Back

Dark energy: mysterious cosmic force appears to be weakening, say scientists

“What we are seeing is deeply intriguing. It is exciting to think that we may be on the cusp of a major discovery about dark energy and the fundamental nature of our universe.”
Dark energy was discovered in the late 1990s when astronomers used distant supernova explosions to investigate how the rate of cosmic expansion has changed over time.

The expectation was that gravity should counteract the expansion that has been underway since the big bang,
but instead, the supernovae indicated that the rate of expansion was accelerating, propelled by some unknown force that scientists called dark energy.

Dark energy has been assumed to be a constant, which would imply the universe will meet its end in a desolate scenario called the “big freeze”, when everything is eventually so far apart that even light cannot bridge the gap between galaxies.
The latest findings, announced on Thursday at the American Physical Society’s Global Physics Summit in Anaheim, California, challenge that prevailing view.
Desi uses its 5,000 fibreoptic “eyes” to map the cosmos with unprecedented precision.
Its latest data release captures 15m galaxies, spanning 11bn years of history, which astronomers have used to create the most detailed three-dimensional map of the universe to date.
The results suggest that dark energy reached a peak in strength when the universe was about 70% of its current age and it is now about 10% weaker.
This would mean the rate of expansion is still accelerating, but that dark energy is gently lifting its foot off the pedal.
https://www.theguardian.com/science/2025/mar/19/dark-energy-mysterious-cosmic-force-weakening-universe-expansion?CMP=Share_iOSApp_Other