One-way tests of special relativity

[grav-universe]

If you're sure you can provide an on-line reference to this idea that frames can contain only things at rest, then please do.

This is the standard definition of a frame of reference. See Wiki for example.

Let me emphasize once more: all clocks, all objects, all observers, all ships, all buoys, all planets, all everything that you want to consider in a scenario is in every frame that you want to consider.

So you are saying that a frame of reference includes all clocks and rulers? Then what would be the purpose of referring to "clocks within a frame" rather than just "all clocks"? Why refer to a frame at all in that case, rather than just "the universe"? If all frames include everything, then what is the difference between them?

I am considering a stationary frame, one in which all observers and measuring devices are stationary, while you seem to be considering some type of universal frame, with no emphasis upon what is stationary and what is moving. That would become confusing very quickly in discussions, this one for example.

We have a frame A. Do observers in frame A use stationary rulers and clocks to measure from their own frame of reference or do they use moving rulers and clocks. Does frame A include all stationary and moving observers? What is your definition of a frame of reference? We have a frame B. Does frame B include the observers from frame A? What is the difference between the two frames? What would it mean to say that frame B is moving at .6 c with respect to frame A?

This explains why you don't understand time dilation--if no clock can move in a frame then no clock can be time dilated. Same with observers. No one ever said that an observer has to be stationary in a frame or remain stationary in a frame.

The clocks that are used to measure time dilation within the frame are stationary. It is a stationary frame, the frame of observation and measurement, using only stationary rulers and clocks. The moving clock is moving relative to that frame. It is not in the same frame from which we measure.

There is nothing special about any frame and you never, ever, need more than one frame to describe, analyze, and calculate what is going on in any given scenario. But once you have chosen a particular frame to do that, you can transform all the significant events into any other frame and it will be just as valid, and no more special, than the first frame.

Right.

We don't need any observers in any frame. Note in my previous post, I didn't have any observers, just three clocks and I described how they were time dilated differently in the two different frames and yet produced the same time on them when they arrived at their destination points. If you want to add any more additional clocks, that's alright, but they are no more significant that any other clocks. Just because some clocks are stationary in one frame doesn't provide the explanation of what time dilation is all about. They are subject to the same rules of time dilation as moving clocks. And, as I said before, you only need one clock to talk about and demonstrate what time dilation is all about and how it is different in different frames.

Right, you mentioned that observers measure, but all we really need to consider is the clocks themselves. We would need two clocks to measure one way time dilation, but only one clock would be necessary if you are considering that we could have the clock return without regarding what the time dilation would be each way, only the end result.

 

[ghwellsjr]

This is the standard definition of a frame of reference. See Wiki for example.

OK, I looked up the wikipedia article on "Frame of Reference". I look down to the section on "Simple example". First they describe a frame in which the road is stationary and two cars are moving at different speeds. Then they look at the same scenario from a frame in which the first car is stationary and finally one in which the second car is stationary. They point out how much easier the problem is by choosing a suitable frame of reference.

So you are saying that a frame of reference includes all clocks and rulers? Then what would be the purpose of referring to "clocks within a frame" rather than just "all clocks"? Why refer to a frame at all in that case, rather than just "the universe"? If all frames include everything, then what is the difference between them?

As the wiki example pointed out, you only have to consider certain items in your frame, not the whole universe. They considered the road and two cars. You consider whatever you want to. But when you look at the scenario from different frames, you don't exclude some of the items. In the first frame where the road was stationary, they included the two moving cars. In the other two frames, they included both cars, even though only one of them was stationary.

I am considering a stationary frame, one in which all observers and measuring devices are stationary, while you seem to be considering some type of universal frame, with no emphasis upon what is stationary and what is moving. That would become confusing very quickly in discussions, this one for example.

Just as in the wiki example--you say what is stationary and what is moving. That's not confusing.

We have a frame A. Do observers in frame A use stationary rulers and clocks to measure from their own frame of reference or do they use moving rulers and clocks. Does frame A include all stationary and moving observers? What is your definition of a frame of reference? We have a frame B. Does frame B include the observers from frame A? What is the difference between the two frames? What would it mean to say that frame B is moving at .6 c with respect to frame A?

You have an adequate understanding of how to define or construct a frame of reference using rigid rulers and synchronized clocks spread out through the frame. Your problem is that you haven't grasped the notion that these rulers and clocks are imaginary. Once you understand the process for building a reference frame, you don't actually use real rulers and clocks, otherwise, how could anything move through them? It's a coordinate system like the latitude, longitude and altitude we have on the earth. There are not a bunch of rulers or markings across the land and seas pointing out the coordinates, we just imagine them to be there.

The clocks that are used to measure time dilation within the frame are stationary. It is a stationary frame, the frame of observation and measurement, using only stationary rulers and clocks. The moving clock is moving relative to that frame. It is not in the same frame from which we measure.

Right.

Right, you mentioned that observers measure, but all we really need to consider is the clocks themselves. We would need two clocks to measure one way time dilation, but only one clock would be necessary if you are considering that we could have the clock return without regarding what the time dilation would be each way, only the end result.

Once you realize that the rulers and clocks that you use to build the reference frame are imaginary, then you can populate the frame with whatever you want. I want there to be just one clock moving at some speed. Now I use the formulas to calculate its time dilation. No measurement is required.

Now I can if I want include other clocks and synchronize them as you have described and show how in a frame in which they are at rest, they are not time dilated and a moving clock is and I can show how the measurements match the calculation of SR but I can also show how in another frame the time dilations are all different.

 

[grav-universe]

Okay, fair enough. Stated that way, looks like we can generally agree. :)