Space

Astronomers Suspect That Dark Matter Is More Fuzzy Than Cold

Sam D
First Posted: May 01, 2017 05:40 AM EDT

Scientists have recently conducted a study to explore the possibility that dark matter may be more fuzzy than cold, adding to the mysterious and invisible substance’s complexity. A team of astronomers used data obtained from NASA's Chandra X-ray Observatory, which involved 13 galactic clusters, to analyze the cosmic conundrum’s properties.

Since the past many decades, scientists have been trying to comprehend the detailed properties of dark matter. The most popular theory assumes that dark matter is a particle much bigger in size than a proton that is "cold," indicating that it moves at speeds much smaller than light’s speed. Though this model has successfully explained the universe’s structure on very large scales, it has shortcomings explaining matter distribution on the smaller scale of galaxies. Another problem with the cold dark matter model is that it predicts a much higher number of small galaxies that orbit around galaxies like the Milky Way than scientists actually see.

To address the shortcomings of the cold dark matter model, researchers have developed alternative models where dark matter has very different properties -- one of which is the fuzzy dark matter model. This simple model has successfully explained the location and amount of dark matter in small galaxies.

A more complicated model of fuzzy dark matter has been needed for larger galaxies. According to this model, huge dark matter concentrations can result in multiple quantum states (excited states), in which the dark matter particles can have varied energy amounts, similar to an atom with electrons in higher energy orbits. These quantum states alter how dark matter density differs with distance away from the galaxy cluster’s center.

In the new study that has been published in the Monthly Notices of the Royal Astronomical Society, the team of scientists used the Chandra observations to observe if the fuzzy dark matter model is applicable at larger scales than that of galaxies. The Chandra data was used to approximate "both the dark matter amount in each cluster and how the density of this matter varies with distance away from the center of the galaxy cluster."

Based on their observations, the scientists found the model where the particles had different energy amounts -- the multiple quantum states -- did give good agreement with the data. In fact, according to a Deccan Chronicle report, “the fuzzy dark matter model may match the observations of these 13 galaxy clusters just as well or even better than a model based on cold dark matter.” The result indicates that the fuzzy dark matter model may be a practical alternative to cold dark matter. However, further study is needed to test this possibility.

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