On 8/12/2014 1:39 AM, Gareth McCaughan wrote:
On 12/08/2014 05:14, James Propp wrote:
Say I have a jar full of water covered by a thin plate. Then I turn the jar upside down, holding the plate firmly against the lip of the jar to prevent water from spilling. Then I whisk away the plate so that instead of the plate pushing against the water, only the air beneath the jar is pushing upward.
Of course, the water will leave the jar. But what will the geometry of the process be? The water can't leave as a cylindrical slug; intuitively, it seems that the process has instability, so that spontaneous fingering in the air-water interface will break the initial cylindrical symmetry.
http://en.wikipedia.org/wiki/Rayleigh%E2%80%93Taylor_instability (I think).
Things are made of atoms. Atoms obey quantum mechanics. Quantum mechanics includes randomness. So symmetries get broken. Brent Meeker