Below is Randy Poe's attempt to handle a coordinate system
which the imbecile Dirk Van de moortel says I do not understand.

Randy Poe:
I'm going to take another tack, one which may dispense with
all this endless origin silliness. The kind of argument that
could result from trying to introduce and then solve Einstein's
differential equation could keep us here till the heat death
of the universe.

Let's look at the transit time of the light signals.


Now, from the point of view of S, the emitter and mirror
are some distance d apart. The light signal leaves the
emitter at x1, at time t1. It is traveling toward the
mirror at speed c, but at the same time the mirror is
receding at speed v. So from the point of view of the S
observer, the transmit time from emitter to mirror is
d/(c-v). Which means t2 = t1 + d/(c-v).


On the return trip, the light signal is coming back at
c and the apparatus at the back of the truck is rushing
to meet it at speed v. They converge at a rate of c+v,
and the transit time is d/(c+v). Which means t3 =


t1 + d/(c-v) + d/(c+v)
t3 = t1 + d/(c-v) + d/(c+v)= t1 + d*[1/(c-v) + 1/(c+v)]= t1 +
d*[(c+v)/(c^2-v^2) + (c-v)/(c^2-v^2)]= t1 + d*[(c + v + c - v)/(c^2 -
v^2)]= t1 + d*[2c/(c^2 - v^2)]Or


t3-t1 = d*[2c/(c^2-v^2)] - Randy

In Einstein's and Poe's world.
_____________________ _
[Poe's Trucking Inc.] [ \_
[___________________]_[___| t1
| oo oo o
|--------d-------|
|
|
__________________________ _
[ Poe's Trucking Inc. ] [ \_
[________________________]_[___| t2
| oo oo o
|-----------d----------|
| |
| |
| |
________________________________ __
[ Poe's Trucking Inc.] [ \_
[______________________________]_[____| t3
| oo oo o
|-------------d--------------|
| |
| |
|
(x1,t1) (x2,t2)
(x1,t3)

In Einstein's coordinate system:

½[tau(0,0,0,t)+tau(0,0,0,t+x'/(c-v)+x'/(c+v))] = tau(x',0,0,t+x'/(c-v))

In Poe's coordinate system:

½[tau(x1,t+t1)+tau(x1,t+(d-vt)/(c-v)+(d-vt)/(c+v))] =
tau(x2,t+(d-vt)/(c-v))



In the real world:


_____________________ _
[ Androcles' Artic ] [ \
[___________________]_[__| t1
| ooo oo o
|--------d-------|
|
|
| _____________________ _
| [ Androcles' Artic ] [ \
| [___________________]_[__| t2
| ooo oo o
| |--------d--------|
| |
| |
| |
| _____________________ _
| [ Androcles' Artic ] [ \
| [___________________]_[__| t3
| ooo oo o
| |--------d--------|
| | |
|v(t3-t1)| |
| | |
(x1,t1) (x3,t3) (x2,t2)


it so quite obvious, from inspection, that neither Poe not moortel

know what a coodinate system is. I have agree with Poe that his

endless origin silliness is just that: silliness. The only thing

the reader need decide is just who is being silly.

Androcles.