3 ms·

Mars' famous dust storms aren't so good at causing damage, because the air's really, really thin, so they can't pick up heavy particles even with high wind spee

Mars' famous dust storms aren't so good at causing damage, because the air's really, really thin, so they can't pick up heavy particles even with high wind speeds. A serious problem if you need to keep grit out of fine machinery or electronics, not so much if you're worried about erosion (I mean, yeah, eventually it'd be a problem, but it's slow-motion compared to the erosion of something exposed to sand storms on Earth) I guess it could eventually get buried, but I'd expect that to also be a slow process on most parts of the planet, for similar reasons. The only forces seriously driving weathering on the planet are radiation and wind—the radiation's pretty bad but not a problem for metal + some rocks that were already on the surface, at least over a span of a couple decades, and the wind just can't deliver much force because the atmosphere's so very thin (that's also why it's fairly difficult to fly on Mars).

somenameforme 3y ago
As a fun anecdote this is one of the very few things that was completely faked in "The Martian" - book and movie alike, which is otherwise a hard sci-fi book. I think it's quite telling when your instigator for a disaster scenario on Mars has to be faked! Well at least intentionally faked. It turns out Martian regolith/soil is also much more moist than expected so getting water will be relatively easy, but at the time of the book this wasn't known!
- generalizations 3y ago
  To be fair, it wasn't even the only disaster scenario in the movie - but it's very difficult to come up with a realistic scenario where someone would get left behind with a livable hab.
  - jenadine 3y ago
    How about a fight between members of the crew causing the mission to be cancelled, and one of the member left for dead after a violent interaction with another member who then lie about it.
- omoikane 3y ago
  > The Martian The thin atmosphere bit is acknowledged by the author, you can watch his talk here around 32:35: I just want to be as accurate as I possibly could. There are a few places that are inaccurate. The biggest place that's inaccurate is right at the beginning. Don't tell anybody, but if you're in a dust storm on Mars, you're not even going to feel it. Mars' atmosphere is less than 1% of Earth's. So a 150 kilometer an hour wind would feel like about 1 kilometer an hour wind does on Earth. It wouldn't do any damage to anything. https://youtu.be/gMfuLtjgzA8?si=8aZUEizDWuBhnaJg&t=1958 https://youtu.be/gMfuLtjgzA8?si=8aZUEizDWuBhnaJg&t=1958 There is another clarification later at 35:34 saying the dust storm is basically like talcum powder.
  - rob74 3y ago
    Well yeah, he needed some sort of catastrophic event to set the rest of the story in motion, and a huge dust storm which forces an evacuation and then separates Mark Watney from the rest of the crew was just the thing, so he added it although he was fully aware that storms don't work that way on Mars...
  - danielvf 3y ago
    I don't know anything about mars, but I've messed with windmill math. This really doesn't make sense to me. A 150 mph wind in 1% atmosphere should be a way stronger a 1 mph wind on earth? You know the old formula, force = mass * velocity * velocity But with wind and water the more velocity, the more mass you get hit with in the same amount of time, so we get to multiply by velocity again. wind force = mass * velocity * velocity * velocity (This formula is why people die in fast moving water.) So a Mars 150mph wind (0.01 * 150 * 150 * 150) would have 34,000 times more force than a 1mph wind on earth. Which works out to around a 32 mph earth wind.
    - deleted 3y ago
      [deleted]
    - MathMonkeyMan 3y ago
      mass * velocity * velocity has units of energy. It's twice the kinetic energy.
- throwbadubadu 3y ago
  > which is otherwise a hard sci-fi book Hard sci-fi is still a story and doesn't need to nail everything. And it had other pretty "unrealistic" moments that put me more off than the storm. Foremost, how they fixed the missed orbital rendezvous, no never going to happen that way. Or that they could just revert their home flight and go once more back and back again, how much delta-v would that be, never could have had that much extra fuel at least in that world... and other minor things, but still superb story.
  - NotSammyHagar 3y ago
    I thought in the martian they just looped the earth to go back, and then there was the supply rocket problem. They didn't do anything silly like just use the rocket to turn around and go straight back iirc.
- jo38j8o3jo8rj3 3y ago
  I remember some nasa administrator laughing about that at a conference. "So at the end of the movie the atmosphere is so thin that he can fly through it at thousands of miles per hour without harm, but at the beginning a sandstorm at hundreds of miles per hour destroys the ship? Also the spacesuits ... no."

somenameforme 3y ago

As a fun anecdote this is one of the very few things that was completely faked in "The Martian" - book and movie alike, which is otherwise a hard sci-fi book. I think it's quite telling when your instigator for a disaster scenario on Mars has to be faked! Well at least intentionally faked. It turns out Martian regolith/soil is also much more moist than expected so getting water will be relatively easy, but at the time of the book this wasn't known!

generalizations 3y ago
To be fair, it wasn't even the only disaster scenario in the movie - but it's very difficult to come up with a realistic scenario where someone would get left behind with a livable hab.
- jenadine 3y ago
  How about a fight between members of the crew causing the mission to be cancelled, and one of the member left for dead after a violent interaction with another member who then lie about it.
omoikane 3y ago
> The Martian The thin atmosphere bit is acknowledged by the author, you can watch his talk here around 32:35: I just want to be as accurate as I possibly could. There are a few places that are inaccurate. The biggest place that's inaccurate is right at the beginning. Don't tell anybody, but if you're in a dust storm on Mars, you're not even going to feel it. Mars' atmosphere is less than 1% of Earth's. So a 150 kilometer an hour wind would feel like about 1 kilometer an hour wind does on Earth. It wouldn't do any damage to anything. https://youtu.be/gMfuLtjgzA8?si=8aZUEizDWuBhnaJg&t=1958 https://youtu.be/gMfuLtjgzA8?si=8aZUEizDWuBhnaJg&t=1958 There is another clarification later at 35:34 saying the dust storm is basically like talcum powder.
- rob74 3y ago
  Well yeah, he needed some sort of catastrophic event to set the rest of the story in motion, and a huge dust storm which forces an evacuation and then separates Mark Watney from the rest of the crew was just the thing, so he added it although he was fully aware that storms don't work that way on Mars...
- danielvf 3y ago
  I don't know anything about mars, but I've messed with windmill math. This really doesn't make sense to me. A 150 mph wind in 1% atmosphere should be a way stronger a 1 mph wind on earth? You know the old formula, force = mass * velocity * velocity But with wind and water the more velocity, the more mass you get hit with in the same amount of time, so we get to multiply by velocity again. wind force = mass * velocity * velocity * velocity (This formula is why people die in fast moving water.) So a Mars 150mph wind (0.01 * 150 * 150 * 150) would have 34,000 times more force than a 1mph wind on earth. Which works out to around a 32 mph earth wind.
  - deleted 3y ago
    [deleted]
  - MathMonkeyMan 3y ago
    mass * velocity * velocity has units of energy. It's twice the kinetic energy.
throwbadubadu 3y ago
> which is otherwise a hard sci-fi book Hard sci-fi is still a story and doesn't need to nail everything. And it had other pretty "unrealistic" moments that put me more off than the storm. Foremost, how they fixed the missed orbital rendezvous, no never going to happen that way. Or that they could just revert their home flight and go once more back and back again, how much delta-v would that be, never could have had that much extra fuel at least in that world... and other minor things, but still superb story.
- NotSammyHagar 3y ago
  I thought in the martian they just looped the earth to go back, and then there was the supply rocket problem. They didn't do anything silly like just use the rocket to turn around and go straight back iirc.
jo38j8o3jo8rj3 3y ago
I remember some nasa administrator laughing about that at a conference. "So at the end of the movie the atmosphere is so thin that he can fly through it at thousands of miles per hour without harm, but at the beginning a sandstorm at hundreds of miles per hour destroys the ship? Also the spacesuits ... no."