Do super massive black holes have the gravitational power to rotate spiral galaxies???

Question

Thanks for your answer...Tom Science 4

Answer 1

Not really. The logic runs largely in the opposite direction:

Spiral galaxies inherit their angular momemtum from the gas from which they originally formed. When super massive black holes form at the centre of such spiral galaxies, they too inherit the angular momentum that they will possess from the swirling material near the centre of such galaxies. So the logic runs:

Swirling galactic material --> central rotating super massive black hole.

It's true that rapidly rotating central super massive black holes will drag spacetime around them in their own vicinity. However, that effect drops off quite rapidly with distance from the black hole, and becomes far too weak an effect to account for the rotation of the bulk of the original galaxy.

This effect is not unlike the following:

Imagine a rotating sphere or cylinder immersed in a tub of very viscous molasses. As it rotates, viscous forces will rotate the molasses in contact with the central object at almost its own rotational speed; but as one considers rings of molasses successively further and further away, the rotation induced will get slower and slower. Like all analogies, this has its drawbacks, but it gives some feel for the effects that happen near central super massive black holes.

Good question, though; live long and prosper.

Answer 2

The others are right in the fact that the black hole does not cause the rotation of the objects around it. Rather the gravity produced is the force which attracts the bodies in the galaxy to it. Now, because the speed of the orbiting objects is dependant on the strength of the gravity, it is possible to infer the mass of the black hole by measuring the speed of the stars close to it. As distance to the black hole increases the gravity felt by other objects decreases as a function of the square of the distance. So if the mass of the central black hole is known it is possible to predict the speed of orbit for objects in a galaxy based on their distance from the center of the galaxy. However it has been discovered that the predictions don't hold up. The stars are orbiting way too fast on the outside edges of galaxies. There appears to be much more mass present in galaxies than previously thought. Scientists, having exhausted all possibilities of what that might be (and yes, they have thought of dust, gas, and things that don't give off light) have come up with "Dark Matter". Dark matter is believed to make up the necessary mass to account for the orbital velocities seen by the stars in galaxies.

So to answer your questions as I understand it. No, massive black holes are not massive enough to account for the orbital speeds of the stars that make up galaxies.

Answer 3

I'm inclined to think so. Look at the way water spirals when it's getting flushed down the sh*t-hole. Look at the way a galaxy spirals when it's getting sucked into its central black hole. If that isn't enough to convince everybody that we're getting flushed down the cosmic crapper, then I don't know what is.

Next question is, what do we DO about it?

4 JAN 07, 0542 hrs, GMT.

Answer 4

I am under the opinion that at the center of every galaxy is a black hole. The black hole itself doesn't rotate the matter about them. It is the curved space caused by the mass of the black hole that actually rotates the matter around them.

Answer 5

My allian friend sais YES .

Answer 6

I would say it probably has something to do with it.