Time and relativity (split from The Nature of Time)

[studiot]

58 minutes ago, Mordred said:

without gravity certainly however you can't really have something that changes if that something has no spatial dimension. Can any object or state exist without a spatial dimension of some form. Time isn't an entity unto itself, so under that in order to have time you must something that changes

Temperature of a point particle ?

 

With respect to yourself and Markus, I think the viewpoint is too restricted.

[Mordred]

26 minutes ago, Genady said:

Why not? Some kind akin oscillating neutrinos?

All particles have a range of field influence, Such as the Compton wavelength, harmonic oscillations etc. the point like characteristic is only one characteristic that defines a particle the wavelike characteristics do apply.

12 minutes ago, studiot said:

Temperature of a point particle ?

\[E_{kinetic}\propto T \]

the kinetic energy of the particle is proportional to its temperature contribution so it must have space to move correct me if I'm wrong lol

13 minutes ago, studiot said:

 

With respect to yourself and Markus, I think the viewpoint is too restricted.

how so ? 

Edited December 29, 2022 by Mordred

[Genady]

7 minutes ago, Mordred said:

wavelike characteristics do apply

Without space, wavelike characteristics wouldn't apply. Does it mean time wouldn't exist? Are the wavelike characteristics necessary for a change?

[Mordred]

well any waveform changes so obviously you need time. You must have a space to take any measurement or to simply have some quantity to change of what it is to change. If you have absolutely nothing that changes then you certainly cannot apply time. You can simply state time exists for anything that has change.

[Genady]

2 minutes ago, Mordred said:

If you have absolutely nothing that changes then you certainly cannot apply time. You can simply state time exists for anything that has change.

Right, we've established already that a change is necessary for time to make sense. I don't see yet that change requires space. If there can be change without space, then there can be time without space.

[Mordred]

6 minutes ago, Genady said:

Right, we've established already that a change is necessary for time to make sense. I don't see yet that change requires space. If there can be change without space, then there can be time without space.

You also require a space to measure

A definition I always apply to physical is any measurable property, quantity or state. 

edit I should add the caveat that a common QFT view is that measurable equates to real as per real vs virtual particles. Though its better described as field perturbations vs excitations. 

Edited December 29, 2022 by Mordred

[Genady]

1 minute ago, Mordred said:

You also require a space to measure

1. Do you mean, if it cannot be measured it cannot change? I disagree.

2. Regardless of the 1 above, couldn't a measuring particle be attached to the changing particle? I.e., without a space.

[Mordred]

8 minutes ago, Genady said:

1. Do you mean, if it cannot be measured it cannot change? I disagree.

2. Regardless of the 1 above, couldn't a measuring particle be attached to the changing particle? I.e., without a space.

No that's not what I'm stating I simply stated in order to measure something you require space. I did not state change requires measurement

8 minutes ago, Genady said:

 

2. Regardless of the 1 above, couldn't a measuring particle be attached to the changing particle? I.e., without a space.

how would you ? you would have an effective range of interaction between the two particles ?

The better question would be is how you can even have a particle without space for it to reside ? the point like characteristic however miniscule still resides in space.

Edited December 29, 2022 by Mordred

[Genady]

5 minutes ago, Mordred said:

I did not state change requires measurement

This is good enough to continue the analysis. The statement,

15 minutes ago, Mordred said:

You also require a space to measure

does not affect this point:

18 minutes ago, Genady said:

I don't see yet that change requires space. If there can be change without space, then there can be time without space.

 

[Mordred]

how do you have existence of any form without space?

[Genady]

1 minute ago, Mordred said:

how do you have existence of any form without space?

There are many things in physics that exist without us being able to visualize them. Or did I misunderstand the question?

[Mordred]

The question is more fundamental than that.

its literally how can anything physically exist without taking up space. Physics describe physical processes and quantities 

[Genady]

I don't know how, but it does not mean that it is impossible. E.g., A. Zee mentioned such possibility here (just an illustration that it is not obvious that it is impossible):

Quote

... heading back into the Big Bang merely causes  g_ij to vanish; the Bang created space but not time.

Zee, A.. Einstein Gravity in a Nutshell (p. 785). 2013. Princeton University Press.

 

[studiot]

1 hour ago, Mordred said:

the kinetic energy of the particle is proportional to its temperature contribution so it must have space to move correct me if I'm wrong lol

 

1 hour ago, Mordred said:

how do you have existence of any form without space?

 

59 minutes ago, Mordred said:

The question is more fundamental than that.

its literally how can anything physically exist without taking up space. Physics describe physical processes and quantities 

I agree that form is related to space.

However a space point (I should not really have said point particle.) is different from any other point in a space, by definition.

Fourier methods define temperature at any space point in say a heated bar.

Are you saying these are wrong ?

 

1 hour ago, Mordred said:

A definition I always apply to physical is any measurable property, quantity or state. 

There is a deiiference between definable and measurable.

 

1 hour ago, Mordred said:

how so ?

It's to do with the points no one seems to want to take up that I mentioned when I first entered this thread.

[Genady]

1 hour ago, Mordred said:

how can anything physically exist without taking up space

Sorry, it should've appeared in my previous post.

Edited December 29, 2022 by Genady

[Mordred]

5 minutes ago, studiot said:

 

 

I agree that form is related to space.

However a space point (I should not really have said point particle.) is different from any other point in a space, by definition.

Fourier methods define temperature at any space point in say a heated bar.

Are you saying these are wrong ?

 

There is a deiiference between definable and measurable.

 

It's to do with the points no one seems to want to take up that I mentioned when I first entered this thread.

No I'm not your still applying space via a point in space for temperature that literally equates to my statement on measurement doesn't it? even if you define a space its still involves space.

15 minutes ago, Genady said:

I don't know how, but it does not mean that it is impossible. E.g., A. Zee mentioned such possibility here (just an illustration that it is not obvious that it is impossible):

 

Interesting thought but I rather doubt the conclusion by A. Zee but would have to read the analysis myself to truly understanding where he is coming from.

[studiot]

35 minutes ago, Mordred said:

No I'm not your still applying space via a point in space for temperature that literally equates to my statement on measurement doesn't it? even if you define a space its still involves space.

I'm sorry I really have no idea what this means.

I am also trying to identify points where we agree and where we disagree.

I would be grateful if you would do the same.

 

Please answer these questions

Would the equations of electrostatics be any different if there was no time ?

Would the equations of mechanical staticsl be any different if there was no time ?

Would the equations of gravitostatics be any different if there was no time ?

Would the equations of standing waves be any different if there was no time ?

[Mordred]

Yes to all the above

 I really don't see where your coming from with this. You know as well as I do that temperature for example is part of the EM field  a field itself requires space.

 I really don't see a purpose arguing validity of any form of state that does not involve space. If that state changes you obviously require time. Even if it doesn't can apply duration to that state

Edited December 29, 2022 by Mordred

[studiot]

7 minutes ago, Mordred said:

Yes to all the above

Thank you.

Can I take it that we are agreed that there is a fundamental difference between time and space ?

And further that this is relevant to the 'block universe' model ?

Here is a proposal

The fixed block universe doesn't only violate causality, it make a total nonsense of it.

And since most of Physics is concerned with causality in one way or another, most of Physics with it.

 

Edited December 29, 2022 by studiot

[Mordred]

Well quite frankly I never liked any metaphysical interpretation but block has always been one I found lacking.

Yes there is a fundamental difference on time to space. 

 

[studiot]

It isn't really metaphysics, it follows directly from the setup of a fixed (note I say fixed as described by MigL) block universe.

It is easy to see in a fixed block how this can arise, using Omar Khayyam's scrolls, I mentioned earlier.

Suppose  a particular scroll was written showing event points  as coloured circles.

Suppose further that a bright young reader observes that a blue event circle always seems to follow from a green circle.

So the entire scroll is like the entire fixed block universe. It is all there from start to finish or end to end.

Our bright scholar deduces a 'physical law'  that the green event is the 'cause' of the blue one.

But of course it is just that the scroll was written that way. Of course it could have been written many other ways.

So there are alternative possible laws. Correlation does not imply causation etc.

 

O K had more sagacious words about the scroll and the block and time.

 

[Mordred]

2 hours ago, studiot said:

Correlation does not imply causation etc.

 

lol you have no idea how often I have stated this detail. 

[Markus Hanke]

13 hours ago, studiot said:

With respect to yourself and Markus, I think the viewpoint is too restricted.

I feel I need to quickly summarise here what my viewpoint actually is, because I think my main thoughts have somehow gotten lost amongst extraneous detail. What I am basically saying is that, if you take the “time” out of “spacetime”, you reduce the overall dimensionality of the universe to 3D+0 (all spatial dimensions). While this leaves the form of the Einstein equations unchanged, it nonetheless has important ramifications, because as we know from differential geometry, the Weyl tensor identically vanishes in anything less than 4D. This immediately precludes the existence of gravitational radiation. Furthermore, since the Einstein equations tell us that R=0 in vacuum, this implies that both the trace and the traceless part of the Riemann tensor vanish here, meaning you have no gravity whatsoever in vacuum. In the interior of mass-energy distributions, then, only the trace of the Riemann tensor is non-zero, so you have pure Ricci curvature here, which is quite different from the 4D case. 

So what I am saying is that taking time out of the equation absolutely does have ramifications for gravity.

Furthermore, without time, I do not see how one could recover local Lorentz invariance, which is crucial for quantum field theory. Also, in a purely 3D universe, particles would not posses the property of spin. And so on.

I haven’t really mentioned change in all this, my thoughts are mostly of a geometric nature here.

[DanMP]

On 12/28/2022 at 9:16 AM, Markus Hanke said:

GR and SR are models that describe aspects of the universe - as such they answer mostly only the how questions, but not the why ones, in the same manner as a map describes the topography of some territory without providing an explanation of the geological processes that gave rise to that territory. That doesn’t make the map any less useful, if you’re trying to find your way from A to B.

Yes, but sometimes you need to know/understand better the "territory". From a 2D map/representation of a mountain you don't know that maybe there is a tunnel there, between A and B. If you understand erosion and tectonic plates theory you can predict a future decrease/increase in height.

In the same way, when we'll understand dark matter and/or we'll learn new things, maybe we will be able to have a better understanding and to make (and test)  new predictions regarding relativity. We may even keep the GR "map" and only change the understanding.

By the way, I don't think that our future is "written". The spacetime map that includes the future may be needed/useful, but ... don't confuse the map with the territory/universe. 

 

[Lorentz Jr]

On 12/28/2022 at 1:16 AM, Markus Hanke said:

GR and SR are models that describe aspects of the universe - as such they answer mostly only the how questions, but not the why ones, in the same manner as a map describes the topography of some territory without providing an explanation of the geological processes that gave rise to that territory. That doesn’t make the map any less useful, if you’re trying to find your way from A to B.

Until there's an earthquake, and then all of a sudden, knowing the answers to those "why" questions becomes VERY useful. 😉