Universe's expansion rate refined using supernova 'twins' ⚡ экспресс
The 'twin' method of Type Ia supernovae in the Hubble flow was applied to determine distances at z>0.015. The one-step transition from low redshifts confirms the classical three-step approach, but the Pantheon+ and CCHP compilations contain color errors due to underestimation of dust reddening or incorrect determination of light curve decline, distorting individual H0 estimates. A sample of 12 carefully selected supernovae with high-precision distances, including three Broad Line subtypes comparable to SN 1989B in M66, and tied to anchors with consistent Cepheid (SH0ES) and JAGB measurements (CCHP) for NGC 7250 and NGC 5643, yields H0 = 72.56±1.54(stat)±1.33(syst) km/s/Mpc with Cepheid calibration and 72.20±1.53(stat)±1.33(syst) km/s/Mpc with JAGB calibration. The mean H0 = 72.38±1.54(stat)±1.33(syst) km/s/Mpc. The results confirm the reality of the Hubble tension.
Type Ia supernovae are like light bulbs of a fixed wattage: the dimmer the light, the farther the source. Such supernovae serve as distance markers to remote galaxies. But cosmic dust, like a dirty window, dims and reddens the light, messing up the calculations. Astronomers led by Adam Riess sidestepped the problem: they compared only 'twins'—supernovae with identical properties, whose light traveled through similarly dusty regions. It's like gauging distance by lamps hidden in identical lampshades. The new data yield a universe expansion rate of about 72.4 km/s per megaparsec (that's 3.26 million light-years). That's noticeably faster than the ancient light from the Big Bang predicts. The discrepancy, known as the 'Hubble tension', has now grown even stronger.
🎯 It was precisely with type Ia supernovae that the accelerating expansion of the universe was discovered in 1998—a Nobel Prize-winning breakthrough.
🎬 Confirmation of the Hubble tension makes sci-fi scenarios where physical laws evolve just a little less fictional.