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Hello, when contemplating the vacuum of space in the 17th century,

the physicist Blais Pascal claimed,

the eternal silence of these infinite spaces

fills me with dread.

But we're here round today Pascal's anguish might have been assuaged

for the vacuum of space, while certainly silent and possibly infinite, is by no means empty.

It's a seething mass of particles, of

interactions, forces and energy. To study it undermines the distinction

between something and nothing. But by examining the nature of the vacuum, we get closer to

understanding the fabric of reality and the expansion of the universe.

With me to discuss the vacuum of space at Jocelyn Bell-Burnell,

visiting professor in astrophysics at Oxford University,

Ruth Gregory, Professor of Theoretical Physics at Durham University,

and Frank Close, Professor of Physics at Exeter College, University of Oxford.

Frank Close, the idea of nothing was something which preoccupied the Greeks.

Yes, Aristotle, I think, decided that there was no such thing as nothing and the idea that nature

abhorres a vacuum which is a phrase that everybody's heard but probably what

does it actually mean held sway for 2,000 years.

And in the Middle Ages, there was a lot of religious conflict as well.

The idea that God would make nothing was regarded as heresy.

...