Dark Matter = Black Holes?

[Daymare17]

From what I gather (from Wikipedia ) the main (and first) evidence for the existence of dark matter was gathered by measuring the light emitted from galaxies compared with their rotational speed. There was so little visible matter in the galaxies that with their high spin rate, they should not stick together but fly apart from centrifugal force, according to standard theories of gravitation.

 

Well my theory is that the dark matter is simply black holes. We have strong evidence that massive black holes exist at the center of our Galaxy and others. They are invisible, and they are what holds the galaxies together. Any cosmologists here that can check my theory?

[[Tycho?]]

Large masses, like galaxy-sized black holes can be ruled out on the basis of gravitational lensing data.

 

From that wikipedia article.

 

Basically black holes are gravitationally powerful, and these gravitational effects are concentrated enough that they can be observed via their influence on light (gravitational lensing) or their influence on matter near them (one would observe matter orbiting what seems to be nothing). These are not observed in large enough quantities to account for Dark matter. Dark matter seems to be more uniform.

 

Read more of that article for current ideas on what dark matter may actually be.

[Kermit]

It's sad we'd never be able to see what this dark matter is in our lifetimes, though. I mean, going up to it and touching it or whatever.

 

What if it turns out, though, that dark matter is really where Jimmy Hoffa was all along? Like in some huge dark spaceship we can't see. Damn you, Jimmy Hoffa. Damn you.

[TwistOfCain]

From what I gather (from Wikipedia ) the main (and first) evidence for the existence of dark matter was gathered by measuring the light emitted from galaxies compared with their rotational speed. There was so little visible matter in the galaxies that with their high spin rate' date=' they should not stick together but fly apart from centrifugal force, according to standard theories of gravitation.

 

Well my theory is that the dark matter is simply black holes. We have strong evidence that massive black holes exist at the center of our Galaxy and others. They are invisible, and they are what holds the galaxies together. Any cosmologists here that can check my theory?[/quote']

 

 

I have to disagree. Light, being made of particles, is trapped in a black holes gravitational pull. In that sense, the reverse would have to be true for darkness. It'd have to be made of particles, and therefore be trapped in light. (If anyone has ever read Discover magazine, read anything you can find on "gravity" waves if two black holes were to collide.) Is darkness a particle form? I'd say it's not, only because it doesn't move. Darkness is merely an absense of light. (I could EASILY be very wrong, so excuse me if I am.) Anyone care to correct me?

[gmacrider]

Well my theory is that the dark matter is simply black holes. We have strong evidence that massive black holes exist at the center of our Galaxy and others. They are invisible, and they are what holds the galaxies together. Any cosmologists here that can check my theory?

Your theory may run into problems because it conflicts with the apparent DISTRIBUTION of the dark matter. Measurements indicate the missing matter is spread throughout a huge dark halo much larger than the visible halo of typical whirlpool galaxies. There should be about TWICE as much galactic mass OUTSIDE of the visible halo compared to what's inside it. So more black holes within the visible halo would be in the wrong location to explain the missing mass. Could there be a huge number of smaller black holes distributed in a large halo surrounding a galaxy? I'm not sure about that question, but I suspect there would be a problem explaining how such black holes would have evolved.

[luc]

From what I gather (from Wikipedia ) the main (and first) evidence for the existence of dark matter was gathered by measuring the light emitted from galaxies compared with their rotational speed. There was so little visible matter in the galaxies that with their high spin rate' date=' they should not stick together but fly apart from centrifugal force, according to standard theories of gravitation.

 

Well my theory is that the dark matter is simply black holes. We have strong evidence that massive black holes exist at the center of our Galaxy and others. They are invisible, and they are what holds the galaxies together. Any cosmologists here that can check my theory?[/quote']

 

 

No, the first evidence for DM came from the observation by Zwicky of the movement of galaxies in the Coma cluster. He observed galaxies moving so fast that ought to have escaped the cluster, so he suggested the existence of some unseen matter that was holding the cluster together