Recent content by Jaime Rudas

In this regard, I seem to recall that a 2-sphere is a finite but unbounded space

Actually, no. As early as the mid-18th century, Immanuel Kant and Thomas Wright proposed the "island universes" hypothesis—the idea that nebulae were, in fact, collections of stars similar to the Milky Way. This idea captivated a significant number of scientists, as illustrated by the famous...

No, it isn't. According to the Big Bang theory, the universe could be either finite or infinite.

Could you cite reliable sources that state that?

How do you know it isn't?

Yes, when I mentioned the steady-state model in the original post, I assumed, perhaps mistakenly, that it would be understood that I was referring to a homogeneous and isotropic spacetime (without torsion!) that is expanding and has a positive density constant over time. Under these conditions...

I believe the issue stems from the historical sequence of events. In 1922, Friedman found solutions to Einstein's field equations under the assumption of a homogeneous and isotropic universe. In this context, he employed the metric that is now known as the FLRW metric. In 1927, Lemaître...

I'm not claiming that, Bonnor is claiming that that metric is the metric of the steady-state model

Bonnor does make the claim that that metric is the metric of the steady-state model, and at no point does he link this statement to McCrea's paper.

Yes, and I also said that Bonnor presents it as the metric that describes the steady-state model. What I have said about this is the following: I apologize for my poor writing. What I mean to say is that the FLRW metric describes homogeneous and isotropic spacetimes even when these spacetimes...

Bonnor's paper says: That metric is the FLRW metric when ##a(t)=-e^{2kt}## From the above, I conclude that the steady-state model is inconsistent with the Einstein's field equations and has an FLRW metric.

The principal contribution of Robertson and Walker was to establish that the metric previously introduced by Friedman and Lemaître is the most general metric compatible with a homogeneous and isotropic spacetime, as demonstrated in the original papers by Robertson (1935) and Walker (1937).

There is no contradiction; they are simply two different things. One is the FLRW metric, which is general for all homogeneous and isotropic spacetimes, and the other is the Friedman equations, which deal with the behavior of the scale factor for the particular case of spacetimes that satisfy...

I disagree. A homogeneous and isotropic spacetime is necessarily described by the FLRW metric, regardless of whether or not it satisfies Einstein's field equations. Bonnor's paper doesn't draws this conclusion. Bonnor's paper STARTS from the premise that the steady-state model metric is...

Equation 1.1 of the cited paper indicates that it is the FLRW metric with constant H.