Where was the big bang singularity?

[DaveC426913]

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.

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.

 

[finiter]

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.

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.

 

[DaveC426913]

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).

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.

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.

 

[nismaratwork]

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.

 

[Ed Aboud]

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.

 

[finiter]

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.

 

[DaveC426913]

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.

 

[DaveC426913]

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?

 

[nismaratwork]

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.

 

[finiter]

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.

 

[finiter]

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.

 

[nismaratwork]

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.

 

[finiter]

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.

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?

 

[Flatland]

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?

 

[jumpjack]

How does Moebius fit in this thread?!?

 

[DaveC426913]

How does Moebius fit in this thread?!?

The artist? He doesn't.

 

[finiter]

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!

 

[nismaratwork]

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.

 

[finiter]

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.

 

[nismaratwork]

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.

 

[Cold Winter]

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?

 

[nismaratwork]

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'.

 

[Cold Winter]

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 ) simply might not be enough.

 

[nismaratwork]

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 ) 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?