Just before this BBC podcast gets underway, here's something you may not know.

My name's Linda Davies and I Commission Podcasts for BBC Sounds.

As you'd expect, at the BBC we make podcasts of the very highest quality featuring the most knowledgeable experts and genuinely engaging voices.

What you may not know is that the BBC makes podcasts about all kinds of things like pop stars,

poltergeist, cricket, and conspiracy theories and that's just a few examples.

If you'd like to discover something a little bit unexpected, find your next podcast over at BBC Sounds.

Thanks for downloading the In Our Time Podcast.

For more details about In Our Time and for our terms of use, please go to BBC.co. UK forward slash radio for. I hope

you enjoy the program. Hello if you look up the word universe in the Oxford

English dictionary you'll find a following definition.

The whole have created or existing things regarded collectively, all things, including the earth,

the heavens and all the phenomena of space, considered as constituting a systematic whole.

That sounds fairly comprehensive as a description of everything, but for an increasing

number of physicists and cosmologists, the universe is not enough.

They talk of a multiverse, literally many

universes, to explain aspects of their theory, the character of the universe and the

riddle of our existence within it. Indeed, compared to the scope and complexity of

the multiverse, the whole of our known reality,

may be as a speck of sand upon a beach. But what might a multiverse be like? Why a physicist and

cosmologist increasingly interested in it and is it really scientific

to discuss the existence of universes we may never know anything about. With me to

discuss the multiverse of Faye Daka, reader in theoretical physics at

...