If only two points exist does time flow?

[mistermack]

58 minutes ago, Strange said:

What is it then?

Wish I knew. But it can't be nothing. One thousand times nothing is nothing. A thousand metres of space time is a thousand times bigger than one metre. 

1 hour ago, Strange said:

Are you saying that metres and seconds are made of something? What are they made of? Wood, brass, sealing wax?

Quanta?

1 hour ago, Strange said:

I don't know what you base that on. But if you define a metric then that defines how distances are measured.

The way that light interacts with space time seems to be the most basic definition. Do you think that light can travel through nothing at all? 

[Strange]

2 hours ago, mistermack said:

But it can't be nothing.

Argument for on incredulity. Shrug. 

2 hours ago, mistermack said:

One thousand times nothing is nothing.

Are you confusing the concept of an empty universe with one that has no size?

2 hours ago, mistermack said:

A thousand metres of space time is a thousand times bigger than one metre. 

So you can measure things even in an empty universe. 

2 hours ago, mistermack said:

Quanta?

Of what?

2 hours ago, mistermack said:

The way that light interacts with space time seems to be the most basic definition. Do you think that light can travel through nothing at all? 

We are talking with of a model of an empty universe so there is no light. (But, yes, obviously light can travel through empty space)

[jajrussel]

9 hours ago, MigL said:

 

A dimension is not a 'place' that can contain points.
 

This statement threw me.

 

9 hours ago, MigL said:

 

A dimension is not a 'place' that can contain points.
Simply put, it is an axis of a co-ordinate system.
And his 'points' don't seem to correlate to space-time events.
I'm not sure what they are.

Then Strange called it, very succint. At which point I groaned out a weak, "how?" I kept thinking a millisecond is a point in time, a second is a point in time and time is a dimension, so "how, does this make sense?"

I don't know that much about coordinate systems, but I believe I understand the combined statement?

 

6 hours ago, mistermack said:

Yes. But empty space time isn't nothing. That's what I'm getting at really. The dimensions are dimensions of something, not nothing. 

In a universe of nothing, a metre is the same as a kilometre or a light year. In a universe of empty space time, a kilometre is still a thousand metres. Obviously, a universe of nothing is infinitely nothing, so you can say it doesn't exist. Infinitely nothing is as mysterious as a positive infinity. 

I believe I read that there are 17 different fields that make up space, hence the universe. I believe it was pretty much one field for every possible particle known to exist to include the gravitational field. If this is true, then space is not empty. Pherhaps someone else can clarify or correct this.

I can't quote you at this point because what I  want to quote is on page two and I'm afraid that if I go to page two I will lose what I have written. But, I believe your response to Stranges question was "Quanta".

My opinion is that Quanta is a good summation provided you allow for a certain amount of empty space for the sake of density.  I'm just saying what I think here for the sake of conversation. It might be that energy doesn't need space or a lack thereof to very in density. Once again I am hoping that someone will clarify or correct my thought if it is wrong.

Edited August 18, 2018 by jajrussel

[mistermack]

2 hours ago, Strange said:

We are talking with of a model of an empty universe so there is no light. (But, yes, obviously light can travel through empty space)

But I asked, "Do you think that light can travel through nothing at all? " So you are obviously equating empty space with nothing at all. I'm not going to pretend I know the score, but what I've been reading up to now doesn't match up with the idea that a vacuum is nothing. Even the curvature of space time doesn't suggest the curvature of nothing. If you can curve nothing that is. 

[Strange]

48 minutes ago, jajrussel said:

This statement threw me.

Think of a piece of graph paper: we normally plot the X axis along the bottom and the Y axis up the side.Then any position on the graph can be defined in terms of its X,Y coordinates. This is a two dimensional space with two spatial dimensions called X and Y.

You can think of a dimension as being a distance from the origin in a particular direction. The other key point about dimensions is that they have to be independent. So you can move a point in the X direction without affecting its Y position.

The simplest way of thinking of this is that the 3 dimensions of space are at right angles to one another, then changing a particles position in one dimension does not affect its position in the others.

Does that help?

And to go back to the confusion of the OP, there are an infinite number of points on our graph paper: there are an infinite number of positions along X and an infinite number of positions along Y, and therefore an infinite number of points (X,Y) across the surface of the paper. This is because the coordinates are continuous (they are specified as real numbers) so you can have positions 0, 1, 2 ... but also 1.5, 1.6, 1.601, 1.600001, etc.

But argo says that there are only two points. So how are we to interpret that? 

One easy way would be if there is only one dimension and it only has the positions 0 and 1 on it (i.e. it is not continuous and there are no positions between 0 and 1).

But argo also describes the points as 0,0 for example. So it seems to be a 2D system like our graph paper. In this case, we seem to have two dimensions each of which can only have the value 0 or 1. This means we actually have four possible points 0,0 0,1 1,0, 1,1 so this doesn't really meet the "only two points" criterion.

However, whatever is meant, there appears to be no time dimension (the "fourth" dimension in relativity) and so it is impossible to say anything about how time might relate to these "only two points.

So, in summary, the OPs question is, basically, meaningless. I think they are using the word "point" to mean something other than a location in a 2 dimensional space.

Edited August 18, 2018 by Strange

[studiot]

46 minutes ago, jajrussel said:

This statement threw me.

Several members are struggling with the meaning of the term 'dimension' at the moment.

It really depends what you are looking for?

[Strange]

Just now, mistermack said:

But I asked, "Do you think that light can travel through nothing at all? "

Light travels through the electromagnetic field. Which fills all of space.

But that has nothing to do with modelling space-time. You can, of course, add an electromagnetic, and other, fields to your model of space-time. But you don't have to. You can define, and use, a model universe which has nothing but the four space-time coordinates.

[studiot]

1 minute ago, Strange said:

Light travels through the electromagnetic field. Which fills all of space.

That was Newton's theory.

Relativity says something different, since there is no field till the light arrives.

Edited August 18, 2018 by studiot

[Strange]

2 minutes ago, studiot said:

That was Newton's theory.

I thought it was Maxwell's.

There is no electromagnetic field in Newton's theories, is there?

2 minutes ago, studiot said:

Relativity says something different.

Does relativity say anything about light?

But, certainly, the description of light in quantum field theory (which uses relativity) is different - light is described in terms of photons. But the field still fills all of space. (Doesn't it?)

Edited August 18, 2018 by Strange

[studiot]

7 minutes ago, Strange said:

I thought it was Maxwell's.

There is no electromagnetic field in Newton's theories, is there?

Does relativity say anything about light?

But, certainly, the description of light in quantum field theory (which uses relativity) is different - light is described in terms of photons. But the field still fills all of space. (Doesn't it?)

What a funny question.

I am referring to 'instantaneous action at a distance' (Newton not Maxwell) .

No there is no EM field in Newton, which is why I underlined the bit about the action filling all of space - ie instantaneous.

But most certainly there is no field until the light arrives, by both QFT and classical theory, otherwise we could have a reversal of cause and effect.

[Strange]

11 minutes ago, studiot said:

I am referring to 'instantaneous action at a distance' (Newton not Maxwell) .

I'm not sure what that has to do with anything I have said.

11 minutes ago, studiot said:

No there is no EM field in Newton

This is all entirely irrelevant to the topic of the thread. So let's drop it.

Edited August 18, 2018 by Strange

[studiot]

12 minutes ago, Strange said:

This is all entirely irrelevant to the topic of the thread. So let's drop it.

Why?

You stated that the electromagnetic field "fills all of space"

I don't agree and stated why not.

The EM field due to the light from our Sun did not exist in our (or any other) part of space before the Sun was formed.

 

[Strange]

7 minutes ago, studiot said:

Why?

Because the question (unclear as it is) is about "two points" and how they are related by special relativity. Nothing to do with light, EM fields, Newton, Maxwell, ...

The OP's points (excuse the pun) are confusing enough without adding more unnecessary entities.

Light only came up because of a sidetrack/hijack by mistermack. Maybe we should ask the mods to split all of that off to Trash.

Edited August 18, 2018 by Strange

[argo]

On 8/18/2018 at 12:56 AM, argo said:

Point A and B are physical points or a reference frame containing exactly one physical point each. Such a point would be a fundamental point of unknown composition as far as i know. Being of unknown origin i cant really say how many dimensions the point is that gives rise to a fundamental  physical point. I should have been clearer.

I did clarify and stated I wasn’t being clear enough. .

I think you have been referring to my use of the word point as one of the infinite points within a coordinate  system and I was meaning a fundamental component of an intrinsic object, introduced to represent a physical quanty in this frame.

I hope this corrects my silly mistakes now and gives some clarity to my question.

if i may change point to particle.

If only two fundermental particles exist, does time flow?

On 8/18/2018 at 5:08 PM, Strange said:

Don't be silly. It has nothing to do with "wanting" to answer. I am trying to understand what you are asking; and I am trying to answer based on what I can understand of your question.

ok then much appreciated.

On 8/18/2018 at 5:08 PM, Strange said:

On 8/18/2018 at 4:27 PM, argo said:

yes i am using time as a dimension containing exactly one fundamental point

Then it isn't a dimension.

It is not clear if you mean something non-standard by "dimension" or by "point".

A dimension consists of an infinite number of points: roughly it is a measurement of "distance" (which can be spatial or temporal). If there is only one point, then there is no measurement possible.

having made myself clear, - my point meaning a fundamental particle- two particles exist either at the same time or they exist at different times, in other words do the two particles exist simultaneously or not? is there a third choice?

 

On 8/18/2018 at 4:27 PM, argo said:

I am not sure how the established model of spacetime allows a point to exist at different times on one hand and together in reference frames at the same time on the other hand, in my version a point is exclusively at different times. This is the ONLY distinctions i am making between the two models,

in my version of spacetime the two particles must always exist at different times, in the established version of spacetime the two particles exist at different times but can also exist at the same time. Both versions allow for relativity but only the established version allows time to flow. Time flow needs the two particles to exist simultaneously so they can move through time together. Specifically in my version there is never one universal time. Can you explain how spacetime can do both?

 

 

 

[studiot]

18 minutes ago, argo said:

having made myself clear, - my point meaning a fundamental particle- two particles exist either at the same time or they exist at different times, in other words do the two particles exist simultaneously or not? is there a third choice?

Yes indeed there is at least one other choice.

One or both particles may give off radiation which extends to the othr particle.

Since there are only two (interacting) particles in your frame there is no observer in that frame.

So we must look to some other frame to observe the interaction and this immediately brings in Relativity of simultaneity.

[MigL]

I still don't see how relativity allows time to 'flow'.

It doesn't.
what you call 'flow', for a particle,  is more accurately viewed as a 'line', at an angle greater than the light cone ( that pesky SoL limitation ), extending through its lifetime.

[Strange]

14 minutes ago, argo said:

I think you have been referring to my use of the word point as one of the infinite points within a coordinate  system and I was meaning a fundamental component of an intrinsic object, introduced to represent a physical quanty in this frame.

I'm not sure what "a fundamental component of an intrinsic object" means. 

Maybe you mean a "test particle"?

Quote

In physical theories, a test particle is an idealized model of an object whose physical properties (usually mass, charge, or size) are assumed to be negligible except for the property being studied, which is considered to be insufficient to alter the behavior of the rest of the system. The concept of a test particle often simplifies problems, and can provide a good approximation for physical phenomena.

https://en.wikipedia.org/wiki/Test_particle

16 minutes ago, argo said:

if i may change point to particle.

That sounds like a "yes".

17 minutes ago, argo said:

If only two fundermental particles exist, does time flow?

Again, as time doesn't really "flow" (in SR) it is hard to answer this but lets try ...

Particles are represented as "world-lines"; i.e. a path through space time. If the particle is stationary then this will be a straight line parallel to the time dimension. If it is moving, then it will be a wiggly line that moves around in the spatial dimensions but still goes "forward" (ie "flows") through the time dimension. 

This is true for one particle, two particles or a million particles. 

22 minutes ago, argo said:

two particles exist either at the same time or they exist at different times, in other words do the two particles exist simultaneously or not? is there a third choice?

The concept of "existing at the same/different times" is not very clear.

All the atoms in my body, and the particles they are made up of, exist at the same time otherwise I would be like some strange character from Dr WHo; spread out through time and not really existing anywhere (or anywhen).

And if two particles (or people) are in relative motion they can still "exist" at the same time: I can talk to a friend wheile they are travelling on a high speed train. So speed does not mean we exist at different times. On the other hand, I can't talk to someone who was alive two centuries ago because they existed at a different time.

 

All of that may be obvious, irrelevant and silly. I only mention it to highlight that it is still not very clear what you are asking.

 

So let's go back to what SR actually says about two particles in relative motion:

• Each particle will see the other's ruler(1) shortened in the direction of movement.
• Each particle will see the other's clock(2) run slow than their own.
• Each will, potentially, have a different view of the ordering of external events (2)

That's about it. 

Note:

(1) These are conceptual rulers and clocks; but we need some way to make measurements otherwise we can't apply relativity.

(2) As there are only these two particles there can't be any actual events!

35 minutes ago, argo said:

Time flow needs the two particles to exist simultaneously so they can move through time together.

I'm not sure why. If we consider a universe where there was one short-lived particle (A) on Tuesday afternoon and another particle (B) on Friday morning then they don't exist at the same time but time still "flows" for them.

36 minutes ago, argo said:

Specifically in my version there is never one universal time.

And that's true in relativity as well. The time is observer dependent. Different observers will potentially see events happening at different rates and may even disagree about the order they occur in.

[argo]

20 hours ago, Strange said:

All the atoms in my body, and the particles they are made up of, exist at the same time otherwise I would be like some strange character from Dr WHo; spread out through time and not really existing anywhere (or anywhen).

I don't think it obvious, irrelevant or silly, i think it qualifies your true position, so i can deduce from this you think all the elementary particles in the universe exist at the same time. Is this not one universal time?

21 hours ago, Strange said:

21 hours ago, argo said:

Specifically in my version there is never one universal time.

And that's true in relativity as well

wiki-relativity of simultaneity

In physics, the relativity of simultaneity is the concept that distant simultaneity – whether two spatially separated events occur at the same time – is not absolute, but depends on the observer's reference frame.

I don't think the Dr Who character is that bad, i totally disagree he wouldn't be anywhere or anywhen, like all of us he would exist here and now, can you qualify yourself being anywhere or any when else?

 

[studiot]

29 minutes ago, argo said:

I don't think it obvious, irrelevant or silly, i think it qualifies your true position, so i can deduce from this you think all the elementary particles in the universe exist at the same time. Is this not one universal time?

Yes I think you have are asking a very good question, +1, but unfortunately also arguing from extremes thus clouding the issue.

 

Essentially you are observing (I think) that the curvature in GR in a given volume depends upon the matter particles present in that volume(as well as to a lesser extent those more remote).

Thus if a particle that exists in one spacetime frame but doesn't in another doesn't that imply that curvature and therefore relativistic effects eg gravity are frame dependant?

 

Please confirm my reading of your question or offer the correct one.

Edited August 20, 2018 by studiot

[Strange]

39 minutes ago, argo said:

I don't think it obvious, irrelevant or silly, i think it qualifies your true position, so i can deduce from this you think all the elementary particles in the universe exist at the same time. Is this not one universal time?

There is no one universal time. Time is observer dependent.

What I was trying to do (and failed, obviously) was to demonstrate that your phrase "two particles exist at the same time" is so vague as to be meaningless. Unless you can define what you mean more precisely, this isn't going to go anywhere.

41 minutes ago, argo said:

wiki-relativity of simultaneity

In physics, the relativity of simultaneity is the concept that distant simultaneity – whether two spatially separated events occur at the same time – is not absolute, but depends on the observer's reference frame.

1. That is what I have been telling you. So what was the point of quoting this?

2. Relativity of simultaneity is precisely (mathematically) defined. Your questions are so vague that they are impossible to answer properly.

3. When quoting a source please provide a reference (e.g. a link).

4. When quoting material, please do something to make it clear what is quoted (e.g. put it inside a quote box)

[argo]

17 hours ago, studiot said:

Yes I think you have are asking a very good question, +1, but unfortunately also arguing from extremes thus clouding the issue.

thanks, it is hard to show everything that is required without showing it all, without extremes. I will try to heed what your saying about from where i am arguing from but most of the time it's  reactionary and i have no choice.

18 hours ago, Strange said:

https://en.wikipedia.org/wiki/Relativity_of_simultaneity (editted link)

In physics, the relativity of simultaneity is the concept that distant simultaneity – whether two spatially separated events occur at the same time – is not absolute, but depends on the observer's reference frame.

whether- asking if two events occur at the same time or different times.

event- if at different times the event can only be a function of time, not timespace and modeled thusly.

is not absolute- is not known whether...

Unless you can rule out the Dr Who character relativity only asks whether

relativity doesnt rule out the Dr Who character, it asks whether. Introducing the observers reference frame

https://en.wikipedia.org/wiki/Frame_of_reference

In physics, a frame of reference (or reference frame) consists of an abstract coordinate system and the set of physical reference points that uniquely fix (locate and orient) the coordinate system and standardize measurements.

if every particle existed at a different time it would be an abstract coordinate system of here and now only and this is not the established spacetime model.

sorry have to go to work before i worked on quote box or checked this post thoroughly.

 

 

[jajrussel]

On 8/19/2018 at 10:00 AM, Strange said:

So let's go back to what SR actually says about two particles in relative motion:

• Each particle will see the other's ruler(1) shortened in the direction of movement.
• Each particle will see the other's clock(2) run slow than their own.
• Each will, potentially, have a different view of the ordering of external events (2)

That's about it. 

I have a question about bullet point two. How does that work? I thought the faster particle would have the apparent slower clock. Or is this an anti-paradoxal way of saying it. Each particle sees itself as standing still therefore the other particle will always appear to be moving faster, and the faster moving clock always appears to be keeping time more slowly?

I didn't think the mirror image position was generally accepted, otherwise where is the twin paradox?

Actually the more I read this, as in over and over the more confused I get.?

Actually it would help if I could keep my own thoughts in order. Paradox? What exactly is the paradox? The mirror image? I think?

Pherhaps my confusion is in what I am thinking you mean by relative motion?

Regardless, bullet point two, seems impossible without allowing the concept of mirror imaging?

Actually, bullet point one seems to be mirror imaging. And is an interesting thought in itself. Is this a geometrical reality. I understand that relativity presents things measuring longer or shorter due to their velocity in opposition to mine, but does the change in size occur from a direction?

I'm trying to keep up with the gist of the conversation if I'm a little slow I'm sorry. 

Hmm, I guess it would for the observer and the one effected. I realized that the direction of effect question I asked was kinda like a graviton question. Direction matters, the feet are effected first unless I'm falling head first.

This video contains the coordinate system presented by argo in the OP at about 9:27 on my device.

 

Edited August 21, 2018 by jajrussel
As usual a memory correction

[studiot]

4 hours ago, argo said:

thanks, it is hard to show everything that is required without showing it all, without extremes. I will try to heed what your saying about from where i am arguing from but most of the time it's  reactionary and i have no choice.

I think you have a choice.

So how about concentrating more on those who are simply trying to help rather than contradict, as oppose to the other way round?

Please let me know if I interpreted your idea correctly?

[Strange]

6 hours ago, jajrussel said:

have a question about bullet point two. How does that work? I thought the faster particle would have the apparent slower clock. Or is this an anti-paradoxal way of saying it. Each particle sees itself as standing still therefore the other particle will always appear to be moving faster, and the faster moving clock always appears to be keeping time more slowly?

Exactly.

6 hours ago, jajrussel said:

I didn't think the mirror image position was generally accepted, otherwise where is the twin paradox?

That is not a symmetrical case. One of the twins moves relative to the other one. We know this because he accelerates and decelerates. Acceleration is "absolute" - you can tell when you are accelerating because you will feel a force. 

(Note there are versions of the experiment where you eliminate the acceleration but the same principle of asymmetry between the twins applies; it is just more complicated to explain!)

6 hours ago, jajrussel said:

Paradox? What exactly is the paradox?

The "paradox" is: something happens that is counter-intuitive. There are no real paradoxes in physics. The various things that are called "paradoxes" only appear that way if you don't know the explanation. (A bit like magic tricks!)

 

[taeto]

1 hour ago, Strange said:

The various things that are called "paradoxes" only appear that way if you don't know the explanation. (A bit like magic tricks!)

Nice.