Re: Nuclear Isomer Decay: A Possibility for Breakthrough Space

[Bernard L Cohen <blc+@pitt.edu>]

On Fri, 2 Apr 1999, John R. Laferriere 671-8316 wrote:

> I thought a radiometer operated by converting radiant energy to thermal
> energy (preferentially heating the blackened side of the vanes), which then
> was transfered to gas molecules within the partially evacuated bulb, which
> then "kicked" off the blackened side with more force than the gas molecules
> bouncing off the white sides of the vanes.  It seems more like conversion of
> radiant energy to thermal energy to kinetic energy (of gas molecules initially)
> rather than just a transfer of momentum.

	--This is dead wrong. Why would gas molecules kick the black side
more than the shiny side?
	 The photon hitting the black side is absorbed transferring its
momentum. But the photon hitting the shiny side is reflected backward,
transferring twice its momentum. Thus there is more momentum transferred
to the shiny side.


> 
> John Laferriere, CHP
> john.r.laferriere@dupontpharma.com
> 
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Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


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