Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: flr on 13/04/2013 05:26:34

Title: Would a Universe comprised only of photons still have a time arrow?
Post by: flr on 13/04/2013 05:26:34
A universe made only of photons could have time-arrow?

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Title: Re: time arrow
Post by: yor_on on 13/04/2013 18:56:30
yes, as long as we imagine some dimensions for them to exist in they should have a arrow. And using light propagating they must have one in several senses. Using light as a clock they don't have a 'speed' in a normal sense, instead having a 'flickering existence', that should stop making sense at Planck scale to me. And in the last circumstance I might also say no, as each photon in such a case should need a rhythm, as well as a 'distance propagating', as we observe it, to create that arrow. So you can from this point of view imagine a pattern of photons, not 'visible' for the observer as representing something without a arrow, as it doesn't need to be a linear expression inside a 'common space' (propagation) but as the 'flicker' still should exist at a set rate 'c split down to Plank scale' you might want to call that one 'time' instead of a 'arrow', if so. It's a tricky one to me.