ugh...my "idiot twin" wrote this.
Harry On Fri, Oct 10, 2014 at 10:57 PM, H Veeder <[email protected]> wrote: > Another related thought experiment > > Consider the focusing of sunlight by a simple parabolic reflector. Why > doesn't that constitute a violation of the 2nd law of thermodynamics which > (according to one of the many equivalents formulations) says heat cannot > flow from a cold to hot region without an input of work. It is because the > reflector does work by changing the path of light photons. A reflector > attached to the ground does not appear to do any work because the bulk of > the Earth pushes back too. > > However imagine a number of parabolic reflectors assembled in a spherical > arrangement suspended inside a translucent bubble so the light is uniform > in all directions. > Each reflector focuses light but collectively the 2nd law is violated > because they do not appear to do any work since they all push against each > other and so do not move. > > > Harry > >
