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    Re: Liquid metals for artificial horizons.
    From: George Huxtable
    Date: 2002 Apr 1, 08:52 +0100

    Rodney Myrvaagnes said, about liquid metal for an artificial horizon-
    >You could trade the problems of mercury for adifferent set of challenges
    >by using NaK, the eutectic alloy of sodium and pottassium,
    >which is liqud at room tempereature. It is highly reactive and must be
    >kept from the atmosphere, so you horizon would have to have
    >an optically flat sealed roof with an inert atmosphere inside.
    >If you accidentally broke it, you would cause no longterm environmental
    >damage. In the short run, the extremely rapid production of
    >salts might get you a bad burn, and/or damage something else nearby.
    >I wouldn't try this at home myself, but if you work in a lab equipped to
    >handle such materials you could think about it.
    >Ha anyone tried making a prismatic horizon that dangles like a damped pendulum?
    There exist other alloys, less reactive than Sodium-Potassium. There's a
    mix of Gallium-Indium-Tin that's liquid at indoor room temperatures, though
    I am not sure how it would fare outside in winter. And I can't say how
    poisonous the constituents of that alloy might be. It develops a dullish
    tarnish on the surface, so is less bright a reflector than a
    recently-cleaned surface of Mercury, but is much lighter in weight. I have
    used it for other purposes, but not as a mirror.
    For what it's worth...
    George Huxtable.
    George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    Tel. 01865 820222 or (int.) +44 1865 820222.

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