Relativity Explained Via Movement, Not Time

[my_wan]

Time is mysterious, but not artificial. It was Einstein's insight that length and time are bound inextricably in a cosmic ying-yang: specifically the L/t 'c', and that that value is a constant, either by measure, or by axiom.

length and time both are relative to this fixed value, still a very counterintuitive notion.

Time is only intrinsic to the degree that the sequence of events at a given point cannot involve the exact same event happening both before and after a reference event. Yet it becomes undefined relative to a separable point, hence both really simultaneous and really not simultaneous at the same time if time is given an independent status. Hence a violation of the principle of contradiction. Same thing happens when consider you how long now is relative to another observer. Two observers at 86% C are correct in saying that their now is twice as big as the others now.

If I claimed to have a light switch that stopped time in the Universe for a day, what would be the physical consequence if the claim was true? Zilch, nothing. It would have no empirical consequence whatsoever. Not even the day it was supposed to be turned off is real, since there is no events to define a day. How the information defined in a physical event set can vary in relation to one another to allow relativistic time dilation is trivial to outline. How such time dilation can somehow manipulate time defined as an independent variable seems to require a magic wand. Do you need an outline of a mechanistic analogy of the relation between space and time (not a claim of how it 'really' is)?

 

[ZapperZ]

This is all getting very confusing very quickly...regarding defining movement without an implicit involvement of time however, how about this: when my car has traveled X meters, i measure the distance traveled by a ray of light which was emitted as the car started to move. My car would then have traveled an equivalent Y meters of light. This is how I would think of doing it since light is my absolute displacement reference.

IH

That light would have traveled a distance in a particle time! It doesn't do that instantaneously! There is a time component here!

Zz.

 

[my_wan]

Pervect pretty much nailed it. The second notion of time (not proper time) in my opinion is merely the consequence of requirement to impose causal constraints on the order of such events. Hence it is a bookkeeping or symmetry that appears sort of like a background time. But is is just a causal constraint, not some absolute that runs independently from the proper time.

 

[danR]

Time is only intrinsic to the degree that the sequence of events at a given point cannot involve the exact same event happening both before and after a reference event. ...

If I claimed to have a light switch that stopped time in the Universe for a day, what would be the physical consequence if the claim was true? Zilch, nothing. It would have no empirical consequence whatsoever. ...Do you need an outline of a mechanistic analogy of the relation between space and time (not a claim of how it 'really' is)?

The way you use time-markers tells me that 'time' is a very real psychological/linguistic entity. The way physicists use 'time' likewise indicates they regard it as not only real, but in the formalism of 4-space description, entirely interchangeable with 'space'. And Einstein necessarily needed time in his analysis of simultaneity: things either happen at the same 'time', or they do not. 'Events' are informally time entities, not space or movement entities. One could almost consider an 'event' a motionless scalar thing.

 

[danR]

Pervect pretty much nailed it. The second notion of time (not proper time) in my opinion is merely the consequence of requirement to impose causal constraints on the order of such events. Hence it is a bookkeeping or symmetry that appears sort of like a background time. But is is just a causal constraint, not some absolute that runs independently from the proper time.

The thing is the thesis of this post: Relativity explained via Movement, not "Time". In fact, we could re-write the title:

'Relativity Explained by L/t, not "t".'

Well enough. I don't think that's too far from what Einstein said, the L/t in question being c, which is a constant in all observers' frames of reference. Sorta QED, no?

 

[atyy]

OK, let's try to see if some version of Hassan's proposal can hold. How about "time requires movement, but movement does not require time"?

Let me define movement as change dy/dx. dy/dx does not require time, since x, especially if x is 3D Euclidean space in Newtonian physics, doesn't seem to be necessarily time.

However, time requires dy/dx to be operationally defined, in some special cases where x = "time".

In this sense movement is primary, but time is not.

 

[Dale]

I believe that explanations of physical phenomenon -including relativity- would be so much easier using *movement* instead...

IH

How would you explain relativity using movement instead of time? In particular, how would you make the quantitative experimental predictions of relativity without time?

 

[my_wan]

The thing is the thesis of this post: Relativity explained via Movement, not "Time". In fact, we could re-write the title:

'Relativity Explained by L/t, not "t".'

Well enough. I don't think that's too far from what Einstein said, the L/t in question being c, which is a constant in all observers' frames of reference. Sorta QED, no?

There it is. A lot of OPs are started with a sliver of recognition followed by alphabet soup.

 

[danR]

Originally Posted by danR
The thing is the thesis of this post: Relativity explained via Movement, not "Time". In fact, we could re-write the title:

'Relativity Explained by L/t, not "t".'

Well enough. I don't think that's too far from what Einstein said, the L/t in question being c, which is a constant in all observers' frames of reference. Sorta QED, no?

There it is. A lot of OPs are started with a sliver of recognition followed by alphabet soup.

Let me clean it up a bit then:

The OP could be titled:

'Relativity Explained by Length/time, not time.'

For Einstein the Length/time in question being distance traveled by light/time, which is a constant in all frames of reference. So we are right back stuck with time, and Einstein and everyone still using time are actually still right to do so, Which was the thing to be demonstrated (by way of rebuttal).

 

[danR]

OK, let's try to see if some version of Hassan's proposal can hold. How about "time requires movement, but movement does not require time"?

Let me define movement as change dy/dx. dy/dx does not require time, since x, especially if x is 3D Euclidean space in Newtonian physics, doesn't seem to be necessarily time.

However, time requires dy/dx to be operationally defined, in some special cases where x = "time".

In this sense movement is primary, but time is not.

Only by treating time as a spatial axis. This seems akin to a Minkowski manifold.

But now there is no movement!

 

[Islam Hassan]

Let me formulate the subject a little differently then: does time exist in the sense of some immaterial yet physically effective 'ether' flowing through space? To my (rather confused) mind if it is immaterial in the sense that it is not observable *in itself*, it does not exist per se but is a practical concept we evolved in order to facilitate communication.

IH

 

[ZapperZ]

Let me formulate the subject a little differently then: does time exist in the sense of some immaterial yet physically effective 'ether' flowing through space? To my (rather confused) mind if it is immaterial in the sense that it is not observable *in itself*, it does not exist per se but is a practical concept we evolved in order to facilitate communication.

IH

This is a very tired topic because it has been discussed ad nauseum in this forum.

It is also quite confusing because you are asking for whether time, which can be measured quantitatively, can be defined using some esoteric, undefined quality ("immaterial yet phyically effective ether flowing through space"). That's like asking how physics can be defined using metaphysics! All of this is ignoring the fact that space itself can't be decoupled and separately measured without time!

Considering that there are numerous phenomena that are characterized by their broken time reversal symmetry, from that point of view, it is awfully silly to ask if time exists.

Zz.

 

[dx]

Independent 'existence' of space, time as well as matter is charactertic of Newtonian physics, i.e. we imagine a 'space' which is 'unaccelerated', and point particles (which in principle are imagined to constitute material objects) moving in this space. Thus we ascribe physical reality to space as well as to its state of motion. This is necessary because the idea of acceleration appears in Newton's law of motion. The same applies to time, which likewise enters into the concept of acceleration. So to summarize, in Newtonian physics 'physical reality' consists of space, time and material points moving with respect to space and time.

In the special theory of relativity, the four dimensional continuum of spacetime is no longer objectively resolvable into space and time, but this space (Minkowski space) occurs as an independent component in the representation of physical reality as carrier of matter and field.

In the general theory of relativity, the inertial frame loses its objective significance for the following reason. A frame accelerated with respect to an inertial frame can be thought of as an inertial frame together with a uniform gravitational field. Thus, space, as opposed to what fills space (represented by fields, and which depend on the coordinates) has no independent existence.

 

[atyy]

Let me formulate the subject a little differently then: does time exist in the sense of some immaterial yet physically effective 'ether' flowing through space? To my (rather confused) mind if it is immaterial in the sense that it is not observable *in itself*, it does not exist per se but is a practical concept we evolved in order to facilitate communication.

All quantities in physics are not observable "in themselves". For example, what is a charge? What is an electric field? There isn't a concept of charge independent of the field, and there isn't a concept of the field independent of the charge. Although there are formal solutions for fields without charges, we cannot observe these fields unless we have a charge.

All quantities in physics are concepts we evolved to consistently describe our observations, communicate with each other, and design devices that work the way we predict. But they are all (as far as we know) wrong at some level.

So a question about what "time" is, must take place within each of our limited but useful theories. Each theory will have its own definition of "time", which may overlap only partially with the notion of "time" in another one of our theories. Among these different notions of time are coordinate time and proper time of general relativity, cosmological time in the FRW solution of general relativity, thermodynamic time in the second law of thermodynamics, Newtonian coordinate time in Newtonian physics, psychological time in psychological experiments etc.

 

[Arens]

All quantities in physics are not observable "in themselves". For example, what is a charge? What is an electric field? There isn't a concept of charge independent of the field, and there isn't a concept of the field independent of the charge. Although there are formal solutions for fields without charges, we cannot observe these fields unless we have a charge.

Taken from wiki:
Electric charge is a physical property of matter which causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two negatively charged objects. the electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields.

Time is not matter, is a notion we use to determine movement of an object from A position to B , respective to another movement made from another object from C to D.

 

[DaveC426913]

Electric charge is a physical property of matter which causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two negatively charged objects. the electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields.

Well there you go atyy; you have been educated on what electric charge is.


Arens, seriously though. Quoting someone else's material - http://en.wikipedia.org/wiki/Electric_charge" - without credit is forbidden, and will result in infractions.

 

[Islam Hassan]

Ok thanks to everyone! Sorry I didn't realize that this topic had been discussed 'ad nauseam' before in PF: it was my very first post here. Will be more careful with my posts in the future.

At any rate, it seems that time is a considerably more intricate subject than I imagined; thank you again for your kind forebearance.

IH

 

[Selraybob]

I'm with you, Islam, except Time's not that complicated. Time's a count. Nothing more. I don't know why people make it so complicated. Aristotle started off okay, calling it a count, but he mucked it all up with the Now. And Einstein made it a fourth dimension and got everyone excited about space-time. But Time's a count. Even the NIST guys, who are supposedly measuring 'Proper Time' call Time a count right outside their clock. (Yep, I was there. It’s a big tube with mirrors all around. I even saw the new one, which wasn’t working. Really cool, the NIST guys and the clocks.) Here’s what the sign says:

“Time is defined as the accumulation of atomic seconds beginning 0000 Hours UT (Earth time) 1 January, 1958.”

That's why I can't go with ZapperZ:

"It is also quite confusing because you are asking for whether time, which can be measured quantitatively..."

Unless Time is defined as the changes in a cesium atom, or a count of changes, then Time can't be measured quantitatively. Every time you ask someone to measure Time, they find some counter that measures some change in something else. Clocks, sundials, whatever, they're all counters. And none of them works the same.

Even the NIST guys have to synchronize their clocks. They’ve got a few, and they only start the main one for a week every month so that they can set the others and then send out the official count all over the world. No clock counts the same all the time. It depends on where they are and the temperature and all sorts of things.

Atyy, though, got me thinking when he said that concepts in physics are wrong in some way. My problem is that whenever you look at a measure for just about anything, somewhere back there is little t. And little t is a count of some counter, which always changes, because how your counter works depends on where it is and what all the conditions are around it. Still, thinking’s good.

 

[Dale]

Time's a count.

A count of what?

 

[my_wan]

A count of what?

Events. Nobody can claim to absolutely know what a base event is or even if there is such a thing as a base event predicated on any particular ontology. Yet as long as there are events and systems are defined by sets of event, or sets of sets, and so on, then certain higher order events, linear relative to the base event sets of whatever ontology, can then be used as proxies to count said events. It works that way whether the system is purely mechanistic or it is merely relative to some abstraction of the laws of physics. Hence we have higher order measuring devices called clocks that count these linear events.

 

[Dale]

Events.

Well, it can't just be any events since some events are space-like separated, and even for timelike separated events I can think of examples where you wouldn't call the resulting count time.

 

[Selraybob]

It is events. When I say "Time is a count", it's really saying that since the first caveman looked at the moon and grunted out something like, "moon above again," and then made a mark on the wall, and then another the next time the moon was above, is counting up some events and calling that Time. It's the counting that comes first and the definition of Time that comes after. You can count moons moving around the Earth or suns appearing to move around the Earth or the ticks of a grandfather clock or water clock or atomic clock. But for comparing our lives against, and meeting someone down at the dock, it's good to have some sort of counter that's pretty regular. Doesn't matter what it is though.

 

[Dale]

It is events. ... Doesn't matter what it is though.

So counting ticks on my Geiger counter is time. If I put my Geiger counter in a lead box time stops. Is that really what you meant, because that is what you said.

Here is another set of events, the tick marks on my ruler when illuminated by a specific of light. The count is 12. So time is 12. Doesn't sound like your definition is related to the usual idea of time.

 

[my_wan]

Well, it can't just be any events since some events are space-like separated, and even for timelike separated events I can think of examples where you wouldn't call the resulting count time.

True, which is exactly what gets us into trouble with simultaneity, which I even recently embarrassed myself with. Yet even then the one constraint that allows us to define the relativity of simultaneity is the constraint that a 'local' event set sequence, E_i --> E_j --> E_k, cannot place any event in the set both before and after some other event in that set. That would amount to time travel.

Even if we assumed some 'toy' model of purely mechanistic events such as molecular collisions, if the background is undefined then local event sets must disagree on clock rates in many different circumstances.

 

[Dale]

True, which is exactly what gets us into trouble with simultaneity, which I even recently embarrassed myself with. Yet even then the one constraint that allows us to define the relativity of simultaneity is the constraint that a 'local' event set sequence, E_i --> E_j --> E_k, cannot place any event in the set both before and after some other event in that set. That would amount to time travel.

Even if we assumed some 'toy' model of purely mechanistic events such as molecular collisions, if the background is undefined then local event sets must disagree on clock rates in many different circumstances.

So then what sets of events can you count and call the resulting count "time"?

 

[my_wan]

So counting ticks on my Geiger counter is time. If I put my Geiger counter in a lead box time stops. Is that really what you meant, because that is what you said.

Here is another set of events, the tick marks on my ruler when illuminated by a specific of light. The count is 12. So time is 12. Doesn't sound like your definition is related to the usual idea of time.

If you insure that those ticks are scaled properly yes, which is why we can do carbon dating. Yet like the linear discontinuities you can get from any given pair of individual clicks we have the uncertainty principle telling us we are getting these small scale discontinuities at a fundamental level also. But averaged over they go away.

 

[Dale]

If you insure that those ticks are scaled properly yes

OK, so now we are no longer counting, but counting and scaling our count. That is fine, how do we determine the correct scaling factor for the count?

 

[my_wan]

OK, so now we are no longer counting, but counting and scaling our count. That is fine, how do we determine the correct scaling factor for the count?

Relative to any other local event set with has a reasonably stable linearity. The most fundamental of which is apparently a Planck unit of time, which is subject to the Uncertainty Principle. If you arbitrarily presume some mechanistic basis then what makes it linear does not mean linear in any absolute sense, it just means linear with respect to the mean local fundamental event sets defining the system. After all, relative to a clock under an acceleration of proper motion, linearity in terms of time alone loses relevance.

 

[my_wan]

The scaling is required simply so that our choice of event sets to count time is independent of the particular set of events used to do the counting.

 

[Dale]

Relative to any other local event set with has a reasonably stable linearity.

So the tick marks on a ruler is a good example since it is stable and very linear.