A group of astronomers analyzing data from the James Webb Space Telescope (JWST) has found that some of the oldest galaxies in our universe appear much larger and brighter than expected, suggesting that these galaxies were This suggests that they formed and grew rapidly, potentially without the influence of dark matter.
The researchers say the discovery provides new clues to an alternative to dark matter, known as modified Newtonian mechanics (MOND).
“All the large galaxies we see in the nearby universe were expected to originate from these tiny pieces,” Stacey McGaw, an astrophysicist at Case Western Reserve University in Ohio, said in a statement. . “What dark matter theory predicts is not what we see.”
The gradual hierarchical evolution of galaxies, thought to be driven by cold dark matter, is a key component of the standard cosmological model of our universe, and is an essential component of the diversity of galaxies that dot the universe. It is widely accepted because it describes a certain shape or size.
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But JWST has yet to discover the dim signals expected to emanate from these tiny, primordial galaxy debris in the early universe, McGaw and colleagues say. Rather, the telescope’s data shows that the early galaxies were larger and brighter than expected, even though the research team looked further back in time. The researchers argue that these galaxies were too large and grew too quickly, far exceeding the predictions set by traditional cold dark matter models.
But this rapid growth is exactly in line with MOND’s predictions 26 years ago.
“The bottom line is ‘I told you so,'” McGaw said in a statement. “I grew up thinking it was rude to say that, but that’s the whole point of the scientific method: make a prediction and see if it comes true.”
The researchers note that some of the excessively bright sources recorded by JWST may be active supermassive black holes rather than galaxies, but that could be due to “the problem of too many early stars. , which isn’t very useful anyway because it just turns the problem into too many early supermassive stars’ black holes. ”
MOND claims that when gravity becomes extremely weak, it behaves differently than Isaacs-Newton predicted. An example of such a weakness is at the edge of the galaxy. The concept was proposed by Israeli physicist Mordechai Milgrom in 1982 as a way to explain the faster-than-expected rotation of galaxies without invoking dark matter or dark energy.
Although MOND has had some success, it has its fair share of detractors. Astronomers have found it difficult to integrate this idea into a unified framework that can explain a wide range of cosmological observations. In contrast, although the dark matter paradigm fits many observations, it cannot fully explain the phenomena predicted by MOND.
“We are caught between two very different theories that appear to be contradictory, despite applying closely related but inconsistent bodies of evidence. ,” McGough and colleagues wrote in a paper published Tuesday (November 12) in the Astrophysical Journal.
Although MOND is not a widely accepted theory in cosmology, researchers are confident that it makes predictions that are successful enough to be more than just a coincidence.
“That must be telling us something,” they note in their paper. “What it is remains as mysterious as the composition of dark matter.”
