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So I've been browsing Worldbuilding for a while now and the answer to so many questions seems to be "No, gravity doesn't allow it".

Gravity (and the square-cube law, but as I understand the problem with that is also gravity) means we can't have believable dragons, giants (of any kind), large insects, flying whales. Even tall buildings and various sci-fi spaceship abilities are limited by gravity.

So I'm wondering is it possible to replace gravity with a similar force that keeps things attached to planets and makes things fall (orbits are a nice extra bonus but optional for the purpose of this question) and all the other things we expect from gravity, but that doesn't crush our giant creatures or make large flying animals impossible. Just lowering gravity isn't enough, that comes with its own different set of problems.

Obviously you can handwave this (and most stories and worlds must) and it's not something that would directly be mentioned in most cases but I'd like to know whether there is some other formula for gravity or another way to implement a similar force that allows fantasy worlds and creatures to exist without handwaving.

I understand this question may be impossible (or very difficult) to answer, but we have some very clever people on here so I'd be interested to see what they can come up with.

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  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$ – JDługosz Apr 21 '17 at 16:36
  • $\begingroup$ Sure, set your world in an 2D universe and the square cube law will no longer bother you. $\endgroup$ – Surprised Dog Nov 21 at 3:59
  • $\begingroup$ Pesky, annoying gravity, ruining WBuilding for everybody... Write to your elected moderator today - vote to cancel gravity! $\endgroup$ – Nahshon paz Nov 21 at 9:26
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Gravity (and the square-cube law, but as I understand the problem with that is also gravity) means we can't have believable dragons, giants (of any kind), large insects, flying whales. Even tall buildings and various sci-fi spaceship abilities are limited by gravity.

Actually, flying whales already fly in the lowest layer of earth's atmosphere, which is liquid. Having a liquid, breathable atmosphere could allow tall buildings, heavy flying animals and so on, without touching gravity, but compensating it by changing buoyancy. Or you can keep the atmosphere like it is, and invent some extra low density materials.

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  • $\begingroup$ Any fluid, technically. Heavy air would work just fine. $\endgroup$ – PyRulez Apr 21 '17 at 13:00
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    $\begingroup$ So...wth enough salt, water, and vodka we could live on the surface of a neutron star. Hmm. $\endgroup$ – Draco18s Apr 21 '17 at 15:57
  • $\begingroup$ What about pressure? Wouldn't things be crushed the further down they went if the atmosphere was all liquid? Nice idea though. $\endgroup$ – adaliabooks Apr 21 '17 at 16:16
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    $\begingroup$ I misread the last bit as "extra low density mammals", which provides an amusing alternative. $\endgroup$ – Mathily Apr 22 '17 at 5:00
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It's not really explained in numbers, but here is my idea:

Magnetic Fields only really exert high force on ferromagnetic substances, so why not make gravity only exert force on specific particles, that are present in everything and are "the new weight" of everything. That means, you could have objects with a lower concentration of these particles thus "making them lighter", even though you use the "same" base material (density is hard to determine, but it might look almost the same (except the effect of gravity on the material)).

Dragon blood and flesh might look the same as the human counterpart in my scenario, but it will be "lighter" while still having a flesh texture.

My way of working around it does impose new problems as weight and mass are relative to each other and the effect of the object's mass is often generated by gravity. All effects of mass would still need to be able to work the way they do in our world, although mass can not be influenced by gravity in my scenario.

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    $\begingroup$ I like this idea. It's got a certain logic to it without breaking too many other things. $\endgroup$ – adaliabooks Apr 21 '17 at 16:17
  • $\begingroup$ How would all the non gravitational particles be attracted into planetary systems during their formation in the first place? $\endgroup$ – Mołot Apr 24 '17 at 4:59
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    $\begingroup$ @Mołot I would say they bond with the gravitational attracted particles by some special force. $\endgroup$ – C.Fe. Apr 24 '17 at 6:30
  • $\begingroup$ Isn't this solution simplified by just living on a smaller planet that, by definition, exerts less gravitational force? $\endgroup$ – Azuaron Apr 24 '17 at 15:25
  • $\begingroup$ @Azuaron The advantage of not having just less gravity is that the environment could be exactly the same, but it still allows for some enourmous things or even something being able to hover. Having just less gravity makes it so that everything can just grow in size. $\endgroup$ – C.Fe. Apr 25 '17 at 14:14
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Don't change gravity, change the materials it acts upon.

Gravity is not actually the evil illuminatus depriving us of giant animals, machines and buildings, because gravity doesn't feature in the square-cube law at all; it's purely a geometric principle describing how doubling the linear size of an object squares its surface area and cubes its volume and hence (assuming constant density) cubes its mass. The symptoms of this that prevent our exciting creations are many and varied:

  • Doubling the thickness of a steel girder squares its tensile strength but cubes its weight, so there comes a point where larger buildings cannot be built strong enough to withstand the forces acting on them. Gravity is one such force, but winds, earthquakes and even solar heating would also take their toll.
  • Since insects oxygenate their bodies through direct gas diffusion from spiracles on the surface to a network of tracheae leading to internal organs, their maximum size is constrained by the rate of gas diffusion: doubling their size gives four times as many spiracles but eight times as many cells to nourish
  • The maximum height, speed and range of any flying object, be it dragon, bird, plane or rocket, is constrained by the amount of fuel it can carry. Doubling the size quadruples the object's air resistance and octuples its inertia, leading to poor handling and limited range even ignoring the effects of gravity.

In all these cases the problem is that increasing the size increases the beneficial quantity but increases the disadvantages faster, meaning that eventually you reach a limit point where further increasing the size makes the object less effective, not more. In order to truly escape the tyranny of gravity (and all those other forces), therefore, you must attack the square-cube law directly.

Fractals are geometric structures which have infinite depth of detail, and one of their most intriguing (and mind-twisting) properties is that they can have a non-integer dimension. That is to say, a line is a one-dimensional object, a square a two-dimensional object and a cube a three-dimensional object, but a Koch snowflake is a 1.26-dimensional object, despite looking superficially like an 'ordinary' snowflake at the macro scale. That is to say if you made a steel I-beam with a Koch-snowflake cross section and then doubled its size, you would increase its length by a factor of 2, its cross-sectional area (hence its tensile strength) by a factor of just 1.26, and its volume (hence its weight) by a factor of 2.54 (since the length dimension is not fractal). If you're trying to build a super-light airframe for a plane or zeppelin, such a length-weight ratio is a Big Deal. There are other fractal patterns with even lower dimension, such as the Gosper curve with $D \approx 1.13$, which would make an even better material cross section, or a three-dimensional version of the Koch snowflake with $D=2$ (rather than the normal 3).

What fractal geometries allow you to do is to make things superficially bigger without actually occupying all that extra volume and area. You can keep gravity exactly the same and it will act on 'normal' objects just like it does now, but you can add 'magical' objects and creatures on which normal gravity appears, superficially, to act differently.

Note that for this to work the structure of the object has to be actually fractal, not just the best approximation we can manage with ordinary materials, even down to the atomic scale. If you give up your subdividing when you get down to electrons and quarks, you've missed the point ;-)

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This is a little outlandish (and, for the record, no I am not actually a pastafarian), but might give you ideas regardless...

What is this "gravity" you speak of?

Everyone knows there is no such thing. The reason stuff falls is because the FSM's noodly appendages push down on all things, because, y'know, just floating off into space would be super-annoying. Who knows if He does this, in the same way, on all planets in all universes?

Point is, if you're willing to suspend a little disbelief for the sake of your story in order to get around the harsh mistress "gravity" (and if you have any sort of "magic", it's more or less given that you are willing), why not just go for it? Be creative! Your universe doesn't have to follow the laws of physics as we know them. Maybe it selectively ignores them, whether due to magic, supernatural beings, because reality is really a computer simulation, or whatever...

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