## Gravity in 2D

Discussions about the possibility of consciousness, free will, spirits, deities, religions and so on, and how these might interact with time travel, the Big Bang, many worlds and so on.

### Gravity in 2D

Why when 2D models are discussed or explained, the direction of gravity is always with one of the two axis (making it into a "up, down, left, right" world)?
Why not along the 3D axis (making it a "north, south, west, east" world)?
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papernuke
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### Re: Gravity in 2D

because NSEW supposes no gravity. Up/down + forward/backward correctly suppose gravity and time respectively.
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wendy
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### Re: Gravity in 2D

Indeed, if you're going to have any relevant gravity at all, it has to be in the plane.

Flatland, for example, supposes a 2-D universe with no gravity.
pat
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### Re: Gravity in 2D

Having gravity perpendicular to a two dimensional universe would be just like having no gravity in that universe, since having the same amount of gravity everywhere would be equivalent to having no gravity. Without gravity there would be nothing to hold any kind of heavenly body together and there would be no stars, which would mean no objects larger than the 2d equivalents of hydrogen atoms.

papernuke! Are you starting to see the problem with your theory that gravity would be perpendicular to a two dimensional universe?
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anderscolingustafson
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### Re: Gravity in 2D

I can only say i wish everyone thinking about 2d universes would read "the Planiverse" in 1984, ( or google for exerpts) ( gravity, up down east / west) with , or instead of "the Flatland" 1884. ( plan view) Somehow, although it was big when it came out with Martin Gardner review in Scientific American, is in reprint, gets stellar reviews, everytime I see a reference to 2d existence or perception, (which is necessary for both quantum theory and relativity , which rely on observers, to have any meaning), its always "The Flatland". Come on, a square with one eye with no legs can can talk? goes to show that good science and good fiction together are rarely done..and more rarely, finding the success deserved.

And The Planiverse is good fiction, even with a Sufi mystics allegory, unless the neat diagrams ( no equations, but there are NAND gates) and logical consistency turns people off. Or the technical thoroughness.. it may be in fact over- imagined, or in accurately imagined. I know because I have a simulator, which really helps to test out models and iteratively design stuff for a 2d universe with any parameters that work well. With a thought experiment, you usually get to only one iteration , really.

The 2d world simulator i made at great personal expense is based on box2d which is real-time, meant for games, but with adjustable timesteps, I think as accurate an integrator as you would want for such a hypothetical universe. I've added are approximations of wind and water with waves, and I chose to use earth -like parameters and units and scales to make it familiar. For example, sound, weakens 1/r squared in my sim, and air friction/ 1 velocity squared, so that it would be more representable in a viewport, kind of like a log graph...The camera can pan an zoom , but that best to keep it to a minimum. However, as dispersive waves and flux goes, its a triangle, so the strength would be 1 / R, like gravity. But, when inventing a universe we can choose the size of the atom relative to the creature, the surface or edge detail. Many physical constants could indeed provide such an earth- like or 3d +time experience. When asked about this new theory that we are all holograms , and that the universe is 2d , even Steven Hawking said he didn't believe 2d life could exist. Because, he didn't apparently read about the 2d creatures and the zipper organs which make eating and digestion possible for them, without them falling in two halves because of having an opening on both ends.. the zipper can keep the creature together.

I read that sounds wound have a tail extending forever, if sound disperses 1/r. but Surely sound and gravity could weaken by approaching the quanta, or by changing to heat , being absorbed , deflected into space or some other. Anyways i play the game and it feels like a liveable life. I would love to see if the steam engine in the planiverse book works but now don't have the time. The planet is barren, featureless,flat..
Because things cannot buckle, i don't see any reason why cities with tall buildings extending high into the cloud would be impossible, and that everything must be underground . I make them, they stand. The winds are strong yet are so are the materials, they must rip by pulling the bonds directly apart. Winds are strong enough to allow you to survive high falls by spreading out, but your mass scales to the HxW while bone strength scales to the width. Same..as for us, with L x W x H(mass)/LxW (bone) mobility goes with 1/H... So life can find a convenient scale or two," life finds a way" , as in "Jurassic Park". And for anyone who was read the Planiverse, jumping over someone is nicer than walking on them. If anyone on this forum wants to experiment with the work in progress, its at http://www.puppetarmyfaction.com its free , to play the 4 levels, but i use tokens to track the newest features. If someone likes to design 2d devices,like I do, i can use some mechanisms, i rely on batteries, compressed air too much..
damian.hallbauer
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### Re: Gravity in 2D

damian.hallbauer wrote: he didn't apparently read about the 2d creatures and the zipper organs which make eating and digestion possible for them, without them falling in two halves because of having an opening on both ends.. the zipper can keep the creature together.

Oh that's clever! I was pretty sure there was a way, but that is an especially nice solution.
PatrickPowers
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### Re: Gravity in 2D

I read the planiverse. It's a more convincing story than Abbot's adventures in flatland, in that the story and events are much more realistic.
The dream you dream alone is only a dream
the dream we dream together is reality.

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wendy
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### Re: Gravity in 2D

wendy wrote:I read the planiverse. It's a more convincing story than Abbot's adventures in flatland, in that the story and events are much more realistic.

Thanks for the Plainiverse ref. Very cool! Their language is Maltese Arabic.
PatrickPowers
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