I've been reading Nassim Nicholas Taleb's book The Black Swan which largely concerns the uncertainty of social and economic systems (and the futility of predicting outcome); the Black Swan being the rare event.

But in one of the chapters Taleb talks about the motion of atoms and probabilities of the trajectories of atoms. He illustrates using a coffee cup saying that the most likely atomic trajectories are such that they all cancel one another and the cup remains motionless on the table. But he cites there is the very rare possibility that all the atoms in the cup move in the same direction at the same time - and the coffee cup jumps off the table.

I have a basic understanding of entropy and Maxwell's Demon, but question that if Taleb's cited event were to ever happen would there be enough momentum, energy to actually cause the cup to fly off the table? I know atoms can move very fast, but then they don't tend to move very far for very long.

Is Taleb's illustration possible?

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    $\begingroup$ it's possible, but just about as unlikely as all of the air in my office suddenly moving to one corner, leaving me breathless. There are much better, more plausible "black swan" events that actually occur -- it's just that people don't anticipate them. Semper Paratus! $\endgroup$ – Peter Diehr Mar 5 '16 at 20:32
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    $\begingroup$ A machine to get all the atoms moving into the same direction is called a "rocket engine". If Nassim Nicholas Taleb would have thought about this just a little longer, he might have noticed that he was talking nonsense either way. If we install a rocket engine nozzle UP on the table, it will push down on the table and I really haven't seen a coffee cup that has its opening sideways. In no case will the center of gravity move. I think we are teaching this in high school, aren't we? The problem here isn't Maxwell's demon, it's a guy talking physical nonsense in what I would call a crappy book. $\endgroup$ – CuriousOne Mar 5 '16 at 20:33
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    $\begingroup$ In any case, "black swan events" are not the result if thermodynamic averages, they are the result of instabilities in non-linear systems with positive feedbacks. If I may suggest something... use that book as a door stop. $\endgroup$ – CuriousOne Mar 5 '16 at 20:37
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    $\begingroup$ @CuriousOne: Once again, that's an answer. It can't happen because momentum is conserved, and the coffee cup has no momentum to begin with. $\endgroup$ – ACuriousMind Mar 6 '16 at 10:50
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    $\begingroup$ Regarding the primarily opinion-based close vote: The day when it is a matter of opinion whether or not momentum is conserved will be a sad day for physics indeed. $\endgroup$ – ACuriousMind Mar 6 '16 at 10:51

I have seen some wet plastic coffee cups with very hot coffee poured inside moves horizontally. This happens not during the coffee is being poured but after a minute or two.

I theorized this is possibly due to trapped air between cup base and smooth table surface get expanded and create air cushion on which the cup slides until the air finds its way out from the water-seal.

But no way in this universe the cup can take off vertically because of all molecules strike. Its nonsense.


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