A recent study utilizing data from the James Webb Space Telescope has provided new insights into the ongoing debate surrounding the rate of expansion of the Universe, referred to as the “Hubble tension”. This longstanding dispute has raised questions about our understanding of the laws of physics and potentially points to missing components in the theoretical model of the Universe.
Nearly a century ago, American astronomer Edwin Hubble discovered the expanding nature of the Universe and calculated the rate of this expansion, now known as the Hubble constant (H₀). However, scientists have since found that modern measurements of H₀ diverge from theoretical predictions, giving rise to the so-called “Hubble tension”. This discrepancy has sparked numerous discussions and speculations, suggesting that our comprehension of the Universe may be incomplete.
Two prominent research groups are at the forefront of efforts to measure H₀. The first, led by Nobel Prize Laureate Adam Riess from Johns Hopkins University, found that their results indicate H₀ to be approximately 8% higher than the theoretical prediction. This suggests that the Universe is expanding at a faster rate than expected based on the standard model, prompting theories about potential unknown components or effects driving this acceleration.
Conversely, the team led by Wendy Friedman from the University of Chicago argues that more precise and unbiased measurements are necessary. Her group consistently obtains values of H₀ closer to theoretical predictions, casting doubt on the existence of the Hubble tension.
The arrival of the James Webb Telescope in 2022 had the scientific community eagerly anticipating Friedman’s analysis, which utilizes observations of three different types of stars for H₀ measurements. This analysis was expected to either confirm or refute the presence of the Hubble tension. The recently published results revealed that two types of stars provided H₀ values in line with theory, while the third type, also studied by the Riess team, confirmed a higher value, reigniting the debate once more.