Personal Topic

[marcospolo]

I'm not sure about this, but I think the Galilean transform is all that's needed in Lorentz's "real" world, i.e., the one that emerges when "true" states of motion are calculated.

 

But in that world, the "relativity principle" disintegrates (depending on how you interpret the issue of whether the laws of physics are "the same").

 

In the "apparent world," i.e., the one which is revealed by (inaccurate) measurements, time varies.  Galilean transforms presume that the time in each frame is invariant.  The LT are basically a way to predict how things "appear" to us.

 

In its pure form, the time in LR does not change.  If the ticking rate of a moving clock slows down (which it does) with speed, that can still be explained in terms of the "real" time.

 

For example:  Let's say that I'm on a moving train and that (contrary to the prohibitions of SR) that I conclude that I am moving, not the guy standing by the tracks.  That would imply that my watch has slowed down.  Knowing that it is unreliable, and knowing the LT, I can calculate the "real time."  If I do that, then I, just like the guy standing by the tracks, will agree that two strikes of lightning hitting opposite ends of the train at the same time, were indeed "simultaneous," even though I don't perceive them to be.

 

That may not make much sense, I don't know.  I'm not sure how else to put it.

Ok, here's a challenge for you. The Lorentz transformation derivation always uses light because light speed is invariant. Light has nothing to do with our spaceship or even airplane. Light just provides the constant that remains static for every observer.

So here's the challenge:  Can you derive the same equation that gives the same results as Lorentz, for objects moving at normal human speeds, without employing lightspeed as the constant?

It should be possible as light is only a constant under very specific circumstances, that is in a total vacuum. (physicists don't believe that such a thing exists,, even on deep space, they claim that virtual particles pop into existence, and that must affect light speed) and light is not constant in other mediums, can be slowed, and probably speed up under the right conditions.

 

But on earth, light will go the same speed through glass or water for any observer.  But so will sound waves. They travel through air at a certain speed, in a certain density of air, so we should chose sound waves at sea level as our constant.  Any observer measuring the speed of sound will get the same results, same as Einstein and Lorentz required of light in their derivations.  There is nothing magical about light as a constant compared to the constant of the speed of sound in the development of our equation; Light is a wave and so is sound, they both can be used as "clocks" .

 

And the speed of sound is much closer to speeds that we can actually reach on earth, at sea level. So the results should be more accurate that the 1 divided by billions of the LT equations at low speeds.

 

So two observers measuring the speed of sound, one is sitting on the beach, one is flying past in a glider at 100 mph. The speed of sound is say 760mph.

The moving observer will allow for his own speed of 100mph when he reads his instruments.

 

So can you still derive a working equation by using sound as the "constant" that gives the exact same results as Lorentz did using light? Actually you can't even get any sensible result. Ive tried. You cant use the logic of Lorentz to derive his equations using any other constant than light, and then it only has any noticeable effect if you are going almost light speed. How convenient that we can never prove to ourselves that Lorentz is correct, by driving faster in our car, or observing any measurable object in our world.

 

So please ruin the LT equations in some scenario, but use the speed of sound as the constant. See how far you get. The advantage of a constant is that its unchanged regardless of the other conditions, and in this case, light speed is the constant that provides only the benchmark from which to compare our real speed, as seen by two different observers. So using sound speed should by rights, give the exact same result.

It will not, but I would like to hear your explanation why this does not work.  Does light speed have some magical property that sound speed lacks? Is it a Freemason secret spell placed on light that makes it do the impossible, and we are only talking about the SPEED of light, not light itself.

[Moronium]

Ok, here's a challenge for you.

 

 

That's a very long post, Marco, and I'm not sure I agree with all the premises you seem to employ.  Give me a minute, and I will try to locate a source (from a Harvard Prof. of Physics) that I think "might" be responsive to your question...

[Moronium]

OK, here's an excerpt from the book I was thinking of:

 

Given the second postulate, you might wonder if we even need the first. If all inertial frames are equivalent, shouldn’t the speed of light be the same in any frame? Well, no. For all we know, light might behave like a baseball. A baseball certainly doesn’t have the same speed with respect to different frames, and this doesn’t ruin the equivalence of the frames.

 

It turns out (see Section 11.10) that nearly all of special relativity can be derived by invoking only the second postulate. The first postulate simply fills in the last bit of necessary info by stating that something has the same finite speed in every frame.  It’s actually not important that this thing happens to be light. It could be mashed potatoes or something else

 

 

http://www.people.fas.harvard.edu/~djmorin/chap11.pdf

Edited February 10, 2019 by Moronium

[Moronium]

 

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Ok, here's a challenge for you. The Lorentz transformation derivation always uses light because light speed is invariant. 

 

Again, Lorentz does not say that light IS invariant in every frame, only that it will be measured to be the same.  The LT, although identical in form, is not the same in substance when comparing LR to SR.  So it's not really the same formula.

 

In SR the v (for velocity) in the LT is relative.  In LR it is absolute.

 

You say:  "The Lorentz transformation derivation always uses light because light speed is invariant."  That's only true in SR.

 

Why is it "true" in SR?  Because Einstein SAYS so, that's why.  It's a postulate, damn it.

Edited February 10, 2019 by Moronium

[marcospolo]

And I am not sure I believe that we have accurately measured time on a clock going slower because its moving. The possible differences due to the relatively slow speeds possible, are minuscule, and could be attributed to a number of things. The clocks on the airplanes had to content with speeding up due to less gravity, and slowing down due to motion. but the calculated rates could not really be employed, as the planes, and earth are not in inertial frames, (essential to the LT) and there was always acceleration and deceleration going on.

I doubt that anyone could calculate the exact amount of time dilation expected given the large number of variables and the lack of detailed measurements recorded about the flights.

The detailed measurements on the planes would not have been correct anyway, as the rulers have shrunk.!

 

GPS is a minefield of controversy regarding clocks, so we cant use that as an example.

 

All we really know is that gravity affects physical processes, and seems to also affect the oscillations of the atoms in an atomic clock. (or however they work) So physical processes slow a tiny bit with less gravity, but the guys on the space station , in micro gravity, and all their equipment, for months and years, don't seem any worse for wear.

 

And even if motion upset the processes of physics, the amount of change may not keep getting larger with more speed, it may experience some initial change, then settle out, and not really change that much more regardless of how much faster one goes.  Who knows? We can't test it.

[marcospolo]

OK, here's an excerpt from the book I was thinking of:

 

 

http://www.people.fas.harvard.edu/~djmorin/chap11.pdf

Perfect. So now you can derive an equation using sound speed, (better than potatoes) and show me how you can still get the same results as the LT which uses Light speed.

[Moronium]

And I am not sure I believe that we have accurately measured time on a clock going slower because its moving. 

 

Well, Marco, you seem to be adopting your typical philosophical position of skepticism (which, in its pure form, says knowledge is impossible.

 

Plato believed that "knowledge" could only be called such, when it was absolutely, immutably, and eternally true.  And it had to be known with certainty.

 

So, in effect, he was like the skeptics in this sense.  By those standards, nobody can ever "know" anything, and Plato aknowledged that.

 

But, as a practical matter, we don't require that things be known with absolute certainty in order to call them "true."  If absolute certainty is the criterion for "knowledge," then, obviously, none of us will ever "know" anything.

[marcospolo]

 

.

 

Again, Lorentz does not say that light IS invariant in every frame, only that it will be measured to be the same.  The LT, although identical in form, is not the same in substance when comparing LR to SR.  So it's not really the same formula.

 

In SR the v (for velocity) in the LT is relative.  In LR it is absolute.

 

You say:  "The Lorentz transformation derivation always uses light because light speed is invariant."  That's only true in SR.

 

Why is it "true" in SR?  Because Einstein SAYS so, that's why.  It's a postulate, damn it.

 

Ok, so whats the use of employing the variable "c" with an unknown real value in the LT then?  Because both stationary and moving observer will get different results not only for their own speed, but also for lights speed too. Now we have two experimenters (One moving and the other not) taking independent measurements of unrelated things, using different methods and different units of measurement, that can shrink and expand from time to time, the duration of which is also unknown. The you want to compare their results?  You have just destroyed the only thing that was common to them both. aka, Light speed.  If they cant establish a common agreed set of standards, then they are never going to do any real Physics.

[Moronium]

Perfect. So now you can derive an equation using sound speed, (better than potatoes) and show me how you can still get the same results as the LT which uses Light speed.

 

Heh.  Read the rest of the prof's book.  He's the expert, not me.

 

By the way, where does the LT use "light speed?"  The LT are about time and length transformations.  Granted that you need these to "measure" light speed (or any speed), that does not mean they ARE light speed.

 

As I said earlier, the invariance of light speed is a postulate in SR.  Not so in other theories of relative motion.

Edited February 10, 2019 by Moronium

[marcospolo]

Well, Marco, you seem to be adopting your typical philosophical position of skepticism (which, in its pure form, says knowledge is impossible.

 

Plato believed that "knowledge" could only be called such, when it was absolutely, immutably, and eternally true.  And it had to be known with certainty.

 

So, in effect, he was like the skeptics in this sense.  By those standards, nobody can ever "know" anything, and Plato aknowledged that.

 

But, as a practical matter, we don't require that things be known with absolute certainty in order to call them "true."  If absolute certainty is the criterion for "knowledge," then, obviously, none of us will ever "know" anything.

The slowing of clocks is not a certainty. As its critical to this principal of LT, then we best be absolutely sure about something. Physics cant exist on all assumption and conjecture.

[marcospolo]

Heh.  Read the rest of the prof's book.  He's the expert, not me.

 

By the way, where does the LT use "light speed?"  The LT is about time and distance transformations.  Granted that you need these to "measure" light speed (or any speed), that does not mean they ARE light speed.

They employ light speed in the derivation of the LT equations. Its used as a pretext to jump into the use of Pythagoras theorem, in order to establish the relationship between the two "paths" that light is supposed to be taking, as viewed by each observer. This is of course pure hogwash.

[Moronium]

 The you want to compare their results?  You have just destroyed the only thing that was common to them both. aka, Light speed.  If they cant establish a common agreed set of standards, then they are never going to do any real Physics.

 

I agree with your conclusion here, insofar as it relates to SR.  If SR is going to claim that "everybody" is right, then, in effect, nobody can be right.  Everyone is using different yardsticks and clocks which run at different rates.

 

In LR the speed of light is isotropic in only one frame, i,e,, the preferred frame.  It is that frame which provides the "standard" for time and space (length and distance).  So there is a standard.  Any variance from that standard in other frames is basically "nonstandard" (i.e., not correct)

[Moronium]

For convenience, I'll repost this (post #493) here.

 

One fundamental difference (perhaps THE fundamental difference) between Lorentz and Einstein is this:

 

Lorentz fully realized that one clock running at a different rate than another would give each a different impression of "what time it is."  Each would have his own idiosyncratic "local time" (what Einstein called "proper time").

 

Lorentz considered this "local" time to be a pure mathematical fiction, not the "true" time, but he found the concept useful  as a shortcut for making calculations.

 

Einstein basically took Lorentz's concept of local time, and said that local time was the "true time."

 

 

Does that "explain" anything for you?

Edited February 10, 2019 by Moronium

[Moronium]

The slowing of clocks is not a certainty. As its critical to this principal of LT, then we best be absolutely sure about something. Physics cant exist on all assumption and conjecture.

 

 

Unfortunately all scientific theory (in physics or any other science) can never be proven. It is all hypothetical (based on hypothesis).  It's the human condition--the best we can do.  If you're looking for absolute certainty, then I guess you'll have to talk to God.

Edited February 10, 2019 by Moronium

[Moronium]

Anyone who claims that a given hypothetical scientific postulate has been "proven" is simply trotting out the logical fallacy of "affirming the consequent."

 

It goes kinda like this:

 

1. My theory: If the ground gets wet, then that's because God is upstairs taking a piss (we call it "rain").

 

2.  Looky here!  The ground is wet!

 

3.  That proves that God just took a piss.

 

Edit:  1. should read more like this, actually:

 

If God was upstairs taking a piss, then the ground would get wet.

Edited February 10, 2019 by Moronium

[OceanBreeze]

 

 

The LT math is based on incorrect application of geometric relationships of right angled triangles. 

 

That’s wrong. The Lorentz transform is based on the hyperbolic relationship: cosh^2 – sinh^2 = 1

[OceanBreeze]

Ah, Wikipedia, the source for everything approved by the custodians of truth.

 

Ive looked at it all. I don't agree with any of it.

 

 

It’s no wonder you disagree with it since you don’t understand it.

Edited February 10, 2019 by OceanBreeze