The galaxies, each as vast as the Milky Way, are baffling because most scientific models for galaxy evolution suggest processes that would have been slow and inefficient, said Stijn Wuyts, an astronomer from the University of Bath in the United Kingdom.

A new study suggests galaxies in the early universe appear much larger and brighter than expected, precisely as predicted by modified Newtonian dynamics, or MOND.

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.