What are your best arguments for time dilation, so duration is different ?

[digi99]

There's only one world but different ways of defining how we measure it. Each frame uses its own length standard and time standard to establish a set of coordinates to define locations and times and that is the reason different frames have different sets of coordinates but they are all interconnected through the Lorentz Transform. So once you establish a scenario in one frame, you can't just switch to another and start talking about what's going on there, you have to use the Lorentz Transform to see exactly what the coordinates are in the second frame.

Thanks very much for your answers Ghwellsjr.

1 day later (its like a circle) I understand I understood it well, but my communication must be more matched on physics communication, so I try from now on this doing better and not to quick mixing things by answering to fast. So more carefully in formulating.

I realize too just as you said length contraction and time dilation goes hand in hand.

Thats what I am thinking for a while in my blogs and my own website, its just the ration distance / time = C everywhere in the universe (discovered by light in space, so represented by light in space but not on earth, than it is just that ration). I am thinking in two scenarios all the time, if true and if not true.

So when something B is relative moving in a frame you choose, in relation to something A standing still, both see each other smaller (lets say the same size when both standing still), but I think its only an effect because of the general rule distance / time = C, so it is not necessary to find an explanation physically why its length contracted, its just because of the relation distance / time = C. So length and distance are time depended and vice versa. Thats expressed in Lorentz.

So in my first topic and on my website explaining everything is going smaller, a lightwave too (and its amplitude), is just the effect of distance / time = C and no other physical explanation on atom level. That e.g. mass is depended on a possible Higgs field is different and has nothing to do with relativity.

But there is still no contradiction that there is a centre (an absolute world) were all is standing still and has its origanal size, and for what is moving Einstein is valid.

Ready for the General Relativity (?), no because this all takes time for me to accept but slower and slower I will accept it. The trigger for me is the length contraction, it must be time depended, but first I have to see for myself if there are no other explanations possible and if affects this all duration or not.

Why distance / time = C, is just a law to accept I guess, like someone said in a forum, if you don't like it you just have to go to another universe :).

Agreed ? (read distance / time = C, just as the lightspeed, so no new theory)

To be sure in understanding, would an exact device where width, height and length are important for working very well in a frame when standing still, still working for a higher speed let's say close to the lightspeed ?

 

[ghwellsjr]

I agree that all reference frames are equally valid. I was just confused by your statement that there's no reason to "prefer our own reference frame"

These are all great reasons to prefer our own reference frame:

• "calculations are simpler"
• "it's easier to discuss"
• "it's easier to visualize"

But preference isn't just a matter of logic. It's a matter of artistic, and aesthetic opinions and values.

Imagine trying to describe a football game in the rest frame of a muon traveling 99.99% of the speed of light. It would all be flat, and slow-motion, with things moving from the left-to-right really fast, and moving from right-to-left really slow.

For me, not being particularly fond of football, and quite interested in relativity, I probably prefer to see the game in the reference frame of the muon, just to see what it would look like.

But for someone who likes football, more than relativity, they would probably prefer to see it in the reference frame of the football stadium. Or better yet, from quickly changing, low-velocity reference frames as multiple cameras zoom in and follow the action.

A person in the stadium is not concerned with a reference frame and it doesn't matter what reference frame we use to analyze what he sees. All reference frames will agree on what he sees, even the muon's frame. If you pick the muon's frame, you will just see a bunch of weird coordinates that you will then have to reinterpret to determine what someone in the stadium actually sees.

Now if you meant watching a football game from the rest frame of a muon, then you will have to start eons ago and far away and continue to eons in the future and all you will see is a pinpoint of blue-shifted light that then eventually gets large and then you have to look backwards and watch the rest of the game as a pinpoint of red-shifted light. A frame doesn't let observers see things that "we" can see as a result of assigning coordinates to distant events from an observer in the frame.

But if you meant watching the game as a muon would see it, then there won't be much to see since the muon doesn't last very long.

 

[JDoolin]

Thanks JDoolin, I understand exactly now what you said ... our live is the matrix :) ..

Length contraction is my best argument now for relativity, not yet for duration ..

No. That sounds like it may be a reference to the movie "The Matrix." It doesn't sound like you understand what I said at all.

What I'm saying is that Everything that you see is real. Everything I see is real. If we both look at the same object at the same time, we see different things. But my perspective is just as real as your perspective.

All perspectives/frames are equally valid, and just as real as any other.

 

[JDoolin]

A person in the stadium is not concerned with a reference frame and it doesn't matter what reference frame we use to analyze what he sees. All reference frames will agree on what he sees, even the muon's frame. If you pick the muon's frame, you will just see a bunch of weird coordinates that you will then have to reinterpret to determine what someone in the stadium actually sees.

Now if you meant watching a football game from the rest frame of a muon, then you will have to start eons ago and far away and continue to eons in the future and all you will see is a pinpoint of blue-shifted light that then eventually gets large and then you have to look backwards and watch the rest of the game as a pinpoint of red-shifted light. A frame doesn't let observers see things that "we" can see as a result of assigning coordinates to distant events from an observer in the frame.

But if you meant watching the game as a muon would see it, then there won't be much to see since the muon doesn't last very long.

I realize now, there are a couple different definitions to the word "preferred."

(1) to put before something or someone else in one's liking, opinion, etc.; like better
(2) to give preference or priority to

You are absolutely right by definition 2, there is no reason to prioritize one reference frame over another. Namely because all reference frames are equally valid.

However, I was thinking of the more "opinion" version of preferred (definition 2). As in, most people would prefer to watch a football game in the rest-frame of the football stadium, as opposed to the rest frame of some muon traveling past the stadium at near the speed of light.

Your statement above: " If you pick the muon's frame, you will just see a bunch of weird coordinates that you will then have to reinterpret to determine what someone in the stadium actually sees." is confusing, though. That actually does sound like something out of "The Matrix." ;)

I don't know if you've seen this movie, but there are scenes in the movie, where mathematical symbols are more-or-less falling from the sky like rain, and there were parts of the movie where they really did "just see a bunch of weird coordinates."

I'm sure that's not what you meant, though.

 

[digi99]

No. That sounds like it may be a reference to the movie "The Matrix." It doesn't sound like you understand what I said at all.

What I'm saying is that Everything that you see is real. Everything I see is real. If we both look at the same object at the same time, we see different things. But my perspective is just as real as your perspective.

All perspectives/frames are equally valid, and just as real as any other.

Thanks for your answer (I am happy to hear this, because it became more and more misty for me, I have to learn this all from remarks in this forum), you gave me in fact an answer on a problem I had, read next:

"I still find 1 thing difficult to see. The much known triangle how Lorentz can be derived in a more simple way (see wiki). If a light source is moving horizontally which let bounce 1 vibrating photon (pulse, direction vibration is horizontally) vertically between 2 mirrors (with speed of light C), we as standing still see that passing photon as two legs of a triangle (compare with a passing translucent train where somebody let's bounce a ball and we look to it from a station). Ok the direction of the photon is to understand for me (like the ball), but the vibration direction of the photon changes too (perpendicular to the legs of the triangle) for which the vibrated photon again may be seen as a beam (pulse) by us (and so again the speed of light is C)."

So both observers looks to the same pulse at the same moment from different frames, both see the same "photon" (pulse) but another vibration direction.

Is there an explanation (theory) we see different things (e.g. like many dimensions), or just to accept because this is nature (probably all must fit at any moment in physics laws in all frames for all observers, could be a logic reason) ?

 

[ghwellsjr]

A person in the stadium is not concerned with a reference frame and it doesn't matter what reference frame we use to analyze what he sees. All reference frames will agree on what he sees, even the muon's frame. If you pick the muon's frame, you will just see a bunch of weird coordinates that you will then have to reinterpret to determine what someone in the stadium actually sees.

Your statement above: " If you pick the muon's frame, you will just see a bunch of weird coordinates that you will then have to reinterpret to determine what someone in the stadium actually sees." is confusing, though.

Sorry, I didn't mean to be confusing. Let me see if I can explain it better:

My first point was that a person who watches a football game is not cognizant of any reference frame. The purpose of a reference frame is to give coordinates to events that are distant from the origin or from any observers that we are considering. When an observer in the stands sees the football hitting the ground somewhere, he doesn't think, "Well, since the distance to that event is defined in my rest frame to be 200 feet, it must have occurred 200 microseconds before I saw it happen". And when he sees a player jump the line of scrimmage and the ref calls a penalty, he doesn't analyze it to see if in his frame of reference the penalty was really deserved.

My second point is if you want to use a frame of reference to analyze what a person in the stadium actually sees, you will have to describe the action on the playing field in terms of events and then calculate how long the image of those events takes to reach the person's eyes at the speed of light and at what angle they enter his eyes so that you can then determine what he actually sees. Now if you use the stadium's rest frame to describe the action and you want to use a muon's rest frame to analyze what the person in the stadium will see, you will have to transform all the events into the rest frame of the muon and do the calculations of how the events appear to the person in the stadium, so both the action on the field and the person watching the game will be traveling at a very high speed making the calculations very difficult. And for all that work, you will conclude that he sees exactly the same thing as when you analyze everything using the stadium's rest frame.

Does that clarify what I meant?

 

[JDoolin]

Thanks for your answer (I am happy to hear this, because it became more and more misty for me, I have to learn this all from remarks in this forum), you gave me in fact an answer on a problem I had, read next:

"I still find 1 thing difficult to see. The much known triangle how Lorentz can be derived in a more simple way (see wiki). If a light source is moving horizontally which let bounce 1 vibrating photon (pulse, direction vibration is horizontally) vertically between 2 mirrors (with speed of light C), we as standing still see that passing photon as two legs of a triangle (compare with a passing translucent train where somebody let's bounce a ball and we look to it from a station). Ok the direction of the photon is to understand for me (like the ball), but the vibration direction of the photon changes too (perpendicular to the legs of the triangle) for which the vibrated photon again may be seen as a beam (pulse) by us (and so again the speed of light is C)."

So both observers looks to the same pulse at the same moment from different frames, both see the same "photon" (pulse) but another vibration direction.

Time dilation is derived in a simple way, yes. However, once you make that derivation, you have to account for the symmetry of the situation. If I see YOUR clock going slower than mine, and you see MY clock going slower than yours, we cannot have a shared simultaneity.

Much like forward, backward, left, right, up, and down, which are observer-dependent directions, future, past, and simultaneity are observer dependent. Now when I say "observer dependent" I DO NOT mean ambiguous, unclear, inexact, open to interpretation.

The observer dependency of future, past, and simultaneity are explicit, fully defined, leaving no room for confusion or doubt.

When you look at a coin from an oblique angle, you see what you see. If you didn't see what you see, then you wouldn't know where the coin was. You wouldn't have any idea where to reach to pick it up. You can decide to "interpret" what you see, saying that coin is "round" and there's no reason to "prefer" describing the coin as an oval, over describing it as "round" but in order to literally see the round shape, you have to line the coin up in a certain way with your eye.

Is there an explanation (theory) we see different things (e.g. like many dimensions), or just to accept because this is nature (probably all must fit at any moment in physics laws in all frames for all observers, could be a logic reason) ?

Is there a theory that explains why I see the back of the coin, while you see the front of the coin, but we both agree that it is the same coin? I would recommend a reading of Bertrand Russell's "The Problems of Philosophy" You might benefit from a comparison of Empiricism, Idealism, and Rationalism. (I don't know if any of this develops a "theory" but it certainly does emphasize the question.)

 

[JDoolin]

Sorry, I didn't mean to be confusing. Let me see if I can explain it better:

My first point was that a person who watches a football game is not cognizant of any reference frame. The purpose of a reference frame is to give coordinates to events that are distant from the origin or from any observers that we are considering. When an observer in the stands sees the football hitting the ground somewhere, he doesn't think, "Well, since the distance to that event is defined in my rest frame to be 200 feet, it must have occurred 200 microseconds before I saw it happen". And when he sees a player jump the line of scrimmage and the ref calls a penalty, he doesn't analyze it to see if in his frame of reference the penalty was really deserved.

My second point is if you want to use a frame of reference to analyze what a person in the stadium actually sees, you will have to describe the action on the playing field in terms of events and then calculate how long the image of those events takes to reach the person's eyes at the speed of light and at what angle they enter his eyes so that you can then determine what he actually sees. Now if you use the stadium's rest frame to describe the action and you want to use a muon's rest frame to analyze what the person in the stadium will see, you will have to transform all the events into the rest frame of the muon and do the calculations of how the events appear to the person in the stadium, so both the action on the field and the person watching the game will be traveling at a very high speed making the calculations very difficult. And for all that work, you will conclude that he sees exactly the same thing as when you analyze everything using the stadium's rest frame.

Does that clarify what I meant?

I think you're answering a different question than what I was expecting.

My question is "what does the hypothetical observer in the rest frame of the muon see?"

It seems like you are answering "What does the hypothetical observer in the rest frame of the muon calculate that the football player sees?"

The football player does not have to do any calculations to figure out what he sees. And the observer in the rest frame of the muon shouldn't have to do any calculations to figure out what it sees, either.

 

[ghwellsjr]

In post #30 you asked about what an observer in different reference frames would see when watching a football game. Since I wasn't sure what exactly you were asking, I gave three different answers in post #32. Then in post #34 you quoted from the first of those three answers and asked for clarification which I gave in post #36. Now you're asking about the other two of those answers and again, I don't know which one you mean.

But all along I'm trying to get you to quit thinking in terms of a frame of reference when asking what an observer sees because it has nothing to do with what a frame of reference is for. Here's how you should ask the question: "what does the hypothetical observer traveling for a long time at the speed of a muon see?" (my second answer) or "what does the hypothetical observer traveling with a muon see?" (my third answer). You then can use any frame of reference to analyze those situations, even the rest frame of the stadium, in fact, that is the one I prefer (your alternate definition of prefer).

 

[JDoolin]

In post #30 you asked about what an observer in different reference frames would see when watching a football game. Since I wasn't sure what exactly you were asking, I gave three different answers in post #32. Then in post #34 you quoted from the first of those three answers and asked for clarification which I gave in post #36. Now you're asking about the other two of those answers and again, I don't know which one you mean.

Okay, I'm sorry about that. I didn't realize you were answering three different questions. I was also not thinking about the fact that muons are actually only created in the upper atmosphere, and only last for a very short time.

Now if you meant watching a football game from the rest frame of a muon, then you will have to start eons ago and far away and continue to eons in the future and all you will see is a pinpoint of blue-shifted light that then eventually gets large and then you have to look backwards and watch the rest of the game as a pinpoint of red-shifted light.

This is a pretty good answer to the question I meant to ask. Although technically if you watch the football game from that frame you won't start eons ago. If you went past the game at half-time, you'd watch the first half of the game in fast-forward, (blue-shifted), and the last half the game in slow-motion for eons.

 

[ghwellsjr]

This is a pretty good answer to the question I meant to ask. Although technically if you watch the football game from that frame you won't start eons ago. If you went past the game at half-time, you'd watch the first half of the game in fast-forward, (blue-shifted), and the last half the game in slow-motion for eons.

I like that, except I kind of overstated the time factor. Muons travel at about 0.98c with a gamma of 5 so if we considered a two-hour football game (no commercials), the first half would start for the muon-observer about one-half hour after the beginning of the game at about a distance of one-half light-hour away. The muon-observer would then see the first half at ten-times fast motion for him and blue-shifted. This would take about six minutes for him (one-fifth of a half hour). Then he would face the other way as he whizzed past the stadium and watch the second half at one-tenth slow motion for him and red-shifted. This would take about ten hours for him and would last until about fifty hours after the end of the game at which point he would be located about fifty-one light-hours away.

Thanks for the added insight into this situation.