Discussion on the definition of basic physical units in space metrology

Abstract

Modem metrology theory are base on universally recognized truth of “the space is straight and flat in Euclid space”, “Mass of matter obeys conservation law”, and “light line is along straight”. But the General Relativity (GR) theory is shaking the root of modern metrology by “curve of space-time” and “gravitational red shift”. In large scale space out of the earth, in difference gravity potential, and considering the fourth state of matter — plasma, the basic units of time, length, electricity, temperature, and mass need research its definition. Frequency unit is influenced by gravitational red shift, time-keeping standard is whether redefined or to consider gravity potential. Light line is curved by gravity, whether length unit need redefine? Is the light-year unit true distance in space? Voltage unit relates to frequency unit by means of Josephson effect, and current unit relates to length unit, they are both affected by gravitational red shift. In space plasma, electrons and ions keep themselves temperature, because they have difference average kinetic energy. It is contrary to the definition of thermal temperature that the condition must be equilibrium and state of disorder and randomness. The famous formula E=mc2 told us that mass of matter is not conservation. Mass of matter could change with its energy. How to redefine mass unit in space metrology? The duty of space metrology is to unify unit system for large region in space. Here discuss some problems of definition of basic physical units in space metrology, and they are still open.