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It is Earth's magnetic field that primarily protects us from solar flares.

by baking 10y ago

NamTaf 10y ago
Yes, I was talking about other radiation, eg: UV. That said, 5m of rock is way overkill for UV rays since they're blocked by opaque objects. It would be perhaps more helpful in its ability to weather small meteor impacts that routinely burn up in Earth's atmosphere. I understand that Earth's magnetic field is the primary defence against charged particles (eg: solar flares), but in saying that it's necessary to note that Mars' magnetic field is substantially less than Earth's, so rock would help there too. What I was trying to say in a round-about way is that it's not the atmosphere option that the parent postulated, because 5m of rock wouldn't, in my mind, produce enough of a secure boundary to contain an atmosphere in it. I could be wrong there, though - maybe it is secure enough in the right sediment!
- baking 10y ago
  Sorry, my point was that even if Mars had a thick atmosphere (after terraforming) you would still need underground bunkers for protection from solar flares and perhaps habitation. A thick roof is insufficient because the charged particles travel in a corkscrew path so you need thick shields on all sides. This is because it lacks a magnetic field and a large enough artificial one is impractical. EDIT: Also at last years trial, Musk said that a hyperloop design on Mars might not need tubes at all since the atmosphere is thin enough.
  - baking 10y ago
    The minimum pressure in the test track was 0.125 psi (teams using an air cushion could request a higher pressure and presumably if there was a leak the pressure could be higher than the minimum) while the air pressure on Mars is 0.087 psi.
  - NamTaf 10y ago
    Right, I misunderstood what you were saying. Also, yes, the hyperloop isn't directly relevant to Mars for that very reason - the atmosphere is annoyingly thin from a reentry point of view (enough that you have to protect against heating from it, but not enough that it can be used to bleed off all that velocity from orbit) but that means it's not really an issue if you want to push something fast through it. That said, I wasn't making any comment about the hyperloop itself rather the parent post's comments about why digging tunnels on Mars might be necessary. Not sure why my posts attracted downvotes though (not necessarily from you), but whatever.

It is Earth's magnetic field that primarily protects us from solar flares.

by baking 10y ago

It is Earth's magnetic field that primarily protects us from solar flares.

Yes, I was talking about other radiation, eg: UV. That said, 5m of rock is way overkill for UV rays since they're blocked by opaque objects. It would be perhaps more helpful in its ability to weather small meteor impacts that routinely burn up in Earth's atmosphere. I understand that Earth's magnetic field is the primary defence against charged particles (eg: solar flares), but in saying that it's necessary to note that Mars' magnetic field is substantially less than Earth's, so rock would help there too. What I was trying to say in a round-about way is that it's not the atmosphere option that the parent postulated, because 5m of rock wouldn't, in my mind, produce enough of a secure boundary to contain an atmosphere in it. I could be wrong there, though - maybe it is secure enough in the right sediment!

baking 10y ago
Sorry, my point was that even if Mars had a thick atmosphere (after terraforming) you would still need underground bunkers for protection from solar flares and perhaps habitation. A thick roof is insufficient because the charged particles travel in a corkscrew path so you need thick shields on all sides. This is because it lacks a magnetic field and a large enough artificial one is impractical. EDIT: Also at last years trial, Musk said that a hyperloop design on Mars might not need tubes at all since the atmosphere is thin enough.
- baking 10y ago
  The minimum pressure in the test track was 0.125 psi (teams using an air cushion could request a higher pressure and presumably if there was a leak the pressure could be higher than the minimum) while the air pressure on Mars is 0.087 psi.
- NamTaf 10y ago
  Right, I misunderstood what you were saying. Also, yes, the hyperloop isn't directly relevant to Mars for that very reason - the atmosphere is annoyingly thin from a reentry point of view (enough that you have to protect against heating from it, but not enough that it can be used to bleed off all that velocity from orbit) but that means it's not really an issue if you want to push something fast through it. That said, I wasn't making any comment about the hyperloop itself rather the parent post's comments about why digging tunnels on Mars might be necessary. Not sure why my posts attracted downvotes though (not necessarily from you), but whatever.