Question: would you encourage string theory or quantam loop theory?

Nathan Langford answered on 29 Jun 2012:

Hi hollisterchicken,

Quantum loop gravity theory and string theory are two different ways for trying to explain quantum physics and gravity using a single theory – to try and bring quantum theory and general relativity together in a consistent way. Unfortunately, I don’t really know much about these theories, since it is very much out of my field. But I can make a couple of comments.

Firstly, although it is a really difficult problem that people have been working on ever since Einstein came up with General Relativity and it is still unsolved today, I would still say that it is a very important problem. These are exactly the sorts of little inconsistencies that might point the way towards the next great physics revolution. There were similar annoying little problems with classical physics at the end of the 1800s that ended up opening the door towards the two great physics revolutions of the 20th century: quantum physics and the theory of relativity.

My second comment is that the key difficulty facing these new theories is that they need to come up with something testable – some sorts of predictions that we could actually test with experiments to try and provide evidence for whether the theory is right or wrong.

Hope this helps.
Cheers,
Nathan.