What the heck is Time?

Discussions on classical and modern physics, quantum mechanics, particle physics, thermodynamics, general and special relativity, etc.

Re: What the heck is Time?

Postby Dave_Oblad on February 6th, 2017, 2:59 am 

Hi Folks,

At a time when virtually everyone believed in an Aether, Einstein created SR sans Aether. It didn't work. He couldn't progress further with his Physics using it. He corrected that mistake with GR. And stunned the world with the results.

Please review my quotes at:
http://sciencechatforum.com/viewtopic.php?f=2&t=32255&view=unread#p314905

Robert B. Laughlin called it Ironic. Obviously, he was being very Kind. But if one prefers Relativistic Aether to describe the underlying foundation of Reality, then fine. (Biv) Let's not forget what Ligo has to say about this substance (?) called the Aether. Gravity Waves are not information being processed within the Electro-Magnetic carrier aspects of the Aether, it is a Compression Wave of the Aether fabric itself.

I mean no disrespect to Einstein as he is one of my most revered people from History. His work changed the world. SR is a fine tool for introduction to the fantastic world of Dilation, among other things. But even if I'm a lone voice in the whole world, I believe the way Time is being treated is flat out wrong.. IMHO. Time is being added to the Surface of the Universe as Planck Intervals, that in my book, is still just Distance along the 4th Dimension axis.

https://arxiv.org/pdf/1606.07975

Despite what our clocks tell us, we are all progressing into the Future at the exact same rate.. the Speed of Light. Information cannot move laterally in 3D any faster than New Time-Distance is being added to the 4th Dimensional Surface in the Expansion of the Universe. This is the basic reason why Light Speed is NOT additive to the Velocity of the Source of that Light.

I strongly object to this view: That we give up Velocity through Time in exchange for Velocity through Space. (Our velocity through Time is a Universal Constant, despite what our clocks seem to tell us)

Anyway..

I have a legitimate question (Jorrie?): If Alice and Bob have a absolute differential Velocity of 0.6c then can one predict their Clock Dilation differential?
If not... why?
If so.. then things are about to get real interesting.. lol.

Also.. Curious.. How many folks object to using the Velocity of Light as a Relative Velocity for all other potential Velocities (obviously in Flat Space sans Gravity)?

Note: "Time" is a current hotbed subject that few Academic Experts will agree upon. Few have even offered an explanation for the underlying Mechanics of Time. Given the plethora of Personal Theories regarding Time by the Academic Community, pretty much anything reasonable still goes, as long as it it consistent with observables.

Disclaimer:

Oh.. for all you folks just passing through.. I am not, nor claim to be, an Expert. I'm an Engineer and Programmer. The latter requires extra skills in problem solving and reductionism of complexity. I'm merely exploiting that skill here, searching for a more simple and logical view of Relativity and the Universe in General. So again, just to be perfectly clear, I am NOT an expert nor academic with credentials.. so don't go quoting me. At best, I am just an explorer, looking under all the rocks and behind all the curtains, trying to form a complete picture of our Reality.

Ok.. bedtime for me.. heavy work load coming this week.. I'll try to get back as soon as I can.

Best Regards all,
Dave :^)
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Re: What the heck is Time?

Postby ralfcis on February 6th, 2017, 7:50 am 

" At best, I am just an explorer, looking under all the rocks and behind all the curtains, trying to form a complete picture of our Reality."

I don't see that Dave. Your picture of reality is entrenched in the realm of pop-sci. You're not looking behind the curtain, you're behind the curtain like the wizard of OZ. You don't want to look outside the curtain because when someone points to something outside, you just keep pulling the same magical levers unfazed.
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Re: What the heck is Time?

Postby BurtJordaan on February 6th, 2017, 10:59 am 

Hi Dave,

Apart from the fact that the paper of Prof. Richard Muller is highly speculative and borders on philosophy, it has no bearing on your resistance to SR and GR. It is fully compatible with the modern view and attempts to expand on it. Good luck to him!
Dave_O wrote:If Alice and Bob have a absolute differential Velocity of 0.6c then can one predict their Clock Dilation differential?

"Absolute velocity" is undefinable in the SR/GR context, so as such only a relative speed of 0.6c has any objective existence.

The closest you can come is to say that Alice is moving inertially at 0.6c relative to a cosmological comoving observer[1] and Bob is moving inertially at 0.8c in the same direction, also relative to the same comoving observer. They then have a relative speed of (0.8-0.6)/(1+0.8*0.6) = 0.135c. Each of them will view the others clock to run slow by the usual gamma factor, but here is no "clock differential" between them.

Why? Because they are both simply inertial observers and hence are equal before science. And try as you like, you have no way of proving or demonstrating that this is not true. Literally thousands have tried and failed...

-J

[1] A cosmological comoving observer is one for which the CMB has the same average temperature in all directions.
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Re: Double Time

Postby Faradave on February 6th, 2017, 12:44 pm 

Hi Dave_O,

I've been busy helping with my 91y.o. mother's move to assisted living but still enjoy reading your posts. Granting several interesting similarities in our personal theories, we still have several equally interesting differences.

Dave_Oblad wrote:I strongly object to this view: That we give up Velocity through Time in exchange for Velocity through Space. (Our velocity through Time is a Universal Constant, despite what our clocks seem to tell us)


As you'll recall, I distinguish between future displacement and aging. Future displacement will be equal for all observers, forming the basis of conservation of mass-energy (and all the conservation laws). Conserved quantities are invariant on "time translation", which itself translates (grammatically) to "future displacement".

Aging, by contrast, is time experienced on the way to the future. I believe this effectively implies different available paths (aging and non-aging) for which I employ corresponding coordinates (Times Square). In any given coordinate frame, Proper Time represents the aging path and is paralleled by the worldlines of objects at rest in that frame. Light, on the other hand, takes a geometrically independent path (I refer to as "Improper Time", forming the horizontal coordinate. As such, it is non-aging. Both paths are future directed.

In your expanding 3-sphere model, Proper Time would be normal to the surface (i.e. radial, v0) while Improper Time would be tangential (vmax). Either way, they progress to more outward (i.e. future displaced) layers.

Image

Dave_Oblad wrote: Curious.. How many folks object to using the Velocity of Light as a Relative Velocity for all other potential Velocities

I have often felt that temptation but I'm still among the objectors. Though observers referring to your reference light from different frames all find it to have speed limit c, they also find it to have different energy (i.e. frequency, color). That's how they can know they don't share the same relative speed (i.e. inertial frame).
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Re: What the heck is Time?

Postby hyksos on February 6th, 2017, 4:07 pm 

At a time when virtually everyone believed in an Aether, Einstein created SR sans Aether. It didn't work. He couldn't progress further with his Physics using it. He corrected that mistake with GR. And stunned the world with the results.

This just did not happen in history. You might as well be on a history forum telling people that the Confederate States defeated the Northern Union army in 1879.
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Re: What the heck is Time?

Postby Dave_Oblad on February 6th, 2017, 4:21 pm 

Wow Jorrie,

Your post sure cleared up a lot of misconceptions of mine. Added to this was my brief search for a SR Internet Calculator to see the Equation for co-moving travelers and guess what? I already know how I was going to code for such a problem (Absolute Relativity), by using a stationary observer as a reference (which I had previously thought was forbidden in SR). Turns out this is how everyone does it. (my Method)

Jorrie wrote:A cosmological comoving observer is one for which the CMB has the same average temperature in all directions.

Technically.. this would have been my stationary observer reference.

So the problem I suggested, by convention only, simply splits the difference when the only available information is their Relative Speeds. So when an SR problem states that Bobs Speed, relative to Alice is (X), it is implied that Alice is stationary. Because if Alice is also moving, then we get the same issue I was trying to highlight with the problem I suggested in my previous post.

So, it looks like I was wrong in spitting the difference between Classical and Absolute. All Relativists are in fact, Absolutists. I defined Classical as those that believed that the only data needed was a velocity differential and, in just one post, you smoked my upcoming debate. Bravo and a big Thumbs Up.. :^)

To be clear, I have no objection to Dilated Clocks.. Technically, a burning Match will last longer at Relativistic speeds than a Stationary burning Match. And if Science wants to call that "Time".. then so be it.

So, my definition of Real Time is that which a Stationary Clock would measure.

I still hold that a Universal Time exists and that moving objects do not have Variable Rates through Real Time. Or put another way, all travelers move through the exact same number of Planck Intervals for any given period measured by our Stationary Clock. Thus implying that Dilated Clocks run slower due to mechanical relationships within Matter/Energy/Speed and not Real Time Per Se. That all objects propagate through Real Time at the exact same velocity, which is the Speed of Light. This being the only explanation for why two travelers, with clocks running at different rates, can rejoin each other at some point in their shared future at the same coordinates in Space-Time.

A Mechanical explanation for Clock Dilation would take us into Personal Theories, so I'll stop short of that.

I also discovered that SR is more than just Einsteins two original postulates. That there was a lot of other Math included in SR that allowed Einstein to produce the formula: E=MC2.

There also appears to be on going debate as to whether Einstein was influenced by M & M in trying to eliminate the Aether in SR, but that got corrected in GR by the introduction of a Relativistic Aether he called Space-Time. The reasons for Failure in M & M got cleared up.. and all was well in the world..lol.

I never had an issue with GR, and now that I've more fully researched SR, I have a new respect for it, even if it did try to kill my beloved Aether.. ;^P

My research into Calculations for multiple moving clocks and Jorrie's post has cleared the air and has been highly educational for me. (hopefully for others too)

I still take issue with the concept: "That we give up Velocity through Time in exchange for Velocity through Space." (Ie. We all propagate through Real Time with the same velocity.. light speed)

But I'll save that debate for another Time.. lol.

Best wishes all and special thanks for Jorrie's timely input..
Dave :^)

Ps. Hyksos, Einstein could not produce his Field Equations using SR.. as it had no fixed foundation. GR cleared that up and allowed said Equations to be produced. That's what I've read anyway, but perhaps that Author was wrong?
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Re: What the heck is Time?

Postby hyksos on February 6th, 2017, 4:53 pm 

There also appears to be on going debate as to whether Einstein was influenced by M & M in trying to eliminate the Aether in SR, but that got corrected in GR by the introduction of a Relativistic Aether he called Space-Time. The reasons for Failure in M & M got cleared up.. and all was well in the world..lol.

Ps. Hyksos, Einstein could not produce his Field Equations using SR.. as it had no fixed foundation. GR cleared that up and allowed said Equations to be produced. That's what I've read anyway, but perhaps that Author was wrong?

What the heck author is this? {"Relativistic Aether he called Space-time"} What author would ever write such a senseless phrase?
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Re: What the heck is Time?

Postby TheVat on February 6th, 2017, 5:16 pm 

I don't see what he means by "real time" unless he just means spacetime. Sentences like "...We all propagate through Real Time with the same velocity..." would make more sense, if that were the case. C defines the basic rate at which things happen, the sum of all translational vectors. Therefore, the "giving up v through time in exchange for v through space" is just the basic math.
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Re: What the heck is Time?

Postby Dave_Oblad on February 6th, 2017, 5:19 pm 

Hi Hyksos,

I read somewhere that SR failed to provide the necessary foundation needed for the Field Equations in GR. I adopted the view probably due to Confirmation Bias. It made sense. Whether True or not, I don't honestly know. There is also the possibility that I have reworded the statement and lost its original meaning. Since I can't supply a link to such a Statement or Author, I will withdraw that statement.

We do know that Robert B. Laughlin called Space-Time a Relativistic Aether but also declared such a comparative term is Taboo.. due to the negative connotations of an Aether prevalent in the Physics community.

Is Space-Time a Relativistic Aether? Perhaps Jorrie will chime in on this with his opinion, as I'm curious also.

Best Regards,
Dave :^)
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Re: What the heck is Time?

Postby Dave_Oblad on February 6th, 2017, 5:53 pm 

Hi Biv,

I argue that any differential Velocity must create a separation in Time or Space. Since two travelers with different clock dilation's can rejoin later at the same Space-Time coordinate, then there was no Temporal Velocity difference between them.

Ie. On an infinite plane with two travelers at different Velocities, then separation will exist/grow and can never be corrected unless one of them changes their velocity to re-unite them.

I see the same issue with the plane represented as a Temporal Plane. I see "Time" as Literal Distance. That there exists a Literal Distance between Today at Noon and Tomorrow at Noon. This is a 4 Dimensional Viewpoint, that I believe is fairly common in Physics and Quantum Mechanics. Also, related to the Expanding Block Model and even the end of Brian Green's Video with this example:

BlockModel.jpg
Time as mapped from left to right

I see the bottom scale as a true literal distance from the BB to Now (in 4D of course).

Regards,
Dave :^)

Ps. Later.. Must get back to work.. deadlines are killing me.. lol.
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Re: What the heck is Time?

Postby Inchworm on February 6th, 2017, 6:49 pm 

Dave, if I understand you well, you mean that the real distance traveled by light in the light clock mind experiment would really slow down the clock. I agree with you that, if the clock is really traveling, then light has to be aimed the way it is shown on the diagram, but I have a problem with the time it would take to reach the mirrors, compared to the time it would take if the mirrors would not be traveling. Sr means that the clocks would record that difference, so that we could observe it if we could reunite the two clocks, but how could they since the only way to record it would be to measure light's frequency, and that light's frequency do not change when bodies are at rest from one another?
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Re: What the heck is Time?

Postby Dave_Oblad on February 6th, 2017, 11:27 pm 

Hi Inchworm,

Huh?

My only mention of Mirrors in this thread was the standard explanation for two-way speed of light measurement. See device below:

TwoWay.jpg
Device to measure Light Speed

The black rod holds everything together.
The Instrument creates a flash at the lamp.
The beam goes through the lower sensor(B) and starts the timer.
The beam goes to the mirror and bounces back to upper sensor(A).
The beam hitting the upper sensor stops the timer and displays the lapse time.

Knowing the round trip distance and travel time, you calculate the Speed of Light.

The lapse time is a constant because it measures the round trip time.

If the device is moving in the direction of the mirror, then the beam is chasing the mirror and travels a greater distance. But the return trip is shorter because the upper sensor is coming to meet the beam. The round trip is a constant, even when the device is in motion.

Anyway, that's the basics and you probably already knew all this, so the effort is mostly for any Beginner Audience. (which probably includes me.. lol)

If this wasn't what you were asking about, could you be a bit more clear?

I'm calling it a day.. a long hard one at that.. back tomorrow.

Regards,
Dave :^)
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Re: What the heck is Time?

Postby BurtJordaan on February 7th, 2017, 2:13 am 

Hi Dave,
Dave_Oblad » 06 Feb 2017, 22:21 wrote:Your post sure cleared up a lot of misconceptions of mine. Added to this was my brief search for a SR Internet Calculator to see the Equation for co-moving travelers and guess what? I already know how I was going to code for such a problem (Absolute Relativity), by using a stationary observer as a reference (which I had previously thought was forbidden in SR). Turns out this is how everyone does it. (my Method)

SR always allows any inertial frame as the reference and since all comoving observes are inertial, the frame of any one is allowed. Just be careful that all comoving observers are not in the same inertial frame, unless they are all so close together that the spacetime curvature due to expansion is negligible.

But, and this is a clincher: they are not necessarily the observers with the slowest clocks in the universe. No other inertial observer, "born in motion" relative to his local comoving observer, can be distinguished from a comoving observer purely by reading their clocks. That is unless one makes some turn and passes the other observer again, because then we have the classical (non-paradoxical) 'twin-paradox'.

This is because uniform relative motion does not change clock rates - all inertial observers are still born equal in the eyes of physics. Whoever wants to use the CMB (and the comoving observers defined relative to it) as the "absolute frame" with "absolute time", "absolute space", etc. is doomed to be eventually cast into the nutty cage.
There is no "relativistic aether"; spacetime is spacetime and has properties far removed from anything that could be called an aether.

Finally, the notion that time is the same as space (or "just another spatial dimension") is a dangerous falsehood. In spacetime mathematics and spacetime diagrams we often use the quantity ct, because it "puts time on the same footing as space", but it does not convert time into space. Things have speed and momentum through space, but never through time. To talk about the speed of time is just a metaphor, not science. Ditto for saying that we "travel at the speed of light in the time direction". The way we formulate or picture physics in order to analyze it should not be confused with the underlying physics.

Some confusion may have arisen from physicists talking about 4-space, 4-momentum and 4-velocity in spacetime, but the 4th component is not plain old time - it is just a mathematical construct that we find useful when solving tough problems. The 4-vector does not depict the worldline of an object in standard spacetime.
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Re: What the heck is Time?

Postby Dave_Oblad on February 7th, 2017, 4:14 am 

Hi Jorrie,

Jorrie wrote:SR always allows any inertial frame as the reference and since all comoving observes are inertial, the frame of any one is allowed. Just be careful that all comoving observers are not in the same inertial frame, unless they are all so close together that the spacetime curvature due to expansion is negligible.

Now I am confused. Your previous post just said that, without a stationary reference, then only knowing the differential velocity between two travelers is insufficient information to compute their relative clock dilation's and thus, by convention only, you split the difference.. which of course is silly and not reality.. but I don't care.

Now you say (quoted above) any frame is allowed as the reference. Are you now excluding the knowledge that at least one traveler has an Absolute Known Velocity or is Stationary? If not, we are right back to this silly split the difference thing that obviously can't represent Reality.

For example, if all we know is that Bob is 25% of c faster than Alice, then you will get differing Dilation Factors depending on which end of the Lorentz Scale we place Alice. The solution to such has an almost infinite number of potential solutions because the Lorentz Equation is Non-Linear.

Can you clear this up? We must know the Absolute Velocity of at least one reference frame or it all falls apart.. Obviously.

Note: Stationary or 0.2c (etc) are Absolutes when applied to any single Frame-Traveler.

Regards,
Dave :^)
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Re: What the heck is Time?

Postby BurtJordaan on February 7th, 2017, 5:20 am 

Dave, there you have just said it all - 'absolute relativity' falls apart at the seams and is not revivable. ;)

Dave_Oblad » 07 Feb 2017, 10:14 wrote:Can you clear this up? We must know the Absolute Velocity of at least one reference frame or it all falls apart.. Obviously.


This makes relativitists very, very happy, because we do not care about (unknowable) absolute frames, speeds, distances, etc. With your absolute frame mindset, it is somewhat understandable that you seem to be incapable of taking in what we relativists write.

I wrote: "The closest you can come is to say that Alice is moving inertially at 0.6c relative to a cosmological comoving observer[1] and Bob is moving inertially at 0.8c in the same direction, also relative to the same comoving observer. They then have a relative speed of (0.8-0.6)/(1+0.8*0.6) = 0.135c. Each of them will view the others clock to run slow by the usual gamma factor, but here is no "clock differential" between them".

What made you to see some absolute speed in there? I did clearly state that comoving observer represents just another (local) inertial reference frame and A and B have speeds relative to it. Plain, standard relativity, what else?

OK, maybe it is my using your term "clock differential". It was sloppy - the meaning I had in mind was difference in elapsed time, which can only be unequivocally obtained by two clocks in relative motion, if they pass each other at least twice.[1]

Time dilation, on the other hand, is a term used for the reciprocal observation that the other parties clock runs slow, but since it is reciprocal, it has no bearing on elapsed times. It may however be confused with terms like "clock differential". We should avoid that term and stick to the standard, well defines terms.

-J

[1] The method of just bringing Bob to rest in Alice's reference frame and then comparing Bob's elapsed time with the elapsed time in Alice's frame, is workable, but full of opportunities for misinterpretation. The direct comparison has no such problems. This is absolute! ;)

PS.
Dave_O wrote:Note: Stationary or 0.2c (etc) are Absolutes when applied to any single Frame-Traveler.

Another confusing Absolutism. There is no thing like a "single Frame-Traveler". If you are free-floating in free space, you can set up only one inertial frame in which you stationary. You can also set up only one other inertial frame in which you are traveling at 0.2c in a certain direction. But you can also set up a zillion different inertial frames in which you are traveling at other speeds. We are all "multi-frame-travelers".
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Re: What the heck is Time?

Postby Dave_Oblad on February 7th, 2017, 9:34 am 

Hi Jorrie,

Let's see if you are correct:

Alice has speed (X) and Bob is 0.25c faster than Alice.
What is the dilation factor for Alice?
What is the dilation factor for Bob?
There, you have no reference other than their speed relative to each other.
Can this problem be solved with a realistic answer? (no silly splitting the difference)

Please, just answer this very simple question without forcing an absolute on Alice or Bob. Feel free to shove in as many additional observers as you wish, as long as none of them have an absolute reference.

By absolute reference, I mean stating some party is stationary or has an absolute speed like 0.5c.

Regards,
Dave :^)
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Re: What the heck is Time?

Postby Inchworm on February 7th, 2017, 9:35 am 

Dave-Oblad wrote:Huh?

My only mention of Mirrors in this thread was the standard explanation for two-way speed of light measurement.
The light clock was an example of mine, and my reasoning was about your introduction of an aether. I just wanted to check if we were both tuning the same channel. If there is an aether, then the direction light takes in the light clock is real, it doesn't depend on reference frames. Between two planes moving side by side, the sound they make has to be directed towards the future position of the planes to reach them, and it doesn't depend on an observer situated on the ground.
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Re: What the heck is Time?

Postby Dave_Oblad on February 7th, 2017, 10:12 am 

Hi Inchworm,

I was in an SR debate and I got bumped to Personal Theories. But I was persistent to solve an apparent paradox. On this journey, I accidentally discovered what Frames are all about (more or less).
I think this is related to your question:
http://sciencechatforum.com/viewtopic.php?f=39&t=29384&start=60#p287416

This link above takes you into the middle of the debate, where all the issues get resolved to everyone's satisfaction. And I came away with a better mechanical understanding of how Frames work.

Regards,
Dave :^)
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Re: What the heck is Time?

Postby BurtJordaan on February 7th, 2017, 11:13 am 

Hi Dave,
Dave_Oblad » 07 Feb 2017, 15:34 wrote:Can this problem be solved with a realistic answer? (no silly splitting the difference)

Yes, but there are a zillion different answers, because X can be anything between -c and +c.
There is no thing like a "dilation factor for Alice". Neither can there be for Bob. In your stated problem, there is only a (reciprocal) relative time dilation factor between Alice and Bob.

Seriously Dave, if you are still battling with the fact that there exist no absolute frame or absolute movement, I think there is no hope of convincing you.
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Re: What the heck is Time?

Postby Inchworm on February 7th, 2017, 12:41 pm 

Dave_Oblad wrote:I was in an SR debate and I got bumped to Personal Theories. But I was persistent to solve an apparent paradox. On this journey, I accidentally discovered what Frames are all about (more or less).
I think this is related to your question:
http://sciencechatforum.com/viewtopic.p ... 60#p287416
Have a look at the end of this thread Dave. I was actually trying to interest you to my reasoning, but you went out to answer a phone call and never came back. :0)
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Re: What the heck is Time?

Postby Dave_Oblad on February 7th, 2017, 10:11 pm 

Hi all,

Jorrie wrote:Yes, but there are a zillion different answers

That says it all ;)

The Lorentz Equation doesn't concern itself with multiple observers. It states each Traveler is an Island and its Absolute Clock Rate is totally dependent on its Absolute Velocity relative to Light Speed. Clocks don't care what other Clocks are doing. The correct answer to any Relativity Problem requires the introduction of at least one Absolute, whether Implied or Stated. Only then can an honest answer/prediction/calculation be produced regarding differential clock rates as observed between moving observers.

If the Lorentz Equation was Linear, I would have no foundation to base my argument on. Only if the Lorentz Equation was Linear could one accurately compute clock rate differentials knowing just their relative velocity differentials. (in flat space sans gravity of course)

Thanks Jorrie, your honesty is refreshing.

Inchworm:
(yes, that was a very long call.. lol)

I'm sorry I dropped the ball on that other thread a year ago.. I put a current response there if you want to read it and continue. Again, I'm in a bit of job related overload. We have very important customers on hold until I complete 2 more projects. The current project is 95% complete and the last.. I can't predict.. it's a monster in the area of Math, which is not my strongest Field.

Nowadays I can barely write 20 lines of code without introducing at least one error. I'm almost pooped out.. brain wise. I can't maintain the extreme level of focus required for programming anymore. I easily get lost in the complexity of my own algorithms. It sucks big time!

Highest regards all,
Dave :^)
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Re: What the heck is Time?

Postby BurtJordaan on February 8th, 2017, 1:39 am 

Dave, please constrain yourself from writing scientific nonsense in the physics section, e.g.
Dave_Oblad » 08 Feb 2017, 04:11 wrote:
The Lorentz Equation doesn't concern itself with multiple observers. It states each Traveler is an Island and its Absolute Clock Rate is totally dependent on its Absolute Velocity relative to Light Speed.

On the contrary, the Lorentz transformation concerns itself only with the relative velocity between two frames. It transforms coordinate times and distances between two inertial frames in relative motion.
And the speed of light is c in every inertial frame.

If the Lorentz Equation was Linear, I would have no foundation to base my argument on. Only if the Lorentz Equation was Linear could one accurately compute clock rate differentials knowing just their relative velocity differentials.

I have computed the relative (reciprocal) time dilation when only a relative speed between two clocks is known, multiple times on this forum. Sure, I have never computed an 'absolute time' dilation, because such thing does not exist. I have also computed differential elapsed times between two clocks many times here.

Dave, with your status and with authoritative-sounding, but (sadly) false statements like the above two, this thread is now a candidate for demotion to the Personals section.

With the workload that you have, maybe you should take time off here and concentrate on your programming for a while. Or start a thread in Personals, where you can write more freely and not get hammered so much for correctness...

;-) Jorrie
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Re: Separate Reality

Postby Faradave on February 8th, 2017, 3:22 am 

Hi Jorrie,

- Optional Aside -

Jorrie wrote:Finally, the notion that time is the same as space (or "just another spatial dimension") is a dangerous falsehood. In spacetime mathematics and spacetime diagrams we often use the quantity ct, because it "puts time on the same footing as space", but it does not convert time into space. Things have speed and momentum through space, but never through time. To talk about the speed of time is just a metaphor, not science. Ditto for saying that we "travel at the speed of light in the time direction". The way we formulate or picture physics in order to analyze it should not be confused with the underlying physics.

Some confusion may have arisen from physicists talking about 4-space, 4-momentum and 4-velocity in spacetime, but the 4th component is not plain old time - it is just a mathematical construct that we find useful when solving tough problems. The 4-vector does not depict the worldline of an object in standard spacetime.

At first, I was tempted to object in some way but after a day's reflection and a couple of re-reads, I have to say the above is carefully worded and well worth remembering.

What was bothering me was a sense that we presume time is the "odd ball" dimension, while space provides three "normal" ones. I think Minkowski did a good job avoiding any such bias in his admonition:

"Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality."

Essentially, he advises four dimensions of "spacetime". Nevertheless, even in Minkowski diagrams, spacetime events are specified by four coordinates (relative to a convenient but arbitrary "origin"), typically in a (+++–) fashion, indicating three of space and one of time.

My feeling is that a "dimension" must be defined before the suitability of space, time or spacetime can be evaluated. While "the notion that time is the same as space (or 'just another spatial dimension')" seems correct, it risks presumption. Unfortunately, dimension tends to be defined abstractly. To me, it physically represents the potential for separation. In the most intuitive (i.e. Euclidean) sense, the number of coordinates needed to specify an event represents the number of geometrically independent ways that event can be separate from the origin.

Though Minkowski spacetime is non-Euclidean, its events are specified by 4 coordinates, suggesting that both space and time qualify as dimensions. That leaves us with qualitative differences. The conservation laws assure that future displacement is inescapable. By contrast, spatial displacement is optional. However it's worse than that. For any objects spatial simultaneity, that space is completely inaccessible (except for the space occupied by that object). Such access would require instantaneous translation, violating speed limit c. For that reason, I favor time as the more tangible dimension.
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Re: What the heck is Time?

Postby Dave_Oblad on February 8th, 2017, 3:27 am 

Hi Jorrie,

Thanks.. I wanted to extricate myself from this thread many posts ago and said so. It already deviated from the OP in defining the true nature of Time. Nobody has that answer yet.. just a lot of ideas. One of my traits is to be very persistent.. needed for the kind of work I do. It's nearly impossible for me to back away from a problem. I know that annoys some people. I also never back down from a good debate, unless it becomes silly.

So, with that said, I really need to get back to work. I have no problem if you lock this thread, as I already suggested several posts ago. I knew where this would lead and I really didn't want to go there. I never had a problem with GR and now I have a new respect for SR, so I gained something from this Exercise.

Thanks so much for your inputs, it's always a pleasure.

I'll still be ghosting this site and maybe interact a bit.. but I have to get my full focus back on track with my job, if I ever want to retire.

Then.. I'll be available full time to annoy everyone ;^P

Oh.. Hi Faradave.. we cross posted.. Take it away.. I'm done here.

Best Regards all,
Dave :^)
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Re: What the heck is Time?

Postby ralfcis on February 8th, 2017, 5:57 am 

Jorrie wrote:

"Each of them will view the others clock to run slow by the usual gamma factor, but here is no "clock differential" between them".

I'm sorry, I'm trying to rack my brains into coming up with some experiment that will allow each to view the other's clock running slow even in retrospect. As soon as the clocks are relatively stopped you're comparing relative aging. I see no possibility of being able to detect reciprocal time dilation because the speed of light delay prevents that comparison from being made. Any clock comparison that is calculated in retrospect between two inertial frames will yield the result that the clocks were identical, not reciprocally time dilated. But maybe I'm wrong.
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Re: What the heck is Time?

Postby ralfcis on February 8th, 2017, 6:20 am 

Dave,
Does your farewell indicate I'll be seeing Trump's tax returns before I get an answer to my question? I don't even need an exact result, just ball park it for me based on your understanding of relative velocity. Or maybe not.
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Re: What the heck is Time?

Postby BurtJordaan on February 8th, 2017, 8:19 am 

ralfcis » 08 Feb 2017, 11:57 wrote:I'm trying to rack my brains into coming up with some experiment that will allow each to view the other's clock running slow even in retrospect.


There is an extremely easy experiment to measure reciprocal time dilation directly (and we have discussed it before). Alice and Bob's spaceships are each equipped with an extremely accurate frequency source/transmitter and a frequency measuring receiver/recorder. They now approach each other at a constant 0.6c relative speed, but so that they narrowly avoid a collision.

We expect that the relativistic Doppler ratio will be 2, i.e. each will 'see' the others standard transmitted signal as having double the standard frequency (as we have discussed before). Once they have passed each other, we expect that the received frequencies will be half of the standard transmitted frequency.

This scenario can only happen if the clocks are reciprocally time dilated as relativity requires. If we had an absolute frame for light, Alice and Bob would not have received identical Doppler-shifted signal on either side of the flyby.

I doubt if this exact test has ever been done, but it is proven every time we receive the radio signal from a fast-moving spacecraft. A special test is totally superfluous and a waste of money. It was also indirectly tested in the Vessot Rocket Clock Experiment.
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Re: What the heck is Time?

Postby ralfcis on February 8th, 2017, 9:38 am 

Bob and Alice are unaware of what the other is seeing and the speed of light delay between them makes that info unavailable. Hence, they can't see whether they're dilating wrt each other or not. All Alice and Bob know is that their relative velocity is .6c approaching or .6c leaving based on the doppler ratio. They can certainly calculate their reciprocal time dilation based on their relative velocity but they can't measure it.

At the transition between +.6c and -.6c, they are neither approaching or leaving which means for a split second their relative velocity is zero. Being in the same inertial frame and not separated by the speed of light delay makes this an example of relative aging, not reciprocal time dilation. There isn't even any relative aging going on between them to even hint that their clocks were mutually dilating. Even if you analyzed this example having occurred in the past, at no time could you compare their clocks and see they were not reading the same time.

A further proof of this is if they started their journey equidistant from the earth. If their relative velocity was .6c head on, they'd each be going .33c relative to the earth. (I think this is Dave's confused understanding of an absolute relativity to a fixed background.) They would each age .943 yr per earth year per ly they traveled to earth. This means they couldn't have aged relative to each other even though their relative velocity was .6c.

I was expecting you to invoke the muon example. But that again is an example of relative aging, not reciprocal time dilation. The half-life of the muon is the muon's clock. When the muon self-destructs or hits the earth, the clock stops and it's relative velocity to the earth is zero. The muon ages relatively slower than the earth ages for the time it travels from the upper atmosphere until it stops. There is no reciprocal time dilation if relative aging is occurring. The 2 are mutually exclusive.

So is there some experimental proof that reciprocal time dilation is measurable and hence real?
Last edited by ralfcis on February 8th, 2017, 10:01 am, edited 1 time in total.
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Re: What the heck is Time?

Postby BurtJordaan on February 8th, 2017, 10:00 am 

ralfcis » 08 Feb 2017, 15:38 wrote:Bob and Alice are unaware of what the other is seeing and the speed of light delay between them makes that info unavailable. Hence, they can't see whether they're dilating wrt each other or not.

This IS an example of direct measurement of reciprocal relative time dilation. Bob and Alice can communicate virtually instantaneously as they pass each other and confirm that they each have observed a 2:1 Doppler ratio all the way, except at the flyby. They can also communicate later and confirm that they each have measured a 0.5 Doppler ratio after the flyby.

Only reciprocal relativistic time dilation (or reciprocal wavelength contraction) can explain their measurements. What more reciprocal can you ask for?

And there is never any differential aging going on...

PS: there are other methods, but they involve a grid with clocks for each of them and more difficult to explain.
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Re: What the heck is Time?

Postby Inchworm on February 8th, 2017, 10:08 am 

Burt wrote:This scenario can only happen if the clocks are reciprocally time dilated as relativity requires. If we had an absolute frame for light, Alice and Bob would not have received identical Doppler-shifted signal on either side of the flyby.
Why not? Put your two ships in air one behind the other, move them both with regard to air in the same direction and at the same speed, and you will get no doppler effect between them. Now move the rear one towards the other the way you described, and you will get the same effect than with light: if you can't feel the air going by and you can only measure sound, you won't be able to tell that you are moving relative to it. Isn't that what Michelson/Morley discovered anyway?
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