For a few microseconds after the Big Bang, the universe was filled with an unusual state of matter. At temperatures reaching trillions of degrees, quarks and gluons moved freely in a dense, hot fluid known as quark-gluon plasma. As the universe expanded and cooled, these particles began combining to form protons and neutrons, the building blocks of ordinary matter.

Physicists can recreate this extreme environment today by colliding heavy atomic nuclei at nearly the speed of light inside particle accelerators. The collisions produce tiny droplets of quark-gluon plasma, each lasting only an extraordinarily brief period before breaking apart. Studying what happens inside these droplets is difficult. They are too small and short-lived for scientists to examine directly. Instead, researchers look at how other particles behave as they pass through the plasma. Their movements can reveal details about the fluid’s internal properties.

A study by physicists at the Massachusetts Institute of Technology (MIT) and the University of California, Santa Barbara (UCSB), has developed a new theoretical approach to this problem. Published in Physical Review Letters, the research examines how heavy subatomic particles respond to the forces exerted by a fluid when travelling at speeds close to that of light. The work extends a principle that physicists have relied on for more than a century: Albert Einstein’s explanation of Brownian motion.

The Problem with Einstein’s Explanation

In 1827, botanist Robert Brown noticed that pollen grains suspended in water moved continuously, even when the water appeared undisturbed. The movement was random, with the particles changing direction as though they were being pushed by invisible forces. Einstein explained this phenomenon in a 1905 paper. He showed that the apparently random movement resulted from collisions with the atoms and molecules in the surrounding fluid. These microscopic particles constantly strike a larger suspended particle, producing small, unpredictable changes in its motion.

Two effects determine how the particle moves. The fluid exerts drag, slowing it down, while microscopic collisions keep pushing it in different directions. The relationship between these forces can reveal information about the fluid’s temperature and microscopic composition. Scientists later applied this framework to a range of fluids, including quark-gluon plasma. However, the original theory was developed for particles moving at relatively low speeds. Heavy quarks travelling through an extremely hot plasma can move close to the speed of light, where the familiar relationship between drag and random fluctuations becomes inadequate.

Physicists have been aware of this limitation for about 20 years. MIT graduate researcher Jean Du Plessis and Bruno Scheihing-Hitschfeld of UCSB have now worked out a framework that accounts for the unusual behaviour of particles under these conditions.

When a Particle Receives an Unusually Large Kick

The researchers calculated the forces a heavy quark would experience while travelling through a fluid at relativistic speeds. They began with a simplified model in which the particle moved through a gas of weakly interacting quarks and gluons. This made it possible to calculate how the strong nuclear force would affect its momentum.

The team then examined the probability of different changes in the quark’s momentum. In the conventional Brownian motion model, small changes are common, while extremely large ones are rare. The resulting probability distribution takes the shape of a bell curve, with the most extreme movements appearing at its two ends. The calculations for relativistic heavy quarks produced a different pattern.

For smaller changes in momentum, the distribution still resembled a bell curve. At the outer ends, however, it became uneven. Large changes occurred more frequently than the conventional model would predict. A particularly interesting finding was that a large kick slowing the quark down was more likely than an equally large kick pushing it in the opposite direction.

This imbalance is important because it suggests that the movement of heavy quarks carries information that conventional Brownian motion models miss. “How often those large changes occur depends on the microscopic nature of the plasma,” Du Plessis said. Such events could therefore offer researchers another way to investigate what happens inside quark-gluon plasma. The researchers repeated their calculations for plasmas made up of different particles. They found that the same tilted probability distribution appeared across these different conditions. They also identified the mathematical pattern in an earlier calculation involving a strongly interacting plasma, despite the differences in the underlying microscopic physics. The finding points to a potentially universal feature of how relativistic particles interact with fluids.

Reading the Properties of the Early Universe

Quark-gluon plasma is known to behave more like a liquid than an ordinary gas. Experiments have shown that it flows with remarkably little internal resistance, suggesting that its constituent quarks and gluons interact strongly.

The new framework could help physicists investigate these interactions by examining how heavy quarks lose momentum as they travel through the plasma. Researchers can compare the theoretical predictions with measurements from particle accelerator experiments and use the differences to refine their understanding of the fluid. Du Plessis believes the primordial quark-gluon plasma was more strongly interacting than a simple Brownian motion model might suggest. Its behaviour, he says, was closer to that of a liquid than a gas.

The calculations do not directly tell scientists what the universe’s first fluid looked like. They offer a more precise way to interpret the behaviour of particles produced in laboratory collisions, bringing researchers closer to understanding the properties of matter during the universe’s earliest moments. The research received support from the US Department of Energy’s Office of Nuclear Physics, the US National Science Foundation and the Simons Foundation.

Researchers at the Massachusetts Institute of Technology (MIT) have developed an origami-inspired construction method that could enable the fabrication of lightweight, rigid structures using less material and simpler assembly techniques. The approach could eventually be used for emergency shelters, architectural components and lightweight aerospace parts.

The modular system uses components cut from flat sheets of material, folded into shape and connected to form three-dimensional structural shells. According to MIT, simulations indicate that the structures can be approximately 3.5 times stiffer than those produced using some other structural origami techniques, while requiring only about two-thirds as much material.The research was announced by MIT on October 27 and published in the International Journal of Solids and Structures.

Building structures through folding

The researchers drew inspiration from geometric patterns developed by artist and scientist Ron Resch in the 1960s. Unlike methods that fold a single sheet into a complete structure, the new approach uses individually fabricated components that are folded and connected to create a larger framework.

Alfonso Parra Rubio, a graduate student at MIT’s Center for Bits and Atoms and lead author of the study, developed a method for combining two tripod-shaped units into a rigid building block. These blocks can be interconnected to form a network of beams that creates a lightweight structural shell.

To simplify the design process, the team developed computational software that automatically generates components according to the intended structure. The software checks whether individual units can be folded before combining them into the final design.

The resulting files can be sent to computer-controlled cutting equipment to manufacture components from flat sheets of material, including aluminium. Workers can then fold and assemble the units using basic hand tools, without requiring large-scale welding equipment.

Demonstration at architectural scale

To demonstrate the method’s scalability, the researchers constructed a 23-foot folded-aluminium sculpture that was installed in the atrium of the Boston Public Library. According to MIT, a team without professional construction experience assembled the structure in a matter of days.

The researchers say the modular design simplifies assembly because the components are engineered to fit into their intended positions as the structure takes shape.

Representational image.Image credit:Pexels

However, the reported stiffness improvements are based on simulations comparing the method with other origami-based systems. Further testing will be necessary to establish its performance across different materials, loading conditions and real-world construction environments.

Potential applications

One potential application is disaster-relief housing. Flat-packed components could be transported efficiently to areas affected by earthquakes or floods and assembled on site, potentially reducing transportation and construction requirements.

The approach could also be explored for lightweight aerospace components, modular robots, sound-dampening panels and building facades. Its ability to create rigid structural shells without interior support columns could offer additional flexibility in architectural design.

The researchers plan to test the technique in larger architectural structures and investigate more complex component geometries that could improve strength and stiffness. They also intend to develop a more accessible interface for designing structures using the system.

While the method has yet to demonstrate widespread use in buildings, the research illustrates how geometric design and digital manufacturing could offer alternatives for constructing complex structures.

Its practical adoption will depend on factors including durability, manufacturing costs, structural safety and performance under real-world conditions. Nevertheless, the approach presents a potential option for applications where reducing material use and simplifying assembly are priorities.

An international team of researchers from India and Belgium has developed portable particle detectors that could help scientists examine the interiors of mountains, tunnels and historical monuments without damaging them. The technology uses naturally occurring cosmic-ray particles to map variations in the density of objects, offering a potential approach to non-invasive imaging of large structures.

The detectors, developed using glass-based Resistive Plate Chambers (RPCs), achieved a particle-detection efficiency exceeding 95% during testing, according to a report published by Research Matters on October 24, 2026. The findings demonstrate the potential of compact detector systems to investigate dense materials and support future applications in geology, archaeology and infrastructure assessment.

The collaboration includes researchers from India’s National Institute of Science Education and Research (NISER), Bhubaneswar, and the Homi Bhabha National Institute (HBNI), alongside researchers from Belgian institutions, including Université catholique de Louvain and the Inter-University Institute for High Energies.

How cosmic rays reveal hidden structures

The technology uses muons, high-energy particles produced when cosmic rays interact with Earth’s atmosphere. These particles continuously reach the Earth’s surface and can penetrate substantial thicknesses of rock, concrete and other materials.

As muons travel through an object, some are absorbed or deflected depending on its density and thickness. By measuring the number and trajectories of particles passing through a structure, researchers can identify variations in internal density and reconstruct images of otherwise inaccessible areas.

The technique, known as muography, is comparable in principle to X-ray imaging, but uses naturally occurring particles instead of an artificial radiation source. It has previously been used to investigate geological formations, including volcanoes, and to explore archaeological structures.

However, conventional muon detectors can be bulky, difficult to transport and challenging to operate in remote locations. The new glass-based detectors aim to address some of these limitations through a compact design and sealed operation, reducing dependence on continuous gas supplies.

Testing the detector system

The researchers developed three glass RPC prototypes using thin glass electrodes separated by gas-filled gaps. When a muon passes through a chamber, it ionises the gas, generating an electrical signal that can be recorded to determine the particle’s position.

Electronic readout systems capture these signals and help reconstruct the trajectories of incoming particles. During testing, the detectors achieved an efficiency exceeding 95%, with a timing resolution of approximately 1.8 nanoseconds, according to the research report.

To examine the system’s ability to detect dense materials, the team conducted an absorption experiment using one prototype. During an open-sky measurement, researchers recorded nearly 55,000 muon tracks. After placing a lead block in the experimental setup, the recorded count fell to 30,894, demonstrating how dense material reduced the number of particles reaching the detector.

Representational image.Image credit:Pexels

The experiment provided proof of principle that the system could measure muon attenuation and support radiographic imaging. However, imaging complex structures such as mountains or monuments requires measurements from multiple directions and further computational reconstruction.

Applications and challenges ahead

Portable muon detectors could eventually help researchers investigate hidden cavities, examine geological formations, inspect tunnels and study the internal structures of historical monuments. Engineers could also explore their application in assessing infrastructure such as dams and bridges, although these uses would require additional testing and validation.

For cultural heritage conservation, muography could offer a valuable alternative where drilling or other invasive investigations risk damaging fragile structures. A 2025 review published in iScience highlighted the technique’s potential as a complementary, non-destructive method for studying cultural heritage objects, while noting that the relatively low flux of naturally occurring muons can require lengthy data-collection periods.

The technology is not yet a universal replacement for existing inspection methods. Its practical application will depend on factors such as spatial resolution, detector size, measurement duration and the complexity of the structure being examined.

The researchers have proposed further improvements, including lighter structural materials, larger detector areas and enhanced readout systems. These developments could make the detectors easier to deploy and improve the quality of reconstructed images.