The stars in the outer fringes of the Milky Way move too slowly. A research team reaches conclusions about the center of the galaxy.
CAMBRIDGE – Like most galaxies in the universe, the Milky Way galaxy spins like water in a vortex. The rotation is driven in part by the matter in the galactic disk — but not only. As early as the 1970s, research discovered that the rotation of galaxies could not be explained solely by visible matter, and researcher Vera Rubin was among the first to discover evidence of the existence of dark matter.
Stars in the Milky Way are behaving strangely
Dark matter, which has not yet been clearly discovered, appears to ensure that the stars within the galaxy all have the same speed, and does not decrease with distance. Invisible dark matter appears to give distant stars a “boost,” according to the theory. But what is it like in our Milky Way Galaxy? A research team from the Massachusetts Institute of Technology (MIT) has measured the speed of stars in the Milky Way and has come up with interesting new results.
“It turns out that it is difficult to measure the rotation curve when you are inside a galaxy,” Xiaowei says in one of the articles. notice. Ou is one of the authors of the study published in the journal Monthly Notices of the Royal Astronomical Society published had become.
At the edge of the Milky Way, the movement of stars slows down. Does this have anything to do with dark matter?
Using data from the European Gaia spacecraft and the ground-based Apogee programme, the research team determined the distances of more than 33,000 stars in the Milky Way. This led to a three-dimensional map showing the distribution of stars in the Milky Way. The team then created a rotation curve that showed how fast stars were moving at a given distance from the galactic center. “This is where the weirdness started,” recalls co-author Lina Naguib, a physics professor at MIT.
“What really surprised us was that this curve remained flat, flat, flat up to a certain distance, and then it started to decline,” the researcher said. “This means that the outer stars are rotating a little slower than expected, which is a very surprising result.”
“The result is in coherence with other measurements.”
Instead of seeing a slight decline like previous turnover curves, the curve ended up falling more steeply than expected. Using the new rotation curve, the research team was able to recalculate the distribution of dark matter in the Milky Way to understand how exostars could be moving more slowly than they should.
Indeed: The result showed that the Milky Way appears to have a lighter core than previously assumed. The center of our galaxy could be less dense and contain less dark matter than expected. “This result contradicts other measurements,” explains Najeeb. “There's something fishy out there somewhere, and it's very interesting to find out where that is in order to get a coherent image of the Milky Way.”
Exploration of the Milky Way continues
In further research, the team now wants to find answers to the questions raised by the study. “Really understanding this finding will have profound implications,” Najib asserts. “This could lead us to find more hidden masses beyond the edge of the galactic disk or make us rethink the state of equilibrium in our galaxy.”
Recently, another research team showed that the Milky Way Galaxy looks very different than previously thought. It is not only the Milky Way galaxy that surprises researchers, but there is another galaxy that also arouses astonishment. (unpaid bill)
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