Is 'time' a measurable variable?

[HydrogenBond]

One way to measure time independantly of gravity wells is to use energy. Photons give off exact frequencies. Don't we measure historic time all of the universe based on energy. It appears immune to gravitational disturbances over billions of years. If it isn't, universe sized distance and time could be way off.

[Erasmus00]

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.

 

Proper time is the time an object experiences. Lets have two people, Alice and Bob. They both have clocks strapped to them, and they are moving relative to each other.

 

The clock strapped to Bob measures Bob's proper time. The clock strapped to Alice measures Alice's proper time. However, the clock strapped to Alice DOES NOT measure Bob's proper time, but rather Bob's "coordinate time" within Alice's frame.

 

Now, why should proper time be invariant? Simple: Imagine Bob starts on Earth and carries a clock to the moon. The proper time that elapses between Bob leaving Earth and landing on the moon is measured on his clock, and the reading on a clock is an unambiguous thing. Two different observers might disagree at what time on their clock's Bob arrived at the moon, but everyone should agree "when Bob landed on the moon, the face on his clock said X."

-Will

[EWright]

Proper time is the time an object experiences. Lets have two people, Alice and Bob. They both have clocks strapped to them, and they are moving relative to each other.

 

The clock strapped to Bob measures Bob's proper time. The clock strapped to Alice measures Alice's proper time. However, the clock strapped to Alice DOES NOT measure Bob's proper time, but rather Bob's "coordinate time" within Alice's frame.

 

Now, why should proper time be invariant? Simple: Imagine Bob starts on Earth and carries a clock to the moon. The proper time that elapses between Bob leaving Earth and landing on the moon is measured on his clock, and the reading on a clock is an unambiguous thing. Two different observers might disagree at what time on their clock's Bob arrived at the moon, but everyone should agree "when Bob landed on the moon, the face on his clock said X."

-Will

 

Why X and not IX or VII? :hihi:

[Qfwfq]

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.

Momentum in the tau direction is called total energy, E is the symbol often used.

 

[math]m^2 = E^2 - p^2[/math]

[cwes99_03]

Proper time is the time an object experiences. Lets have two people, Alice and Bob. They both have clocks strapped to them, and they are moving relative to each other.

 

The clock strapped to Bob measures Bob's proper time. The clock strapped to Alice measures Alice's proper time. However, the clock strapped to Alice DOES NOT measure Bob's proper time, but rather Bob's "coordinate time" within Alice's frame.

 

Now, why should proper time be invariant? Simple: Imagine Bob starts on Earth and carries a clock to the moon. The proper time that elapses between Bob leaving Earth and landing on the moon is measured on his clock, and the reading on a clock is an unambiguous thing. Two different observers might disagree at what time on their clock's Bob arrived at the moon, but everyone should agree "when Bob landed on the moon, the face on his clock said X."

-Will

 

Thus with that I begin to see DD's question and point of view. Calling it proper time and saying that each clock can measure a different proper time sounds like it is not in fact proper time. Instead it is reference time, being tied to the clock's frame of reference. What DD seems to be defining as proper time is universal proper time, a central clock if you will that measures the passage of time without respect to any frame of reference. His argument thus seems to be that such does not exist.

How that point specifically is tied to GR or SR, i'm not completely sure, except that this question is only raised because of understanding of SR and GR and their effects on measurement of time in two different reference frames.

 

One way to measure time independantly of gravity wells is to use energy. Photons give off exact frequencies. Don't we measure historic time all of the universe based on energy. It appears immune to gravitational disturbances over billions of years. If it isn't, universe sized distance and time could be way off.

Thus the point of my earlier post, Will, about the age of the universe. Energy is completely dependent upon gravity wells. Light waves travel through space time which has, as a component, curved space around gravitational wells.

[Erasmus00]

Calling it proper time and saying that each clock can measure a different proper time sounds like it is not in fact proper time.

 

But between any two events there can only be 1 proper time. Proper time is considered "proper" because its invariant, every person, regardless of reference frame, can agree on it.

-Will

[Buffy]

What DD seems to be defining as proper time is universal proper time, a central clock if you will that measures the passage of time without respect to any frame of reference. His argument thus seems to be that such does not exist.

Which oddly enough is *exactly* what Uncle Albert says! :confused: So what's the contradiction that disproves SR?

 

Unstuck in time,

Buffy

[InfiniteNow]

In hopes of adding some further clarity to the situation, the term "proper" is often used to refer to one's own.

 

My proper username is InfiniteNow.

My proper dog is sometimes not so proper...

 

 

Hence, Bob's proper clock is the one he sees.

 

Cheers. :confused:

[cwes99_03]

Yup.

[Buffy]

ditto! :hihi:

 

When *I* use a word, said Humpty Dumpty, :confused:

Buffy

[ldsoftwaresteve]

Ok. So if it's measurable, show me the unit of measure.

[Doctordick]

Boy, what made this thread so popular all of a sudden? Sixteen posts in 24 hours!

So what's the contradiction that disproves SR?

I have utterly no argument with the experimental aspects of SR. As far as I am concerned, there are many problems with Einstein's space-time continuum, but I would say that the incompatibility of his GR with QM is the only "gross" failure. And believe me, I do not propose throwing it out; for some problems, it provides an excellent foundation for calculating some important results: i.e., I think it is a very useful mathematical structure.

But!!!

:hihi:

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.

Direct measurement of "real time" and establishing (I would rather use that term then measure) a relationship to "real time" are not the same thing. I know it's a bit subtle but if you will indulge me I think I can clarify what I mean.

 

For the simple sake of argument, let's go back to Newton's representation of mechanics. Newton used t as an evolution parameter of the phenomena he was describing with his mechanics. His basic relationship, F=ma, was valid only in what he called an inertial frame and he certainly believed general relativity (how one transforms a solution in one frame to a moving frame) was a valid concept of interest to science. A significant portion of his work was dependent on exactly that issue (both Coriolis and centrifugal forces are consequences of Euclidean general relativity).

 

There are two quite different but equally significant issues to be brought forward from this point. One has to do with time and the other has to do with what, in my day, was called pseudo forces: the fictional forces created by working in an non-inertial coordinate system. Pseudo forces have a curious characteristic: they are all directly proportional to mass (that is a consequence of the fact that the acceleration is actually an acceleration of the reference frame and not an acceleration of the massive objects being represented). Noting that gravitational forces are always proportional to mass, many people tried to find a geometry which would reduce gravity to a Pseudo force. They utterly failed, in fact Maupertuis finally proved that no geometry with a Euclidean metric existed which would yield gravity as geodesic motion. When I was a student, it was held as a fact that Einstein had 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".

 

Returning to the issue of time:

Now Newton didn't think about the problems of actually establishing his ideal frame of reference, he just assumed it was possible (as do most laymen to this very day; as can be seen from most arguments against modern relativity). Personally, I think that if he had ever just taken a moment to think about the problem, we might have gotten a solution long before the conundrum was brought to a head by Maxwell's work. But that is just an opinion, the fact was (and is) that the universe around him contained all kinds of repetitive systems which were commonly used to "measure time" and he developed his mechanics in terms of those repetitive phenomena using "time" as an evolution parameter presuming that the measurement of time was a trivial and insignificant issue.

 

Newton set up his mental picture as to what was going on in terms of a three dimensional Euclidean space where objects moved through that space as time evolved. The position of an object in space was described by (x(t),y(t),z(t)). One of the major conveniences of his representation was the fact that very complex collections of objects could be represented with a set of such parametric representations, all using exactly the same t. The time evolution of the details within substructures were described by exactly the same parameter as was any other aspect of the system (that was essentially the fundamental concept of simultaneity).

 

Now, along comes Maxwell and blows Newton's boat out of the water. I won't go into the thoughts leading up to Einstein's solution as you are all quite familiar with that event. SR (no acceleration between frames) requires only the transformation relationships and really cannot be seen as overwhelming support for the space-time continuum so it really follows that one of the most important aspects of Einstein's introduction of his space-time continuum was his the solution to that old gravity problem. (Plus that, to my knowledge, no one else even proposed a solution to the problem of a "General" coordinate transformation which certainly was absolutely necessary.)

 

However, Newton's picture was so entrenched that even Einstein cast his solution in a form amenable to the old (x(t),y(t),z(t)) representation of object paths by dropping the significance of simultaneity. Embedded in that representation is the idea that, if the exact state of the present is known, the state of the future is also known: i.e., concept of simultaneity serves no purpose to physics. When he did that, that major convenience of the representation mentioned above was lost "the fact that very complex collections of objects could be represented with a set of such parametric representations, all using exactly the same t". One is now required to make extremely complex corrections to the laws of physics in order to make them frame independent (they have to be expressed in a "covariant" form).

 

It turns out that there exists another, quite simple, solution to the difficulty presented. If one expands Newton's three dimensional Euclidean space to a four dimensional Euclidean space (adding a real tau axis) where all entities of interest are momentum quantized in that fourth dimension (my definition of rest mass), a number of rather astounding consequences occur. First, if everything is momentum quantized in the tau direction then the Heisenberg uncertainty in tau is infinite and the added dimension simply vanishes from view. We certainly can not see it; however, it does have some very significant kinematic consequences.

 

Secondly, as mass now vanishes from the QM equations of motion, the free motion equations have the form of E = |p|c which essentially amounts to a very simple wave equation. At this point, t can be defined as the variable canonical to Energy. (From a Newtonian perspective, we need to design a clock to measure t and I will get to that.)

 

Third, if all forces are to be implemented through exchange phenomena, we end up with a very significant fact: all "force fields" arise from massless exchange effects and all interactions display exactly the same transformation characteristics as does Maxwell's equation. Calculation of physical "dimensions" of stable objects obey exactly the same rules as does standard relativity which simply means the stable solutions simply change with the reference frame.

 

Fourth, if one goes to design a clock in this picture, one will discover a very significant fact. All clocks, totally independent of their motion, will actually measure exactly the displacement of the wave function in the tau direction. Not the actual value of tau (that can not be known), but the change in tau required for one cycle of the clock: i.e., our supposed clock ends up measuring dtau. But this construct is, up to this point, a strictly Euclidean space. That means that the metric is of the form ds = cdt = sqrt(dx^2 + dy^2 + dz^2 + dtau^2 ) and that supports the differential relationship +idtau = sqrt( dx^2 + dy^2 + dz^2 -(cdt)^2) which is exactly the form of Einstein's space-time metric. It has one strange but interesting characteristic: dtau is imaginary for Einstein's space like intervals. Note that no object in Einstein's picture can follow a space like path (which do exist in his geometry) while no such path even exists in this representation.

 

Fifth, we end up retaining that convenience of Newton's representation that very complex collections of objects can be represented with a set of wave functions, all using exactly the same t. The time evolution of the details within substructures can be described by exactly the same parameter as was any other aspect of the system (the fundamental concept of simultaneity returns).

 

Finally, the most significant is probably the failure of Maupertuis' proof. His proof depends upon the fact that various massive objects have different velocities. In this case, all entities have exactly the same velocity and his proof just doesn't apply. In fact, I have myself worked out a geometry which reduces gravitational theory to geodesic motion. However, one can stay in a Euclidean geometry by letting the speed of the QM wave function vary with exchange interaction density (it thus becomes a refractive effect which is much more easy to implement). What is really important here is that no conflict between QM and GR ever arises.

 

I have always said that everyone's view is blocked from seeing what I just shown you by their insistence that clocks measure time. What I was talking about was their refusal to see proper time (what clocks do measure) as a real axis.

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

If you understood what I just presented, you should understand that I have really changed nothing in the final appearance of the universe or the use of common devices, just presented a starkly alien foundation for it. A foundation which, though it might be very alien, is actually quite simple compared to Einstein's GR and far more universal.

 

Didn't mean to disturb all of you -- Dick

[Erasmus00]

First, if everything is momentum quantized in the tau direction then the Heisenberg uncertainty in tau is infinite and the added dimension simply vanishes from view.

 

I reiterate an earlier post I made. First, this is not new, but the standard energy/time uncertainty, known since Dirac. Second, the uncertainty is only infinite if the mass is exactly known, and it cannot be, due to vaccum fluctuations, etc.

 

and all interactions display exactly the same transformation characteristics as does Maxwell's equation.

 

[..] But this construct is, up to this point, a strictly Euclidean space. That means that the metric is of the form ds = cdt = sqrt(dx^2 + dy^2 + dz^2 + dtau^2 )

 

Your metric is broken. Transformations that leave Maxwell unchanged alter the form of your metric.

 

I have always said that everyone's view is blocked from seeing what I just shown you by their insistence that clocks measure time. What I was talking about was their refusal to see proper time (what clocks do measure) as a real axis.

 

The reason no one uses proper time as a "real axis" is that it doesn't lead to a proper metric. Your resulting metric is not invariant under the same group that leaves Maxwell invariant.

 

And anyone who works regularly with SR/GR is familiar with what clocks measure. I sometimes feel that your disagreement is with a misrepresentation.

 

Lastly, as to your claim that this rectifies the conflict between general relativity and quantum mechanics, I fail to see how. The conflict occurs because of the energy/mass relation (which you use) and the energy time uncertainty (which you also use). Einstein's field equations, which would be similar to yours, do not handle well the mass-density fluctuations that this implies. Also, you haven't talked of how you would quantize a field in your scheme, but I can't see why it would be different then standard qft, so you'll still have the zero-point energy problem.

-Will

[ughaibu]

How can one measure the future?

[Qfwfq]

In hopes of adding some further clarity to the situation, the term "proper" is often used to refer to one's own.

And that's exactly why it's called proper time!!!!! ;)

[InfiniteNow]

And that's exactly why it's called proper time!!!!! :cup:

Yeah, it's just that many of us blokes in the States interpret the word "proper" to mean "correct." I felt that there would be more than one reader confused by this.

 

Now (pun intended), back to the discussion on temporal measurement. :)

[Doctordick]

I am sorry Erasmus00, but I am afraid you have simply failed to follow what I said.

I reiterate an earlier post I made. First, this is not new, but the standard energy/time uncertainty, known since Dirac. Second, the uncertainty is only infinite if the mass is exactly known, and it cannot be, due to vacuum fluctuations, etc.

First, in my representation, momentum in the tau direction is rest mass and not energy. Furthermore, vacuum fluctuations are a consequence of virtual interactions which are as applicable in my representation as they are in the standard representation. With regard to the accuracy with which rest mass is known, (where half life is considered to be the conjugate of rest mass) check out the estimated half life of a proton. (You will find it represented in time but, in order to represent it in my representation, you will have to convert it into the distance light would travel in that time.) It is not a very short distance and, with reference to the size of the universe, it can pretty well be approximated by infinity.

Your metric is broken. Transformations that leave Maxwell unchanged alter the form of your metric.

You are totally doing the problem incorrectly. You have to watch yourself very carefully. It is the laws of physics which remain unchanged in such a transformation, not your measurements. Since all forces arise through massless exchange forces, the stable states of all your measuring devices end up shifting in exactly the way as do the solutions of Maxwell equation and it turns out that the laws of physics simply are not a function of your frame of reference. (You have to work it out, not just presume the answers.)

The reason no one uses proper time as a "real axis" is that it doesn't lead to a proper metric. Your resulting metric is not invariant under the same group that leaves Maxwell invariant.

That's because you are not taking that fourth real axis into account.

And anyone who works regularly with SR/GR is familiar with what clocks measure. I sometimes feel that your disagreement is with a misrepresentation.

So we are back to "clocks measure time by definition are we? So be it, I guess you just can't follow what I am saying.

 

Have fun -- Dick