Edge of the Universe

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darkmatter4brains

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mental_avenger":184kdvy3 said:
As much as we would like to believe in the possibility of time travel or different rates of time, I think that time itself may be one of the few unalterable absolutes in the Universe, sort of a background which is behind everything else that takes place.
The folks running the GPS constellation are going to be disappointed to here this!! The fact that time runs at a slower rate in orbit compared to on Earth, needs to be constantly corrected for in order for the GPS systems we use every day to not accumulate errors measured in km's!
 
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SpeedFreek

Guest
Yup. And absolute time/space is precluded by the constancy of c.

Einstein worked out that, if the speed of light in a vacuum is constant to any inertial observer, then space and time must be dynamic. He published his theory around a century ago and it solved the problem that Newtonian physics could not account for - the precession of the perihelion of the orbit of Mercury. The theory has since succeeded in other areas, and is today used unknowingly by millions of people across the globe in their GPS systems.

It doesn't matter if mental_avenger thinks that there is some form of absolute time separate from all the ways we use to measure it. The contents of this universe, including the planet Mercury, adhere to the same notions of time and space as Einstein.
 
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dangineer

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Perhaps it may be beneficial to consider relativistic effects as just illsionary effects, at least from a conceptual sandpoint. However, there are some effects which we will, and do, have to deal with in our own reference frame, even if they are just illusionary. For these effects it may be more practical to consider them as real effects. For instance, one of the technical challenges in building an interstellar spacecraft is the relativistic mass problem. From the standpoint of the spacecraft, it does take more energy to accelerate the ship to anywhere near the speed of light. Even if this effect is some kind of illusion, we still need to deal with it as if it were real.

This is the big problem with particle accelerators, they require more and more energy to accelerate the particles closer and closer to the speed of light.

MA, I can see basically where you are coming from, but I'm still a little confused about the superluminal recession problem. Could you please expalin it again and show us how relativistic mass factors into it?
 
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alfa_georgios

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Re: if we caught up with the end of the universe ????

JeffreyNYA":1bo429kn said:
I am not sure I buy the whole universe is expanding thing. Not sure how we would even know. If we can't see to the edge of it then how do we even know there is an edge. I don't think there is. There is universe everywhere. We see Galaxys moving away from each other and thats fine, not hard to accept that.

I think the Big bang happened eveywhere at one time. It was just not some little point that you could say, oh look, here is where it first happened.
i totally agree with you Jeffrey! Complies perfectly to God's infinity.
 
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Booban

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...same thing that was before the Big Bang

Cpickens89":1uoyg2z7 said:
so if the universe is expanding outword what exactly is it expanding out in ??

and if we managed to catch up with the edge of it if we went passed it what would there be ?

would we pop into another universe or what ?
My explanation is very simple and has the bonus of answering another question, "What was there before the universe existed, ie. the Big Bang?"

The answer to both these questions is, how unsatisfying it may be, is NOTHING.

The universe is stuff, you, me, planets, stars, photons, dark matter whatever it is, it is something.

Space is the void, nothingness, Never Ending Story kind of nothing.

Nothing is very hard to grasp because you would then have to think of nothing...which is impossible because as soon as you try to think of nothing you think of a giant marsh mellow man.

But that is what Space is....NOTHING. Therefore, before the universe, or beyond it, after you catch up to the very last bit of cosmic big bang wave, and even in-between a tool bag and an astronauts hand, is the antithesis of something...which is nothing.
 
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Mitchrobbo

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It's really strange to think about. But if no living thing can ever reach it.... does it exist?
 
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origin

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Mitchrobbo":1b9veio5 said:
It's really strange to think about. But if no living thing can ever reach it.... does it exist?
The simple answer, strangely enough, is that for us, no the edge does not exist. It is kinda like you can't get there from here.

In a sort of thought experiment lets assume that there is some entity that is somehow outside our universe and they were looking at our universe and seeing it as some sort of bubble if you will. It could be that this entity would notice that you just happen to be only 1 mm from the edge. The edge would still be completely undetectable to you or any device that exists in the universe so for all intents and purposes the edge does not exist.
 
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Mitchrobbo

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Booban":15ualt4l said:
Cpickens89":15ualt4l said:
so if the universe is expanding outword what exactly is it expanding out in ??

and if we managed to catch up with the edge of it if we went passed it what would there be ?

would we pop into another universe or what ?
My explanation is very simple and has the bonus of answering another question, "What was there before the universe existed, ie. the Big Bang?"

The answer to both these questions is, how unsatisfying it may be, is NOTHING.

The universe is stuff, you, me, planets, stars, photons, dark matter whatever it is, it is something.

Space is the void, nothingness, Never Ending Story kind of nothing.

Nothing is very hard to grasp because you would then have to think of nothing...which is impossible because as soon as you try to think of nothing you think of a giant marsh mellow man.

But that is what Space is....NOTHING. Therefore, before the universe, or beyond it, after you catch up to the very last bit of cosmic big bang wave, and even in-between a tool bag and an astronauts hand, is the antithesis of something...which is nothing.


So..... if it's nothing, just space. Are humans or any life form able to move through it?
what happens when you enter this 'space'
 
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darkmatter4brains

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Mitchrobbo":1yzqnr7g said:
Booban":1yzqnr7g said:
Cpickens89":1yzqnr7g said:
so if the universe is expanding outword what exactly is it expanding out in ??

and if we managed to catch up with the edge of it if we went passed it what would there be ?

would we pop into another universe or what ?
My explanation is very simple and has the bonus of answering another question, "What was there before the universe existed, ie. the Big Bang?"

The answer to both these questions is, how unsatisfying it may be, is NOTHING.

The universe is stuff, you, me, planets, stars, photons, dark matter whatever it is, it is something.

Space is the void, nothingness, Never Ending Story kind of nothing.

Nothing is very hard to grasp because you would then have to think of nothing...which is impossible because as soon as you try to think of nothing you think of a giant marsh mellow man.

But that is what Space is....NOTHING. Therefore, before the universe, or beyond it, after you catch up to the very last bit of cosmic big bang wave, and even in-between a tool bag and an astronauts hand, is the antithesis of something...which is nothing.


So..... if it's nothing, just space. Are humans or any life form able to move through it?
what happens when you enter this 'space'
I'm not too sure I'd agree with space being Nothing. Quantum Field Theory in fact shows that space is a boiling cauldron of virtual particles, and far from the "empty" void we used to think it was. Also, basic QFT calculations for the energy of the vacuum initially turn out to be infinite!

In addition, many of the new theories attempting unification are positing that higher dimensional "structures" existed before the Big Bang. One of them (M-Theory) has these branes floating around and when two of them collide at their edges, or overlap, a Universe like ours is born. So, as far as what existed before (the term used loosely, since there was no before the Big Bang, since time itself started at the instant of the Big Bang), I think the jury is still out on that one.
 
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CommonMan

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I know!......I know the answer!.......No wait, ...guess I don't. But I still know as much as everyone else. :)
 
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mkruck77

Guest
Re: if we caught up with the end of the universe ????

dougstuff":lwo2k5lb said:
There's a difference between 'space' and 'nothing'. If we're in a spatial universe that's expanding into nothing; the other side just doesn't exist. Example: There's something between us and the moon... space. If that space didn't exist, the moon would be touching us; there would truely be 'nothing' between us. And... since the universe IS something finite (according to the Big Bang), and the other side isn't occupied by anything (otherwise it would be part of our universe) - therefore it can't exist. It could be very possible to travel to the end of the universe just to find you're entering from the opposite side; a finite infinatum.
Seems logical. Since space contains time and matter contained in this outer fabric that contains the energy and all information related to it, somewhat like an expanding balloon. One could reason that if the outer conatains none of this then maybe there really is no existance in the outer, since what we consider existance is only contained with our space-time fabric or unified field. There probably is an answer, we're not evolved enough to figure it out.

BUT, this relates to the theory of multiple universes. If there are multiple universes, there must be some sort of dimensional divide (or one could stand to reason).
 
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Fallingstar1971

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OK I am going to chime in with my two cents on the issue (which, in reality isnt even worth that) LOL

OK

Did you guys ever see a movie call flatland. If not, watch it. I think it is relevant to this conversation

Long story short, I believe that there is a physical boundry to the edge of the Universe.

BUT there is a catch

Just like the square in two dimensional flatland could not look "up" until he was brought into the three dimensional world,(when he was lifted up, he passed through the boundry of his 2D world into our 3D (or 4D counting time) world. We cannot "look" in the direction leading to the edge of the Universe. It is speculated that we have access to 3 dimensions of space, and one dimension of time. The "edge" more than likely lies in the direction of a higher dimension that we, in 4d space, cannot see. We cannot even LOOK in that direction. (just like in 2D land, the square could not look "up". "Up" did not exist in 2D space

So yes, I believe that there is an "edge of the universe" but I also believe that it is impossible for us to view in 4D space.


This may seem like mumbo jumbo, but seriously, watch the movie. At least a hundred light bulbs popped on when I saw it. A lot of things seem to make sense when you factor in dimensions.

And just like the sphere was able to bring the square out of flatland and show him another dimension, unless a being from OUTSIDE our Universe (in a 5th dimension, the unseeable direction) took an inkling to remove us from space and SHOW us what is beyond, we, as the inhabitants of 4D space are destined to stay here. In our 4D Universe.

Star
 
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Booban

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darkmatter4brains":s2twq39v said:
Mitchrobbo":s2twq39v said:
So..... if it's nothing, just space. Are humans or any life form able to move through it?
what happens when you enter this 'space'
I'm not too sure I'd agree with space being Nothing. Quantum Field Theory in fact shows that space is a boiling cauldron of virtual particles, and far from the "empty" void we used to think it was. Also, basic QFT calculations for the energy of the vacuum initially turn out to be infinite!

In addition, many of the new theories attempting unification are positing that higher dimensional "structures" existed before the Big Bang. One of them (M-Theory) has these branes floating around and when two of them collide at their edges, or overlap, a Universe like ours is born. So, as far as what existed before (the term used loosely, since there was no before the Big Bang, since time itself started at the instant of the Big Bang), I think the jury is still out on that one.
Firstly, I'm not sure if Mitchrobbo is asking a trick question, but humans and other life forms can't move through it because we would then need a space suit because we need stuff to survive, space is not stuff.

And QTF, my questions would be what would happen if you removed the virtual particles from space? What would be left? Or what is in between these virtual particles? Is it not nothing?

I totally can't grasp infinite energy in a vacuum, but I am assuming your vacuum is the one with QTF particles.

I've never heard of branes, but how can you say nothing existed before the big bang when you said branes caused it. One would also have to ask what are the branes floating in? What was there before branes? What happens when you come to the edge of a brane...
 
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darkmatter4brains

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Booban":23cd3jkp said:
And QTF, my questions would be what would happen if you removed the virtual particles from space? What would be left? Or what is in between these virtual particles? Is it not nothing?
I think the answer to that question would basically be yes. Before QFT, space, or the vacuum, essentially was viewed as nothing (whatever "nothing" means). BUT, our view has evolved since then and, with the advent of QFT, we're discovering that the vacuum really isn't empty. Space is no longer nothing. To me, the statement "what would happen if you removed the virtual particles from space", basically means take QFT out of the picture and reduce it to an older, incomplete picture of what we used to think space was. But, we now know, the vacuum and these virtual particles sorta go hand in hand. You can't just take them out of the picture.

Also, since particles in quantum theories do not follow well defined paths, what does "in between" them even mean? They most likely have a probability of showing up anywhere in the space in question, and before you take the measurement to pin-point their position, they're essentially spread out all over the space in question. Each point in space would have a potential or probability assigned to it, for the particle to appear at that point. So where do you look for "nothing" here.

Also, look at Einstein's theory of gravity. It warps space. Well, how you can you warp "nothing"

Space is taking more and more of an ACTIVE role in physical theories and each day becomes less of a nothing and more of a something ;)

Booban":23cd3jkp said:
I totally can't grasp infinite energy in a vacuum, but I am assuming your vacuum is the one with QTF particles.

I've never heard of branes, but how can you say nothing existed before the big bang when you said branes caused it. One would also have to ask what are the branes floating in? What was there before branes? What happens when you come to the edge of a brane...
yes, it is the one with the QFT particles.

Well, you can't say before because "before" references something linear in time: before --> now ---> after. You must have time for that order to make sense. But, time was created at the instant of the Big Bang. There was no before the Big Bang, since there was NO time "before" the Big Bang.

A question that always bothered me about these branes also involves time. Branes oscillating, floating around and colliding all sound like TIME-dependent phenomena to me. How can you have oscillations and collisions w/o time? But, if these branes exist outside (before?) time, how can they be exhibiting this time-dependent phenomena?? I'm sure we're both probably missing some subtle ideas about the theory, though.

"What was there before branes?" Yep! .... and what caused the things that caused branes? And what caused the things, that caused the things, that caused branes? And what caused the things, that caused the things, that caused the things, that caused branes ...... ?????? :?
 
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darkmatter4brains

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Fallingstar1971":c2cvlxoc said:
We cannot even LOOK in that direction. (just like in 2D land, the square could not look "up". "Up" did not exist in 2D space

So yes, I believe that there is an "edge of the universe" but I also believe that it is impossible for us to view in 4D space.

Star
Neat idea, thanks for sharing. I was somewhat familiar with Flatland, but not that.
 
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Fallingstar1971

Guest
Another thing to consider would be time

If you have time, (Time is change) then even empty space with "nothing" MUST change if it is subjected to "time"

Even a total void completely empty of everything MUST change if it is subjected to "time"

If these things did not change, then you would not have "time"

So the simplest of answers would be "time" first, "Big bang" (change) second.

As the Universe grows, it is contaminating whatever is outside with "time" causing it to grow even more, (everything exposed to time becomes a part of our Universe) and at a very fast rate.

Star
 
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ohbill26

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the seeers always say looking back,where we came from.there must be some sense of direction,the term universe is a term of measure in past tense, where we are from ,looking back from here.Is the expanding ballone expanding in 3 directions or 4. We know in the long future we will become close neighbors with another gal going in the same direction from where we expanded from.I think i am getting a headache
 
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MeteorWayne

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Without proper punctuation and grammar, you post gave me a headache.
 
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Kpow

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I brought up similiar questions in thread in the unexplained section. If the universe was caused by a collision of branes then it was an event with a preceding cause. This absolutely implies that time existed pre-collision. If there is no time there can be no motion. I saw a documentary on time on nat geo and there was a professor from Cambridge that was discussing this brane theory. I wish I could remember his name.

Through what medium do these branes move? If they oscillate then do they oscillate at different frequencies? What sort of dimensions do they have? If they are infinite in length and even slightly out of phase then there would be an infinite number of collisions at every intersection of the branes. This would imply that there would be an infinite number of big bangs and potential universes. Could they have been 180 degrees out of phase and still colliding? Would the branes be repelled by the collision or would they pass through one another? The fact that they released so much energy implies to me that they must have mass.

sorry for all of the questions but this has been bugging me for awhile now.
 
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darkmatter4brains

Guest
Kpow":124rr6xw said:
I brought up similiar questions in thread in the unexplained section. If the universe was caused by a collision of branes then it was an event with a preceding cause. This absolutely implies that time existed pre-collision. If there is no time there can be no motion. I saw a documentary on time on nat geo and there was a professor from Cambridge that was discussing this brane theory. I wish I could remember his name.

Through what medium do these branes move? If they oscillate then do they oscillate at different frequencies? What sort of dimensions do they have? If they are infinite in length and even slightly out of phase then there would be an infinite number of collisions at every intersection of the branes. This would imply that there would be an infinite number of big bangs and potential universes. Could they have been 180 degrees out of phase and still colliding? Would the branes be repelled by the collision or would they pass through one another? The fact that they released so much energy implies to me that they must have mass.

sorry for all of the questions but this has been bugging me for awhile now.
I know, I've got all the same questions! and no answers ....

I'm pretty sure these branes can range up to being 9th dimensional structres as put forth in M-theory, so I think they are probably fairly exotic. They are supposed to have mass like you said. Also, M-Theory is supposed to be an 11th dimensional theory which unifies all the pre-existing string theories.

One of my problems with M-theory is that it is supposed to have over 100+ free parameters .... these are values you tweak just to get the theory to work. A true unifying theory, should have ZERO free parameters. So, I personally can't help but wonder if these guys are actually doing anything other than mathematical masturbation. Sorta like a sophisticated version of Ptolemy's epicycles. If I'm not mistaken, even Feynman had this feeling about String Theory. Only time will tell, as the theory is not yet complete. LHC might help out here too.
 
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