NASA’s James Webb Space Telescope has made a ground-breaking discovery that could shatter our understanding of the universe.

The telescope has detected six ancient galaxies, dubbed “universe breakers”, dating back to when the universe was just 3% of its current age.

Equipped with infrared-sensing instruments capable of detecting light emitted by the most ancient stars and galaxies, the telescope has found galaxies far larger than what was presumed possible for galaxies so early after the big bang. The galaxies’ existence could upend current theories of cosmology.

Dr Erica Nelson of the University of Colorado Boulder, and a co-author, spotted a series of “fuzzy dots” that appeared unusually bright and red while sifting through images. These galaxies appeared to be roughly 13.5 billion years old, placing them about 500m-700m years after the big bang. These would not be the oldest galaxies observed by James Webb, as last year, scientists spotted four galaxies that date to about 350m years after the big bang. However, these were far smaller.

“The discovery of such massive galaxies so soon after the big bang suggests that the dark ages may not have been so dark after all, and that the universe may have been awash with star formation far earlier than we thought,” commented Dr. Emma Chapman, an astrophysicist at the University of Nottingham.

The existence of such massive galaxies close to the dawn of time would require scientists to revisit some basic rules of cosmology, as well as the theory that the first galaxies were seeded from small clouds of stars and dust. Existing models suggest that after a period of rapid expansion, the universe spent a few hundred million years cooling down enough for gas to coalesce and collapse into the first stars. Galaxies then began to form, leading to a period known as the dark ages.

The team is planning to obtain spectrum images, which can provide more accurate distance information and allow better estimates of mass. “A spectrum will immediately tell us whether or not these things are real,” said Joel Leja, an assistant professor of astronomy and astrophysics at Penn State University and a study co-author.

While the discovery has caught scientists off guard, further observations will be required to confirm the discovery before existing models can be abandoned.