The domestic time machine

Time remains one of life's most bizarre concepts.  We move around freely in three spatial directions, and can look wherever we like; and yet we are forced to move in only one direction in time, we cannot stop to admire the view, and must always look at where we came from, never where we are going. Which is probably why we bang our heads in life so often.

The ancients seem far less troubled by time than we are, perhaps because theirs was not a society obsessed with it.  Indeed, even the clocks were rudimentary, and the fundamental units were days, months and years.  Time as an independent entity, barely seemed to exist at all.  Similarly, for the great German philosopher Kant, time was regarded as a way of seeing things, a general property of the spectacles everybody's mind wore, along with the three dimensions of space.  It was only nearer our own era that time began to assume a richer form, and to assert some kind of independent existence.

Thus in the Special Theory of Relativity, born in the early years of the twentieth century, Einstein proposed the shocking idea of different times - relative ones, that is, depending upon your viewpoint.  Flowing from this was the famous Twins Paradox. Of two twins, one travels through space at an immensely great speed while the other stays on earth, When the space-travelling twin returns it turns out that he or she has aged a year or two, say, while the earthbound twin is fully twenty years older.  For the former, time has slowed down relative to the latter, and so the ageing process has slowed with it.  Nor is this mere theoretical speculation: highly accurate clocks have been taken on some of the later spaceflights and compared with an identical clock kept on earth.  The observed difference between the two is exactly that predicted by Einstein.
 
Against this background, and that of the even more disconcerting General Theory of Relativity which dissolves the hard distinction between time and space altogether, science fiction speculation about the possibility of time travel begins to look less fantastic.  The idea that we might be able to manipulate this strange thing called time is hard to grasp but not impossible to imagine. 

But really hard to believe may be the fact that time machines already exist.  This is not yet another top secret project that governments are keeping from us, but a device whose design is not only in the public domain, but whose implementation is to be found everywhere, and whose cost is only a few hundred pounds.  It is the refrigerator. 

Like the travelling twin in the paradox, food kept within a 'fridge ages more slowly - that is, does not decay or 'go off' as quickly. The 'fridge slows down time simply by reducing the temperature.  Nature has known of this trick for millions of years: hibernation is essentially about reducing the body temperature so as to lower the metabolic rate and with it the need for food.  Hibernating animals too are like the paradoxical twin, living life according to a different time.  This manifestation of one of science's great mysteries hardly demystifies it, but it does at least bring the whole issue much closer to home. In it, in fact.

(22.2.92)

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