thomblake comments on A cynical explanation for why rationalists worry about FAI - Less Wrong

25 Post author: aaronsw 04 August 2012 12:27PM

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Comment author: wedrifid 06 August 2012 06:21:23PM 1 point [-]

I thought that depleted uranium wrapped in paper was pretty much as safe as lead?

Really? As in... I can sleep with a cubic metre of the stuff under my bed and not expect to get cancer within a decade or two?

Comment author: thomblake 06 August 2012 06:42:39PM 2 points [-]

For fun: read the parent as implying that wedrifid has slept on top of a cubic meter of lead for decades.

Comment author: wedrifid 06 August 2012 06:58:34PM *  2 points [-]

For fun: read the parent as implying that wedrifid has slept on top of a cubic meter of lead for decades.

It's so soft! There is no other metal that I've slept on for decades that is more comfortable than lead.

I haven't tried a water bed filled with mercury yet. That actually has potential. The extra mass would absorb the impact or rapid movement of a human more smoothly while maintaining malleable fluidity over a slightly longer timescale. Plus if you attach a glass tube near the head of the bed you can calculate your weight based off changes in mmHg!

Comment author: gwern 06 August 2012 09:11:51PM 4 points [-]

I used to think that my mercury bed was a bad idea and mad as a hatter. But then I gave it a fair try for a few months, and boy did my mind change!

Comment author: Decius 06 August 2012 10:23:36PM 0 points [-]

It's not the mass, it's the viscosity. The higher density would result in a 'firmer' feel, since less immersion would be needed for the same amount of buoyant force.

A more reasonable option might be Gallium-which would be firm on initial contact, but then liquefy.

Comment author: wedrifid 06 August 2012 10:34:06PM 1 point [-]

It's not the mass, it's the viscosity.

No, really, it's both. I edited out out viscosity since either would be sufficient and I happened to be certain about mass but merely confident about viscosity.

Comment author: Decius 07 August 2012 12:43:34AM 0 points [-]

I assume that the primary mechanism by which mass absorbs impact would be inertia.

Malleable is a property that liquids don't have, so what did you mean by 'maintaining malleable fluidity' that doesn't also result from having the liquid in a closed container with some airspace and some elasticity? How would more inertia help absorb impact (spread the impulse out over a longer period of time)?

Comment author: [deleted] 06 August 2012 10:19:56PM *  0 points [-]

That's actually a neat idea. You could use gallium/indium/tin alloy perhaps. Would be easily the most expensive fluid bed.