(CN) — When astronomers started looking at new images of the deep universe obtained from the James Webb Space Telescope, they expected to see distant galaxies the way the standard theories of physics and cosmology predicted they would look. Instead, what they found could upend physics and astronomy as we know it.
“The universe is really shouting at us that there’s something more going on than just mass that we can’t see,” said Stacy McGaugh, a professor of astronomy at Case Western Reserve, and the lead author of the study published in The Astrophysical Journal on Tuesday on those images.
In the standard model of how the universe formed, an invisible, hypothetical and little understood mass called dark matter had an important gravitational effect on how hydrogen and photons formed first into small clusters and then gradually clumped together to form the earliest stars and galaxies.
To better understand dark matter and peer into the deepest and earliest parts of the universe the U.S., Canadian and European space agencies launched the James Webb Space Telescope into space in 2021.
Astronomers expected the infrared images the telescope took to show distant galaxies in small clusters that emit dim lights in line with the standard model of how the universe formed.
Instead, those galaxies were in much larger clusters and emitted more brightly than they thought.
To McGaugh, that calls into question the standard theory around dark matter and gives validity to an alternative theory called Modified Newtonian dynamics, or MOND.
Developed by Israeli scientist Mordehai Milgrom in the 1980s, MOND postulates that galaxies form and expand much quicker under a stronger force of gravity than the standard model accounts for. The force of gravity eventually slows the expansion, then the mass clumps together to form a galaxy.
In the MOND model, no hypothetical dark matter is involved.
The telescope’s images that looked further and further and earlier and earlier into the evolution of the universe, seems to fit with MOND’s theory of rapid formation of galaxies, according to the researchers.
“Despite the predictive successes of MOND, we do not yet know how to construct a cosmology based on it,” the researchers write in their study.
While the standard model, called the Lambda-CDM model, provides a good explanation of cosmological movement and observations, it doesn’t provide a good explanation for many specific astronomical phenomena that are better explained by MOND, they add.
“We find ourselves caught between two very different theories that seem irreconcilable despite applying to closely related yet incommensurate lines of evidence. The simple force law hypothesized by MOND has made enough successful a priori predictions that it cannot be an accident: it must be telling us something. What that is remains as mysterious as the composition of dark matter,” they say.
MOND hasn’t found much purchase or prominence in the shadow of bedrock theories of physics developed by titans of the field like Isaac Newton in the 17th century and Albert Einstein in the 20th century, but that shouldn’t mean scientists should be afraid to look closely at evidence supporting MOND, McGaugh said.
Both astronomers and theoretical physicists should dig further into how MOND works, and its own contradictions, like why it’s excellent at predicting new phenomena, but not good at explaining things physicists already know, like particle physics, he added.
He lost sleep trying to come to terms with MOND and his own study, he added, and while he’s still agnostic about it, the evidence is there, McGaugh said.
“I’ve been basically telling them they’ve wasted their whole careers,” he added about other astronomers and physicists. “I’m sorry, don’t kill the messenger.”