5 ms·

It's shame that after that entire explanation (the moon-earth firepole one) that he never actually answers the question of how long it would take...

saagarjha 5y ago
Most of the time goes into climbing, which he estimates as taking "several years".
- LorenPechtel 5y ago
  You can't climb the pole. Tsiolkovsky's rocket equation rules, you can't bring enough food to climb the pole. (Yes, I know, it's not a rocket. It really should be called Tsiolkovsky's logistics equation--it applies to any situation where you have to bring along your power source, whether it's a rocket or not.)
  - Sohcahtoa82 5y ago
    Really? I must be misunderstanding something then. The Earth-Moon L1 point is ~63 km from the Moon. Let's say me and my gear weigh 200 lbs, and the Moon's gravity acceleration is 1.62 m/s^2. 63 km * 200 lbs * 1.62 m/s^2 gives a potential energy of only 2,213 kcal. The human body is only 18-26% efficient [0] at converting food into energy, so we're probably looking at around 10-13,000 calories. Depending on what you're eating, that's 4-10 lbs of food. Obviously, I'm ignoring the time it would take to climb that far, but in terms of energy, it seems reasonable that a human could carry enough good with them, unless I'm gravely misunderstanding something. I'm guess that assuming "potential energy" means "the energy needed to move X pounds to Y height at Z gravity" is incorrect. [0] https://physics.stackexchange.com/questions/46788/how-efficient-is-the-human-body https://physics.stackexchange.com/questions/46788/how-effici...
    - saagarjha 5y ago
      I believe your L1 distance is off by about three orders of magnitude.
      - Sohcahtoa82 5y ago
        Oh crap you're right, not sure how I got such a low number.
  - saagarjha 5y ago
    The rocket equation is not necessarily relevant here, because you can have the pole be a space elevator that brings you food.

saagarjha 5y ago

Most of the time goes into climbing, which he estimates as taking "several years".

LorenPechtel 5y ago
You can't climb the pole. Tsiolkovsky's rocket equation rules, you can't bring enough food to climb the pole. (Yes, I know, it's not a rocket. It really should be called Tsiolkovsky's logistics equation--it applies to any situation where you have to bring along your power source, whether it's a rocket or not.)
- Sohcahtoa82 5y ago
  Really? I must be misunderstanding something then. The Earth-Moon L1 point is ~63 km from the Moon. Let's say me and my gear weigh 200 lbs, and the Moon's gravity acceleration is 1.62 m/s^2. 63 km * 200 lbs * 1.62 m/s^2 gives a potential energy of only 2,213 kcal. The human body is only 18-26% efficient [0] at converting food into energy, so we're probably looking at around 10-13,000 calories. Depending on what you're eating, that's 4-10 lbs of food. Obviously, I'm ignoring the time it would take to climb that far, but in terms of energy, it seems reasonable that a human could carry enough good with them, unless I'm gravely misunderstanding something. I'm guess that assuming "potential energy" means "the energy needed to move X pounds to Y height at Z gravity" is incorrect. [0] https://physics.stackexchange.com/questions/46788/how-efficient-is-the-human-body https://physics.stackexchange.com/questions/46788/how-effici...
  - saagarjha 5y ago
    I believe your L1 distance is off by about three orders of magnitude.
    - Sohcahtoa82 5y ago
      Oh crap you're right, not sure how I got such a low number.
- saagarjha 5y ago
  The rocket equation is not necessarily relevant here, because you can have the pole be a space elevator that brings you food.