Astronomers’ Simulations Bolster Case for Dark Matter’s Existence

A team of astronomers, including researchers from the University of California, Irvine, has conducted computer simulations that support the existence of dark matter, a hypothetical form of matter that has yet to be directly detected but is thought by many physicists to be necessary to explain various aspects of the observable universe.

Testing Models with Real, Observed Relationships

The study, published in Monthly Notices of the Royal Astronomical Society, addresses a fundamental debate in astrophysics: whether dark matter must exist to explain how the universe works or if physicists can explain it based solely on observable matter. The researchers used real, observed relationships as a basis to test two different models of the universe.

“We put forth a powerful test to discriminate between the two models,” said Francisco Mercado, lead author and recent Ph.D. graduate from the UC Irvine Department of Physics & Astronomy. “Our paper shows how we can use real, observed relationships as a basis to test two different models to describe the universe.”

Features in Galaxies Point to Dark Matter’s Existence

The team ran computer simulations with both normal and dark matter to explain the presence of intriguing features measured in real galaxies. These features, which describe patterns in the motions of stars and gas in galaxies, seem to only be possible in a universe with dark matter.

“Observed galaxies seem to obey a tight relationship between the matter we see and the inferred dark matter we detect, so much so that some have suggested that what we call dark matter is really evidence that our theory of gravity is wrong,” said co-author James Bullock, professor of physics at UCI and dean of the UCI School of Physical Sciences. “What we showed is that not only does dark matter predict the relationship, but for many galaxies it can explain what we see more naturally than modified gravity.”

The study also found that these features only appear in simulations when both dark matter and normal matter are present in the universe. “As stars are born and die, they explode into supernovae, which can shape the centers of galaxies, naturally explaining the existence of these features,” said co-author Jorge Moreno, associate professor of physics and astronomy at Pomona College. “Simply put, the features we examined in observations require both the existence of dark matter and the incorporation of normal-matter physics.”

The researchers expect their findings to spark debate within the scientific community but believe there may be room for common ground. The next step, according to Mercado, is to see if the dark matter model remains consistent across a dark matter universe and to potentially use this relationship to distinguish between different dark matter models.

Keyword/phrase: dark matter existence simulations

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