Is 'time' a measurable variable?

[Queso]

No one knows what they're talking about.

I KNOWWWWWWWWWWWWWWWWWW

[cwes99_03]

I would say that there is no "now".

If everything shared the same time...everything would be one single thing.

And if it did...nothing would exist.

 

 

Well, I don't quite think you understand your catesian coordinate system quite right. Each tick of the clock is another moment in time slipping by. Therefore as time moves on everything does occupy one time coordinate.

 

The problem being discussed in this thread is how to accurately say when something happened in two different places since two clocks separated by some space are in different frames of reference according to SR and GR, and therefore the clocks are almost certainly measuring time differently.

 

Therein lies the cunundrum. If two clocks never measure the passage of time in the same way, then what do we accept as the standard measure of time. A second in one frame of reference as measured by another is 1.0000000000000000011 seconds. Now over the length of a day this may seem insignificant, but as measurement techniques get more and more accurate, those last couple of sig figs do become important.

 

In times past (yes, I know there is something funny there) rules of measurement were different in different places. So a gold standard was set up for measuring masses, and objects were encased in vacuum chambers for measurement of lengths as standardization techniques. But then along comes relativity.

 

Now scientists believe that depending on the reference frame one is in, the length of an object may be contracted due to the velocity it is being measured at according to another system. Time also may be dialated. So how do we set up standards for length, time, mass, etc. as we enter a scientific world where 10^-20 of a meter, kg, or a second becomes greatly important.

 

Passage of time is still somewhat easily measured as light still traverses the vacuum at speed c regardless of what frame of reference we are in, but does it really? If I am sitting outside of a black hole, how fast do I measure the light to be traveling 100,000 km nearer the hole. A person 100,000km nearer the whole measures it to be traveling at c, but I myself also measure their clocks to be traveling slow. There is a fine toothed cunundrum there that does require more thought.

 

If this was your meaning Doc, then fine thinking and I shall think more deeply on this, though I am unwilling to say at this point that there isn't some answer in Einstein's GR or SR that doesn't explain this.

[Doctordick]

Math logic can be difficult :rolleyes:

When the concepts become "simple" it becomes difficult for the mind to grasp em.

Yes, that is particularly true when a new concept is introduced as misinterpretation is quite hard to avoid.

I can't say i understand everything you wrote but give me some time and maybe i can say something about the logic.

Well, how about we step through the logic one step at a time. At least then we can discover where your "understanding" deviates from my meaning. We may uncover a critical point where I have skipped something essential. I am afraid I have very strong suspicions that, without a little feed back, I will never be able to figure out where your interpretation of what I am saying deviates from the intention of my arguments. At least that is my experience from the past. :)

 

Looking to here from you -- Dick

[C1ay]

After thinking about this I tend to think that absolute time is immeasurable. Only relative time is measurable and then, only relative to the local reference frame or frames that can be synchronized with the local frame.

[cwes99_03]

So far as I can see, I'm inclined to agree with you, but then that throws major wrenches into the age of the universe question, right? So maybe there is something I'm missing.

[C1ay]

So far as I can see, I'm inclined to agree with you, but then that throws major wrenches into the age of the universe question, right? So maybe there is something I'm missing.

I'm not a believer in the age of the universe anyhow. I conceed that there may have been some kind of big bang event but I don't consider that evidence enough that it is responsible for any beginning of the universe.

[Doctordick]

After thinking about this I tend to think that absolute time is immeasurable. Only relative time is measurable and then, only relative to the local reference frame or frames that can be synchronized with the local frame.

I absolutely agree with you. People seem to misinterpret what I am saying. I never said I wanted to get rid of the concept of time. What I said is that I wanted to get rid of the concept that "time is what clocks measure". I want a clock to be defined as a mechanism which measures the change in tau between interactions along it's own path. That definition totally allows any local frame type reference so long as the difference between the frame of the clock and the frame of the observer can be ignored.

 

My definition of time, "the past is what you know, the future is what you don't know and the present is the change in your knowledge and 'time' is a mental parameter designed to give order to that change in information" is totally consistent with your experiences. I thus leave time as a very important mental concept allowing one to order their changes in knowledge. Certainly that is a valid concept so long as it applies to your personal experience and, for all events you do not actually experience, you have the freedom to insert them into that mental image you created, in any manner you wish (the intelligent thing to do is to insert them with a time parameter which makes sense in your mental image of reality). The important issue here is that what you know and what you think you know are quite different things and that issue should not be forgotten.

 

Since your interactions with the universe constitute a change in your knowledge of the universe, all interactions occur at the boundary between the past and the future. By saying time is only a measurable thing within the personal experiences of the entity, one is left to include the concept that time being the same (though it is not a measurable variable from a universal perspective) is required in order for interactions to take place. That was the fundamental meaning of time when it was first introduced (the concept of time was around a long time before clocks were invented).

 

Have fun -- Dick

[ldsoftwaresteve]

DoctorDick:

My definition of time, "the past is what you know, the future is what you don't know and the present is the change in your knowledge and 'time' is a mental parameter designed to give order to that change in information" is totally consistent with your experiences. I thus leave time as a very important mental concept allowing one to order their changes in knowledge. Certainly that is a valid concept so long as it applies to your personal experience and, for all events you do not actually experience, you have the freedom to insert them into that mental image you created, in any manner you wish (the intelligent thing to do is to insert them with a time parameter which makes sense in your mental image of reality). The important issue here is that what you know and what you think you know are quite different things and that issue should not be forgotten.

Hi DD. I love the above definition. I did read your stuff and I suppose you remember trying to get me to understand your meaning...But, the math was too hard for me. The jumps were too big or my blind spots were too large for me to see around. I do think that the problem you have getting others to understand your work is that our definitions are not as clear as yours are or perhaps not as true.

 

I like the idea of clocks not measuring time because time is probably just an effect and it wouldn't surprise me if it didn't exist as a separate entity. Only a consciousness is aware of change and the idea of time is totally a mental construct. I guess then that time might not be a causative agent.

 

Just a silly observation; if our memories were so powerful that we could not differentiate past perceptions from current ones, we might not even be able to construct the concept of time.

[InfiniteNow]

All everything's share the same time... Now.

 

Not unless they're at the same place. :estrange:

 

 

Subtle, but deep. I am going to look up the definition of an event again. :confused:

[Erasmus00]

II want a clock to be defined as a mechanism which measures the change in tau between interactions along it's own path. That definition totally allows any local frame type reference so long as the difference between the frame of the clock and the frame of the observer can be ignored.

 

This is what is done in special relativity, and is how physics thinks of clocks. Your "redefining" was done with Einstein, and the concept of spacetime is based around it. Clocks measure "proper time" which is just there local rest frame, i.e. the "tau" between events.

-Will

[cwes99_03]

Remind me again, but tau is just the inverse of a frequency, or time between event one and event two, right?

 

Isn't time simply a stringing together of events 1,2,3,4, etc?

 

Your redefinition does nothing to change anyone's concept of time. Saying that a clock measures the time between events not proper time is like me saying a light meter measures how dark it is in a room not how bright it is. The time between events in a reference frame is proper time, else there is no such thing as proper time, but no surprise there, SR and GR already state to us that a proper time for all reference frames does not exist, but that if these reference frames share a light source that each can interact with each other and dilation of time can be known. Thus light (radiation) is the key identifying factor of time, and without it we cannot measure it.

[Doctordick]

This is what is done in special relativity, and is how physics thinks of clocks. Your "redefining" was done with Einstein, and the concept of spacetime is based around it. Clocks measure "proper time" which is just there local rest frame, i.e. the "tau" between events.

Not exactly what I did. My argument with the academy is that Einstein's space-time concept confuses the issue of exactly what clocks measure. My position is that there exists no mechanical device capable of measuring time (where time is a parameter of motion of complex constructs). I hold that clocks measure changes in tau which is another real axis orthogonal to the accepted space axes x, y and z.

 

In my perspective, this tau direction is not apparent to us for the very simple reason that everything we deal with on a day to day basis is in a momentum quantized state in the tau direction thus the uncertainty in tau is infinite. Momentum in the tau direction is what is ordinarily called mass. If one works out the kinematics of such a picture, one obtains exactly the same results obtained through relativity. The only difference is that, in my picture, the entire thing is consistent with quantum mechanics from the word go. By the way, you should be aware of the fact that there are major difficulties with the problem of handling quantum mechanics in Einstein's theory of GR.

 

Just as an aside, one of the great supporting pillars of Einstein's GR is the fact that it explains gravity as a consequence of geometry. Newton's F=ma is valid only in an inertial frame and, if the frame of reference is not inertial, fictitious forces arise as a consequence of that fact (they used to be called pseudo force but apparently that terminology has been dropped since I was a student). Coriolis and centrifugal forces are common examples of such fictitious forces. One outstanding characteristic of these fictitious forces is that the force is always directly proportional to mass (that is because the the acceleration is actually not due to a real force at all but is a consequence of the acceleration of the frame of reference).

 

Since the gravitational force is directly proportional to mass, scientists searched very hard for a geometry which would yield gravity as such a fictitious force. They pretty well failed. According to Adler, Bazin and Schiffer (see the Introduction to General Relativity, McGraw-Hill Co., New York, 1965, p. 7.) "Einstein proved that "a reduction of gravitational theory to geodesic motion in an appropriate geometry could be carried out only in the four-dimensional space-time continuum of [Einstein's] relativity theory". If that statement is true then he certainly has strong support that his picture is worth the effort; but, the real question is: is it true? I say it is not! A careful examination of the kinematics of my perspective makes it quite clear that my geometry is in fact readily amenable to the problem of reducing gravitational theory to geodesic motion and I personally have done exactly that.

 

Hope I haven't overwhelmed you! I think things would be much more streight forward if we were to go to a line by line analysis of "A Universal Analytical Model of Explanation Itself".

 

 

Have fun -- Dick

[Buffy]

My position is that there exists no mechanical device capable of measuring time.

;)

Sooooo, if its not *possible* to measure tau's relationship to "real time", what relevance can it have to any scientific analysis? Its fine to discuss, but if you can't measure it, then by definition it does not provide any sort of falsifying data contradicting Uncle Albert.

 

Do you want to clarify how we'd ever confirm the existence or even relevance of "real time"?

 

Inquiringly,

Buffy

[InfiniteNow]

Not exactly what I did. My argument with the academy is that Einstein's space-time concept confuses the issue of exactly what clocks measure.

DD,

 

Since you are always so aware of being clear and ensuring proper definitions, I wanted to remind you that clocks do not measure anything. It is the observer of the clock making the measurement.

 

 

Cheers. ;)

[cwes99_03]

Now come on Infy, let's not get too technical, computers measure things all the time, and a clock is nothing more than an ultra old computational device.

 

DD, please read my post above about Tau and let me know if I'm wrong or right.

[Erasmus00]

Not exactly what I did. My argument with the academy is that Einstein's space-time concept confuses the issue of exactly what clocks measure.[...] I hold that clocks measure changes in tau which is another real axis orthogonal to the accepted space axes x, y and z.

 

In Einstein's theory, clocks measure proper time, which you are calling tau. You seem to say that you have an argument with the academy but at the same time, you seem to agree with them.

 

The reason that Einstein's metric is setup the way it is, with "local time" entering in as a coordinate is simply because it allows vector analysis. Proper time is coordinate invariant, but local time is not. In physics, it is always easier to work with invariants. That clocks measure proper time should be obvious, the time elapsed on a clock should obviously be coordinate invariant.

 

In my perspective, this tau direction is not apparent to us for the very simple reason that everything we deal with on a day to day basis is in a momentum quantized state in the tau direction thus the uncertainty in tau is infinite. Momentum in the tau direction is what is ordinarily called mass.

 

What you are speaking of is the standard energy/time uncertainty in quantum mechanics. Energy is canonically conjugate to time, just as momentum is conjugate to position. I point out that the uncertainty in tau is not, in fact, infinite, as an object's mass is never completely certain.

 

The only difference is that, in my picture, the entire thing is consistent with quantum mechanics from the word go. By the way, you should be aware of the fact that there are major difficulties with the problem of handling quantum mechanics in Einstein's theory of GR.

 

Special relativiy is completely consistent with quantum mechanics, and is the backbone of quantum field theory. I point out that you have not advanced any theory of gravity in the above, so you haven't in any way improved over GR.

 

Since the gravitational force is directly proportional to mass, scientists searched very hard for a geometry which would yield gravity as such a fictitious force. They pretty well failed.

 

I'm only aware of Klein, before Einstein, trying to explain gravity with geometry. I could be wrong. In 3 dimensions this approach is unworkable, so attepts before Einstein seem doomed from the outset.

 

A careful examination of the kinematics of my perspective makes it quite clear that my geometry is in fact readily amenable to the problem of reducing gravitational theory to geodesic motion and I personally have done exactly that.

 

As I've indicated, I fail to see how your perspective differs from special relativity, so it isn't surprising that general relativity works in your geometry.

 

I think things would be much more streight forward if we were to go to a line by line analysis of "A Universal Analytical Model of Explanation Itself".

 

Your paper doesn't seem to have much to do with the topic at hand, which is gravity and time.

-Will

[cwes99_03]

Will, I think you've done the best so far (as long as DD agrees with the what you say which I can't say yea or nea to.)

 

Could you explain the following in greater detail?

 

That clocks measure proper time should be obvious, the time elapsed on a clock should obviously be coordinate invariant.

 

Namely identify proper time and local time and what you mean by coordinate invariant (because two different coordinates can measure the passage of time differently if they are in different reference frames or gravitational wells).