Recent content by Jaime Rudas

I only joined the forum recently, so I couldn't say if it's more or less moderate than in the past. However, I believe that strict moderation is one of the keys to PF's success. That said, I also think that some aspects of moderation can be frustrating, such as the limited opportunity to discuss...

The word 'ether' has had several meanings throughout the history of science. For example, regarding your question, look at what Einstein wrote in his book 'Sidelights on Relativity' (1920):

Sound doesn't propagate through the unobtainium.

Perhaps one of the first to analyze this situation was Paul Ehrenfest in his 1909 paper "Uniform rotation of rigid bodies and the theory of relativity" which is why it is now called the Ehrenfest paradox.

Yes, but that's what happens with all unsolved problems in science (inflation is one of them). The way science advances is precisely by devising hypotheses about their solution and testing them experimentally. Since these are still unresolved problems, it is perfectly logical that there is no...

Yes, it's true that Hawking conjectures that the exit from eternal inflation doesn't necessarily produce a multiverse, but I don't think that justifies claiming that the multiverse proposal is "much less formalized than it seems."

Do you have any references that support the idea that eternal inflation doesn't necessarily imply a multiverse?

Far less formalized in what sense? I ask because it doesn't seem to me that inflation with a multiverse is less formalized than, for example, inflation without a multiverse.

It's not the same to ask whether something could have happened as to ask whether it actually did happen. Moreover, the question seems to be aimed more at finding out whether this particular type of multiverse is among those described in the Wikipedia article.

The OP's not asking whether inflationary theory actually says a multiverse exists. He's asking whether different inflationary processes could have occurred in different regions, each giving rise to its own local universe. This is similar to the eternal inflation hypothesis that Tegmark includes...

As a supplement, this Andrei Linde's paper contains a good description of the eternal inflation hypothesis.

Yes, it's possible that it's flat, but we cannot determine that with certainty.

No, that's not the case. According to the Big Bang theory, if the universe is infinite, it has always been so.

Yes, when the uncertainty margins give us only positive or only negative values, we could be reasonably sure that the curvature is negative or positive (assuming homogeneity and isotropy, as @PeroK correctly points out). The measurements I cited were made from the cosmic microwave background...

Yes, that's what they currently point to because the best measurement of ##\Omega_{\kappa}## is ## 0.0007 \pm 0.0019##, but in the future, it could well be ## 0.00070 \pm 0.00019##, which would already point to a hyperbolic universe.