Izvleček
Mednarodni sistem enot doživlja redefinicijo štirih osnovnih enot. Osnova za nove definicije so izbrane naravne konstante, ki so jim z redefinicijo pripisane tudi fiksne numerične vrednosti. S tem je v mednarodnem merskem sistemu odpravljen tudi zadnji artefakt – prakilogram. Pot do sprejetja redefinicije je zahtevala skoraj desetletje raziskav, ki so na koncu dale dovolj točne realizacije enot neposredno in zgolj glede na vrednosti naravnih konstant. Točnost realizacij enot po novi definiciji je enaka ali boljša od do sedaj veljavnih realizacij. Nove definicije enot so sicer abstraktnejše, omogočajo pa realizacijo enot kjerkoli in kadarkoli v nam znanem vesolju.
Abstract
Redefining the International System of Units (SI)
Four base units of the International System of Units are being redefined. The basis of the new definitions are selected physical constants which have been given fixed numerical values. With the redefinition, the definition of a kilogram will change, removing the last artefact – the International Prototype Kilogram – from the International System of Units. The path to the redefinition took almost a decade of research which in the end yielded sufficiently accurate realizations of the units directly and merely based on the values of universal constants in nature. The accuracy of unit realizations according to the new definition is equal or better than the currently accepted ones. Although the new definitions are more abstract, they provide stable values that remain unchanged everywhere and everywhen in the universe as-we-know-it.