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» Hatrack River Writers Workshop » Forums » Open Discussions About Writing » Artificial Gravity

   
Author Topic: Artificial Gravity
Osiris
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Hi,

I'm working on an sf piece that includes some arcologies on the moon as one of the settings. The setting for the story is futuristic, in that man has advanced enough for routine space travel and industrial colonization within the solar system but not beyond that. I'm not sure if that'd put the year around 2100, but I'm flexible on that.

What I really want to know, is there a way to generate artificial gravity for these moon arcologies that doesn't involve something impossible (like accelerating the Moon's rotation)?

If not, I suppose I could change the setting to orbital stations around the moon (but I don't want to do that), or perhaps the colonists just have to spend a lot of time exercising, maybe their habitats are in some kind of rotational building. I could use any ideas that would make a permanent moon colony feasible from a health and gravity point of view. Thanks!

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MattLeo
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Easy, you just reverse the polarity of the neutron flow through an unobtanium gravity crystal.

Magical AG is almost always assumed except in the very hardest of hard sci-fi, and usually even then. There's always something that isn't explained, and if it isn't AG, it's how they can do all the things they do without AG.

The only reasonable substitute for gravity known to science is acceleration, but it's probably not reasonable to build an entire lunar community on some kind of spinning ring. Even if you could, it would be poor engineering to have a design where everything would fall apart in a mechanical failure. It'd make more sense to build most of the community around the assumption low-g, and then fix any problems that arise. People would probably work or live in centrifuge-like buildings, or run on an exercise wheel for an hour every day.

I've just been through this mental exercise for *Keystone*, in which I assume AG, but have to work out the impact on space architecture. I've decided that space installations would be enormous, taking advantage of AG to provide simulations of Earth-like conditions for their inhabitants. The high volume of atmosphere would also buffer any changes in atmosphere chemistry, even giving the station a margin of safety in the case of a small hull breach.

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extrinsic
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Increase effort by adding muscle resistance prosthetics and weights to colonists' work outfits.
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Osiris
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As I a scientist, I can't help all my science wanting to be able to stand up to some measure of scrutiny. You're right though, I think most readers don't worry too much about magical gravity.

Extrinsic, that's the direction I've been leaning, rather than AG, some sort of gear that creates resistance.

What do you guys think about magnetic flooring with clothing that has some kind of metallic threading woven into it? Could you then modulate the magnetic pull through some mechanics in the flooring?

Damn it Jim, I'm a biologist, not a physicist! [Smile]

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extrinsic
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Magnetic fields would cause unwanted complications for other electronic systems, then requiring shielding, adding complexity to systems, and making for further system complications down and upstream.

A worksuit would only need resistance bands along long bone structures and major body structures: legs, arms, waist, knees, and elbows, weighted shoes, shoulder weights. Leave head, neck, spine, hands, fingers, and ankles free to move for safety and dexterity's sake.

Worker resistance, protests, rebellion, or outright revolution to the suits could cause circumstances that add to plot complications.

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rstegman
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Have a particle accelerator built deep below the colony. It creates an "artificial black hole" or "artificial gravity" that gives earth level gravity. Once a week or once a month, you can have them turn it off for maintenance at which time people will move heavy materials. Also have the gravity fade out a short distance from the protective bubble.

Having it off a day every once in a while makes sure people can operate effectively should the system fail entirely. One might have the old folks home at the edges of the gravitational field where the lesser gravity is easier on their bodies.

Your characters don't have to know how the gravity works, just know the effects. If one of your characters is in the know, you can pawn it off as something about accelerating large masses of high atomic-number anti-particle atoms. What we know about anti-particles or their atoms gives you a whole lot of wiggle room.

As for the time frame, "long long ago, far far away" always works for getting away with things. It is sort of embarrassing that we have not met the time frames of the writers half a century ago.

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Osiris
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rsteg, something like that occurred to me as well, I just didn't know if it was more of a science-fiction or science-fantasy concept.

Given my setting takes place about a century or so in the future, I'm not sure if that kind of technology would exists or not. More research warranted, I suppose, but you've all given me some leads, so thanks!

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rcmann
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Larry Niven used the idea in his "Protector" book of having a stable mass of neutronium to generate an artificial gravity field. Neutronium being the state of matter where atomic nucleii are packed edge to edge, it's as dense as matter can be without becoming a black hole. It's possible that modern science might be able, within the next century, to improve our containment technology to the point that we could manage to keep a small amount of the stuff stable. Maybe. Of course, that would also add a potential plot point because of the constant danger of the containment failing.
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Osiris
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I don't want to overstate the importance of getting this right, because only half the story only takes place on the moon, and the gravity isn't important to the plot, it is just important for the authenticity of the setting (since I've written most of the scenes already and they are all acting like they are under Earth gravity).
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Osiris
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Thanks rcmann. That is another idea worth exploring.

quote:
Originally posted by Osiris:
I don't want to overstate the importance of getting this right, because only half the story only takes place on the moon, and the gravity isn't important to the plot, it is just important for the authenticity of the setting (since I've written most of the scenes already and they are all acting like they are under Earth gravity).


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Robert Nowall
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I usually fudge things with a reference to "Agrav" or somesuch, if I think normal one-gee gravity (more or less) is needed in my setting, usually a space station. (The term is an obscure reference-slash-tribute to works by Asimov; it worked its way into a story of mine (and my subsequent SF terminology) that I was writing when he died.)
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Robert Nowall
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Carelessly didn't add my further thought---the actual means of "how it happens" is less important than "it happens." This on the principle that you don't think of the history of the car, or what the names of them actually mean, or where these names came from, when you're driving a car. (You don't unless you're very pedantic.)

And, more importantly, your characters won't sit down and explain how it's all happening...

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MartinV
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Just started reading "The Moon is a harsh mistress" by Heinlein. Most of the story evolves on the Moon and the gravity issue is a constant theme. I recommend taking a look.

And as a physicist, acceleration really is the only way to mimic gravity unless you have something not completely true in the pot. Most books and movies will silently avoid the problem. You could simply have a character say "Back when gravity was still an issue..." The reader will understand that something was done about it but they don't need to know the details.

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KayTi
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I love The MOon is a Harsh Mistress, my favorite Heinlein book of all time, glad you mentioned it, Martin.

I just want to point out that a century ago, much of technology that we completely take for granted today would be so different as to be considered almost magical. Credit cards that swipe at cash registers to pay for things? Email? Computers in general? Sure, we don't have hovercraft and that teleportation technology is way behind schedule, but a LOT of today's world would seem very very very crazy to someone just 100 years ago.

You write science fiction. Don't be afraid of the fiction part of it!

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rcmann
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We do have hovercraft. They aren't common, but we have them.
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MartinV
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Hell, I'm thinking of building one.
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Robert Nowall
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As I recall, hovercraft never caught on as cars because they're hard to steer and even harder to bring to a stop. If you're building one for water use, they'd be okay---land use, no, water, yes.
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MartinV
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Water and particularly deep snow.
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Robert Nowall
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For some of the science-fictiony things that were imagined, that would be useful to us, but somehow hasn't made it to market yet...well, there's usually some technical problem.

Like it's not known or believed to be physically possible (matter transmission, or, of course, artificial gravity), and, therefore, waits on some new discovery that could come tomorrow, or maybe never come.

But there's also technical problems. You've no doubt seen news reports about the electric car---the main problem with that has always been the battery, which just can't compete with the range between refueling that gasoline gives. (This problem defeated Edison.)

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MartinV
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If you want to see some brilliant and strange vehicles, go to youtube and type in:

ekranoplan

russian ufo saucer technology

It will definitely get you thinking...

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Brendan
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Osiris, what is the issue that you really want to overcome? I can think of a few.

Muscle Wastage - resistance exercise and future drugs should have this one wrapped up

Bone Wastage - this requires impact exercise, not just resistance, so the magnetic floors is a good idea. (And I wouldn't worry too much about the electrical interference issues, because by that time most electronics would probably be photonic based or quantum (which needs shielding anyway). Drugs are also the likely cure, anyway.

Slow falling/ fast reaction time to falling etc - a feature that I wouldn't want to be eliminated in a moon story.

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