1. TimHarris
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    TimHarris Senior Member

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    Dealing with zero gravity

    Discussion in 'Plot Development' started by TimHarris, Oct 25, 2012.

    I am writing a science fiction novella. One of my main concerns being spaceships in zero gravity. I originally wanted to write my story in a zero gravity setting, but this places certain constraints on what I can do with my story, which I really dont want to deal with.

    I do not like the idea of having artifical gravity without a proper explanation either, so what you think would be a good approach to this? I am a bit stuck on finding an explanation as to why the ships (at least the largest, named Class A vessels in by story) can have artificial gravity. Does anyone have any physics knowledge and could give me a couple of pointers as how how I could explain having artificial gravity onboard my ships? I am af fan of hard science fiction, so I want the explanation to be at least somewhat reasonable. I dont want to do centrifugal force based gravity either, as that also puts constraints on ship design, so I am kinda stuck right now.

    Hope we can get a little discussion going :)
     
  2. AnonyMouse
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    AnonyMouse Contributing Member Contributor

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    I think the only proven way to fake gravity is inertia. If you don't want to go the centrifugal route (which is a form of inertia-based faux-gravity), you could use the ship's linear acceleration instead. Imagine the ship is a skyscraper, where the ship's bow is the top of the tower. As it accelerates (goes up) the occupants will be pressed down. If we assume the ship is accelerating halfway to its destination, then flips 180 degrees and decelerates for the second half, this will create artificial gravity.

    However, there are some problems with this. Firstly, the transition in the middle will be awkward. During the "flip" there will be no gravity. I hope you remembered to bolt down the furniture and shut the lids on the toilets. ;) Secondly, this makes for odd ship design. A ship built like a tower can't land like an aircraft and now your spaceports look like downtown Manhattan. Thirdly, this uses up a lot of fuel, since the engines must be on constantly (except during the flip). If the ship stops accelerating, you lose gravity, so coasting is not an option.

    Personally, I would just go with some type of gravity-producing technology. Like FTL, it's so commonplace, I don't think most readers will bat an eye at it. If you truly want to go hard sci-fi, I think inertia-based gravity is your only option... unless someone knows something I don't. Cogito might have something up his sleeve. :)
     
  3. JamesOliv
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    JamesOliv Senior Member

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    I know there are theoretical models which involve the use of inertia. Essentially, all or part f the craft rotates in such a manner that it simulates the rotation of the earth and creates an artificial gravity environment.

    But, not a physicist and I dont want to deprive you of the opportunity to google that theory.

    One thought would be the use of magnets. Imagine if you wore a magnetized jump suit and the floor had an opposite charge. Not enough power to force you against the floor, but enough to ensure you could walk on the floor and that a dropped (metal) tool would likely fall to the ground (or stick to your clothes). That would kind of give you the best of both worlds. On the one hand, you can walk through a hallway as you would in an artificial gravity environment. You can run and do jumping jacks. But, your drink could still come out of the pouch in floating globs.

    The magnetic suits would also (I imagine) help prevent the adverse effects zero gravity has on muscle tone.
     
  4. Gilborn
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    Gilborn Member

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    I'll admit I'm not a big reader of Sci-fi; however I love to watch it almost exclusively. I always thought it would be cool to build a ship that utilizes an internal lining of dark matter that could be phased in and out of our exact space time. This would allow for lightening the ship during launching and landing (if you want your ship to land on planets) it would also insure that the dark matter can be removed in case of explosions. The utilization of dark matter would allow for disproportional amounts of gravity, which is nothing more than the attraction between two objects in space, compared to the physical space it would occupy. In short by having dark matter floors you can insure gravity regardless of exterior conditions, unless you were to get to close to a gravity well, such as a black hole.

    Best of luck, I think making sure you can at least basically explain your technology is a great way to add depth and realism to your story. I personally read fantasy and accept anything that's thrown at me, but when watching sci-fi I expect a certain level of scientific explanation. Not just it is the future and we have blank technology.
     
  5. Warrior of Light
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    Warrior of Light Member

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    You know superconductors?

    Certain ceramics like yttrium, barium or copper oxide become superconducting when exposed to ordinary liquid nitrogen.
    Now liquid nitrogen cost as much as ordinary milk (+ for your economical realism of ya world).

    By cooling the ceramic to minus 200 degree cenegrade, you're effectively creating a new state of matter. The new material loses all its electrical resistance and becomes superconducting - able to induce powerful magnetic fields.

    Place a magnet on top of the superconducting ceramic and it begins to float. This is the Meissner effect.

    Explanation:
    The presence of the magnet on top induces a secondary magnetic field withing the superconductor and the two magnetic fields repel each other, giving you the ILLUSION of anti-gravity, but it fulfills the requierements for floating. This causes movements without any friction whatsoever.
     
  6. captain kate
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    captain kate Active Member

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    Bear in mind that exposure to extended periods of zero gravity is detrimental to the human body. If the travelling calls for long periods of time, then you'd be kind of forced to create anti-gravity to cover the health effects. I suggest doing a google search on the effects of zero gee on the human body also as part of your writing process.
     
  7. TimHarris
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    TimHarris Senior Member

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    Thanks for the replies so far. I like the intertia based gravity quite a bit, but the big problem with that is that my story is only taking place planetside very briefly. It's set a few hundred years into the future where humanity has started exploring another solar system. Most of my story will be taking place onboard the ships themselves. Basically I am ignoring the whole lasers, fighting in space and colonizing placets-part of science fiction and will be focusing more on how humanity will behave when they are in an environment isolated from the rest of the human race, with a military government in control of the society. An environment as hazardous as this will often attract some of the most morally twisted people you can find, and when this is combined with advanced technology, heavy weapons (No! no lasers) and a lack of a proper justice system, things will get interesting.

    It is important to me to get the technology right though. It's only a few hundred years into the future, so I dont want the technology to be too advanced, but I realize I need to make a few assumptions as to what kind of technology they would have so that I can get an interesting story, even though the focus is more on the political and social aspects of such a setting.

    The dark matter route seems interesting though. I was playing with the idea, and came up with having a quantum core installed onboard some of the ships. These cores would be filled with dark matter, that could be distributed about the ship where you needed it. This could also make for some interesting plot development if one of these cores should fail.
     
  8. robertpri007
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    robertpri007 Member

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    I don't understand why you would want to get bogged down in such detail. I doubt you will try to explain the propulsion that exists in the future. There is no way for you to know. Just mention they are glad for the artificial gravity systems and press on. The story is about the people, right? Why open yourself to criticism from readers that know far more. But if this story is more about spaceships than the passengers, then good luck.

    BTW: as a retired airline technician, I cringe every time I see a movie with about airplanes. Who was the technical adviser?
     
  9. TimHarris
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    TimHarris Senior Member

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    Well I'm a sucker for details. Unless something in a story makes sense, at least on some level. I will get generally get annoyed while reading it, and I will be having the feeling for the rest of the story that "Meh, this could have been better". So that is why I want to go into detail on the technical aspects, even though my story is not strictly about that.
     
  10. Warrior of Light
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    Warrior of Light Member

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    You won't be always able to have realistic explanations for technology of a Type-II-civilization (yes, a civilization that directly uses energy from a star and controls it, has a good reason to explore other solar systems and is called a "Type-II-civilization") since this is the work of the greatest theoretical physicists nowadays.

    But we won't reach Type-II anytime soon, we would need a thousand years.

    Type-I in a hundred years? -Yes! A planetary civilization that controls the weather, earthquakes and even vulcano. They would mainly travel in their own solar system though.
     
  11. psychotick
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    psychotick Contributing Member Contributor

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    Hi,

    The accelerative inertial system mentioned is the only fake system I know of that will mimic gravity perfectly, but as said it has problems not least the fact that you have to maintain acceleration / deceleration all the way. That has an impact on the speed of the journey. For example if you accelerate at one gravity, or ten meters / sec / sec, it will take you slightly over a year to reach the speed of light, and I assume that if you aren't going to have true artificial gravity you're also not going to exceed light speed and upset relativity.

    So now assume that your destination as Alpha Centauri, lets say 4 light years away. If you accelerate at one g and decelerate at one g and reach light speed the trip takes five years, three of which are without any gravity. Alternatively if you want to have gravity all the way there, then you have to accelerate and decelerate more slowly and the trip takes longer.

    Magnetics are a compromise, but the rate of decay of a magnetic field with distance is far greater then the rate of decay of gravity as we experience it on Earth. What that means is that a magnetic attraction is very strong at very short distances, but at even slightly longer ones, an inch or two, there's almost no obvious attraction. So it's a lot of hard work to lift your magnetised boot the first half inch off the floor and then no effort at all to lift it the rest of the way. Plus of course, what would be the effect of an intense magnetc force on the ship's instrumentation?

    Centrifugal force is the better option even though you don't want to do it. One thing to remember with it is that the effective force pushing you out towards the rotating hull is greatest near the hull but non-existent in the centre. On a small diameter ship this would mean you could experience a goodly pull around your feet but if you made a decent high jump attempt, could find yourself flying.

    As for the dark matter phasing, I don't know how this would work. But estimates are that dark matter comprises eighty percent of the universe (fifteen percent is dark energy and the rest is the stuff we see). So even if you could phase the eighty percent into existence inside the ship's structure, all you'd do is multiply the ship's mass by a factor of sixteen. The gravitational effect of a normal hull would be almost nothing, and sixteen times almost nothing would be not a lot more.

    If you wanted to increase gravity by simply increasing the mass of the ship, you'd need something like neutronium, with a denisity thousands or tens of thousands of times greater than that of normal metals. The problem with this is, that all that extra mass would make it very slow for the ship to accelerate, decelerate and turn.

    There was one other system I once saw on a movie which could be interesting. The use of fans on body suits. The fans constantly work to push the feet away from the body, and if you're oriented correctly, towards the floor. And you could put more fans on wrists etc to give resistence to arm movements. But it would take a lot of practice to use the fans correctly, because if you fell over you'd actually find yourself flying by fan propulsion. Also loose pieces of paper would be a problem.

    Maybe a combination of fans, magnets and centrifugal systems would be your best option.

    Cheers, Greg.
     
  12. TimHarris
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    TimHarris Senior Member

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    What if you kep antimatter in place by a magnetic field below the floor of the spaceship? Would that attrack all matter in the ship to simulate gravity? I dont know all that much about this one though, but I think it would be worth it to at least research for me if I happen to get the time.
     
  13. captain kate
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    captain kate Active Member

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    Sometimes the devil is in the details. You get yourself too bogged down in them, and it'll prevent you from going anywhere. There isn't a science fiction novel-including Chrichton who wrote on tech almost developed-that's 100% accurate on the technology. The biggest part is to craft a story that people will remember, not go "Oh, wow! That technology is realistic!" That aspect will only get you so far...the characterization in many ways means far more then world building-which is important in its own right.

    Just give the ships anti gravity, and more on to your character arc-that's that the reader will remember more then whether you got it "right" tech wise.
     
  14. psychotick
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    psychotick Contributing Member Contributor

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  15. Cogito
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    Cogito Former Mod, Retired Supporter Contributor

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    If you can't use a delta-vee approach (rotation or constant acceleration) approach to shipboard "gravity", for gosh sakes don't BS a physics rationalization! Just call it artificial gravity and leave it unexplained. All the reader needs to know is how it behaves.

    You don't need to show your ignorance of physics by shovelling a pile of manure. Many science fiction readers are not only knowledgeable about theoretical physics, but actual experts. You won't impress them with half-baked theories.
     
  16. Edward M. Grant
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    Edward M. Grant Contributing Member

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    Only if you plan to live on high-gravity planets afterward; free-flying habitats, for example, can have any gravity level you want and there's no good reason for it to be as high as Earth's. Besides, by the time interplanetary travel becomes commonplace, we'll be have the technology to redesign our bodies to eliminate any issues.
     

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