Need to resort to spherical wavefront to derive the LTs?

[Dale]

I never said that I want to minimize the assumptions!!!! I just said that I want to have a clear idea about which are needed and which are not

That is minimizing the assumptions. If an assumption is not needed then you can discard it and use fewer assumptions.

Please stop questioning what the object of the OP is, It is what Ibix said in his post 108 and I confirmed in post 110 … Yet the truth is that the object is clear

If a reader must wade through 110 posts to get a statement of purpose from the OP then the object of the thread is not clear. I am not questioning your good faith, but the outcome of this thread is a mess. The title and your OP are not focused on the interval but also on the Lorentz transform. The derivation you were first focused on was a derivation of the Lorentz transform. So in your mind you may now be certain of what you want, but that doesn’t make it true “that the object is clear” to the rest of us.

deriving the ST interval (full stop, not LT) and, yes, of course, being clear on how (on the basis of which assumption this has been done). Is that so difficult to understand?

You can derive the spacetime interval by first deriving the Lorentz transform and second showing that the form of the interval is invariant under the Lorentz transform. That is a perfectly legitimate derivation. You have rejected this legitimate approach. So, yes, it is difficult for me to understand.

 

[Saw]

You can derive the spacetime interval by first deriving the Lorentz transform and second showing that the form of the interval is invariant under the Lorentz transform. That is a perfectly legitimate derivation. You have rejected this legitimate approach. So, yes, it is difficult for me to understand.

I will in the end agree that this is crazy... Come on, who said that that (first LT, later ST) is not a legitimate approach? Who has rejected that approach? I have just said that the other approach, which is also legitimate (first, ST, then LT), is the one that I am interested in, for whatever reason. This is the last time that I answer a comment about the object of the thread. If you want to discuss how to derive the *ST interval* and on which assumptions, few or many, welcome. Otherwise, I can understand that you prefer to drop out, but don't clutter the thread with more comments about the object of the thread, 'cause this makes it actually unfollowable.

 

[berkeman]

I will in the end agree that this is crazy...

Thread closed for Moderation...

 

[Dale]

Come on, who said that that (first LT, later ST) is not a legitimate approach? Who has rejected that approach?

You did:

I am not interested (in this thread) in deriving the LTs and then noticing that they "preserve a particular quadratic form in spacetime"

Anyway, your question as finally clarified is already answered. So we will leave this thread closed.