Solving the Hubble Tension: Redshift Drift Offers New Insights
Scientists propose a new method called redshift difference to measure the expansion rate of the universe. Currently, the expansion rate, known as the Hubble parameter, can only be measured in the present. However, by observing distant galaxies that are gravitationally lensed by closer galaxies, researchers can compare the redshifts of multiple images of the same galaxy taken at different times. This method could provide insights into the evolution of cosmic expansion and help determine whether it is due to general relativity or an extension of Einstein's model. While current telescopes cannot detect the small redshift drift, future telescopes like the Extremely Large Telescope (ELT) may be able to observe this phenomenon in the coming years.
