Cepheids vary

NGC 5468 — the host galaxy of Cepheid. Joint photograph of the Webb and Hubble Space Telescopes, NASA/ESA

The Webb and Hubble telescopes confirm the rate of expansion of the universe, the puzzle remains

Webb's measurements provide new light on a decade-long mystery known as the Hubble stress - the differences in the age of the universe between the Hubble observations and past observations that remain unexplained * Prof. Adam Rees, winner