# How's gravity supposed to work on a sci-fi spaceship
**URL:** https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626
**Category:** Cafe Society
**Created:** [September 18, 2009, 6:27pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626 "2009-09-18T18:27:15Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Wakinyan](https://boards.straightdope.com/u/Wakinyan)
#### Post date: [September 18, 2009, 6:27pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/1 "2009-09-18T18:27:15Z")
I don’t watch science fiction much, aside of Asimov during my teens I haven’t read any sci-fi books. But to my surprise I got hooked on _Battlestar Galactica_ (no spoilers please!), and it got me thinking:
In the sci-fi universe, so to speak, is there a general understanding on why people don’t float around in spaceships, but walks on the floor, or at least, has somebody “explained” it in their own world? Not how it have to be done in reality, but how it’s supposed to work in the fictional universe pictured.
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### Author:  [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)
#### Post date: [September 18, 2009, 6:29pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/2 "2009-09-18T18:29:57Z")
Handwaving.
You can create gravity by spinning the ship and letting centrifugal force do the work. But most SF doesn’t bother with any explanation other than saying, “The artificial gravity is created by – wait! Over there! Is that an alien ship about to attack!”
If this bothers you, then you probably shouldn’t be reading or watching science fiction.
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### Author:  [@Brainiac](https://boards.straightdope.com/u/Brainiac)
#### Post date: [September 18, 2009, 6:32pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/3 "2009-09-18T18:32:19Z")
In 2001 a Space Odyssey the ships spin to create gravity.
On Star Trek, they have gravity, and jarring accidents every episode, but no seat belts or even strap hangers like the subway. You’d think they’d catch on. Or at least show someone killed by hitting their head on the desk corners.
The other convenience, from Buck Rogers onward, is landing on planets with atmosphere.
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### Author:  [@running\_coach](https://boards.straightdope.com/u/running_coach)
#### Post date: [September 18, 2009, 6:32pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/4 "2009-09-18T18:32:22Z")
Usually some form of artificially generated gravity.
ETA:To add to the above, some form of machinery or generator or plating made of ultradense materials.
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### Author:  [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)
#### Post date: [September 18, 2009, 6:40pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/5 "2009-09-18T18:40:53Z")
The gravity generators are designed to create a nominal “down” that corresponds with the decks of the ship. For convenience all decks are aligned the same way, so the crew doesn’t have to flip out of the elevators using hand-grips (or the elevator cars align themselves with the designated “down” of the deck they reach).
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [September 18, 2009, 6:44pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/6 "2009-09-18T18:44:43Z")
Usually, if there’s any explanation at all given (beyond just saying “artificial gravity generators”), it’s centrifugal force (to my knowledge, Babylon 5 was the only TV show to use this). BSG does have one ship that rotates and looks like it might use that for artificial gravity, but only one: My guess is that artificial gravity is a relatively recent invention, and that’s an old ship (but I don’t think it’s ever addressed in the show).
One detail we do know about Battlestar Galactica (and don’t worry, this isn’t really a spoiler) is that at least some ships have multiple different directions of artificial gravity, so some folks can be “upside-down” relative to others.
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### Author:  [@flodnak](https://boards.straightdope.com/u/flodnak)
#### Post date: [September 18, 2009, 6:51pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/7 "2009-09-18T18:51:33Z")
> [@Brainiac](#):
>
> In 2001 a Space Odyssey the ships spin to create gravity.
And in the novel 2010, the Leonov did not spin, and everyone floated around. When it was turned into a movie, somebody must have realized that this was going to be a pain in the rear to film, so the Leonov underwent a radical redesign to include a spinning section. The movie otherwise left me underwhelmed, but that little detail impressed me.
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### Author:  [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)
#### Post date: [September 18, 2009, 6:56pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/8 "2009-09-18T18:56:47Z")
Lack of Gravity is expensive to film, so they usually don’t bother with it. Read Heinlein’s essay on “Making Destination Moon”. It’s half a century old, but the Hollywood mindset (and the realities of movie production) haven’t changed. They HAVE filmed a handful of realistically zero-G movies, but outside of Destination Moon I still haven’t seen a movie to realistically portray low gravity as on the Moon. Or Mars.
Centrifuges were used as artificial gravity in **2001, 2010,** and **Aliens**. In principle, you can get artificial gravity by constantly accelerating a 1G, but nobody’s done it in the movies AFAIK. Everybody else evidently uses some futuristic Special Relativistic Physics to make artificial gravity. Heck, they’re already exceeding the Speed of Light, why balk at Control of Gravity? ( **Forbidden Planet, Star Trek, Star Wars, Battlestar Galactica,…** )
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### Author:  [@Mogle](https://boards.straightdope.com/u/Mogle)
#### Post date: [September 18, 2009, 8:16pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/9 "2009-09-18T20:16:07Z")
> [@Chronos](#):
>
> Usually, if there’s any explanation at all given (beyond just saying “artificial gravity generators”), it’s centrifugal force (to my knowledge, Babylon 5 was the only TV show to use this). BSG does have one ship that rotates and looks like it might use that for artificial gravity, but only one: My guess is that artificial gravity is a relatively recent invention, and that’s an old ship (but I don’t think it’s ever addressed in the show).
It should be noted that those ‘artificial gravity generators’ do exist in the Babylon 5 universe, it’s just that Earth doesn’t have the technology.
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### Author:  [@gallows\_fodder](https://boards.straightdope.com/u/gallows_fodder)
#### Post date: [September 18, 2009, 8:33pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/10 "2009-09-18T20:33:45Z")
> [@Chronos](#):
>
> One detail we do know about Battlestar Galactica (and don’t worry, this isn’t really a spoiler) is that at least some ships have multiple different directions of artificial gravity, so some folks can be “upside-down” relative to others.
Which episode(s) featured that?
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### Author:  [@alphaboi867](https://boards.straightdope.com/u/alphaboi867)
#### Post date: [September 18, 2009, 8:34pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/11 "2009-09-18T20:34:33Z")
> [@Brainiac](#):
>
> …On Star Trek, they have gravity, and jarring accidents every episode, but no seat belts or even strap hangers like the subway. You’d think they’d catch on. Or at least show someone killed by hitting their head on the desk corners…
And only once in the history of Star Trek did anyone ever think of using the artificial gravity generator to stop an intruder.
The Mirror Universe episodes of Enterprise; they were trying to stop a Gorn pirate from roaming around the ship and someone got he great idea “Hey let’s just turn the artificial gravity up really high where the Gorn is” adn the Gorn collapsed to the floor.
Star Trek: VI was the only time we ever actually saw the artificial gravity failing (on a Klingon battlecruiser) and the total chaos that resulted.
[QUOTE=flodnak]
And in the novel 2010, the Leonov did not spin, and everyone floated around…
[/quote]
Ah yes, the Soviets considered artificial gravity a decadent capitalist luxury.
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### Author:  [@Wakinyan](https://boards.straightdope.com/u/Wakinyan)
#### Post date: [September 18, 2009, 8:37pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/12 "2009-09-18T20:37:28Z")
This has been very enlightening. Thanks all.
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### Author:  [@Grumman](https://boards.straightdope.com/u/Grumman)
#### Post date: [September 18, 2009, 9:01pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/13 "2009-09-18T21:01:29Z")
For any starship that uses reactionless drives (i.e. most of them), your internal “gravity” force could probably be generated using the same technology as your propulsion force.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [September 18, 2009, 9:25pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/14 "2009-09-18T21:25:59Z")
> [@](#):
>
> Which episode(s) featured that?
It’s first hinted at in the second season, but not shown explicitly until “Razor”, the two-hour special that started season 4:
(minor spoiler)The Battlestar _Pegasus_ has those double landing bays on each side, and we see a Raptor turning over to land “upside-down” in one of the lower bays
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### Author:  [@Uosdwis\_R.Dewoh](https://boards.straightdope.com/u/Uosdwis_R.Dewoh)
#### Post date: [September 18, 2009, 9:34pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/15 "2009-09-18T21:34:31Z")
> [@flodnak](#):
>
> And in the novel 2010, the Leonov did not spin, and everyone floated around. When it was turned into a movie, somebody must have realized that this was going to be a pain in the rear to film, so the Leonov underwent a radical redesign to include a spinning section. The movie otherwise left me underwhelmed, but that little detail impressed me.
Speaking of the Leonov. The Babylon 5 earth [destroyer](http://www.babtech-onthe.net/ea/agamem1.jpg)and the [Leonov](http://www.cinespaceships.net/pic/leonov/leonov_3.jpg)look pretty similar.
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### Author:  [@Apollyon](https://boards.straightdope.com/u/Apollyon)
#### Post date: [September 18, 2009, 11:02pm UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/16 "2009-09-18T23:02:34Z")
> [@Mogle](#):
>
> It should be noted that those ‘artificial gravity generators’ do exist in the Babylon 5 universe, it’s just that Earth doesn’t have the technology.
Yes, didn’t the earliest earth ships have no gravity – the ships seen in flashbacks to the Earth-Minbari war with the crew strapped into seats – with the “modern” (B5 period) ones using spinning sections. (And then the new ones using bits of Minbari and Vorlon tech to get artificial gravity).
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### Author:  [@Superhal](https://boards.straightdope.com/u/Superhal)
#### Post date: [September 19, 2009, 1:01am UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/17 "2009-09-19T01:01:25Z")
Nobody mentioned magnetic shoes?
I forget which book it was in.
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### Author:  [@Lumpy](https://boards.straightdope.com/u/Lumpy)
#### Post date: [September 19, 2009, 2:03am UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/18 "2009-09-19T02:03:34Z")
> [@Superhal](#):
>
> Nobody mentioned magnetic shoes?
>
> I forget which book it was in.
In _2001_, the stewardesses of the inter-lunar transports wear velcro shoes to “walk” in zero-gravity. (Actually a very inefficient way to get about in zero-G).
Babylon 5 had a scene where Sheridan is outside the station for some reason and he’s standing on a platform with big letters saying “MAGNETIC SURFACE”.
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### Author:  [@Mr.Excellent](https://boards.straightdope.com/u/Mr.Excellent)
#### Post date: [September 19, 2009, 2:07am UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/19 "2009-09-19T02:07:18Z")
> [@CalMeacham](#):
>
> Centrifuges were used as artificial gravity in **2001, 2010,** and **Aliens**. In principle, you can get artificial gravity by constantly accelerating a 1G, but nobody’s done it in the movies AFAIK. Everybody else evidently uses some futuristic Special Relativistic Physics to make artificial gravity. Heck, they’re already exceeding the Speed of Light, why balk at Control of Gravity? ( **Forbidden Planet, Star Trek, Star Wars, Battlestar Galactica,…** )
Actually, might that be the explanation for gravity on the Galactica? I mean, she does appear to be under thrust in every scene …
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### Author:  [@Shawn1767](https://boards.straightdope.com/u/Shawn1767)
#### Post date: [September 19, 2009, 2:13am UTC](https://boards.straightdope.com/t/hows-gravity-supposed-to-work-on-a-sci-fi-spaceship/510626/20 "2009-09-19T02:13:16Z")
I don’t know if this is accurate, but I remember in my old Star Trek Technical Manual, there was a description of these circular devices in the floors that spun at high speed to somehow generate gravity. When the power went out on the ship, the slowly spun down so that the gravity would still work, but if power was out long enough, eventually there’d be no gravity on the ship as the devices finally came to a stop. Of course, the technology behind it was not explained.
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