Do we live in a multiverses or a cyclic universe? Most cosmologists today accept the universe underwent a very rapid period of expansion called inflation. But inflation seems to lead to an infinite multiverse. Not everyone is happy with this multiverse ; and some cosmologists have sought alternatives to inflation. These alternative schemes are often cyclic. The chief proponent of one such cyclic model is 2020 Nobel Prize Winner Sir Roger Penrose. In this video the father of inflation Alan Guth and Sir Roger discuss the pros and cons of the inflationary multiverse versus Sir Roger's Conformal Cyclic Universe.
We highly recommend watching our film on eternal inflation with Alan Guth and colleagues
   • Before the Big Bang 4 : Eternal Infla...  
and our film on CCC with Roger Penrose and colleagues
   • Before the Big Bang 7: An Eternal Cyc...  
and other films in our Before the Big Bang Series which features Stephen Hawking, Alex Vilenkin and others.
   • Before the Big Bang 5: The No Boundar...