“Yes, after all…

- •
**Roger Penrose**: “Friedmann-Lemaitre-Roberston-Walker (FLRW) [are] spatially homogenous and isotropic cosmological models. …each model starts with a Big Bang… for the different alternative choices of spatial curvature. In each case, the universe starts form a singularity—the so-called Big Bang—where spacetime curvatures become infinite and then it expands rapidly outwards.” [*The Road to Reality: A Complete Guide to the Laws of the Universe*(Vintage Books, 2005), 719.]

•**Stephen Hawking & George Ellis**: “We have seen there are singularities in any Roberston-Walker space-time in which µ > 0, p ≥ 0 and Λ is not too large… the fact that singularities do occur in such models gives an indication that the existence of singularities may be a property of all space-times which can be regarded as reasonable models of the universe.” [*The Large Scale Structure of Space-Time*(Cambridge, 1973), 142.]

• See also R. M. Wald,*General Relativity*(Chicago, 1984), 213-4. - To say the universe is not isotropic and homogenous is to say its not the same from all directions and all places. By way of response, however, [the Universe is expanding from a hot dense state], and the cosmic microwave background radiation is a sort of lingering afterglow. It is measured to be highly isotropic. In fact, thermal radiation temperature various by only a tenth of a thousandth of a kelvin. This is relevant because of the Ehlers-Geren-Sachs theorem[1] (and the Stoeger, Maarten, Ellis update)[2] which can use this data to prove we are therefore in an isotropic and homogenous FLRW spacetime. The relevant papers here are:

[1]Ehlers, J., Geren, P., Sachs, R. K., “Isotropic solutions of Einstein-Liouville equations.”*J. Math. Phys.*9, 1344 (1968)

[2]Stoeger, W. R.; Maartens, R; Ellis, George (2007), “Proving Almost-Homogeneity of the Universe: An Almost Ehlers-Geren-Sachs Theorem.”*Astrophys. J.*, 39: 1–5,

**(Big Bang Theory): General relativity (GR) is true, sufficiently accurately describing the full birth-growth of space.** Consider three evidences:

• …General relativity makes accurate predictions.This is relevant because “FLRW models with ordinary matter have a singularity at a finite time in the past.” [Christopher Smeenk, “Philosophy of Cosmology,” in Batterman (ed.),

• …Space in fact did expand from a hot-dense space.

• …Other evidences indicate: Physical reality (spacetime) began to exist, growing from a singularity.

**No**,

•…Space has an early quantum era (not FLRW); GR won’t apply.

•…Space is not isotropic & homogenous.^{2}

- More specifically and technically, this fate for a past tracing so-called “geodesic” is a degenerative symptom (“pathology”) associated with singularities. That is to say, while the theorem is not a singularity theorem—it entails no singularity—its conclusion is nevertheless evidentially symptomatic of a singularity, and either way fits cleanly with the longstanding most simple inflationary theory: the Standard Big Bang model. Consequently, “A model in which the inflationary phase has no end …naturally leads to this question: Can this model also be extended to the infinite past, avoiding in this way the problem of the initial singularity? …this is in fact not possible in future-eternal inflationary spacetimes as long as they obey some reasonable physical conditions: such models must necessarily possess initial singularities. …the fact that inflationary spacetimes are past incomplete forces one to address the question of what, if anything, came before. ["Eternal Inflation and the Initial Singularity," Physical Review Letters 72 (1994): 3305, 3307 (provided by Bill Craig)]

**(BGV Theorem): Any Universe eternally inflating/expanding on average requires infinitely-fast travel** Right?

• …consider Vilenkin's spacetraveler proof/illustration
^{1}

**So?** Couldn’t it simply be that… [All forthcoming]

•…Space contracts on average

•…Because of an infinite contraction phase

•…Space is static on average

•…Because of infinite cycling

•…Because of an infinite contraction phase (during time-reversal)

“No, after all…

**A beginningless universe (or multiverse) model is true.** This is relevant because the Standard Big Bang model under review here is not a past eternal model.

**Singularity-expansions (e.g. The Big Bang) aren’t events.** After all, “An event takes place within a space-time context. But the Big Bang has no space-time context; there is neither time prior to the Big Bang nor a space in which the Big Bang occurs.” (SEP).