Re: Causation in Physics: F=ma

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

At 02:34 AM 11/15/2003, Stephen Speicher, you wrote:
> [ Brian Whatcott]
> >
> > Supposing I can point to a causal event that is simultaneous
> > with a resulting event in some frame,
>
> "Supposing" such is a contradiction of special relativity --
> there cannot be a causal connection between space-like events.

Supposing that the word "causal" is problematic to Relativists,
let me put this proposition:
"Supposing I can point to an event that is simultaneous
 with a resulting event in some frame"

...does it follow that I can find some frame where either
event precedes the other?

I imagine the answer is
 "yes".


> For two events to be causally related a signal must be sent from
> one event to the other, and special relativity places a finite
> limit on the speed of the signal. All observers will agree on the
> temporal ordering of two causally related events.

Thank you. That was helpful.

> > it looks as though ///  Stephen
> >   is the person to explain why
> > "The relativity of simultaneity"  just ain't so?
> >
>
> The fact that in special relativity the speed of physical signals
> are limited by c, implies the invariance of causality.  This fact
> does not contradict the relativity of simultaneity. Please see
> any decent introductory text on special relativity for a detailed
> discussion of this.
>
> --
> Stephen


I am glad to be reassured that simultaneous events are not
 simultaneous in all frames, but rather, there is a class of
 events called "cause" and "effect" events which need more
careful discussion in order to avoid paradoxes.


Brian Whatcott    Altus OK    Eureka!