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

Mike S mikes at flatsurface.com
Wed Mar 29 19:40:28 EST 2006


At 06:45 PM 3/29/2006, Don Moss wrote...
>> 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.
>>
>> 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. 
>
>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?

If time and distance were constrained to integral Planck units, how could there be any speed other than light speed or integral divisors thereof? It would require velocity to be discontiguous - going at light speed while moving one Planck distance in one Planck time, then pausing (for an integral number of Planck times - so the next slowest speed would be 1/2 c), then moving one Planck distance in one Planck time. How would an electron travelling at 70% c "know" to pause 1 here, 0 there, whatever it takes to satisfy the measurement? The physicist would likely answer that quantum uncertainty fills the gaps and that it cannot be understood in human terms, only mathematical - but that's simply petitio principii. 

I think the key is that physics at that level _is_ just math, not reality. That experimental results work only reflects that we've created a fairly self-consistent model, not discovered true nature. Newtonian physics works in most real-world cases. Relativistic physics covers almost everything else. Quantum theory (or QED, or string theory or the Higgs boson, or whatever else) are simply closer approximations of full self-consistency (which shouldn't be confused with reality). 

At some point, I think we run into Godel - we can't self-refer and be complete in our understanding, so if what we're trying to figure out is the physics of our own nature, it simply can't be done. 

I know it doesn't satisfy human nature to say "we don't and can't know what time _really_ is" but I think that is the case. 



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