--- In spacesettlers@yahoogroups.com, "William" wrote:
> --- In spacesettlers@yahoogroups.com, "hitssquad" wrote:
> > --- In spacesettlers@yahoogroups.com, "William" wrote:
> >> --- In spacesettlers@yahoogroups.com, "hitssquad" wrote:
> "They can only build so many floors before the whole thing
> collapses. We can build buildings now perhaps 3000 stories?"
> (Repeat of earlier post.)
> Long before the structure you describe gets built it will have
> collapsed under its own weight. It's estimated that even buildings
> made out of pure diamond can only go up about 600 km., and even
> that's not taking into account earthquakes and continental drift.

I don't know what advanced materials might be available to a future super-technologically-powerful society of a quintillion people, but I do know it would be absurd to build the top out of the same material as the base.

> > A triple-radius Earth could give each of a quintillion people
> > an average of a million cubic feet of space.
> Which would require importing many times the amount of nitrogen as
> there is on Earth

Yes. And?

> Your original point was "there's far more resources on Earth than the
> rest of the Solar System". Q.E.D.: Not So.

That's not an accurate quote of me. Do you mean this?: "There are (non-hydrogen) resources near Jupiter, but they're badly outclassed by the
resources of Earth."

Is that wrong? My original point was that a Swiss family Robinson, or a small community of such, presently have no *resource-based* reasons to leave Earth for other parts of what is commonly considered the solar system:
http://en.wikipedia.org/wiki/Pale_Blue_Dot

"The Voyager 1 spacecraft, which had completed its primary mission and was leaving the Solar System [...] Astronomical Units 40.47"

That's barely beyond Pluto. Here's what Victor Smith had written:

"
hundreds of families or small businesses will build mining ships with off the shelf tech and set out to an asteroid to claim, homestead and mine to make their fortunes, driving man farther and farter into the outer solar system, growing their families and splitting off as more asteroids, comets and moons are colonized. Given all these factors, I cannot see it taking more than five centuries tops before we've SETTLED most of the system in large numbers
"

"Most of the system" might encompass Mercury to Jupiter. I asked what Swiss family Robinson -- or a small community of such -- might hope to find out there:

"Why would the solar system be settled at all, while there are vastly more
resources on Earth?"

Most people are not looking for more nitrogen. I don't think, over the next 500 years, anyone is going to be looking for nitrogen. The first non-Earth place I would look for nitrogen, though, might be Venus. Mining Venus for nitrogen hardly qualifies as "[settling] most of the system in large numbers".

In a nutshell: the failed Limits To Growth theory -- upon which much space advocacy of the past 4 decades has been erroneously based -- won't be a reason for any Swiss families Robinson to leave Earth within the next "five centuries". The total resources on Earth have been exploding in quantity and quality for the past two centuries, and they continue to explode.

> > There are advantages to being at the center of the action, rather than out in the hinterlands.
> I have not talked about the quality of life [...] With great restraint.

Maybe you required restraint because you haven't read this:
http://www.juliansimon.com/writings/Ultimate_Resource

When one is at the center of the market action, one can more easily buy -- or create -- quality of life. People like parks and zoos. It's not necessarily impossible to put parks and zoos of indefinite size and quality inside multi-story buildings.

> >> Long before you get to quintillions of humans, you will bump into thermodynamic limits of how many humans can exist on the Earth at once.

It's interesting you would mention that, given that brooksn just proposed that a population level of a quintillion humans would cause the poles to freeze:

"You'd have to create a mechanism to keep the [...] polar and northern latitudes from getting too cold."

> > It would require cooling measures -- perhaps including laser cooling via solar-powered lasers at Sun-Earth L1, which might also block all sunlight from hitting Earth
> Which would involve further use of resources from elsewhere in the solar system -- energy.

Again, placing a sunshade at Sun-Earth L1 hardly qualifies as "[settling] most of the system in large numbers".

If generating power *while* shading the earth from the sun offends you, then the necessary power could simply be generated with fission of heavy-metal fuel sent from Earth.

You're not seriously proposing that Earth-based civilization needs more energy resources, are you? There are 40 trillion tonnes -- 32.4 billion years' worth at the present burn global society all-fuels burn-rate of 16 terawatts -- of fission fuel (40 tt uranium + 160 tt thorium) in the earth's crust alone.

hitsqad wrote:

In a nutshell: the failed Limits To Growth theory -- upon which much space
advocacy of the past 4 decades has been erroneously based -- won't be a
reason for any Swiss families Robinson to leave Earth within the next "five
centuries". The total resources on Earth have been exploding in quantity
and quality for the past two centuries, and they continue to explode.

I am sure your statement will come as a shot in the arm for a recession hit
world :-) What we hear is talk of limits to growth, such issues as EROEI
(Energy returned on energy invested) and global warming. And we are still
to have any meaningful presence in space.
I think we need to get this conversation back to something real like
getting the first 1000 people out into space.

Regards,
Selvaraj

On 18 March 2012 01:39, hitssquad wrote: