Profitable Wonders James Le Fanu
The profoundness of human emotions is the sense of awe in the presence of, for want of a better word, genius – both at the work itself (the Mass in B Minor, the Sistine Chapel, The Tempest, etc), and the higher intelligence, so far beyond our comprehension, that created it.
There is, however, one very rare, perhaps unique, instance when we ordinary mortals can glimpse pure genius at work, captured in just eight words. The story is familiar enough.
From the time of Aristotle onwards, the regularity and order of the physical world – the undeviating sun, the movement of the planets across the heavens – was divinely ordained to be so.
The imaginative leap that displaced the inscrutability of God’s will, with an all explanatory physical law readily comprehensible to a class of ten-year olds, is described by Isaac Newton’s close friend, the physician and clergyman, Dr William Stukeley.
‘After dinner, the weather being warm, we went into the garden and drank tea under the shade of some apple trees
– only he and myself. Amidst other discourse, he told me it was in this circumstance when formerly the notion of gravitation came into his head.’
Newton described how, ‘in a contemplative mood’, observing an apple falling from the tree and wondering why it should drop ‘perpendicularly to the ground’ rather than moving sideways or upwards, he inferred there must be a ‘drawing power in matter’– a novel idea indeed.
But then come the eight words with which Newton revolutionised our understanding of the world. Talking of the strength of that attraction between objects, he said, ‘It must be in proportion to its quantity’. This could thus be defined in quantitative terms which, he would later show, could be expressed in the simplest of equations: the product of the mass of the material objects (say, the sun and earth), divided by the square of the distance between them.
And so it was that Newton transformed the divinely ordained world, into which he was born, into one governed by absolute, unchangeable, universal laws known to man.
As time has passed, so the explanatory power of Newton’s law of gravity has grown ever wider to touch virtually every aspect of human experience: the movement of the sun and stars (obviously); the ebb and flow of the tides; the cycle of the seasons; the shape of mountains sculpted by the movement of glaciers; the flow of rivers to the sea; and the size of living things from flea to whale – and us. For we could not be any bigger than we are without encountering the hazard, posed by gravity, of falling over.
But, and it is the most extraordinary thing, more than 300 years later, the means by which the powerful universal glue of gravity imposes order on the physical world remains unknown.
Newton himself was only too aware there had to be some physical means by which gravity exerts its influence over billions of miles of space. It was, he wrote, ‘an absurdity that no thinking man can ever fall into’, to suppose that gravity could ‘act at a distance through a vacuum without the mediation of anything else, by which that action and force may be conveyed’.
Perhaps, he speculated, space was suffused by an invisible ‘ether’, composed of very small particles by which the sun held the earth in its orbit; though this would mean that, over a long period, the movement of the planets would gradually slow down through the effects of friction.
In 1887, two American physicists, Albert Michelson and Edward Morley, discovered that there was no ‘ether’. Space is well-named – it is empty.
Put another way, Newton’s law of gravitation encompasses the sublime contradiction of being both the force that binds the universe’s far-flung matter into a coherent whole, allowing us to trace its history all the way back to its beginning and anticipate its end; and yet it is itself transcendent – it cannot be explained in material terms.