A talk by Colin Stuart to the Orpington Astronomical Society on 24 January 2024
Report by Andrew Ramsay
Colin Stuart’s talk did not disappoint. Beginning with a series of mind twisting paradoxes: could you go back in time to stop catastrophes? could Quantum Leap star Sam Becket improve the wording of “Peggy Sue”? could you kill Hitler to stop plunging the world into war? – Stuart demonstrated the apparent impossibility of travelling backwards in time. He went on to propose the idea that events and people were fixed in time, both backwards and forwards – removing the illusion that we have free will.
Stuart illustrated the standard definitions of relativity, including the relationships between mass, time and space. We all have a space and time “budget”, he said, and we could use our space more quickly at the cost of time. Examples ranged from Usain Bolt to the Russian Astronaut Gennady Padalka, who spent an extraordinarily long time circling the earth. This resulted in crazy notions about the relative passage of time for heads and feet and the real requirement for GPS satellites to constantly have their internal clocks reset.
Turning to black holes and the curvature of space, Stuart explained how mathematics suggested that space could be bent sufficiently to enable “short cuts” – wormholes. He then revised our view of the pliability of time by posing questions of how far an astronaut of the future might travel back in time, further confounding preconceptions already established by his introduction.
Stuart dealt deftly with a series of questions from the audience and finished with a plug for his excellent books on the subject. All in all a most entertaining and mind-stretching evening.