# Universal-Expansion Hypothesis Query

1. Sep 16, 2012

### drshi

Hi,

I'm a writer, not a physicist, so this is a hypothetical question. In a work of science fiction, would it be conceivable to explain the ultimate outcome of universal expansion this way? "As its withdrawal speed increases exponentially and approaches infinite velocity, it collapses into a black-hole singularity with such force that it emerges from the other side as a big bang." Please be gentle with your derision.

Thanks,
Rob

2. Sep 16, 2012

### Chronos

Try the sci fi forum.

3. Sep 16, 2012

### drshi

Hi,

In a work of science fiction, would it be conceivable to explain the ultimate outcome of universal expansion this way? As the withdrawal speed increases exponentially and approaches infinite velocity, it collapses into a black-hole singularity with such force that it emerges from the other side as a big bang in a new dimansion. Please be gentle with your derision.

Thanks,
Rob

4. Sep 16, 2012

### phinds

Black holes form due to things coming TOGETHER, which is the opposite of your scenario, so most emphatically, NO. What you have is just babble, but don't worry, scific is full of babble. Just make the story good.

5. Sep 16, 2012

### drshi

You sound certain about what happens when something reaches infinite velocity.

6. Sep 16, 2012

### Staff: Mentor

Infinity isn't a number, so nothing can "reach" it. If we were able to look infinitely far out into the universe, we would see galaxy velocities increasing without bound. No matter how far we looked we would be able to measure velocity and assign a number to it. At no point will something reach "infinite velocity".

7. Sep 16, 2012

### Staff: Mentor

As I posted in your other thread, infinity isn't a number in the sense that you could ever "reach" it or even approach it. The recession velocity of galaxies simply increases without bound. As for your question, no, it wouldn't work because nothing is actually moving through space at any velocity. In the frame of every receding object, they are not moving at all and it is the rest of the universe that is expanding away from it. Recession velocity also increases linearly, at around 74 km/s per megaparsec in distance, not exponentially. IE objects at 1 megaparsec recede from us at about 74 km/s, while objects at 2 megaparsecs recede at a velocity of 148 km/s, at 3 megaparsecs it's 222 km/s. This of course ignores the acceleration of the rate of expansion.

8. Sep 16, 2012

### phinds

This is a terrific forum for discussing mainstream physics, but you are skating on thin ice.

If you are going to contend that a physical object can reach infinite acceleration, or even velocity, you are making a statement that goes WAY out side mainstream physics (to the point of being ridiculous, actually).

The rules here are that such statements require citations. Since this particular statement cannot possibly be supported with citations, you are breaking the forum rules.

9. Sep 16, 2012

### someGorilla

I find the idea of collapsing by expanding very fascinating! Something Italo Calvino might have written a wonderful story about.

I don't get your point. He's talking about an accelerating expansion going all the way to zero density in finite (proper) time. Or so I interpreted it. A sort of inversive big bang. You could have exactly the same objections about the big bang, right?

10. Sep 16, 2012

### someGorilla

To "merge" anything with anything else the way you hope to do you'd need to know it pretty well. You certainly wouldn't be the first to find deep connections between physics and your philosophical outlook on life. But if you think you already know it all you're not going to get very far. I get the slight impression that you care more about bending things to your ready-made ideas without understanding them in depth than to form your ideas from your understanding of the world. Maybe I'm wrong.

11. Sep 16, 2012

### Staff: Mentor

PF is a forum for SCIENCE. Not for spiritual ideas. Infinity is a specific concept in math and science, and if you want to use another definition or concept for it then you should go elsewhere, as we can only discuss science here. The same applies to discussions of reality.

Ah, you are correct, I misread the beginning of the post, my mistake. So yes, we would have to include the accelerating expansion obviously.

Drshi, I am with SomeGorilla in that it appears you may just want some way to had wave physics into explaining the fate of the universe in your own personal way. I stand by my statement on infinity, and I can't see how an expansion causes a collapse into a singularity followed by a big bang. Expanding into a collapse with enough force to cause a big bang doesn't even make sense. Heck, it isn't that it doesn't make sense, it's that is against known laws of nature. Now you can choose to explain it this way if you'd like, but this is completely against standard cosmology and physics.

12. Sep 19, 2012

### r4z0r84

Worked out that if the universe expands at the speed of light in all directions and if we are in the middle of the universe(unlikely) you would need to travel 14.6Billion light years away in an instant(if our universe is 14.6 billion years old source Google)

The only physical way to gain infinite acceleration beyond the known speed of that which is light is infinite energy, if it were possible to create infinite energy worth noting that even suns die, this power source would need to get stronger as time goes on, not to mention what ever it is your traveling in would need to also be infinite in strength to withstand the heat and all the stars/planets ect. that you would have to blast through on your journey.

This would also mean what ever ship would need to be able to create a path big enough for the ship to pass through without any friction. using more power to be able to destory literelly anything in its path.

I know this is more focused around getting to another dimension via a black hole, as stated in the previous post black holes are the opposite of what your talking about, i guess you could make up a white hole? that instead of sucking everything into it, it blows everything out effectively a big bang.

I could just imagine this now, a ship carrying the last survivors of earth decided to go back in time via destroying everything in their path to get past the edge of time itself in a speed faster than light, all of this just to continue the life of humans, coming back to earth at an earlier time before the earth was inhabitable, possibly creating a paradox of sorts leaving it open ended to continue another book.

This may all be just random stuff but yeah, my thoughts on the matter. i do understand that everything above is extreme speculation and hence i beleive i can do so in the scifi area, as it basically throws physics out the window.

13. Sep 19, 2012

### Staff: Mentor

The velocity of receding galaxies increases with distance. The majority of galaxies we can see currently are already receding away from us faster than c.

Not only is it not possible to have infinite energy, you couldn't apply an infinite force to get the infinite acceleration. And this still wouldn't get you past c. You cannot reach the speed of light or exceed it.

Doesn't matter. At extremely high speeds that are very near c the background radiation is blue shifted so far that you would literally annihilate yourself from all the gamma radiation.

This makes zero sense in regards to actual physics. This may be the Science Fiction Writing forum, but anything brought up still needs to be realistically possible or it doesn't belong here on PF.

It isn't speculation if it's just plain wrong. And good sci-fi does NOT have to throw physics out the window. It can be just the opposite.

14. Sep 20, 2012

### r4z0r84

I agree with everything stated above, This is impossible by our current understanding of physics.

There is a difference between Imagination and Knowledge.

Family Guy
So in imagination land,

In real life, No.

To pick apart the ops question, velocity/speed is relative infinite is not a defined speed as it has no bounds hence it would be impossible to "reach" or "approach"

In answer to the question at hand i offered a poppycock explination of what would be required to go to the other side of the "big bang" in turn showing that it is impossible.

15. Sep 22, 2012