Oops. I should not have put a decimal point in the definition of the meter. It should be the distance traveled by light in 1/299 792 458 s. I'm letting myself be influenced by Brij's slow light.
Bill Potts, CMS Roseville, CA http://metric1.org [SI Navigator] >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On >Behalf Of Bill Potts >Sent: Tuesday, December 03, 2002 11:30 >To: U.S. Metric Association >Cc: [EMAIL PROTECTED] >Subject: [USMA:23750] Re: Dallasnews - kilogram > > >That's very slow light. > >I think you meant 299.792 456 2 Mm/s. The correct figure, by the way, is >299.792 458 Mm/s. The meter is defined as the distance traveled by light in >1/299.792 458 s. The official definition uses only that fraction and does >not attempt to rationalize it to a non-fraction. However, if it were >expressed as a non-fraction, it would be 3.335 640 95 ns, not 77.162 709 5 >ps. > >And what's a "pico-metric second?" The term is picosecond (ps). > >Bill Potts, CMS >Roseville, CA >http://metric1.org [SI Navigator] > >>-----Original Message----- >>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On >>Behalf Of Brij Bhushan Vij >>Sent: Tuesday, December 03, 2002 11:01 >>To: U.S. Metric Association >>Cc: [EMAIL PROTECTED] >>Subject: [USMA:23748] Re: Dallasnews - kilogram >> >> >>James and John Nichols, sirs: >>Refined value for velocity of light, c, was reported by Time, New York in >>their issue of 4 December 1972 as: 299.7924562 metre/second; and I >>attempted >>to define in term for measure of length Unit,METRE to be the distance >>traversed by light during 77.1627095 pico-metric second (Refer: The Metric >>Second; ISI Bulletin, Vol 25, No.4, 1973 April - a publication of >>Bureau of >>Indian Standards, New Delhi). >>Regards, >>Brij Bhushan Vij<[EMAIL PROTECTED]> >> >>>From: "James R. Frysinger" <[EMAIL PROTECTED]> >>>Reply-To: [EMAIL PROTECTED] >>>To: "U.S. Metric Association" <[EMAIL PROTECTED]> >>>Subject: [USMA:23741] Re: Dallasnews - kilogram >>>Date: Tue, 03 Dec 2002 09:44:08 -0500 >>> >>>John Nichols wrote: >>> > >>> > I thought someone found that c is not constant recently but is slowing >>>up >>> > like me. >>> > >>> > Just a thought. >>> >>> And still a fairly new hypothesis as I understand it, John. >>This is far >>>from being widely accepted. However, the change of other constants (such >>>as G, the gravitational constant) are fairly widely believed to be >>>changing very slowly over time; that comes from the general theory of >>>relativity and it relates to the cosmological constant that Einstein >>>suggested, then removed, then wished he hadn't. Put it up there with the >>>recent "dark energy" hypothesis. I think the two are related, actually. >>> >>> For practical purposes, though, the effect on SI units is >>vanishingly >>>small. We would be overly proud to consider that our standards will >>>stand for millions of years. >>> >>>Jim >>> >>>-- >>>James R. Frysinger >>>Lifetime Certified Advanced Metrication Specialist >>>Senior Member, IEEE >>> >>>http://www.cofc.edu/~frysingj >>>[EMAIL PROTECTED] >>>[EMAIL PROTECTED] >>> >>>Office: >>> Physics Lab Manager, Lecturer >>> Dept. of Physics and Astronomy >>> University/College of Charleston >>> 66 George Street >>> Charleston, SC 29424 >>> 843.953.7644 (phone) >>> 843.953.4824 (FAX) >>> >>>Home: >>> 10 Captiva Row >>> Charleston, SC 29407 >>> 843.225.0805 >> >> >>_________________________________________________________________ >>Add photos to your messages with MSN 8. Get 2 months FREE*. >>http://join.msn.com/?page=features/featuredemail >> >
