname now familiar to us: “The Bullseye galaxy.”
Artist’s concept detailing the annular features encircling LEDA 1313424 (Image Credit: NASA, ESA, Ralf Crawford (STScI))
One theory that astronomers believed may account for the galaxy’s nine concentric structures had been a hypothetical impact—and a very energetic one—that occurred about 56 million years ago. However, while investigating this possibility, Sikivie and Zhao say a problem emerged: this would mean that the outermost ring in the galaxy would have had to travel at a speed of 758 miles per second as it blasted outward from the galaxy’s center.
This speed, they say, is impossible to reconcile with what astronomers can already discern about the nature of the supposed collusion, as well as the well-characterized behavior of galactic material observed in other regions of the cosmos.
An Alternative Approach
In an effort to get to the bottom of the mystery behind this unique galaxy, Sikivie and Zhao have put forward an alternative idea: that the rings in the Bullseye galaxy might instead be a byproduct of dark matter’s mysterious properties.
According to astronomers, dark matter is believed to be a nonluminous material that populates our universe, contributing around 85% of its total mass. Despite its ubiquity, direct detections that could confirm its existence have remained elusive.
However, there are some intriguing cosmic phenomena that astronomers are aware of that are very good candidates for being indirect evidence of this mysterious material. These observations include gravitational motion that occurs in galaxies, whereby the accumulation of dark matter is believed to manifest in the appearance of spherical halos encircling them.
In the past, Sikivie has explored this possibility, and whether current prevailing theories about dark matter, such as the idea that hypothetical particles known as axions, may offer the best interpretation of the physical reality behind dark matter.
If dark matter is indeed related to axions, it would also be required to obey what astrophysicists call conservation of angular momentum. According to Sikivie, when axions and galaxies interact, a phenomenon should emerge where portions of dark matter halos closest to the center would become oriented in structural forms known as “caustic rings.”
“We had earlier proposed that disk galaxies have caustic rings of dark matter with a pattern of ring radii, very similar to the pattern of ring radii observed in LEDA 1313424,” Sikivie recently said.
With this idea in mind, Sikivie and Lhao then turned their attention to the mysterious bullseye of LEDA 1313424 and “fitted the observed ring radii to the pattern of ring radii in the caustic ring interpretation,” from which they discerned that “LEDA’s rings are the imprint of caustic rings of dark matter on the baryonic matter in LEDA’s disk.”
Strange Quantum Behaviors
A further aspect of the researchers’ theory involves the quantum behavior that axions are expected to engage in.
Under extremely cold conditions, these hypothetical dark matter particles could collectively occupy the same quantum state, forming what is known as a Bose-Einstein condensate—a strange state of matter in which quantum effects become visible on macroscopic scales.
According to the team, such a condensate could interact with ordinary matter in ways that match astronomical observations. If the duo is correct, this could imply that ring-shaped galaxies such as LEDA may not result from galactic collisions at all—instead, these unique cosmic structures might be evidence of dark matter axions that have undergone Bose-Einstein condensation.
Presently, much like dark matter, axions have remained hypothetical and frustratingly difficult to detect. Of course, given their elusiveness, this also makes them a very good candidate in terms of helping scientists close in on the dark matter mystery, and new models are helping to provide potentially compelling new resolutions for such problems.
For now, mysterious ringed galaxies remain mysterious. However, as the work of researchers like Sikivie and Lhao progresses, one of astronomy’s more unusual recent discoveries is gradually coming into focus, while providing fresh insight into the intriguing quantum nature of dark matter.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached atmicah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.
The new Thread Networks Diagnostics Tools app from Thread Group, the standards body behind the wireless IoT protocol, officially launches in beta today. The app, which arrives in beta today on iOS and Android, is the first dedicated tool to provide visibility into your Thread-based smart home network. I've been testing the alpha version of the Android app on my complicated home network and, with a bit of extra legwork, have diagnosed several issues with my Thread setup.
Thread is one of the protocols the smart home standard Matter runs on. But since Matter over Thread devices began arriving in 2023, there have been reports of people struggl …
The smart home networking protocol Thread is adding a new way to onboard devices without a Thread border router. The feature, called Thread Direct, is designed to let users set up Thread-powered devices - such as smart plugs and smart locks - using only a phone or mobile device equipped with a Thread radio. Current devices with Thread radios include many iPhones, newer Pixel phones, and the latest Samsung flagships.
Thread is one of the networking technologies used with the smart home interoperability standard Matter. A low-powered, low-latency mesh networking protocol, Thread provides a way for devices to talk to each other locally in your …
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