New observations from the James Webb Space Telescope suggest that a new feature in the universe—not a flaw in telescope measurements—may be behind the decade-long mystery of why the universe is expanding faster today than it did in its infancy billions of years ago. The new data confirms the Hubble Space Telescope measurements of distances between nearby stars and galaxies, offering a crucial cross-check to address the mismatch in measurements of the universe's mysterious expansion. Known as the Hubble tension, the discrepancy remains unexplained even by the best cosmology models. The research builds on the work of Adam Riess of Johns Hopkins University and his Nobel Prize–winning discovery that the universe's expansion is accelerating owing to a mysterious "dark energy" permeating vast stretches of space between stars and galaxies.