Non-Earth Dieselpunk settings

[The Kilted Yaksman]

There is also a table-top minuatures game called Battlefleet Gothic, that might fit your aesthetic criteria.

Spoiler (click to show/hide)

[chironex]

How, exactly?

[chironex]

Hard vacuum?
War Rocket?
Slipstream?

[Julian]

I like the ships used for war rockets. 

[chironex]

There was also (sort of) the Reich Stuff supplement for Tales from the Floating Vagabond RPG.

[Shadow Of The Tower]

Sun of Suns, the first books of the Virga series by Karl Schroeder I think fits your search.

It takes place inside a gigantic empty sphere, thousands of miles across, but filled with air and small artificial suns, ocean sized blobs of water and small muddy asteroids. The only gravity is produced artificially in  giant spinning cities made from wood and rope and the people fly around on alcohol powered airships.  Because there is air but no gravity the airships resemble unpressurized spaceships, built mostly from wood, powered by simple jet engines and armed with cannons.  Gravity and light are the most valuable resources and people fight for space on the rotating ring cities and guard their orbits around the artificial suns.

[Julian]

Sun of Suns sounds really cool.  I will take a look at it. 

[Shadow Of The Tower]

Well, I like the series. The idea of weightless, low tech society is really fascinating.  I really like the tiny asteroid worlds. Some of them are only a couple hundred feet across, have no gravity and are populated by a single family that lives in a cave inside and farms on the surface.

The warships are awesome as well. With no gravity there is no constraint to their size and the bigger the better but if your not careful you can get blow off and end up floating forever in thousands of miles of empty air.

One of the largest cities is tethered to an asteroid by a long rope and has sails that make it spin for gravity as it trails behind the asteroid.

This is a teaser drawing from the upcoming graphic novel.

Spoiler (click to show/hide)

[chironex]

In Star Trek this was referred to as a Dyson Sphere. The idea that there was no gravity was heavily refuted when the Enterprise almost got stuck to it...

[chironex]

AT-43 also had dieselpunk-inspired factions:
http://www.chuck-a-con.net/AT43KingBuggy.jpg
http://nordovest3m.altervista.org/images/at43.jpg

The latter are highly prized by Weird War Two gamers looking for Russian forces.

[Atterton]

A Dyson sphere is something slightly different.

[chironex]

Yes, a Dyson sphere is made of matter, and so has mass, and therefore gravity. This sphere must be made of energy.

[Shadow Of The Tower]

Its not a Dyson sphere because it has no sun inside it and its uniformly filled with atmosphere so the mass is evenly distributed and there is virtually no gravity to those inside it. (although near the ballon wall there is a small degree of gravity pulling inward towards the center of mass.)

The sun of suns is not a star but a large fusion reactor so there is no central mass to orbit, only a vague center of mass provided by the mass of the atmosphere itself. 

The shell of Virga is woven from carbon nantubes and since it completely surrounds all the occupants its mass pulls outwards against the pull of the mass of atmosphere and if anything cancels it out.

[chironex]

[leaves discussion until he can find an astrophysicist]

[Atterton]

Try looking underneath the sofa cushions.

[Shadow Of The Tower]

Well, I'm not a astro physicist but I grew up with one and studied it some in college.

Just think of it this way,

When you stand on the surface of the earth all the mass is below you so you feel it pulling you down, but if you somehow got deep into the interior, you would have mass above you as well as below and thus would feel less weight.  Assuming you had a habitable area at the center of the earth, you would be weightless because you would have an equal amount of mass pulling you in all directions. It would be impossible to fall because every direction would be up.

Since the fictional air filled ballon world of Virga has much less mass the area in the center of null gravity is much larger. The only truly weightless area would be at the center but for most of the volume there would be so little gravity you wouldn't notice it.  In the books the inner surface of the ballon is coated with miles of ice and I gather that is where most of the mass of the "world" is, which would further help to create a weightless interior sense most of the mass of the world would be surrounding you, even at the rim.

In Star Trek this was referred to as a Dyson Sphere. The idea that there was no gravity was heavily refuted when the Enterprise almost got stuck to it...

The Dyson sphere of course would presumably have a great deal of mass but an extremely low density since its basically a very thin shell around an immense amount of volume.  Since gravity is proportional to the

objects mass and your distance from the center of that mass

  you would be nearly weightless on either the inner or outer surface since you would be many hundreds of thousands of miles away from the center of mass of the system. 

With a traditional dyson sphere the mass of the whole thing would be equal to the mass of our entire solar system and the center of mass would be at the same location that it is in our solar system, the sun (or more precisely, very near the sun, the other planets pull the sun slightly away from the geometric center, this is the "wobble" that we use to detect alien planets)  What this means is that pull of gravity towards the center is exactly the same as the pull of the sun on our bodies. Sure, it exists but the pull on something as small as a person is so tiny that we don't feel it and its nearly immeasurable, although technically we are slightly heavier at  midnight than we are at noon. The same is true for the effect of the galactic core on the earth. In my physics class we actually did the math and found that our physics teachers body exerted more force on the earth than the so called doomsday alignment that is supposed to happen sometime this year. This was actually a question on the final test

 The only way to keep anything attached to the inner surface of a Dyson sphere would by either having a supper dense shell or by using artificial gravity generators, which was probably why scotty was able to crash on the surface. The enterprises's problem wasn't the gravity but the tractor beams that where pulling it inside. (Great episode BTW)

[chironex]

  Assuming you had a habitable area at the center of the earth, you would be weightless because you would have an equal amount of mass pulling you in all directions. It would be impossible to fall because every direction would be up.

At a perfect spot? What happens if you're closer to one side than the other?

The Dyson sphere of course would presumably have a great deal of mass but an extremely low density since its basically a very thin shell around an immense amount of volume.  Since gravity is proportional to the

objects mass and your distance from the center of that mass

  you would be nearly weightless on either the inner or outer surface since you would be many hundreds of thousands of miles away from the center of mass of the system. 

This point doesn't seem to reinforce the first point exactly.

The only way to keep anything attached to the inner surface of a Dyson sphere would by either having a supper dense shell or by using artificial gravity generators, which was probably why scotty was able to crash on the surface. The enterprises's problem wasn't the gravity but the tractor beams that where pulling it inside. (Great episode BTW)

Must... find... encyclopedia... even though mine predates Voyager I'm sure this is where I heard of it... Unless I sold it...

[Atterton]

Supposedly anything inside a hollow sphere would be weightless at any point, as the pull from the different areas would negate each other. At the outside you should still feel a gravitational pull, but as the mass would likely be very small, it wouldn't be much.

[chironex]

Well that's what it says on "guess-which-opedia" but I still say there must be some variation for being closer to one side than the middle. It also says the name refers to a number of concepts, the item in question being called a Dyson shell. No mention of standing on the outside, although you do have a star in the middle (though it may have issues with drifting with no relation to the stars movement at all!)


It's the least plausible on the list.

So why would anyone build this balloon place, and how is a Niven ring supposed to work? Where is its centre of mass?

[Atterton]

The idea of a Dyson Sphere is that you can catch all the energy of the star in the middle. Though a Niven style ringworld does seem more useful, if you want gravity.

[Shadow Of The Tower]

(though it may have issues with drifting with no relation to the stars movement at all!)

This is would indeed be an issue. You would have to have some kind of system for moving the shell, or the sun. Ring worlds have the same problem because they a rigid ring they are not actually orbiting the star and are inherently unstable. This comes up as a major plot point in the second Ring world book.

The idea behind a Dyson sphere is if we presume that faster than light travel is not possible then any civilization that doesn't destroy itself will eventual expand to the point where it needs more space and energy than can be provided the planets in its home solar system. A Dyson sphere would have billions of times more surface area than a planet and it would capture 100% of the suns energy which presumably is the most powerful source of energy it is possible to ever have in a single solar system.

The giant air filled ballon in the Virga books is only planet sized rather than solar system sized and orbits a star like a regular planet would. (even though the people who live inside have no way of knowing this)  Its center of mass is at its central point just like it would be for a very small gas giant. There would be a force of gravity pulling all objects inward to this point but because of the aforesaid reasons it would be a very weak force that would decrease in magnitude. In the book this is used to set up a series of convection currents that move air and material around in the "world" The small artificial "sun" is located at the center, as it heats the air that air becomes less dense and rises away from the "sun"  The shell of the ballon is in contact with space and is very cold and so when the air reaches the edge the air cools, water condenses out and freezes to the shell. The cool air becomes more dense and slowly descends back towards the center of the world, when the ice gets thick enough for the weak gravity to pull it loose from the shell it falls inwards towards the sun in vast icebergs that melt and provide water for the inner parts of the world.

Supposedly, according to the author a world like Virga would be much much easier to build than a Ringworld or Dyson sphere. As to why you would want to do that....well, that is one of the central mysteries that make up the plot of the books

[Captain Shipton Bellinger]

...The shell of the ballon is in contact with space and is very cold and so when the air reaches the edge the air cools, water condenses out and freezes to the shell. The cool air becomes more dense and slowly descends back towards the center of the world, when the ice gets thick enough for the weak gravity to pull it loose from the shell it falls inwards towards the sun in vast icebergs that melt and provide water for the inner parts of the world.

I'm not entirely convinced by this scenario on a number of points. Let's assume that somehow there is a gravity gradient between the centre of mass and outer envelope (big assumption!) sufficient to allow a weak convection. Let's also assume that irradiation from the internal 'suns' keeps the inner surface of the envelope warm enough to prevent the atmosphere from freezing but not too warm to allow ice to form (this reduced temperature gradient would further weaken any putative convection).

Inside a hollow sphere convection takes a cellular form, with adjacent uprising plumes being surrounded by downdraughts.

Ice is a fairly good insulator, so miles of it should keep the inner surface relatively warm, which in turn means a smaller temperature differential between the rising (moist) air and the condensing surface. With a smaller temperature differential the phase transition from water droplets to ice is likely to happen before the ice surface is reached, preventing ice build-up beyond a certain point. The snow/hail thus formed should either loosely accrete to the ice in the middle of the convection plumes or fail back to the core in their surrounding downdraughts. The interior of the ice shell should look like the inside of an anechoic chamber made of snow.

With little to no gravity to compact the snow on the shell hard ice could not form.

And lastly, assuming that there were mechanism to overcome all the above: Why would gravity be strong enough to attract the ice sufficiently to overcome its structural integrity but not really affect anything else inside the sphere? After all, there really is no net attraction between a spherical shell and a point mass inside it.

Virga sounds like an interesting scenario, sort of part way between a Dyson sphere and the gas torus around Levoy's Star in Niven's The Integral Trees. But, within certain bounds, I like science fiction to obey known physics.

[chironex]

The idea behind a Dyson sphere is if we presume that faster than light travel is not possible then any civilization that doesn't destroy itself will eventual expand to the point where it needs more space and energy than can be provided the planets in its home solar system. A Dyson sphere would have billions of times more surface area than a planet and it would capture 100% of the suns energy which presumably is the most powerful source of energy it is possible to ever have in a single solar system.

The original Dyson sphere was a spherical pattern of solar power satellites around the sun at about that distance. Not going into detail the difficulties with this idea, encasing the sun in a shell that wide would use all the matter in the system just to build one 3m thick (requiring a material with compressive strength higher than any known or theorised substance!), cut off any further light getting outside, and of course you won't be able to live on either inner or outer surface so unless your photovoltaic surfaces are transparent and you can import another world from another system. Leading both Dyson shell and balloon world of course to the idea of the Big Dumb Object because if a civilisation could- would they need to?

With little to no gravity to compact the snow on the shell hard ice could not form.

It happens on the noses of Alastair Reynolds lighthuggers, though you could put that down to the ships acceleration (what happens during the deceleration phase though? )

[Captain Shipton Bellinger]

With little to no gravity to compact the snow on the shell hard ice could not form.

It happens on the noses of Alastair Reynolds lighthuggers, though you could put that down to the ships acceleration (what happens during the deceleration phase though? )

I'm afraid that I am unacquanted with Lighthuggers, but a quick wiki-jaunt informs me that they generally sustain a 1g acceleration and, as we all know, inertial and gravitic frames are indistinguishable, so snow should compact to ice at about the same rate as it does on Earth. It would be subject to sublimation in the hard vacuum, though.

I now have to track down some Reynolds Revelation Space books. 

[Shadow Of The Tower]

I'm not entirely convinced by this scenario on a number of points

Those are good points!  I've never thought very much about the convection system, I've only looked at the world from a gravitational viewpoint.  You should write the author a letter.

Here is a page I found where the author describes some of the physics behind Virga, and interestingly enough, admits that his air circulation system has flaws but not precisely the ones you mention.

He does say that the skin of Virga actually is cold enough to freeze atmosphere but the convection cells move it around enough to keep this from happening, and the central sun is nowhere near powerful enough to heat the outer regions of Virga, after all, light is rapidly absorbed by air, just think of how red the sun gets at sunset merely from passing though an horizon distance of air so I think that you would have a rather strong temperature gradient after all.

I do wonder if the gravity gradient would be strong enough though for a hot cell to 'rise' rapidly enough to reach the edge before it cooled through radiative transmission so much that it stalled or broke up.

http://www.kschroeder.com/my-books/sun-of-suns/engineering-virga

And lastly, assuming that there were mechanism to overcome all the above: Why would gravity be strong enough to attract the ice sufficiently to overcome its structural integrity but not really affect anything else inside the sphere? After all, there really is no net attraction between a spherical shell and a point mass inside it.

I believe this is simply based on the way that the force of gravity between two objects is dependent on their mass. (as well as the distance between them of course)  After all, the force of gravity between the moon is strong enough to pull untold billions of tons of sea water out of place but the force between the moon and, say a person is nearly immeasurable at the same distance. The acceleration of of gravity of course remains the same regardless of mass but the weight felt is dependent on the mass.  A person or airship near the edge could only weigh a few pounds, a force that could easily be counteracted by convection winds (if they exist!) or propulsion but something the size of a mountain would still weigh millions of pounds even in that very weak gravity. I don't know if this would actually be enough to break loose the ice on its own or if it would only be enough to pull it inward after it broke due to other reasons (thermal expansion?, shifts in the shape of the outer ballon?)

Of course this would also be a problem if the rim ice is low density snow rather than 'icebergs' described in the book (I'm imagining it kind of like the condensation you used to get in refrigerators)

He also describes enormous icicles but even though I can believe that the micro gravity would be enough to pull mountain sized chunks of ice I don't see it pulling a thin layer of water 'down' an icicle fast enough for it to freeze near the point and grow the icicle, or why there would be water on the surface of this ice that was warmer than the ice itself, unless the ice is temporarily partially melted by one of the many small 'suns'......

I don't know....I didn't invent it. The stories that I write take place on planets for a reason, we know they work!

Again it makes me think of Ringworld and how originally it was a very simple construct without much in the way of mechanisms needed to regulate it and then as Niven discovered flaws ( or had them discovered for him by fans!) he had to create an increasingly complex system of machinery to keep it running ( attitude jets, a system of moving sea floor mud to the top of the rim mountains to combat erosion, coronal lasers, etc)