Scientists uncover puzzling data on cosmic expansion discrepancy

KUALA LUMPUR, 5 OCTOBER 2026 —

Tiny Magnetic Fields From the Big Bang May Hold Key to Universe’s Expansion Mystery, Scientists Say

The discovery, published in a new study, suggests these primordial magnetic fields—far weaker than those on Earth—may have subtly altered the formation of hydrogen in the early universe, leaving an imprint on the cosmic microwave background (CMB) that could explain why estimates of the Hubble constant differ by about 6 km/s/Mpc.

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The Hubble tension has baffled astronomers for years. The universe’s expansion rate, quantified by the Hubble constant, is measured in two primary ways: indirectly through the CMB, the afterglow of the Big Bang, and directly by observing distant supernovae. The two methods yield incompatible results—67 km/s/Mpc (CMB-based) versus 73 km/s/Mpc (supernova-based)—a discrepancy too large to be dismissed as observational error.

The new research builds on earlier theories that primordial magnetic fields, remnants of the universe’s first moments, could have influenced the recombination epoch—when electrons and protons combined to form neutral hydrogen, allowing light to travel freely for the first time. These fields, if strong enough, would have accelerated recombination by clustering charged particles, slightly warping the CMB’s temperature fluctuations.

Using the first full 3D simulations of primordial plasma with embedded magnetic fields, the team—led by Levon Pogosian, Karsten Jedamzik, and Tom Abel—modeled how hydrogen formed under these conditions. Their findings show that such fields, with strengths of roughly 5 to 10 pico-Gauss today, could adjust the CMB’s patterns in a way that aligns the two Hubble constant measurements.

The study’s statistical analysis found a consistent preference for primordial magnetic fields across multiple datasets, though not yet at a definitive level (ranging from 1.5 to three standard deviations). If confirmed, these fields would not only resolve the Hubble tension but also provide a rare glimpse into physics at energies far beyond what particle colliders can probe.

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The implications extend beyond cosmology. Magnetic fields are ubiquitous in the universe—from planets and stars to vast galaxy clusters—but their origins remain poorly understood. The new research suggests that the seeds of these fields may have been sown in the universe’s first split seconds, potentially linking them to fundamental physics, such as inflation or phase transitions in the early cosmos.

The team’s simulations tracked hydrogen formation in unprecedented detail, showing that even minuscule magnetic fields could have left a detectable signature in the CMB. Crucially, the favored field strengths align with independent estimates needed to explain the magnetism observed in galaxies and clusters today.

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For Malaysia and regional readers, while this discovery is primarily of academic interest, it underscores the global collaboration driving cutting-edge physics. The Hubble tension has prompted major investments in telescopes like the James Webb Space Telescope (JWST) and the upcoming Euclid mission, which may provide further data to test these theories.

Locally, institutions such as the National Space Agency (ANGKASA) and universities like the University of Malaya follow such advancements closely, as they inform broader questions about the universe’s fundamental laws.

The study’s authors emphasize that their work is not yet conclusive but offers a viable path forward. Future observations, including higher-resolution CMB maps from missions like Planck’s successor (CMB-S4) or improved supernova measurements, could either confirm or refute the role of primordial magnetic fields. If validated, the discovery would mark a paradigm shift in cosmology, bridging two of its most stubborn mysteries: the universe’s expansion and the origin of its magnetic fields.

The research was published in a peer-reviewed journal, with the team now awaiting follow-up data to strengthen their case. No Malaysian institutions were directly involved, but the findings align with global efforts to refine the standard model of cosmology—a pursuit with implications far beyond astronomy.