Weird Galaxy Without Dark Matter Baffles Astronomers As It Contradicts Popular Beliefs About the Universe

Evidence for dark-matter-free galaxies was discovered by a team of Dutch astronomers. They found no evidence of dark matter in the galaxy AGC 114905.

The so-called super-dwarf galaxy AGC 114905 is roughly 250 million light-years away, TechExplorist said. It's about the same size as our Milky Way, but there are a thousand times fewer stars in it.

The popular belief is that all galaxies, particularly super-dwarf galaxies, can only exist if dark matter holds them together. Despite conducting comprehensive measurements using powerful telescopes for almost forty hours, researchers detected no evidence of dark matter in the galaxy AGC 114905.

According to CNet, the team will publish its findings in the Royal Astronomical Society's Monthly Notices.

Researchers Find Dark Matter-Free Galaxies

According to astronomers, they've discovered six galaxies with either very little or no dark matter. The researchers focused on AGC 114905, a presumably dark-matter-free area to bolster their case. It's around the size of the Milky Way, but with a thousand times fewer stars, and it's 250 million light-years away from Earth. As a result, it's a little dim.

To discover the presence of dark matter in AGC 114905, the researchers utilized a common approach that includes charting the position and rotation speed of the galaxy's gas. They discovered that the motions of the gas could be explained fully by regular matter alone after 40 hours of observation with the high-powered Very Large Array Radio Telescope in New Mexico.

"The problem remains that the theory predicts that there must be dark matter in AGC 114905," Pavel Mancera Piña of the Kapteyn Astronomical Institute at the University of Groningenour and an author of the study, said in a statement, referring to classic dark matter hypotheses. "Observations say there isn't -- in fact, the difference between theory and observation is only getting bigger."

Why The Lack of Dark Matter

The researchers outline all probable causes for the lack of dark matter in their scientific paper. Large neighboring galaxies, for example, may have drained AGC 114905 of dark matter. Mancera Piña said in a SciTechDaily report that there are none. According to Mancera Piña, they have to incorporate extreme parameter values beyond the normal range in the most well-known galaxy formation framework, the so-called cold dark matter hypothesis. The researchers also could not duplicate the movements of the gas within the galaxy using modified Newtonian dynamics, an alternative to cold dark matter.

There is one additional assumption, according to the researchers, that might influence their results. That's the angle at which they believe they're looking at the galaxy. However, that angle must depart significantly from our estimate before dark matter may be considered again, explains co-author Tom Oosterloo.

Meanwhile, the team is delving further into a second ultra-diffuse dwarf galaxy. Suppose no evidence of dark matter is found in that galaxy again. In that case, the argument for dark matter-poor galaxies becomes much stronger.

The study by Mancera Piña and colleagues is not an exception. A Dutch-American, Pieter van Dokkum (Yale University, USA) has previously identified a galaxy with very little dark matter. Mancera Piña and colleagues' approaches and measurements are more reliable.

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