Annu. Rev. Astron. Astrophys. 1988. 26: 561-630 Copyright © 1988 by Annual Reviews. All rights reserved

9.4. The Time Test of the Standard Model

Of the four tests discussed earlier [N(z), N(m), m(z), (z)], the time test for q₀ is the only experiment devoid of direct evolutionary effects, making it the most promising (at the moment) to find q₀ (or ₀ if ₀ = 0). Adopting H₀ = 42 ± 11 km s^-1 Mpc^-1 and T₀ = 14.9 ± 2 Gyr (Sandage 1988a) gives

which is the close to the required 2/3 if ₀ = + 1. The formal solution is

(57)

where the formal errors depend mostly on the large assigned error to H₀. If we assign a smaller error and adopt H₀ = 42 ± 6, then

Although the errors are still very large, there is now, for the first time, the astronomical possibility that ₀ = 1 exactly, required by the inflationary cosmology of Grand Unification. It must be emphasized, however, that no claim is made here from the available data that ₀ is 1, only that it is now possible that it could be so if H₀ can be reduced, as here, to 42 and T₀ shortened by ~ 15% below 17 Gyr. This does give agreement with the inflationary prediction from the time-scale test, whereas the earlier literature values on ages did not.

Equation 31 shows that the price to be paid is to believe that at least 99% of the matter in the Universe is dark. Such dark matter has not yet been detected, and its existence must remain an article of faith for the true believer in the standard model and its covering theory of Grand Unification.