You know, what with the recent passing of Halloween, I thought I’d try my hand at a little horror story-telling of my own. It is a chilling tale about a demon, passed down through the ages in hushed tone and bated breath. Few dare to become too invested, and even the most intrepid minds find their dreams being haunted by this eerie creature. Those that are feint of heart, be warned…
Last week I explored the idea of time irreversibility in the universe. Our laws of physics are invariant over a T-transformation; whatever a particle does is not affected by whether it is moving forwards or backwards in time. Yet why do we still see an obvious ‘arrow of time’ in real life?
…which of the symmetries hold at all? The universe is a curious place and cosmologists endeavour to contain this curiosity into one theory. Or maybe two, if they’re unlucky.
If there’s anything that physicists love, it’s obeying laws.