One of the universe's biggest paradoxes could be even weirder than we thought, James Webb telescope study reveals

New measurements taken with the James Webb Space Telescope (JWST) have deepened the scientific controversy of the Hubble tension — suggesting it may not exist at all.

For years, astronomers have found that the universe appears to be expanding at different speeds depending on where they look, a conundrum they call the Hubble tension. Some of the measurements agree with our best current understanding of the universe, while others threaten to break it.

When JWST came online in 2022, one team of researchers used the space telescope's unprecedented accuracy to confirm the tension exists. But according to the new results from a different team of scientists, the Hubble tension may arise from measurement error and be an illusion after all. Yet even these results are not definitive.

"Our results are consistent with the standard model. But they don't rule out that there's a tension there too," study lead author Wendy Freedman, an astrophysicist at the University of Chicago, told Live Science. "[The experience] is probably the closest thing to a rollercoaster — it's been exciting, but there are these moments when you've got to climb the hill again."

Hubble trouble

Currently, there are two gold-standard methods for figuring out the Hubble constant, a value that describes the expansion rate of the universe. The first involves poring over tiny fluctuations in the cosmic microwave background — an ancient relic of the universe's first light produced just 380,000 years after the Big Bang.

Related: 'It could be profound': How astronomer Wendy Freedman is trying to fix the universe

After mapping out this microwave hiss using the European Space Agency's Planck satellite, cosmologists inferred a Hubble constant of roughly 46,200 mph per million light-years, or around 67 kilometers per second per megaparsec (km/s/Mpc). This, alongside other measurements of the early universe, aligned with theoretical predictions.