What is it like on the outer edge of the universe?

[imported_jb]

never read on string theory.
i don't think i can buy that 3-torus. it would be nice if it was true tho.
i dunno, i can't beleive that the universe took that curled shape. when did it's ends meet? immediately after the big bang? you'd have to beleive that what ever the big bang happened in (what is outside the universe) is powerful enough to mess up X, Y and Z whenever they exist. ya know?
freakin' mind blowing if its true.
if it is, maybe some day we will have things that sense occurences faster than the speed of light, allowing us to see past events as they happen. or even spy on china in realtime. eyes in the back of your head. theoretically tho... i doubt that there is too many good line-of-sight's between now and the next past-earth.

 

[Neptune3000]

http://www.pbs.org/wgbh/nova/elegant/program.html


there you go. One of the most fascinating programs i"ve ever seen. You can watch it all online by the way. Let me know what you think.

 

[imported_jb]

well.
based on that program alone, i don't like membranes. they barely scratched the surface on a few key topics. i'll beleive that electrons and photons and stuff are open strings. for some reason, i want to say that a magnet wouldn't have north and south if all strings were closed. i don't need the ends of the string to be connected to a membrane or something tho. i think they're fine being absolutely shaped like an open string.
the idea of membranes that they presented almost seemed like they were just visualizing the presence of the rest of the universe in relation to the string. ya know what i mean? that the "plane of existance" in the equation is the string next to this one and the rest of the particles that make up the rest of the atom... that make up our universe. maybe there is more to that tho. maybe they said some strings could have/be membranes, not all of them. whatever.....

 

[Neptune3000]

Seeing as it's ment to "joe friendly" ofcourse they did'nt delve far into the membranes. Just like how general relativity has made certain predictions(blackholes, wormholes) and quantum mechanics has made certain preditictions(parallel universes) is the samething that membranes are a prediction.

they did not say why membranes are predicted by string theory([prolly not to be too confusing) they're just saying that our universe is a membrane floating in a higher dimension.

in addition, if you take a look at general relatibity(how it explains gravity) while quantum mechanics explains all the other forces you can see that all these things really is make them "meaningful" to us. The universe could just be a melting block of ice for all we know, but scientists have'nt found a way to garner that "meaningfulness" from what we experience.

For instance, scientits cannot explain gravity in terms of a particle yet and why gravity is'nt as strong as electro magnetism, string theory does all that.

I personally love string theory. The whole idea behind these theories is to explain things and find connections between them to what we see and know. seeing as general relativity and quatum mechanics are the 2 pillars of modern physics string theory has a good head start.

 

[Smilin]

This is wordy, but I'm trying my best to keep it brief. Please stick with me.

If you stick with the traditional "It just goes on forever" view you have this: The edge of the universe is where you go from "something" to "not something". Right now the edge is the emitted light that's traveling outward from the furthest most object. To see what is beyond you would have to catch up to the furthest most object, then catch up and pass the light that was emitted from it. You would need to go faster than the speed of light and travel in time. By moving in time / faster than light you would need to essentially move in the fourth axis of a three dimensional universe.

Now assume for the moment that the universe is spherical (as depicted in on example in that earlier link). That is, assume if our three dimensional universe were represented as a surface of a sphere (reducing everything by one dimension to make it comprehensible.) The third dimension would represent time. In this way you can have a universe that never ends without being infinite in our true three dimensions. If it were expanding or collapsing to see what is outside the edge you would still need to move in the added axis, time. You would need to outrun the expansion or contraction to see.

Now here is a bit that conflicts with the usual Hubble oriented view of the universe. If the universe were collapsing into a singularity or "falling into a black hole" at some "infinite" distance away then it could be perceived to be expanding at an accelerating rate (per Hubbles assumptions). Object closer to the singularity would be accelerating faster and therefore red shifted. Object further away would be accelerating into the singularity but not as fast as we are. They would also be red shifted. The only blue shifted objects would be those perpendicular to the axis of collapse. If the singularity is at an infinite distance then the slice of the universe containing blue shifted objects would be infinitely thin (none!).

Now take this view of a collapsing universe and go find the edge. The first thing you'll notice when you do is that since you are an "infinite" distance from your starting point the universe as you originally observed it will be infinitely small and already in a singularity. The next thing you'll notice is that you had to travel faster than the speed of light to get to where you are. To leave the edge of the universe you will need to continue traveling faster than the speed of light. This is exactly what is required to leave a singularity or black hole.

What does the universe look like? What shape is it? Simple it has none. We are already in a singularity and the edge of the universe is an event horizon. We can no more tell what is on the outside of it than we can tell what is on the inside of a singularity. What we view at the edge of the universe from our present location is simply what has fallen into our singularity. If we leave the universe we will look back at it and see merely a point. That is it's shape.

If we travel further from whereever it is we are at when we leave we can find eventually if we move far enough it becomes a point as well. It is not necessary to have something for the universe to expand into. If our three dimensional universe is a piece of cardboard we do not need "not cardboard" for it to expand into. We simply wrap it into a sphere so the cardboard can expand without "not cardboard". Then travel in the dimension that the cardboard is expanding or contracting. In our three dimensional universe this means traveling faster than light or moving in time.

 

[fested]

thanks for that well thought out post, Smilin. great food for thought, even if a good cup of hot tea had nothing to do with it.

 

[wjgollatz]

Originally posted by: Mik3y
hmm...well, isnt it theoretical that the universe would shrink back down once it stops expanding? in that case, would anything be able to exist outside of the universe?

i dont totally understand about all this cool junk. i'm only 18.

That is theory that belongs int he superstring theory - perhaps not officially, but string theory suggests that. The big bang was caused by to branes colliding into each other - and like a rubberband, bouncing away from each other (remember the major problem with the big bang theory - is - where was the origination of the expansion - it is still not evident). Eventually - the expansion of the universe we exist in will slow (still in accelerating expansion right now), stops, and collapses again - if the brane straightens back out again and hits the brain we blew away from - or another one - then - game over - the big bang happens again. But don't worry - our sun will burn out before then.

 

[Smilin]

Originally posted by: fested
thanks for that well thought out post, Smilin. great food for thought, even if a good cup of hot tea had nothing to do with it.

Yeah, sorry. But hey all I have is this vending machine that dispenses something that tastes almost, but not quite, entirely unlike tea.

 

[imported_jb]

http://www.superstringtheory.com/ suggests that the universe is open, and infinite in size. if it was tho, i doubt that a heat source infinitely away could still keep our space warm to any degree. i guess it could tho. (assuming we are infinitely large, but in a closed loop like stated above.) the heat doesn't exactly have anywhere to radiate to.

 

[DrPizza]

Originally posted by: fested
thanks for that well thought out post, Smilin. great food for thought, even if a good cup of hot tea had nothing to do with it.

Yeah, I liked that post too... but, if you exited the universe and looked back on it, how could it look like anything? The photons of light haven't gotten to you, so you would see nothing, not a point.

 

[DrPizza]

Here's something I thought of years ago, which isn't too on this topic, but close enough...

What if big bangs were common, and could occur within our universe? And, what if some other universe was expanding in our universe at nearly the speed of light? And... what if the outer edges of that universe were just reaching pluto right now...

 

[eigen]

This link may be to hardcore for most.But If want to read some cool shiit about the topology of space check it out.Even if you think math is the devil it has cool pics. http://www.ams.org/notices/200406/200406-toc.html

click on the link and then click on the link that says poincare docadecehedral space....

basically says the universe is crystalline is shape...

 

[Smilin]

Originally posted by: DrPizza

Originally posted by: fested
thanks for that well thought out post, Smilin. great food for thought, even if a good cup of hot tea had nothing to do with it.

Yeah, I liked that post too... but, if you exited the universe and looked back on it, how could it look like anything? The photons of light haven't gotten to you, so you would see nothing, not a point.

You're going to run into that paradox long before you leave the universe. Remember you'll have to time travel/go faster than light to reach the edge. You get the classic "what do you see if you turn on a flashlight while sitting on a train moving the speed of light?"

The only way to think around it is to use the word "Perceive" instead of "see". Since it can't really be done that we know of it can only be thought about abstractly and you'll run into those sort of paradoxes.


The glass plate on one side of the "fish tank" that we all exist in is the speed of light which represents just how large things can be. The other glass plate is how small things can be and is represented by the plank constant. As hard as we try we're always going to bump into the edges of the fish tank.

Perhaps someday someone will have a complete stroke of genius and figure out what we've been missing. He'll simply jump out of the fish tank! As exciting as that may sound, I don't want to be the first to have such a thought. Chances are once he leaves our universe he'll end up flopping on the carpet outside the tank, unable to breath.





Edit: I Percieve E except after C.

 

[Smilin]

I dig this thread - one bump to stop it from disappearing.

 

[imported_jb]

if you assume we are in a sphere, expanding outwards, you could argue that the edge just gets tougher to move through in our dimensions of space in time. that you would just end up going slower and slower and the edge would always be an 'infinite' distance away.

ok. so assume the universe is a closed loop like the 3-torus and other models, where going in one direction will bring you back to the same point, no matter how large the universe actually is.
now "the outer edge of the universe" is actually referring to what is 'outside the donut'. we can never get there conventionally. if we sent our indestructable camera, at super-lightspeed, off the edge of the universe to get a look, it would just end up hitting us in the back of the head.

i see no way to get there. assuming blackholes are just points in our universe and not 'pinned to the edge.'

one thing that kinda worried me was the gravitron experiments going on in europe or something, mentioned by that nova series. they were hoping to make one appear and watch it disappear or something by using a particle accelerator maybe.

play with those things enough, and they'll probably blink us out of existance!

 

[sao123]

The end of the universe seems to be a paradox in itself.

1) The universe is a closed system.

2) The universe encompasses the entirity of the 3 dimentional entity (all matter, all matter filled space, & all void space (3 dimentional null space) ).

3) Therefore nothing 3 dimentional can exist outside of the universe.

4)Yet, we claim that the universe is closed and expanding, which further requires that outside of the universe must exist 3 dimentional void space for the universe to expand into. Thus violating #1 or #3.

 

[BriGy86]

has anyone ever watched a show on space and how the scientists explain that when they look at some of the far off distant things they're looking at it, as it was a million years ago because it took so long for the light to reach here? in a sense we are looking back in time.

just wondering if any one has seen that.

 

[wjgollatz]

Cosmic radiation background experiments are giving results that the universe is flat (the CMB is pretty much uniform, indicating few patches of the CMB - CMB coming from the big bang - uniformity meant that expansion was uniform as a whole and that gravity did not effect space-time) - not closed like a sphere (that is in a flat universe, the volume on average is not curved from - curving of space-time from the mass of gravity - local space-time curvature around objects can exist - in fact - it was reported a few days ago that a satellite testing this - found space-time around earth to be curved - as expected)

Regarding shapes of the universe and string theory; string theory suggests that at the big bang - of the 10-11 dimensions, 3 inflated rapidly during the inflation parts of the big bang, because their confining strings broke loose from the heat - the heat causing them to destroy each other when colliding with other strings, probability theory is combined with that to state that as the 3 spatial duimensions un wrapped, the probability of the other 6-7 dimesions breaking free of their strings were reduced because of their shapes. The other weird shapes/dimension exist microscopically in the three spatial dimensions (or 4 if you count time). But then, parts of string theory suggest that out universe is contained on a "membrane" - and the shape of that membrane is speculative (hell string theory is still speculative).

 

[wjgollatz]

Originally posted by: jb
so what did that Topology link say? that the CMB data is uniform, right? they said that they'd expect to see reflections from "the other side of the universe", but i see a couple of problems with that. 1) the possibility that the bounds didn't come back yet. 2) they could have been thru enough already so that it appears uniform. (perhaps waves are faintly there or dissolved) 3) what i thought the 1st time i heard about CMB, there is just already enough noise from objects occuring once in the universe for the CMB to appear uniform.
yup.

I believe the CMB also designates temperature - and that can be back-calculated with the other theories to suggest that the CMB readings are correct to say that they are from the BB. Its only like 400 photons or electrons per square foot on measuring tool I believe. And within the CMB - the polarity can be measured and all sort of other stuff.

 

[bugsysiegel]

Originally posted by: TuxDave
So if you move towards the edge, you'll basically shrink since space-time is so compressed. So let's say the edge of the universe is 2 meters away. If you walk 1 meter forward, you'll shrink 2x So if you walk another 1 meter forward (in your perspective), you're only moving 0.5meters and you shrink another 2x. You'll never get to the edge. Inside the universe, the edge seems infinitely far but in fact it's very close but you just can't get there.

If this is the case, couldn't the "edge" of the universe actually be just beyond the solar system? The above logic would support a relatively "near" edge, since, as stated, the closer we get to it, the smaller we are, the further away it would appear to be.

For this to be the case, I would have to explain the stars, which appear to be a significant distance away. My thoughts on that, based again on the above theory, is that the stars are reflections of the past, cast upon the fabric of whatever surrounds our solar system.

 

[Mayax]

From another thread, same answer...

Space is expanding in three dimensions right? Not entirely, time is expanding also. This brings the answer a hell of a lot closer to home.

You're sitting at your desk right now, this very instant. Right now, you have a space-time coordinate that exists and as each second passes away the universe can account for that space-time coordinate. Now, think about yourself next wednesday at exactly 3 pm and what you might be doing. As far as the universe is concerned, that space-time coordinate doesn't exist. We all know it eventually will though.

Now, what exactly is it that's between this second and 3 pm next wednesday? Don't just think about the time, you have to account for yourself and the entire universe along the way.

If you can answer that, that's what our universe is expanding into. No, it's not expanding into time. That would imply that time and the universe exists in the future beyond our conscious recognition of it. Time, along with the universe is expanding into something else. What is it? It's whatever it is that allows you and the universe to come into being next wednesday. As far as we and the universe are concerned, it's "nothing" until we get there and stamp our dimensional existence on it.


And no, 3pm next wednesday holds no cosmic significance. It was picked out of thin air.


So, here's some homework...

What if we're on a collision course with another expanding universe in that "nothing" between now and next wednesday?