Empty space
Empty space may refer to: == Physics == Outer space, especially the relatively empty regions of the universe outside the atmospheres of celestial bodies Vacuum, a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure Free space, a perfect vacuum as expressed in the classical physics model Vacuum state, a perfect vacuum based on the quantum mechanical model In mathematical physics, the homogeneous equation may correspond to a physical theory formulated in empty space Void, empty space.