Half a Pint of Science set out with the intention of making science accessible to anyone in the friendly and familiar atmosphere of the pub. Pleasingly, Chris Fewster’s talk on the science of time travel achieved just this. Speaking to a packed courtyard, almost 15 of whom had actually turned up for the event, Chris started with a dynamic re-enactment highlighting the well-known paradox of killing one’s own grandfather.
After a fun and light-hearted introduction Chris then began to delve deeper into the science looking at whether time travel could really be possible. Central to the debate is Einstein’s theory of special relativity, which states that time may pass differently for two objects depending on their speed relative to each other. In other words, if you have two clocks, one of which is stationary and another which is moving, the one which is moving will appear to run slow from the perspective of the stationary one. Perhaps more bizarrely still, this effect works the other way round as the stationary clock will also appear to run slow from the point of view of the moving one.
Based on these ideas, Einstein proposed the idea of the space-time continuum. Mathematically speaking, it is possible for the fabric of space-time to give rise to ‘closed time-like curves,’ which in turn would imply the possibility of time travel.
However, although time travel may be a mathematical possibility, the reality is not quite as simple, as the application of a little bit of logic gives rise to some bizarre effects. Firstly, ‘because history only happens once, any time travel that occurs must have a consistent story’; that is to say that however much you travel back in time, you cannot change history. Secondly, information can appear to come from nowhere. For example, imagine that at some point in the future, you wish to invent the Time Machine; it stands to reason that in this future your grandson may know how this works and could then return to the present in order to tell you exactly how you can make a Time Machine. But where did that knowledge originally come from?
Time travel is a complicated and at times mind-boggling subject, but in the rowdy atmosphere of the courtyard, and in spite of some interruptions from the large subwoofer system being set up next door, Chris Fewster did an excellent job of highlighting the key paradoxes and their implications. I would strongly urge anyone with even the slightest scientific inclinations to attend any half a pint of science event. They are fun, accessible and interesting, and the next events are at 7:30pm on Saturday the 25th as follows:
Green Chemistry – Glasshouse
Chemistry of Air – Courtyard
The Strange World of Quantum Mechanics – The Lounge