Hello gentlemen!

I recently discovered Sir Roger Penrose's conjecture about Conformal Cyclic Cosmology, and I find it very interesting. His claim that there are visible traces of the past aeon (former universe) in the CMB is a very intriguing, but I just can't wrap my head around how a cold, massless, radiation filled universe can turn into a hot dense singularity. Maybe someone here can explain it in layman's terms?

What do you think about the CCC theory?

Here's a 39 minute video where he explains it. But the step from old to new universe just doesn't click with me.

 

15 hours ago, QuantumT said:

but I just can't wrap my head around how a cold, massless, radiation filled universe can turn into a hot dense singularity

Due to the effects of gravity. Remember that in General Relativity, all forms of energy-momentum are sources of gravity, not just mass; so whether the universe contracts, expands, or stagnates just depends on the average energy-density, even if there is no conventional form of mass).

Note also that in this scenario there would be no singularity; contraction just turns into expansion below a certain minimum scale.