The universe can't expand beyond our reach

[Baby Astronaut]

It's said that the universe is expanding at such an increasing rate that its outermost areas will pass a cosmological "event horizon" that is beyond our reach. Afterwards, evidence of that part of the universe will vanish forever.

 

Not true.

 

I may have no evidence to present, but all you really need to do is extrapolate on a basic theory to know it might become possible to see any part of the universe beyond that supposed event horizon.

 

Wormholes are the key -- if they exist. If they don't, other ways are sure to pop up.

 

Such means of travel don't care if a spot in universe is not reachable by conventional means. Unless, of course, I'm wrong. Thus my reason for posting: your counter-remarks or agreements.

[iNow]

I may have no evidence to present...

 

This about sums up the problems with your post.

[Martin]

...

 

Wormholes are the key -- if they exist. If they don't, other ways are sure to pop up.

...

 

Reminds me of a great quote from Groucho Marx"

 

"Those are my principles, and if you don't like them, well...I have others."

 

http://www.quotationspage.com/quote/499.html

[iNow]

From a link shared by Martin a while back:

 

http://www.scribd.com/doc/3366486/SelfOrganizing-Quantum-Universe-SCIAM-June-08

"Although such phenomena have never been observed, physicists have speculated that wormholes might fnd a justifcation within the still unknown theory of quantum gravity. In view of the negative results from the computer simulations of Euclidean quantum gravity, the viability of wormholes now seems exceedingly unlikely. Wormholes come in such a huge variety that they tend to dominate the superposition and destabilize it, and so the quantum universe never gets to grow beyond a small but highly interconnected neighborhood."

[Martin]

From a link shared by Martin a while back:

http://www.scribd.com/doc/3366486/SelfOrganizing-Quantum-Universe-SCIAM-June-08

 

Sorry to say that link no longer works but here's an alternative that gets the same text ( just without the graphics illustrating stuff in the article.)

http://www.sciam.com/article.cfm?id=the-self-organizing-quantum-universe

This version doesn't have the graphics embedded in the text but instead has a secondary link with some animated graphics that go with the article

http://www.sciam.com/slideshow.cfm?id=the-self-organizing-quantum-universe&thumbs=horizontal&photo_id=83B49077-FBA4-DF34-5C7B69BCA7932B25

 

I think it's a great article and highly informative about that particular team's research (simulating quantum universes in computer and studying them.) But I actually don't agree with every statement they make in generality. They found for their type of model, allowing wormholes caused it to break down. But I'm not confident about how that applies to several other quantum gravity approaches.

So based on that one team's findings I'm reluctant to draw conclusions. Have to think about it. I'll post some more later after supper.

===================

EDIT: I have to leave it non-committal. Essentially BabyAstro is saying that traveling faster than light (by taking a shortcut or other unspecified means) is possible. Personally I judge the possibility so remote as to be uninteresting to think about. It also leads to logical difficulties, I don't even want to go there. But I don't know offhand how to logically rule hyperfast travel out. Maybe someone else does.

Edited October 29, 2008 by Martin

[Baby Astronaut]

Well, I've based my assumptions off posts in this thread.

 

And no one disputed posts #8, 9, 11, and 13, which are full of talk about wormholes.

 

It's said that the universe is expanding at such an increasing rate that its outermost areas will pass a cosmological "event horizon" that is beyond our reach. Afterwards, evidence of that part of the universe will vanish forever.

 

Not true.

It's more correct to say "it's likely we'll never reach beyond that horizon, unless we discover a way unknown to scientists yet".

 

I may have no evidence to present, but all you really need to do is extrapolate on a basic theory to know it might become possible to see any part of the universe beyond that supposed event horizon.

No evidence is needed to support a "might" scenario, if it's clearly written as such, although this thread's title doesn't say "might", I admit.

 

Wormholes are the key -- if they exist. If they don't, other ways are sure to pop up.

 

Such means of travel don't care if a spot in universe is not reachable by conventional means. Unless, of course, I'm wrong.

Perhaps I should restate: other ways might pop up. But I did use "if" and "unless I'm wrong".

 

I just believe it goes both ways: saying "it'll never be possible" requires as much proof as saying "it will occur".

Edited October 29, 2008 by Baby Astronaut

[Martin]

...

 

I just believe it goes both ways: saying "it'll never be possible" requires as much proof as saying "it will occur".

 

I agree, it goes both ways.

I'd tend to hold back from making a flat declaration either way.

 

What I said about that horizon business in the Aterna's Question thread was if you take any galaxy with redshift 1.7 or more (of which we can see plenty) and if you left Earth today going towards it, traveling at the speed of light, then you 'd never get there.

 

Or if today you sent them a flash of light signal, the signal would never reach them.

 

(that statement does not involve the question of traveling faster than light, it doesn't go outside the bounds of ordinary astrophysics)

 

BTW the distance to that horizon changes over time, depending on how much expansion is accelerating---it has been farther away in the past.

[Baby Astronaut]

BTW the distance to that horizon changes over time, depending on how much expansion is accelerating---it has been farther away in the past.

Interesting. I guess the final distance to it will be immediately outside the lone super cluster that we'll belong to in 100 billion years, as predicted.

[iNow]

.

Sorry to say that link no longer works but here's an alternative that gets the same text ( just without the graphics illustrating stuff in the article.)

http://www.sciam.com/article.cfm?id=the-self-organizing-quantum-universe

 

This version doesn't have the graphics embedded in the text but instead has a secondary link with some animated graphics that go with the article

http://www.sciam.com/slideshow.cfm?id=the-self-organizing-quantum-universe&thumbs=horizontal&photo_id=83B49077-FBA4-DF34-5C7B69BCA7932B25

Right on, thanks man. I didn't even check the link. I read the article from that link months back when it still worked, and hadn't realized there was a change.

 

 

But I actually don't agree with every statement they make in generality. They found for their type of model, allowing wormholes caused it to break down. But I'm not confident about how that applies to several other quantum gravity approaches.

A worthy clarification, indeed.

[Baby Astronaut]

Sorry to say that link no longer works...

Here's a newer document with the original info.

[Martin]

Here's a newer document with the original info.

 

It's great to have that link! I couldn't find a complete online version with all the illustrations. The graphics definitely help understand.

 

Interesting. I guess the final distance to it will be immediately outside the lone super cluster that we'll belong to in 100 billion years, as predicted.

 

Interesting issue, what the distance to the cosmological event horizon is tending towards. You might be interested in Figure 1 on page 6 of this article. It shows how the event horizon has evolved and will evolve through time. And also how the Hubble radius has gradually extened out as the Hubble parameter H(t) has gotten smaller. It shows stuff graphically, often more effective than either equations or words. If you look it up and have questions, ask. This is a Lineweaver article that did NOT get published by the SciAm---maybe it should have been, but some other publisher got it.

http://arxiv.org/abs/astro-ph/0305179