Discussion on time rule out of the Earth

Time is a common metric across boundaries and cultures. To mitigate the influence of relativity effect on time measurement and time unification in wide areas out of the earth, a new time rule is brought about. The deep exploration of the Mars, the Jupiter and other asteroid in the past, employed an independent time system without considering time unification between different subsystems. For the vast space area, the current time rule which applies for the earth ground and the adjacent areas has to be optimized. In this paper, the meaning of time rules is introduced. With Regards to the outer space area, two time concepts depicting the relationship between time and space, and two modes to unify time are brought about. The absolute and relative time viewpoint are discussed here and a proposal to establish a space time keeping system is given.