The super massive black hole at the centre of Milky Way has a mass of about 4 million times that of our sun. Is this enough to keep the entire galaxy together, is it this black hole which keeps the galaxy together? I did read that there are also galaxies that don't have a super massive blackhole, what keeps those galaxies together?

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    $\begingroup$ I’m voting to close this question because it belongs either on Astronomy stack exchange or Physics stack exchange. (But the answer is: the mutual gravitation of the stars in the galaxy, even in galaxies with SMBHs, since SMBHs are a very small proportion of the mass of most galaxies: certainly of ours). $\endgroup$ – tfb Feb 28 at 13:24
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    $\begingroup$ Could someone transfer this question to the right place? $\endgroup$ – O S Feb 28 at 13:28
  • $\begingroup$ I don't have the power to do that I think (or at least I don't know how): sorry! $\endgroup$ – tfb Feb 28 at 13:36
  • $\begingroup$ It's a good question but I’m voting to close this question because it is off-topic here, not about Space Exploration as defined in the help center. Luckily however it's 100% on-topic in Astronomy SE and possibly Physics SE, so I hope it will be migrated soon and find a new home :-) $\endgroup$ – uhoh Feb 28 at 13:52
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    $\begingroup$ @StarfishPrime now I've had to remove the flag because the OP went ahead and cross-posted to Astronomy $\endgroup$ – uhoh Mar 1 at 2:15

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