Project Gutenberg on Nostr: The metre is defined as the distance light travels in a vacuum in 1/299,792,458 of a ...
The metre is defined as the distance light travels in a vacuum in 1/299,792,458 of a second #OTD in 1983.
After the 2019 redefinition of the SI base units, this definition was rephrased to include the definition of a second in terms of the caesium frequency Δν_Cs. This series of amendments did not alter the size of the metre significantly, a change of 0.02% from the original value of exactly 40000 km, which also includes improvements in the accuracy of measuring the circumference.
#science
After the 2019 redefinition of the SI base units, this definition was rephrased to include the definition of a second in terms of the caesium frequency Δν_Cs. This series of amendments did not alter the size of the metre significantly, a change of 0.02% from the original value of exactly 40000 km, which also includes improvements in the accuracy of measuring the circumference.
#science