If I were a gnat

I sometimes wonder what it must be like to be a gnat.  Leaving aside the fact that as a gnat my brain would be too small to be able to answer the question, and assuming even more unreasonably that I knew what it felt like not to be a gnat and so could make comparisons, my main impression would presumably be like swimming in treacle.  For we tend to forget in such anthropomorphic fantasies that the world has a scale built into it, and that effectively the laws of physics would seem very different if we were a thousands times smaller – or bigger.

For example, ants are often cited as immensely strong for their size since they can lift many times their own weight.  Sometimes this is expressed in some such striking form as to say that if an ant were as big as a cow it could throw a combine harvester over its shoulder.  In fact it couldn’t, simply because its legs would buckle and break under the weight.  The strength of its body is defined by the material, and this does not change when you scale up the size.  So what is immensely strong when insect-small becomes as weak as any other organic material when the size of a human.

Another manifestation of this effect is to be found among the dinosaurs.  One reason why the very largest of them like the Brontosaurus are likely to have spent most of their time wallowing in shallow pools is that the stuff of their leg bones – which is the same in giant dinosaurs as it is in dainty gerbils – would probably have shattered under the immense pressure caused by propping up several dozen tons of Brontosaurus meat.  The animal simply would not have been viable without the auxiliary support obtained by partially floating in water.

The effects of scale can also be seen in much more homely surroundings.  When tiny children fall over with an apparently enormous impact, they often get up with almost no ill-effects.  Had an adult fallen in a similar way they might well have sustained serious damage.  In part this is due to the design of the child’s body: it is by nature very soft and supple, and the bones themselves are far less brittle.  But the scaling effect of physics also contributes: for children the impact is indeed less serious than for an adult simply because they are smaller.

Scaling can also be temporal.  Our personal sense is partly defined by the total time elapsed, or the total time remembered, which will obviously be less.  So, very roughly speaking, for a two-year-old child to wait six minutes is the equivalent of a twenty-year-old having to wait an hour.  Even though the scaling will not be exact, it does at least suggest why two-year-olds’ attention spans are so short.  Moreover, it also goes some way to explaining the converse slowing down of time for the old.  For an octogenarian an hour passing is like only fifteen minutes passing for a twenty-year-old, at least in terms of its relative weight in their life’s duration so far.

Thus whatever rulers and clocks try to tell us to the contrary, scales change.  We start near to the gnat, and finish near to the dinosaur.  Pity that in between we forget to make allowances for both.

(24.12.91)

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