Thoughts about sphere worlds

[Kamog]

It seems that there is only one picture for a sphere world, and it's a dark grey color regardless of the atmosphere type. I thought that it would be nice to have a blue sphere world for an oxygen atmosphere, red for hydrogen, and so on, just like the planets.

But I guess that the atmosphere is on the interior of the sphere and not on the outside, so the inside surface will have different colors, whereas the outside has no atmosphere and has the same appearance as a "none" planet..

So the facilities and population live on the inside surface of the sphere world, and they get sunlight from the star in the center, right? Now, I'm assuming that the sphere rotates around to create artificial gravity so that everyone stays on the ground and doesn't fall down into the star in the middle. But with a rotating sphere, the artificial gravity will be strongest at the equator and get weaker as you go towards the poles, and at the poles there won't be any gravity. So if you live on the equator, and experience 1G of gravity, you start walking north. As you progress north, you will get lighter and lighter, and then become weightless, and then the direction of the gravity will reverse, so that you fall towards the star.

Does this make sense, or am I missing something?

[se5a]

if the sphear world has enough mass you wont need to spin it as it will have its own gravity.

how well that would work on the inside of a sphear I dont know...

[Baron Grazic]

I always thought that was strange, that you build a Sphere World, and live on the inside. Why wouldn't you live on both sides? Admittandly the inside would be huge, but surely you would have your Space Yards, possibly explosive Weapons Research labs, etc on the outside?

[PvK]

Assuming a solid, opaque sphereworld, there won't be any sunlight on the outside. On the other hand, if you have the technology and resources to build a sphereworld (which, incidentally, practically no one would), then you can proabably find a way to get enough light and heat on the dark side.

I don't know why you'd assume there wouldn't be things on the outside, anyway.

As for the original question, a ringworld could turn to give the desired amount of centripetal force to be equivalent to gravity, although that would be part of the already absurdly enormous engineering problem.

The sphereworld ... egad. If you have the technology and resources to actually do such a thing, then I expect you probably just use whatever magic gravity-making tech you probably mastered a few thousand years earlier, to make it work. But, generally speaking, yes, if you spin to 1G at the equator, the centripetal effect would get less and less as you moved away from the equator towards the poles, where there would be no centripetal force, and yes things approaching the poles that weren't held some other way would fall towards the sun.

I haven't done the math for over ten years now, but I hypothesize that the mass of the sphere itself can't be used to compensate unless it is very uneven, because an even sphere of any mass would still have it's center of gravity in the center, where the sun is. Perhaps by using a ridiculous amount of mass increasing at the poles, actual gravity could take over at the same rate that centripetal force tapers off, resulting in an even 1G everywhere on the inside of the sphere.

Again, though, there are so many other problems of ridiculous scale in the proposed project, that if you can solve all of those, I expect you've got plenty of solutions for keeping objects from falling inwards... and probable, even more good ideas for other things to do besides build a sphere world.

Besides, your plants and animals will get really confused by having it always be 12:00 Noon according to the sun. I sure wouldn't want to live there.

PvK

[ November 24, 2003, 05:15: Message edited by: PvK ]

[Taz-in-Space]

Hmmm, never thought about what gravity would be like inside a Sphere World. My totally non-scientific guess would be that the local gravity of the Sphere-world structure would hold you against the pull from the sun. BUT I cannot see that that pull would be great enough to equal earth's gravity and so any atmosphere should be very thin.
Of Course, anyone advanced enough to build such a thing, might have some way to augment the local gravity.
MY QUESTION is where would the Solar Wind go?

[ November 24, 2003, 05:05: Message edited by: Taz-in-Space ]

[PvK]

Originally posted by Taz-in-Space:
...
MY QUESTION is where would the Solar Wind go?

Directly onto the bald spot on the top of your head, as long as you were standing up.

PvK