Vacuum energy is theorized to be the underlying background energy that exists everywhere across the universe. The term refers to a specific case of zero-point energy that is closely related to the quantum vacuum.
There is some disagreement as to the volume of space that this energy takes up, thus causing the cosmological constant problem. The conflict arises between the two methods of measurement. When referring to the upper limit of the cosmological constant, estimates show the vacuum energy of free space to be 10−9 joules per cubic meter. Alternatively, the field of quantum electrodynamics estimates a more significant, 10113 joules per cubic meter. This field is consistent with the Planck constant and the principle of the Lorentz covariance.
Observations in the effects of vacuum energy have been made in the Casimir effect, the Lamb shift, and spontaneous cosmic emissions. These observations have led cosmologists to believe that they play a role in the function and resulting behavior of the universe