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I want to know if living on a ring-world with an outer velocity of 1200km/s would be survivable by humans or would you get baked from the constant collisions with stray hydrogen and space dust?

I'm specifying out a world for a role-playing game I'm DM-ing. Part of it is set on a Niven-esque ring-world (open-topped with side walls) that is 2AU in diameter.

I wanted to know how fast it would have to spin to generate 1g of apparent gravity, and it comes out to about 1200km/s which is very, very fast. According to wolfram alpha that is 2.2 times the escape velocity for our galaxy.

Would my regular human PC's be able to live on it? I imagine that collisions between interstellar dust and the atmosphere of the ringworld would emit a lot of radiation and heat. Without a magnetosphere would this be enough radiation to kill you?

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  • $\begingroup$ I think if you work the numbers you'll probably find that this is fairly inconsequential compared to the effects of cosmic rays. $\endgroup$
    – Gene
    Commented Dec 3, 2021 at 7:51
  • $\begingroup$ Wouldn't the tech for a ring world allow you to build/generate a magneto-tube of sorts? $\endgroup$
    – Lemming
    Commented Dec 3, 2021 at 10:47

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You are probably overthinking it. First of all, 1200 km/s is just 0.4% of c. A proton traveling at that speed has an energy of about 7 KeV, while the nuclear binding energy is on the range 1 to 9 MeV. Therefore there is not enough energy in the impact to trigger nuclear reactions.

Even if there was, there are many factors to keep into account, which lower the risk:

  • The atmosphere itself will attenuate the gamma rays produced by the impacts, and the impacts will happen far away from the location of the subject.
  • Last but not least, I have the feeling that most of the photons will be emitted not along the radial direction (because of the rotation), thus it will let the photons travel through more matter, again shifting it to less dangerous wavelengths.
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    $\begingroup$ "The atmosphere won't move coherently at the same speed of the ring:" ummm... why? 1200km/s to get 1g means a radius of 1.469e11m. For an atmosphere of 2e5m deep (in other words, 200km thick) the tangential speed between the (slower) upper atmosphere and the lower (faster) one is 0.000136% (that is 1.63m/s) - the variation of pressure due to temperature differential between two adjacent areas will produce higher "sea level" winds than that speed difference. So... what am I missing? $\endgroup$ Commented Dec 3, 2021 at 14:27
  • $\begingroup$ I would agree. With the particle density of space and the energy of particles at these speeds would be fairly insignificant. Cosmic rays that normally strike the Earth can be in the magnitudes of 50 GeV, and they have very little impact on the inhabitants. This massive structure would offer similar protects purely due to is mass. add an equivalently large power system and you maybe inadvertently providing some rudimentary magnetic field to also protect the surface. $\endgroup$
    – Sonvar
    Commented Dec 3, 2021 at 17:34

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