5 ms·

Objects in orbit are also moving pretty fast. Slowing it down a bit so that it's captured by Earth's orbit wouldn't take that much energy. Also, mass drivers wo

Objects in orbit are also moving pretty fast. Slowing it down a bit so that it's captured by Earth's orbit wouldn't take that much energy. Also, mass drivers would be the preferred option, no nukes necessary. A 200 metre asteroid might make a pretty big hole, but then so would profitable quantities of ore coming back, or a rocket capable of getting to the moon in the first place. Nobody seems to be too worried about SpaceX accidentally crashing their moon-capable rockets into a city.

JshWright 16y ago
Seriously? You're comparing a rocket with a self-destruct button to an uncontrolled projectile with several hundred times more mass?
- anthonyb 16y ago
  Several hundred? I think you're at least a couple of orders of magnitude out there... The point behind the rocket analogy was that rockets are inherently dangerous, uncontrolled projectiles. They explode, spin out of control, travel at hundreds or thousands of km/hr - but that's apparently ok. And it is, because there are safeguards in place. a) how are you getting the ore back to earth? Your choice is to either burn it back in on a rocket or splash down your hundred or thousand tons of platinum somewhere. Rockets are hideously expensive, which leaves you with... an uncontrolled projectile. b) mass drivers have a small amount of thrust, over a long period of time. It might take a couple of years to get it captured by earth - think slow orbit corrections over time rather than an uncontrolled asteroid missile. Once you get to that point, you'll have several more years to circularise the orbit. Hardly an uncontrolled projectile - Its path is easy to predict, and is incredibly unlikely to hit the earth. You'd need to burn a lot of energy to do so once it's in a stable orbit.
  - JshWright 16y ago
    Yep... you're right... s/several hundred/thousands/ My main point is that rockets have a big red button, and an 8,000,000,000kg rock does not.
    - anthonyb 16y ago
      Well, yes - but asteroids have plenty of time to correct, whereas a rocket doesn't. The safety measures are likely to be completely different.

JshWright 16y ago

Seriously? You're comparing a rocket with a self-destruct button to an uncontrolled projectile with several hundred times more mass?

anthonyb 16y ago
Several hundred? I think you're at least a couple of orders of magnitude out there... The point behind the rocket analogy was that rockets are inherently dangerous, uncontrolled projectiles. They explode, spin out of control, travel at hundreds or thousands of km/hr - but that's apparently ok. And it is, because there are safeguards in place. a) how are you getting the ore back to earth? Your choice is to either burn it back in on a rocket or splash down your hundred or thousand tons of platinum somewhere. Rockets are hideously expensive, which leaves you with... an uncontrolled projectile. b) mass drivers have a small amount of thrust, over a long period of time. It might take a couple of years to get it captured by earth - think slow orbit corrections over time rather than an uncontrolled asteroid missile. Once you get to that point, you'll have several more years to circularise the orbit. Hardly an uncontrolled projectile - Its path is easy to predict, and is incredibly unlikely to hit the earth. You'd need to burn a lot of energy to do so once it's in a stable orbit.
- JshWright 16y ago
  Yep... you're right... s/several hundred/thousands/ My main point is that rockets have a big red button, and an 8,000,000,000kg rock does not.
  - anthonyb 16y ago
    Well, yes - but asteroids have plenty of time to correct, whereas a rocket doesn't. The safety measures are likely to be completely different.