OK, thanks for everyone's responses. I believe I have corrected my misunderstandings.
So, as I understand it, as long as B is at rest with respect to A, and they are both at the same time coordinate, then SR does not prohibit instantaneous communications between the two.
Alternatively...
I will proofread my messages better.
Bob and Alice are at (0,-10). How can Bob get to (1,10) in Alice's frame when Alice is at (0,0)? (correcting my original question.)
Ok, Fredrik's setup appears to be incorrect. The event at (1,10) has the same time (in Bob's frame) as the event at...
Ugh. I mixed up the labels in my diagram. Here's the corrected one that is intended to be in the "past" of the F5 diagram. The question is, how does my diagram end up as in F5?Yes, I intended for C and D to be moving in A and B's frame.
In response to Fredrik, how does Bob get to (1,10) in...
OK, in the diagram at the bottom of http://www.theculture.org/rich/sharpblue/archives/000089.html, I see how causality is violated. It's very clear. (Thanks for the reference.) Let's call this F5.
My question is as follows. In order to set up the configuration in F5, Alice, Bob, Carol, and...
OK, there's the math and there's the analogies. I don't know how to apply the frame transformations to answer my question. So I was hoping to come up with an analogy that I can use to understand why the transforms work the way they do. (Or even a space-time diagram.)
My motivation is to...
From my amateur readings in relativity, one of the arguments against tachyons is that causality would be violated locally.
But how?
Let's say we have observer A and B with synchronized clocks that are separated by a reasonable distance d known to them. A sends B a photon at A's clock t0...
Yes, I should have said "related states" rather than "identical states."
Claude Bile, I assume the other photon did not actually change state, but that its superposition of states was collapsed to a single state. So the "spookiness" is actually that somehow the particle switches from a...
Is it even possible to describe entanglement in terms of bags and marbles then? (Yes, I did not understand your explanation at all. Sigh.)
I'll look up nonlocality and see if I can learn something.
Thanks for answering. Still looking for a description...
Aha. OK, it looks like I was...
I'm trying to understand why entanglement is said to be "spooky."
The model I have is that 2 entangled particles are related, such that they have identical states when measured. The entanglement process is what ensures they have identical states. So it's no surprise they measure out the same...