Time and the expansion of the Universe

Originally posted by kerrymac
I have a weird theory..that the universe is already expanding at the speed of light because it's fabric is space time...so because of the idea that travelling faster than light will send you back in time...quote]

Hey there kerry

I like the way you think.... Actually I have been pondering that the expansion of the universe is infact what we perceive to be time.

So what would happen if the universe stopped expanding??? I visualise it somthing like a timelapse camera. you know where you see every movement in trail. Like waving your hand around and seeing it in all the points it traveled through.

So it would follow that if the universe did stop for any given amount of time then time would also stop and we would have no perception of this.

there is a book called "permutation city" In this book there is a computer that creates a kind of Virtual world in the matrix style. Scientists then experiment with computation, only running calculations in ever increasingly long time slices. e.g only calculating one kb per hour. The effect was not felt at all within the virtual world, it carried on as normal with no effect at all. But on the outside looking into the virtual world everything apeared to stand still and change very slowly.

anyway... It's nice to see so many other thinkers out there... I was beggining to think I was alone in my train of thought.

BE Good

Tim.

Originally posted by slank
1. What if space is not expanding but matter is uniformly shrinking? The Universe is not getting bigger but we are getting smaller? (Just a thought)
2. What if the 'expansion' of the Universe is time? Sort of if you could contract the Universe you could run time backwards. Like reading a CD backwards instead of forwards. Sort of like it is gear driven. You could run the Universe forwards and backwards to re-play a favorite part.


.

Hey Slank,

1. That is a very intelligent thing to say... actually according to relitivity you are in fact right. We are all shrinking - that is relitive to the percpective of the universe so if you were traveling at the exact speed of the universe's expansion then you would see all matter shrinking....

A bit like what happens in a black hole........ spookey..... (Kidding E_T) hehehe

2. See my last post for the lowdown on my idea's on this

Cheers,

Tim.

[edit on 11-9-2004 by tim_uk74]

Would that suggest that there is maybe another Universe that is contracting while ours it expanding? The balance needs to be maintained?

You've heard some of the tachyon theories of particles that go faster than light and backwards in time?

I just thought, maybe the Universe is breathing!
"Inhale the good air, Out with the bad, . . ."
.

Originally posted by NetStorm
Here's an ignorant question regarding the expansion of the universe...does Newtons Third Law not apply? "For every action, there is an equal and opposite reaction"
If it does how would this affect the Universe?

If yours is an ignorant question, what would you call osme of mines? If you ask me that is a great question.

I think matter and anti-matter would be an example of your question. I don't know on the topic to elaborate. I remember from a Star Trek episode the concept of Time and anti-time, I don't konw if that is a real thing or just a story. Can anyone clarify on the possible existence of anti-time?

Or maybe Newton's laws apply only on heavenly bodies.

Originally posted by NetStorm
Here's an ignorant question regarding the expansion of the universe...does Newtons Third Law not apply? "For every action, there is an equal and opposite reaction"
If it does how would this affect the Universe?

That's a great question!
I don't think space-time is exerting any force on the galaxies since it is just the medium. Even if it is, I would say gravity would be the "opposite reaction." However as you know the expansion is being accelerated by the mysterious dark energy which seems to fail any effects of gravity. I don't know if it made any sense.

Originally posted by slank
1. What if space is not expanding but matter is uniformly shrinking? The Universe is not getting bigger but we are getting smaller?

This would only work if the constants of nature change exactly with the right amount to make it seem like we're not shrinking. Otherwise quantum effects would be increasingly dominant, because we become smaller. Also we would see more of the nuclear forces, which only have a certain range. If we become smaller and the constants don't change, we percieve that range as becoming larger.

What about space, what is it really? is it length? in three dimensions? In a huge cube of space could it be that it has 'grain'. Going from corner B to it's opposite coner, B', takes just a bit more time than going from corner A to A'? Or would it mean our original cube was not quite square, or that space was skewed. I wonder if there may be flow of space. Perhaps it would not be 'grain' of the Universe but going with the current of the Universe or against it. Anyone think in string theory there may be length/dimension particles/strings? they would have to be some of the most hyperfluid particles around. What about time particles/strings?

Spacetime is defined in general relativity has a topological space called a manifold. This manifold has certain properties that make it suited for us to live in. Its shape can change and that change is described by the metric of the manifold. It is also smooth and stays smooth no matter how much you zoom. The grain/skew you talk about is the shape of spacetime and is described by the metric. It is the shape of spacetime that causes gravity.

New theories don't have this view. Loop quantum gravity doesn't accept the smoothness. It says spacetime comes in little blocks that form a spin foam or spin network. In string theory there are a lot more dimensions which are curled up.

Yeah I like the idea of string theory. It kind of gives a reason for the big bang...well one theory in relation to the string thing is that in the beginning there were say ten dimensions and then because the structure was unstable (I don't know why - just work with me on this one) six or seven of them broke off and curled up into a very small ball.

We're now surrounding that very small ball in much the same way a person, who was in fact a drinking straw would think they were a one dimensional object (just a line) but would actually have width and depth that they were unaware of. So maybe we're all ten dimensional objects here...but we just don't know about it.

If so - our true selves could be fairly omnipotent (as omnipotent as you can be when everyone else is as well - maybe we're all part of the same thing in that case) but our "lives" could be the entrapment in, and travelling along the four dimensional space time continuim while the parts of us in other dimensions read a magazine or something. Oh I do hope it's not Hello magazine though - I hope I'm not a ten dimensional social climber. That WOULD be a bugger!

[edit on 12-9-2004 by kerrymac]

tim_uk74

Yeah I know what you are getting at but actually all physical object ocupie space and the only reason the exapansion doesn't seem to effect the objects is that the rate within a smjall locolaised area is so small that no change seems to take place.

But if all of space expanded at the speed of light then all matter would be stretched appart.....

Hi tim_uk74,

Maybe I'm missing the point here, but I still stand by my original post. Regarding the expansion of the universe (space) and relativistic effects on the material within it, we�re talking apples and oranges. The speed of light limit applies only in an inertial frame. The rate at which �space itself� expands and the rate of relative motion of a mass/particles, or the transfer of information, within space locally are two different things and are not subject to the same limits.

For instance, the �distance� between 2 galaxies may increase at a rate greater than the speed of light due to the stretching of space itself. However, this has no effect on the material that makes up the galaxies within the space. And so, relativistic effects like time dilation, infinite energy, etc. are not observed.

There's a difference between expansion taking place at a rate greater than the speed of light and the relalative motion of a mass in an inertial frame or the transfer, or propagation, of information at a rate greater than the speed of light. Relative motion of a mass and the propagation of information through space locally at a rate faster than light speed is forbidden by fundamental physical laws, but the expansion of space, or the universe, at superluminal speeds is allowed; in other words, as long as you are not transmitting any information (like a light pulse), you can make things happen at rates of speed greater than that of light.

A link that explains this in pretty simplistic terms is curious.astro.cornell.edu...

Have fun !!

Oh yeah, here's another link that might be helpful in getting a picture of all this:

www.wonderquest.com...





[edit on 9/12/2004 by netbound]

Hiya Netbound,

Very interesting links Thanks for that

What I was thinking was what if the expansion of space time were to expand at a rate that would affect the space between the nucleus and electron? See what I�m saying? Matter would literally rip itself apart.

This could be the BIG RIP I�ve heard about?

All the best People,

Tim,

P.S.

The transmition of information faster than light is an intersting subject in it's won right, as of course we all should know that there is evidance to suggest that through quantum tunneling information can infact be transmited faster than light.

Originally posted by tim_uk74
What I was thinking was what if the expansion of space time were to expand at a rate that would affect the space between the nucleus and electron? See what I�m saying? Matter would literally rip itself apart.
This could be the BIG RIP I�ve heard about?

Yes, it is the Big Rip theory. That is one possible fate of the universe. It could happen because eventually even our nearby galaxies would be "moved" a lot farther apart. And as I stated earlier, as galaxies move farther and farther apart, their recession speeds increase relative to us.

So, we will end up in a cold death. Eventually the expansion would be great enough to weaken all the other forces including the gravity and nuclear, ripping matter apart, but that would be after all the galaxies have moved farther enough not to see each other.

""It rips apart clusters of galaxies. It rips apart stars. It rips apart planets and solar systems. And it eventually rips apart all matter."
from: Big Rip Theory

Ekpyrotic theory states an alternative fate of the universe. According to this theory, our universe is a brane moving in a fifth dimension. And when the galaxies move way farther into the space, it would reach the boundary of another brane and thus instead of cold death, it would rather have a violent death following a collision with parts of the other brane. Further, according to this theory, our universe formed due to the same process.

"...'Lest you get too optimistic, galaxies are destroyed in a far more violent way,' Steinhardt said of the brane scenario. 'They are vaporized at the next 'bang' -- the collision between branes'..." - quote

More about Ekpyrotic theory:
wwwphy.princeton.edu...
www.space.com...
www.futuretalk.org...

Either way, the fate of our universe is not going to be pleasant!

(I edited my last post on the first page to make it less confusing!)



[edit on 14-9-2004 by jp1111]

Hi tim_uk74,

Yeah, I think I understand what you�re saying now. And, as jp1111 stated, it could possibly rip the fabic of spacetime apart. At least that�s one theory.

And also, you�ve got a good point about quantum entaglement and non-local instantaneous action at a distance. It�s a strange phenonmenon and would kind of support the notion that we are part of a seamless whole.

However, even through quantum entanglement, I believe the current thinking is that information is not passed between entangled quantum systems. These quantum systems may influence each other instantaneously, but they are not truly passing useful �information� between each other. Here�s a link that may explain this better than I can:

www.campusprogram.com..." target="_blank" class="postlink" rel="nofollow"> www.campusprogram.com...

I don�t know that the above is considered final thinking on the matter, though. David Deutch may have other ideas on this, but, it would entail acceptance of the Many Worlds interpretation of Quantum Mechanics. Here�s another article regarding quantum entanglement and the passing of information between entangled quantum systems:

plato.stanford.edu...

Nice thread �



[edit on 9/15/2004 by netbound]

[edit on 9/15/2004 by netbound]

Jp1111,

Ekpyrotic theory is kind of neat. It derives from superstring theory, as I�m sure you are aware. Personally, I find it a much more appealing model than the Big Bang model (for what that�s worth www.abovetopsecret.com..." target='_blank' class='tabOff'/>) because it doesn�t involve a singularity. As a scenario it just makes more sense to me, and is much easier to swallow.

I believe Ekpyrotic theory derives from M-Theory, to be specific than just saying superstring theory. M-Theory is the 11-dimensional model that unifies the 5 distinct string theories, and is the best bet right now for a possible Grand Unified Theory. It uses membranes (branes) as the fundamental object. Ekpyrotic theory conjectures that our universe may have begun as the result of the collision of 2 of these branes, and where the 2 branes �stuck� kinetic energy gave rise to elctrons, protons, quarks, etc..

Great post � www.abovetopsecret.com..." target='_blank' class='tabOff'/>

Originally posted by netbound
Jp1111,
Ekpyrotic theory is kind of neat. It derives from superstring theory, as I�m sure you are aware. Personally, I find it a much more appealing model than the Big Bang model (for what that�s worth www.abovetopsecret.com..." target='_blank' class='tabOff'/>) because it doesn�t involve a singularity. As a scenario it just makes more sense to me, and is much easier to swallow.

Superstring theory and the following M-theory are very interesting. Many theories trying to model our universe are based on the superstring theory, which is further based on the quantum field theory.

And, yes ekpyrotic theory does actually explain what caused the "bang," while big-bang theory does not. There are many other problems with big-bang theory like horizon, flatness, etc.. Although, theories like the ekpyrotic are quite based on assumptions, they are not falsifiable due to our limited technology and that is why they are so interesting.

Originally posted by jp1111

Originally posted by netbound
Jp1111,
Ekpyrotic theory is kind of neat. It derives from superstring theory, as I�m sure you are aware. Personally, I find it a much more appealing model than the Big Bang model (for what that�s worth www.abovetopsecret.com..." target='_blank' class='tabOff'/>) because it doesn�t involve a singularity. As a scenario it just makes more sense to me, and is much easier to swallow.

Superstring theory and the following M-theory are very interesting. Many theories trying to model our universe are based on the superstring theory, which is further based on the quantum field theory.

And, yes ekpyrotic theory does actually explain what caused the "bang," while big-bang theory does not. There are many other problems with big-bang theory like horizon, flatness, etc.. Although, theories like the ekpyrotic are quite based on assumptions, they are not falsifiable due to our limited technology and that is why they are so interesting.

Hi all,

What I don't understand about M-theory is that the universe is supposed to be created with the collision of super stretched branes - where as the enegery for the creation of the universe comes from the over stretched nature of the brane......

My question then is where does our universe reside? actually on or in one of these branes? is normal matter streaming around a brane like beads of water floating around the edge of a soap bubble?

Unlike some I find M-theory harder to comprehend because it just raises more and more questions.

though I have to say that the Big Bang theory only answers one part why and how... I think if we could understand Singularities in more depth we could discount it as being a cause of everything, Of course according to sTring Theory there isn't anything called a singularity....

Also I was reading very resently that We physists may have got it all wrong on a quantum level to start with so would make unifying very difficult.

I have read into the fact that Light might not actually contain Photons, and in fact Photons may not exisit at all.

Everything could then be explained as just being frequency waves which of course would support String Theory.

Anyway, I have work to do People,

All the best,

Tim.