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This is the next piece in my question-series, you guys have been absolutely awesome in your answers to the first question: How to solve the old 'gun on a spaceship' problem?

In this series, I try to find a number of questions bugging me while working out my current (awesome) project :)

All answers should be plausible, but not do not need to qualify as hard-sci-fi. I am aiming for Physics-Plus on Mohs Scale of Sci-Fi-Hardness (TV-Tropes link).

I am envisioning a system able to create the following effects:

  • General 1 G environment on space stations, space ships, orbital installations and so on.
  • The Gravity should not be generated by rotation (I am fairly familiar with these designs more rooted in reality)
  • If it can be done this 'gravity zone' should have a fairly constant feel to it, but a small 'gradient' is ok too.
  • The field should be fairly well defined in its dimensions.

In Units of handwavium (UHV*), which is the cheapest way of achieving this?

Further notes:

  • Form can follow function, so if a spherical field is most plausible, all spaceships can be spherical.
  • Weird events when two shielded entities are getting too near to each other are encouraged.
  • The use of kinetic weapons / missiles in ship-to-ship combat should still be possible.
  • The used solution should have the least possible implications. For Example: If I have complete control of gravity, I can do almost everything, right? So if there is any chance, keep it as low-tech as possible.

''Unit of Handwavium is defined by LSD/page (loss of suspension of disbelief / page)*

I am aware that some things are better left unexplained, but I strive for consistence. Thank you!

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    $\begingroup$ You really should warn people before using a TV Tropes link. Now I'm gonna be stuck there for hours. $\endgroup$ – DaaaahWhoosh Oct 12 '16 at 16:06
  • $\begingroup$ I feel you. Has happened to me. Such an awesome place. $\endgroup$ – openend Oct 12 '16 at 16:11
  • $\begingroup$ Problem here is that we do not know what gravity is and how the force comes to be. We only know how it manifests itself. Appart from constant acceleration we dont know other methods than "add mass" to do it. The add mass solution is offcourse poison to your ships moving, some ammount of handwavium needed, as many physics thought experiments rely on exotic material (which is a scientific word for handwavium, and unobtanium rolled into one). $\endgroup$ – joojaa Oct 13 '16 at 4:43
  • $\begingroup$ I'm tempted to suggest you don't need gravity, but that's kinda totally out of the scope here $\endgroup$ – Journeyman Geek Oct 13 '16 at 14:12
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    $\begingroup$ Wait, should it be measured using Imperial LSD/ or International LSD/page? $\endgroup$ – OnoSendai Oct 26 '16 at 16:49
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The real problem with what you are asking for is the hand wavium for artificial gravity involved super science as a minimum (how are you going to stabilize a neutronium sphere smaller than a neutron star, for example?) and insanely powerful engines to haul all that mass around. It gets worse if you try to wave your hands faster and use gravitons, or adjust the Higgs field in order to change the mass of the particles inside the field. If you can do that, why are you waving a Glock around?

A beam of polarized gravitons would selectively tear the ship apart, or you could set up destructive interference between your Higgs field generator and the one on the enemy ship. Destabilizing whatever holds the neutronium sphere or plate together effectively turns the enemy ship into a Nova bomb as the neutrons fly apart at near the speed of light....

The best advise I can give you is follow the lead of shows like Star Trek, Star Wars, Firefly, Guardians of the Galaxy and dozens of other space operas and have gravity floor plates as a "given" with no special discussion of how they work at all. If you want to disable the gravity field, then the hero (or villain) cuts the power cable or sends computer malware to bolix up the computer.

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    $\begingroup$ Pretty much this. Since you (@openend, the OP) have already thrown out rotational systems to simulate gravity, I would strongly recommend just accepting grav plating as a given. I haven't found any sci-fi that attempts to explain artificial gravity with any significant degree of real science that I haven't laughed at for being completely ridiculous. There's always the, "we got 1337 square meters of this stuff on loan from the Uberleetixx". $\endgroup$ – type_outcast Oct 12 '16 at 23:01
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    $\begingroup$ Just once, I'd like to see grav-plating that isn't somehow monodirectional, so people might walk on the ceiling of a corridor just as well as on the floor. Look at all that valuable floorspace you're wasting up there! You could effectively double your ship's living quarters! $\endgroup$ – undine_centimeter Oct 12 '16 at 23:17
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    $\begingroup$ @undine_centimeter Give everyone magnetic boots? $\endgroup$ – immibis Oct 13 '16 at 2:51
  • $\begingroup$ Neutronium would have insane tides too. $\endgroup$ – timuzhti Oct 13 '16 at 9:14
  • $\begingroup$ Looks like handwavium is the way to go here :) But I created the question to determine if this is the case. Thank you $\endgroup$ – openend Oct 13 '16 at 10:45
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Never turn the engines off.

Just make sure the ship is always accelerating "up" at a constant 1G. If you want to stop manoeuvring, just flip 180 degrees and burn the other way every now and then.

Cons: Requires infinite fuel, and you can't run away from anything quicker than 1G...

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    $\begingroup$ and you'd gradually approach relativistic speeds... $\endgroup$ – Journeyman Geek Oct 13 '16 at 14:04
  • $\begingroup$ Well, you can... "This is your captain, we need to get to any other position than our current one, and we need to get there fast, so hold on to something." $\endgroup$ – J_F_B_M Oct 19 '16 at 8:44
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Super low-tech version: wind generators. We already use it for poor man's antigravity:

enter image description here

Vertical wind tunnel simulated skydiving, Erik Charlton from Menlo Park, USA (Screaming Fast) CC BY 2.0, via Wikimedia Commons

Put generators on 'top', allow air flow via grid flooring:

enter image description here

Floor Metal Plate 02, Filter Forge, CC BY 2.0

I know, not really 'gravity', but hey - Nostromo wasn't any space Ferrari either. Advantage: UHV-free proposal.

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    $\begingroup$ Very creative! Working in a constant 60mph storm won't be too fun though... $\endgroup$ – Drgabble Oct 12 '16 at 21:04
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    $\begingroup$ @Drgabble 'WHAT?! WALKING A CONSTANT WHAT? CAN'T HEAR YOU!' $\endgroup$ – OnoSendai Oct 12 '16 at 21:19
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    $\begingroup$ I SAID (is knocked unconscious by turbulence around the door frame) $\endgroup$ – Drgabble Oct 12 '16 at 21:24
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    $\begingroup$ @Drgabble '...wait for it... wait for it... now!', squealed Admiral Ferdinand, to the delight of his host of invitees watching the video feed from his graviton-enabled suite, as the other economy-class passenger is tossed out of the balcony by the turbulent flow of the Wind Pass section. $\endgroup$ – OnoSendai Oct 12 '16 at 21:34
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    $\begingroup$ "Careful!" yelled Lt Gubbins, as Ensign "Sticky" had another cappuccino wrenched from his hands by a rogue gust. Sucked into the floor vents, the main floor fan short circuited in a shower of sparks, and the two men were left floating helplessly in a another cloud of boiling coffee. $\endgroup$ – Drgabble Oct 12 '16 at 21:50
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Well a simple, if dangerous, way of doing it is to use real gravity. For this, you need a good supply of small black holes, and a reliable way of controlling them. But if you have those, then your ships and stations are spheres, with their black hole at their centre, and a number of spherical decks around them. Because the black hole has much less mass than a planet, you'll have detectably different strength of gravity on different decks.

This will mean that you ships have very high mass, and accelerating them to high speeds is kind of difficult, but you win a few and loose a few. If you use this, may I suggest you don't explain to the reader how the gravity works, and leave them to puzzle it out. A reveal can come at the point when something goes wrong.

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  • $\begingroup$ You would just need an incredibly loud sound to generate said black holes. $\endgroup$ – CaptClockobob Oct 12 '16 at 17:13
  • $\begingroup$ One of the things with this is that the smaller a black hole, the more hawking radiation it emits, and it will also emit a lot of radiation if anything falls into it. $\endgroup$ – Lacklub Oct 12 '16 at 18:58
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    $\begingroup$ wouldn't a black hole that provided 1G of gravity weigh about as much as a planet? $\endgroup$ – Tezra Oct 12 '16 at 21:20
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    $\begingroup$ Next question from the author: My space station has suddenly disappeared; last I saw was a gamma ray flash. What happened? $\endgroup$ – void_ptr Oct 12 '16 at 22:04
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    $\begingroup$ @Tezra It'd be fairly massive, but since you could get much closer to its center, it would have less mass than a planet. However, there would be larger tidal forces. For example, if you wanted 1 G at a distance of about 1 km from the singularity, you'd only need about 0.02% the mass of Ceres. $\endgroup$ – Kyle Oct 12 '16 at 22:19
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Here's an idea, but it may use too much handwavium:

You could have a material which has radically different gravitational mass and inertial mass. For example, a material that has the inertial density of steel and the gravitational density of a white dwarf star. Then you need a decent amount (sphere with radius ~70 meters) to generate a gravitational field on the surface equal to earth's gravity. This would still give you a space craft that can accelerate fairly easily. You can tweak the gravitational density by a few orders of magnitude (neutron star density makes the required radius very small, and it's still hard to get enough to collapse into a black hole.)

For context: the inertial mass of an object is it's resistance to motion, while the gravitational mass is how much it affects and is affected by the force of gravity. It was a mystery why these numbers were identical for all materials in existence until Einstein proposed that it may be because the fabric of space is moving things, not that there is a force acting on some particles.

Beneficial consequence of this idea: this material can be exceedingly rare, occurring naturally, or be generated in small quantities (or large quantities) in a lab. You get some narrative flexibility using this as a plot point.

Unintended consequence: if you remember that all action has an equal and opposite reaction, you might realize that this material is very hard to handle because it is much more affected by the natural gravity of planets. In particular, the force that is pulling it to the planet is dependent on it's gravitational mass, and because it is less massive than expected for that much force it will accelerate much faster (by the same factor that it's gravitational mass is higher than it's inertial mass). This could mean that all of your spaceships are drifting out away from massive bodies, if they have artificial gravity.

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    $\begingroup$ I love that you question the basic assumptions of physics. We forget to do that sometimes. $\endgroup$ – Roman Oct 13 '16 at 11:44
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    $\begingroup$ I love this idea too :-P - How about needing some sort of gyroscopic handwavium of this material - makes travelling in a straight line pretty easy, but changing direction isn't nice: major changes would mean turning it off or slowing the gyro, and in combat it would pretty much have to be disabled for manoeuvres making zero-g important in some situations... The old "objects approaching the speed of light have infinite mass" idea ;-) $\endgroup$ – Rycochet Oct 13 '16 at 15:16
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Magnets!

Have the whole crew drink a regular dosage of liquid (non-toxic) metallic substance, and have the ship laced with powerful electro-magnets. Make sure anything else on the ship you want to be affected by gravity is metallic, or has something metal glued to it. Voila!

Pros: with superconducting electronics, should be almost energy free (assuming what goes up must come down and vice versa)

Cons: The metal must be evenly distributed around the body, or else you'll be pulled down by your stomach only (painful).

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    $\begingroup$ Replace skeletons with steel? Or just replace people with robots. $\endgroup$ – Daniel Darabos Oct 12 '16 at 22:46
  • $\begingroup$ You could just have magnetic body armour... $\endgroup$ – timuzhti Oct 13 '16 at 9:22
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    $\begingroup$ @Alpha3031 true, but then you would still feel many of the ill effects of zero g such as blood pooling in the head / heart issues etc $\endgroup$ – Drgabble Oct 13 '16 at 9:30
  • $\begingroup$ @Drgabble I guess it falls back down to a trade-off between more handwavium and less useful technology. Magnetic nanobots maybe. $\endgroup$ – timuzhti Oct 13 '16 at 9:37
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An alternative way to assist the suspension of disbelief, instead of giving a plausible explanation for why it works, is to instead describe in detail what it does. Describe all of its quirks and limitations.

This works well narratively because everyone on the ship will know in detail what it feels like when the gravity generator is on the fritz but few will actually understand the gravitomagnetic effect it uses to bend space-time around itself.

You can be creative and give it a lot of different problems.

For example, in Star Trek: Enterprise, the human engineers haven't figured out how to generate a completely uniform gravity field, and there's a small space in the Enterprise where it goes the wrong direction; in one room you can jump up and sit on the ceiling.

Other possibilities:

Does it taper off gradually outside the ship? If it changes a lot over a short distance, large delicate objects could be snapped in two by the relative difference in gravity at each end of the object when falling out of the field. This could be particularly impractical on a smaller ship with a smaller artificial gravity field.

Does it switch on instantly, dangerously throwing floating objects to the floor? Or does it take an annoyingly long time to spin up to full power?

Does the field itself have significant inertia? Does it have angular momentum like a massive gyroscope? It could take a lot of extra energy to accelerate or rotate the ship when the gravity generator is on. Maybe space tugboats and space marine boarding craft don't have gravity generators, to make them nimble enough to manoeuvre around other craft.

Is it physically huge, costly, or very energy intensive? It might not make practical or economic sense to include them on small vessels.

If it doesn't also propel the ship, and the gravity is pointing in one direction over most of the ship, then something on the ship has to be pushed up with a force equal to the force pushing everything else down. Possibly the generator itself. Strong structural beams would have to anchor the gravity generator to every section of the ship, or the ship would fall apart. To minimise bad leverage on these beams, a very large single generator ship might be shaped like a skyscraper with the generator near the bottom. Large vessels in other shapes would need either multiple gravity generators to distribute the load across the structure, or to have gravity pointing in opposite directions in different sections of the ship.

Does the gravity field's shape or strength change when the generator is rotated or accelerated? This could provide some light comedy with people spilling their coffee at one end of the ship when it turns around, or it could be a serious limitation to how fast a ship can manoeuvre with the gravity generator on without tearing itself apart.

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You could use gravitons like in star-trek. This would basically be using plausible particles that pass from one plate to another (works like magnetism, but with gravity!)

Your second option would be a sort of 'dimensional impaler'. Basically, gravity is generated by large masses distorting space-time around itself. So you could have an device that simulates this distortion to create gravity.

And the expensive option is Neutronium plates (make your ships weigh about as much as a planet)

EDIT: Found the word I was looking for for 'Neutron' plate.

EDIT2: I take back Neutronium as an answer as 'magic' would be less handwavium. Not only would using raw mass for gravity require something like 1.7916 × 10^17 kilograms (0.02% mass of Ceres based on comment here), But the massive gravity gradient from the lack of distance would make almost anything else more practical (especially just spinning the ship).

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  • $\begingroup$ Can you explain what a "neutron plate" is? $\endgroup$ – HDE 226868 Oct 12 '16 at 19:58
  • $\begingroup$ I don't remember exactly what it's called, but it's a theoretical 'alloy' that is basically made of just neutrons to achieve a substance that it absurdly dense and near indestructible. The Doomsday Machine from Star-Trek had a hull made of it but I can't seem to find what they called it. $\endgroup$ – Tezra Oct 12 '16 at 20:08
  • $\begingroup$ Neutronium only exists if there's gravity to keep it stable askamathematician.com/2010/09/… $\endgroup$ – Platypus Oct 12 '16 at 22:29
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I'm a physics layman so this may just be provably wrong.

If you could selectively over concentrate and somehow stabilize a subatomic particle that is responsible for mass maybe that could generate significant gravity in a small area at controllable rates.

Like maybe you have super dense "higgs-boson concentrated plating" that acts as gravity plating?

If you think it's neat you could have things in space falling toward the ships floor and require some sort of deflector device to push stuff away.

I think the more controlled the gravity the more you move towards some sort of high energy speculative thing on the level of controlled wormholes. At that point I think maybe you just hand wave the whole thing and use some gravity control field that isn't explained in a ton of detail.

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    $\begingroup$ The Higgs boson doesn't have anything to do with gravity, for the record. $\endgroup$ – HDE 226868 Oct 12 '16 at 16:22
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    $\begingroup$ ah, i figured since it was related to mass energy and more mass = more gravity maybe there was a relationship but like i said just a layman. $\endgroup$ – Tathel Oct 12 '16 at 16:26
  • $\begingroup$ You cannot say it has nothing to do with gravity. It has a mass, so it has a gravitational field and is affected by gravity. Also it is responsible for the rest mass of some particles. That rest mass also participates in gravitation. Is this incorrect? $\endgroup$ – Daniel Darabos Oct 12 '16 at 22:49
  • $\begingroup$ Gravitons may be the particles you are looking for: en.wikipedia.org/wiki/Graviton $\endgroup$ – Tim B Oct 19 '16 at 9:49

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