Re: more careless assertions

Posted by Pasti on Mar 25, 2002 at 03:24
(64.10.121.76)

Re: more careless assertions (Paul)

"you show me an article on the formation of a black hole or the reasons there are black holes if you can find one that does not include density as "the major reason" that there are black holes and then I might believe cougar was right and I was wrong."

That's easy.Remember?I work in quantum gravitation.The subject of collapse and black holes is traditional in GR,so I the best books on the subject are:
a.Weinberg,"Gravitation and Cosmology:principles..."
b.Wald, "General relativity";see chapters 6 for the Schwarzschild solution, and 9 for singularities.
c.In the case you really want a technical article on the subject,Carlip's review "The (2+1)-dimensional black-hole",gr-qc/9506079 (http://www.arxiv.org) is a good review in 3 dimensions for the generalization of the Reissner-Nordstrom black-hole to include spin.

First get through these refs, and I will give you more, if you wish.

"1) gravity causes matter to compress --> matter gets denser."

True, but this refers only to the collapsing matter, not to distant objects.

"2) this denser matter then has a stronger gravity,"

Only inside the dust cloud (see my last posting with the collapsing dust model);outside the cloud, your statement is not true in within this model(and if you don't agree with the model, try to remember that the universe is made of matter and very large voids, so the assumption of a collapsing dust cloud of finite size is not unreasonable).


"as the matter compresses onto itself the gravity normally associated with this mass gets stronger and stronger."

Nope.It remains esentially the same.Even multipolar corrections in the case of non-spherical symmetry does not produce the effects you are talking about,when it comes to the "outside" and far from the collapsing cloud.

"3) this strenghtening of gravity causes even more matter in the vicinity to be drawn into the forming black hole."

Nope.The "strengthening of gravity" takes place only for the cloud.Distnat object will be attracted to the cloud by the "regular gravity" of the cloud's mass,irrespective of its density. And not all matter in the vicinity must end up exclusively in the collapsing cloud, even if the black-hole is already formed.There still is matter (light for example)at sufficiently high energy that will only be scattered by the cloud/black-hole.

"4) gravity becomes so strong that light can not escape the formed black hole."

Nope.This is an incorrect view of what is happening.Remember, the viewpoint you must take in GR is different from the classical viwpoint of physics, and YOU MUST MAKE THIS DIFFERENCE in order to correctly address problems in GR.
After the black-hole formation,the causal structure/geometry of the spacetime (i.e. the presence of a horizon, generally speaking)will not allow signals to escape the event horizon.While this is true,the collapsing mass inside the horizon (or Schwarzschild radius, if you prefer it better)can have a finite size (of course, smaller than the horizon)can emit photons, or light signals, but these signals/photons will never escape the event horizon, i.e. no one will be able to receive them.
This is qualitatively different from what you say, since you refer to the gravitational force between the particles of collapsing matter, and this is related to the combined effects of matter and gravitational interaction, if you like it better this way.

"until then I will stick to what I have learned in the past"
Paul,learning involves two main processes:
1.acquiring the relevant information, which has become a rather trivial task nowdays.
2.understanding the info you got.
You seem to have serious problems with the second process,and your stubborness only prevents you from accomplishing it.

Or,if you like it more this way, when two people tell you that you are drunk, you go to sleep.If several people tell you that you are drunk,you ask someone to get you to your bed.If you continue pretending that you are not drunk, you will sleep on the floor.

Follow Ups:


Post a Followup

Name:
E-Mail:

Subject:
Comments:

[ Forum ] [ New Message ]