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Scientists at Case Western Reserve University have found new evidence that could change our understanding of the cosmos. Tobias Mistele, a post-doctoral scholar at the Department of Astronomy, used gravitational lensing to investigate dark matter. He discovered that the rotation curves of galaxies remain flat for millions of light years.
Previously, it was believed that these curves must d by Clarence Oxford
Los Angeles CA (SPX) Jun 18, 2024
Scientists at Case Western Reserve University have found new evidence that could change our understanding of the cosmos. Tobias Mistele, a post-doctoral scholar at the Department of Astronomy, used gravitational lensing to investigate dark matter. He discovered that the rotation curves of galaxies remain flat for millions of light years.
Previously, it was believed that these curves must decline over distance. According to Newtonian gravity, stars at the outer edges of galaxies should move slower due to weaker gravitational pull. This discrepancy led to the dark matter theory, but even dark matter halos should end eventually. Mistele's analysis shows that this is not the case, suggesting that the influence of dark matter extends far beyond previous estimates.
"This finding challenges existing models," he said, "suggesting there exist either vastly extended dark matter halos or that we need to fundamentally reevaluate our understanding of gravitational theory."
Stacy McGaugh, professor and director of the Department of Astronomy, said Mistele's findings, soon to be published in the Astrophysical Journal Letters, push traditional boundaries. "The implications of this discovery are profound," McGaugh said. "It could redefine our understanding of dark matter and prompt us to explore alternative theories of gravity."
Mistele used gravitational lensing, a phenomenon predicted by Einstein's general relativity, to plot the Tully-Fisher relation, which shows the relationship between the visible mass of a galaxy and its rotation speed. "We knew this relationship existed," Mistele said. "But it wasn't obvious that the relationship would hold the farther you go out. How far does this behavior persist? That's the question, because it can't persist forever."
Mistele emphasized the need for further exploration and collaboration within the scientific community. McGaugh noted the ongoing, yet unsuccessful, efforts to detect dark matter particles. "Either dark matter halos are much bigger than we expected, or the whole paradigm is wrong," McGaugh said. "The theory that predicted this behavior is the modified gravity theory MOND, proposed by Moti Milgrom in 1983 as an alternative to dark matter. This result may point to a new theory of gravity beyond what Einstein taught us."
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Department of Astronomy at Case Western Reserve's College of Arts and Sciences,
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