In 2015, the Chinese scholar Song Guanyi put forward the theory of repulsion interactions. The discovery of repulsion interactions opens up a new way to study the origin of the universe expansion. This paper systematically introduces

a. The mathematical expression and characteristics of the repulsion interaction

b. The energy source, existence state and energy magnitude of the repulsion interaction in the solar system

c. The existence evidence of the repulsion interaction observed on the earth

d. Throughout the universe, the magnitude of the energy level that drives the universe to expand and the characteristics of the expansion velocity of the stars (or galaxies) in the universe

The paper analyzed that the existence of the repulsion interaction provides necessary and sufficient conditions for the accelerated expansion of the whole universe, and the energy emitted by all stars in the universe is most likely to be the “dark energy” that the physical and astronomical circles are concerned about today.