[ExI] QT and SR

[Lee Corbin]

Mike writes

> Lee wrote:
> 
> > Suppose that 20 mighty spaceships with extremely
> > powerful nuclear engines are all lined up nose to stern
> > on a very long runway at the spaceport, except for 
> > a 10 meter stretch between each pair. All their clocks 
> > are synchronized, and their orders are as follows: 
> > "At exactly 12 noon in our local time zone, you are
> > to all take off, accelerating at one gee until you
> > reach velocity c/2, at which point you will continue
> > at velocity c/2 relative to our solar system."
> 
> is this magic string that doesn't break or melt from the
> mighty spaceship exhaust?

I hadn't thought of that. I wonder if John Bell did. Anyway,
Damien has just provided an engineering solution:

      As any fule kno, each vessel is propelled by a pair
      of mighty engines mounted on struts, and these are
      rotated by 18 degrees in each consecutive craft,
      so their exhaust flumes pass safely.

Bravo!  A theoretical solution to the String problem.

> You are going to post your explanation now that everyone
> has had a day or so to think about, right?

Well, the solution is what has been pointed to in a 
number of web links. Namely, to wit, viz., the 
strings do break. The trap is to fall into thinking
that the effects of Special Relativity are not real
effects, but only depend on the viewpoint of the
observer. This last sentence is characteristically
and fatally ambiguous. There is no dependence
on viewpoint; rather there simply are "frames
of reference", which is not quite the same thing.

I fell into the trap myself when I first heard Bell's
puzzle even though I knew that relativistic effects
are real. It's just that the "viewpoint" logic often
gives the right answer, but not here. Here, in the
sole frame of reference in which the question is
asked, finding out the real answer to the real
behavior of those space ships isn't easy.

I tried my best in a previous post, however, to
describe the best way I know how to get an
answer, and also what's the best way I know
for it to also appeal to the intuition. It was in
the thread "spaceship string theory" posted today.

Lee