"The hole is the vacuous force which acts as an expansion pressure force exerted against an equal compression pressure force which is located in mass and culminates at its centres." [Russell to NYT - 1930 November 2]
See Also
beginning of expansion
Celestial
centripetal force
electric expansion
Expansion
Female Force
Law of Diffusion or Expansion
Radiation
Space
two-way compression-expansion sequence
Vacuum
Void