Cheap TSW/Ringworld takeoff

[Corvus 501]

This is a blatent takeoff from The Salvation War, and Larry Niven's Ringwod searies.
1. A Supernova happens, and inertal dampener field appears, stblantiant ops the matter from leaving.
2. Matter gets transmuted, a shell of collapsed matter is made, which holds the rocky and metallic shell of the Dyson Sphere.
3. Multiple super Jovian gas giant planets are used to fill about 30% of the Sphere with an oxy- nitrogen atmosphere. The other 70% is walled off, and open to space.
4. The sphere is orbiting at one AU from a yellow dwarf star, (another gas giant, a brown dwarf star, with added mass to make it a star) at less than one gravity (9.80665 metres per second squared) because of the mass of the Dyson Sphere itself.
5. It has oceans, rivers mountains, forests, deserts, plains, and many more features, and it was terraformed long ago by the race that built it, and seeded with life just like the many other habitats that they made.
6. Inside the main ring, there is a second ring, who's orbit is designed to cause the internal sphere nighttime.
7. The outer sphere was seeded with intelligent life, as was the ring. The inhabitants can travel between the two only with great difficulty, mostly because of rotational differences
8. A colony from the ring took over most of the sphere, and settles there, and over the years, became a different species, physically, at least.
9. As a result of the inhabitants visiting Earth, and inspiring legends, this place became thought of a Heaven and Hell.
10. They got to Earth by using wormhole portals to travel here. This stops, after a while, mostly because humans start sending armies after them, and (sometimes) wining, but mostly just resisting, something that the inhabitants of the Ring and the Sphere where unused to.

[Simon_Jester]

Yes... and?

[Corvus 501]

That's as far as I have gotten to writing so far.

[Simon_Jester]

Yes, but what are we supposed to DO with it?

You forgot to ask us any questions.

[Darth Tanner]

Random maths...

Even with a magic induced supernova that turned 100% of the mass of our star into iron your only going to have a 7m thick shell at that distance. Relying on that for your gravity is going to be an issue. Of course you wouldn't then have a dwarf star left at your centre so you can't rely on using that large a % of your starting star.

Also to fill 30% of that surface area with an atmosphere (presuming just a Troposphere) with gas assuming Jupiter is 100% suitable to be pumped in you would need 81,000 Jupiter's. If you want a Thermosphere as well your going to need multiple millions of Jupiter's.

[Simon_Jester]

Just go with a ringworld, a Dyson shell of solid matter completely enclosing a star is stupidly excessive. In this case it's supposedly made out of iron, in a shell too thin to have noticeable self-gravity and WAY too weak to be spun for gravity.

Having the ringworld explicitly be a microgravity environment with an enclosed ceiling to keep the air in might actually be a fun choice; it's just impossibly hard to spin a megastructure for gravity and stay vaguely within the bounds of hardish-SF material science. Sure, Niven did it... but Niven posited that the ringworld floor was made out of "scrith," a material with tensile strength comparable to that of an atomic nucleus. O_o

[Terralthra]

The interior of a uniform hollow sphere has zero self-gravity regardless of material, thickness, or any other attribute. Trivially proven using Gauss's law for gravity, or an integral across the sphere's volume if you're feeling super fancy.

[Simon_Jester]

This is true. The only ways to beat it that I know of are:

-Construct a heavy pancake of matter directly under your habitat, built into the surface of your hollow sphere and adding an extra mass right 'below' your feet. Its gravity pulls you downward. I'm pretty sure you can get away with doing this on a solid belt clear around the sphere, with each point experiencing at least slight gravitation toward the surface. I'd have to break out my multivariable calculus to be sure and it's too late at night, though, so I might be wrong.

-Spin the structure for gravity, which works great for things a few miles across and very badly for things the size of a planetary orbit.

-Live on the OUTSIDE of the sphere, in which case you get no sunlight and can't spin for gravity, but do get at least weak gravitation toward the star (and the floor between you and the star).

[Beowulf]

You could do the Buuthandi route: you're hanging from the dyson sphere on the inside of the sphere, with the sphere being inflated by the solar wind/light pressure. The sphere doesn't orbit, so it doesn't need to have any real strength. Still have fairly weak acceleration towards the star though, so it's probably not that great for actually living in. Also, you're in a hab, not a large open area, which makes travel from hab to hab difficult.

[Terralthra]

-Construct a heavy pancake of matter directly under your habitat, built into the surface of your hollow sphere and adding an extra mass right 'below' your feet. Its gravity pulls you downward. I'm pretty sure you can get away with doing this on a solid belt clear around the sphere, with each point experiencing at least slight gravitation toward the surface. I'd have to break out my multivariable calculus to be sure and it's too late at night, though, so I might be wrong.

Pretty sure a ring suffers the same outcome as a sphere: the strong pull directly under you is exactly balanced by the more diffuse pull from the rest of the ring.

[Simon_Jester]

Pretty sure a ring suffers the same outcome as a sphere: the strong pull directly under you is exactly balanced by the more diffuse pull from the rest of the ring.

You could be right but I'm not sure it's that simple. Hopefully some time today I'll have time to sit down and integrate.

You could do the Buuthandi route: you're hanging from the dyson sphere on the inside of the sphere, with the sphere being inflated by the solar wind/light pressure.

The thing about a "buuthandi" is that there's no obvious advantage to building one, unless of course the buuthandi fabric is actually a sort of thin-film solar panel that just happens to be light enough to be supported by radiation pressure. Which is kinda questionable, in my opinion.

Unless you have that, you might as well just put the habitats directly in orbit around the star.