# Reference request: Conformal Cyclic Cosmology

What knowledge-level is Penrose's "Cycles of Time" geared towards?

I'm looking for a comprehensive introduction to Conformal Cyclic Cosmology.

• It’s popsci, but it will not give you anything close to a comprehensive view of Penrose’s theory. Pop science both omits all the math actually needed to justify the theory, and blatantly ignores all of the many problems with the theory, in favor of dazzling the reader with quasi-mystical pronouncements about the true nature of the universe. If you want the full story, read Penrose’s own papers, and standard cosmology textbooks. – knzhou Sep 2 '18 at 2:09

I think the original presentation is:

Penrose, Causality, quantum theory and cosmology. In On Space and Time, ed. Shahn Majid, Cambridge University Press, Cambridge, 2008, pp. 141-195.

What knowledge-level is Penrose's "Cycles of Time" geared towards?

It's written for laypeople, but it's not an easy read if you lack quite a bit of background in relativity.

I think the original reference on the Weyl curvature hypothesis is:

R. Penrose, Singularities and time-asymmetry, in General Relativity: An Einstein Centenary Survey, edited by S. W. Hawking and W. Israel, (Cambridge University Press, Cambridge, 1979), p. 581, near p. 630

I'm looking for a comprehensive introduction to Conformal Cyclic Cosmology.

I don't think there is any other comprehensive introduction besides Cycles of Time. Keep in mind that CCC is no longer a viable theory.

• What makes it no longer viable? I hadn't heard of it until just yesterday when I stumbled upon this paper. I'm not qualified to judge it's legitimacy, I'm a math undergrad not a physicist, but it does have Penrose's and Meissner's names on it. – Eben Cowley Sep 2 '18 at 15:24
• I haven't been able to find the paper you mentioned on the internet, but I did come across a few arXiv articles claiming that the concentric annuli in the CMB are consistent with $\Lambda$CDM as well as CCC. Is this why the theory is no longer considered viable? – Eben Cowley Sep 2 '18 at 15:43