Whether by coincidence or by some mental callisthenics of my own I was drawn to the subject of time in more than a couple of ways this week. First, I had the good fortune to listen to an episode of ‘The Infinite Monkey Cage’ a light-hearted look at scientific and philosophic subjects provided by the BBC. It can currently be located on the BBC Sounds website or app and has the rock star turned scientist Brian Cox in conversation with the Comedian Robin Ince and a panel of invited experts in the subject under discussion. It can be found here. The experts in this case were: Mark Gatiss (actor/comedian), Carlo Rovelli (theoretical physicist) and Fay Dowker (professor of theoretical physics at Imperial College London).
The discussion centred on whether time can be considered a universal constant or whether it is a purely subjective construct used for our convenience to measure or relate events in our consciousness. It was pointed out that time is not universally the same – as they put it, no universal ‘now’. Even on our tiny planet ‘now’ is different in Australia and Aberystwyth. We find it convenient to apportion our solar day into 24 hours of sixty minutes each containing sixty seconds. But if we were on Jupiter… Our ‘day’ would be just over 10 earth hours so we could not keep the same ‘time’ if we were to measure Jovian rotation for the purpose of planting crops there or arranging a dinner party with fellow Jovians.
The same issue arises when we consider travel. Heading to our nearest stellar neighbour Proxima Centauri would take 4.2 years at the speed of light. Bringing back pictures of our holiday on beach on a planet we found there would take another 4.2 years but when we got back our grandchildren’s grandchildren’s grandchildren would be too old to see the photographs while we would still be in our prime. I’ll come back to this ‘problem’ of interstellar travel later.
Carlo introduced the concept of the ‘Block Universe’ where time is not a continuum but all events; past, present and future; co-exist but where only the present is directly available to us experientially. Fay Dowker argued that only the past and present are available – the former through our memories – but that the future is, as yet, unwritten. The Block Universe is the current standard approach to theoretical physics as consistent with the theories of general and specific relativity proposed by Einstein. Generally it meets the needs of theories of quantum mechanics and quantum gravity. It has the advantage of being theoretically provable whereas Fay’s approach is what most people would accept as rational but which is unproved and unprovable at the moment.
That’s enough quantum to be going on with. The interesting question arising from this approach is the question of free will. If you take the Block Universe concept as given then the future is already written and free will doesn’t exist. Mark Gatiss offered the solution of the multiverse concept where all possible events and conclusions exist simultaneously but this didn’t seem to meet the approbation he might have expected. I find it odd to think that at any point I can choose to do one of many things and yet these choices have already been made. So I’m not a committed fan of the Block Universe… yet.
So where am I going with all this? Really, I’m trying to define the concept of time to my own satisfaction – and finding it immensely difficult. I am tempted to fall back on the concept of increasing entropy. Everything in the universe tends to decay into unavailable energy meaning the potential to do work. Perhaps our need to define time is being expressed wrongly. We should be considering measuring entropy as the passage of ‘time’ rather than inventing hours, minutes and seconds to inaccurately define increasing entropy. This, however, gets us into trouble with general relativity. It also brings into question the concept of individual memory. I know that on my seventh birthday I had chicken pox and got a ‘Champion the Wonder Horse’ annual as a present. Both ‘facts’ are concrete in my mind, I’m mentally scratching the sores and reading Champion’s wonderful adventures. But… I am the only person alive who ‘knows’ this. Is it a reality? Is it any more or less real than my belief at age six that I could actually fly? Both ‘facts’ are unprovable but equally fixed in my mind. So are both real in the Block Universe? Conceptually I am aware that the ability to fly is improbable but in the Block Universe it is as much a fact as chickenpox sores and calamine lotion.
I’m leading towards the concept of time travel. Could we create a situation that allows us to travel Terminator-like into the past? And if we could do this then because of the symmetry of physical laws could we not then also travel into the future? And if we could travel temporally then could we also travel to other physical locations in the universe instantaneously? This would allow the trip to Proxima Centauri to take place while still allowing me to show off my beach tan photos to my children. What is to stop us?
After the Six Nations Rugby match had finished and England had disappointingly failed to defeat Scotland at Twickenham, the second brush with temporality yesterday was the film ‘Next’ staring Nick Cage, Jessica Biel and Julianne Moore. Created in 2007, it largely missed the mainstream consciousness but it is an interesting exploration of the concept of time. IMDB gives it score of 6.2 so it isn’t total trash. The concept is simple, the plot more confused. Nick is a man with an unusual ability to see a few minutes into the future but only with regard to events which would affect him. He hides this ability by becoming a stage magician and casino shark. This brings him to the attention of the FBI who are trying to find a nuclear bomb about to explode somewhere in Los Angeles. The plot meanders and his abilities change from seeing two minutes into the future to more than two hours. Despite all this, the idea of being able to see into the future and avoid actions which might inconvenience him is both attractive and thought provoking.
Could it work in practice? In the Block Universe it would be straightforward. Combining it with a multiverse concept offers the ability to explore every possible outcome to an action and then pick the most beneficial. I’m planning my next visit to Ascot now!