In the present study, the negative mass of the vacuum and the relationship between this negative mass and matter are investigated by discovering the common ground between vacuum and matter and formulating the repulsive force between the negative masses of the two matters. According to Newton’s second law, the mass will accelerate if the force is applied to it and the vector of acceleration is in the direction of and in line with the force vector. In the negative mass, applying the force to the negative mass, the acceleration vector is in line with force vector but has the opposite direction due to the negativity of the mass and this acceleration is the same gravitational acceleration. So, the reason for the gravity is discovered. Moreover, the superficial repulsive acceleration of stars and in continuation vacuum suction pressure on the surface of the celestial objects can be formulated and formulated negative massenergy
