Where was the big bang singularity?

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    Big bang Singularity
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Discussion Overview

The discussion revolves around the concept of the big bang singularity and its implications for understanding the universe's expansion. Participants explore whether it is possible to identify a specific location for the singularity, the nature of expansion, and the limitations of analogies such as the balloon model. The conversation includes theoretical considerations and conceptual clarifications.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants argue that every particle in an explosion appears to be at the center of expansion, suggesting that the concept of a singularity's location is misleading.
  • Others propose the balloon analogy to illustrate that as the universe expands, no point can be identified as the center, as all points recede from each other uniformly.
  • A participant questions how a particle perceives its own motion and whether it can reference an external system.
  • There is a discussion about whether the balloon analogy accurately represents our 3D universe and if a center can exist in a higher dimension.
  • Some participants assert that the universe does not require a fourth dimension for mathematical descriptions of expansion.
  • One participant suggests that the observable universe's uniformity implies there is no center to the universe, as any center would create observable temperature variations in the cosmic microwave background (CMB).
  • Another participant argues that the term "where" is inappropriate when discussing the big bang, as it implies a spatial location that may not apply to the state of the universe before the big bang.
  • Some participants express confusion over the idea that a singularity could be described as "everywhere," leading to further clarification attempts using the balloon analogy.
  • There is a contention regarding the definition of singularity, with references to its implications in astrophysics.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of the big bang singularity and its implications for the universe's structure. There is no consensus on whether a specific location can be identified or how to interpret the concept of "everywhere" in relation to the singularity.

Contextual Notes

Participants highlight limitations in understanding the big bang and its implications, particularly regarding spatial concepts that may not apply prior to the big bang. The discussion reflects varying interpretations of analogies and definitions related to singularities.

  • #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 balloon 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.
 
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  • #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
balloon (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?!?
 
  • #51
jumpjack said:
How does Moebius fit in this thread?!?

The artist? He doesn't.
 
  • #52
jumpjack said:
How does Moebius fit in this thread?!?

As the actual shape of the universe is yet undecided, the space can even be visualized as a three dimensional moebius!
 
  • #53
finiter said:
As the actual shape of the universe is yet undecided, the space can even be visualized as a three dimensional moebius!

No, it can't.
 
  • #54
nismaratwork said:
No, it can't.

I would have said, 'a four dimensional moebius with three space dimensions and a time dimension'. In a two dimensional moebius, one dimension has borders while the other dimension has no borders. In a similar manner, the three space dimensions of the universe can have borders while the time dimension would be without borders.
 
  • #55
finiter said:
I would have said, 'a four dimensional moebius with three space dimensions and a time dimension'. In a two dimensional moebius, one dimension has borders while the other dimension has no borders. In a similar manner, the three space dimensions of the universe can have borders while the time dimension would be without borders.

The central feature of a moebius strip is the topology, which doesn't match that of the observed universe.
 
  • #56
typical guy said:
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.
...

Or perhaps, any signal originating beyond 13.7B LYs is going to be effectively below the Planck limit and therefore not detectable by any instrument. Now that would also throw a rather large brick at a lot of cosmological theory?

Thoughts?
 
  • #57
Cold Winter said:
Or perhaps, any signal originating beyond 13.7B LYs is going to be effectively below the Planck limit and therefore not detectable by any instrument. Now that would also throw a rather large brick at a lot of cosmological theory?

Thoughts?

I don't see how that would be the case, but if it were it would simply put a (presumably) temporary halt to our ability to search beyond 13.7B ly. The theory can still be sound as long as it doesn't make a wrong prediction, and given your formulation there could be no further predictions by any competing theories. According to your formulation, you just reach a "maximum resolution" for the 'image'.
 
  • #58
nismaratwork said:
I don't see how that would be the case, but if it were it would simply put a (presumably) temporary halt to our ability to search beyond 13.7B ly. The theory can still be sound as long as it doesn't make a wrong prediction, and given your formulation there could be no further predictions by any competing theories. According to your formulation, you just reach a "maximum resolution" for the 'image'.

Well, it "could" be, if the distance from an isotropic radiator is so far, that the energy level falls below quantum limits of resolution. We "solve" that problem by using a larger aperture. But just maybe there is no practical aperture once you get past a certain distance. Even gravitational lensing from another galaxy ( now there's a aperture for you :wink: ) simply might not be enough.
 
  • #59
Cold Winter said:
Well, it "could" be, if the distance from an isotropic radiator is so far, that the energy level falls below quantum limits of resolution. We "solve" that problem by using a larger aperture. But just maybe there is no practical aperture once you get past a certain distance. Even gravitational lensing from another galaxy ( now there's a aperture for you :wink: ) simply might not be enough.

Well, if string theory is correct that would be roughly the Planck length, but wouldn't that require a universe FAAAAAAAAR larger than the 13.7B ly we observe?
 

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