Where is the center of the universe?

[ynot1]

Hmm. Reading thru the wikipedia page on antimatter the most straightforward disproof of them traveling backward in time is that scientist create billions of them these days and we can see them. I'm pretty sure you're not supposed to be able to see something moving backward in time (a trait attached to tachyons).

Point being nothing could be created moving backwards in time because it would then have to be immediately destroyed. Feynman says somewhere that time reversibility is possible on the macro scale but improbable. So perhaps when you reverse time events happen in a more probabilistic fashion. You might say quantum uncertainty takes over and precludes events from recurring precisely as they occurred initially. Most physical laws allow time reversibility but I don't think time reversibility is applicable on the quantum scale. Maybe this has something to do with CP violation but that stuff is way over my paygrade.

 

[salvestrom]

Most physical laws allow time reversibility

Do they? Although any physical reaction can be modeled backward as well as it can be forward, I'm not sure saying 'allowed' is accurate. The laws of physics are mathematical descriptions, not facilitators. The question isn't can we model two planets uncolliding (sure we can), it is: can two planets uncollide?

 

[Drakkith]

Could be but note rarity is an essential part of the mystery. It separates the believers from the unbelievers. Nobody is really surprised when the sun comes up in the morning.

I don't see it quite that way, but I won't elaborate further as it would be pretty far off topic.

Greylorn Re:

I have had similar misgivings, perhaps because the BB theory isn't even complete yet? Also there is always going to be one more level of cause and effect. e.g. what caused the Branes that caused the BB? etc. Saying that however, it is still good to learn as much as possible about each of these steps regardless.

I'm not sure what you mean by "complete". There are limitations with ALL theories. One of the main ones with the BB theory is that it stops working past a certain point in the past near the "Big Bang".

 

[ynot1]

Do they? Although any physical reaction can be modeled backward as well as it can be forward, I'm not sure saying 'allowed' is accurate. The laws of physics are mathematical descriptions, not facilitators. The question isn't can we model two planets uncolliding (sure we can), it is: can two planets uncollide?

Yes, per Feynman, although the probability of such an event is pretty remote.

 

[salvestrom]

Yes, per Feynman, although the probability of such an event is pretty remote.

"Do they?" was rhetorical sarcasm over your use of the word "allow".

 

[DaveC426913]

"Do they?" was rhetorical sarcasm over your use of the word "allow".

I would say he has used the word correctly, and agree with his statement.

 

[salvestrom]

I would say he has used the word correctly, and agree with his statement.

Correct useage or not, I find the use of the word interesting.

 

[rglong]

I am just putting what my thoughts are
since all finite matter has a center and the universe is finite, that it must have a defined center even if you are on a lake and look around and can't see the shore as a frame of referance, the lake still has a center. Our inablity to find the center does not mean that the center does not exist. If the universe does not have a center then it cannot be finite.

 

[ynot1]

If the universe does not have a center then it cannot be finite.

So where would you find the center of an infinite universe, if such a thing exists? Or did I miss something?

 

[DaveC426913]

I am just putting what my thoughts are
since all finite matter has a center and the universe is finite, that it must have a defined center even if you are on a lake and look around and can't see the shore as a frame of referance, the lake still has a center. Our inablity to find the center does not mean that the center does not exist. If the universe does not have a center then it cannot be finite.

This is not at all true.

You are standing on the surface of the Earth - a 2-dimensional plane with a finite area. Where is the centre of the Earth's surface?

 

[SHISHKABOB]

This is not at all true.

You are standing on the surface of the Earth - a 2-dimensional plane with a finite area. Where is the centre of the Earth's surface?

would it be that there is no center or that every point is the center? Or is there a difference between those two?

 

[rglong]

The center of the Earth's surface is not the center of the Earth as a whole. A solid 3-d shape like the Universe does have a center. And the center of the Earth's surface could be said to have infinite centers as each point can be reached by going around the Earth, and the path you follow has a midpoint. But as I said, the Earth does have a center. Also, the surface of the Earth can not be made into a 2-d shape, the surface of the Earth is also a sphere and the center of the spheres mass would be at the center of the sphere. If you laid the Earth out flat, then it would have a defined center since you would have to chose a latitude or longitude to define as the edge, no matter where you cut a globe and lay it out, you will end up with a center.

 

[rglong]

would it be that there is no center or that every point is the center? Or is there a difference between those two?

If you view it at a single point, the center would be the opposite pole to you. If you did it for every point on a sphere, there would be infinite centers on the sphere.

 

[rglong]

So where would you find the center of an infinite universe, if such a thing exists? Or did I miss something?

This is presuming that the universe is finite. If it were infinite, then there would be no center.

 

[Tanelorn]

If the Universe is not truly infinite would this suggest that there is something else besides the Universe?
I don't mean the observable universe here, I mean the whole Universe which is a continuum of our own observable Universe.
By something else I mean more Universes separate to our own or perhaps something in which our Universe is contained in some way.

 

[DaveC426913]

would it be that there is no center or that every point is the center? Or is there a difference between those two?

The centre point of a surface is a special, privileged point that no other point on the surface has. There is no point on the surface of a sphere that is privileged, therefore, no point is the centre.

The center of the Earth's surface is not the center of the Earth as a whole.

Do you grant that the surface of the Earth is finite in extent, yet has no centre?

A solid 3-d shape like the Universe does have a center.

What makes you say that?

Some 3D shapes have centres. That does not mean all do.

And the center of the Earth's surface could be said to have infinite centers

Then none are unique. Thus, they cannot be centre.

If you laid the Earth out flat, then it would have a defined center since you would have to chose a latitude or longitude to define as the edge, no matter where you cut a globe and lay it out, you will end up with a center.

That is correct. The moment you artificially divide it up, providing artificial boundaries, you make artificially privileged points. You would no longer have a surface of a sphere.

If you go nuts with your scissors and cut the Earth's flattened shape into confetti, then your shape will have straight edges and acute vertexes. Does that say anything at all about the original shape of the Earth's surface before you mangled it? Does it mean "the surface of the Earth has straight edges and vertices"?

 

[DaveC426913]

If the Universe is not truly infinite would this suggest that there is something else besides the Universe?

It does not suggest it, no.

Nor does it in-and-of-itself rule out there being something else - but not being infinite does not suggest there is anything else.

 

[Tanelorn]

Well it is hard to imagine that everything that is or ever can be is finite. There again it is difficult to imagine infinite as well.
It is also hard to imagine that there is any final level of reality or structure, since everything we know of in our everyday life is contained inside or is a part of something else; sub atomic particles, atoms, molecules, planets, solar systems, galaxies, clusters etc.

 

[DaveC426913]

Well it is hard to imagine that everything that is or ever can be is finite. There again it is difficult to imagine infinite as well.

We don't have to imagine it. Imagination is flawed by definition, since it depends on things we've experienced before.

The mathematics shows us. It is the only accurate model.

 

[salvestrom]

We don't have to imagine it. Imagination is flawed by definition, since it depends on things we've experienced before.

The mathematics shows us. It is the only accurate model.

What a bizarre thing to say. I'm pretty sure I've never experienced a thousand mauruading snargle-bangs from Ceti-Prime Zeta demanding my left shoe and some yo-yos. (I may have experienced Douglas Adams at some point).

And an infinite universe is not the only model, you say this yourself. It's also possible that the universe is finite and unbounded. It's also possible there is an outside to what we currently consider the universe, regardless of whether the model requires it.

The moment you consider anything you cannot currently see, you are imagining.

 

[Chronos]

There is nothing imaginary about the math. Get used to it.

 

[salvestrom]

There is nothing imaginary about the math. Get used to it.

Imaginary numbers? Virtual particles? Besides, imagination and imaginary are not the same thing.

 

[Chronos]

Blue moon and bleu cheese? Blue and bleu are not the same thing. Your point escapes me.

 

[salvestrom]

Blue moon and bleu cheese? Blue and bleu are not the same thing. Your point escapes me.

Nobody said anything about math being imaginary, only you brought it up.

 

[Tanelorn]

I strongly believe it is not just about the math! The Universe is Physical and not just a computer running a bunch of equations.


Consider x = y * z, it is meaningless and tells us nothing.

However when we add the Physics we get Ohm's law. The Physics allows us to understand what is really going on and the equation allows us to calculate specific numbers.



Back to the earlier discussion; nothing beyond the Observable Universe can be proven to exist.
So we have to extrapolate from the conditions inside our own Universe and assume that homogeneity and isotropy apply beyond it.
For any kind of presumed reality beyond that, we have to list all possible possbilties, or just give up and say we can't do this.
I very much doubt that the rest of reality is blue cheese, but it ok to write it down in a brainstorming session, we can add the odds later.

 

[DaveC426913]

What a bizarre thing to say. I'm pretty sure I've never experienced a thousand mauruading snargle-bangs from Ceti-Prime Zeta demanding my left shoe and some yo-yos. (I may have experienced Douglas Adams at some point).

And an infinite universe is not the only model, you say this yourself. It's also possible that the universe is finite and unbounded. It's also possible there is an outside to what we currently consider the universe, regardless of whether the model requires it.

The moment you consider anything you cannot currently see, you are imagining.

I didn't say you can't imagine things, I simply said it depends on things you're already experienced. This is why when you said "...it is hard to imagine that everything that is or ever can be is finite. There again it is difficult to imagine infinite as well..." I pointed out that our imaginations are flawed. Perhaps a better word would have been 'limited'.

You're having difficulty, because it is totally outside your realm of experience. The universe is not obliged to make sense to you.

 

[Tanelorn]

The human mind is pretty good at brainstorming and perhaps one of these extra-universe solutions is close to correct, which is why I like to read them all. I have a variation of the colliding branes involving two particles in an infinite space which eventually collide and BB. The problem is this is a localised explosion type BB, whereas we need the BB to occur everywhere in space simultaneously and I believe this requires extra dimensions like the branes hypothesis - unless I am misunderstanding the idea.

 

[salvestrom]

I didn't say you can't imagine things, I simply said it depends on things you're already experienced. This is why when you said "...it is hard to imagine that everything that is or ever can be is finite. There again it is difficult to imagine infinite as well..." I pointed out that our imaginations are flawed. Perhaps a better word would have been 'limited'.

You're having difficulty, because it is totally outside your realm of experience. The universe is not obliged to make sense to you.

Well, for one, I'm not the poster who you are quoting in brackets. :P

I'm not having difficulty. I favour one over the other at present because neither makes a tremendous difference to the model and I prefer finite and unbound. I also never said the universe was oblidged to do anything for me.

I think the statement of imagination being flawed is erroneous. Limited is even worse. I apply the word imagination the moment we consider anything that isn't present, particularly the future.

Is imagination rooted in past experience? Not entirely. Is it able to produce something "unreal". Definitely. But so can mathematics. Dragons versus 11-dimensions. Ooh. 11-dimensional space dragons. I have to go write that down. /hug

 

[SHISHKABOB]

can you imagine something that is entirely unrelated to something that you have once experienced? It's like trying to imagine another color.

 

[ynot1]

can you imagine something that is entirely unrelated to something that you have once experienced? It's like trying to imagine another color.

No. You must have experienced the ingredients going into images before you can form an image. The re-configuration of these ingredients is where creativity comes into play.

 

[Cosmo Novice]

I think say we are limited by a combination of our sensory experiences and our own cognition and consciousness, which is the essentially same for all animals just at varying levels of awareness and intelligence.

My arguing point would be this, we can imagine things inside our experience; like seeing in 8vision like a spider, but then try to imagine what it would be like to fly by echo location like a bat without relating it to little images on a screen and a sweeping light...

What I guess I am saying is that we can imagine any random configuration of events - as long as they are descriptive in a way that confirms with our sensory understanding and/or our cognition and consciousness. Sight, touch, smell, sound, taste, thoughts and emotions are the things we understand, we cannot imagine anything that is not one of those without using an analogy.

I think this applies to when we think about anything prior to the Universe, or prior to the original cause, even if its turtles all the way down...

 

[salvestrom]

I think say we are limited by a combination of our sensory experiences and our own cognition and consciousness, which is the essentially same for all animals just at varying levels of awareness and intelligence.

My arguing point would be this, we can imagine things inside our experience; like seeing in 8vision like a spider, but then try to imagine what it would be like to fly by echo location like a bat without relating it to little images on a screen and a sweeping light...

What I guess I am saying is that we can imagine any random configuration of events - as long as they are descriptive in a way that confirms with our sensory understanding and/or our cognition and consciousness. Sight, touch, smell, sound, taste, thoughts and emotions are the things we understand, we cannot imagine anything that is not one of those without using an analogy.

I think this applies to when we think about anything prior to the Universe, or prior to the original cause, even if its turtles all the way down...

I'd argue that science is no better position than imagination regardless of how either are compiled.

Infinity is, itself, a millenia old imagined concept.

 

[DaveC426913]

Well, for one, I'm not the poster who you are quoting in brackets. :P

Apologies.

I think the statement of imagination being flawed is erroneous. Limited is even worse. I apply the word imagination the moment we consider anything that isn't present, particularly the future.

Please, don't take my statement out of context. You're responses sound as if you think I said we don't have an imagination.

I am simply saying that not being able to imagine something (such as an infinite universe) is a terrible reason for doubting its existence.

 

[salvestrom]

I am simply saying that not being able to imagine something (such as an infinite universe) is a terrible reason for doubting its existence.

Totally. <3

I wasn't taking it that you had suggested we don't have one - that'd be just plain weird - only taking exception to what seemed like a sidelining, or put down. But I think we are on the same page now. =D

 

[Tanelorn]

Apologies.
I am simply saying that not being able to imagine something (such as an infinite universe) is a terrible reason for doubting its existence.

Dave, I say that things are difficult to imagine, but I never intended to be understood that I doubt its existence. For me the two are separate. I just can't imagine anything infinite.

Actually the biggest reason I have for suspecting the Universe is spatially finite is that it is temporally finite. Again no proof just a hunch.