Dark energy data suggest Einstein was right

What happened

An international consortium of scientists studying dark energy said Tuesday their three-dimensional map of the universe over 11 billion years suggested the cosmos wasn’t steadily expanding, but acting more like Albert Einstein predicted in his 1915 general theory of relativity.

Who said what

Cosmologists since 1998 have theorized that a mysterious invisible force dubbed dark energy was pushing the universe apart at an ever-faster rate. Scientists gathering and studying data from the Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory in Arizona found it “may not be an unchangeable force,” Reuters said.

“Dark energy seems to be dynamical and weakening,” said astrophysicist Mustapha Ishak-Boushaki of the University of Texas at Dallas, a leader of the DESI working group. The “strong hint” that the universe need not be “accelerating forever in its expansion” is the “most important finding since the discovery of cosmic acceleration in 1998.” Scientists still don’t understand dark energy — believed to make up 68% of the universe, versus just 5% for everything visible and tangle — but the DESI findings that it’s “changing or weakening over time” would “upend astronomers’ standard cosmological model,” The Associated Press said.

What next?

The “new findings aren’t definitive,” and astronomers need “more data to overturn a theory that seemed to fit together so well” — but “there’s a lot riding on the answer,” the AP said. If dark energy is constant, the universe will continue to expand, “forever getting colder and emptier,” and if it’s strengthening, “the universe will expand so speedily that it’ll destroy itself in what astronomers call the Big Rip.” That wouldn’t happen “for billions of years,” astrophysicist David Spergel said to the AP. “But we’d like to know about it.”