You know Ian … I am not really a conventional Scientist … so the answer you get from me may not be what you would get from most astronomers.
But my feeling about ‘Space’ and those vast distances is not that it is ’emptiness’, but that it is filled with light, energy, and Quantum Mechanical waves that represent probabilities of particles … there is nowhere that is ’empty’. So my own mental picture of it is actually more like C.S. Lewis’s vision of it in “Out of the Silent Planet” – a kind of living swirling energy-filled medium – part of all things, linked to us and to all creatures. I dont think Science has yet scratched the surface of what Space really is.
OK … from the co-writer of Bang ! this will probably raise some eyebrows …But my instincitve feeling is that, though Astrophysics does a great job in discovering patterns in the known Universe, there is more to this life and this Universe than material things.
All the very best