On Tue, 09 Apr 2002 22:42:28 Barbara and/or Bill Hooper wrote: ... >Nothing questionable about the advantage of greater precision to those who >need such higher precision in their work. Everone else may ignore the >change since CGPM has had the wisdom to always change the definition so that >the new metre is the same length as the old metre. > I wasn't discussing the merit that it DID provide an improvement in accuracy, no question about that. My question was whether such small gain should warrant a change in the official current definition of the meter.
Perhaps one should refrain from "rocking the boat" unless/until an improvement of one full decimal place is achieved. Why? Imagine if for every meager gain in accuracy one would have to change the definition of the meter. Where would we end up? Only confusing standards authorities and rendering effective teaching of metrology too dynamic. One must also realize that changes of this nature do take a significant amount of time until the larger population finally "gets the news". See for instance the case of the degrees centigrades, which still good many people continue to use despite Celsius having replaced it for decades now! ... >No change in philosophy. Oh, yes, it most certainly WAS a change, my friend. We moved from using wavelengths to measure distance to the distance a light *traveled* some fraction of the second! There IS a fundamental difference here, I'm sorry. > One of the values and beauties of SI is the fact >that it has official agencies empowered to make such changes to improve the >system when the need arises. The need to regularly update the system in ways >that have benefits without making previous data unusable has been the >"philosophy" of CGPM from the beginning. >... I don't dispute that function of these standards bodies. However, IMHO *official* changes should only be adopted when 1) they are made within the confines of adopted policies (if they exist, evidently... That's why I feel we should start working on this aspect of the SI system!); and 2) when a big enough improvement is achieved that would warrant unit's definition replacement. So, in essence, no opposition on my part concerning the need for 'updates', but that it be done in a "rigorous" manner (for lack of a better adjective...). Marcus Is your boss reading your email? ....Probably Keep your messages private by using Lycos Mail. Sign up today at http://mail.lycos.com
