Ajit Pai @AjitPai
OTD in 1983, 17th General Conference on Weights and Measures redefined the meter as distance light travels in vacuum in 1/299,792,458 of a second—from 1,650,763.73 wavelengths of radiation in transition between specific quantum levels of krypton-86 atom. https://t.co/cDda2HExVV — PolitiTweet.org