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just_another_person@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

The basis for what you’re saying is that water is some kind of magic shield the reflects radiation, which is not a thing.

At best, if you’re talking about lining the hull of a spacecraft and expecting that to work, that’s not a thing either because of the water is taking on any extra mass of any kind, it would obviously expand. Water in its purest form would have to take on mass to “absorb” radiation, expanding a hull and destroying it over time. If you left room in there for expansion, you’d die on exit or reentry of atmosphere without freezing it.

The only way you can reflect radiation without absorbing something is by denying it entry. Water doesn’t do that.

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skillissuer@discuss.tchncs.de ⁨3⁩ ⁨weeks⁩ ago
water does not expand upon irradiation, what the fuck are you talking about. you can’t reflect high energy protons (what would be important in radiation in interplanetary travel) you can only either absorb them or let them pass, there’s no third option, same for anything above uv and electrons

to a first approximation (rather good one at that) (for gammas) absorption is proportional to how much mass per area unit is used as a barrier. 1 g/cm^2 of water is just as good barrier as 1 g/cm^2 of lead or steel. this means that you can absolutely use completely normal, regular potable water as a radiation shield

Water in its purest form would have to take on mass to “absorb” radiation, expanding a hull and destroying it over time.

i’m not even sure what it’s supposed to mean, unless your understanding of ionizing radiation is uncut nonsense

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- just_another_person@lemmy.world ⁨3⁩ ⁨weeks⁩ ago
  Okay, so where do the neutrons go in your head? Gotta go somewhere.
  
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  - skillissuer@discuss.tchncs.de ⁨3⁩ ⁨weeks⁩ ago
    what neutrons? we’re talking about shielding of spacecraft moving out of earth’s magnetosphere, not a spacecraft travelling through core of active nuclear reactor
    
    the kind of radiation that is relevant are high energy protons (and alphas and electrons, with a sprinkle of heavier nuclei) from sun, mostly. there’s no relevant source of neutrons
    
    (and incidentally water is pretty good at absorbing neutrons too)
    
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    just_another_person@lemmy.world ⁨3⁩ ⁨weeks⁩ ago
    I think you are confused about how radiants work on Earth vs Space.
    
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