Astronomers studying the largest 3D map of the universe yet have found hints that dark energy is weakening over time. This could mean that our most trusted cosmological models may be wrong, as dark energy’s strength was traditionally thought to be constant.
In the late 1990s, astronomers discovered that the universe’s expansion rate appears to be accelerating. Dark energy was blamed for this phenomenon, acting as an anti-gravity force with a constant potency. However, recent data from the Dark Energy Spectroscopic Instrument (DESI) suggests otherwise. DESI, located at the Kitt Peak National Observatory in Arizona, observed 5,000 galaxies simultaneously and analyzed three years of data covering 15 million galaxies.
The team’s results are consistent with standard cosmological models, including the cosmological constant, but combine well with other observations to indicate that dark energy may not be a constant force after all. The new dataset is more than twice as large as the initial one and strengthens the idea that dark energy is dynamic rather than static.
However, experts caution that it’s still early days in the debate. “The significance of this claim is low,” says Andy Taylor from the Royal Observatory Edinburgh. “It might be a statistical fluke or biased data.” Henk Hoekstra from Leiden University agrees: “If these findings can be confirmed, this would be revolutionary.”
Weakening dark energy’s strength would change the outlook for the universe’s future. A “Big Rip” scenario, where dark energy grows stronger and tears apart all structure in the universe in around 22 billion years’ time, now seems less likely.
The discovery raises fundamental questions about the nature of our universe, as researchers continue to explore new data and theories. DESI Director Michael Levi emphasizes: “Whatever the nature of dark energy is, it will shape the future of our universe.”
Source: https://skyandtelescope.org/astronomy-news/dark-energy-changing-different-cosmic-fate