In a groundbreaking experiment at CERN, scientists have recreated the fiery plasma jets of distant blazars, shedding light on one of astrophysics’ enduring puzzles: the origin of cosmic magnetic fields and the mystery of vanishing gamma rays. Using the Super Proton Synchrotron, an international team led by the University of Oxford generated high-density plasma ‘fireballs’ that mimic the extreme conditions around supermassive black holes. This simulation, detailed in a study published in the Proceedings of the National Academy of Sciences, challenges long-held assumptions about plasma behavior in the cosmos.

The experiment involved firing protons at speeds close to light into a block of graphite, producing beams of electrons and positrons that replicate blazar jets—colossal streams of plasma ejected from active galactic nuclei. These jets, often spanning thousands of light-years, are among the universe’s most energetic phenomena, emitting gamma rays detectable from billions of light-years away. Yet, observations show fewer high-energy gamma rays reaching Earth than expected, prompting theories about intergalactic magnetic fields deflecting them.

According to Gianluca Gregori, a physics professor at Oxford and the study’s lead author, the lab-created jets remained remarkably stable over distances equivalent to cosmic scales. ‘Our results indicate that plasma instabilities are not the primary culprit for the missing gamma rays,’ Gregori told ScienceDaily in a recent interview. Instead, the data bolsters the hypothesis that faint magnetic fields, possibly remnants from the Big Bang, permeate intergalactic space and scatter these rays.

Simulating the Unseen: From Particle Accelerators to Cosmic Jets

The Super Proton Synchrotron (SPS), a key component of CERN’s accelerator complex, was pivotal in this feat. Typically used to inject particles into the Large Hadron Collider, the SPS was repurposed for the HiRadMat facility, where intense proton beams smash into targets to generate secondary particles. In this case, the collisions produced electron-positron pairs at densities and energies mirroring those in blazar environments, as reported by Interesting Engineering.

This isn’t the first time CERN has ventured into astrophysical simulations. Previous experiments at the HiRadMat facility have explored black hole jets and neutron star emissions, but this marks the world-first creation of such plasma fireballs, per a CERN press release. The stability observed—jets propagating without the expected kink instabilities—contradicts models predicting rapid disruption, suggesting that external factors like magnetic fields play a larger role in cosmic ray deflection.

High-energy astrophysicists have long grappled with the ‘blazar paradox.’ Blazars, a subclass of active galactic nuclei with jets pointed toward Earth, should flood our detectors with gamma rays above 100 GeV. Yet, telescopes like NASA’s Fermi Gamma-ray Space Telescope observe a shortfall, as noted in a 2013 ScienceDaily article on distant blazar PKS 1424+240. The Oxford-led team’s findings, published November 3, 2025, in PNAS, provide empirical evidence that weak intergalactic magnetic fields—on the order of 10^-16 Gauss—could be responsible.

Unraveling Magnetic Relics: Echoes of the Early Universe

These primordial magnetic fields, theorized to have originated during cosmic inflation or phase transitions shortly after the Big Bang, are notoriously difficult to detect directly. The CERN experiment offers indirect validation by ruling out alternative explanations. ‘The data strengthens the idea of ancient intergalactic magnetic fields, possibly from the Universe’s earliest moments,’ states the ScienceDaily summary of the study.

Collaborators from institutions including the Max Planck Institute and the University of Rochester contributed to scaling lab results to cosmic proportions. Using advanced diagnostics like laser probes and magnetic sensors, the team measured jet stability over 10 centimeters—equivalent to parsec-scale distances in space when adjusted for relativistic effects. Phys.org reported that this scaling confirms the jets’ resilience, implying that magnetic deflection is the key to the gamma-ray deficit.

Beyond blazars, these findings have implications for understanding cosmic ray propagation and galaxy formation. Magnetic fields influence star formation and galactic dynamics, and relics from the early universe could seed the stronger fields observed in galaxies today. As Brian Reville from the Max Planck Institute for Nuclear Physics explained in an EurekAlert! release, ‘This experiment bridges laboratory plasma physics with high-energy astrophysics, offering a new window into unresolved questions.’

Technological Triumphs: Behind the Scenes at CERN’s HiRadMat

The HiRadMat facility, operational since 2012, is designed for extreme material testing under high-radiation conditions. For this study, researchers upgraded the setup with tungsten shielding and precision diagnostics to handle the intense particle fluxes. Posts on X (formerly Twitter) from CERN highlight the facility’s role in ‘bringing black hole jets down to Earth,’ with a June 2024 update noting the production of relativistic electron-positron pairs mimicking black hole vicinities.

Challenges abounded: generating sufficient pair density required proton bunches of up to 10^11 particles, pushing the SPS to its limits. Safety protocols, including beam dumps capable of absorbing energies from 14 to 450 GeV, were crucial, as detailed in CERN’s 2023 updates on X about SPS upgrades. The experiment’s success relied on international funding, including from the European Research Council, underscoring the collaborative nature of modern particle physics.

Industry insiders note that such simulations could accelerate advancements in fusion energy and materials science. Plasma stability insights from this work, as covered by Space.com, might inform tokamak designs for controlled fusion, where similar instabilities plague confinement.

Broader Impacts: From Gamma Rays to Galactic Evolution

The missing gamma-ray puzzle ties into larger questions about dark matter and cosmic structure. If intergalactic magnetic fields are indeed primordial, they could influence the distribution of cosmic voids and filaments, as explored in a 2019 NASA/ADS paper on synchrotron proton blazar models. The CERN results, by excluding plasma-driven dissipation, shift focus to these fields as potential probes of physics beyond the Standard Model.

Recent news on X from users like Interesting Engineering emphasizes the ‘world-first’ aspect, with posts garnering thousands of views. A November 5, 2025, tweet describes the fireballs as a step toward solving ‘a long-standing cosmic puzzle,’ aligning with reports from Gadgets360 on ancient magnetic relics.

Looking ahead, the team plans follow-up experiments to directly measure magnetic field effects in lab plasmas. Gregori hinted at potential integrations with upcoming facilities like the Facility for Antiproton and Ion Research (FAIR) in Germany, promising even denser simulations. As astrophysics increasingly intersects with particle physics, CERN’s fireballs may illuminate not just hidden magnetism, but the very fabric of the universe.

Evolving Paradigms in High-Energy Astrophysics

Traditional blazar models, such as those in a 2015 ADS paper on the blazar paradigm, assume synchrotron emission from relativistic electrons, with inverse Compton scattering producing gamma rays. The CERN study challenges extensions involving proton acceleration, as in a 2003 NASA/ADS work on BL Lac objects, by highlighting external magnetic influences.

Critics argue that lab scales may not fully capture cosmic complexities, like turbulence over vast distances. However, the team’s rigorous scaling laws, validated through simulations, address these concerns. ‘This is a pivotal step in experimental astrophysics,’ said co-author Jens Osterhoff in a Phys.org interview.

Ultimately, these plasma fireballs represent a fusion of disciplines, from accelerator technology to theoretical cosmology. As detectors like the Cherenkov Telescope Array come online, combining ground-based observations with lab data could finally map the universe’s magnetic landscape, revealing secrets etched in the void since time’s dawn.