I came across the Edge website last week, whose home page declares the rather grand aim:
To arrive at the edge of the world's knowledge, seek out the most complex and sophisticated minds, put them in a room together, and have them ask each other the questions they are asking themselves.
It appears that the Edge asks an Annual Question, "What is the answer to life, the universe, and everything", that sort of thing, and then publishes the answers by the contributing illuminati.
The 2006 question is "What is your dangerous idea?".
So it was with some excitement that I started to read the assembled responses of the great and the good. Very interesting and well worth reading but, I have to say, the ideas expressed are, er, not very dangerous. Quite dangerous, one might say, but by and large not the sort of ideas that had me rushing to hide behind the sofa.
So, I hear you say, "what's your dangerous idea?".
Ok then, here goes.
I think that Newton's interpretation of his first law of motion was wrong and that there is no such thing as a force of gravity. Let me say right away that this is not my idea: it is the result of a lifetime's work by my friend Science Philosopher Viv Pope. But I have played a part in the development of this work, so I feel justified in evangelising about it.
Recall your school physics. Newton's first law of motion states that every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. In other words, that the 'natural' state of motion is in a straight line. Of course in an abstract sort of way this feels as if it is right. Perhaps that is why it has not been seriously challenged for the best part of 400 years (or it could be because Newton's first law has become so embedded in the way we think about the world that we simply accept it unquestioningly).
Consider an alternative first law of motion: the natural (force less) state of motion is orbital. I.e. that bodies continue to orbit unless an external force is applied. Now the Universe is full of orbital motion. From the micro-scale - electrons in orbit around nuclei, to the macro-scale - moons around planets, planets around stars, rotating galaxies etc. If this alternative first law is true, it would mean that we don't need to invent gravity to account for orbital motion. This appeals to me, not least because it leads to a simpler and more elegant explanation (and I like Occam's Razor). It would also explain why - despite vast effort and millions of dollars worth of research - no empirical evidence (gravity waves or gravity particles) has yet been found for how gravity propagates or acts at-a-distance. A common-sense objection to this idea is "well if there's no such thing as gravity what is it that sticks us to the surface of the earth - why don't we just float off?". The answer is (and you can show this with some pretty simple maths), that the natural (force less) orbital radius for you (given the mass of your body), is quite a long way towards the centre of the earth from where you now sit. So there is a force that means that you weigh something, it's just not a mysterious force of gravity but the real force exerted by the thing that restrains you from orbiting freely, i.e. the ground under your feet.
This has all been worked out in a good deal of detail by Viv Pope and mathematician Anthony Osborne, and its called the Pope Osborne Angular Momentum Synthesis, or POAMS.
Now that's what I call a dangerous idea.