black holes and GR

[CPL.Luke]

well from what Ive read about black holes is that in them the space time curvature is infinite, because the black hole itself is in fact a singularity so it has infinite density

 

so wouldn't one of the implications of this be that all point particles are in fact black holes?

[T-77]

ya hmm agree about black holes theory only thing is that if black holes are so powerfull how all sciaentis agree that black hole traveling true the space might take apart any subject that will arive close enought acording to black holes gravity.

So meaning that black holes can take apart a sun or planet or entire galaxy!

How human would control such power to use for traveling true the black holes? that is big question. My opinion? I would not play with suche power to use for time traveling. But the other hand for 100% agree with you on that that if black holes exist like they do acording to latest fact> black holes might be the kay to open mystery behind the time and others dimension exist around us.

 

PS: Sory for my engl.

[CPL.Luke]

I think a point particle could go by without tearing apart the planet because its mass is so small.

[T-77]

I think a point particle could go by without tearing apart the planet because its mass is so small.

 

 

 

But to be able to send such particle to somwere the black hole would have to be created. And that mean that even if you would create lat's say small black hole that would be safe enough to (if you will) operate. Than with every feed of the particle the black hole energy would grow stronger otherwise if you would be able to cotrol even that than you got Bingo?

 

Just opinion .

[CPL.Luke]

I as thinking more along the lines of a particle like an electron could be considered a black hole as it supposedly is a point particle (unless this has recently changed).

 

it was more of a thought into whether that is true or not.

[[Tycho?]]

I as thinking more along the lines of a particle like an electron could be considered a black hole as it supposedly is a point particle (unless this has recently changed).

 

it was more of a thought into whether that is true or not.

 

 

I did a brief check, got this:

http://www.physlink.com/Education/AskExperts/ae191.cfm

 

If you do a google search for "electron size" you get numerous results with your exact question being asked. Also, it is not know if the electron is truely a point particle, only that its smaller than we can measure, and it can be treated as a point for experimental purposes.

[CPL.Luke]

maybe someone could help me understand that article a bit more, when the particle collapses is it a point particle at that moment or, do I not understand this correctly

[revprez]

well from what Ive read about black holes is that in them the space time curvature is infinite' date=' because the black hole itself is in fact a singularity so it has infinite density

 

so wouldn't one of the implications of this be that all point particles are in fact black holes?[/quote']

 

The asymptoptic behavior of GR's description of black holes is a consequence of a continuous limit inherent to theory. There's no reason to expect that this pecular math translates into a physical reality.

 

Rev Prez

[CPL.Luke]

well to my knowledge no one has claimed that black holes are not singularities, so if a true point particle existed then woudn't it also be considered a black hole?

[fuhrerkeebs]

We don't know yet, we have to wait for a good, reliable theory of quantum gravity.

[YT2095]

Do "Black holes" get smaller or bigger the more matter they consume?

[Martin]

Do "Black holes" get smaller or bigger the more matter they consume?

 

the radius of the event horizon increases as the hole consumes more matter

 

for an ordinary solar mass hole, the schwarzschild radius (radius of event horizon) is about 3 kilometers

 

the schw. radius is proportional to the mass, so if you added some matter to make it 2 solarmasses

then the radius would be 6 kilometers

 

ordinary means approx. electrically neutral and not rotating so fast that the event horizon becomes noticeably oblate----ordinary nonrotating holes have spherical EH, how everybody pictures a black hole---so lets not think about the rotating kind---it make the idea of radius more complicated

[Martin]

well to my knowledge no one has claimed that black holes are not singularities,...

 

We don't know yet, we have to wait for a good, reliable theory of quantum gravity.

 

Keebs is right!

 

In fact a some recent papers in Loop quantum gravity show that the singularity in the classical picture of black hole is just a fault of the classical Gen Rel theory. If you quantize Gen Rel then you get a better picture and the classical singularities go away. there is no infinite curvature or infinite density. In the quantized version the curvature and density reach a max

 

here's a sample of a recent paper about it

http://arxiv.org/abs/gr-qc/0410125

 

Two papers already posted about this, one by L. Modesto and one by

V. Husain and O. Winkler. Also a talk is online by Abhay Ashtekar about it. Also there is a paper by Bojowald and Ashtekar in the works but not posted yet. The removal of the former classical singularity is an exciting question now and one issue is what is there instead? the curvature does NOT blow up to infinity. what happens? does spacetime balloon out somewhere else?

 

I think Keebs is saying wait and see. it is a good attitude. the stuff is too new to form definite ideas about. more like just something to watch.

[CPL.Luke]

my personnal oppinion is that its good to think about it even if your totally wrong, at least youll have ideas in your head for when you get out of school.

 

however out of curiosity, in order for no light to escape a black hole (even if its path is perpendicular to the "singularity") wouldn't the space time curbature need to be infinite.

 

well anyway, I'm off to read that paper now

[YT2095]

Thanks Martin, great answer

 

and I can see how the swirly ones would make things a little more difficult

[[Tycho?]]

my personnal oppinion is that its good to think about it even if your totally wrong' date=' at least youll have ideas in your head for when you get out of school.

 

however out of curiosity, in order for no light to escape a black hole (even if its path is perpendicular to the "singularity") wouldn't the space time curbature need to be infinite.

 

well anyway, I'm off to read that paper now[/quote']

 

No I dont think its a requirement. Space time curvature does not have to be infinite, it just has to be sufficiently large to prevent light from escaping. Its not like the event horizon of a black hole is a line where on one side curvature is infinite and on the other side its not. Its just the point where light is "trapped", meaning not escaping, but not falling in either. If you go futher in from the event horizon curvature would increase until you reach the singularity itself, where it is infinite.

[cyeokpeng]

well from what Ive read about black holes is that in them the space time curvature is infinite' date=' because the black hole itself is in fact a singularity so it has infinite density

 

so wouldn't one of the implications of this be that all point particles are in fact black holes?[/quote']

 

 

A point particle is a Physics trick of Newtonian mechanics to describe the motion of a particle as if all its mass is concentrated at its centre point (centre of mass). However, the actual object that is moving is not a point, but a sphere or any other shape. It has finite volume, and hence it is essentially NOT a black hole.