Types Of Clocks Which Have Actually Measured Time Dilation

[exchemist]

Been there, said that.  Didn't make much impression.

Ah OK, I confess this thread jumps around so erratically that I have given up reading through it in an attempt to follow whatever train of thought there may be presumed to be in it. So I'm just reacting to obvious bits of science that seem to require comment.

Edited May 29, 2017 by exchemist

[mrg]

 So I'm just reacting to obvious bits of science that seem to require comment.

 

Yeah ... it's hard to keep up with everything that's said in threads.  I find that AFP is inclined to ask questions -- but when given an answer, simply stops for a moment, then thinks up another question.

[OceanBreeze]

But what about absorption of radiation by matter? Is that not energy "condensing"? You start with some matter and some radiation. And you end with just matter, the radiation having made the matter a bit heavier, in accordance with your beloved formula.

 

(And if you insist on pure radiation-to-matter conversion, you can look up "pair production".)

 

But in this case, (absorption of radiation) the amount of matter hasn’t changed, only the mass has increased. Even heating an object, or compressing a spring, will increase the energy and therefore the mass of that object, but has no effect on the amount of matter.

 

So, I guess we need AFP to define what he means by “condense”. Does he mean energy into matter or energy into mass? (The last one is redundant)

 

Pair production may be the only example of energy into matter (that I know of) but as I understand it, the particles so produced will soon annihilate one another and then it all goes back to just energy in the form of lower energy photons.

Or am I wrong about this?

[exchemist]

But in this case, (absorption of radiation) the amount of matter hasn’t changed, only the mass has increased. Even heating an object, or compressing a spring, will increase the energy and therefore the mass of that object, but has no effect on the amount of matter.

 

So, I guess we need AFP to define what he means by “condense”. Does he mean energy into matter or energy into mass? (The last one is redundant)

 

Pair production may be the only example of energy into matter (that I know of) but as I understand it, the particles so produced will soon annihilate one another and then it all goes back to just energy in the form of lower energy photons.

Or am I wrong about this?

Well that's a nice point, I'd have thought. The mass has increased and the energy and matter have combined together. But "condense" is AFP's term, I agree.

 

I have an uneasy feeling there may be, lurking round the corner, some conflation of the matter and radiation processes we have been discussing with the 2nd Law of TD and entropy increase. Now that, certainly, could be described as a principle according to which energy tends to "disperse" and does not spontaneously re-concentrate itself.

 

You read it here first. Crash helmets on!

Edited May 29, 2017 by exchemist

[mrg]

 Now that, certainly, could be described as a principle according to which energy tends to "disperse" and does not spontaneously re-concentrate itself.

 

The old "heat death of the Universe"?   Hardly news that the Universe is running out of free energy.

 

BTW, does Oxford do a lot more science than Cambridge?   I recollect seeing a lot more mentions of research out of Oxford, but I could be wrong.

[exchemist]

The old "heat death of the Universe"?   Hardly news that the Universe is running out of free energy.

 

BTW, does Oxford do a lot more science than Cambridge?   I recollect seeing a lot more mentions of research out of Oxford, but I could be wrong.

No it's pretty equal. Oxford has, or had, the biggest chemistry school in the country, but Cambridge is renowned for its maths and physics - as is Imperial College, in London University.

 

Re 2nd Law I'm just speculating where AFP gets this idea of energy "dispersal" from. But of course that entails energy being ultimately converted to heat, which is a property of matter in thermal motion. So the dispersal in question results in a lot of matter with randomised internal kinetic energy, rather than radiation. So it is a different idea from his E=mc² matter <-> radiation interconversion.

Edited May 29, 2017 by exchemist

[mrg]

Well, matter is converted to radiation in stars, eventually the stars fade out, and that's all she wrote for the Universe.  "Welcome to Millaways!"

Edited May 29, 2017 by mrg

[AmishFighterPilot]

I apologize for mangling terms. What I'm saying is that energy radiates out from its source, but it never reunites without outside influence. Gravity does seem to work the opposite way, geometrically.

 

I'll reply more as soon as I can, but I'm pretty busy moving a cat sanctuary

[exchemist]

I apologize for mangling terms. What I'm saying is that energy radiates out from its source, but it never reunites without outside influence. Gravity does seem to work the opposite way, geometrically.

 

I'll reply more as soon as I can, but I'm pretty busy moving a cat sanctuary

What you mean, I think, is that radiation, not "energy", radiates out from its source. Energy is present in many forms, most of which do not involve any radiating.

 

Gravitational influence, being due (in Newton's conception of it) to a static field rather than anything in motion, doesn't either. You can draw "field lines" to indicate how the strength of the field varies with distance, just as you can for a magnetic or electric field. These lines, geometrically speaking, diverge from - or, equally, converge towards - the centre of mass. But nothing moves: it is just a field.

 

In Einstein's formulation it is a curvature of space-time, but that too is a static feature.

[JMJones0424]

It doesn't move "in one direction only" so much as it "moves". So even if a given frame moves opposite to another, its defining space-time by ensuring cause always preceeds effect.

This is precisely the reason why, when we include the concept of entropy, time must move in the same direction as entropy.  Time does move "in one direction only" as we have observed, but we do not have a good explanation of why this is the case, despite emphatic assertions that it must. Even if someone's frame of reference moves opposite to another's, there is never a case where time reverses direction.  You recognize that cause precedes effect because this is how we experience time.  But there is no good explanation for why this must be the case.  Every test shows that this is the case, but we have no straight answer for the mechanism of time that shows that the increase of entropy must be tied to the flow of time.  To be fair, my understanding in this realm is sub-par.  It may be the case that in my ignorance, I am missing something that clearly ties the arrow of time with the arrow of entropy.  I have not yet been made aware of such a thing.  Given my limited knowledge, the most accurate response that I can give is that we don't know that time must only move in one direction, though we haven't observed time to move in anything other than in one direction.  We certainly don't know of any mechanism for time.

 

When you introduce Special Relativity and frames of reference, the definition of the rate of time moving becomes dependent upon the relative movement of two observers, but there is not an experiment that I am aware of that shows time moving in any direction other than forward.

 

To get back to your original question, there are numerous clocks that actually measure time dilation.  This is one of the most strenuously tested predictions of General Relativity.  GPS wouldn't work if atomic clocks didn't react differently depending on relative position and velocity to known points.  It is not possible for the speed of light to be universally measured if the passage of time was a universal constant.  Numerous tests have shown that the passage of time is a local phenomenon, such as the Hafele-Keating experiment.

Edited May 31, 2017 by JMJones0424

[AmishFighterPilot]

What you mean, I think, is that radiation, not "energy", radiates out from its source. Energy is present in many forms, most of which do not involve any radiating.

 

Gravitational influence, being due (in Newton's conception of it) to a static field rather than anything in motion, doesn't either. You can draw "field lines" to indicate how the strength of the field varies with distance, just as you can for a magnetic or electric field. These lines, geometrically speaking, diverge from - or, equally, converge towards - the centre of mass. But nothing moves: it is just a field.

 

In Einstein's formulation it is a curvature of space-time, but that too is a static feature.

Lets just exclude the action of gravity from the category of "energy" for a moment here...... What is known as "energy" is radiant any time it doesn't have a logical way to stay sequestered. Even if you compress a spring to turn active energy into inactive energy(kinetic into potential), there is always radiation. Typically its just a small amount of infrared from the spring compressing. Every time you try to store energy in its structure, you have to over-fill it because it will lose some of it. This is true of chemical energy and all other types. Any transfer of it, even ordered transfer, will "lose" some of it in the form of radiant energy. Imagine filling a swimming pool with buckets; no matter how diligent you are about your job, some water will be lost to evaporation. The exact amount lost versus that retained is dependent on the geometry of the pool and how much surface area it has. The power to flow doesn't change, but its ability to do so depends on the details of each configuration. This really helps show how matter and energy are one in the same. If you put enough energy into a spring, that spring gains mass. Take out that energy and the spring loses mass and the energy goes radiant. So maybe we could look at other types of energy as "radiation waiting to happen"? Perhaps by extension, matter is also radiation waiting to happen, so to speak.

 

Anyway, the original point of this thread was really just to identify what sort of clocks had actually been used to test the principal and what sort of insights that each method might actually give us about the concept of "time" itself. I wouldn't argue time dilation is not real, or even that the math of it isn't understood well. I just wanted to know what deeper insights could be gleamed from the various actual experiments that have been done on the matter. The attitudes that presented themselves were truly a distracting force from this goal. I find issues with the twins paradox beyond just the obvious, and I want to understand why.

[exchemist]

Lets just exclude the action of gravity from the category of "energy" for a moment here...... What is known as "energy" is radiant any time it doesn't have a logical way to stay sequestered. Even if you compress a spring to turn active energy into inactive energy(kinetic into potential), there is always radiation. Typically its just a small amount of infrared from the spring compressing. Every time you try to store energy in its structure, you have to over-fill it because it will lose some of it. This is true of chemical energy and all other types. Any transfer of it, even ordered transfer, will "lose" some of it in the form of radiant energy. Imagine filling a swimming pool with buckets; no matter how diligent you are about your job, some water will be lost to evaporation. The exact amount lost versus that retained is dependent on the geometry of the pool and how much surface area it has. The power to flow doesn't change, but its ability to do so depends on the details of each configuration. This really helps show how matter and energy are one in the same. If you put enough energy into a spring, that spring gains mass. Take out that energy and the spring loses mass and the energy goes radiant. So maybe we could look at other types of energy as "radiation waiting to happen"? Perhaps by extension, matter is also radiation waiting to happen, so to speak.

Energy conversion by no means requires any involvement of radiation.In the examples you give, radiation only becomes involved due to inefficiencies in many macroscopic processes, which typically produce heat losses.

 

This incidental inefficiency of many such energy CONVERSION PROCESSES does not in any way justify the idea that all ENERGY ITSELF is radiation. It is not.

 

Electrical energy is not.

Chemical energy is not.

Gravitational Potential energy is not.

Heat energy in matter is not.

Nuclear energy is not.

 

In science one has to think clearly: energy and energy conversion processes are not the same thing.

Edited May 31, 2017 by exchemist

[mrg]

 To be fair, my understanding in this realm is sub-par.

 

JMJ, I would be much more generous and say that it is par, and couldn't be anything else.   The only people who ask questions about the nature of time are theoretical physicists, and it is effectively a conversation among themselves.   We may listen in as a matter of curiosity, but it's like listening to an orchestra when we can't play any musical instruments.  We may like the performance or not, but that's all we can say about it.  We can't tell the orchestra how to do a better job if we don't like it, because we don't know the job.

 

The question of the nature of time is of no practical relevance, and of no relevance to any other field of science.   Everyone knows what time is, we have no trouble with questions like:  "What time is it?"  "When should we meet?"  "How long will it take?"   We all take for absolute fact that it never really flows backwards; we never blow something up but then see it spontaneously re-assemble, we never remember the future. 

 

Einstein did throw us a curve by pointing out that time isn't invariant -- which is something we can grasp, if fitfully, and is useful in certain specialized circumstances.   However, a discussion among layfolk about the nature of time is like a discussion over the meaning of Japanese text -- where none of the people in the discussion can read Japanese.  Somebody who does can tell us what it means, but then we have to take it at that.

Edited May 31, 2017 by mrg

[AmishFighterPilot]

Energy conversion by no means requires any involvement of radiation.In the examples you give, radiation only becomes involved due to inefficiencies in many macroscopic processes, which typically produce heat losses.This incidental inefficiency of many such energy CONVERSION PROCESSES does not in any way justify the idea that all ENERGY ITSELF is radiation. It is not.Electrical energy is not.Chemical energy is not.Gravitational Potential energy is not.Heat energy in matter is not.Nuclear energy is not.In science one has to think clearly: energy and energy conversion processes are not the same thing.

What I am saying is that is that unless it is bound into something, energy radiates, and all energy and matter can become radiation. Heat adds mass, but radiates away as electromagnetic waves(usually IR). Atoms produce vibrational energy(even at absolute zero). Electrical conduction produces magnetic fields, which produce electromagnetic waves and heat radiation.

[AmishFighterPilot]

The big bang is a model for the evolution of our universe, though this process does not describe current events it is true.

 

But what about absorption of radiation by matter? Is that not energy "condensing"? You start with some matter and some radiation. And you end with just matter, the radiation having made the matter a bit heavier, in accordance with your beloved formula.

 

(And if you insist on pure radiation-to-matter conversion, you can look up "pair production".)

Just a few thoughts on pair production. It represents the maximum state of photonic energy being put in direct collision with its twin approaching from the opposite direction. Obviously the particle and anti-particle represent spin, just like how if you have two identical gears on opposite sides of a central gear, the same side of each of the identical gears will be opposite of its twin. So if you were to draw and arbitrary compass over the central gear, the North part of one side gear will always be away from the central gear while the other gear's North side is against it. There's tons of other parallel actions in  physics. What is clear is that it takes something special to hold energy bound as mass. My strong suspicion is that tiny event horizons might provide just what is needed for that. Thing is, when two photons at maximum energy collide, it clearly doesn't have the energy to do this. It would take something very massive. Super massive even.

 

A lot of this makes me think of zero G bubble dynamics: https://youtu.be/cXsvy2tBJlU

[exchemist]

Just a few thoughts on pair production. It represents the maximum state of photonic energy being put in direct collision with its twin approaching from the opposite direction. Obviously the particle and anti-particle represent spin, just like how if you have two identical gears on opposite sides of a central gear, the same side of each of the identical gears will be opposite of its twin. So if you were to draw and arbitrary compass over the central gear, the North part of one side gear will always be away from the central gear while the other gear's North side is against it. There's tons of other parallel actions in  physics. What is clear is that it takes something special to hold energy bound as mass. My strong suspicion is that tiny event horizons might provide just what is needed for that. Thing is, when two photons at maximum energy collide, it clearly doesn't have the energy to do this. It would take something very massive. Super massive even.

 

A lot of this makes me think of zero G bubble dynamics: https://youtu.be/cXsvy2tBJlU

This shows you do not understand E=mc².

 

But I am losing faith that you are interested.

Edited May 31, 2017 by exchemist

[mrg]

But I am losing faith that you are interested.

 

I was tempted to say a few unkindly things myself -- but AFP tends to come unglued when I do that.   Not worth the trouble.