I read the current definition of a meter is the distance light travels in 1/299,792,358 of a second. How did they come up with a number like that? Why not just call it 1/300,000,000? I also read the meter is 1/10,000,000th the distance from the north pole to the equator. How was that measured so accurately? --- news:// - complaints: ---

Not just any ten-millionth, but a ten-millionth of the quarter-meridian passing through _Paris_. Pure Greenwich envy. ;) Soon after their Revolution, the French defined the metre that way, and dispatched surveyors to measure it, despite the fact that both ends of that line are at sea. The idea promptly sank as a result (like so many subsequent French initiatives). More recently, even the SI folks have abandoned the guillotine and tried to reduce the impact of redefinitions on pre-existing equipment and scientific results. So when time and frequency became more accurate than any mechanical measurement, the definition of the metre was switched over to time and frequency. (And by the way it's 1/299,792,458.) ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net

OT: Length of the Meter?

May 16, 2014 21 Replies

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jurb6006 12 years ago

previously it was about 25.400051mm in USA and about 25.399956mm in the Brittish commnwealth. and previos to that different. "

You know this means war.

THE COLONIES WILL STRIKE AGAIN !

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Maynard A. Philbrook Jr. 12 years ago

Yeah, we need another TEA party!

Jamie

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