Gumby The Green said:
What is that based on though?
The fact that what each observer sees in the Doppler shifted light signals they receive is a direct observable and is invariant. There's no calculation involved; there's no "correction" because of some choice of coordinates. There's just what each observer directly sees, and they directly see all other observers' clocks running forward.
Gumby The Green said:
If the signals don't accurately depict the exact speed of the distant clock's "flow"
No signal can possibly "accurately depict the exact speed of the distant clock's flow" if the distant clock is in motion relative to the observer.
Gumby The Green said:
how are you sure that they accurately depict its direction in the traveler's frame at all times
Because the
ordering of the light signals between emitter and detector is invariant. That is a simple physical fact about how light propagates. All of the light signals are moving in the same direction and at the same speed.
Gumby The Green said:
(even while its behind the traveler's Rindler horizon)?
If the distant object is behind the traveler's Rindler horizon, the traveler can't see it at all;
no light signals are received. And the "accelerating frame" you are implicitly using for the traveler won't even cover the region of spacetime behind the Rindler horizon; it only covers the portion of spacetime that the traveler can actually see, i.e., receive light signals from. So objects behind the traveler's Rindler horizon are simply not included at all in the entire scenario you are talking about.
Gumby The Green said:
I'm not making any claims about what's actually happening to the distant observer in their own frame. All I care about is what's true in the Traveler's frame.
There is no such thing as "what's actually happening to the distant observer in their own frame" as contrasted with "what's true in the Traveler's frame". Coordinates and frames don't tell you what's "true". They are conveniences for calculation. They are not physical things and they do not tel you physical things.
"What's true" is contained in
invariants: things that are independent of any choice of coordinates. In other words, "what is true" must be
the same in
all frames. The time an observer reads on their own clock at a particular event, such as emitting a particular light signal, is an invariant. What an observer actually sees in a Doppler shifted light signal arriving from a distant object is an invariant. But "what time is it for a distant object at a given event for the traveler" is
not an invariant. It depends on your choice of coordinates and is a convenience for calculation; it doesn't tell you anything about "what is true".
Unless and until you are able to properly grasp the above, you will continue to make mistakes and you will continue to say wrong things that we have to correct.
Gumby The Green said:
I'm not applying any correction to the Doppler shift.
Yes, you are: in order to calculate what you are calling "what's true in the traveler's frame", you
have to apply corrections to the Doppler shifted information in the light signals the traveler receives. If you just take the Doppler shifted information as it is, you are working with invariants that aren't "in" any frame, they are just invariants. But you refuse to do that; you insist on talking about "what is true in the traveler's frame" as thought it had physical meaning. It doesn't.
Gumby The Green said:
I don't care about the Doppler shift or about anything the traveler sees.
And you
should. That's the point. What the traveler actually sees is invariant. What you are calling "what's true in the traveler's frame" is not, and has no physical meaning. So you're focusing on the wrong thing.
Gumby The Green said:
My argument is all about what can be logically deduced at the end of the journey from the most basic principles.
You might think it is, but you are wrong. What you are doing is not based on any physical principles. It is based on incorrectly treating coordinate-dependent quantities as though they had physical meaning. They don't.