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

Bill Janssen billj at ieee.org
Wed Mar 29 19:13:07 EST 2006

```Don Moss wrote:

>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
>
>
The way I understood the explanation is that the "instruments" used to
measure length or time
were unusable at the Planck time etc.

Bill K7NOM

```