“Many different phenomena in the Universe are time asymmetric and define an arrow of time that points in the same direction everywhere at all times. Attempts to explain how this arrow could arise from time-symmetric laws often invoke a ‘past hypothesis’: the initial condition with which the Universe came into existence must have been very special” – this is how Julian Barbour, Tim Koslowski, and Flavio Mercati open their paper titled “Identification of a gravitational arrow of time”.
In other words: for some funny reason once you make an omelette, you can’t go much backwards in terms of eggs used recreation. Time flows ruthlessly in one direction. Arrow of time stubbornly points into future. And the most common explanations of the phenomena focus on this very special moment of the beginning of the Universe. There must have been something unique, singular there that gave rise to time’s arrow over there/then, physicists say. They are not able say much more… At least at the moment.
Last year Julian Barbour, Tim Koslowski, and Flavio Mercati came across a completely different sort of explanation. They conclude that “the origin of time’s arrow is not necessarily to be sought in initial conditions but rather in the structure of the law which governs the Universe”.
I won’t tell you much more at the moment, because this is the very issue that “Bottom’s Dreams” is about. As you might have noticed Julian Barbour is one of the protagonists of Pioneers (trailer below), the documentary series committed by me, produced by POLITYKA weekly, and supported by Centre for Quantum Technologies, National University of Singapore. The movie will be released on DVD and VOD soon. It will explain everything you wanted to know about time. Well, almost everything.
Julian Barbour is a truly exceptional thinker, someone who for the last forty years has been following his own, independent scientific path. He is also the author of two groundbreaking books, “The Discovery of Dynamics: A Study from a Machian Point of View of the Discovery and the Structure of Dynamical Theories” and “The End of Time: The Next Revolution in Physics” – and a charming, friendly person, who always welcomes crude laymen like me.
Why am I writing this? Julian with his colleagues have been just awarded the Buchalter Cosmology Prize – for the very publication I mentioned above. It would be terribly patronizing for me to say: “I knew it!” So I will just say: Congratulations!
What’s interesting, we filmed “Bottom’s Dream” (trailer above) right after the paper was scheduled for publication in Physical Review Letters. It seems we pictured science in the making!
And here are some pictures that I took five or so years ago, during my first visit to South Newington in Oxfordshire, the Medieval origin village Julian spent happily most of his life in – a somewhat timeless piece of spacetime he has been drawing inspiration from.