The journal *Nature Astronomy* reports that a recent study offers a new perspective on one of the greatest mysteries of modern cosmology, known as the " Hubble tension" —the discrepancy between different methods of measuring the expansion rate of the universe. Canadian scientists from Simon Fraser University believe the key to solving this puzzle may lie in primordial magnetic fields , subtle structures that likely originated in the early stages of the universe's existence.
The Hubble constant is a parameter that describes the rate at which galaxies are moving away from each other. It is currently determined using two highly precise methods: one based on observing distant galaxies and supernovae, and the other on analyzing the cosmic microwave background radiation , the faint afterglow of the Big Bang. However, the two methods yield different results, a situation known as the crisis of modern cosmology.
According to the researchers, ancient magnetic fields may have influenced the recombination process , the stage during which electrons and protons combined to form the first atoms. Changes in conditions during this stage may have led to a slight distortion in the structure of the cosmic microwave background radiation, and consequently, in the way scientists derive the value of the Hubble constant from it.
To test this hypothesis, the researchers used supercomputers to perform a detailed simulation of the early universe, then compared the results with observational data collected by space telescopes and the Planck satellite , allowing them to assess how well this new approach matched actual measurements.
The researchers assert that this approach not only offers a potential solution to the Hubble tension but also contributes to understanding the origin of the magnetic fields observed today in galaxies and intergalactic space. Future observations and more precise experiments will determine whether the traces of primordial magnetism truly hold the key to the history of the universe's expansion.
