Re: Solar sailing vs. laws of physics ?

From: Eliezer S. Yudkowsky (sentience@pobox.com)
Date: Thu Jul 03 2003 - 20:36:20 MDT

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    Damien Broderick wrote:
    > At 12:42 PM 7/3/03 -0500, Chuck wrote:
    >
    >>He talks of the Crookes radiometer - a device that has been shown to
    >>operate because of increased local gas pressure due to the heating of the
    >>blackened sides of the vanes.
    >
    > Not quite.
    >
    > http://math.ucr.edu/home/baez/physics/General/LightMill/light-mill.html

     From the above paper:

    "By the way. It is possible to measure radiation pressure using a more
    refined apparatus. To make it work you have to use a much better vacuum,
    suspend the vanes from fine fibers and coat the vanes with an inert glass
    to prevent out-gassing. When you succeed the vanes are deflected the
    other way as predicted by Maxwell. The experiment is very difficult but
    was first done successfully in 1901 by Pyotr Lebedev and also by Eenest
    Nichols and Gordon Hull."

    Light sails in the lab, in case anyone asks. 

    -- 
Eliezer S. Yudkowsky                          http://singinst.org/
Research Fellow, Singularity Institute for Artificial Intelligence

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