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View Full Version : Is dark matter linked to black holes?



MVAgusta1078RR
2013-Nov-28, 08:06 AM
Since dark matter surrounds galaxies and accounts for the missing mass but black holes have a correlation with the size of the galaxy. The bigger the supermassive black hole the bigger the galaxy. Is the singularity of the black hole making that extra pull? Is it making some kind of energy like extra gravity we're not aware of since we don't fully understand black holes?

tusenfem
2013-Nov-28, 11:51 AM
There is no "singularity" which might create "extra gravity". The singularity is a mathematical artifact.
A black hole just has its mass and corresponding gravitational pull.
That bigger galaxies have bigger central black holes is just because there was more mass at the beginning.

By the way, welcome to CQ.

Shaula
2013-Nov-28, 04:43 PM
The issue is that gravity does not appear to fall off in a way that is consistent with an inverse square law and a central mass. So it does not really matter how heavy you make the black hole - it cannot replicate the rotation curves we see. you'd have to posit a different field witha different distance behaviour - and then you are into MOND territory. So far MOND has struggled to match observations.

Also there are glaxies without black holes, I am not aware that they have been shown to be dark matter poor (which would equate to no black hole gravitational effects in your idea)

TooMany
2013-Nov-28, 09:40 PM
So far MOND has struggled to match observations.


An alternate theory, CDM, has struggled to detect any cold dark matter particles to match observations. As far as I know, MOND has been quite successful at predicting galactic rotation curves in detail based only on visible matter.

WayneFrancis
2013-Nov-29, 02:34 AM
An alternate theory, CDM, has struggled to detect any cold dark matter particles to match observations. As far as I know, MOND has been quite successful at predicting galactic rotation curves in detail based only on visible matter.

How does MOND explain gravitational lensing? Seems that CDM is still a better fit since it covers both rotation curve and lensing. CDM also works with the idea of virtual photons as the carrier of gravity doesn't it?

tusenfem
2013-Nov-29, 06:19 AM
Okay, stop it right there, STAY ON TOPIC.