Bazinga! Physicists crack ‘Big Bang Theory’ problem

Fusion reactors could help shed light on dark matter

University of Cincinnati

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

UC Professor Jure Zupan is a theoretical physicist who studies topics such as dark matter.

view more 

Credit: Joseph Fuqua II

A professor at the University of Cincinnati and his colleagues figured out something two of America’s most famous fictional physicists couldn’t: theoretically how to produce subatomic particles called axions in fusion reactors.

Particle physicists Sheldon Cooper and Leonard Hofstadter, roommates in the CBS sitcom “The Big Bang Theory,” worked on the problem in three episodes of Season 5 but couldn’t crack it.

Now UC physics Professor Jure Zupan and his theoretical physicist co-authors at the Fermi National Laboratory, MIT and Technion–Israel Institute of Technology think they have one solution in a study published in the Journal of High Energy Physics. 

Axions are hypothetical particles that physicists suspect could help explain dark matter. Researchers are interested in dark matter because it helps explain the evolution of the universe after its creation in the Big Bang nearly 14 billion years ago.

Dark matter has never been observed directly, but physicists believe it represents a majority of the mass in the universe that is attributed to matter, while only a fraction is due to normal, visible matter. Dark matter is called dark because unlike normal matter it does not absorb or reflect light.

Nevertheless, physicists have identified its existence through its gravitational effects, modifying motion of galaxies in the universe and stars in the galaxies. One of the main theoretical possibilities for dark matter is that it is a very light particle, the so-called axion. 

In their paper, Zupan and his colleagues considered a fusion reactor powered by deuterium and tritium in a vessel lined by lithium that is being developed in a global collaboration in the south of France. Such a reactor would produce not only energy but potentially also dark sector particles due to a large flux of neutrons that will be created in a fusion reactor.

“Neutrons interact with material in the walls. The resulting nuclear reactions can then create new particles,” he said.

The second way the new particles can get generated is when neutrons bounce off other particles and slow down, releasing energy in a process physicists call bremsstrahlung or “braking radiation.”

The new particles could be axions, or at least axion-like particles. And that’s where the show’s fictional physicists failed, Zupan said.

“The Big Bang Theory” ran from 2007 to 2019 and earned seven Emmys. It remains among the most-watched shows of any streaming service, according to Nielsen.

“The general idea from our paper was discussed in ‘The Big Bang Theory’ years ago, but Sheldon and Leonard couldn’t make it work,” Zupan said.

In one episode, a white board features an equation and diagram that Zupan said describes how axions are generated from the sun. In a subsequent episode, another equation appears on a different board. Below the calculations in a different marker color is an unmistakable sad face — a symbol of failure.

Zupan said Leonard and Sheldon’s equation estimates the likelihood of detecting axions from their proposed fusion reactor compared to the sun — with discouraging results, which explains the sad face.

“The sun is a huge object producing a lot of power. The chance of having new particles produced from the sun that would stream to Earth is larger than having them produced in fusion reactors using the same processes as in the Sun. However, one can still produce them in reactors using a different set of processes,” he said.

The characters in the show never talk about axions or the white boards in the episodes. They’re just an Easter egg for physicists in a show famous for incorporating scientific concepts like Schrodinger’s cat and the Doppler effect into its storylines, along with cameos by Nobel laureates and “Star Trek” alumni alike.

“That’s why it’s fantastic to watch as a scientist,” Zupan said. “There are many layers to the jokes.”

  

University of Cincinnati Profesor Jure Zupan is a theoretical physicist who studies topics such as dark matter.

Credit

Joseph Fuqua II

---

Journal

Journal of High Energy Physics

DOI

10.1007/JHEP10(2025)215 

Article Title

Searching for exotic scalars at fusion reactors

 

DNA floating in air reveals the hidden past of ecosystems

Umea University

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Daniel Svensson and Anna-Mia Johansson take a break from DNA extractions to discuss new results. Both are research engineers at the Department of Ecology, Environment and Geoscience, Umeå University, and co-authors of the study.

view more 

Credit: Photo: Bea Andersson

DNA captured on air filters and stored since the 1960s acts as an ecological time capsule, according to a recent publication in Nature Communications. The findings show that tiny fragments of genetic material can paint a detailed picture of life across the landscape. They also reveal a distinct decline in biodiversity over three decades.

 

All organisms shed cell fragments with DNA to the environment. Now, researchers have performed the largest and most detailed analysis to date of airborne DNA using filters originally used to monitor radioactive fallout.

Air monitoring filters are found at hundreds of sites worldwide. These particular filters come from a station outside Kiruna, in northern Sweden, and have been archived in a basement at the Swedish Defence Research Agency, FOI, since the 1960s. When researcher Per Stenberg learned about the archive about a decade ago, he and his colleague Mats Forsman realised what a goldmine it was.

Week after week, the filters collected DNA from all living things: plants, fungi, insects, microbes, birds, fish, and even large mammals like moose and reindeer. By sequencing the DNA, the research team was, on a weekly basis, able to identify the presence of 2,700 organism groups within several miles of the station, and track how their populations increased or decreased over 34 years.

“It was a stroke of luck that the filters had been kept – and that they were made of a material that preserves DNA. The archive turned out to be a time machine, allowing us to revisit the past and watch an ecosystem changing in almost real time,” says Per Stenberg, lead author of the study conducted by researchers from Umeå University, the Swedish University of Agricultural Sciences, and the Swedish Defence Research Agency.

When the researchers looked at long-term patterns, they saw a clear decline in biodiversity in the area, from the 1970s to the early 2000s. Examples of declining organisms include birch together with wood-associated lichens and fungi. The overall decline cannot be explained by changes in the climate, but rather seems to be linked to human activities such as forest management.

Analyses of airborne DNA have been done before, but this is an entirely new and far more comprehensive approach that spans several decades. The research team used extensive DNA sequencing, machine-learning-based identification of organisms, and air-flow modelling to track the sources of the DNA. Comparisons with traditional field surveys show that the method is reliable both for identifying organisms and for detecting changes in their abundance.

“This work is the result of nine years of intense research and development. I look forward to applying these data, together with ongoing sequencing of additional filters, to a wide range of questions,” says Daniel Svensson, a co-author of the study.

The study shows that existing networks of air-filter stations can be used to monitor biodiversity trends and reconstruct ecosystems in places where baseline data are missing. This is essential for predicting future changes and adapting management and restoration strategies.

“The method can also detect and track genetic variation as well as the presence of invasive species and pathogens,” says Per Stenberg.

Per Stenberg at the site of the air-filter station outside Kiruna in northern Sweden.

Credit

Edvin Karlsson

---

Journal

Nature Communications

DOI

10.1038/s41467-025-67676-7 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Airborne eDNA captures three decades of ecosystem biodiversity

Article Publication Date

18-Dec-2025

 

Studies by Montana State scientists reveal importance of experimentation on greenhouse gas-producing organisms

Montana State University

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

By Diana Setterberg, MSU News Service

BOZEMAN – It’s been known for nearly a century that swarms of single-celled organisms thrive by consuming chemicals from their environments and expelling methane gas as a byproduct. In 2024, researchers in the laboratory of Roland Hatzenpichler, associate professor in the Department of Chemistry and Biochemistry in Montana State University’s College of Letters and Science, published the first-ever descriptions of methane-producing microbes outside the lineage Euryarchaeota, which – in a soon-to-be-published study – they have confirmed to be ubiquitous in the environment.

These methanogens are members of the lineage Thermoproteota within a part of the tree of life called Archaea. Until the journal Nature published the findings from Hatzenpichler’s group last year, scientists believed all methanogens existed in the Euryarchaeota.

Hatzenpichler said scientists are eager to know how much methane thermoproteotal microbes produce because methanogens produce approximately 60% of the world’s methane – a gas 28 times more potent than carbon dioxide in trapping heat in the atmosphere, according to the U.S. Environmental Protection Agency. After the thermoproteotal group was discovered, scientists began preparing genomic models to predict the organisms’ environmental impact. 

But new evidence from Hatzenpichler’s lab, published Dec. 12 in the journal Science Advances, indicates that another newly identified methanogen in the Thermoproteota defies the predictions of those models. MSU researchers hypothesized that the new microbe, a member of the group Methanonezhaarchaeia, would convert carbon dioxide to methane. However, through experimentation on cultures of samples harvested from a Yellowstone National Park hot spring, Hatzenpichler’s former graduate student Anthony Kohtz and current graduate student Sylvia Nupp discovered that the organism grows and produces methane not by feeding on carbon dioxide but on methylated compounds, which are omnipresent in the environment. Both Thermoproteota previously identified at MSU also use compounds such as methanol for growth and survival.

Hatzenpichler said the results of the research cast doubt on the validity of the genomic models and demonstrate the necessity of further experimental study to validate or disprove modeling predictions.

“Our genome predictions say a huge chunk of CO2 is converted to methane, based on a few experiments and the assumption that the results are representative of all of those genomes,” Hatzenpichler said. “But we have historically ignored one group of organisms (Thermoproteota), so we’re ignorant about what is making methane and about the substrates that are converted in the first place. And most researchers don’t actually measure which compounds are converted to methane in the environment. A lot is simply based on assumptions.”

To further bolster foundational knowledge, Hatzenpichler’s group is continuing its research into thermoproteotal methanogens under a four-year, $1 million research grant awarded in September 2024 by the U.S. Department of Energy’s Biological and Environmental Research program. In collaboration with researchers at the DOE’s Joint Genome Institute and Environmental Molecular Sciences Laboratory, the goal is to determine how much methane is generated by a widely distributed group of methanogens within the Thermoproteota – the Methanosuratincola – and to better understand their physiology and biological processes.

Another paper from Hatzenpichler’s lab, recently accepted for publication by the journal Current Opinion in Microbiology, reveals that methanogens belonging to the Thermoproteota live in any environment devoid of oxygen, including landfills, oil reservoirs, rice paddies, wastewater treatment plants and wetlands – not to mention in Yellowstone’s hot springs, where the three lineages identified at MSU were found.

“Experimentally, it’s very demanding, and we probably can’t do it for all the environments we want to study,” said Hatzenpichler, who is also director of MSU’s Thermal Biology Institute. “On a global level, hot springs are completely irrelevant to methane emission, so now we need to go to ecosystems that are more important than hot springs to methane production.”

He said graduate student Nicole Matos Vega, a recent recipient of a Graduate Research Fellowship awarded by the National Science Foundation, has collected and cultured microbes from mangrove swamps in Puerto Rico. She discovered, for still poorly understood reasons, that they are “making a lot of methane.” Hatzenpichler said Matos Vega also will study the methanogens in their native swamps to ensure that they react the same way in the lab as they do in their natural habitat.

Another target ecosystem is wastewater, studies of which have already begun on samples provided by collaborators in Illinois. Graduate student Joelie Van Beek, a new recipient of a NSF EPSCoR Graduate Fellowship, found thermoproteotal organisms living in Bozeman’s wastewater treatment plant, and those may be brought into culture, as well. Hatzenpichler said having the plant nearby will make it easier for his lab to test a number of variables in that ecosystem.

One problem with genomic modeling is it relies on measured levels of compounds found in various environments to predict whether methanogenesis is taking place, Hatzenpichler said. However, he noted that just because the level of a compound is low in a particular environment doesn’t mean that it isn’t important there. Instead, it may be low because the methanogens there are consuming it.

“Genome analysis is very, very powerful, though limited, and experimentation is very demanding,” he said. “The idea with our research is that we will try to understand these ecosystems from all different kinds of angles.”

---

Journal

Science Advances

DOI

10.1126/sciadv.aea093 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Cultivation of Methanonezhaarchaeia, the third class of methanogens within the phylum Thermoproteota

Article Publication Date

12-Dec-2025

Breakthrough of the Year: Renewable energy begins to eclipse fossil fuel-based sources

Summary author: Walter Beckwith

American Association for the Advancement of Science (AAAS)


Science has named the seemingly unstoppable growth of renewable energy worldwide as the 2025 Breakthrough of the Year. Since the Industrial Revolution, humanity has relied on fossil fuels like coal, oil, and gas for energy. Carbon emissions from these finite resources have greatly contributed to accelerated climate warming. However, 2025 marked a significant shift in this paradigm as renewable energy generated from the Sun and wind began to surpass conventional fossil fuel-based energy production in several domains. This year, global renewable energy, led by solar and wind, grew fast enough to cover all the world’s new electricity demand in the first half of the year, and now supplies more electricity than coal worldwide. This transition is being led by China, whose efforts to scale up solar panels, wind turbines, and lithium battery storage have cemented the nation as a global leader in renewable energy production and technology. Elsewhere, small-scale rooftop solar systems – made affordable and widely accessible by China’s manufacturing dominance – are spreading rapidly, particularly across Europe, South Asia, and the Global South, and provide reliable, low-cost energy security for millions. Already, existing renewables have demonstrably slowed the growth of greenhouse emissions in China, hinting at a global turning point in addressing ongoing climate warming. What’s more, further technological innovations in this space, such as more efficient solar cells and battery chemistries, for example, promise to extend the reach and effectiveness of renewable energy. Many obstacles remain, however, including continued widespread coal use, infrastructure bottlenecks, and political resistance in some regions (including the United States). Yet, despite these challenges, this year’s breakthrough suggests that the transition from fossil fuels to clean, renewable energy is not just possible – it’s accelerating – and rapidly becoming the most practical and cost-effective choice.



Podcast: A segment of Science's weekly podcast with Greg Miller, related to this research, will be available on the Science.org podcast landing page after the embargo lifts. Reporters are free to make use of the segments for broadcast purposes and/or quote from them – with appropriate attribution (i.e., cite "Science podcast"). Please note that the file itself should not be posted to any other Web site.

Journal

Science