[Physltest] [Phys-L] Re: Twins on cell phones

[David Bowman <David_Bowman@GEORGETOWNCOLLEGE.EDU>]

Regarding Rick's question:

> During our discussion of the Twins Paradox--my version has one twin
> rush off to Alpha Seti 6  (30 ly) to pick up a pizza and returns an
> hour later on his clock--a student asked, what if they were talking
> to each other on cell phones (intergalactic versions) throughout the
> trip.  What does each twin experience.  I think I can figure out
> what the earth twin hears, but am unsure what is going on with the
> travelling twin since in his round-trip he would receive all 60
> years of transmissions from his brother.  Anyone want to tackle
> this?
>
> Rick

I think the analysis may be conceptually a bit simpler if instead of
having cell phone conversations the twins just look back at each
others' self-luminous clocks through their telescopes and
continuously compare the reading observed through their telescope
with their own clock's reading throughout the duration of the trip.

The Doppler shifts in the observed transmissions will be quite
extreme if you use the parameters described above.  I know that cell
phones use spread-spectrum technology, but a 6 order of magnitude
Doppler shift factor is a pretty ridiculous amount of spectrum
shifting.  Of course if the self-illuminated clock method version is
used and the clocks are broadcasting on visible wavelengths the
received blue-shifted transmissions will be gamma rays and the red-
shifted ones will be UHF.  I'd hate to think of the inertial force
jerk exerted on the traveling twin at each end of the one-way path.

David Bowman
_______________________________________________
Phys-L mailing list
Phys-L@electron.physics.buffalo.edu
https://www.physics.buffalo.edu/mailman/listinfo/phys-l