\n However, the nature of dark energy has remained a mystery, and its role in the universe\u2019s expansion has been called into question before<\/a>.\n <\/p>\n \n Last year, a consortium of hundreds of researchers using data from the Dark Energy Spectroscopic Instrument (DESI) in Arizona, developed the largest ever 3D map <\/a>of the universe. The observations hinted at the fact that dark energy may be weakening over time, indicating that the universe\u2019s rate of expansion could eventually slow.\n <\/p>\n \n Now, a study published<\/a> November 6 in the journal Monthly Notices of the Royal Astronomical Society provides further evidence that dark energy might not be pushing on the universe with the same strength it used to.\n <\/p>\n \n The DESI project\u2019s findings last year represented \u201ca major, major paradigm change \u2026 and our result, in some sense, agrees well with that,\u201d said Young-Wook Lee, a professor of astrophysics at Yonsei University in South Korea and lead researcher for the new study.\n <\/p>\n \n Lee and his colleagues\u2019 work builds on the evolving understanding of dark energy, suggesting that the universe\u2019s expansion has already started to slow down \u2014 something that could alter the fate of the universe itself. \u201cDark energy is there, but the present universe has already entered a decelerating phase, today,\u201d Lee said. \u201cSo the fate of the universe could change. And if you can change the fate of the universe, that is really important progress in cosmology.\u201d\n <\/p>\n \n To reach their conclusions, the researchers analyzed a sample of 300 galaxies containing Type 1a supernovas and posited that the dimming of distant exploding stars was not only due to their moving farther away from Earth, but also due to the progenitor star\u2019s age.\n <\/p>\n \n \u201cBefore our work, Type Ia supernovae were thought to explode with nearly identical intrinsic brightness, making them highly reliable \u2018standard candles,\u2019\u201d said study coauthor Junhyuk Son, a doctoral candidate of astronomy at Yonsei University. \u201cHowever, we found that their luminosity actually depends on the age of the stars that produce them \u2014 younger progenitors yield slightly dimmer supernovae, while older ones are brighter.\u201d\n <\/p>\n \n Son said the team has a high statistical confidence \u2014 99.99% \u2014 about this age-brightness relation, allowing them to use Type 1a supernovas more accurately than before to assess the universe\u2019s expansion.\n <\/p>\n \n \u201cIf confirmed, this would represent the most significant shift in cosmology since the discovery of dark energy in 1998,\u201d Son said. \u201cIt would suggest that the (expansion of the) universe is no longer accelerating today and that dark energy is not a constant force but something that evolves over time. This discovery would open an entirely new chapter in our understanding of the physical nature of dark energy, how it has changed throughout cosmic history, and what it ultimately means for the fate of the universe.\u201d\n <\/p>\n \n Eventually, if the expansion continues to slow down, the universe could begin to contract, ending in what astronomers imagine may be the opposite of the big bang \u2014 the big crunch<\/a>. \u201cThat is certainly a possibility,\u201d Lee said. \u201cEven two years ago, the Big Crunch was out of the question. But we need more work to see whether it could actually happen.\u201d\n <\/p>\n \n The new research proposes a radical revision of accepted knowledge, so, understandably, it is being met with skepticism.\n <\/p>\n \n \u201dThis study rests on a flawed premise,\u201d Adam Riess, a professor of physics and astronomy at the Johns Hopkins University and one of the recipients of the 2011 Nobel Prize in physics, said in an email. \u201cIt suggests supernovae have aged with the Universe, yet observations show the opposite \u2014 today\u2019s supernovae occur where young stars form. The same idea was proposed years ago and refuted then, and there appears to be nothing new in this version.\u201d\n <\/p>\n \n Lee, however, said Riess\u2019 claim is incorrect. \u201cEven in the present-day Universe, Type Ia supernovae are found just as frequently in old, quiescent elliptical galaxies as in young, star-forming ones \u2014 which clearly shows that this comment is mistaken. The so-called paper that \u2018refuted\u2019 our earlier result relied on deeply flawed data with enormous uncertainties,\u201d he said, adding that the age-brightness correlation has been independently confirmed by two separate teams in the United States and China.\n <\/p>\n \n Other experts in the field who were not involved with the study echoed some of Riess\u2019 concerns. Dan Scolnic, an associate professor of physics at Duke University in Durham, North Carolina, noted that the study makes a leap from host galaxy age to supernova age that isn\u2019t physically justified. \u201cThe authors are proposing ideas that the community has already tested and corrected for with much larger data sets. The universe is still accelerating just fine,\u201d Scolnic said.\n <\/p>\n \n Dillon Brout, an assistant professor in the departments of astronomy and physics of Boston University, pointed out via email that the paper raises a fair question about how the ages of supernova progenitors change over cosmic time, adding that it is always important to challenge our way of thinking in order to a better understand of the universe. \u201cHowever, the way they model that evolution is not supported by observations nor by our understanding of how these systems form. Modern supernova analyses already account for the connection between brightness and the environments where these stars originate, which captures most of the effect they discuss,\u201d he added.\n <\/p>\n \n \u201cExtraordinary claims require extraordinary evidence,\u201d Dragan Huterer, a professor of physics at the University of Michigan in Ann Arbor, said in an email, noting that he does not feel the new research \u201crises to the threshold to overturn the currently favored model.\u201d\n <\/p>\n \n Lee is aware that the work might be controversial. \u201cWe have a long way to go to convince everyone in the supernova cosmology community,\u201d he said. \u201cThere are still many people who are strongly against (our results), so a lot of debate and discussions should happen in the near future.\u201d\n <\/p>\n![\"This](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2025\/11\/hubble-sn2022aajn-potw2504a.jpg\")
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