The standard model for how galaxies formed in the early universe predicted that the James Webb Space Telescope (JWST) would see dim signals from small, primitive galaxies. But data are not confirming the popular hypothesis that invisible dark matter helped the earliest stars and galaxies clump together.

If another gravity theory is correct, "then the broader implications are enormous," astrophysicist Stacy McGaugh told Newsweek.

Astronomers have used the James Webb Space Telescope to observe three early ultra-massive galaxies, formed shortly after the Big Bang.