Modes of Time

[Alceste]

GR exists in the equations – and nowhere in those equations is there a modelling of curve spacetime. If I am wrong then kindly point this out to me.

And for the record, I strongly object to your claim that me and linwood are disagreeing in the manner you are insinuating.

I'm not insinuating anything, least of all a "manner".

 

[themadhair]

I don't know. The equations in physics are over my head. But this article isn't too bad: black-holes.org—Gravity and Warped Spacetime

I’ll be a little more pointed. General relativity is a mathematic construction. I have studied the equations of general relativity, focusing particularly on the Schwarzschild solution, and nowhere in that have I seen anything that would allow the claims regarding the curvature of spacetime. If it isn’t in the equations then, aside from a useful analogy for understand the effects, where is it?

 

[Magic Man]

"Infinately dense" is an impossibility in the physical universe of matter and energy that we know.
The "singularity" in the popular Big Bang model is an invention of an imaginative mind.

I'm curious. What is the extent of your experience that allows you to put forth an assertion like this? In other words, what do you know that physicists don't? You strike me as an armchair physicist, but for all I know, you could have your degree in the subject.

From what I understand light is comprised of nearly matterless particles travelling through space.

Not "nearly". They are matterless, hence their ability to travel the speed of light.

The commonly accepted scientific ideas of the origin of the universe seem nearly as imaginative as the story of Genesis to me.

Well, that's your opinion, but this sounds to me just like someone denying evolution.

 

[Magic Man]

I’ll be a little more pointed. General relativity is a mathematic construction. I have studied the equations of general relativity, focusing particularly on the Schwarzschild solution, and nowhere in that have I seen anything that would allow the claims regarding the curvature of spacetime. If it isn’t in the equations then, aside from a useful analogy for understand the effects, where is it?

I didn't realize curvature was or had to be in the GR theory. Why would it have to be in there for it to be the case?

 

[Phasmid]

I think spacetime was once described as a flat sheet of rubber. Imagine space and time being a large rubber sheet. When you add a mass to it e.g. a ball of metal, it stretches and warps the rubber. And so spacetime is altered... or maybe that's how gravity was explained. I get confused.

 

[linwood]

I'm curious. What is the extent of your experience that allows you to put forth an assertion like this? In other words, what do you know that physicists don't? You strike me as an armchair physicist, but for all I know, you could have your degree in the subject.

I am most definately an armchair physicist.

I don`t however need a degree to understand the definition of "infinitely dense" or to realise that the concept is an impossibility considering the physical universe we live within.
A thing cannot be materially "infinitely dense".
Perhaps the real physicists should try using language in a manner that is generally understood so as not to cause as much confusion as they have.

Not "nearly". They are matterless, hence their ability to travel the speed of light.

Indeed, and yet gravity still affects them
Interesting no?

Well, that's your opinion, but this sounds to me just like someone denying evolution.

Not my problem.
Evolution has more evidence supporting it empirically than I could peruse in a lifetime.
Evidence for the Big Bang consists of universal expansion and redshift.
Neither of which shines any light on the concept of this infinitesimal singularity.

Not really overly impressive.

Question:
Is the singularity as described by the popular Big Bang model even a possibility when considered alongside what we materially empirically know of the universe we live in?

Can something really materially be infinitely dense?

 

[linwood]

I think spacetime was once described as a flat sheet of rubber. Imagine space and time being a large rubber sheet. When you add a mass to it e.g. a ball of metal, it stretches and warps the rubber. And so spacetime is altered... or maybe that's how gravity was explained. I get confused.

No you`re correct, that is the most common way spacetime is shown as an example.

It is however woefully misleading.

 

[Magic Man]

I am most definately an armchair physicist.

I don`t however need a degree to understand the definition of "infinitely dense" or to realise that the concept is an impossibility considering the physical universe we live within.
A thing cannot be materially "infinitely dense".
Perhaps the real physicists should try using language in a manner that is generally understood so as not to cause as much confusion as they have.

Indeed, and yet gravity still affects them
Interesting no?

Interesting, yes. So?

Not my problem.
Evolution has more evidence supporting it empirically than I could peruse in a lifetime.
Evidence for the Big Bang consists of universal expansion and redshift.
Neither of which shines any light on the concept of this infinitesimal singularity.

Not really overly impressive.

Question:
Is the singularity as described by the popular Big Bang model even a possibility when considered alongside what we materially empirically know of the universe we live in?

Can something really materially be infinitely dense?

Yes, it can. This post confirms my opinion. You really are just like a creationist denying the ToE without understanding it. These comments are eerily similar to "a cat can't turn into a dog, and a dog can't turn into cat".

 

[Magic Man]

No your correct, that is the most common way spacetime is shown as an example.

It is however woefully misleading.

According to you, that is.

 

[Alceste]

Quick confession, I made up the phrase "infinitely dense" myself, just now to communicate a point - that if the density of matter slows the passage of time, and if all the current matter-energy in the universe originates from one single point in space and time (AKA "spacetime"), it is logically consistent that time itself also begins at this point. Don't blame the Big Bang theory for my choice of words - I'm just attempting to explain how / why the phrase "before the Big Bang" is meaningless in the context of the Big Bang theory.

But like evolution, most of modern physics rests on the conception of space and time as a single multidimensional phenomenon, which is bendy. If you can't get past the idea of "time" as a 4th dimension, you haven't got a hope of grasping the other 7 dimensions.

It might be useful, though, if we can't let go of the linear concept of time we use to describe how old we are, conceptualize how long ago something happened or get to work when our bosses expect us, to think of time as it is used in physics as a separate thing altogether. As was suggested in the OP. Personally, though, if it comes down to a choice I'll go with physics, since it comes closer to explaining certain phenomena I have experienced that strongly suggest consciousness does not travel on strict a temporal line from Start to Finish, and is not necessarily spacially constrained either. (In other words, either the physicists are onto something or I'm insane.)

 

[Mr Spinkles]

Nonsense.

This isn`t an example of the "curvature" of space.

This is an example of the effects of gravity on photons.

Calling this a "curvature" of space is disingenuous however common the practice is.

It gives the layman the wrong idea.

If the "wrong" idea is that space can have curvature then the layman has the same wrong idea as most physicists. It is not simply "the effects of gravity on photons" because the time and space coordinates are mixed up with each other in a non-trivial way that is not compatible with how we think of normal space.

 

[Mr Spinkles]

I agree with this. Outside of mathematical equations it doesn’t really make any sense to talk about the curvature of spacetime.

Well the alternative to curved spacetime is presumably non-curved spacetime, which is incompatible with a mountain of experimental facts.

 

[Alceste]

Question:
Is the singularity as described by the popular Big Bang model even a possibility when considered alongside what we materially empirically know of the universe we live in?

I think you need to be more specific about what you mean by "what we empirically know of the universe". Do you mean, for example, that the particles we consider to be "matter" break down into smaller and smaller particles until we end up with things that are both matter and energy, and also neither? And that in proportion to the size of these particles that make up "matter", there is more empty space between them than there is between the planets and the stars?

It seems to me that if you packed it all together - all the particles that appear to us as matter - with no space in between, who's to say it wouldn't fit on the head of a pin?

 

[logician]

I thought a singularity was undefined, i.e. nobody really knows what constitutes it, as all laws of physics break down.

 

[Mr Spinkles]

Gravity does not "slow time down".
Gravity affect the devices we use to measure time.
It slows them down.

Like length, mass, position, and any other physical quantity you can think of, time is *defined* by certain devices/methods we use to measure it and standards for comparing measurements. Lots of things can affect the devices we use to measure anything......merely approaching some pH meters will throw off the reading.....but only an actual change in the thing being measured (time, pH), by definition, will give a different measured result if the measurement is performed under controlled conditions, which are designed based on the definition of the physical quantity being measured.

"Infinately dense" is an impossibility in the physical universe of matter and energy that we know.

Someone should tell the electrons, before they get in trouble.

The "singularity" in the popular Big Bang model is an invention of an imaginative mind.

True but so was the heliocentric model.....but anyway you are right, no one knows about the singularity, it's one possibility within the big bang model. But I really don't think the singularity is logically or practically impossible, we just don't have all the evidence in.

I think you just don't like the concept of infinity, and I don't blame you, and I agree with you that many physicists do not do a great job of explaining things.

But look, let's assume you are right, nothing can be infinitely dense. We are still going to have to deal with "infinite" things sooner or later. So let's imagine we take a non-infinitely dense object....an object with some mass and some non-zero volume.....and break it into smaller and smaller pieces. What do we end up with? Quarks and leptons? Whatever the pieces are, they have mass, and therefore they must have some non-zero volume (otherwise they would be infinitely dense, which we assume is impossible). So then we must be able to break them into smaller pieces too, and those pieces must break into smaller pieces, and on and on. So what are objects made of, ultimately? Apparently, they are made of an infinite number of infinitely tiny pieces with infinitely-small masses. Now we have THREE infinite quantities where before (when we assumed some things can be infinitely dense) we only had one. Oh dear! Arguably we were better off thinking of the hydrogen atom as being composed of TWO (not infinite) pieces, each of which has a mass (again not infinite)....and of course we are just philosophizing here, we haven't even touched the experimental data yet....that's funny, I don't see an infinite number of lines in the spectrum of hydrogen I see a finite number with finite spacings....

You have the right intuition, I think, by not being overimpressed by the mysticism of "infinity" and "curved spacetime" etc. You're absolutely right, these are man-made concepts, don't be fooled into thinking they are divine law or obvious truth. But even though they are abused and misused by those with a more mystical outlook they actually are perfectly good ideas, on par with "negative numbers" and 3D space as far as the facts are concerned.

 

[Alceste]

I thought a singularity was undefined, i.e. nobody really knows what constitutes it, as all laws of physics break down.

Sure, but IMO that's another way of saying the same thing, since time is one of the laws of physics. The OP suggests that time is / would be / should be a constant and therefore unaffected by an event such as a singularity, so there must be a "before".

 

[themadhair]

Well the alternative to curved spacetime is presumably non-curved spacetime, which is incompatible with a mountain of experimental facts.

I really have to object to this.

The experiments completely verify GR and the associated equations that describe the motion of light and matter under gravity.

Now please tell me where the curvature of spacetime enters into the equations of GR. Show me specifically where this occurs because when I studied this I saw nothing of the sort. The experiments verify GR – and contrary to popular belief GR has nothing to do with the curvature of spacetime. The rubber sheet analogy is great for conveying the effects (such as gravity waves), but terrible at representing what the equations actually say.

 

[logician]

Sure, but IMO that's another way of saying the same thing, since time is one of the laws of physics. The OP suggests that time is / would be / should be a constant and therefore unaffected by an event such as a singularity, so there must be a "before".

I disagree, there is no "time" w/o matter and energy. Strictly speaking there is no such thing as "before " a singularity. There is no way to record that period, or know anything about its existence.

 

[TechTed]

We are assuming that our supposed "laws of physics" are infallible. But what if our laws of physics are truly flawed due to the frame of reference we are constrained by (i.e. time)?

 

[Alceste]

I disagree, there is no "time" w/o matter and energy. Strictly speaking there is no such thing as "before " a singularity. There is no way to record that period, or know anything about its existence.

It's not what I'm saying, it's what the OP is saying. I disagree with it, and agree with you. So you agree with me. So there.