A spacecraft propelled by a subluminal warp drive would cause an extremely bright glow if it passed through Earth’s atmosphere, according to findings detailed in a new study.

Physicist Shaun Fell from the international think tank Applied Physics (AP) and Harvard astrophysicist Avi Loeb detail their findings in a new paper, which also suggests that extremely small “warp bubbles” could be used as weapons, and that Einstein’s theory of general relativity permits warp bubbles with micrometer-sized surfaces housing very large craft, similar to technologies that appear in science fiction.

The authors emphasize that their new study, which appeared on the preprint server arXiv and has not yet been peer-reviewed, does not prove the existence of aliens, extraterrestrial technology, or warp drives. However, they suggested their analysis offers a viable scientific foundation for many UAP reports of bright lights and “orbs” discussed in recent Pentagon file drops, and is supported by a mathematically valid means of interstellar travel that interplanetary visitors—if they exist—might use to reach Earth.

“Warp drives are a fantastic way to travel through the universe, and it makes sense to my human brain that aliens would find them advantageous too,” Dr. Fell told The Debrief.

Warp Drives: From Science Fiction to Science Fact?

Science fiction authors have proposed ways to travel faster than the speed of light for decades. In the 1960’s, science fiction TV trendsetter Star Trek brought the concept to the wider public with the U.S.S. Enterprise’s infamous Warp Drive. Although a convenient storytelling tool for propelling the show’s heroes across the cosmos at human time scales, the scientific viability of warp drive travel didn’t exist when creator Gene Roddenberry’s vision first premiered.

In 1994, Mexican mathematician Miguel Alcubierre moved the discussion from science fiction to science fact when he proposed the first mathematically viable warp drive metric. Since then, several other scientists have weighed in, including noted NASA warp drive pioneer Harold G. Sonny White. Still, even the most elegant mathematical solutions for traveling faster than the speed of light have hit roadblocks that prevent their realization, including the use of exotic forms of matter that exist only in theory.

In an email to The Debrief, Dr. Fell explained that superluminal warp drives (meaning faster than light) “have a whole host of fundamental difficulties that have not been solved yet, not even including negative energies that have historically plagued previous solutions.”

The Debrief previously covered the Applied Physics team’s attempt to solve the problem with a physical warp drive capable of approaching the speed of light but not exceeding it. Although that metric has conquered outstanding physics hurdles that have hampered previous models, the AP team said their new paper used a subluminal version of the original Alcubierre metric.

“The Alcubierre metric is used as a proxy for any zero ADM mass solution, meaning any warp drive solution that does not exhibit typical gravitational effects,” Dr. Fell explained.

Any Warp Bubble Traveling Faster than 5% the Speed of Light

In a recent post on Medium, Dr. Loeb said his previous studies confirmed that the distortion of spacetime proposed in the warp drive metric “must perturb the air” when passing through Earth’s atmosphere. The Harvard scientists also noted that those studies showed that such an atmospheric perturbation caused by a relativistic warp drive “would inevitably generate a bright fireball by shocking the air around it.”

In a previous article, AP physicists told The Debrief that a well-known 2006 UAP sighting in Chicago that included a hole “punched in the clouds” also fits with predictions of warp drive interactions with Earth’s atmosphere.

To follow up on his latest proposal, Loeb and Fell conducted detailed hydrodynamical simulations of the airflow around warp bubbles encasing theoretical spacecraft. In warp drive models, a warp bubble encases the craft in an area of stable space, keeping it completely still as the drive propels toward its destination by warping space itself. This effect is what gives the drive its name.

After running the numbers, Loeb and Fell determined that the heated air around the warp bubble would reach 220 billion degrees Kelvin if the spacecraft was traveling fast enough. Critically, the team calculated the effects of such craft passing through the atmosphere “at a fraction of the speed of light.”

“Any warp bubble traveling faster than 5% the speed of light through the atmosphere will generate optical signatures qualitatively the same as those presented in our paper,” Fell told The Debrief, before adding “slower than that, and the optical signature has a different physical origin.”

Loeb said the calculation suggests that an “aircraft-scale” spacetime (warp) bubble moving at the right velocities would produce luminosities exceeding one terawatt. For comparison, the AP scientist noted that this amount of energy is roughly one-tenth of global electric power consumption.

A “Brilliant Fireball” Detectable at Great Distances

When describing how this high-energy atmospheric interaction would appear to a ground observer, Loeb said, “It should be easy to detect such a brilliant fireball at great distances.”

For example, Loeb explained that any observer would witness two distinct signals suggesting that a warp drive-propelled craft has entered the atmosphere. The first would be a direct, high-energy burst of radiation emanating from the shock zone. Next, a wave of extremely energetic photons would get absorbed by the thicker lower atmosphere. Loeb said this “extreme” energy ends up “reradiated” as light in the visible ultraviolet (UV) spectrum.

“This will manifest itself as a bright atmospheric glow directly below the shock zone,” the Harvard scientist explained.

The study authors also noted that some fireballs would be larger than others. In the right scenario, Loeb suggested that the atmospheric glow caused by a warp drive could “completely dominate the surface solar flux by orders of magnitude.” This means it would be the brightest object in the sky even during daytime.

Conversely, the Applied Physics team noted that warp drives moving much more slowly through the atmosphere, including just above the speed of sound, would not be nearly as bright as those moving above 5% the speed of light. Loeb said warp drive craft at rest or moving well below relativistic speeds “would not generate such extreme luminosities.”

Micrometer-Sized Warp Bubbles as Weapons?

Another intriguing aspect of the study involves the possibility of extremely small warp bubbles interacting with the atmosphere to generate visible light signatures. For example, Loeb suggested that “a micrometer-scale bubble moving at a few times the sound speed at sea-level would result in a modest luminosity of order 1 kilowatt.”

“This slower velocity regime is something we are currently studying,” Fell told The Debrief.

When asked what practical benefits a micrometer-sized warp bubble seemingly too small to accommodate a full-sized spacecraft might offer, Fell joked that a discussion with “my alien buddies” resulted in some unexpected solutions. This included one potentially ominous possibility and another more fantastical explanation that sounds like something right out of the world of Harry Potter.

The first harrowing solution Fell and his hypothetical “otherworldly” colleagues offered involved using tiny warp drive-enabled craft as weapons. For example, the AP physicist explained, even a microscopic warp bubble would exhibit “tremendous gravitational tidal forces.” Based on their models, Fell told The Debrief that such a micrometer-sized warp bubble “would obliterate almost any material in its path, especially if it’s traveling exceedingly fast.”

“This is a very difficult topic to analyze critically because we don’t really know if superluminal warp travel is allowed by the laws of physics,” Fell also told The Debrief. “Would it create observable signatures? Almost certainly. Would any human still be alive to record the measurement? Probably not.”

The Interior of a Tiny Warp Bubble—Harry Potter’s “Weasley Tent”?

Since any plan that would likely annihilate the Earth “wouldn’t be very practical for the aliens,” Fell offered The Debrief an even more fantastical explanation for why our spacefaring visitors may want to engage a micrometer-sized warp bubble, which scientists call the Van Den Broeck warp drive.

As Fell explained, general relativity allows the surface area of a theoretical warp bubble to be microscopically small, “while the interior volume may be as large as you want.”

“I always think of the Weasley tent at the Quidditch World Cup in the 4th Harry Potter book (Harry Potter and the Goblet of Fire),” the AP physicist told The Debrief. “The outside looks like a normal camping tent, but the inside is this great big room.”

Surprisingly, such fantasy world solutions to practical scientific problems are theoretically achievable within general relativity. As a result, Fell added, if the models were correct and such a warp bubble was viable, relativity as we understand it “provides an avenue for microscopic warp bubbles that can house great big ships or other cargo.”

“The applications are really endless for that,” he added.

Connecting Warp Drive Physics with UAP Sightings

When discussing the connection between their findings and the accounts of Unidentified Aerial Phenomena (UAP) chronicled in recent Pentagon document releases, Loeb pointed to a series of ‘puzzling’ orbs “mentioned explicitly in a reliable report dated June 5, 2026.”

According to Loeb, that report, signed by Dr. Jon Kosloski, director of the All-Domain Anomaly Resolution Office (AARO) in the Pentagon, describes “an orange ‘mother’ orb launching smaller red orbs.” Loeb’s retelling of Dr. Kosloski’s account also notes that “40% of the phenomena during the reported event lack a reasonable explanation and remain unresolved.”

Although some UAP reports describe physical craft, researchers have often noted that the largest category involves glowing light or orbs. Although Loeb did not suggest all or any sightings were alien craft, the study’s author noted that warp-drive physics supports the idea that some of these reports could be explained by advanced propulsion technology.

“Could some of the reported orbs be slow warp bubbles?” Loeb asked. “There is one way to find out: by studying them experimentally.”

Dr. Fell agreed, telling The Debrief that “the important thing is that purported UAP observations can be critically examined through the laws of physics, as we know them today.”

“If there really are intelligent beings visiting our Earth, how did they get here?” he asked. “What was their mode of transport? If such a spacefaring vehicle entered our atmosphere, what would it look like?”

While neither author suggested that their mathematical solution settles the debate about aliens or alien craft visiting Earth, Fell said their paper “places observational constraints on these questions and narrows the possibilities.”

AP founder Gianni Martire similarly told The Debrief that his team’s paper does not prove warp drive or alien life. However, the enthusiastic scientist did note that the mathematics makes it possible that science “may simply be catching up to UFO lore that has existed for hundreds of years.”

“It’s possible E.T has been flashing his headlights at us along, not by choice,” Martire said.

The study “Radiative Signatures from Warp Drives Traveling Through the Earth’s Atmosphere” is available on the preprint server, arXiv.

Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org.

Using the same basic physics based on the familiar hollow tone produced by blowing across an empty bottle, researchers in Switzerland have developed a sound-powered propulsion system that can steer microrobots and even lift tiny machines.

In a new study published in Science Advances, engineers at the Swiss Federal Institute of Technology Lausanne (EPFL) demonstrated that 3D-printed cavities known as Helmholtz resonators can convert sound into directed jets of air and usable thrust.

The researchers built devices ranging from centimeters down to micrometers, used sound to propel and steer tiny boats, and created two microscopic flying machines—one microrobot lifted directly by acoustic thrust and another using rapidly spinning rotor blades. One version generated nearly five times its own weight in thrust, while another spun at up to 13,000 revolutions per minute to produce aerodynamic thrust.

The work points to a new way to power small robots without conventional motors, while also exposing the considerable engineering problems that remain before such machines can operate autonomously.

“While acoustic resonators have been extensively studied in liquids for the realization of untethered microrobots, their implementation in air remains largely unexplored,” researchers write. “The actuation scheme is compatible with even further miniaturization, pushing the boundaries of robotics and aeronautics.”

The idea behind the technology is surprisingly familiar. Blow across the top of an empty bottle and you hear a deep, hollow note created as the air trapped inside begins to vibrate.

Known as Helmholtz resonance, the effect happens because the air inside the bottle and its narrow opening behave somewhat like a mass attached to a spring. When sound at the right frequency excites a specially designed resonator, those vibrations become much stronger, forcing air rapidly through the opening. The resulting airflow can form a directional jet powerful enough to generate thrust.

The researchers set out to harness the same physics behind Helmholtz resonance as an unconventional propulsion method for microrobots.

The researchers designed tiny cavities that take advantage of the same principle. When sound hits one of these resonators at just the right frequency, the air in its narrow neck begins moving rapidly back and forth.

Because that airflow is slightly uneven as it enters and exits, it creates a small but focused jet of air. That jet produces thrust, giving the resonator enough force to help move or even lift a microrobot.

The team 3D-printed resonators ranging from centimeter to micrometer scales, designing them to respond to frequencies between roughly 200 hertz and 40 kilohertz. Experiments showed that larger cavities generally produced greater thrust, while the geometry and thickness of the resonator’s neck played a particularly important role in determining performance.

Importantly, researchers could tune different resonators to different frequencies. That means sound does more than supply power; frequency can effectively serve as a control signal.

The researchers demonstrated the concept using miniature boats equipped with acoustic resonators. One early prototype carried a resonator tuned to 1.2 kilohertz and moved only when exposed to sound at that frequency.

More advanced versions used separate resonators for propulsion and steering, allowing the researchers to guide a boat around obstacles remotely and along a figure-eight course with a mean tracking error of just 5.70 millimeters.

The team also showed that an external speaker is not always necessary. By attaching small vibration transducers directly to resonators, they could send sound through the robot’s structure itself.

This approach allowed the researchers to build a fully integrated boat equipped with its own battery, control electronics, and acoustic transducers. Bluetooth commands activated resonators tuned for propulsion and steering, with a total communication latency of about 30 milliseconds. The boat successfully traced the letters “EPFL,” navigated past obstacles, and could be steered back on course after researchers deliberately disturbed it by blowing air or physically pushing it.

However, shrinking the technology into flying microrobots provided the study’s most striking demonstration.

One microflier consisted of three microscopic resonators operating at 40 kilohertz and weighed only about 150 micrograms. Focused ultrasound caused each resonator to eject a tiny jet of air downward. Together, the three produced a thrust-to-weight ratio of approximately 4.9. The machine accelerated upward, climbed roughly 12 millimeters before settling around seven millimeters above its starting position.

A second design took a different approach. Instead of pointing the acoustic jets downward, the researchers used them to spin a rotor fitted with tiny aerodynamic blades. The entire aircraft weighed 184 micrograms.

Once exposed to ultrasound, the rotor accelerated to approximately 13,000 rpm. Its blades generated enough aerodynamic thrust for takeoff before settling to roughly 6,500 rpm while hovering.

Turning the device upside down prevented it from ascending, helping confirm that aerodynamic thrust, rather than acoustic radiation pressure alone, enabled flight.

Researchers demonstrated unconstrained flight with both microrobot designs. The direct-thrust version climbed rapidly but sometimes flipped in the air. The spinning version was more stable, apparently because its swift rotation provided a gyroscopic stabilizing effect similar to that found in helicopters and spinning discs.

Ultimately, the experiments remain proof-of-concept demonstrations rather than prototypes of free-ranging autonomous microrobots. Airborne propulsion requires external acoustic hardware capable of keeping a sufficiently strong sound field focused on a tiny moving object. That essentially limits the robot’s operating area. Putting the acoustic source onboard offers greater autonomy but might significantly increase the robot’s weight.

The current flying system also operates at a single 40-kilohertz frequency, restricting how independently its resonators can be controlled. The researchers suggest future multifrequency ultrasonic arrays could selectively activate different resonators, allowing small aircraft to steer and coordinate their movement through sound alone.

Further miniaturization is technically possible. Modern 3D nanoprinting can fabricate structures with resolutions around 700 nanometers, possibly allowing resonators only several micrometers across. However, at those scales, viscous forces become increasingly important and may dramatically reduce thrust, meaning simply shrinking the existing design may eventually stop working.

Still, the wider concept could go beyond flying machines. Researchers envision flexible structures containing many differently tuned resonators that can bend, vibrate, or change shape depending on the applied sound frequency, possibly resulting in shape-morphing microrobots and mechanical metamaterials.

“Our work extends the concept of acoustic manipulation toward active propulsion by harnessing cavity resonance to generate directional thrust and controlled motion,” the researchers write. “This approach broadens the scope of airborne acoustic actuation toward small-scale robots capable of autonomous operation in open environments.”

The recent study, “Acoustic Resonators as Wireless Actuators in Air for Small-Scale Robots,” was published in Science Advances. 

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com