‘Real observations’ of galaxies support existence of invisible dark matter: Study

PTI, Apr 30, 2024, 5:38 PM IST

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New Delhi: By observing motions of stars and gas across galaxies, researchers have found evidence that they said supports the existence of dark matter.

While dark matter has not yet been directly detected and is therefore considered ‘invisible’, it is thought to explain various aspects of the observed universe.

The findings on dark matter were arrived at using ‘real, observed relationships’ between stars and galaxies could be a basis to test two different models to describe the universe, according to Francisco Mercado, lead author of the study published in the journal Monthly Notices of the Royal Astronomy Society.

One of these models works to answer the question – does invisible dark matter need to exist to explain how the universe works the way it does? On the other hand, according to the other model, can physicists explain how the universe works solely from matter that can be directly observed?

While currently, many physicists think that dark matter must exist to explain the motions of stars and galaxies, Mercado said his team ‘put forth a powerful test to discriminate between the two models’.

For the test, the researchers performed computer simulations using both normal and dark matter on observed features measured in real galaxies. The features included patterns in the motions of stars and gas in these galaxies.

The study led by the University of California, Irvine, US found that these features ‘are expected to appear in a universe with dark matter but would be difficult to explain in a universe without it’.

“We show that such features appear in observations of many real galaxies. If we take these data at face value, this reaffirms the position of the dark matter model as the one that best describes the universe we live in,” said Mercado.

While the team expects more debate within the research community to follow in the wake of the study, they said there ‘may be room for common ground’ as they found that only the simulations involving both normal and dark matter could explain the observed features of real galaxies.

“Simply put, the features we examined in observations require both the existence of dark matter and the incorporation of normal-matter physics,” said co-author Jorge Moreno, associate professor of physics and astronomy at Pomona College, California, US.

Now that the dark matter model of the universe appears to be the leading one, the next step is to see if it remains consistent across a dark matter universe, said Mercado.