Webb telescope helps refines Hubble constant, suggesting resolution rate debate

Summary

Scientists have made a new calculation of the speed at which the universe is expanding, using the data taken by the powerful new James Webb Space Telescope on multiple galaxies. Webb’s image of one such galaxy, known as NGC 1365. Credit: NASA, ESA, CSA, Janice Lee (NOIRLab), Alyssa Pagan (STScI) For the past decade, scientists have been trying to get to the bottom of what seemed like a major inconsistency in the universe. The universe expands over time, but how fast it's expanding has seemed to differ depending on whether you looked early in the universe's history or the present day. If true, this would have presented a major problem to the gold-standard model that represents our best understanding of the universe. But thanks to the new James Webb Space Telescope, scientists from the University of Chicago have been able to take new and better data—suggesting there may be no conflict after all. "This new evidence is suggesting that our Standard Model of the universe is holding up," said UChicago Prof. Wendy Freedman, a leading figure in the debate over this rate of expansion, known as the Hubble constant. "It doesn't mean we won't find things in the future that are inconsistent with the model, but at the moment the Hubble constant doesn't seem to be it," she said. Space, stars and supernovae There are currently two major approaches to calculating how fast our universe is expanding. The first approach is to measure the remnant light left over from the Big Bang, which is still traveling across the universe. This radiation, known as the cosmic microwave background, informs astronomers about what the conditions were like at early times in the universe. Freedman, the John and Marion Sullivan University Professor in Astronomy and Astrophysics, specializes in a second approach, which is to measure how fast the universe is expanding right now, in our local astronomical neighborhood. Paradoxically, this is much trickier than seeing back in time, because accurately measuring d...