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rahuldandekar
2004-Feb-21, 06:01 AM
Suppose the universe s expanding forever. THen, after much time, there will be only black holes. Suppose these black holes come in contact with each other, and form the ultimate black hole, with all the matter that once formed the universe. Then, it starts to give away its mass, as told by Stephen Hawking.

And it the end, it will explode with a bang (probably, as that is assumed). Could this be equal to a big bang?

devilmech
2004-Feb-21, 11:46 AM
Theoretically, if all the matter in the universe was drawn into a single black hole, which then exploded and expelled all it&#39;s matter again, this would indeed equal the big bang simply due to the fact that the big bang is responsible for all the matter currently known to be in the universe.

galaxygirl
2004-Feb-22, 01:01 AM
If black holes can only take in material that is close to their event horizon, then how can black holes combine to become one giant one (and eventually take in all the matter in the universe)?

NasaBoy
2004-Feb-22, 05:41 AM
Also, another problem with that, is that stars are being created all the time, and it just doesn&#39;t seem possible for all stars to become black holes because of that, also the size of the universe, and because not all stars are going to become black holes. Its a very interesting theory, but it just doesn&#39;t seem possible.

rahuldandekar
2004-Feb-23, 06:22 AM
You know, the black holes could come closer to each other and enmvelop themselves.
And as all stars start burning heavier fuels, after trillions of years all that would be left of the universe would be black holes.

devilmech
2004-Feb-23, 08:27 AM
Originally posted by galaxygirl@Feb 22 2004, 01:01 AM
If black holes can only take in material that is close to their event horizon, then how can black holes combine to become one giant one (and eventually take in all the matter in the universe)?
In reality, it&#39;s currently an impossibility due to the practical limits of gravitation. It is however, theoretically possible that such a thing could happen, and it can&#39;t be ruled out.

Faulkner
2004-Feb-23, 09:32 AM
Why does the Universe have to be "empty" to be considered a "black hole"? The speed-of-light constant (I think) reinforces the idea that we&#39;re INSIDE an event horizon...It&#39;s almost "intuitive"...&#33;? It is, after all, the "Speed Of Lght" that keeps uss away from the boundaries of the Cosmos, and here we are (monkeys) wondering if we can go faster than the speed of light...when it&#39;s PHYSICALLY impossible&#33;

The only real thing that Einstein said about intergalactic travel, was that it can be done easily, as long as it&#39;s a one-way trip... For the astronaut, it could be just a few months to Andromeda Galaxy...but he or she could never return, except to an Earth a few million years older.

I VOLUNTEER&#33;&#33;&#33;

lazserus
2004-Feb-24, 10:11 PM
And as all stars start burning heavier fuels, after trillions of years all that would be left of the universe would be black holes.
This isn&#39;t true. Not all stars will begin burning the heavier elements. There will always be a wide variety of stars. The size of a star generally depends on the environment it was incubated in.

I see what you&#39;re getting at, Faulkner, but I don&#39;t see how this would support the idea that our universe exists within the boundaries of some primordial super black hole. The escape velocity of an event horizon is significantly higher than c, but as far as we can see, light doesn&#39;t have any problems getting anywhere in the known universe. We should, technically, be able to observe a form of "boundary" where light can not escape. This is also assuming that light doesn&#39;t act differently within the Schwarzchild radius.

PiggyGirl1
2009-Dec-03, 02:48 AM
Hi how are you? I agree with you Lazserus. Can you answer a quick question for me? Do you know about stars and the universe, and the question is that is it possible for a big rip to happen in our universe and if yes when will it take effect? Please be honset. From PiggyGirl1

01101001
2009-Dec-03, 02:53 AM
Welcome to BAUT Forum.

I agree with you Lazserus. Can you answer a quick question for me?

Shh, Lazserus might be sleeping. That was from back in 2004. And Lazserus hasn't posted since.

Do you know about stars and the universe, and the question is that is it possible for a big rip to happen in our universe and if yes when will it take effect?

But maybe someone else will explain why a big rip isn't much to worry about.

Like cosmologist Sean Carroll (http://preposterousuniverse.blogspot.com/2004/03/big-rip.html):

[...] The truth is, we can't predict the future of the universe with any reliability at all until we understand much more about the underlying physics of the dark energy. If it is increasing, it might only do so temporarily, before leveling off to a constant value (see my paper with Hoffman and Trodden). If it's currently a constant, it may decay completely away in the future. So, the choice between Crunch, Fizzle, and Rip is one we have no way to decide between right now. (But "Crunch, Fizzle, and Rip" is a great name for a band, or maybe a law firm.)

WayneFrancis
2009-Dec-03, 03:40 AM
Suppose the universe s expanding forever. THen, after much time, there will be only black holes. Suppose these black holes come in contact with each other, and form the ultimate black hole, with all the matter that once formed the universe. Then, it starts to give away its mass, as told by Stephen Hawking.

And it the end, it will explode with a bang (probably, as that is assumed). Could this be equal to a big bang?

No....the black hole wouldn't be expected to "explode" until it got very small and had very little mass. Up to that point the BH would have just been slowly shedding its mass very x10googolplex time

Add to that the problems with cosmic inflation and I'd say that we are pretty safe in saying this isn't the same thing as the big bang.

WayneFrancis
2009-Dec-03, 03:42 AM
Why does the Universe have to be "empty" to be considered a "black hole"? The speed-of-light constant (I think) reinforces the idea that we're INSIDE an event horizon...It's almost "intuitive"...!? It is, after all, the "Speed Of Lght" that keeps uss away from the boundaries of the Cosmos, and here we are (monkeys) wondering if we can go faster than the speed of light...when it's PHYSICALLY impossible!

The only real thing that Einstein said about intergalactic travel, was that it can be done easily, as long as it's a one-way trip... For the astronaut, it could be just a few months to Andromeda Galaxy...but he or she could never return, except to an Earth a few million years older.

I VOLUNTEER!!!

This not only is a ATM claim but one that has been debunked many times before.

WayneFrancis
2009-Dec-03, 03:43 AM
Ack I got caught by the necro post!!!