The Meter Is Defined As The Distance Travelled By Light In 1/299792458 Second.Why Did The People Not Choose Some Easier Value Such As 1/30000000 Second? Why Not 1 Second?


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David Hinners Profile
David Hinners answered
The definition uses such an odd number because it was designed to refine an already existing definition. The original definition used a nice, round number - the distance from the equator to one of the poles divided by 10,000,000. However, that distance was difficult to measure accurately, and as better measurements were taken, it would have had the effect of changing the length of a standard meter.

To avoid that problem, the meter was redefined as the distance between two scribed marks on a special platinum-iridium bar kept in France, near Paris, at the Bureau International des Poids et Mesures. (In English that translates to International Bureau of Weights and Measures.)

Since then, the ability to measure distances using such things as lasers has gotten more accurate than the ability to duplicate the marks on a bar. So, in order to make sure that everyone is using the same definition of a meter, the new standard meter is defined in terms of the speed of light.
Anonymous Profile
Anonymous answered
The length of the Meter was decided in 1797, and scientists didn't have a good idea of the speed of light until 1983, and didn't even understand the importance of the speed before Einstein. The fact that the speed of light is close to the easy to remember number 30000000 m/s is pure coincidence. Changing the length of a meter to make the number easier to remember would mean every ruler, road sign, speedometer, physics book, etc would need to be replaced, so its not going to happen.

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