The cosmological constant is a theoretical term representing a constant energy density inherent to the vacuum of space. Its inclusion in the equations governing general relativity modifies the overall dynamics of the universe's expansion. While initially theorized to counteract the gravitational attraction acting on matter, contemporary measurements of the accelerating rate of the universe's expansion require the constant to possess a positive value, implying that vacuum energy exerts a repulsive gravitational force. The relationship between the theoretically predicted value of vacuum energy, derived from quantum mechanics, and the extremely small value required by astronomical observations remains one of the major unsolved problems in modern theoretical physics.