The greatest innovation in physics was the realisation that the fundamental reality that underpins the world is totally unlike the familiar, everyday world of our senses. The first person to realise this was the Scottish physicist James Clerk Maxwell - arguably the most important physicist between Newton and Einstein. Up until his day physicists tried to model the world in terms of things they could see around them - people talked, for instance, of the ‘clockwork’ universe of Newton. Maxwell was the same and tried to explain, for instance, how a magnet transmitted a force to a piece of metal by imagining tiny invisible cogs turning in the space between the magnet and the metal. Finally, he gave up and threw away the cogs. Instead, he imagined ghostly electric and magnetic ‘force fields’ with no parallel in the everyday world permeating space. It was a seismic break with the past.
It liberated physics, leading to the quantum world - where atoms can be in two places at once; the world of general relativity where gravity is a warpage of four-dimensional space; and even today’s string theory, where the fundamental entity are tiny strings vibrating in an unimaginable space of 10 dimensions.
Marcus Chown is cosmology consultant of New Scientist and author of The Never-Ending Days Of Being Dead (Faber, 2007) (buy this book from Amazon(UK).