A new theory for the origin of the universe proposed by scholars at the University of Padua, University of Barcelona, and University of Pisa, redefines the first few moments of existence and decouples inflation from traditional cosmological models.

The authors claim their approach relies less on speculation than the standard theory of inflation, minimizing dependence on unobserved phenomena. By grounding their framework in quantum physics, the researchers present an almost scale-invariant view of the universe and its expansion.

The Inflationary Paradigm

Astronomers generally agree that the universe underwent a sudden and rapid expansion following the Big Bang. This theory helps explain why the universe appears isotropic and largely homogeneous on a large scale, while still containing scattered, inhomogeneous structures such as galaxies. So far, this inflationary model has been the most successful explanation for how the universe arrived at its present state.

However, the researchers identify two key issues with the standard inflation model. First, it heavily depends on theoretical elements that have never been directly observed. Chief among these is the hypothesized inflaton scalar field—believed to drive inflation—which remains unconfirmed despite decades of investigation.

Second, the model’s flexibility allows for many adjustable parameters, raising concerns among some scientists that it functions more as a post-hoc fit to data than as a truly predictive framework.

Changing Parameters

The new model aims to resolve these concerns by using a single energy scale to generate observable predictions. It begins with de Sitter space-time—a vacuum model of the universe characterized by accelerating expansion driven by dark energy—and builds from there using a quantum physics framework.

Instead of invoking an inflaton field, the model relies on quantum gravitational waves, or gravitons, which are described as quantum oscillations of space-time. These fluctuations seed tiny density differences, setting off a cascade of effects that ultimately lead to the formation of stars, planets, and galaxies. As these ripples evolve nonlinearly, they interact and increase in complexity, producing patterns that can be tested against observational data.

A New Model of The Universe

Offering a fundamentally different view of inflation, the team’s model makes room for scenarios in which inflation may not exist at all. In doing so, it separates the concept of inflation from specific cosmological models. Whether the model holds up will depend on future comparisons with empirical data.

“Understanding the origin of the Universe is not just a philosophical pursuit—it helps us answer fundamental questions about who we are and where everything comes from,” the authors say. “This new proposal offers a simple yet powerful framework. It delivers clear predictions that can be confirmed or ruled out by future observations—such as the measurement of the amplitude of primordial gravitational waves and statistical studies of cosmic structure.”

“Moreover, it shows that no speculative ingredients are needed to explain the cosmos, just a deep understanding of gravity and quantum physics. This model could mark a new chapter in how we think about the birth of the Universe,” the authors conclude.

The paper, “Inflation Without an Inflaton,” appeared on July 8, 2025, in Physical Review Research.

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.

Scientists say they’ve finally solved the mystery behind what happens just before lightning strikes.

While famous inventor and U.S. Founding Father Benjamin Franklin discovered the connection between lightning and electricity back in 1752, experts still had not fully understood the journey from the cloud to the ground more than 270 years later.

“Our findings provide the first precise, quantitative explanation for how lightning initiates in nature,” Victor Pasko, a professor of electrical engineering in the Penn State School of Electrical Engineering and Computer Science, said in a statement announcing the findings. “It connects the dots between X-rays, electric fields and the physics of electron avalanches.”

So, what’s the deal with the atmospheric processes that trigger the giant, explosive sparks of electricity that can heat the air to a temperature five times hotter than the surface of the sun?

According to Pasko and his team, the powerful chain reaction works similarly to an invisible pinball machine. Inside the storm clouds, strong electric fields speed up electrons that crash into molecules, such as nitrogen and oxygen. The reactions produce electromagnetic radiation commonly known as X-rays, as well as even more electrons and high-energy photons. Photons are the fundamental particles that make up light. After this, the lightning bolts are born.

Lightning can heat the atmosphere to five times as hot as the surface of the sun. That’s some 50,000 degrees Fahrenheit (AFP via Getty Images)

Atmospheric scientists knew how charged particles react within clouds. Protons rise and electrons descend toward the ground, resulting in a positive electric charge building on the ground. When that positive charge “reaches out” to the approaching negative charge and the channels connect, the electrical transfer is what we see as lightning, according to the National Oceanic and Atmospheric Administration.

To reach these new conclusions, the international authors used mathematical modeling, simulating the physical conditions in which a lightning bolt is likely to originate.

“We explained how photoelectric events occur, what conditions need to be in thunderclouds to initiate the cascade of electrons, and what is causing the wide variety of radio signals that we observe in clouds all prior to a lightning strike,” Zaid Pervez, a doctoral student in electrical engineering, said. “To confirm our explanation on lightning initiation, I compared our results to previous modeling, observation studies and my own work on a type of lightning called compact intercloud discharges, which usually occur in small, localized regions in thunderclouds.”

Victor Pasko, left, professor of electrical engineering in the Penn State School of Electrical Engineering and Computer Science, and Zaid Pervez, a doctoral student in electrical engineering, uncovered the chain reaction that triggers lightning. They also examined what is known as ‘dark lightning’ (Caleb Craig / Penn State)

They also sought to explain observations of what is known as “dark lightning” or a terrestrial gamma-ray flash.

The invisible X-ray bursts are comprised of the flashes, which are produced in our atmosphere. They’re often produced without flashes of light and radio bursts, which are familiar hallmarks of lightning during stormy weather. The researchers wanted to know why.

“In our modeling, the high-energy X-rays produced by relativistic electron avalanches generate new seed electrons driven by the photoelectric effect in air, rapidly amplifying these avalanches,” Pasko said.

“In addition to being produced in very compact volumes, this runaway chain reaction can occur with highly variable strength, often leading to detectable levels of X-rays, while accompanied by very weak optical and radio emissions. This explains why these gamma-ray flashes can emerge from source regions that appear optically dim and radio silent.”

The international study was published Monday in the Journal of Geophysical Research.

Penn State University scientists exploring the longstanding mystery of how atmospheric dynamics within thunderclouds create powerful lightning strikes, believe they have identified a perfect storm of X-rays, electric fields, and electron avalanches preceding the phenomenon that eventually gives birth to a lightning bolt.

While researchers have long understood the basic science of lightning strikes, the Penn St. team said this is the first study of the “perplexing mystery” to reveal the powerful chain reaction that triggers the event while also accounting for gamma ray bursts and light flashes that often accompany lightning-generating thunderstorms.

“Our findings provide the first precise, quantitative explanation for how lightning initiates in nature,” explained Victor Pasko, a professor of electrical engineering in the Penn State School of Electrical Engineering and Computer Science and the study’s leader. “It connects the dots between X-rays, electric fields, and the physics of electron avalanches.”

To decode lightning strikes, Pasko and colleagues first employed computer models designed to simulate photoelectric phenomena within the Earth’s atmosphere. The team’s models approximated the electrical environment preceding lightning strikes by simulating the seeding of the atmosphere with “relativistic energy” electrons generated by cosmic rays coming from outer space. According to the study authors, these electrons multiply within the electric fields of thunderstorms by colliding with molecules, such as nitrogen and oxygen, present within storm clouds. After these collisions accumulate enough energy, the clouds can emit brief, high-energy photon bursts detectable by ground-based sensors.

Known as a gamma ray flash, the team says this high-energy event preceding lightning strikes “comprises the invisible, naturally occurring bursts of X-rays and accompanying radio emissions” often seen during lightning strikes. By using advanced simulation models to approximate the conditions observed in the field, Pasko said his team was able to offer a previously unavailable “complete explanation” for the detection of X-rays and radio emissions within thunderclouds.

“We demonstrated how electrons, accelerated by strong electric fields in thunderclouds, produce X-rays as they collide with air molecules like nitrogen and oxygen, and create an avalanche of electrons that produce high-energy photons that initiate lightning,” the professor explained.

After completing their computer model, electrical engineering doctoral student Zaid Pervez merged it with field observations made by previous study efforts. By incorporating real-world sensor data captured by ground-based sensors, satellites, and high-altitude spy planes, the team created the most accurate and detailed model of the conditions within thunderclouds. Pervez said this model explained how these photoelectric events occur, the thundercloud conditions necessary to initiate an electron cascade, and the cause of the “wide variety” of radio signals often observed in clouds prior to a lightning strike.

To confirm their findings, Pervez compared them with previous modeling, observational studies, and “my own work” on intercloud discharges, a type of compact lightning that usually occurs in smaller, localized regions within thunderclouds. Along with confirming their findings on the mysterious origin of lightning strikes, the team noted that this analysis also accounted for the terrestrial gamma-ray flashes that can occur during lightning storms, whether or not accompanied by radio bursts or flashes of light.

“In our modeling, the high-energy X-rays produced by relativistic electron avalanches generate new seed electrons driven by the photoelectric effect in air, rapidly amplifying these avalanches,” Pasko said. “In addition to being produced in very compact volumes, this runaway chain reaction can occur with highly variable strength, often leading to detectable levels of X-rays, while accompanied by very weak optical and radio emissions.”

The researcher said this chain reaction likely explains why gamma-ray flashes can “emerge from source regions that appear optically dim and radio silent,” during a lightning storm.

The study “Photoelectric Effect in Air Explains Lightning Initiation and Terrestrial Gamma Ray Flashes” was published in the Journal of Geophysical Research.

The chase

From mid-May through the end of June, ICECHIP storm chasers traveled across the Front Range of the Rockies and the central Plains, sometimes riding in vehicles armored against falling ice. They launched drones, released weather balloons and set up mobile doppler radars — all techniques honed by tornado chasers.

As one group positioned mobile doppler radars to intercept the storm at close range, other researchers were responsible for releasing weather balloons nearby or setting out sensors to measure the size and velocity of a hail strike.

During some storms, researchers released hundreds of pingpong ball-like devices called hailsondes into the tempests’ path to track the life cycle of a hail stone — when it is melting and freezing, and how wind dynamics that lift and drop these chunks of ice affect their growth.

Convective thunderstorms, with big internal updrafts, generate hail by circulating a mix of water and ice crystals into the freezing layers of the upper atmosphere. Hail typically forms at altitudes of 20,000 to 50,000 feet, where temperatures are between minus 22 degrees and 14 degrees Fahrenheit. Those same updrafts sweep hailsondes into the hail-generating parts of each storm.

Hail on a road in Oklahoma.

“If we can track that sensor with time, we’re going to, at least for a couple of these storms, understand the exact path, the exact trajectory that a hailstone takes,” said Victor Gensini, a professor of meteorology at Northern Illinois University and an ICECHIP principal investigator.

In an atmosphere warmed by climate change, “we get a lot more instability,” Gensini said, which researchers think creates stronger updrafts.

Those stronger updrafts can support larger hailstones for more time, which allows balls or discs of ice to gain mass, before gravity sends them racing to the ground.

“It’s kind of like if you take a hair dryer and turn it on its end, it’s pretty easy to balance a pingpong ball, right, in that airstream,” Gensini explained. “But what would you need to balance a softball? You would need a much stronger updraft stream.”

Storm modeling suggests stronger updrafts will increase the frequency of large hail in the future, even as it decreases the likelihood of hail overall. Researchers suspect small hail will decrease because its lower mass means that it will take longer to fall. By the time it’s close to the surface, it has often melted down to water.

“There’s this kind of dichotomy, right, where you get less small hail but more large hail in these warmer atmospheres that have very strong updrafts,” Gensini said.

During their field campaign, the researchers amassed a collection of more than 10,000 hailstones in chests of dry ice to try to determine if their computer models are getting the dynamics of hail growth right.

Hail is measured. ICECHIP / F.A.R.M.

“The hail record is kind of messy,” Gensini said of previous data, adding that observers have recorded more 2-, 3- and 4-inch hailstones, but it’s not clear if that’s because more people are chasing and finding big hail or because the atmosphere is producing more of it.

Gensini said the new measurements will help researchers compare what is happening in the air to what they’re finding on the ground, which should improve hail forecasts and mitigate economic losses.

In many of the areas where ICECHIP is working, there’s a lot of agriculture, according to Karen Kosiba, an atmospheric scientist with the University of Illinois Flexible Array of Radars and Mesonets team who is also working with ICECHIP.

“It affects their crops, their machinery, getting stuff into shelter,” she said. “There’s a lot of economic ties to the weather.”

Columbia University engineers have invented an “extreme” chip that can survive the unusually harsh environment of the CERN Large Hadron Collider (LHC) during high-energy experiments exploring fundamental questions about the universe, such as the LHC’s 2012 discovery of the previously theoretical Higgs boson.

Unlike commercially made computer chip designs, which typically fail under the bombardment of radiation emitted when opposing, near-light-speed particles are coaxed to collide in the multi-billion-dollar, 17-mile-long facility. The one-of-a-kind Columbia chip can maintain data and logic integrity during the facility’s harshest experiments.

The team behind the extreme chip’s creation said adding a ruggedized processor that can survive in this environment could open previously unavailable avenues of research for physicists probing the nature of the smallest particles that make up the very fabric of the universe.

“The next discoveries made with the LHC will be triggered by one Columbia chip and measured by another,” explained Peter Kinget, professor of Electrical Engineering at Columbia Engineering and the lead author of the study detailing the team’s work.

Because scientific experiments often require specialized tools, sensors, environments, and other unique pieces of equipment, researchers are often required to adapt more widely available components to meet their needs. In more extreme circumstances, engineers are even forced to manufacture customized, bespoke tools and components.

According to Kinget, when the market is as small as the one for ruggedized processors capable of surviving in a particle supercollider, even a component as widely available as a computer chip may not exist in such a diverse array of styles.

“Industry just couldn’t justify the effort,” the professor said. “So, academia had to step in.”

For the highest-energy experiments, the team aimed to capture the electrical signals generated during LHC particle collisions and convert them into digital signals that could be quantified and analyzed. To achieve this, they explored a category of devices known as analog-to-digital converters, or ADCs. In the facility’s ATLAS detector, these electrical pulses are currently measured by a liquid argon calorimeter, which uses a massive vat filled with ultra-cold argon gas. Although costly and complex to operate, the calorimeter is the only way to capture an electronic trace of each particle collision in the collider’s extreme environment.

Hoping to design a radiation-resistant extreme chip as a cheaper and simpler alternative, the team began by testing off-the-shelf, commercially available ADCs to determine which ones were more resistant to radiation. Rui (Ray) Xu, a Columbia Engineering PhD student who has worked on the project since he was an undergraduate at the University of Texas, said that under conditions like those a chip might experience during a collision at the LHC, the radiation proved to be too intense and the industrial options all “just died.”

“We realized that if we wanted something that worked, we’d have to design it ourselves,” Xu said.

Due to the cost and logistical complications of creating entirely new manufacturing methods from scratch, the Columbia team opted to stay with commercially proven processes that had already been validated by CERN. Next, they designed the layout of their extreme environment chip by using the layout of its internal architecture to minimize radiation damage. The team also supplemented the radiation shielded chip with internal digital systems designed to automatically detect and correct errors in real time

According to the team’s statement, the combination of proven processes and “innovative circuit-level” manufacturing techniques resulted in a one-of-a-kind extreme environment chip capable of withstanding the “unusually severe conditions at LHC” for at least the next ten years.

After recently passing its final tests, the newly designed data acquisition chip will be installed in the LHC during its next upgrade, scheduled to begin in July 2026 and finish sometime around July 2030. Once installed, the team said its ability to precisely digitize collision signals will enable physicists to explore the fabric of reality at previously unattainable scales. Experiments using the extreme chip could include efforts to further explore the enigmatic nature of the elusive Higgs boson and other subatomic particles that comprise the most fundamental aspects of science, utilized by researchers across diverse disciplines.

“The opportunity as an engineer to contribute so directly to fundamental science is what makes this project special,” Xu said.

“These sort(s) of collaborations between physicists and engineers are very important to advancing our ability to explore fundamental questions about the universe,” added John Parsons, professor of physics at Columbia University and leader of the Columbia team working on the ATLAS detector, one of the LHC’s massive instruments.. “Developing state-of-the-art instrumentation is crucial to our success.”

The study “A Radiation-Hard 8-Channel 15-Bit 40-MSPS ADC for the ATLAS Liquid Argon Calorimeter Readout” was published in the IEEE Open Journal of the Solid-State Circuits Society.