A group of astronomers, citing data from the James Webb Space Telescope (JWST), claims that some of the oldest galaxies in the universe could potentially have formed without the influence of dark matter.
«We are not seeing what the dark matter theory predicted», — says Stacey McGaugh, an astrophysicist at Case Western Reserve University in Ohio.
Dark Matter is believed to be a key component of the standard cosmological model of our Universe — and is widely recognized as explaining the diversity of shapes and sizes of galaxies scattered throughout spaceAt the same time, JWST did not detect the faint signals expected to emanate from these small, primitive fragments of galaxies in the early Universe. Instead, its data show that the early galaxies were larger and brighter than expected, and likely grew very rapidly — far outpacing the expectations set by conventional cold dark matter models. And this rapid growth is exactly in line with the predictions of the alternative dark matter theory — Modified Newtonian dynamics (MND).
At the same time, the researchers note that some of the excessively bright sources detected by JWST could be active supermassive black holes, not galaxies.
So what does the alternative theory say? According to GR, when gravity becomes extremely weak, it does not behave as Isaac Newton predicted (as an example, «neighborhoods of» galaxies are cited here). The concept itself was proposed in 1982 by the Israeli physicist Mordechai Milgrom — as a way to explain the faster-than-expected rotation of galaxies without the presence of dark matter or dark energy.In fact, GR has many critics, as the idea is difficult to integrate into a single framework that can explain a wide range of cosmological observations. Whereas the theory of dark matter is consistent with many observations, although it does not fully explain the phenomena predicted by GR.
«We are caught between two very different theories that seem irreconcilable despite the use of closely related but incommensurate evidence», — the team writes in a paper published on November 12 in The Astrophysical Journal (via Space.com).
At the same time, according to the researchers, despite the fact that GR is not a generally accepted theory in cosmology, it has made quite a few successful predictions, so this «cannot be a simple coincidence of».
«This tells us something, but what — is a mystery, as is the composition of dark matter».
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