Re: Scaled or Granular Dates

From: Jonathan Leffler <jleffler_at_earthlink.net>
Date: Thu, 08 Jan 2004 18:16:52 GMT
Message-ID: <o8hLb.544$Pg.287@newsread1.news.pas.earthlink.net>

--CELKO-- wrote:

>>>All Dates in Java, and I believe in most all areas of computing are

> measured as distinct points in time to some predefined granularity.
> <<
>
> Which is clearly wrong. Einstein told us that to exist exist an
> entity must have a duration. Heck, as far back as Zeno, we know that
> a continuum like time is defined by the property of always being
> divisible (i.e. no discrete points).

So, have you read the article on Loop Quantum Gravity in the January 2004 Scientific American? It is mind blowing. It might also be wrong. The preamble reads 'We perceive space and time to be continuous, but if the amazing theory of loop quantum gravity is correct, they actually come in discrete pieces'. The quantum of distance is a Planck length of 1E-33 cm (which is, I think, 1E-35 m), and the quantum of time is a Planck time of 1E-43 seconds. Granted, those quanta are many orders of magnitude more tiny than anything we currently measure - in databases, anyway - but maybe the sweeping statement about continuity of time is overstated.

There's also a book "Time Granularities in Databases, Data Mining, and Temporal Reasoning" by C Bettini, S Jajodia, S X Wang, published by Springer, 2000, ISBN 3-540-66997-3 (in Engish, despite the ISBN prefix suggesting German). I've not read it all yet - on the to do list - but it might be of some relevance, too.

-- 
Jonathan Leffler                   #include <disclaimer.h>
Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com
Guardian of DBD::Informix v2003.04 -- http://dbi.perl.org/

Received on Thu Jan 08 2004 - 12:16:52 CST