Some of the oldest galaxies in our universe appear much larger and brighter than expected, suggesting they formed early and potentially grew rapidly without the influence of dark matter, says a team of astronomers who analyzed data from the James Webb Space Telescope (JWST). According to the researchers, the results provide new clues pointing to an alternative to dark matter known as modified Newtonian dynamics, or MOND.

“We would expect every large galaxy we see in the nearby universe to start with these small pieces,” Stacey McGaugh, an astrophysicist at Case Western Reserve University in Ohio, said in a statement. he said. “What the dark matter theory predicts is not what we see.”

It is widely accepted that the gradual, hierarchical evolution of galaxies, believed to be driven by cold dark matter and an important component of the standard cosmological model of our universe, explains the diversity of shapes and sizes of galaxies scattered across space.

Despite all this, McGaugh and his colleagues say JWST has not yet detected the faint signals expected to be emitted from these small, primitive galaxy fragments in the early universe. Instead, the telescope’s data show that the first galaxies were larger and brighter than expected, even as the team looked deeper into the past. Researchers say these galaxies are growing very large and very fast; This is far beyond the expectations set by traditional cold dark matter models.

However, this rapid growth exactly coincides with MOND’s predictions 26 years ago.

“The point is, I told you so,” McGaugh said in a statement. “I was raised to say it was rude, but that is the essence of the scientific method: making predictions and then testing them to make them come true.”

The researchers noted that some of the extremely bright sources recorded by JWST may be active supermassive black holes rather than galaxies, but this “still doesn’t help because it turns the problem of too many early stars into one of too many early supermassive stars” into “black holes”.

MOND states that when gravity becomes extremely weak, it behaves differently than Isaac Newton predicted. An example of this weakness is the neighborhood of galaxies. The concept was proposed by Israeli physicist Mordechai Milgrom in 1982 as a way to explain the faster-than-expected rotation of galaxies without the use of dark matter or dark energy.

Although MOND has had some successes, it has many criticisms. Astronomers have struggled to integrate this idea into a single framework that can explain a wide range of cosmological observations. In contrast, the dark matter paradigm fits many observations but does not fully explain the phenomena predicted by MOND.

“We are stuck between two different theories that seem irreconcilable despite the fact that they apply to closely related but disproportionate sets of evidence,” McGaugh and colleagues wrote in their paper published Tuesday, Nov. 12, in The Astrophysical Journal. .

Although MOND is not a universally accepted theory in cosmology, researchers believe it makes sufficiently successful predictions that it cannot be just a coincidence.

“This probably tells us something,” they note in the paper. “What dark matter is, as well as its composition, remains a mystery.”