Question: Edward, you are a physicist. What is your opinion on string theory? Bearing that opinion in mind, do you believe that it is an un provable theory? Or do you possibly prefer a different theory, like quantum loop gravity? I am interested to hear a real physicists opinion on the matter. Thanks for taking the time out of your schedule to read this. *dips top-hat in respect*

Edward Hughes answered on 17 Jun 2014:

Hi zestywolf,

Great question! At the moment I think that string theory can’t be proved, because it hasn’t produced predictions at low enough energies for us to test. But soon we’ll be able to test string theory models against the real world. My flatmate actually uses string theory to understand observations in space! So if his theory matches the data we get from telescopes that would be good evidence for string theory!

But string theory might be useful even if it’s wrong! Okay, that probably sounds weird, right? But the truth is, string theory gives us new maths that helps understand particle collisions. So while the whole theory might not be absolutely correct, the new maths can still help us work things out. I actually use ideas from string theory to study something completely different!

You mentioned loop quantum gravity. I’ve read a bit about it, and I think it’s very interesting.But the problem is it’s very very hard to do. Plus it doesn’t seem to produce the useful extra maths that string theory does. So it’s not so popular at the moment.

At the moment there are researchers trying to combine string theory and loop quantum gravity! I went to a talk a few weeks ago by somebody studying the overlap between the two ideas. Who knows – maybe together they’ll produce the correct theory!

Let me know if you want to know more.