In order to cover the deficit of gravity, there are basically but two possibilities, each of which has its own advantages and disadvantages:

1. either dark matter exists. In this case, the 26.8% of the universe dedicated deficit in gravity, has to be assigned to the galaxies.
   • the advantage of this option is, that the paradigmatic status of the '3 + 1' spacetime of intergalactic space can be respected (I will get back to this in the 2nd point)).
   • the disadvantage of this option is that dark matter can only occur near the halos of galaxies, while such a restriction is probably not feasible in reality. Calculations with the Einstein equation produce a broad increase of gravity, but also at the level of solar systems, where it is not needed (§5.4).
2. or dark matter does not exist. In this case, the galaxies' percentage of the universe remains the same, while the gravity deficit (26.8% of the universe) has to be assigned to the part of intergalactic space.
   • the disadvantage of this option is, that it is an infringement on the purpose of Minkowski's '3 +1' spacetime, with all subsequent paradigmatic consequences. (From the Sphere Observer's viewpoint, after all, this spacetime has become "3 + 1" instead of "2 + 2", because curvature is negligibly small there (§5.3). This very slight curvature, however, now does have to be utilized.
   • the advantage of this option is, that the (original) einstein equation is correct again, because the halos now actually have to be assigned to intergalactic space. Curvature of the underlying spacelike Minkowski spacetime can only manifest itself at the edge of galaxies, seemingly drawing the outer stars into intergalactic space.
     

Assuming that gravity is an emergent property based on qubits, no distinction can be made between the abstract foundation of galaxies and the one of intergalactic space. In the case of emergence, gravity will exist everywhere in the universe, making option 2 the better choice.

Note 51 The latter, in fact, applies to spacetime shells as well. The larger the spacetime shells, the smaller the curvature, and the fewer gravity effects in the later world. In intergalactic space, the spacetime shells are infinitely large but remain, though minimally, curved.

Verlinde therefore assumes that the calculated deficit of gravity, 26.8% of the universe, must be a contribution from intergalactic space. Intergalactic space then comprises 68.3 + 26.8 = 95.1% of the universe (see figure below).

Note 52 Considering the fact that the halo of our galaxy has a diameter of about 200,000 light-years, one can easily image the sum of all halos being equal to 26.8% of our universe. In the image above, the halos of the galaxies therefore belong to intergalactic space. 

Continue to: 6.4.3. An intergalactic space with a lot of dark matter