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Cryogenic Slug

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Thu, 2012-04-05 16:21

Prophet710 Prophet710's picture

Cryogenic Slug

Basically a strong magnetic field that encompasses a concentrated dose of Bose-Einstein Condensate, shot from something like the particle beam or plasma rifle. Possible?

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"And yet, across the gulf of space, minds immeasurably superior to ours regarded this Earth with envious eyes. And slowly, and surely, they drew their plans against us."

Fri, 2012-04-06 05:50

Arenamontanus Arenamontanus's picture

Re: Cryogenic Slug

I think you can do it, but it probably doesn't do what you think it does - freeze things. When you cool something down by throwing something at it, what happens is that the thrown stuff has a low temperature (heat will tend to flow to it) and a big thermal capacity (it takes a lot of energy to increase its temperature). It picks up heat energy, cooling the target. The end result is a weighted average (formula at the end of post). For example, a kilogram of 0 C water thrown at a 100 kilogram 37 C biomorph (both with specific thermal capacity 4.2 J/gK) will end up cooling the whole system to 36.6 C. If it was a kilogram of liquid nitrogen (~2 J/gK, -196 K temperature) the end result would be 35.9 C. If it was a kilogram of liquid hydrogen (~14 J/gK −252.87 C) the end temperature would be 27.6. Brr! ...but still not frozen solid. (In fact, since thermal conductivity is low most of the freezing will be at the surface) A freezing bullet must at least have a temperature of absolute zero. In order to chill the body to the freezing point it must have a mass times capacity of at least 57 - if it was like liquid hydrogen it would need to weigh at least 4 kilograms (and I think solid or metallic hydrogen has a lower heat capacity). I don't think there are any materials with better specific heat capacity, so the freezer bullet is not going to work in hard sf. Formula: if you add mass M1 of stuff with temperature T1 and specific thermal capacity C1 to a mass M2 with temp T2 and capacity C2, the end temperature of the whole thing will be (M1*C1*T1 + m2*T2*C2)/(M1*C1 + M2*C2)

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Fri, 2012-04-06 11:47

Kroeghe

Re: Cryogenic Slug

I guess you could squirt at people with white-blue fast drying resin with pretty much the visual effect I think you want, though. Fun!

Fri, 2012-04-06 15:15

Arenamontanus Arenamontanus's picture

Re: Cryogenic Slug

Kroeghe wrote:
I guess you could squirt at people with white-blue fast drying resin with pretty much the visual effect I think you want, though. Fun!

Yes, glue guns in EP ought to be really good. Thanks to the advanced materials science and nanotechnology you can make gels that turn hard on command (and dissolve on command). They could even do friend and foe distinction if you want to be fancy.

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Sat, 2012-04-07 11:02

Axel the Chimeric Axel the Chimeric's picture

Re: Cryogenic Slug

Fast-expanding foam materials would be great for capturing people. That said, spraying someone with liquid nitrogen would likely cause serious tissue damage. I know it's not the same as shooting them with a super-cooled slug, but I imagine getting a dose of it right in the face wouldn't be pleasant. Most smart vac-suits would probably be protected from that, though it may obscure your vision.

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Sat, 2012-04-07 11:53

Kroeghe

Re: Cryogenic Slug

I'm not so sure about the nitrogen thing. I've seen a guy who put his hand into liquid nitrogen for a few (2-3) seconds - there was absolutely no damage.* It seems the difference between the human body temperature and that of liquid nitrogen is so great that nitrogen evaporates on contact, creating something like an insulating layer of gas. I guess you could easily circumvent this effect by using a really large amount of nitrogen – but it would be something like using a fire-hose, but with nitrogen instead of water. Maybe not the most portable of weapons, maybe not the most accurate or practical one – but... hell. Although I’m not so sure if using cold gas is the best idea in Eclipse Phase. I’d guess most of the people living in space habitats would wear some kind of protective suit (considering how useful, cheap and practical they are, with smart materials and all) - as Axel said. And then there are synths and robots, whose bodies will not suffer any real damage from cold if only surface layers are exposed to it. I’d say – buy yourself a Freezer (EP core, p. 341- It should be called Foamer, really). You can’t go wrong with it. ---

Arenamontanus wrote:
They could even do friend and foe distinction if you want to be fancy.

I'd be fancy all over the place...;) --- *(Right after that he put a flower inside and held it there for about 6 or 8 seconds. The flower got completely frozen and shattered into tiny pieces afterwards.)

Sun, 2012-04-08 06:03

Arenamontanus Arenamontanus's picture

Re: Cryogenic Slug

Kroeghe wrote:
I'm not so sure about the nitrogen thing. I've seen a guy who put his hand into liquid nitrogen for a few (2-3) seconds - there was absolutely no damage.* It seems the difference between the human body temperature and that of liquid nitrogen is so great that nitrogen evaporates on contact, creating something like an insulating layer of gas. I guess you could easily circumvent this effect by using a really large amount of nitrogen – but it would be something like using a fire-hose, but with nitrogen instead of water. Maybe not the most portable of weapons, maybe not the most accurate or practical one – but... hell.

The Leidenfrost effect of getting a protective vapour layer only works under some conditions, like slow motion. There is also the problem that evaporation cools quite strongly. This cooling effect can be bigger than the effect of mixing with a cold material (think of putting some lukewarm water on your skin on a hot day - it cools you anyway, since it evaporates). Hydrogen and nitrogen have pretty hefty heats of evaporation.

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