New data suggests the unknown, unobservable force responsible for the universe’s expansion may be weakening.

A visualization of a 3D map of the universe, with Earth at the center and every dot representing a galaxy. 

‘Observable matter–everything from the coffee cup on your desk, to distant planets, to the largest and most ancient galaxies—makes up just 5% of the cosmos, meaning that dark energy is responsible for a whopping 68% of everything we think exists in the universe.

The notion of dark energy as a constant—which is to say, it manifested the same way 10 billion years ago as it does today, and as it will 10 billion years from now—is “baked into” the predominant model of the universe, Lambda-CDM, according to Rossana Ruggeri, a physicist at the University of Queensland who was involved in the DESI analysis.

“Results from the first batch of data gave a hint that dark energy might not behave like a simple cosmological constant—but it wasn’t strong enough to draw firm conclusions,” Ruggeri said in The Conversation. “Now, the second batch of data has made this evidence stronger.”

Though the data does not yet meet the statistical threshold physicists require to firmly declare a bona fide new discovery, the data strengthen physicists’ resolve that something is going on that will mean the model needs to be revised. “If dark energy is changing over time, it could have profound implications for the ultimate fate of the universe,” Ruggeri wrote.…’

(Isaac Schultz via Gizmodo)