Without a bulge, the top would be half GEO (was Triple the radius)

--- In spacesettlers@yahoogroups.com, "Victor Smith" wrote:
> hitsquad said:
> > (The new "surface" of Earth would be around the present 8,000-mile altitude. According to present standards, that would put most of the habitation area into "deep space", though still only 1/3rd of GEO at the most.)
> are you going to pressurize this huge "building"?

Air is what the nitrogen is for. I imagine that all living and working condominium areas would be pressurized by the interested parties. Some storage condominium areas might be unpressurized for storage of those articles that store better in a vacuum.

If you have any nitrogen for sale, I'm sure you'll find a ready market.

> by building out 8000 miles from the surface, you are, in essence, lowering the density of the planet.

Yes.

> So, doesn't that mean that the "core" [...] will attract things (air, people, etc...) LESS?

Yes.

> And, if you move a lot of the mass of the planet 8,000 miles out from what used to be the surface, isn't that going to make all that mass increasingly subject to centrifugal force, and subject less and less to gravitational attraction from the core?

Yes. GEO is much higher, though. Doubling the distance from the center of gravity drops gravity to 1/4th. Tripling the distance from the center of gravity drops gravity to 1/9th. People near the top wouldn't feel much gravity, especially near the equator. I assume that area would have vacation resorts, just as it does today. People who want to get serious work done don't tend to live in the tropics.

Naturally, there would be a bulge at the equator, just as there is on every planet that spins fast enough. (Venus spins very slowly (only once every 243 Earth days), and so doesn't have much of an equatorial bulge).

> As these are all rather stupendous forces, it seems to me that combined with coriollis effect, the structures couldn't last.

That logic only applies if the forces are oscillating -- which these are not. There would still be the oscillating tidal forces of the moon and -- to a lesser extent -- the sun, just as there are today. Those would have to be considered. Just like those would tear apart a large O'Neill cylinder orbiting too close to Earth, they might tear apart any other large structure.

> are we all going to fly at the higher elevations, 'cause we ought to be weightless.

No, because even at the highest elevations, you won't be at GEO. (That's why I would consider the highest elevations vacation-land, or convalescent land.) That's an interesting thought though: building beyond GEO to get reverse gravity from the spin -- just like in an O'Neill cylinder.

The low weight and hard vacuum at the highest elevations might make spaceship docking and launching pretty easy, though. Spaceships might be launched and landed with electric catapult systems like those slated for the next class of US aircraft carriers. At the highest equatorial elevation from center of 18,897.6 km, not considering any bulge, rotational speed would be 52.8% (1.621 km/s) of GEO's 3.07 km/s, since that elevation from center is 52.8% of GEO's 35,785.37 km.

That elevation currently has an orbital speed of 4.59350 km/s. That would require almost 3 km/s of acceleration/deceleration of space vehicles by the electric catapults. That might not be doable, but then perhaps an extra-high-elevation launch/capture platform could be installed.