Electron Orbits Dandelion


new internationalist
issue 213 - November 1990

[image, unknown]

[image, unknown] No teaching this morning. A compulsary, 'in-service' course on new technology for teachers. Fred's suspicious. What will new technology be able to do for history teachers? He has a soft spot for the glamour of new technology. What bothers him, though, is the science that lies behind it; he can't make head or tail of what he tries to read about it.

Electron orbits dandelion
Peter Stalker offers therapy to Fred - and anyone else who's
tried and failed to understand A Brief History of Time.1

Some of you may have put this book down feeling slightly faint, wondering how you can be so stupid while the rest of the world is so clever. Professor Stephen Hawking's popular guide to cosmology has sold more than a million copies in hardback around the world'. It is soon to appear in paperback and is to be a major film and TV series.

No need to repeat too many of the painful details here. The Cambridge professor's brain dances around such subatomic particles as leptons and anti-quarks and the possibility of infinitely curved space-time. A high-speed intellectual roller-coaster ride quite likely to toss you out of the car at the turn of the next page - or at best have you clinging on by the fingernails. Exhilarating stuff, but a lot of the excitement comes. I suspect, from the sense of sitting alongside someone who understands such ideas rather than really grasping them yourself.

Peter Stalker tests Newton's laws.
Photo: David Ransom

Science has held out the promise of giving the answer to 'life, the universe and everything'2 ever since ancient Greeks pondered on whether the earth was round or flat. Through Galileo and Newton in the seventeenth century and Einstein (and Hawking) in our own age, the details have become increasingly refined.

And technologists have applied scientific theories with some spectacular results: generating everything from nuclear power to moon rockets to holographs of the Eiffel Tower on Rice Krispies packets. So what does the baffled 'non-scientist' do if such awesome power seems beyond their grasp'? Well, keep awake for the next few minutes and you might derive a little comfort from knowing what scientists can and (more important) cannot do.

The first thing to bear in mind is that science ultimately never explains anything at all. It only describes what happens around us - which is frankly a lot less impressive. The description may be more precise than you or I might offer but it is a description for all that.

You will have realized, for example, that if you crunch your car into your neighbour's gatepost at 20 miles an hour you will do much more damage than if you nudge it at 10. An engineer will be more precise. She (or he) will point out that if you double the speed you quadruple the impact.

Now keep asking 'Why?'

Because the energy of a moving body is proportional to the square of the velocity.

Because it follows the equation: E=mv2/2 where E is the energy of the car's motion, v the velocity and m it's mass.

Because this follows from Newton's 'Second law of motion'.

Aha! So this is a 'law'. You may be tempted to stop asking questions in the face of such authority. But in fact you have received no explanation at all. The first answer repeats the original response in a more general way that would apply to other speeds too. The second reiterates this in a slightly different language using symbols instead of words. And the third tells you that it was Isaac Newton who wrote this equation down because it matched what happened every time he played billiards or threw apples around.

This and other scientific statements are so convincing (and get away with being called 'laws') because they appear to determine what will happen in the future. But they don't. All they do is describe what has happened in the past and guess that the pattern will repeat itself. It is just possible things will be different next time. You might try driving a car at a brick wall at a 100 miles an hour on the off chance of coming to no harm at all, but please make sure you have renewed your NI subscription first.

Technologists apply such scientific predictions to the construction of cars, or bricks or walls and will tell you how they interact. But ask them why they interact in this way and they will eventually pass you on to a scientist who (no matter how many equations they might try to confuse you with) in the end can only say 'Well, that's the way things are'.

In fact Newton's 'laws' are not universally applicable. Change the scale of measurement and they become completely unreliable. You could change the scale at which you look at the NI, for example. To you it just looks like paper. But a chemist, wondering how the rather fetching picture of myself (below) might be affected by being doused in nitric acid, would find it easier to understand the ensuing mess if she (or he) understood it as a collection of molecules of cellulose. And a physicist looking even more closely would try to picture these molecules of tennis player as clouds of electrons whirling round nuclei. Looked at more closely still the dissolved athlete could only be described with a set of equations which guessed where his component particles might be. At this level Newton's laws don't work at all, we have to talk in terms of 'quantum mechanics' which deals with all sorts of uncertainties and probabilities. Try crashing an electron into a gatepost and you might find that it decides of its own accord to orbit round the nearest dandelion.

The scientific language which describes this strange world can seem very alien. But it works the same way as ordinary language. It starts out with a familiar idea and then builds on it, making neater analogies and finer distinctions. So, if I asked you to describe paper to someone who had never seen it before, you might suggest they visualise it as a sort of hard, smooth 'cloth'.

Similarly molecules you might envision as clusters of tiny tennis balls. Electrons you could see as tiny planets orbiting round an even tinier sun. Remember though that paper is not cloth or tennis balls or planets. These are only descriptions. In the end paper is paper; which unfortunately is a bit of philosophical dead-end.

[image, unknown]
Photo: Jackie Morris

As one of the founders of quantum mechanics Niels Bohr put it: 'It is wrong to think that the task of physics is to find out how nature is. Physics concerns only what we can say about nature'.3

You probably feel quite happy talking about tennis balls or planets. But there are times when the analogies get stretched so far that the brain starts to lose contact with the original image. The latest subatomic theories, for example, say that we are all made up of infinitely thin pieces of string which may exist in ten dimensions. Now string you can imagine, even if 'infinitely thin' doesn't really bear thinking about. And three-dimensional space is something we can all understand - or make it four if you add time. But where are the other six? Well, just as you know you can move your hand with four 'degrees of freedom' in four dimensions so objects, considered in certain ways, have ten degrees of freedom.

You won't intuitively understand such things. Most scientists don't either, they just become familiar with manipulating their own abstract language as a useful way of organizing information. Nobel Laureate Richard Feynman is reassuring on this point: 'I think I can safely say that no-one understands quantum mechanics. Do not keep saying to yourself "But how can it be like that?" because you will get into a blind alley from which no-one has yet escaped.'

All of this mind-bending ambiguity might be unnerving especially to the non-scientist. But really you should celebrate such uncertainty because it helps undermine myths of scientific omniscience. Newton's laws and many others which followed, spurred scientists into a vision of a universe that might eventually be described in its entirety. So if we knew where any collection of molecules (like you) were now, and how they were moving, we might even use scientific laws to predict where you would go on your holidays and save you leafing through all those glossy brochures. Such 'determinism' now seems antiquated.

The sub-atomic world becomes so strange and 'unscientific' that some physicists like Fritjof Capra4 have been moved to consider the weird world of quarks and leptons in semi-mystical terms that combine the new physics with a holistic view of life in general. Such an approach is dismissed as 'rubbish' by scientists like Hawking. And while considering quantum mechanics from a Buddhist perspective can be very illuminating5, there's certainly no need to do so - it's extraordinary enough on its own terms.

The idea of a scientifically 'determined' universe has been further undermined by one of the newest branches of mathematics: 'Chaos' theory. This might sound like an accurate description of your holiday planning and did indeed arise out of a closely related activity: weather forecasting. Chaos theory has used high-speed computers to show how nature could create fantastic and beautiful objects, like snowflakes or leaves, from relatively simple repeated operations. But it has also illustrated that our future world is not just difficult to predict in practice: it is also theoretically impossible.

This is because the smallest changes in one place can have dramatic 'knock-on' effects elsewhere. So your turning a page of the NI magazine in Toronto, say, could so disturb the air as eventually to cause a hurricane in Melbourne (or vice-versa). But you could never predict that this was going to happen. This is not just because of the inordinate number of calculations involved. The central problem is that you could never measure the original position of the page with sufficient accuracy. In chaos terminology this is called: 'sensitivity to original conditions'. You might say you could measure its position to ten decimal places, but you could always then measure it to eleven and predict a completely different result; all the difference between a whirlwind knocking down someone's house and a single molecule of oxygen disappearing up their nose.

It is ironic that while scientific exploration has been producing incredible and exciting pictures of the world around us the technology it has spawned has had some depressing results - from atomic bombs to chlorofluorocarbons. But such destructiveness arises not from the sophistication of our technology but its crudity. While we can tinker with the genetics of life or with atomic fission we cannot operate with the sensitivity of naturally occurring processes, which might give us cause to consider that technology in certain areas should simply not be pursued at all.

Exploration of nature - human, artistic or cosmological - will undoubtedly continue. And while there are scientific minds like those of Stephen Hawking many steps ahead of us we will always want to listen to their stories of exploration - even if we can only get glimpses of what they are trying to describe.6

Stephen Hawking makes frequent references to what God might have been up to when designing the cosmos. Maybe She's laughing right now at even his attempts to disentangle it all.

Fred, I know you think you will never understand such things as long as you live. Well, maybe it is all a question of time. If you could wait just that little bit longer all might be revealed...

Peter Stalker is a former co-editor of the NI.

1 A Brief History of Time by Stephen Hawking, Bantam Books, 1988.
The answer to 'Life, the Universe and Everything' in '42' according to Douglas Adams in The Hitchhiker's Guide to the Galaxy.
3 Inventing Reality by Bruce Gregory, Wiley Science Editions 1990.
The Turning Point by Fritjof Capra, Flamingo, 1983.
The Dancing Wu Li Masters by Gary Zukae. First published in 1979, now available as a Rider paperoack 1990.
Cartoon History of Time by Kate Charlesworth and John Gribbin, Cardinal. 1990.

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