Fred Champion

 

A description that requires four variables. The other part is a straw man; I'm not arguing that the description is a physical thing, but your argument seems to be solely that time isn't an object. I've not seen anybody insist that it is. But in striking down the fourth dimension, you must strike down the other three for exactly the same reason, and I don't recall you doing that.

 

 

 

Matter has a location. That location requires 4 dimensions to describe.

Time is not a component of space (though relativity tells us they are related), so that's a red herring/straw man.

Actually I have stated (although maybe not in this thread) that the three "dimensions" of a cartesian coordinate system are only part of geometry and are imaginary. They are very usefull, but they don't exist. The only real dimension of the volume we call space is place (location).

As you say, matter does have a location. Note that location is not dependent upon a description of that location, even though we find it convenient to describe it relative to other locations. In other words, location requires no dimensions for us to experience it.

We do not experience anything over, through or with time. We may compile memories of different experiences, but each of our experiences is a separate event, an effect which is the result of a physical cause, not a temporal cause. Time is not a cause, it is not an effect, it is not space, it is not a location, it is an artifact of memory.

That seems incoherent to me Fred. Your toe cannot really exist unless time really exists. You can't have your cake and eat it.

Your argument seems circular to me. You say that one's toe exists because time exists because one's toe exists. I say that I can say my toe exists because I experience it, and I have evidence of it that you could confirm even if I did not experience it.

I ask you: what exactly is it of time that we experience? My answer is: nothing.

In introductory physics, a frame of reference refers to a choice of a coordinate system. Inertial frames move at constant velocity with respect to others. Non-inertial ones accelerate. In GR, freefall in a uniform gravitational field is an inertial frame.

 

"The universe" is not a single frame of reference, since an infinite number choices for inertial frames are possible.

There are many different types of coordinate systems. Of course we may choose a particular type from among them. It should be obvious that choosing the type of coordinate system is only the first step in setting up a frame of reference.

The next step is picking a point of origin. A point of origin must be somewhere. In order to pick one place we must have a choice of places. In order for there to be multiple places to choose from, we must posit a volume to contain those places. That volume may be imaginary or real.

If it is real, the volume is the universe. If the volume posited is imaginary, we will find utility in physics for our imagined frame only if we can translate from it into the universe.

A frame of reference is not just a coordinate system; it must include a volume. Our universe is the only real volume we have; within it the point of origin for any coordinate type chosen will be a real place.

I suggest that the type of coordinate system and the point of origin is trivial for any application to the universe. This means that every possible application is essentially the same and will refer to the universe and what happens here. Thus the universe is our one and only real frame of reference.

Light speed is constant only in inertial frames of reference. In a general frame the speed of light will almost never be constant. What do you mean by the "no frame is isolated" statement? We have inertial frames that are not connected by a Lorentz transformation.

 

The CMBR does provide a useful frame to describe cosmology, but this is not a true absolute frame.

We may posit unconnected imaginary frames if we wish, but their utility in physics will be nil. Without a transformation into the universe there is no connection to the universe and thus no utility.

Any coordinate system imposed on any part of the universe is imposed on the entire universe. We cannot separate (isolate) any part of the universe from any other part. I have seen no one claim that the universe is anything other than a contiguous whole.

PeterJ, you correctly point of that we cannot "prove" anything beyond some a priori notions. One of these that I accept is that there must "be" something in order for us to experience it. I prefer to believe that I do not stub my toe on a figment of my imagination. An hallucination may be a "real" hallucination, but the images within it are not real events.

When we consider "time", there is no evidence of anything to experience.

Swansont, I totally understand your insistence on requiring a reference to a particular "time" to describe a particular state. I urge you to consider that a description of a state is not the state, the description is just a memory (or a prediction) of the state.

There is no evidence that any attribute or characteristic of what we call matter or space has any component which we could call time nor that the attributes and characteristics of matter and space are in any way dependent upon what we could call time.

Matter and space are just what and where they are; it is only by our intellect (memory) that we envision a different state, what we call past or future.

Your thought experiment is wrong.

You are using this 'bending' of light as a way to measure and detect absolute speed or velocity and from that, implying that there must be an absolute frame.

 

There is no preferred or absolute frame. There is no absolute speed or velocity, only relative speed or velocity.

And light within an inertial frame doen't 'bend' as it does within an accelerating or gravitational frame.

The thought experiment is correct.

I did not use the "bending" of light in any way. In fact I denied that there is a beam of light which might be described as bending.

Each "wave" of light is emitted from a point in space. (If you don't like the term wave, substitute whatever you use to describe the cause of the effect we call frequency.) Each wave is emitted separately. What we call a "beam" is just a succession of individual waves emitted from the same source. Each individual wave propagates out from its point of origin. If the source of the light is moving, each wave will be emitted from a different point in space.

If you accept that the speed of light (in space) is constant everywhere, then you must accept that light waves propagate at a constant speed everywhere. This speed of light is unchangeable, fixed, not modifiable, in other words, absolute.

Space (our universe) is the frame of reference that light moves through. This is our one and only real, true, absolute frame of reference. No part of the universe may be isolated from any other part. Every other frame of reference you may construct is imaginary, not real.

The speed of light, the propagation of light, the rate of propagation of light waves, is not relative to anything except space. Space is absolute. The speed of light in space is absolute. If you do not accept this, you cannot accept any notion or calculation in all of relativity. The absoluteness of space and light is fundamental to relativity.

As to your last statement, light doesn't bend at all, anywhere. Accelleration may produce the appearance of distortions and gravity may result in distortions. If we cannot accept that space is absolute, how can we accept that gravity produces a distortion in it?

The fact that two objects cannot occupy the same space (you add "at the same time") has nothing to do with time. It has to do with what makes what we call matter matter, and we've been through that. You might as well complain that one object cannot occupy two places (you would add "at the same time"). The matter in space cannot be isolated from space; everything is somewhere. In order for anything to be moved to somewhere else any something else which occupies that somewhere else must be displaced. The state of every object includes the object's place.

You do realize that the constant velocity of light means that if I see a beam of light shining away from me, I will measure it as moving at 186,000 miles per second. If I accelerate in the direction of the light so that I'm moving 100mph, I will measure the light moving 186,000 miles per second faster than me, and if I accelerate in the direction of the light until I'm moving at 185,000 miles per second, I will see the light moving 186,000 miles per second faster than me.

 

That's what light's constant velocity means. There is no preferred frame through which it moves at 186,000 miles per second. It moves trough every frame at 186,000 miles per second relative to that frame.

I believe you do not understand that "constant" means everwhere and that there is only one "real" or preferred frame of reference. An imaginary frame of reference we construct will not be isolated from the one real frame except in our imagination. Light will not change speed as it enters and then exits our spaceship. (I like to travel with the windows open.)

The notion that what will be measured in any given imaginary frame actually reveals what "is" is not correct. What will be revealed is what appears to be, not necessarily what is.

Note that there is no such thing as a "beam" of light; there will be a succession of wave crests (or however you wish to describe what we determine as frequency). The fact that light propagates at a constant speed and we may move at variable speeds is what gives us the component of the doppler shift due to the motion of the observer. Of course the other component of the doppler shift is due to the motion of the light source.

Note that the speed of light does not change because we are moving, even light from a source moving with us. If we travel at half the speed of light in the same direction as the light is propagating, the wave crests will pass us at one-half light speed. If we travel at half the speed of light in the opposite direction as the light is propagating, the wave crests will pass us at one and one-half light speed. If lt did not happen this way we would see no doppler shift.

Convince yourself that light acts this way by imagining we are on a moving spaceship. We shoot a bullet straight up at a target on the ceiling. The bullet will appear to us to go straight up and hit the target. Now we shine a light straight up toward the ceiling. The light will not illuminate the target, it will illuminate a position some distance to the rear of the target, depending on the speed of the spaceship and the distance to the ceiling.

There is no "beam" of light that bends. Each wave crest propagates from the place in space (the one real frame of reference) where it originated and will continue straight up untill it reaches the ceiling. Each successive wave crest will be originated at a place a bit further in the direction of travel than the previous one and will also continue straight up until it too reaches the ceiling. Note that even though the target was directly above the point of origin for each wave crest, the target moves away in the direction of travel before that wave crest can reach the ceiling.

The bullet attains a velocity component from the motion of the ship, but the light does not. The velocity of light is constant everywhere and is independent of the motion of the source. This tells us that there is one real, preferred, "everywhere" frame of reference.

 

That's the whole point.

 

You have used 'time' by stating that the states have to be 'previous'.

 

Furthermore you assert that time does not exist, yet you tell me that it can be measured.

 

How can it be measured if it does not exist?

 

What do you mean by exist?

I believe we do not remember or record states which have not happened, thus everything remembered or recorded is previous. "Previous" is not an attribute of time. It is just a term we use to acknowledge memory.

I hope I have not stated that time can be measured. What we do when we envision the "passage of time" is compare our memory or records of states of some objects with our memory or records of states of others. All measurement is simply an act of comparing one thing to another.

You ask "What do you mean by exist?" This is a philosophical question. I accept that we can say that "something" exists when that "something" presents evidence of identity. The only way I know of for evidence of identity to be communicated is by interaction with the "something's" surroundings. All phenomena we experience are the effect of that interaction. As I have stated, we cannot deny that any posited "something" has a state of being simply because we cannot experience it, but without evidence of it we cannot affirm existence. (I can accept that there may be a state of being - different from a state of existence - wherein interaction with surroundings does not happen.) I am not aware of any evidence at all of the "something" called "time" interacting with anything or lurking about in a state of being; it is a product of intellect, an artifact of memory, imaginary, virtual, not real. Enough philosophy.

To paraphrase a recent burger commercial, if you want us to accept "time" as real, where's the beef?.

Is not time simply matter in motion. If all matter stopped moving, would not time cease to exist?

I hope my response to studiot answers your question.

I think it is very interesting just how difficult it is for us to give up the idea that time is a real thing. The implications of something permanent in a transient existence are hard to resist. People, including many in the science community, love the idea of time travel, even though it is totally inconsistent. We are wonderful beings.

The shift during acceleration will be small. That's why I set the twin's clocks two light seconds apart. After reaching .5c the twin would see a shift of only .5 second in each clock. At any reasonable length for the ship the effect would be practically negligible.

However, I did point out that there would be apparent displacement of objects not along the ship's centerline. This will be significant. Example: Set the direction of "forward" at 0 degrees and "rearward" at 180 degrees. As the speed approaches c, light leaving an object 45 degrees from forward will reach the twin when he has traveled .707 times the distance to the object. In other words, the twin will "see" the object at 90 degrees from forward.

Note too that the profile (rate and duration) of the acceleration doesn't affect the final apparent shift, only the amount and duration of the doppler shift during acceleration. I have seen a couple of posts where there was some concern about how quickly a constant speed was reached. We all recognize the effect of acceleration is cumulative.

 

No this would imply that time is or measures change change.

 

But, as I pointed out earlier, time can also measure lack of change.

Of course we use the term "time" as our measure of recognized change, our memory of previous states.

Unless there is change, there is no interaction, no communication, no experience, no phenomena, no means of measuring. Any object with an absolute unchanging state cannot be said to exist because it will not be presented for recognition. We may not be able to deny that any posited object has a state of "being" but we cannot recognize it as existing without evidence of it interacting with its surroundings.

Edgard, you are right about at least one thing; there is one absolute frame of reference. It is the space in which light propagates. If one accepts that the speed of light is constant in all frames of reference, then one must accept that no reference frame is isolated from any other reference frame.

Your notion of birds carrying information may be correct, but it makes my brain hurt.

I believe what you are actually questioning is how we measure without touching. Unless you accept a defined frame of reference and a means of communication moving at a defined velocity within that frame of reference (and all other frames), you have no basis for consistent measuring without touching. This is what we have with space and light, an absolute frame and a constant velocity means of communication.

I'm sure you will recognize that, for any object, the maximum velocity that can be measured is less than (or possibly just equal to) the velocity of the means of communication. One cannot measure supersonic speeds using only sound, nor super-light speeds using light.

How can you observe Doppler shift from something that is stationary with respect to you?

You are correct, the twin will not observe a doppler shift in the frequency of light from the clocks at a constant speed. I don't know why I wrote that last sentence of my previous post that way. Of course a doppler shift in light will be observed only when the observer's velocity is different from that of the source. I did a lousy job of expressing my thoughts. I'm really sorry for the confusion.

What I was trying to convey is that the "shift" in the light received from the clocks will still be present. It will not be recognized but will have to be "unwound" as the ship decelerates back to a rest state. The reason it will not be recognized is that the twin will not compare the number of cycles of the light he receives from each clock. I don't know how to say this any better than with an illustration.

Suppose the twin has set up his clocks so that the forward clock will transmit the video part of a movie and the rear clock will transmit the audio part. As he accelerates the video and audio signals the twin receives will not be in sync. When he decelerates to a rest state the video and audio will sync again.

 

The clocks are not moving relative to the twin.

You are correct, the clocks are not moving relative to the twin. However, the light emitted from the clocks has received no velocity component from the motion of the clocks. Light is emitted from a specific point in space and will propagate from that point in all directions at c.

An object thrown on a moving platform does have a velocity component from the motion of the platform, but this is not so for light.

 

 

How so? Each observer is by definition not moving with respect to his clock. How can there be a doppler shift in the same frame?

 

I don't see how to reconcile this statement with the Einstein clock synchronization protocol.

 

Einstein told us that the speed of light is constant - everywhere. The motion of the source of the light, whether an originating source or a reflector, will not increase nor reduce the speed of the light emitted or reflected from the source.

This tells us that light inside the moving twin's spaceship will have the same speed as light outside the ship.

Llight from the forward clock will reach the twin faster than light from the rear clock because the twin is moving.

Once the ship reaches a constant velocity the clocks will appear to run at the same rate even though the forward clock will appear to have "gained" time and the rear clock to have "lost" time. The twin will still observe the doppler shift in the frequency of the light from each clock.

Wow, this thread has been fun reading. I believe there is only one item I could inject which has not been brought up. Throughout the discussion the moving twin's clock has been taken to be in a position such that the moving twin sees his clock's rate as constant and, by implication, sees no doppler shift in the light coming from (reflected from) the face of his clock.

This situation is not likely. The position of his clock relative to the moving twin will determine what he sees. His perception of his clock will change as his (and his clock's) velocity changes. The differences in his observations of his clock are easiest to determine when the clock is forward or to the rear of his position; positions to either side require just a bit more (but not much) math.

Didymus might want to consider what "time" the moving twin would see when he has two clocks, one ahead and one to the rear. I suggest the scene be set such that he has a very long spaceship with one clock is 186,000 miles forward of his position and the other 186,000 miles to the rear, the clocks synchronized to show the same time while at rest. The basic point is that changes in the time observed on each clock will occur during acceleration, not at constant velocity. A bit of calculation with positions of clocks, or other objects, to the side of the moving twin's position will demonstrate apparent movement of those objects, also occuring during acceleration and not at constant velocity.

The really fun part is that all the apparent changes can be calculated with simple math and without any knowledge of relativity.

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As far as I can see your strategy does not eliminate time from the equations but simply renames it.

 

...

You make my point exactly. What we experience is not time, it is changes in states of objects. It is these phenomena that have been renamed "time".

Since you have invoked the dreaded 007, to quote him

 

 

 

And yet in another thread you were adamant that your eye was the only true origin and continued quite a lively discussion about this assertion.

 

You cannot have it both ways.

 

I doubt that you have any idea what I was alluding to when you made the above response,

 

Yet you did not ask

 

But in IMHO the real issue is as 007 says, you do not listen to any one else.

 

A discussion involves exchange of ideas: I have acknowledged your good ones, but you have steadfastly refused to listen to any of mine or from anyone else.

 

If you could do this there is a real danger that you might learn something new and of possible value.

I believe you are correct. I had no idea you were attempting allusions to illusions.

I miss proper spelling of my user name even more, Ferd.

Please accept my sincere apology for the spelling error. I intended no slight.

There seem to be times when my dyslexia (mild) breaks the path between my brain and my fingers. Letters such as "n" are sometimes turned backwards by part of my brain and apparently another part recognizes the error and occasionally rather than correcting it, just eliminates the letter altogether. I don't get called out on spelling very often. I suspect most errors are either not noticed or taken to be typos. Of course when an error is in someone's name then it is recognized. One interesting part, to me, is that I do much better reading at speed, recognizing whole words, and not trying to see the individual letters. I know one woman who is just the opposite, she has to see the spelling of every word and will comprehend almost nothing if she doesn't read slowly.

It's over my head most of this, but a few thoughts...

 

I would recommend Hermann Weyl's book on the continuum. He is clear. Time is not an empirical phenomenon but a creation of reason and intellect. He draws a careful distinction between the arithmetical view of time and the view by which it is a true continuum. For Weyl all co-ordinate systems would be emergent.

 

His view has explosive implications for all sorts of things but it seems to be largely ignored. Still. at least Fred should be able to call on Weyl for support.

 

Swansont makes the point that being real and being fundamental are not the same thing. I think this is wrong, but then I use the words differently. Time may be real in some sense but it cannot be fundamental and so cannot be independently real. All in all I'm with Fred on this.

 

Time is a philosophical problem and I see no use in referring to scientific experiments (Pauli etc) for support for any particular view of time. Rather, I'd say the foundations of analysis are a sensible place to start, following Weyl's lead.

I have not found Weyl's book on the continuum, but I did read his book on space - time - matter. I find no support there for my position on time. Yes, he does admit that time is a product of the intellect, but he embraces the notion that so is everything else we experience and thus time can (must?) be considered as real. To me, he comes off as another apologist for the standard idea of a space-time continuum.

I don't see time as a philosophical problem any more than the notion of a flat earth or the emperor's clothes are philosophical problems. OK, so perhaps they are, but that's another topic. To me the problem, if we can posit the notion of time as a problem, is one of analysis. Suppose we replace the "t" in all our equations with another term. For this term I suggest "poc". Poc is short for "phases or cycles". Poc may be expressed in whatever units are convenient for the calculation, swings of a particular pendulum, phases of the moon, the Earth's transit of the sun, etc. Note how the notion of time as a phenomenon has been eliminated from the equations and how we have returned to the source, our experience, the phenomena, our recognition (memory) of changes in state. The "physics" we experience is not of time but of the state of objects.

actually we do have the technology to emit a single photon and detect a single photon, as well as entangle two photons together

 

http://www.toshiba-europe.com/research/crl/qig/quantumdots.html

http://www.toshiba-europe.com/research/crl/qig/singlephotondetection.html

http://www.toshiba-europe.com/research/crl/qig/singleelectronspingeneration.html

http://www.toshiba-europe.com/research/crl/qig/singlephotonsource.html

http://www.toshiba-europe.com/research/crl/qig/entangledled.html

 

its pretty obvious just from that alone that photons do exist, in the same way any particle exists with an energy/mass relation. Photons mediate the electromagnetic force. That includes light.

 

• Photons are the force carriers of the electromagetic force
• W and Z bosons are the force carriers which mediate the weak force
• Gluons are the fundamental force carriers underlying the strong force

in other words their interactions with their environment is how the force is carried. with photons their interactions has wave like properties. So it can be treated mathematically as both a particle and a wave

Thanks for the links. I will study the info. Got to go back to solitary for a while. I bet Swansot will miss me.

 

So why can't I just pretend to be in the center of mass of a system in order to figure something out? What is invalid about that approach? Why would I have to physically be there?

You may set up any imaginary volume and impose upon it any imaginary coordinate system you can imagine. I expect you will recognize that in that situation you will not be making observations; you may be describing observations or you may be making predictions, or you may be just doing geometry or math. What you figure out may be as valid as the conditions you set up and the methods you apply. My experience is that the problems, if there are any, will come when you try to carry some conclusion from an imaginary environment into our actual environment.

Fred, I find your idea of a frame of reference far to limited and constraining.

 

Why should it be constrained to someone's eye?

 

What if I wished to consider the mechanics inside a solid body?

Where would I place my eye?

 

I say this because there are 'preferred frames of reference' in such circumstances (ajb has already referred to these).

 

The OP has perfect, I agree with ajb preferred is a better word - nothing is perfect.

 

In the example I just gave we call these preferred axes 'Principal Axes', and the (preferred) frame of reference is defined by these.

The individual's "eye" Is just a shortcut way of saying his/her point of viewing, or perhaps more properly his/her point of "experiencing". We will make observations and describe them from a single point of viewing.

You may set up any imaginary frame of reference you can imagine. I expect you would base the conditions for your imaginary frame of reference on some set of actual observations. My response to you is the same as my response to Swansot above.

 

"We"? "Our"? My eye is not co-located with your eye, and I may be moving with respect to you. On what basis do you deem your frame of reference real and my frame of reference imaginary?

I think you take the meaning of my statement wrong. Of course yours is as real as mine.

The origin of every frame of reference, actual or imaginary, is presented as the viewing point of a single observer; it has to be, there can be only one viewing point per observer.

Translation from one observer's origin to another's is, as you point out, in terms of displacement within the frame of reference. If one observer recognizes a second, then both observers share that frame of reference. Observations from each observer are made and must be presented from each observer's viewing point (literally, each observer's point of view).

I don't know much about amplitude. Don't know enough to agree or disagree about amplitude changing at a frequency. That's why I asked the question. What I've found so far seems to imply that amplitude may be more variable at lower frequencies. If that is so, then there is some reason for it.

Since the photoelectric effect is seen to be frequency dependent, could it be that amplitude at those frequencies is so close to being constant and is so small that it is just not significant (in terms of the energy imparted)? I believe higher amplitude is credited with greater energy transmission at the lower frequencies. I was thinking that if there is that relationship there might be limits.

If I read your second paragraph correctly you are saying that intensity and amplitude are the same thing (the number of photons). I didn't get that from what I've read. I thought the light in a photon has both frequency and amplitude. And I don't understand your statement about generating arbitrary amplitudes in empty space at all. Not a criticism, I just don't get it.

To be honest, amplitude makes sense to me only in a wave model.

So then, how much more "official" could a consensus - community - definition get than to be written down for all to see? And if it is not written down and presented in a source which can be cited are we left with each individual or local group remembering some slightly different version? But wait, isn't that exactly what my definition is, just a slightly different version?

I will hit this one more time and then (probably) give up. We live in an actual, or real, or physical, frame of reference. The universe is the volume we exist within. Our coordinate origin, our zero point, is the eye of the observer. Our orientation, our zero angle, is the direction we look in when we pick an object to use as a reference for specifying the positions of other objects. Gravity determins the "up" and "down" and "horizontal" of our orientation. Our perception of "near" and "far" provide our metrics. We inhabit one and only one actual universe and have one and only one actual coordinate system for each actual individual. The combination of the volume we inhabit and the way we experience it is not just our "preferred" frame of reference, it is our only actual frame of reference. We do not construct it, we have discovered it.

Any other frame of reference we may construct, the combination of a volume and a coordinate system imposed upon that volume, will be imaginary. A coordinate system not imposed upon a volume is a concept only. It provides no means for describing actual nor imaginary observations. A coordinate system without some volume combined provides no "where". Without a volume there is no place for the objects that would be observed or described.

Not to me, and not to the physics community in general, for some of the reasons already discussed. Personal incredulity isn't a particularly effective argument.

 

It's trivially not. I've had plenty of lasers in the lab where I can dial up or down the amplitude and keep the frequency constant; that's known because it's servo-locked to an atomic transition.

I am quite impressed that someone who is able to speak for the "physics community in general" is willing to converse with me. Wow. I must ask if you accept that personal credulity is "a particularly effective argument"?

Sorry about the third paragraph of post 17. Was interrupted. Couldn't continue. Did not have time to develop the thought. Should not have hit the "post" button. Yes of course amplitude is variable, at least to some extent.

In trying to look into the amplitude of light (and sound too), I haven't been able to find out if there are limits. Most published info I have found deals with noise as the factor limiting fidelity (in sound and light) and doesn't address physical (perhaps theoretical) limits of amplitude. Do you know if there are upper and/or lower limits on the amplitude of light?

The reason I ask is because I suspect the most revealing part of light amplitude will be the limits (if there are any) and they might shed some light (pun intended) on the nature of the transmission process. I am speculating only that something might be learned, not on what might be learned.

I don't know whether "light" is a wave or a particle. I suspect we may never know. As far as I know we have no way of observing light being emitted nor transmitted; we observe only the effect of light encountering matter (and responding to gravity).

The statement that "quantized absorbers are frequency selective" certainly implies that the effect may be due to characteristics of the absorber. The observation that the effect varies from one absorber to another seems convincing does it not?

I did not introuduce amplitude of light into the thread. Seems to me that amplitude should be constant for a specific frequency.