We propose that the QCD vacuum pion tetrahedron condensate density should vary in space and should drop in the Kennan, Barger and Cowie (KBC) void for example in analogy to earth’s atmospheric density drop with elevation from earth. We propose to calculate the non-uniform pion tetrahedron condensate density and propose a formula for the gravitation acceleration based on the non-uniform pion tetrahedron condensate. The MOND acceleration change at the galaxies’ edges may be due to the pion tetrahedron condensate density drop. Gravity may be due to the underlying microscopic attraction between quarks and antiquarks which are part of the vacuum pion tetrahedron condensate. The major difference between classical and quantum mechanics may be due to the antimatter discovered by Dirac that may be part of the vacuum Aether. The central roles of antimatter and the non-uniform QCD vacuum that contains antimatter were not anticipated by general relativity and quantum mechanics. Their roles are not fully understood still and the discovery of the KBC giant voids and the possibility of a non-uniform pion tetrahedron condensate need further study