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hemkant
2006-Sep-03, 06:40 PM
Well these are the questions a guy asked me and i am very confused....
Maybe you people could help me...

Here you go with the questions

Hi everyone!
I was pondering over this question for a long time so please put in your answers/suggestions and help me get a conclusion.Iíve divided the question into 3 parts as each successive question depends on your previous answer.

1.1 Are black holes stationary? Why/why not?

1.2 (Depends of your answer of que 1.1) And if black holes are stationary, then we know that the galaxies are moving apart or we can say that the universe is proceeding towards the Big Crunch, so my question is that Ė where will the black holes be or go?

Let us assume that we have a galaxy say G1 and a black hole in our present space time grid. Now, we say that as the universe is expanding, G1 is moving with a certain speed.So, after some time as the G1 moves towards big crunch, what will happen then? Will the black hole remain there if you say it stationary? But, if we take big bang as singularity of one wormhole and big crunch as a singularity of another one,then we can deduce that the G1 is moving towards another wormhole, so will the black hole vanish, if not then what about the space time grid???
(Iím very confused with this! I might have left some loop holes, so please do correct me )

1.3 AND FINALLY, If the black holes are not stationary and are in motion in some respect, then what effect will this create in the space time grid as it is embedded in it? Will it create some sort of wrinkles/distortions or what???

I'm waiting for the answers...............!!!

Jeff Root
2006-Sep-03, 08:10 PM
1.1 Are black holes stationary? Why/why not?
Stationary? Relative to what?

Things move relative to one another. Black holes are no
different from anything else in that regard. A stellar-mass
black hole in a galaxy orbits the center of the galaxy.



1.3 AND FINALLY, If the black holes are not stationary and are
in motion in some respect, then what effect will this create in
the space time grid as it is embedded in it? Will it create
some sort of wrinkles/distortions or what???
No. Accelerating a large mass might create gravitational
waves, but simple motion would have no effect. Search for
the term "LIGO" (Laser Interferometer Gravitational-Wave
Observatory).

-- Jeff, in Minneapolis

antoniseb
2006-Sep-03, 08:15 PM
Hi Hemkant, welcome to the BAUT forum.

Jeff's answers are little different from the ones that I would give. We believe we have observed two black holes orbiting each other. I suppose you could contrive some coordinate system in which both are stationary, but it wouldn't be useful for most ways of thinking about the universe that we've developed so far.

Ken G
2006-Sep-03, 11:34 PM
Indeed, it is thought that virtually all galaxies harbor supermassive black holes, and they must move with their host galaxies.

Van Rijn
2006-Sep-04, 03:57 AM
1.2 (Depends of your answer of que 1.1) And if black holes are stationary, then we know that the galaxies are moving apart or we can say that the universe is proceeding towards the Big Crunch, so my question is that Ė where will the black holes be or go?


Of course, black holes aren't stationary, and we don't believe there will be a "big crunch." We expect that things will continue to spread out. In answer to your question, though, in the fullness of time (a very long time from now) we expect that black holes will evaporate through Hawking radiation.