Planet Bob

[Walrus]

Ok, so I was getting itchy since our group can't really meet till Sabine is a bit less demanding, so I started to work on the idea of my own world. I find myself with truely 'huge tracts of land' to fill
An equatorial circumfrence of 460,557,483 km, leaving a huge surface area that can be used.

Worldbuilding! Planet Bob!
I've had some devious ideas and am finally building a world. Extra input in the form of ideas about npc's, geography, societies, towns, cities, etc etc.

https://kawarthakrewstories.wordpress.c ... rticipate/

[Walrus]

I submitted the idea to a guy on a Google + group, and he rendered an image of Bob - and is using the idea in his own setting, so came up with some story around it will lnk here...
He called it Gruppa for his setting
https://plus.google.com/+AndrewChason/posts/4vWiip98XrY
Based on my idea

https://docs.google.com/document/d/1srm ... sp=sharing

The Star Wars setting I was thinking, was that the Dyson Sphere was made by the Kwa Species during and after the war with the Rakata and their Infinite Empire.
http://starwars.wikia.com/wiki/Kwa
http://starwars.wikia.com/wiki/Infinite_Empire

I intend to place this system on the 'west' side of the core, just beyond the deep core in my setting.

[Walrus]

As for the outside, I figure an AD&D setting world - of EPIC proportions. i was going to start my construction with the Council of Wyrms setting, but the map is going to have to be expanded to fit my planet.

Space-ships cannot make a 2 way trip to the surface from the outside.
And the Kwa on the inside don't tolerate the idea of using the construction's passageways to get to it.
The automated magenetosphere defense of the Dyson Sphere destroys electronics that make too close, causing ships to crash, leaving their survivors sans technology, if they survive.

The magic may be an extension or manifestation of the living force.

[Mike]

I'm curious about the distribution of lands and seas on the surface. You have the room for massive interconnected collections of continents separated by unimaginable stretches of ocean. Like Ringworld, travel across these oceans would be the analogue of space travel. Imagine multi-generational ark-ships (or ark-fleets of smaller ships) that follow the world currents for 400 years to reach distant lands.

[Walrus]

[Walrus]

actualy my first challenge i mathematical.I was thinking, The north south, when you go say 40o from the equator the polar region where the chances of survival without more modern cold protection is impossible. (magical protection not withstanding.)

I just need to do the math on how far that is around the globe.

[Mike]

40 degrees is about 65 million miles?

Imagine a ship that can travel non-stop at 100 miles per hour indefinitely. That ship takes 14 months to travel 1 million miles. That's almost 7 centuries to circumnavigate the globe.

Also, you can have changes in elevation that are unheard of on earth. Easily, you can have geographic features that rise above the atmosphere. But what about depths? Imagine a basin situated such that there are two or three atmospheres of pressure on top of the region. What does that do to physics?

You can also make the equator too hot or whatever for unmodified humans. The poles too cold. Almost like having some of the elemental planes located on the same globe as the prime material.

[Walrus]

Ok So avoiding the need or desire for calculus

circumference 942477796.07 km divided by 360 giving me 2,617,993.88 km per degree
104,719,755 to the freeze to death in minutes region from the equator

So doing the math, the approx sq cm of surface area of liveable space is in the quadrillions of square km ..... Koooooieee

if we approximate, (super rough) a year for a sailing trip around earth, then scaling that out - assuming the same speed average ....
23,518 years for a single circum-navigation of the 'planet'

with your average dragon making an average of 116 km a day
https://rpg.stackexchange.com/questions ... dragon-fly
8,124,808 earth standard days for a dragon to fly around 'Bob'

Hot DAYMN!!! I've created a monster!!

[Walrus]

I had thought, depths of beyond 2 km would strike the surface of the dyson sphere proper....
yes, some mountains I had thought of as breaching the atmosphere.
Above 40o latitude either north or south is going to be beyond human tolerance cold. Hadn't thought of a too hot for human tolerance band ... but that is a cool idea, separate the bands .... I likey....

[Mike]

FUN!

You want Bob to have 1 standard earth gravity at the surface just based on mass and normal physics? Then the entire structure has as much mass as 1600 of our suns. That value is true whether the structure is solid or whether it is a giant hollow shell.

[Mike]

You can also introduce a variety of super extreme weather effects, if it would suit the setting.

[Walrus]

[Mike]

Gravity on earth varies only in tiny amounts (like less than half a percent, with virtually all of the variation due to difference in elevation relative to the center of the earth.)

As for the Dyson sphere, as long as it has the mass of 1600 suns, the acceleration due to gravity at 150 million km from the center will always be 9.8 meters per second per second. If you create a thin hollow Dyson sphere that is roughly uniform, you get 9.8 m/s2. If it's a giant incredibly lightweight styrofoam ball of the same size... 9.8 m/s2. If it's a black hole with the mass of 1600 suns, the acceleration at the 150 mil km mark would still be 9.8 m/s2. As long as the distribution of matter is balanced around the sphere, the gravity doesn't change. It's cool like that.

And at that size, you'd need variations in altitude of over 650,000 km to see variations in gravity the size of those on earth.

All of which is to say that I am a huge planetary physics nerd, and while this is fun for me, you can take or leave as much of it as you want. Because you are building something that is essentially a fantasy world, and your story needs trump any "Um actually..." I might have.

[Walrus]

Hey, I'm all for putting a bit of real physics behind it where appropriate.

The thing that puzzles me - not all the mass of the dyson sphere is nearly close enough to provide gravitational pull, and the shell of the dyson sphere would provide a bit more gravity to the inside surface than the star would pull folks away from it.

It's just that the mass of the shell beyond a certain distance from the point in question wouldn't have much effect, surely that would reduce the total gravitatonal pull in any single point.

Maybe I have the complete wrong end of it.

Still, I'm planning to have a lot of fun with the day length thing, two gas giants turned into red dwarves that orbit at different speeds. sun-rises that are actually rising suns not spinning globes....

[Mike]

All mass provides gravity, regardless of distance. On the Dyson sphere, the part of the shell directly under your feet provides more pull than the stuff farther away, but it balances, and the total mass of the entire shell provides the same effective gravitational pull as if the entire mass of it were concentrated into a point mass at the center of the whole mess.

This is taken from an XKCD What If episode on falling through the center of the earth (I think... if I remember correctly).

[Walrus]

Really? huh, I wouldn't have expected that ....

Well - some tech-babble can explain that, and give me some really cool options when the tech fails

Real physics is great, but I want it to support the story not break it

Say, what do you think of my 40 degrees either side of the equator to get to space-cold levels toward the poles? seem realistic enough?

[Mike]

I'm cool with that. Seems reasonable.

However...

Where does light and heat come from on the surface? If heat comes up from underneath (presumably there's still a working star at the center of Bob, and excess heat must be vented somewhere), then you can create hot spots or thermal phenomena in whatever pattern makes you happy.

Hell, what if you say excess internal heat is vented st both poles, making them both uninhabitable, but air and ocean currents carry that heat away, and you wind up with everything above 60 degrees from the equator too hot for humans. Everything within 30 degrees of the equator is a mostly uninhabitable frozen band. The temperate zone between 30 and 60 is where most life is. Basically reverse the earth.

Or vent at the equator and keep something like you're thinking of. Or make some other pattern that you think is cool, like hotspots all around Bob creating hundreds of vast inhabited regions, all separated by hundreds of thousands of miles of frozen waste. Or spread it out evenly so that the whole of Bob is inhabitable.

Or you could leave out internal heat entirely. Whatever.

As for light on the surface, I assume you'll have some kind of day-night structure. Possibilities:

No external light sources. This seems gloomy and difficult.

Maybe you have one big, distant, Betelgeuse sized star orbiting Bob too far away to provide much heat, but it gives us some sort of day/night.

A couple dozen stars in a carefully balanced, interwoven set of orbits that provide all portions of the globe with complex patterns of light, dark, and twilight.

Maybe there's actually a roof on the whole thing. Imagine Bob as you've already laid it out. Now put a second shell around it at about 100 km up. You can have heat and light produced from fake "suns" in the firmament of the sky. And these can move and vary to create whatever kind of days and seasons you want. It would also let you have these massive "world pillars" that seem to hold up the sky and carry power and heat from the core to the outer shell.

So much you can do.

[Mike]

Can't stop the math!

Take the idea of hotspots around the world with vast tracts of frozen wasteland between them. Combine that with the roof over the world and put a World Pillar at the center of each hotspot. If you put up 360,000 of these spread evenly around the globe, each one would command an area about equal to a circle 1 million km in diameter. 360,000 individual realms, each one with an area equal to 1500 earths. Glorious.

If I were stealing this for my own, I'd do something like that. But the possibilities are endless. By tomorrow I'm sure I could have five more equally cool ideas.

[Walrus]

The thought I had, was that the Dyson sphere was created in a Sol like system, the remains of the inner orbits have been mind into oblivion, they would be inside the sphere, or would have been.
Later orbits included two gas giants (much like satern and jupiter) that were either deliberately or incidentally ignited into red-dwarves, their orbits providing a rather strange binary sun system for the 'planet' on the external surface.