4. The Total Span of Time

 

THE FUTURE OF TIME

by Sean O'Donnell, Ph.D.

Few people doubt that our knowledge of time in the centuries to come, will be very different from what passes for temporal understanding nowadays.
To know where you may be going however, it helps to realise where you have been coming from.
In these articles I will therefore strive for systematic and simplified exploration, of all major sectors of time knowledge as currently known to science. I will not address relatively trivial matters such as more efficient time management. Instead I will seek greater comprehension, and hopefully consolidation, of time's larger mystery overall.
This project derives from “The Mystery of Time”, an AdultEd course conducted by me at the National University of Ireland Galway (NUIG) – 1988 to 2,000 AD.

·         The Total Span of Time

on the MillimetreScale.

·         SUMMARY If one adopts a spatio-temporal scale of one millimetre per year, it becomes easier to appreciate the various high points in Universal history, since the first Big Bang event some 14 billion years ago.

In seeking to visualise time as a jigsaw of many pieces, one obvious first step must be to determine the extent of the whole. So what is the total extent or duration, of time in both past and future modes?
Firstly regarding time-past, its duration and high points can be clarified with some precision. That is of course presuming one accepts the Big Bang theory - that time, space and matter were all created in one singular First Event some 14 thousand, million years ago.
Nor can you logically ask what came before that moment, as people are often inclined to do. Indeed this aspect of Creation was first clarified by St. Augustine of Hippo around 400 AD. For 'before' is a time-descriptive adverb – and so is simply not applicable when there was no time.
Many have thought that this vast duration - of 14 billion years since the Big Bang and sometimes known as “deep time” - must be quite unimaginable to our everyday minds: after all we're accustomed to think in much lesser terms of a few centuries at most. Whence Charles Darwin in the Origin of Species maintained that “the mind cannot possibly grasp the full meaning of the term of even a million years”.

THE MILLIMETRE SCALE

However it seems to me that we needn't be quite so pessimistic as Darwin on this point. This is because the entire duration of the Universe can easily be reduced into familiar spans of Earth geography if we adopt what I'll term The Millimetre Scale. This very handy form of scaling was first used by me during my course on “The Mystery of Time” at the National University of Ireland, Galway, in 1989. Though posssibly others elsewhere may have conceived of it before or since.
In any case this scaled correlation between time and space measurements equates 1 year to a millimetre of distance. So that your maximum lifetime of 100 years will correspond to 100 millimetres (ten centimetres or four inches), 1,000 years to 1 metre, Darwin's million years to 1 kilometre and so on.
Imagine therefore that you have constructed some magic time machine which can travel back and forth through aeons past. Its special feature will be that it must also progress through just one millimetre of distance for every passing year.
Imagine also that you are about to start off from Greenwich Observatory in London, where global time reckoning was first formalised over a century ago. Finally your time machine must point south-eastward, so as to maximise convenient land-marks in terms of distance along the way.
First then you can set the controls of your time machine for rapid travel at hyper-speed, set to arrive in an instant right back at the birth of the Universe all those 14 billion years ago. In that case your time machine will also have transported you across 14,000 kilometres of distance – about as far from London as the north coast of Australia.
Next imagine reversing your controls, and setting them at a much slower pace, to come back up to the present from that far-off singularity in space-time. You can then travel back to Here-and-Now at Greenwich in more leisurely fashion, stopping to mark significant points in cosmic history along the way.
In that case you would have travelled over half-way back around the globe - about 8,000 kilometers which would equate to reaching Afghanistan on the way back from Australia - before observing our own familiar sun light up 6,000 million years ago.
Another 1400 kilometres of travel, or two-thirds of your journey back to Here-and-Now, would bring you to as far as Southern Russia. There you would see the earth finally solidify into a solid ball, that is about 4,600 million years ago.
A billion years later - or 1,000 kilometres nearer home – you would observe the first signs of primitive marine life appear. But you would still have to travel a further 3,000 kilometres, as far homewards as Northern France on your journey back to London, until plants began to colonise the land less than 500 million years ago.
By now likewise your time-ship would be entering the last 500 kilometres of its 14,000km journey through space and time – with a mere 4% left since you started at the first Big Bang event in far-off Australia. Only about the distance from Paris to London would remain, from your voyage of half-way round the globe.
But from now on you will have many more observation stops on this final stretch of your journey, since all significant life histories are crammed into this little recent span.
So the first amphibian animals crawled out onto land less than 400 kilometres away, one branch developing into those fearsome dinosaurs 150 kilometres afterwards. The North Atlantic Ocean began to open around the start of your final 100 kilometres away or 100 million years ago. And the dinosaurs disappeared just 60 kilometres away from your final Here-and-Now destination at Greenwich Observatory.

THE SPAN OF HUMANITY

The death of the dinosaurs also left ecological room for mammals to flourish, and of these some early hominids eventually began to walk upright. This happened some 4 million years ago, or just 4 kilometres from your journey's end. Later they learned to harness fire and develop proper speech, probably within the last one million years.
Much later again the first humans walked out of Africa to spread across the globe around 200,000 years ago. The total span of humanity as we know it is therefore crammed into the last 200 metres of that long journey from Australia.
Prehistoric times end and more definite human history commences very much later again. This happened with the change from nomadic habits to settled agriculture around 10,000 years ago. On the Millimetre Scale we have been using, this is just 10 metres away (about the width of a small classroom) from your final stop at Here–and-Now.
Another 5 metres and large-scale organisation of humanity into civilisation had been established – as the Pyramids of Ancient Egypt still testify.
True rationality however did not begin until Ancient Greece ca. 600 BC – just 2.6 metres away from the present in our year-per-millimetre terms. Nor was truly modern science able to start properly until about 500 years ago – just half the span of your arm from where you're sitting at Here-and-Now.......
And finally to this ever-growing journey you can add your own lifespan from birth in the recent past to death in the nearby future. It will equate to just 10 centimetres or 4 inches if you are lucky enough to live for a full century.

DURATION OF THE FUTURE ?

Millimetre scaling therefore provides us with a useful visualisation of all those years which have elapsed from the very first Big Bang event, in terms of a journey from Australia to London. Compared with time-past however the duration of time-future is a much less certain matter: whatever knowledge we may have of it consists of cosmic speculation in the main.
In fact about the only firm figure we have for time-future is that our parent Sun is a middle-aged star – and so destined to die out some 6 billion (6000 million) years ahead. Long before that it will have swelled into a great red giant star which will fill our entire horizon, burning our earth and all its surface into toast during its' lingering death throes.
Much much later again all the other stars in a still-growing Universe may also eventually have died out; even matter itself may fade away into nothingness uncountable trillions of years ahead.
Such estimates however are really just cosmic projections or speculations based on very slight or partial information gleaned from astronomy during the past century – and nobody doubts that there will be many more revisions ahead.
But if they are even remotely true, the good news is that the Universe as we know now is still very young. In fact it seems very much just a baby - in terms of cosmic time totality or its probable life-span....