Where was the big bang singularity?

jumpjack
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If all galaxies originated from big-bang, and if currently galaxies are still moving away one from the other, shouldn't it be possible to determine also where they are moving away from? i.e.where the big-bang-singularity was?
 
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No. the nature of an explosion is such that every particle appears to be the centre of expansion.
 
AJ Bentley said:
No. the nature of an explosion is such that every particle appears to be the centre of expansion.

I don't get it.
In an explosion , all particles come from the same point and each one goes to a different point.
At least, seen from outside. How does a particle see its own motion? Can "she" see it w.r.t the outside reference system?
 
jumpjack said:
I don't get it.
In an explosion , all particles come from the same point and each one goes to a different point.
At least, seen from outside. How does a particle see its own motion? Can "she" see it w.r.t the outside reference system?

Balloon analogy. Think of a bunch of dots marked on a balloon. The balloon expands and every point on the surface of the balloon recedes from every other point. In fact, the rate of recession between any two dots is directly proportional to their distance.

Note that the surface of the balloon has no centre; no dot can claim to be nearer a centre than any other dot. When the balloon was (ideally) zero-size, all dots were at the centre.
 
DaveC426913 said:
Note that the surface of the balloon has no centre;

When the balloon was (ideally) zero-size, all dots were at the centre.

The two sentences do not match!

Indeed, all dots on the surface were previously all in a single point: the centre of balloon VOLUME.

So, where is this point in the Universe? Can we determine it? How?

Or maybe the balloon surface (2d) represents our 3d universe?!?

Could we determine the "centre position" if it was in the 4th (?) dimension?

Can Flatland inhabitants determine position of objects in the 3d space surrounding them?
 
jumpjack said:
Or maybe the balloon surface (2d) represents our 3d universe?!?
Correct.

jumpjack said:
Could we determine the "centre position" if it was in the 4th (?) dimension?
As it turns out, the extra dimension is not actually required for the math to work out. The balloon doesn't need a 3rd dimension, the universe doesn't need a 4th, and neither need a place for the centre to be.
 
DaveC426913 said:
Correct.


As it turns out, the extra dimension is not actually required for the math to work out. The balloon doesn't need a 3rd dimension, the universe doesn't need a 4th, and neither need a place for the centre to be.
maybe our math doesn't need the additional dimension, but the Universe has it! The balloon HAS a 3rd dimension!
 
jumpjack said:
maybe our math doesn't need the additional dimension,
I'm not saying "just" the math doesn't need the dimension; I'm saying the 3D expansion of the universe works just fine mathematically without the need to resort to a 4th dimension.

Thing is, it's virtually impossible for the layperson (non-mathematicians) for wrap their head around it, which is why we resort to simpler analogies.

jumpjack said:
but the Universe has it! The balloon HAS a 3rd dimension!
That's why it's an analogy. Not everything about the balloon analogy is translatable to the universe.
 
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jumpjack said:
maybe our math doesn't need the additional dimension, but the Universe has it! The balloon HAS a 3rd dimension!

I'm not an expert of this but perhaps I can provide an explanation that will help.

The first thing you have to understand is that every direction we look, we can see for 13.7 billion light years. This means one of two things. WE are at the center of the universe OR the Universe is much larger than we can see and it is roughly uniform in every direction.

Every time we say we're at the center of the Universe we are proven wrong. This is why we call what we see, "the observable universe". Base on our observations of the observable universe, there is no edge and since there is no edge, it could be infinite or finite and wrap around itself. If you take the entire Earth and you put an ant hill on one small part of it then ask the ant where the center of the Earth is, will he be able to tell you an answer or will he just say that the Earth goes on forever?

Basically, you're asking a question which no one can really answer. The data from the CMB seems to show that everything is roughly uniform in all direction. This would imply that there is no center because a center would by definition be where the big bang originated and it would show up as hotter in the survey. Again, if there is a center that is outside of our observable universe, we would expect to see that one direction is cooler (whichever direction is the exact opposite of the center). It is of course possible that the center of the universe is so far away that we can't see the extremely small decrease in temperature with our current equipment.

In other words, based on current observations, the universe started with everything at a single point in space and everything expanded from there. That's the only way to account for current observation.

I hope that helped.
 
  • #10
I think the word "where" is inappropriate to use when describing the Big Bang. When we usually use "where", we are implying some location in 3-D space in our Universe but the Big Bang was the start of our Universe and I suspect just prior to the Big Bang there was no space but rather something qualitatively different and therefore our concept of space, of location, distance, size, volume, area, location, and other similar metrics are not applicable and cannot be used to describe the instant of the Big Bang and therefore "where" it occurred.
 
  • #11
Q. Where was the big bang singularity.

A. Everywhere

Skippy
 
  • #12
Here is an article that throws around a plethora of ideas except the ID one.
http://www.tomcoyner.com/before_the_big_bang_there_was__.htm
 
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  • #13
skippy1729 said:
Q. Where was the big bang singularity.

A. Everywhere

Skippy

A singularity was everywhere ?

Then everywhere was / is a singularity. Very confusing.
 
  • #14
alt said:
A singularity was everywhere ?

Then everywhere was / is a singularity. Very confusing.

Go back to the balloon analogy. When the balloon was uninflated (ideally, a point), all dots on the balloon were in the same place. None had a preferred location. When the balloon began to expand, all dots that were at the initial point of expansion moved away from that point. Still, no dot has a preferred location. And no one dot is nearer the initial point of expansion than any other.
 
  • #15
DaveC426913 said:
Go back to the balloon analogy. When the balloon was uninflated (ideally, a point), all dots on the balloon were in the same place. None had a preferred location. When the balloon began to expand, all dots that were at the initial point of expansion moved away from that point. Still, no dot has a preferred location. And no one dot is nearer the initial point of expansion than any other.

OK, but when the balloon was uninflated all the dots were at one single point, not everywhere.
 
  • #16
alt said:
OK, but when the balloon was uninflated all the dots were at one single point, not everywhere.

The single point was equal to everywhere, everywhere was the single point...
 
  • #17
alt said:
OK, but when the balloon was uninflated all the dots were at one single point, not everywhere.

What you're missing is that the balloon/point/universe was not a point in space; it was a point that was all space. There was no space outside that point.

As DLuckyE says, that point is what constitutes "everywhere".
 
  • #18
DaveC426913 said:
What you're missing is that the balloon/point/universe was not a point in space; it was a point that was all space. There was no space outside that point.

As DLuckyE says, that point is what constitutes "everywhere".

From ..
http://www.thefreedictionary.com/

I think the agreed consise definition of singularity is;

Astrophysics; A point in space-time at which gravitational forces cause matter to have infinite density and infinitesimal volume, and space and time to become infinitely distorted.

It is difficult to believe or to even understand the notion that 'all there is' was contained in zero volume. Very difficult.

As Chronos said in ..
https://www.physicsforums.com/showpost.php?p=2849594&postcount=4

Plenty of work is in progress to remove the big bang 'singularity'. It is highly theoretical and speculative - largely because we have little or no clue haw to obtain the necessary observational evidence. We are fairly certain singularities are illogical, but, lack the math/evidence to dismiss them with any confidence. The nature of the universe remains quite mysterious.

As a layman (or less), I can certainly go no further than this.

But I sometimes entertain wild notions ..

"OK, assume it was initially a singularity - could it be that it still is, and that we exist still inside it, and are even smaller than that singularity ? After all, to call the universe 13.7bly wide (for our purposes) or to call us, say, 13.7b times smaller than the initial singularity, might just be the same thing"

But don't take me seriously - I'm probably being silly, seeing as I can't go in any other direction with it.
 
  • #19
jumpjack said:
The two sentences do not match!

Indeed, all dots on the surface were previously all in a single point: the centre of balloon VOLUME.

So, where is this point in the Universe? Can we determine it? How?

Or maybe the balloon surface (2d) represents our 3d universe?!?

Could we determine the "centre position" if it was in the 4th (?) dimension?

Can Flatland inhabitants determine position of objects in the 3d space surrounding them?

With respect to the surface of the balloon no location on the surface is the center of expansion

At time 0, the balloon was a point. As time progresses from then, it expanded into what we see now. The time/space location of point at time 0 only exist in the past and not in the present "balloon surface"
 
  • #20
alt said:
It is difficult to believe or to even understand the notion that 'all there is' was contained in zero volume. Very difficult.

True. Though we have rolled back the film to a very small fraction of a second after the BB, when it was still smaller than an atom.

I think I'll retroactively loosen the use of the term "point" - whether it is actually a single point or whether it was just a small volume - changes nothing in the scenario being discussed.
 
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  • #21
The fact that the theory has a singularity at the "starting time" doesn't mean that there actually was a physical singularity at that time. It's far more likely that the theory simply fails to describe what really happened when we get too close to the "starting time."

When or if we make observations that give us information about conditions before the earliest time that we can currently "observe," and they disagree with current theory, we'll simply have to revise the theory. In the meantime we work with what we have.
 
  • #22
jtbell said:
The fact that the theory has a singularity at the "starting time" doesn't mean that there actually was a physical singularity at that time. It's far more likely that the theory simply fails to describe what really happened when we get too close to the "starting time."
Yeah, this is what I am beginning to understand is the correct interpretation of the word.

Singularity doesn't identify an event or object, it simply identifies the boundary of our model - our knowledge of the event/object, beyond which it breaks down.

As with the BB, so it is with BHs (black holes).
 
  • #23
DaveC426913 said:
True. Though we have rolled back the film to a very small fraction of a second after the BB, when it was still smaller than an atom.

OK - even that though, is hard to accept. 'All that there is' was contained in something smaller than an atom .. there's something very wrong here, and I speculate that in my lifetime and yours, it will be shown as such.

I think I'll retroactively loosen the use of the term "point" - whether it is actually a single point or whether it was just a small volume - changes nothing in the scenario being discussed.

Zero volume, however, can be as different to small volume, as nothing is to everything.

I like your retroactivity, BTW :-)
 
  • #24
jtbell said:
The fact that the theory has a singularity at the "starting time" doesn't mean that there actually was a physical singularity at that time. It's far more likely that the theory simply fails to describe what really happened when we get too close to the "starting time."

That makes sense.



When or if we make observations that give us information about conditions before the earliest time that we can currently "observe," and they disagree with current theory, we'll simply have to revise the theory. In the meantime we work with what we have.

I can respect that too. Thanks !

(without ANY disrespect implied to any other posters)
 
  • #25
alt said:
'All that there is' was contained in something smaller than an atom .. there's something very wrong here

The only difficulty with the idea is that it goes against the concept of 'solid' objects - but we've already realized that's an illusion anyway.
The atomic theory dealt it a massive blow, quantum mechanics killed it stone dead.
 
  • #26
alt said:
OK - even that though, is hard to accept. 'All that there is' was contained in something smaller than an atom .. there's something very wrong here,

Let's be clear: none of that was matter. None of it was comprised of any substance that actually takes up room. Matter did not precipitate out until the universe was much much cooler.

Instead of looking at it as "full of stuff", think about this: How bright can a room get - how much light can you pack into a room - before it is "physically too full" of light?
 
  • #27
DaveC426913 said:
Let's be clear: none of that was matter. None of it was comprised of any substance that actually takes up room. Matter did not precipitate out until the universe was much much cooler.

Instead of looking at it as "full of stuff", think about this: How bright can a room get - how much light can you pack into a room - before it is "physically too full" of light?

Hi Dave;

Your 'light / room' analogy is very instructive and makes the point clearer to me. Thanks.

Your first paragraph "None of it .."

What is (or was) 'it' ? Mainly photons / electrons ? If so, mainly light precipitated into matter ?

Also, I'm still wondering about the singularity issue, which is what I jumped in about in the first place. Up till recently at least, singularity was thought of as a zero dimension / infinitesimal volume point, wasn't it ? That's what I was, and continue to have problem with.
 
  • #28
AJ Bentley said:
The only difficulty with the idea is that it goes against the concept of 'solid' objects - but we've already realized that's an illusion anyway.

If the physical world follows some rules which are essentially mathematical, then solid objects cannot be an illusion. If everything is an illusion, then we can accuse Newton and Einstein of creating illusions out of illusions. In that case, we would rather search for a metaphysical answer.
 
  • #29
alt said:
What is (or was) 'it' ? Mainly photons / electrons ? If so, mainly light precipitated into matter ?

It was too hot for electrons (another form of matter).

It is all energy (I think it was photons, but I'm not sure).
 
  • #30
finiter said:
If the physical world follows some rules which are essentially mathematical, then solid objects cannot be an illusion. If everything is an illusion, then we can accuse Newton and Einstein of creating illusions out of illusions. In that case, we would rather search for a metaphysical answer.

The objects are not an illusion, their solidity is what is illusory.

First we discovered that heretofore "solid" atoms are almost entirely empty space, then we discovered that protons and electrons are not solid either, but are comprised of quarks. Are quarks solid? As we look deeper and deeper, the components become more and more like energy fields than any "real" form of soild substance.
 
  • #31
shomas said:
With respect to the surface of the balloon no location on the surface is the center of expansion
Explosion center is of course not on the surface: it's in the space where the baloon is. Passing from balloon to Earth surface...: on Earth surface we behave as if it was a 2d surface, measuring distances along the sphere. Butit is not a 2d surface, it's a 3d spherical surface, which has a center.

At time 0, the balloon was a point. As time progresses from then, it expanded into what we see now. The time/space location of point at time 0 only exist in the past and not in the present "balloon surface"
Eaxactly: it is "in the past of balloon surface". As time is what allows Flatlanders to "see" 3rd dimension, maybe time is also what could allow us to see where balloon center was in the 4th dimension (I don't think time is a dimension); but I can't (yet :wink:) imagine how.
 
  • #32
DaveC426913 said:
What you're missing is that the balloon/point/universe was not a point in space; it was a point that was all space. There was no space outside that point.
Who says that?
Wasn't that just a huge amount of matter concentrated in a single point in the space? Matter did not exist, space did! Empty space!

Or not? :confused:

Can space exist without time?
 
  • #33
baloon (in that analogy) is not IN SPACE, it is in SPACETIME.
so big bang is point in SPACETIME (such points are called EVENTS), not IN SPACE.

The exact direction to the Big Bang is always "go directly to the past"
Dont take this analogy too literally.
 
  • #34
alt said:
OK - even that though, is hard to accept. 'All that there is' was contained in something smaller than an atom ...

I think the latest things from M-theory (which is still just a theory, untested) say that the big bang was possibly collision between two universes, much like how the Moon was formed when the Earth collided with another planet, so all the matter in our universe has come from the other universes...
 
  • #35
DaveC426913 said:
As we look deeper and deeper, the components become more and more like energy fields than any "real" form of soild substance.

So, at the level of electrons it is either fields or particles; and below that it is just fields only. Can fields remain independent? Fields may be due to still smaller solid particles. If that is the actual situation, then there would be no illusions - physics should be dealing with realities and not illusions.

Light may be particles in motion, the nature of its motion creating a varying charge and the moving charge creating a varying magnetic field. I have been working on that idea for some time and have arrived at a possible model.

Philosophy and science moved apart due to the big bang in the domain of physics. Now it seems that there would be a big crunch bringing the two closer. Have Newton and Einstein gone wrong?
 
  • #36
finiter said:
I have been working on that idea for some time and have arrived at a possible model.
This is not the place to share it. Sorry.
finiter said:
physics should be dealing with realities and not illusions.
Physics is dealing with reality! Energy and fundamental forces are just as real is any type of matter.

You're getting mixed up about definitions and semantics.

Again, the only "illusion" here is to us lay-humans; our human-scale ideas of "solid" are just simplistic is all.
 
  • #37
DaveC426913 said:
Physics is dealing with reality!

Of course. What I doubt is that now a days physicists are wandering away from that.
Reality, to me, is the lay-human concept that mass, volume and time associated with matter should have real positive values greater than zero.
DaveC426913 said:
Again, the only "illusion" here is to us lay-humans; our human-scale ideas of "solid" are just simplistic is all.

May be. But,that means I can visualize a non-real, but very complex, model and put forth the above arguments in defence. Had not such a situation led to wrong concepts? That is what I doubt.
 
  • #38
finiter said:
Of course. What I doubt is that now a days physicists are wandering away from that.
They're not wandering away, they're following the evidence. At some point in our search, the nuts and bolts of the universe will be too small and/or too big for our feeble organic senses (starting with atoms).


finiter said:
Reality, to me, is the lay-human concept that mass, volume and time associated with matter should have real positive values greater than zero.
The universe is not obliged to conform to your idea of common sense.

finiter said:
May be. But,that means I can visualize a non-real, but very complex, model and put forth the above arguments in defence. Had not such a situation led to wrong concepts? That is what I doubt.
As long as your model accurately describes the evidence (i.e. via experimental verification), then it's not wrong.

So are you verifying your model experimentally? Is it modeling nature at least as well as the current model? Does it make predictions that the current model does not, and do those predictions then turn out to be accurate - more accurate than the current model?

The Scientific Method is not simply coming up with fanciful ideas and wishful thinking that those ideas are real.
 
  • #39
finiter said:
Of course. What I doubt is that now a days physicists are wandering away from that.
Reality, to me, is the lay-human concept that mass, volume and time associated with matter should have real positive values greater than zero.


May be. But,that means I can visualize a non-real, but very complex, model and put forth the above arguments in defence. Had not such a situation led to wrong concepts? That is what I doubt.

You are falling into the trap that the universe should make intuitive sense to you, and frankly from Relativity on, it doesn't. Such is life. The rest, DaveC has covered well.
 
  • #40
Everywhere and nowhere!

Our entire foundation is the cosmological principle, telling us that no point in the Universe is special. If there was a particular point where the "Bang" happened, that would clearly be a special point and violate the cosmological principle. Rather, space and time themselves were created at the instant of the Big Bang (unlike a conventional explosion where the material flies through pre-existing space). If we take any point in the present Universe and trace back its history, it would start out at the explosion point, and in that sense the Big Bang happened everywhere in space.
In another sense, the location of the Big Bang is nowhere, because space itself is evolving and expanding, and it has changed since the Big Bang took place. Imagine the Universe is an expanding sphere; at any instant "space" is the surface of the sphere, which is becoming bigger with time (again I'm thinking of a two-dimensional analogy to our real three-dimensional space). The place where the "Bang" happened is at the centre of the sphere, but that is no longer part of the space, the surface means we are unable to "point" to the place where the explosion is supposed to have happened. However, all the points in our current space were once at the centre of the sphere, when the Big Bang took place.
 
  • #41
nismaratwork said:
frankly from Relativity on, it doesn't.

I agrre with you. GTR is a turning point. But its is the best point from where one can start an alternate search. Either you may get trapped or you may come out with a new explanation, which avoids GTR, but endorses its right predictions.
 
  • #42
finiter said:
I agrre with you. GTR is a turning point. But its is the best point from where one can start an alternate search. Either you may get trapped or you may come out with a new explanation, which avoids GTR, but endorses its right predictions.

It is not a turning point any more than objects of differing masses falling at the same rate was a turning point in Galileo's time, or the Moon and the apple being influenced by the same force was a turning point in Newton's time.

This one is just new to you.
 
  • #43
finiter said:
I agrre with you. GTR is a turning point. But its is the best point from where one can start an alternate search. Either you may get trapped or you may come out with a new explanation, which avoids GTR, but endorses its right predictions.
Why?

If GR makes all the right predictions, how is it wrong?
 
  • #44
DaveC426913 said:
It is not a turning point any more than objects of differing masses falling at the same rate was a turning point in Galileo's time, or the Moon and the apple being influenced by the same force was a turning point in Newton's time.

This one is just new to you.

It's an impressive stepping stone, and one that leaves us with terribly narrow margins to falsify and confirm it with current tech (especially 50 years ago and on!). It's obviously a much better approximation of nature, and obviously still an approximation, but like you I don't see how this is a "turning point" or launching pad for fanciful notions. QM and GR need to merge, or be replaced, but for anything short of the extremes of the microcosm, or enormous masses in small volumes, GR and QM do well.

Finiter: Did you read the PF guidelines? This isn't a place to float your unpublished personal theories. There are places for that, but this isn't it, like it or not.
 
  • #45
nismaratwork said:
Finiter: Did you read the PF guidelines? This isn't a place to float your unpublished personal theories. There are places for that, but this isn't it, like it or not.

I don't know whether hinting a possibility is tantamount to floating unpublished personal theories. If it is, I will avoid.
 
  • #46
DaveC426913 said:
Why?

If GR makes all the right predictions, how is it wrong?

Quoting from 'nismaratwork': "It's an impressive stepping stone" "and obviously still an approximation". So is it not logical to search from there itself?.

Quoting again from 'nismaratwork': "QM and GR need to merge, or be replaced". If replaced, the right predictions of GR would be explained by the new theory in another way. Afterall, GR is still an approximation.
 
  • #47
finiter said:
I don't know whether hinting a possibility is tantamount to floating unpublished personal theories. If it is, I will avoid.

Hinting isn't, but who hints without wanting to go into more? Trust me, it's better to have DaveC, or me or another standard user give you a heads up, than it is to run afoul of forum moderation.

To your last post, yes, I did say all of that, and yes it does make sense to look for something else. HOWEVER... I don't think a replacement for GR alone makes sense, as the problems with GR lie in its unification with QM, and maybe the issue is JUST with QM then? For all we know, black holes (unlikely as it seems) really are infinitely dense, Unitarity smashing holes in the cosmos.

You're correct that any new theory has a slim margin to adhere to, in which GR has been experimentally ans observationally verified. Personally, I should point out that I believe that all theories are and will be approximations of nature; that's not really a scientific view, just a personal belief. Anyway, all of this is interesting, but it brings us back to my first paragraph of this post: without discussing your own theories, there's no way to get into the specifics, and by discussing your personal theories you break the rules here.
 
  • #48
nismaratwork said:
without discussing your own theories, there's no way to get into the specifics, and by discussing your personal theories you break the rules here.

I agree with your observation.

nismaratwork said:
I don't think a replacement for GR alone makes sense, as the problems with GR lie in its unification with QM, and maybe the issue is JUST with QM then?

May be. More probably, may be with both. I think Newton's law of gravity also predicts a singularity. Something wrong with the concept of gravity itself?
 
  • #49
jumpjack said:
The two sentences do not match!

Indeed, all dots on the surface were previously all in a single point: the centre of balloon VOLUME.

So, where is this point in the Universe? Can we determine it? How?

Or maybe the balloon surface (2d) represents our 3d universe?!?

Could we determine the "centre position" if it was in the 4th (?) dimension?

Can Flatland inhabitants determine position of objects in the 3d space surrounding them?

Consider the Universe as a 3-dimensional loop. What this means is that if I travel long enough in 1 direction I will eventually come back out from the opposite side. Where would the center be in such a model?
 
  • #50
How does Moebius fit in this thread?!?
 

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