The James Webb Space Telescope (JWST) has provided new data that intensifies the "Hubble tension," a discrepancy in measurements of the universe's expansion rate. While the cosmic microwave background suggests a Hubble constant of about 67 km/s/Mpc, measurements using Cepheid variable stars indicate around 73 km/s/Mpc. JWST's findings align with the latter, suggesting the universe's expansion may involve unknown physics, such as early dark energy or new properties of dark matter, challenging current cosmological models.
NASA's James Webb Space Telescope has detected a second lensed supernova in the distant galaxy MRG-M0138, thanks to the gravitational lensing effect of the galaxy cluster MACS J0138.0-2155. This rare event, following the first supernova named Requiem discovered in 2016, provides astronomers with a unique opportunity to study cosmic events and measure the universe's expansion rate, known as the Hubble constant. The newly discovered supernova, dubbed Supernova Encore, along with Requiem, represents the most distant pair of 'standard candle' supernovae ever found, which will help in obtaining a precise measurement of the Hubble constant when observed in infrared around 2035.
