Mysterious fast radio bursts helped detect missing matter in the universe, study says -... - 0 views
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Mysterious fast radio bursts have been used to unlock another strange aspect of the universe: the case of the "missing matter."
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Astronomers have yet to determine what causes these fast radio bursts, which are unpredictable but can be spotted and traced back to their origin using sensitive telescopes.
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Normal matter, called baryonic matter in this study, is made of the protons and neutrons that comprise both humans and star stuff. But astronomers could only account for about half of it that should exist in the universe.
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Unaccounted for, this missing matter was predicted to exist, but hard to find. In fact, astronomers have been searching for it over the last 30 years, the researchers said. Measurements of the Big Bang show how much matter was present in the early days of the universe, suggesting its existence.
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"It turned out that it was hiding in a density so low that it does not emit light, it doesn't absorb it, and it doesn't reflect it," he said.
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"The radiation from fast radio bursts gets spread out by the missing matter in the same way that you see the colors of sunlight being separated in a prism," Macquart said.
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"Their millisecond durations made it very easy to measure the effect of dispersion — the process by which their longer wavelength emission is delayed with respect to their shorter wavelength emission is delayed — and hence to measure exactly how much matter they have encountered on their multi-billion year intergalactic journeys to Earth," Macquart said.
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Astronomers were able to pin down the source of a repeating fast radio burst in 2017. But single radio bursts are harder to pinpoint because they don't reoccur.
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"ASKAP both has a wide field of view, about 60 times the size of the full Moon, and can image in high resolution," said Ryan Shannon, study coauthor and associate professor at Swinburne University of Technology, in a statement. "This means that we can catch the bursts with relative ease and then pinpoint locations to their host galaxies with incredible precision.
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"We've discovered the equivalent of the Hubble-Lemaître Law for galaxies, only for fast radio bursts," Macquart said. "The Hubble-Lemaître Law, which says the more distant a galaxy from us, the faster it is moving away from us, underpins all measurements of galaxies at cosmological distances."