Time travel has been a beloved topic of science fiction writers ever since HG Wells wrote about it in The Time Machine, published in 1895.

We tend to think of it as a far-out concept, and one that could never happen. Well, the reality is that time travel to the future has already happened. It’s a done deal.

Time travel to the past, meanwhile, is trickier, but should also be possible – in time! Just in case you’re wondering, however, it is not possible to travel to the past, and make changes.

To find out more about this mind-binding concept, and what is, and what isn’t possible I spoke to Professor Paul Davies, a scientist based at Arizona State University, who wrote a book on this subject called How to Build a Time Machine.

Prof Davies is a physicist, cosmologist, astrobiologist, science writer and founder of the Beyond: Center for Fundamental Concepts in Science, which looks at some of the biggest and most important questions facing science and mankind.

Listen:  Interview with Professor Paul Davies

Broadcast on Science Spinning on 103.2 Dublin City FM on 08.12.2011