[time-nuts] Are there limits to the accuracy of clocks?

Don Moss moss at microwave.nsstc.nasa.gov
Wed Mar 29 18:45:25 EST 2006

```On Wed, 29 Mar 2006 Ulrich Bangert wrote:

> Hal,
>
> i guess a physicist's answer to your question would be something like
> that:
>
> Question:
> What is Planck length? What is Planck time?
>
> The Planck length is the scale at which classical ideas about gravity
> and space-time cease to be valid, and quantum effects dominate. This is
> the ?quantum of length?, the smallest measurement of length with any
> meaning.
>
> And roughly equal to 1.6 x 10-35 m or about 10-20 times the size of a
> proton.
>
> The Planck time is the time it would take a photon travelling at the
> speed of light to across a distance equal to the Planck length. This is
> the ?quantum of time?, the smallest measurement of time that has any
> meaning, and is equal to 10-43 seconds. No smaller division of time has
> any meaning. With in the framework of the laws of physics as we
> understand them today, we can say only that the universe came into
>
> Regards
> Ulrich

Ulrich,

I'm a little "uncertain" how to interpret this.  Does that mean that time
and distance (length) are granular rather than continuous?  So there are
only discrete moments, and time doesn't flow smoothly; it jumps from one
instant to the next, and the instants are separated by the Planck time?
Put another way, if the instants of time were represented on a number
line, the points would not cover the line, but would be separated by the
Planck time.  And all meaningful time intervals are integral multiples of
the Planck time.  And the universe could be said to jump from one state
to the next, much as it would in a computer simulation with an ultrafine
granularity.  And analgous statements could be made for length.

Is this the right idea, or is that not the way to look at it?

- Don

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