Endless inflation seems to be everywhere at the moment, including on this episode examining the nature of infinity. Brian and Robin dive through the back catalogue to discover there might be no limit to the number of parallel universes that exist. This leads to an argument between astronomer royal Lord Rees and comedy producer John Lloyd, who says the whole suggestion is total speculation. Even cosmologist Carlos Frenk can’t get his head round the idea, as he contemplates the suggestion that new big bangs may be happening all the time.

Episodes featured:Series 10: Before the Big BangSeries 6: Parallel UniversesSeries 21: Quantum WorldsSeries 9: To Infinity and BeyondSeries 10: Numbers Numbers Everywhere

New episodes will be released on Wednesdays, but if you’re in the UK, listen to new episodes, a week early, first on BBC Sounds: bbc.in/3K3Jzy

Producer: Marijke PetersExecutive Producer: Alexandra Feachem