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posted by janrinok on Friday March 30 2018, @09:39PM   Printer-friendly
from the Now-you-see-it-now-you-don't-because-it's-dark? dept.

A galaxy has been found containing no dark matter, but that proves dark matter is real?

A distant galaxy that appears completely devoid of dark matter has baffled astronomers and deepened the mystery of the universe's most elusive substance.

[...] In the Milky Way there is about 30 times more dark matter than normal matter. The latest observations focused on an ultra-diffuse galaxy – ghostly galaxies that are large but have hardly any stars – called NGC 1052-DF2.

The team tracked the motions of 10 bright star clusters and found that they were travelling way below the velocities expected. "They basically look like they're standing still," said van Dokkum.

The velocities gave an upper estimate for the galactic mass of 400 times lower than expected. "If there is any dark matter at all, it's very little," van Dokkum explained. "The stars in the galaxy can account for all of the mass, and there doesn't seem to be any room for dark matter."

Paradoxically, the authors said the discovery of a galaxy without dark matter counts as evidence that it probably does exist. A competing explanation for the fast-orbiting stars is that the way gravity drops off with distance has been misunderstood – but if this were the case, all galaxies should follow the same pattern.

https://www.theguardian.com/science/2018/mar/28/galaxy-without-any-dark-matter-baffles-astronomers. The findings are published in the journal Nature.


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  • (Score: 3, Interesting) by wonkey_monkey on Sunday April 01 2018, @10:56AM

    by wonkey_monkey (279) on Sunday April 01 2018, @10:56AM (#661105) Homepage

    We never had to "figure out how EM wave propagate without medium" because the concept never even occured to anyone. What we had to figure out was how the speed of light could remain constant, and to do that, we had to discard the notion of ether.

    We'll discard the notion of dark matter if (and that's a huge if) it ever turns out to be incompatible with observation, but the chances of that - given the existence of the Bullet Cluster and this new discovery - are getting slimmer all the time.

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    systemd is Roko's Basilisk
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