Simultaneity of event in different frames

[md65536]

Your diagrams show the wave front from the front strike hitting first the moving observer, then the stationary observer, then the position of the rear strike. This is not the information given at the start. The information was that the wave fronts of two similtaneous strikes, from the vantage point of the standing observer, reach the standing observer similtaneously. The moving observer, not being blind, will experience both wavefronts arriving at that point, because, at that point, he is halfway between, exactly as the standing observer.

Are you saying that the animations are wrong, because they incorrectly show what special relativity predicts? Or that the animations are wrong, because what SR predicts is wrong? Or that you don't understand the animations?

 

Are you trying to understand how relativity works by studying these examples? Or are you trying to show that relativity is wrong, based on what you already know?

 

 

 

 

Or... are you saying that the animations don't show the original example that was given? If the example is set up so that the observer on the train and the observer on the ground both see the lightning strikes simultaneously, then the observers must pass at that moment, for example if the observer on the train is moved back toward the rear of the train. The observer on the train still measures that the front lightning strike occurred earlier than the rear one (as the front one is farther away and light from it took longer to arrive), and the observer on the ground measures them as simultaneous (as they are equidistant). It's the same result regardless of observer position, even if "what is seen" is changed.

Edited September 16, 2013 by md65536

[tar]

md65536,

 

I am not sure what I am saying. I know the equations of relativity "work", and certainly predictions can be made and things figured based on it. But there are assumptions made, and conventions accepted that just don't make sense to me, when I try to visualize the thing. It is likely that if I "understood" what was being said, and the definitions of "proper time" and so on, I might "get" what is meant by length contraction and the like, but as it stands, it just doesn't seem to add up to me.

 

But that is just me. I used to argue with my calculus teachers about limits and integrals and such because certain aspects of the thing just seemed to me to arrive at approximations, and not reflect reality as closely as I would have liked to see it depicted. Close enough for government work, I guess.

 

Anyway, I just wonder if there is "another" way to look at the situation of light and time and distance that also "works", but does not require length contraction and time dilation.

 

When I look at the recent diagrams of the two expanding circles, NOT touching each other at the moment that the standing observer and the moving observer are both at the same spot, I figure something is being depicted incorrectly. That's all. The implications of whether that means I just don't get it, or someone else just doesn't get it, or I don't know the definitions, or the definitions are incomplete, or what, is sort of my question.

 

Often the term is used, that the speed of light is alway "measured" at C, whatever frame an observer happens to be in. A measurement, implies to me a "schema", a story, that links a series of events, as well as implies a switch between subjective "sensing" or observing, and theoretical "figuring" what the observation is telling one about objective reality.

 

The implications of relativity require curved space, length contraction, time dilation, time moving backward, and all sorts of things that just don't seem to fit together right. It seems much more likely to me, that we see the world exactly right, and our equations fit it, than to imagine that we are seeing it all wrong, and it must fit our equations.

 

Regards, TAR2

[md65536]

Anyway, I just wonder if there is "another" way to look at the situation of light and time and distance that also "works", but does not require length contraction and time dilation.

Yes there is. Remove relative motion from the picture, and have all observers share an inertial frame. Then you can work out the timing of light signals without worrying about relativistic effects. Different observers "see" different orders of events just due to delay of light.

 

If you add in relative motion of observers, and keep invariance of speed of light, you'll have to deal with length contraction and time dilation and relativity of simultaneity.

 

The implications of relativity require curved space, length contraction, time dilation, time moving backward, and all sorts of things that just don't seem to fit together right. It seems much more likely to me, that we see the world exactly right, and our equations fit it, than to imagine that we are seeing it all wrong, and it must fit our equations.

Countless (2+) threads seem to have the same pattern here. They start off with "Help me to understand relativity here" and after other people's explanations, turn to "Nevermind the explanation, I don't think relativity is right."

 

I share the desire to figure this out on your own terms, using your own reasoning. However, I also know that it all becomes simpler after learning what other people have figured out about it, and the tools (proper time, definition of "event" etc) make it a lot easier to think about all this. Then, you don't have to fumble with concepts like becoming "unattached from the rest of the universe". I know because I've been there, trying to work with similar thinking. It is possible to figure this all out on your own terms, and retrace the discoveries of Einstein and Minkowski etc on your own, but it is easier to use their work and learn what SR says, before questioning what it means and whether it's right.

 

By the way, I've looked at this from the perspective of "seeing the world exactly right" and it works, and I've come to the conclusion that special relativity is right, including time dilation and length contraction. Relativistic Doppler analysis might be what you want to look into, and should help with figuring out what the various observers see, consistent with relativistic effects.

Edited September 17, 2013 by md65536

[tar]

md65536,

 

Well thank you for being gentle.

 

I consider myself like the other "nay" sayers. In fact I know I am like them, in the sense that I would like to think that I am figuring something out for the first time. But since we both know that this has already been thought about, by minds with a great deal more horsepower than TAR, and has already been "figured out" quite nicely, my "questioning" takes on a different mood than the fellow who "knows" he is seeing it right, and all the other investigators have gotten it wrong. So I am glad you didn't completely lump me in with that sort.

 

I just enjoy taking it one step at a time, and doing it my way. Its important to me, that I see it. It does not really do me any good to consider that someone else already sees it. Like the child perhaps, who will not keep their hands off the stove because Mom told him it was hot, but will have no trouble keeping his hands off the stove once he is burned. I need to see it for myself. And I am holding out hope, that there is more than one way to look at dilation, that does not require someone else's way of looking at it to be wrong, for my way of looking at it to be right.

 

My conception is that every event in the universe is occuring now, each position in the universe being the "intersection" of past events from everywhere else in the universe. An observer is like a focal point, that is a particular distance at a particular vector terminating at that point, from every other position in the universe. Thus every photon or impulse coming in to a particular point is from a past event, since each point is separated by the speed of light, from every other point.

 

And this fits nicely with the same inertial frame concept, with no motion.

 

Once something moves within this frame work, that focal point moves, but the incoming impulses still travel at the speed of light, and every distance between points remains the distance it takes light to travel it. The only two things moving toward an impulse would change is the frequency of that impulse, and the distance between the focal point and the source of the impulse. If the focal point starts at A and moves to B, the distance between A and B is not changed. But the distance between the focal point and A increases and the distance between the focal point and B decreases. When the focal point reaches B, B as a focal point experiencing the present, and the traveling focal point now very close in distance are sharing the present moment of the universal now, and focal point A is now the distant point. A is still sending out impulses and still receiving impulses in the same manner as when the moving focal point left it, but is now, for the moving focal point, as distant as B was, when it left A.

 

It seems to me, that the whole concept works, once you assign currentness to every point in the universe, and concede that the rest of the universe is the speed of light away from any given focal point.

 

Regards, TAR2

[md65536]

I just enjoy taking it one step at a time, and doing it my way. Its important to me, that I see it. It does not really do me any good to consider that someone else already sees it. Like the child perhaps, who will not keep their hands off the stove because Mom told him it was hot, but will have no trouble keeping his hands off the stove once he is burned. I need to see it for myself. And I am holding out hope, that there is more than one way to look at dilation, that does not require someone else's way of looking at it to be wrong, for my way of looking at it to be right.

Two ways I can think of to take this one step at a time:

 

Work forwards. Don't start with the unintuitive conclusions of SR, as with the animation examples. Instead start with the postulates of relativity. Take small steps figuring out what they mean, and accepting that they are consistent with reality. Then take steps toward understanding the logical consequences.

 

Or work backwards. First accept that SR works in theory, even if you don't think it matches reality. Take an in-depth look at an example, and figure out how "what observers see" fits, according to SR. When you see that every example you try fits, it's easier to accept that SR is mathematically consistent, and then easier to accept that it is consistent with reality.

 

 

On the other hand, taking small steps in trying to understand an example of SR while also denying time dilation etc, is like trying to take small steps through a brick wall.

[tar]

Thanks for the tips. But I have already tried and failed to grasp the "import" of time dilation. You say it is forced by the equations. That I must accept a counter intuitive thing to explain the intuitive. I would rather just wait for a better explanation.

[tar]

md65536,

 

Took a little Wiki tour of the postulates of SR.

 

Understand your point somewhat, but retain my skepticism.

 

My attitude perhaps is best alluded to by a quote I ran into, in an excerpt from a letter Einstein wrote to Italian Mathematician Marcel Grossmann.

 

"I admire the elegance of your method of computation; it must be nice to ride through these fields upon the horse of true mathematics while the like of us have to make our way laboriously on foot.

—Albert Einstein, The Italian Mathematicians of Relativity[8]

"

 

Regards, TAR2

 

Besides, what could s squared is less than 0 possibly mean?

Or setting c to 1 to make the calculations simpler?

Why not just set everything to 1, and we can leave it at that? And have some pie together.

Edited September 19, 2013 by tar

[md65536]

Took a little Wiki tour of the postulates of SR.

 

Understand your point somewhat, but retain my skepticism.

 

My attitude perhaps is best alluded to by a quote I ran into, in an excerpt from a letter Einstein wrote to Italian Mathematician Marcel Grossmann.

Keep at it!, and the skepticism should be replaced by understanding, at least gradually.

 

Hopefully the science resonates with you too, not just the quotes.

[tar]

Sounds good to me.

[DimaMazin]

Yes there is. Remove relative motion from the picture, and have all observers share an inertial frame. Then you can work out the timing of light signals without worrying about relativistic effects. Different observers "see" different orders of events just due to delay of light.

 

If you add in relative motion of observers, and keep invariance of speed of light, you'll have to deal with length contraction and time dilation and relativity of simultaneity.

 

Countless (2+) threads seem to have the same pattern here. They start off with "Help me to understand relativity here" and after other people's explanations, turn to "Nevermind the explanation, I don't think relativity is right."

 

I share the desire to figure this out on your own terms, using your own reasoning. However, I also know that it all becomes simpler after learning what other people have figured out about it, and the tools (proper time, definition of "event" etc) make it a lot easier to think about all this. Then, you don't have to fumble with concepts like becoming "unattached from the rest of the universe". I know because I've been there, trying to work with similar thinking. It is possible to figure this all out on your own terms, and retrace the discoveries of Einstein and Minkowski etc on your own, but it is easier to use their work and learn what SR says, before questioning what it means and whether it's right.

 

 

I do make math of indication of clock in two frames.Einstein and Minkowski can't make any math of indication of clock in two frames.Your advertising of their nonsense is inappropriate here.

[tar]

DimaMazin,

 

I don't understand math real well anymore, but the equations you posit, and then redo don't seem to me to have anything behind them. I might not know the meaning of a Japanese phase, but I can recognize when somebody makes some squiggles, as if they are Kanji characters, and they are just nonsense squiggles, and NOT Kanji. I don't even look for any meaning in your equations, because they don't smell right, to begin with.

 

At least with real equations I know there is a meaning behind, that I just don't know enough to grasp.

 

I think your equations don't qualify as having meaning behind. So I don't think you have any basis for degrading the math of Einstein and Minkowski. I am fairly sure your math falls very short of theirs.

 

Regards, TAR2

[DimaMazin]

DimaMazin,

 

I don't understand math real well anymore, but the equations you posit, and then redo don't seem to me to have anything behind them. I might not know the meaning of a Japanese phase, but I can recognize when somebody makes some squiggles, as if they are Kanji characters, and they are just nonsense squiggles, and NOT Kanji. I don't even look for any meaning in your equations, because they don't smell right, to begin with.

 

At least with real equations I know there is a meaning behind, that I just don't know enough to grasp.

 

I think your equations don't qualify as having meaning behind. So I don't think you have any basis for degrading the math of Einstein and Minkowski. I am fairly sure your math falls very short of theirs.

 

Regards, TAR2

Scientists don't disprove my equations.I think because they can't. My equations make predictions(Einstein and Minkowski didn't make the same predictions). Financed experiments can check the predictions.

[tar]

DimaMazin,

 

Could you frame the predictions in English sentences, with object, subject and predicates, so that I as a math handicapped individual, might understand what it is you wish to prove or predict?

 

Regards, TAR2

[DimaMazin]

DimaMazin,

 

Could you frame the predictions in English sentences, with object, subject and predicates, so that I as a math handicapped individual, might understand what it is you wish to prove or predict?

 

Regards, TAR2

For example.Traveler travels (only in our galaxy) at 200,000,000 m/s relative to us(we measure it).Then he measures our speed relative to him as 119,966,779 m/s

[DimaMazin]

When a traveler uses frequency of light for definition of speed of resting object then he(she) should use my equation

 

f_s=f₀ * gamma * (1 + v' * cos theta / [c-v'])

 

v' - speed of resting object in gravitational space relative to traveler in traveler's coordinates

[DimaMazin]

When scientists incorrectly define speed of object they incorrectly define mass of the object.