New Theory May Resolve the Hubble Tension
A recent study has suggested a possible explanation for the ongoing discrepancy in measurements of the universe’s expansion rate — the so-called Hubble tension. Researchers from the Universities of Bonn and St. Andrews are proposing that the alternative MOND theory of gravity could resolve the observed discrepancies, suggesting that local matter density variations may account for the differences.
The universe is expanding, causing galaxies to move away from each other at a proportional speed to the distance between them. This expansion is described by the Hubble-Lemaitre constant, a fundamental parameter in cosmology. However, different measurement methods have provided contradictory values for this constant, leading to the Hubble tension puzzle for cosmologists.
The new study, published in the Monthly Notices of the Royal Astronomical Society, proposes that using an alternative theory of gravity can explain the discrepancies in the measured values. According to the study, MOND accurately predicts the existence of under-densities or “bubbles” in the distribution of matter, potentially resolving the Hubble tension.
Professor Pavel Kroupa from the University of Bonn explains, “The standard model of cosmology does not account for such under-densities or ‘bubbles,’ as matter should be evenly distributed in space. However, the working groups from the Universities of Bonn and St. Andrews used a modified theory of gravity in a computer simulation and found that MOND accurately predicts the existence of such bubbles.”
The study suggests that assuming gravity behaves according to the assumptions of MOND would cause the Hubble tension to disappear, indicating that the observed deviations in the measured values are due to irregularities in the distribution of matter.
The research, which involved the University of Saint Andrews (Scotland) and Charles University in Prague (Czech Republic), was funded by the British Science and Technology Facilities Council. This proposed solution to the Hubble tension paves the way for further exploration into the understanding of the universe’s expansion and the forces that govern it.