[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: where does time go



On Fri, Oct 31, 2025 at 04:23:46PM +0000, fxkl47BF@protonmail.com wrote:
> On Fri, 31 Oct 2025, Nicolas George wrote:
> 
> > fxkl47BF@protonmail.com (HE12025-10-31):
> >> i run a command preceded by time and pipe it to mail
> >> the results of time is not included in the mail
> >>
> >> time sleep 2 2>&1 | mail -s foo bar@localhost
> >
> > Try this:
> >
> > time sleep 3 | sleep 10
> >
> > … observe carefully the output and deduce something important about
> > time.
> >
> 
> that's easy
> the electrons are moving near the speed of light
> so time slows down :)

The electrons move actually pretty slowly. It's the electrical field
what moves quickly.

Let's assume copper, at a density of 8.9 g/cm^3, and an atomic weight
of 63.5: 1mm^3 of copper has 6.02*10^23 * 8.9 * 10^-3 * (1/63.5) atoms,
i.e. 8.44 * 10^19 atoms, each contributing one electron to the conduction
band (the last lone S1). At 1.6 * 10^-19 C, that makes 13.5C of charge
available for conduction in each mm^3, which is a friggin' lot.

If you push 1A across a wire with a cross section of 1mm^2, your
electrons would be moving at 1/13.5 mm/s, i.e. 0.074 mm/s: I can
hear the snails in my garden yawning :)

I might have lost an order of magnitude here or there, but the kind
of result is somewhat consistent with the dim memories I have from a
former life...

Cheers
-- 
t

Attachment: signature.asc
Description: PGP signature


Reply to: