[time-nuts] NPR Story I heard this morning
bownes at gmail.com
Tue Nov 4 15:44:12 EST 2014
But won't the doppler effect change as the Cs atoms fall down the gravity
On Tue, Nov 4, 2014 at 3:14 PM, Attila Kinali <attila at kinali.ch> wrote:
> On Mon, 3 Nov 2014 11:54:41 -0800
> Peter Monta <pmonta at gmail.com> wrote:
> > Sorry if this is a bit off-topic. I'd like a simple, clear explanation
> > the layman that drills down on exactly how the current definitional
> > can be realized to arbitrary precision. For example, assume that we must
> > go off-earth at some point to get a better timescale. How fuzzy is the
> > solar potential ("soloid")?
> It will be done as usual: As soon as they can reliably measure an
> effect that is impossible to cancel out, they will redefine or ammend the
> definition of the second to account for this issue.
> And going by the presentations given at EFTF this year, there is quite
> some interest in precision gravity measurements in the time/frequency
> community. And yes, they use the same basic phyiscs as their atomic clocks
> (one apporach is to let Cs atoms fall down a tube and measure their
> acceleration using doppler shift of the hyperfine transitions line)
> Attila Kinali
> I pity people who can't find laughter or at least some bit of amusement in
> the little doings of the day. I believe I could find something ridiculous
> even in the saddest moment, if necessary. It has nothing to do with being
> superficial. It's a matter of joy in life.
> -- Sophie Scholl
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