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I remember in either the Pioneer or the Voyager flyby, they discovered that Saturn's rings have spokes. The radial features turned out to be dust and static electricity, but seeing the apparently impossible in front of you is disconcerting. I remember feeling quite distressed about the bars in in galaxies when I was in 8th grade.

Did astronomers say, "There's something happening in galaxies that's definitely impossible and we have no explanation?"

Or what?

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    $\begingroup$ "Invented" might not be the best term to use in the title IMO; it more than hits that DM isn't real. Can I suggest "hypothesised" as a more neutral term? $\endgroup$
    – ScienceSnake
    Commented Sep 4 at 19:22
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    $\begingroup$ Why do you think bars are impossible without dark matter? What evidence do you have that any astronomers thought that? $\endgroup$
    – Peter Erwin
    Commented Sep 5 at 3:43
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    $\begingroup$ @PeterErwin is there another mechanism? That's my question. $\endgroup$
    – Miss_Understands
    Commented Sep 5 at 12:46
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    $\begingroup$ Theoretical arguments and $N$-body simulations suggested that rotating galaxy disks were intrinsically gravitationally unstable and naturally formed perturbations like spiral arms and (often) bars. One of the persistent questions is actually "why don't all galaxy disks have bars?" In the 1980s it was suggested that sufficiently massive round halos (e.g., dark-matter halos) would prevent bar formation. More detailed simulations in the early 2000s showed this wasn't necessarily true. $\endgroup$
    – Peter Erwin
    Commented Sep 5 at 15:28

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