A decade-long survey of distant galaxies has confirmed that the universe is expanding at roughly 73 kilometers per second per megaparsec, a rate slightly higher than most models predicted and, according to the authors, “not ideal.”
The discrepancy, known as the Hubble tension, has resisted explanation for more than a decade. The new measurements, drawn from six observatories and more than 1.2 million galaxies, narrow the error bars without resolving the problem.
“We had hoped the new data would bring the two numbers closer together,” said Dr. Amara Osei, the survey’s lead author. “Instead they have moved further apart, which is scientifically interesting and personally disappointing.”
If the higher rate holds, the universe is roughly 13.4 billion years old, about 200 million years younger than the standard model suggests — a difference that cosmologists describe as “within the range of things that keep us up at night.”
The team plans to publish a second paper explaining what, if anything, could be done about it. A third paper will address whether it is appropriate to describe the universe as “behind schedule.”