Question: Do you think the idea of a graviton is stupid?

Alan Winfield answered on 18 Mar 2011:

No, I don’t think it’s a stupid idea. But I am very sceptical about gravitons. Since you ask the question I guess you know that gravitons are hypothesised (in other words proposed and predicted) elementary particles to try and account for gravity. Gravity is in fact a big puzzle to quantum physicists – and ever since Einstein physics has been trying to create a ‘unified field theory’ that ties together all of the fundamental forces of nature. The ‘standard model’ of quantum physics goes along way, but gravity (at the quantum level) remains unexplained.

There are two reasons that I’m sceptical about gravitons. The first is that we’ve now been looking for experimental evidence for gravitons, or gravity waves, for a long time and – as far as I know – they haven’t been found yet. It seems to me that if you look hard for something for long enough, and don’t find it, you really need to ask “does it really exist?”. The second reason I’m sceptical is that I’m not sure that gravity needs to be a fundamental force of nature at all. Whoa, you might say – that’s radical – of course gravity exists!! “What about Newton and his famous laws of motion?” Well it’s perfectly true of course that there’s something that makes you and me stick to the Earth and not float off into space. It’s true also that there’s something that makes the Moon orbit the Earth, and the Earth and other planets orbit the Sun. But there are other explanations for these real physical observations. One idea is that the thing we call gravity, in other words the real physical force that makes you weigh something, is actually a side effect of another physics law called the conservation of angular momentum. Here’s a blog post about a book that proposes this alternative theory, by Anthony Osborne and Vivian Pope http://alanwinfield.blogspot.com/2008/01/light-speed-gravitation-and-quantum.html

The problem is that it’s very very hard to get alternative theories like this taken seriously by scientists. Even though science is supposed to be open to the possibility that existing theories need to be revised if experiments suggest they may be flawed – when theories that mostly work well have been around for a long time they become so well established that anyone who questions them is regarded as a crank, or – to go back to your question – stupid.

So although I don’t think the idea of a graviton is stupid – I do think that science must always be open to the possibility that alternative ideas, even radical ones, could turn out to be very sensible indeed!