Quintillions on Earth, wished away (was What off-Earth resources?)

--- In spacesettlers@yahoogroups.com, Joe Strout wrote:
> On 3/9/12 1:05 AM, hitssquad wrote:
> > Where would these quintillions (you did say "vastly outnumber") of off-Earth people get their nitrogen -- from Titan and Triton?
> I'm not sure we have to go to quintillions -- even trillions would count as vastly outnumbering

...Only if there weren't a quintillion or more people on Earth, by then. Perhaps you'd like to propose that's not possible, and then explain why.

> > > The rest of the solar system is [...] full of resources
> > The mystery remains what those resources might be. There's hydrogen and helium in the gas giants, though that's unavailable until starlifting technology is developed (yes, I'm calling the gas giants stars -- small, cold stars).
> a crude method would be to simply launch payloads of liquified hydrogen [...] by rocket.

Problems: The 2.528 g "surface" gravity causing: gravity losses; hydrostatic pressure at the bottom of the cargo and fuel tanks; in the unlikely event of a fusion rocket being able to produce enough thrust to even just hover, the rocket to be crushed; if the rocket is large, the rocket to be torn apart by tidal forces.

The "atmosphere" causing drag losses.

The 59.5 km/s escape velocity. To reach it in a hurry, before gravity losses overcome, means possibly crushing the rocket. The total delta-v with gravity and drag losses included might add up to hundreds or thousands of km/s. Somehow the engines delivering this delta-v would have to be cooled, or they might melt. Sure, we could cool the engines with liquid hydrogen, but after all that thrusting and cooling effort, would much payload fraction remain?

> A better method would be to build a big linear accelerator, floating buoyantly, and launching hypervelocity cargo carriers.

The thick "atmosphere" makes that seem unlikely.

> Then there's energy -- the Sun puts out an awful lot of it

No, it puts out a lot of power -- and Jupiter receives very little of it. So, that doesn't answer the question of what anyone would want at Jupiter that one couldn't find on Earth.

> which is (to a good first approximation) currently streaming off into interstellar space, completely wasted.

Yes. We can consider it wasted because of the fact that we use more than zero of it. One way to stop wasting it would be to stop using any of it at all.