Space scientists believe that dark matter is a vital ingredient in galaxy formation, as this mysterious entity plays a crucial role in pulling together atoms of gas to form galaxies using its gravity. However, in an interesting development, scientists have now discovered 19 galaxies where dark matter is seemingly missing.
Do galaxies exist without dark matter?
This new finding has crucial significance, as it is expected to change the current understanding of dark matter and its role in the formation of galaxies. Even though dark matter is invisible, scientists can detect their presence as it makes the matter in the galaxy swirl faster it would if the matter we see made up the galaxy's whole mass.
It should be noted that this faster swirling can be measured precisely, and scientists consider this as proof of dark matter existence. But in the case of these 19 small galaxies, dark matter seems completely missing, and they behaved in such a way that they are being dominated by baryons, particles that made up ordinary matter.
The dark matter mystery continues
This is not the first time that scientists have discovered a galaxy without the presence of dark matter. In 2018, a research team led by Pieter van Dokkum, an astrophysicist at Yale University discovered a baryons-only galaxy model. However, many experts questioned the validity of the research conducted by Dokkum and his team.
Interestingly, the new research that helped identify 19 galaxies without dark matter adopted the same method that helped Dokkum to detect baryons-only galaxy model. In their research report published in the journal Nature Astronomy, researchers revealed that more studies on these galaxies could help to unlock some mysteries surrounding the absence of dark matter.
Dark matter or dark fluid?
A few months back, Jamie Farnes, a researcher at the University of Oxford, suggested that more than 95 percent of the universe is made up of a dark fluid with negative mass. He also made it clear that these negative masses are basically a hypothetical form of matter with negative gravity which repels all other materials around them.
Scientists who took part in this research believe that the new concept of dark fluid will help to answer two perplexing mysteries of space; why galaxies hold together and why the universe expands at an accelerating space every time.
However, the detection of galaxies without dark matter has added up to the mysteries again, and scientists are still unaware of how baryonic matter can pull together atoms of gas to form galaxies.