Dr Nick Read

Time and Tide

Time is the measure of things moving.  It’s like history; one bloody thing after another, but if nothing happens there is no time, ho history, nothing.  We know by determining the rate of decay of radioactivity in rocks that the earth came into being 4,558 million years ago.  This sounds a bit like Archbishop Usher, who calculated that the world was created 4,404 years ago. 

Time cannot be thought about with considering space as well.  Time is the fourth dimension.  We only need to go out and look at the night sky to see it happening.   The light that reaches us tonight set out from the nearest star 5 years ago and from the most distant galaxy, many thousand years ago.    

Isaac Newton thought time was always there; a God given fact, space was the constant stage upon which things happened, and light always travelled in straight lines. It was not until Albert Einstein that anyone dared to question these ‘facts’.  Einstein deduced that things that seemed to take place at the same time from an observer on earth, would occur at a different time if you were passing in a rocket. Events are perceived at the speed of light and if we were to pass through space near or at the speed of light, time would slow and stop.  Both time and space are relative to the observer.  Moreover light could ‘bend’.  The sun, 8 light minutes away probably did not exert an attraction on the earth but it warped space so that objects had to move in a fixed trajectory around the sun and light had a trajectory too. But it was Arthur Eddington that came up with the ‘proof’ by studying the light from stars behind a solar eclipse that light could appear to bend around massive objects  Eddington illustrated this by throwing a melon into the middle of a tautly held tablecloth and then rolling a walnut around the depression created.  Eureka!

If things are completely inert and nothing changes, then there is no time.  As soon as things change, there is time. So time and space are a continuum.  The approved wisdom states that time started with The Big Bang some 5000 billion years ago.  Since then matter, galaxies, stars, planets are speeding apart and getting colder and colder.  At one time, it was thought there would be a limit to the expansion and as mass  decelerated, gravitational forces would cause it to start to implode and then time would run backwards.  That’s what the equations would predict.  And how can we begin to understand what caused the big bang originally is it wasn’t some coalescence of mass and energy.  Nevertheless, physicists now seem convinced that there was a big bang and everything sped apart and is still accelerating and must eventually disappear.  Then nothing will change and time will cease again. Part of the evidence of the big bang came from the analysis of interference or white noise on television monitors.  I maybe an old cynic, but in astronomical physics as with everything else, what value evidence?              

So do we move through time or does time move through us?  We may be able to see time past, both in cosmological terms and what is fixed in memory, but we cannot see what is to come.  And there’s a problem, if time passes through us, then everything is preordained.  There is no free will.  To a certain extent that is true.  After the first few years of life, we create for ourselves a template for the way we will react, the choices we are likely to make, how our future is likely to be.  As the Jesuits said, give me the child at 7 years of age and I will show you the man.      

But doesn’t this all depend on the assumptions we make.  How do we know?  Physicists talk confidently about the distance of stars, how far galaxies are away, but how do they know?  Is there any independent measure of this that doesn’t depend on assumptions about time and space?   If space is curved like a doughnut,  could we not be looking at ourselves coming back?   Does Einsteinian geometry predict astronomical observations or does it just explain them?  Just as the design of a camera, the curvature of the lens, the shape of the aperture, determines our perception of the object, so image we have of our universe depends on the instruments by which we observe it, the assumptions of our  computers and the conceptual limits of our frontal cortices. The ancient Egyptians believed that the sun travelled across the sky every day and the moon did the same every night.  How much more satisfying life must have been then.