# Non-rotational artificial gravity



## Sean16 (Oct 30, 2019)

Hey there, hoping to write a series of short sci-fi stories but I'm a bit indecisive over which way to go in regards to artificial gravity.

The time period I'm generally aiming for is the 2240s, so it is a fair bit into the future, but humans have yet to leave the Solar System and FTL travel has not yet been perfected; there's a bit of a stagnation. I've recently taken a liken to more hard, mundane sci-fi, which resorts to using less fantastical technology. Robert Heinlein's _The Moon is a Harsh Mistress_ really intrigued me over the colonists' use of centrifuges and weights.

I'm now considering going this route, not just in relation to surface colonies but also spacecraft, but I'm unsure if the 2240s is a little too far into the future to not have some kind of non-rotational artificial gravity generation (like in Star Wars, Star Trek, etc). I was originally going to go for this as it would make the setting a little less confusing and more convenient for my characters, but now the idea fascinates me. I have no scientific background and my stories lean more towards social science fiction, but I'd like to portray the future as realistically as possible.

Thoughts? And are there any examples where non-rotational gravity generation is portrayed in a way that at least "semi"-plausible?


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## Bagpuss (Oct 30, 2019)

Peter F Hamilton's novels "Pandora's Star" and "Fallen Dragon" both have starships with rotating sections.

The Babylon 5 TV series also has ships with rotating sections, and the station itself rotates. B5 production did make an effort to get the science of that right, so you could look at that as well.

If you're going to go with artificial gravity then you're probably going to have to hand-wave how that gravity gets produced. Arthur C Clarke did a nice version of artificial gravity on Odyssey 3001 (from memory) where the AG was linked to the space ship's propulsion system.


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## CupofJoe (Oct 30, 2019)

There is probably some mathematics that proves it is possible, but it probably the same type of maths that says wormholes can be created and FTL is possible. when I write I tend to bend the knee and take it as understood by the reader that artificial gravity just is and hope no-one notices the wobbly bits...


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## Star-child (Oct 30, 2019)

Agree that artificial gravity strongly implies a reactionless drive. But that doesn't mean there is automatically going to be interstellar travel, or much of it. The solar system should be plenty crowded.

Otherwise, how about garments that are attracted to the floor or repulsed from the ceiling, simulating weight?


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## Foxbat (Oct 30, 2019)

Eletrostatic precipitators could be a possibility. They work by applying a voltage that creates an electrostatic charge to attract dust particles to charged plates. You could extrapolate that idea and have a floor providing electrostatic attraction that, in turn hold the person's shoes/boots in place and preventing them from floating around. These plates could be under designated pathways throughout the ship. Stray from the pathway and you're floating around in zero G.


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## Venusian Broon (Oct 30, 2019)

Personally I think 2240 is far too _early f_or useful non-rotational artificial gravity to appear. At least in the sense of people walking about linear decks, a'la Star trek or Star Wars.

Speaking as a physicist, until we make breakthroughs in quantum gravity (and I have grave reservations we will make such a breakthrough for a very long time), it's hard to see any easy solution. So ignoring any hand-wavium solution, if you want to tie it to what we know right now:

So you can rotate a spaceship to generate centripetal forces as you state. This is by far the lowest hanging fruit. 

Or you could, as Alastair Reynolds does in his _Revelation _series have 'lighthuggers' that generate a 1G linear thrust - hence everyone in the 'tower ship' gets a 1G gravity field. Of course, this ship will need to switch off and change direction to actually stop somewhere _and _his engines that produce this 1G thrust are really powered on magic and not realistic. But the principle is sound.

Then you could, I suppose rely, rather than on rotation or acceleration, use mass. Why not have an artificial micro-black hole in the centre of the ship? (Could also be a great way to generate energy). Ship would likely have to be huge though, and I can't tell you what mass of black hole you'd need to generate 1G at a reasonable safe distance, I would need to crunch the maths. 

Note though, one of the reasons I think we won't get quantum gravity anytime soon, is that we need direct experimental evidence of interactions with black holes, and they are either very far away, or no one really knows how to make them. So by the time we can manufacture black holes...perhaps we will have solved that mystery and have derived more fascinating solutions.

Note that both rotational and black hole methods suggest craft should be round or spherical. Floors should be curved and concentric. The Death Star in Star Wars should really have had layers of concentric floors, rather than be stacked like a space office block, all linear and euclidean right-angled. I mean, it should have been big enough to generate it's on moon-like gravity field, with all the mass it had!

Personally I wouldn't worry about it. Virtually every SF writer handwaves an answer to get something that they want. 

Including me - I have a great explanation to give my characters 1G fields in space...but you will have to wait till I publish


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## Daysman (Oct 30, 2019)

Would you want to explain it, albeit briefly, or establish an easily understood technical term, something equivalent to _gravity plating_?

My favourite non explanation for artificial gravity is from Samuel R Delaney's _Triton_:



> ...all the particles in a bunch of trilayer iridium/osmium crystalline sheets, spaced about under the city, are madly orbiting in tiny circles of one point seven two seven the diameter of a rhodium one-oh-three nucleus. The magnetic resonance keeps the crystals from collapsing in on themselves. The resultant mass, and the gravity set up, is increased several hundred million-fold in one direction, because of the wobble...


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## Venusian Broon (Oct 30, 2019)

Daysman said:


> Would you want to explain it, albeit briefly, or establish an easily understood technical term, something equivalent to _gravity plating_?
> 
> My favourite non explanation for artificial gravity is from Samuel R Delaney's _Triton_:


Great quote, lovely handwavium!...but I remember really disliking that novel. 

Perhaps, now 25 years into the future I might appreciate it differently.

Maybe when I'm past my current physical pile of books to read (at about 60+) I _might _think about giving it another shot!


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## Sean16 (Oct 30, 2019)

Daysman said:


> Would you want to explain it, albeit briefly, or establish an easily understood technical term, something equivalent to _gravity plating_?
> 
> My favourite non explanation for artificial gravity is from Samuel R Delaney's _Triton_:



Thought about going the gravity plating route but have never found anything that properly explains how it actually works, so have been hesitant to go that way.


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## Venusian Broon (Oct 30, 2019)

Sean16 said:


> Thought about going the gravity plating route but have never found anything that properly explains how it actually works, so have been hesitant to go that way.


You won't find anything right now regarding plating! Partly hence my scepticism about near future tech that could.

For magic floors that 'emit' perpendicular lines of gravity, there's the breaking of Newton's third law to contend with. (And actually, if you have 'gravity plating' you should have immensely powerful engines that work on the same principle...and no doubt some perpetual motion devices...

...I'll have think about that final thought though...!)

So if you are going a more 'realistic' route, rotation seems most probable. 

Of course, as others have pointed out, one may use other forces - electric or magnetic - but I am sure there are a heap of problems that might make these impractical.

Honestly, unless you want to write hard SF, I'd just to ignore the details and skate over any explanations.


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## hitmouse (Oct 30, 2019)

The black hole thing is interesting. If a ship contained one small enough to produce a 1g force then presumably the radius of the 1g effect would be of quite limited thickness, which would produce significant limitations in its utility.


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## Daysman (Oct 30, 2019)

Sean16 said:


> Thought about going the gravity plating route but have never found anything that properly explains how it actually works, so have been hesitant to go that way.


Yeah, I was just talking about whether you might invent some self explanatory term that did the job in your narrative and allowed you to move on with the story...


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## Sean16 (Oct 30, 2019)

Daysman said:


> Yeah, I was just talking about whether you might invent some self explanatory term that did the job in your narrative and allowed you to move on with the story...



It's tempting! I'll play around with some ideas. So far the response to this thread has been good, so got a lot of concepts to fiddle with.


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