Walking around outside naked in deep space (was Triple the radius of Earth)

--- In spacesettlers@yahoogroups.com, "brooksn" wrote:
> --- In spacesettlers@yahoogroups.com, "hitssquad" wrote:
> > --- In spacesettlers@yahoogroups.com, "brooksn" wrote:
> > > I would have to agree that gravity will become an issue, with removing most of the mantle
> > What? Where'd you get the idea most of the mantle would be removed?
> You're building the Earth up 8,000 miles or 42 million feet into the air/medium Earth orbit, with pressurized honeycombed living space. That sounds like a lot of material and you mentioned taking it all from Earth. How much of the mantle would that take?

The earth masses 6e21 tonnes. If each of a quintillion people used an average of 28 tonnes of material (the same as was just reported here for a Bernal Sphere holding 140,000 people), it would total 28e18 tonnes, or less than one half of one percent of the mass of the earth.

To put that in perspective, the earth's lithosphere masses 1.365e20 tonnes. Therefore, all the necessary material could be drawn from the lithosphere, leaving another 4/5ths of the lithosphere behind.

The spinning-figure-skater analogy works as long as her limbs mass no more than 2 ounces each.

> > > reducing the magnetosphere and therefore reducing the Van Allen belts.
> > Charged particles can be repelled by artificially-generated magnetic fields.
> But like many other things the Earth provides this without relying on humans to screw it up when there's a problem. Another seperate issue is heat transfer, currently the Earth provides a nice mechanism of transfering heat via ocean currents and even hurricanes from the hotter equator to the colder north latitudes. (Which is why Europe is relatively nice and doesn't have siberian temperatures.)

> You'd have to create a mechanism to keep the equatorial regions from getting too hot

No, because there's no sunlight. As I said, it's all being intercepted at Sun-Earth L1. At least some of that intercepted sunlight is being used to power the cooling lasers aimed at the radiator towers on Earth. There would need to be some system of transporting heat to the cooling towers. I imagine it would be a lot like any other transportation network, except that its job would be the transportation of heat.

> and the polar and northern latitudes from getting too cold.

I imagine the heat generated by human action would be relatively evenly spread around the globe. I don't see any reason why it wouldn't be, and taxes and subsidies could always be applied to discourage and encourage heat production respectively in the exact places that respectively needed more or less heat. It's hard to imagine any place on an Earth with a quintillion people -- all generating heat -- actually needing *more* heat, though.

> Again mother Earth has been kind enough to provide.

Earth's natural-process "free" provisions are already dwarfed by the net resources created by today's relatively small population of 7 billion. We can reasonably expect they would be dwarfed even-more-so by the respectively far larger populations of a trillion, a quadrillion, and a quintillion. Humans are not net consumers, on average, but net producers. Therefore, more people = more resources per person.

> > > Many much larger, even a modest 1 foot meteor is going to cause lots of damage to the honeycomb areas that are struck, plus the loss of atmosphere, not to mention life.
> >
> > How many times has the ISS been struck by 1-foot meteors? Apply those odds to any part of the expanded Earth. A far future population of a quintillion might have figured out how to track 1cm+ sized meteors and give sufficient advance warnings of impact. Meteors might even be blasted by defensive lasers.
>
> How times has ISS had to course correct to avoid a collision?

...To avoid a meteor? Never, as far as I know. All the course corrections had to do with artificial satellites and space debris.

> About a 40 centimeter, almost half a meter, hits Earth every day, and a 4 meter hits Earth once a year. [...] if you increase are radius dramatically those numbers rise quite a bit as there are many near misses.

The new radius would be 3x the old, so the meteor strike frequency would be 9x. Even if no mitigation or warning systems were in place, any given individual of the quintillion would be at very little risk of a meteor hit, just as airplane passengers are at very little risk from meteor strikes today. People below a very thin layer at the top wouldn't be at any risk from meteor strikes. That thin top layer acts as a crumple zone.

The larger a meteor is, the more dangerous it is, but also the easier it is to detect. Therefore, the larger the meteor, the more likely it will be detected, and the more warning time there will be on average, giving opportunity to evacuate and/or mitigate. People who didn't like whatever the odds would be could protect themselves by living/working/recreating below the thin meteor-danger layer. However, given the ISS has never had to move for a meteor, I'm not sure that "safety" argument against living in the "danger" layer would make sense for anyone.

> But use a lava cave on the moon, a cave or narrow canyon on Mars or inflate a rubble pile asteroid and viola much of the protection from these issues are provided for.

What would stop a technologically powerful organization of a quintillion people (143 million times as many people as there are now, and therefore at least 143 million times as powerful) from detecting meteors and adjusting the meteor paths to avoid collision, or blasting the meteors with lasers?

> PS Had you seen the Uranus/Neptune numbers?

No. Thanks for posting them.