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> That's not what actually happened here (probably), but think of relatively heavy atoms like iron, ejected from a supernova at close to the speed of light. The

> That's not what actually happened here (probably), but think of relatively heavy atoms like iron, ejected from a supernova at close to the speed of light. They're not really "rays". Wow, I have to admit I always assumed cosmic rays to be gamma radiation but alpha particle radiation sounds a lot more scary. Does anyone happen to know if computers engineered for the space station or shuttles have already some built-in (memory)redundancy or magnetic shielding to account for damage by cosmic rays? I imagine a system crash of the life support systems in space would be devastating.

ben_w 5y ago
Radiation hardening is basically everything you can manage with the weight limit: https://en.wikipedia.org/wiki/Radiation_hardening https://en.wikipedia.org/wiki/Radiation_hardening IIRC nobody is currently using magnetic fields for shielding, I don’t know if that’s due to insufficient effectiveness, power consumption, or unwanted interactions e.g. with Earth’s magnetosphere.
- myself248 5y ago
  I've always wondered about that. Seems to me that if you can shield one side from the sun's heat and expose the other side to the cold of space, an MRI magnet's superconductors should be quite happy with the temperature. A big ol' magnet would be a pain to charge up once, and then provide long-term shielding.
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  - verall 5y ago
    MRIs are big electromagnets and they use big power and produce big heat. In space you have no convection so you must radiate away all of your heat which is challenging. Maybe you can make something better with superconductors that doesn't use much power, but I don't think it exists yet.
    - ben_w 5y ago
      Superconductors famously don’t produce heat. Putting a superconducting magnet in shade (though that includes from the Earth not just from Sol) will keep it cool once it gets cool. This is what the James Webb is going to be doing, though for non-superconducting reasons.
    - myself248 5y ago
      Um, what? The magnet in an MRI is a superconducting electromagnet. It needs power once, to charge it up, then you close the loop and it just sits there being a superconducting electromagnet. The only power used continuously is for cooling, which is to say, when ambient room heat leaks in, it has to be carried out again. The magnet itself does not produce heat; it has no electrical resistance because it is a superconductor.
adrian_b 5y ago
The vast majority of the cosmic radiation consists of protons, i.e. hydrogen ions. Light ions, e.g. of helium, lithium or boron are also relatively abundant and heavier ions are less abundant. There are also electrons, but in smaller quantities, because they can be captured by ions. The high speed protons collide with the atoms of the Earth atmosphere and the collisions generate a huge variety of particles, but most of them have a very short lifetime, so they decay before reaching ground level. At ground level, the cosmic radiation consists mostly of muons, because they have a longer lifetime, so they survive the travel from the upper atmosphere where they are generated, until ground level. Only extremely few of the particles from the primary cosmic radiation, i.e. protons, reach ground, because most are deflected by the magnetic field of the Earth and the remaining protons lose their energy in the collisions with atmosphere, by generating particles, which eventually decay into muons.

ben_w 5y ago

Radiation hardening is basically everything you can manage with the weight limit: https://en.wikipedia.org/wiki/Radiation_hardening https://en.wikipedia.org/wiki/Radiation_hardening IIRC nobody is currently using magnetic fields for shielding, I don’t know if that’s due to insufficient effectiveness, power consumption, or unwanted interactions e.g. with Earth’s magnetosphere.

myself248 5y ago
I've always wondered about that. Seems to me that if you can shield one side from the sun's heat and expose the other side to the cold of space, an MRI magnet's superconductors should be quite happy with the temperature. A big ol' magnet would be a pain to charge up once, and then provide long-term shielding.
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- verall 5y ago
  MRIs are big electromagnets and they use big power and produce big heat. In space you have no convection so you must radiate away all of your heat which is challenging. Maybe you can make something better with superconductors that doesn't use much power, but I don't think it exists yet.
  - ben_w 5y ago
    Superconductors famously don’t produce heat. Putting a superconducting magnet in shade (though that includes from the Earth not just from Sol) will keep it cool once it gets cool. This is what the James Webb is going to be doing, though for non-superconducting reasons.
  - myself248 5y ago
    Um, what? The magnet in an MRI is a superconducting electromagnet. It needs power once, to charge it up, then you close the loop and it just sits there being a superconducting electromagnet. The only power used continuously is for cooling, which is to say, when ambient room heat leaks in, it has to be carried out again. The magnet itself does not produce heat; it has no electrical resistance because it is a superconductor.

adrian_b 5y ago

The vast majority of the cosmic radiation consists of protons, i.e. hydrogen ions. Light ions, e.g. of helium, lithium or boron are also relatively abundant and heavier ions are less abundant. There are also electrons, but in smaller quantities, because they can be captured by ions. The high speed protons collide with the atoms of the Earth atmosphere and the collisions generate a huge variety of particles, but most of them have a very short lifetime, so they decay before reaching ground level. At ground level, the cosmic radiation consists mostly of muons, because they have a longer lifetime, so they survive the travel from the upper atmosphere where they are generated, until ground level. Only extremely few of the particles from the primary cosmic radiation, i.e. protons, reach ground, because most are deflected by the magnetic field of the Earth and the remaining protons lose their energy in the collisions with atmosphere, by generating particles, which eventually decay into muons.