A formal notification that condition "Argh!" exists

[james_davis_nicoll]

You cannot surround a star with a solid dyson shell and have people living on the inner surface/ Objects on the inner surface will have no gravitational attraction to the shell (all the forces from the outer shell cancel out) but they will have some measurable attraction to the star at the middle. This leads to a situtation technically known as "bad" as all the loose objects on the inner surface fall into the star.

Thank you.

Comments

[nexstarman.livejournal.com]

You can live on the outer surface, heated from the inside...

But building the polar regions of the sphere is the most daunting problem because you can't get them going at orbital speed like the equatorial area.

Thank you! You'd be surprised at the number of scifi franchises that don't realize this simple fact.

[razorsmile.livejournal.com]

I don't know jack about physics (beyond my failing grade in high school and a fuckton of comics) and even I knew that.

[lederhosen.livejournal.com]

Also, has anybody worked the numbers for the sorts of particles habitually emitted by a star, and made sure that catching them all in a shell wouldn't, say, cause a hydrogen buildup in the atmosphere? Maybe there's no problem there, but I'd feel happier if I knew somebody had checked it.

(Technically, you could have people on the inner surface as long as you spin the shell, but then the poles are uninhabitable, so why not just build a ring?)

[redaxe.livejournal.com]

(seen via friendsfriends)

I'd always inferred (if not stated in the various works of fiction I've read that used Dyson spheres) that a culture that could (and needed to) build a DS would have artificial gravity or some equivalent that permitted them to live inside. Or that they had a double-layer shell, with the inner surface being completely photo-converters to capture the star's energy, and living space between the shells. In either event, they'd also have to have attitude jets of some sort, but again, a culture at that level of technology ought to be able to handle the problem pretty straightforwardly.

[badgerbag.livejournal.com]

Hellooooo! They'd totally be wearing magnet boots. And loose objects are so "outie".

[redbird]

Note that "loose objects" in this context includes the atmosphere.

[blackbirdcd.livejournal.com]

And wouldn't the inhabitants be forced to wear SPF 50,000,000 sunscreen?

I'd hate not having a night-time.

[(Anonymous)]

1) Gravity generators! So easy!

2) Spin the sphere. Yes, this only works around the equator. Yes, the rest of the sphere is totally wasted. Presumably you don't care.

3) Live on the outside. You probably want a smaller star for this, since the gravitational force of the Sun at Earth orbit is around 0.002 gravities.

[pulls chin thoughtfully] Okay, this really doesn't work for anything but a red dwarf. Assume a star with 0.2 solar masses. It'll have about 1/400 solar luminosity, so you'd build the Dyson sphere about 20 times closer. This would give you a roughly lunar surface gravity, around 0.16.

Of course, you'll need artificial lighting... little fusion plants in solar orbit, I suppose. Don't dig any deep wells.

Anyway.


Doug M.