The formation of galaxies in the early universe would not respond to the most widespread theory among scientistswhich contemplates the existence of dark matter. A research team, using data from the space telescope James Webbhas refuted this version and has taken up another hypothesis.
The standard model predicted that the Webb would see weak signals from small, primitive galaxiesbut according to a study published The Astrophysical Journalthe data does not confirm that dark matter helped the first stars and galaxies clump together.
In contrast, older galaxies are large and bright, according to an alternative theory of gravity, which challenges astronomers’ understanding of the early universeindicates the research, led by Case Western Reserve University, of USA. “What the dark matter theory predicted is not what we see,” explained Stacy McGaugh, one of the study’s signatories.
The research contrasts the Modified Newtonian Dynamics (MOND) system, formulated in 1998, with the Lambda-CDM model (LCDM) to explain the formation of the first galaxies. The LCDM contemplates the existence of cold dark matter and predicts that galaxies formed by gradual accretion of matter from small to larger structures, due to the extra gravity provided by the dark matter mass.
For its part, MOND, on which the new study is based, considers that, instead of dark matter, it would be modified gravity who could have played a role in the formation of the first galaxies. Furthermore, with this system the creation of structures in the early universe would have been very fast, much faster than what was assumed by the LCDM.
“The astronomers they invented dark matter to explain how we go from a very smooth primitive universe to large galaxies with a lot of empty space between them that we see today,” McGaugh said.
If galaxies formed by accretion, James Webb would have been able to see the small precursors of galaxies in the form of a light faint. “What was expected was that all the large galaxies that we see in the nearby universe would have formed from these small fragments,” explained the scientist. However, by observing with the space telescope earlier and earlier in the evolution of the universe, the signals are larger and brighter than expected.
MOND, with which dark matter does not exist, postulates that the mass that becomes a galaxy assembles quickly and initially It expands outward with the rest of the universe. Subsequently, the gravitational force slows the expansion and then reverses it, so that the subject collapses on itself to form a galaxy. These structures observed by Webb were predicted by MOND more than 25 years ago.
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