JWST may have solved the puzzle of the expansion rate of the universe
Recent analyses of data from the James Webb Space Telescope (JWST) have yielded new measurements of the expansion rate of the universe, providing new insights into the long-standing debate known as the “Hubble tension.” For years, astronomers have struggled to reconcile two major methods for measuring the expansion of the universe, leading to conflicting results. The new study, led by University of Chicago astronomer Wendy Freedman, measured the expansion rate using light from 10 nearby galaxies using three different methods. The findings suggest that the observed conflict between these methods may not be as significant as once thought.
Understanding the Hubble Voltage
The Hubble constant, which measures the rate of expansion of the universe, is a key factor in understanding the history of the universe. Traditionally, two methods have been used to calculate it: one based on the cosmic microwave background radiation from the Big Bang, and the other by observing stars in nearby galaxies.
The former method has consistently produced a lower value, while the latter has produced a higher rate, leading to speculation that something fundamental might be missing from our current cosmological models. This missing data has been termed the Hubble voltage.
New data from the Webb telescope
Using the Webb telescope, Freedman and her team analyzed the light from 10 nearby galaxies, using three independent methods to measure the expansion rate. These methods included Cepheid variable stars, the Tip of the Red Giant Branch, and carbon stars, all of which are known for their predictable brightness. The results matched closely with the cosmic microwave background method, suggesting that the two previously conflicting measurements may not be as different as previously thought.
Impact on cosmology
The findings of this study are important because they suggest that the standard model of the evolution of the universe may still be accurate. While the debate over the Hubble voltage continues, these new data provide a clearer picture and can guide future research. Freedman told Phys.org states that continued observations with the Webb telescope are essential to solving this problem and understanding its broader implications for cosmology.
