Where is the center of the universe?

[xrx1113]

OK I'm new to this site but i was wondering why: if we can see the red shift/blue shift of galixies and we know they are moving can't we tell by the degree of red shift/blue shift which direction they are going . If galixies are going in a strait line they are leaving where they were, if you drew lines backwards from them at some point they would all intersect at the center of the universe, dosn't that tell us where to point the telescope .
Am i totally wrong?

 

[Cosmo Novice]

OK I'm new to this site but i was wondering why: if we can see the red shift/blue shift of galixies and we know they are moving can't we tell by the degree of red shift/blue shift which direction they are going . If galixies are going in a strait line they are leaving where they were, if you drew lines backwards from them at some point they would all intersect at the center of the universe, dosn't that tell us where to point the telescope .
Am i totally wrong?

Yes.

If we trace all motion for everything we can see - the center is our galaxy - all galaxies are moving away from our galaxy. If we were in Andromeda then we would see Andromeda as the center.

This can only ever tell us the Observable Universes center - the point is this; most mass in the Universe has not moved a great deal since the Big Bang (barring individual kinematic motion which is almost negligible on large scales) , the BB was not an explosion in the traditional sense but can be explained by expansion of the scale factor.

Scale expansion does not require a center. You can attribute a center to the Observable Universe but as we know the Universe is much much larger than the Observable (even if still finite) then this has no relevance to the U as a whole.

If the Universe is infinite then it can't possibly have a center and if it infinite it is bounded in a way that any point can be the center.

The only centers are for observables and the only edges are for temporals, there can be no centers or edges to the Universe as a whole - it would contradict the Cosmological Principle.

 

[Chronos]

We can only measure radial velocity wrt earth, direction is much harder.

 

[petm1]

What part of seeing the universe as it appeared in the past is escaping notice here?

I like to link the past through the center connection of mass, like a compass needle that always points north, mass always points back to its common beginning inward.

 

[mjacobsca]

Is it possible that space expands in wirey filaments, or like branches of a tree, such that our observable universe is only one small branch on an enormous tree with no center? Do theories of inflation all assume a perfectly uniform inflation of space? I always wondered if it were possible, based on quantum effects, for *inflation to spread out like a tree, in a non-uniform way on large scales, and our small viewpoint only capable of seeing our tiny branch.

 

[ynot1]

If you follow Einstein's logic you have to consider the universe as 4 dimensional and treat all dimensions on an equal footing. So if you ask for the center of the universe you have to ask what is the center of time. This only makes sense from Feynman's perspective if you say matter moves in forward time and antimatter in reverse time. So it seems the center of time is at t=0, the big bang, where apparently spacetime originated. This would also represent the catastrophic end of antimatter, at least from its perspective, when it all converged on a single point. Since that time antimatter has been retreating back to its past, at least from our perspective. Strange.

 

[DaveC426913]

This only makes sense from Feynman's perspective if you say matter moves in forward time and antimatter in reverse time. So it seems the center of time is at t=0, the big bang, where apparently spacetime originated. This would also represent the catastrophic end of antimatter, at least from its perspective, when it all converged on a single point. Since that time antimatter has been retreating back to its past, at least from our perspective. Strange.

Antimatter does not move backward in time. The above statements are all incorrect.

 

[salvestrom]

Antimatter does not move backward in time. The above statements are all incorrect.

Isn't the middle bold statement only half incorrect? It may not have occurred at t=0, but it did happen.

 

[DaveC426913]

Isn't the middle bold statement only half incorrect? It may not have occurred at t=0, but it did happen.

What? That antimatter came to an end at t=0? No.

You mean why there is such a paucity of it in the universe today? Fair enough.

 

[salvestrom]

What? That antimatter came to an end at t=0? No.

You mean why there is such a paucity of it in the universe today? Fair enough.

My statement was pretty clear that it didnt happen at t=0. Yes, I was referring to the fact it is supposed to have happened at some point after, leading to it being largely absent from today's universe.

 

[ynot1]

Further clarification: Per http://www.upscale.utoronto.ca/PVB/Harrison/AntiMatter/AntiMatter.html

"An electron traveling backwards in time is what we call a positron."

 

[DaveC426913]

My statement was pretty clear that it didnt happen at t=0. Yes, I was referring to the fact it is supposed to have happened at some point after, leading to it being largely absent from today's universe.

ynot1's comments were clearly about moving backward in time toward the Big Bang. Which is completely wrong.

 

[ynot1]

My statement was pretty clear that it didnt happen at t=0. Yes, I was referring to the fact it is supposed to have happened at some point after, leading to it being largely absent from today's universe.

Largely absent? If antimatter ended t=0 we are now seeing it before it ended. Antimatter is now backing away from gravitational fields as it is traveling in backwards time. That means as matter separates antimatter backs off even faster because of its antigravitational effects. So it seems if it's out there it's way out there. And the more of it that moves away it could be the faster the universe appears to expand. A possibility for the accelerating expansion. I realize it is difficult to think backwards in time.

 

[salvestrom]

ynot1's comments were clearly about moving backward in time toward the Big Bang. Which is completely wrong.

Which I understand. But you highlighted "the catastrophic end of antimatter" and finished by stating all the above comments are incorrect. I was only looking to point out that the matter-antimatter annihilation had occured, only not when proposed by the poster. Someone else reading this might have been unaware of this.

 

[minio]

Largely absent? If antimatter ended t=0 we are now seeing it before it ended. Antimatter is now backing away from gravitational fields as it is traveling in backwards time. That means as matter separates antimatter backs off even faster because of its antigravitational effects. So it seems if it's out there it's way out there. And the more of it that moves away it could be the faster the universe appears to expand. A possibility for the accelerating expansion. I realize it is difficult to think backwards in time.

Well I have to admit that I don't follow, but as matter and antimatter annihilate - wouldn't then this theory imply, that somewhere between big bang and end of time there will be "great annihilation"?

 

[salvestrom]

Largely absent? If antimatter ended t=0 we are now seeing it before it ended. Antimatter is now backing away from gravitational fields as it is traveling in backwards time. That means as matter separates antimatter backs off even faster because of its antigravitational effects. So it seems if it's out there it's way out there. And the more of it that moves away it could be the faster the universe appears to expand. A possibility for the accelerating expansion. I realize it is difficult to think backwards in time.

Anti-matter was largely wiped out after t=0. I have never heard anyone suggestthat antiparticles are time-reversed before.

Has anyone else viewed ynot's link? I can't tell what's actual physics, what's being hijacked and what's getting made up.

Edit: in fact, the quote he gives along with the link is presented as if Feynman proposed it. I find that unlikely.

 

[ynot1]

Anti-matter was largely wiped out after t=0. I have never heard anyone suggestthat antiparticles are time-reversed before.

Has anyone else viewed ynot's link? I can't tell what's actual physics, what's being hijacked and what's getting made up.

Edit: in fact, the quote he gives along with the link is presented as if Feynman proposed it. I find that unlikely.

Actually it might have been someone else as discussed at http://en.wikipedia.org/wiki/Retrocausality:
"Feynman, and earlier Stueckelberg, proposed an interpretation of the positron as an electron moving backward in time,[15]"

 

[Vanadium 50]

"An electron traveling backwards in time is what we call a positron."

Sorry, that's not the case. This was proposed by Feynman in 1948, and falsified by Christiansen, Cronin, Fitch and Turlay in 1964. For some reason, this idea Will Not Die, despite having been known to be wrong for almost half a century.

 

[nonequilibrium]

Sorry, that's not the case. This was proposed by Feynman in 1948, and falsified by Christiansen, Cronin, Fitch and Turlay in 1964. For some reason, this idea Will Not Die, despite having been known to be wrong for almost half a century.

Interesting. We haven't discussed this topic in any of my university classes yet, but I have heard this (apparently false) statement in the popular science regions many times over. I was just wondering, is the idea of their disproving easy to understand? Or where can I read up on this?

 

[salvestrom]

Interesting. We haven't discussed this topic in any of my university classes yet, but I have heard this (apparently false) statement in the popular science regions many times over. I was just wondering, is the idea of their disproving easy to understand? Or where can I read up on this?

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).

 

[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).

Stranger yet. I remember a Feynman video where he was waving his hands around illustrating positrons going around in a synchrotron, I think it was, in the reverse direction of an electron. It seems there is no "arrow of time", rather "arrows" of time. That is we view time going in both directions. In our case apparently the arrows are pointing inward - forward for us, backwards for antimatter. I certainly wouldn't make any claims about faster than light particles however.

From the Einstein point of view all 4 dimensions should be treated on an equal footing. So from our perspective there is always an up, down, left, right, forward, and backward. If time is to be treated equivalently there must also be a forward and backwards. Actually it's a matter of symmetry - in all 4 dimensions.

 

[salvestrom]

Stranger yet. I remember a Feynman video where he was waving his hands around illustrating positrons going around in a synchrotron, I think it was, in the reverse direction of an electron. It seems there is no "arrow of time", rather "arrows" of time. That is we view time going in both directions. In our case apparently the arrows are pointing inward - forward for us, backwards for antimatter. I certainly wouldn't make any claims about faster than light particles however.

From the Einstein point of view all 4 dimensions should be treated on an equal footing. So from our perspective there is always an up, down, left, right, forward, and backward. If time is to be treated equivalently there must also be a forward and backwards. Actually it's a matter of symmetry - in all 4 dimensions.

Time has a forward and back. We, and the universe, have been moving through that dimension from its apparent origin at t=0 up until the present date, from which we will move on. The uniqueness of the time dimension is the apparent inability to move backwards along it. However, that "back" has been traveled along nonetheless as our past. I have watched a 1950's/60's lecture of Feynman entirely dedicated to explaining the arrow of time and entropy. He never mentioned anything about antimatter and traveling back through time.

Since the universe encompasses all space and all time, it could be argued from a universal perspective all 4 dimensions have been traveled and explored equally. There would then be no requirement that any substructure of it, ourselves or antimatter, need be able to travel back in time in order to treat the 4 dimensions equally.

 

[Chronos]

Anti-time, like anti-gravity probably is probably unphysical. Gravity is an integer spin force, which does not have an anti equivalent. A photon is also an integer spin force and has no anti equivalent. Only half spin entities, like matter, have an anti equivalent so far as we know. If there is such a thing as a 'chronon' it almost surely is an integer spin force.

 

[ynot1]

Anti-time, like anti-gravity probably is probably unphysical. Gravity is an integer spin force, which does not have an anti equivalent. A photon is also an integer spin force and has no anti equivalent. Only half spin entities, like matter, have an anti equivalent so far as we know. If there is such a thing as a 'chronon' it almost surely is an integer spin force.

I thought the photon is its own anti-particle.

 

[ynot1]

Time has a forward and back. We, and the universe, have been moving through that dimension from its apparent origin at t=0 up until the present date, from which we will move on. The uniqueness of the time dimension is the apparent inability to move backwards along it. However, that "back" has been traveled along nonetheless as our past. I have watched a 1950's/60's lecture of Feynman entirely dedicated to explaining the arrow of time and entropy. He never mentioned anything about antimatter and traveling back through time.

Since the universe encompasses all space and all time, it could be argued from a universal perspective all 4 dimensions have been traveled and explored equally. There would then be no requirement that any substructure of it, ourselves or antimatter, need be able to travel back in time in order to treat the 4 dimensions equally.

Interesting. Does all time include the future?

 

[salvestrom]

Interesting. Does all time include the future?

This is a question of view point. Is the universe entirely determinstic or random?

 

[scottbekerham]

This is a question of view point. Is the universe entirely determinstic or random?

I believe that the universe is deterministic . If you apply quantum mechanics on the universe then you can consider the universe as a wavefunction whose evolution is of course deterministic (As the equation of motion is A partial differential equation ) .

 

[scottbekerham]

In string theory , If you put a brane in spacetime then this brane breaks spacetime rotational and translational invariance so there should be preferred directions in spacetime also if you imagine a universe with concentric D-branes then there should be a center of the universe . Is this correct?

 

[ynot1]

I believe that the universe is deterministic . If you apply quantum mechanics on the universe then you can consider the universe as a wavefunction whose evolution is of course deterministic (As the equation of motion is A partial differential equation ) .

Yes I believe our ultimate fate has been determined at least until the universe is reborn in the next big bang.

 

[ynot1]

Incorrect: it is expanding at the same rate everywhere.

Implying the accelerated expansion is the same everywhere. Interesting.

 

[ynot1]

think space as a balloon. before "big bang" think if the balloon has no air then blow it up then find the center...you can't find the center. if it has cent it would contradict infinite universe

Is there a problem with this contradiction?

 

[ynot1]

Because the overall density of the whole bigbang matter is thinning, and a relativistic view of this means time is accelerating and space is expanding. It is a twofold thing that results in acelerated expansion.

Note from a Newtonian view if the overall matter density is thinning and the force of expansion is constant then the expansion must be accelerating.

 

[ynot1]

Because matter is distributed approximately the same everywhere. This is actually only true on large scales, but the same can also be said about the expansion. The solar system and the galaxy isn't expanding, at least not at the same rate as the cosmological expansion.

Yes gravitationally bound objects like galaxies aren't expanding as I understand it. Rather they are collapsing and forming stars, planets, black holes, etc. Their ultimate fate is recycling by black holes into radiation.

 

[ynot1]

The paint balloon analogy does not seem to fit. When the balloon hits the ground, it is subject to asymmetrical forces. The bottom will likely break while the top is intact. The paint will be emerging from a non-spherical container which flexes in process. Shards of rubber block the flow of paint.

A more approximate analogy might be a perfect sphere of paint sitting in deep space, with a tiny symmetrical explosive charge placed at its center that releases its energy in about 10exp-40 second. I suspect that this would produce an evenly distributed pattern of paint.

As for the WMAP images, I've looked at them again and again and keep wondering why astrophysicists insist that they show a symmetrical energy distribution. There are blobs and lumps all over the place. I make it a point to keep in practice recognizing such things by studying a centerfold image monthly. Haven't lost my skills. The WMAP images look to me like the result of a sloppy, asymmetrical paint balloon explosion.

Thanks for your reply. Please don't worry about sharing your thoughts with me. I don't treat PF like a physics class where the answers are in the professor's private supplementary text. The PF is a place where awesome ideas could be formed if people share their honest thoughts and best ideas, post interesting questions and expect a variety of answers.

These astrophysicists are only aboit 99.9% correct. If the distribution were perfectly symmectric it wouldn't be possible for particles to aggregate and form galaxies. The variability would be due to quantum uncertainty. Since this is very small you could guesstimate the size of the original volume as about 1000 Planck volumes.

 

[ynot1]

Me too! I suspect that your style of humor will generally be lost on those who take themselves seriously.



I find the method by which we've derived BB theory fully plausible. But, where it gets us does not feel right. I don't mean feeling in the emotional sense, but in the logical sense.
It seems to me that if we got there from here, we should be able to get here from there. That does not appear to be the case. This makes BB theory logically asymmetrical.

Then there is the persistent observation that we live in a cause-effect universe; where then is the Big Bang's cause?

50 years ago I gave up my belief in God for several reasons, one in particular being the absurd motivations attributed to this entity for the creation of mankind. BB theory seems to me to suffer from the equivalent failing--- lack of plausible cause.



Wherever we start can be fairly regarded as an hypothesis. Whether an hypothesis becomes the core of effective physical understanding, or the basic dogma of another religion, depends upon what we do with it.

If we can derive it mathematically from a bit of observational evidence, and test it empirically, then it's usually science. If it predicts something we'd otherwise not have known, then it is almost certainly science.

But if we insist that an hypothesis came inscribed on golden tablets, since removed to heaven, and cannot possibly test it, then it's religion.

If we wake up some morning suddenly knowing the secrets pf the universe, and wrap a bunch of coherent polysyllabic words around our notions but never bother to test any assumptions or trouble ourselves with predictions, we've got another philosophy.

IMO BB theory is in the neverland of what I'd call, physical theology. While derived by scientists, it lacks some properties which we normally associate with sound science. Moreover, the Big Bang's mysterious precursor shares more characteristics with the God of Christianity than with any known physical phenomenon. (Mysterious or non-existent origin, containing/creating all matter and energy, yet doing so without credible cause or purpose.)

Something's not right with BB theory.

Likely the credible cause is quantum uncertainty. Nothingness is a state of certainty and disallowed by quantum uncertainty. As to how the laws of nature came about, that would be the real question in my mind.

 

[ynot1]

I believe that the universe is deterministic . If you apply quantum mechanics on the universe then you can consider the universe as a wavefunction whose evolution is of course deterministic (As the equation of motion is A partial differential equation ) .

Certainly the wavefunction is deterministic. But its magnitude describes a probability.

 

[Tanelorn]

Greylorn Re:

Wherever we start can be fairly regarded as an hypothesis. Whether an hypothesis becomes the core of effective physical understanding, or the basic dogma of another religion, depends upon what we do with it.

If we can derive it mathematically from a bit of observational evidence, and test it empirically, then it's usually science. If it predicts something we'd otherwise not have known, then it is almost certainly science.

But if we insist that an hypothesis came inscribed on golden tablets, since removed to heaven, and cannot possibly test it, then it's religion.

If we wake up some morning suddenly knowing the secrets pf the universe, and wrap a bunch of coherent polysyllabic words around our notions but never bother to test any assumptions or trouble ourselves with predictions, we've got another philosophy.

IMO BB theory is in the neverland of what I'd call, physical theology. While derived by scientists, it lacks some properties which we normally associate with sound science. Moreover, the Big Bang's mysterious precursor shares more characteristics with the God of Christianity than with any known physical phenomenon. (Mysterious or non-existent origin, containing/creating all matter and energy, yet doing so without credible cause or purpose.)

Something's not right with BB theory.

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 have also had similar problems with near infinite universe size then, as well as near infinite universe size now, and yet the creation event is supposed to be a quantum event which I associate with things so small that their position and momentum can't even be accurately determined. I very much suspect I need to learn a lot more about this.

Cosmologists are trying to explain the observations that have been made and then they extrapolate as far back as they can from these observations. The further they extrapolate the more speculative they become, and we could perhaps sometimes do with more information from them regarding just how speculative they are being.

As to how the laws of nature came about, that would be the real question in my mind.

Yes, that's one of them. As for why, well perhaps "The Truman show" helps answer that? :)
Heaven for a Cosmologist, me included, would likely be a place where they could learn the answers to all these questions.

 

[ynot1]

But if we insist that an hypothesis came inscribed on golden tablets, since removed to heaven, and cannot possibly test it, then it's religion.

Interesting in my view the turning point in man's evolution may be the sun god - the corona. Four footed creatures, when the skies turned dark, probably thought it was time for a nap. But some bipeds looked up and saw the corona and the only way they could interpret it was as a sun god. This earth-moon-sun geometry may be essential for the evolution of man. If the geometry was off by maybe 3% the bipeds may have never bothered to lookup and begin to wonder. And so now we build telescopes and still wonder. Point being science may owe it all to some form of mystery.

 

[Drakkith]

Interesting in my view the turning point in man's evolution may be the sun god - the corona. Four footed creatures, when the skies turned dark, probably thought it was time for a nap. But some bipeds looked up and saw the corona and the only way they could interpret it was as a sun god. This earth-moon-sun geometry may be essential for the evolution of man. If the geometry was off by maybe 3% the bipeds may have never bothered to lookup and begin to wonder. And so now we build telescopes and still wonder. Point being science may owe it all to some form of mystery.

Unlikely. Solar eclipses are so rare for any spot on the surface and the Sun itself is so important to everyday life that it is much more likely that a Sun God was made just out of a need to try to explain what the Sun was. In any case science is 100% about finding out the "mystery" of the universe and explaining it using the scientific method.

 

[ynot1]

Unlikely. Solar eclipses are so rare for any spot on the surface and the Sun itself is so important to everyday life that it is much more likely that a Sun God was made just out of a need to try to explain what the Sun was. In any case science is 100% about finding out the "mystery" of the universe and explaining it using the scientific method.

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.

 

[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?