sci.physics.relativity

On Aug 3, 8:43 pm, Ben Rudiak-Gould wrote:
> I haven't reread the text, but based on your comments I don't think there's
> a mistake. It's important that the two worldlines start with the given
> separation so that they have the same asymptotes (namely x = |t|). That way
> the whole setup is Lorentz invariant and hence static in a certain sense --
> every moment is like every other. If you shift them around then it doesn't
> work any more, even if they still don't overlap. The pursuer does have a
> higher acceleration than the pursued -- that worldline (the left one) is
> more tightly curved. The acceleration is the same at every point of each
> worldline, though that's hard to see in the diagram (it looks like it
> decreases as the speed increases, but it doesn't).

Thanks.
So more tightly curled is higher acceleration -- I had it backwards.
I keep confusing myself as to which way the graph is drawn. When
finding the second derivative, I thought I must have made a mistake
until it dawned on me that x is the dependent variable. The function
is sideways on the graph, as expressed as a function of t.

Based on a reply in a different newsgroup, I'm understanding that
initial separation is important. In this case, it must be (K-1).
But, as I said in the original posting, that bothers me. There are no
physical units here. So what does one unit in the x direction mean?