New 3D Cosmic Map Raises Questions Over Future of Universe, Scientists Say

The biggest ever 3D map of the universe, featuring more than 6m galaxies, has been revealed by scientists who said it raised questions about the nature of dark energy and the future of the universe. From a report: The map is based on data collected by the Dark Energy Spectroscopic Instrument (Desi) in Arizona and contains three times as many galaxies as previous efforts, with many having their distances measured for the first time. Researchers said that by using this map, they have been able measure how fast the universe has been expanding at different times in the past with unprecedented accuracy. The results confirm that the expansion of the universe is speeding up, they added. However, the findings have also raised the tantalising possibility that dark energy -- a mysterious, repulsive force that drives the process -- is not constant throughout time as has previously been suggested. Dr Seshadri Nadathur, a co-author of the work and senior research fellow at the University of Portsmouth's Institute of Cosmology and Gravitation, said: "What we are seeing are some hints that it has actually been changing over time, which is quite exciting because it is not what the standard model of a cosmological constant dark energy would look like." Prof Carlos Frenk, from Durham University and a co-author of the research, said that if dark energy was indeed constant in time, the future of the universe was simple: it would expand on and on, for ever. But if the hints found in the map stood up, that would be called into question. The research, which has been published in a series of preprints a" meaning it has yet to be peer-reviewed a" reveals how the team first created the 3D map, then measured patterns in the distribution of galaxies that relate to sound waves that occurred in the early universe, known as baryon acoustic oscillations.

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