Small galaxies without dark matter were already causing quite a stir a few years ago. But now evidence has been found for the first time of a very large galaxy without dark matter. This does not fit the Standard Model of cosmology at all.
It is related to the galaxy NGC 1277. It is a spiral galaxy located about 220 million light-years from Earth. In 2018 it was discovered that no new stars were forming, but that the system consisted only of old stars that formed billions of years ago. It is called a remnant galaxy, which means it has not interacted with any other galaxies. It is likely the remnant of a giant galaxy that originated in the early universe.
No dark matter
Researchers from the Institute for Astrophysical Research IAC in the Canary Islands and La Laguna University to have Find out now NGC 1277 has no dark matter at all. This is the first time that in such a large galaxy – the mass is many times greater than our Milky Way – no evidence has been found of that now known but invisible part of the universe. “This does not fit with current cosmological models that assume the existence of dark matter,” explains lead researcher Sebastien Comeron.
According to the Standard Model, very large galaxies contain large amounts of dark matter. This dark matter is basically invisible. We can observe this because of the strong gravitational force that matter exerts on nearby stars and gases.
challenge puzzle
This material was not found in the ancient galaxy NGC 1277. “The reason we decided to study NGC 1277 with a spectrometer is because it helps us understand how the first galaxies formed,” Comeron explains. This allowed the researchers to measure the motion of stars up to 20,000 light-years outside the galaxy and conclude that there could be no more than 5 percent dark matter within the observed radius and perhaps no dark matter at all.
This is inconsistent with current models. They assume that a galaxy the size of NGC 1277 should be composed of at least 10% dark matter and a maximum of 70%. “The discrepancy between the observations and what we expected is a mystery, and possibly a challenge to the Standard Model,” said researcher Ignacio Trujillo.
Two unsatisfactory explanations
Is there no explanation whatsoever for why dark matter doesn’t exist? Yes, yes, the article mentions two. “One possibility is that because of the gravitational interaction with the surrounding galactic medium, the dark matter disappeared,” explains researcher Anna Ferret-Matteo. “Another explanation is that dark matter was kicked out of the system when NGC 1277 formed from the protogalaxies long ago.”
But for the authors, both explanations are unsatisfactory “so the mystery of how a massive galaxy could have formed without dark matter remains a mystery for the time being,” says Comeron, who continues to investigate the mystery with his team.
No exceptions
If NGC 1277 does not contain dark matter, this in no way confirms alternative models that say, for example, that dark matter does not exist at all. While dark matter can be lost in a particular galaxy, the modified law of gravity must be universal. There can be no exceptions, so a galaxy without dark matter is a refutation of these types of dark matter alternatives.”
We wrote earlier about how Hubble confirmed two years ago that there are galaxies without dark matter. Then the telescope looked at the galaxy NGC 1052-DF2, but this is not the only galaxy. For example, researchers reported in 2018 that galaxy NGC 1052-DF4 also contains almost no dark matter. And other researchers discovered nineteen more dwarf galaxies in 2020 that appear to not contain any dark matter. However, all of these galaxies were relatively small, so now a massive one has also been found.
“Subtly charming tv fanatic. Introvert. Thinker. Alcohol maven. Friendly explorer. Certified coffee lover. Infuriatingly humble food junkie. Typical reader.”