Why Doesn't Time Flow Backwards? (Big Picture Ep. 1/5)
Thanks to Google Making and Science for supporting this series, and to Sean Carroll for collaborating on it! His book can be found here: http://www.penguinrandomhouse.com/books/316646/the-big-pictu...
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The basic laws of physics – things like F=ma, “gravity is inversely proportionalto the distance squared”, Schrodinger’s equation, and so on – don’t say anythingabout the direction of time.Sure, they relate what’s going on now to what happens next, and to what happened previously,but there’s no distinction between forwards and backwards in time.The past and future are on an equal footing, as far as the microscopic laws of physicsare concerned.In the macroscopic world, however, there is one rule that does have time going in onedirection only: the second law of thermodynamics.That says that any isolated system will tend towards increasing entropy, or disorder.Like how cold milk and hot coffee mix together into luke-warm coffee-milk, but will never
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The basic laws of physics – things like F=ma, “gravity is inversely proportionalto the distance squared”, Schrodinger’s equation, and so on – don’t say anythingabout the direction of time.Sure, they relate what’s going on now to what happens next, and to what happened previously,but there’s no distinction between forwards and backwards in time.The past and future are on an equal footing, as far as the microscopic laws of physicsare concerned.In the macroscopic world, however, there is one rule that does have time going in onedirection only: the second law of thermodynamics.That says that any isolated system will tend towards increasing entropy, or disorder.Like how cold milk and hot coffee mix together into luke-warm coffee-milk, but will never
