10 KiB
[D][WIP][BST][HF][HSF]Playing with extra spatial dimension anatomy and physics for fun and profit.
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Author: u/Nighzmarquls *
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URL: https://www.reddit.com/r/rational/comments/3xvfou/dwipbsthfhsfplaying_with_extra_spatial_dimension/
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Score: 9
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Created: 2015-12-22T19:55:53
Post:
So I'm toying with 'cosmic horror monsters as 4D animals' as a concept. But In doing so I'm starting to notice a pattern and I'd like a little bit of help catching any major lack of self consistency here.
For purposes of shorthand I will be using the 4th spatial dimension jargon of vim and vout. These are equivalent to up and down or left and right but for discussion space appears to need some weird extras in regards to this direction or else it's hard to determine why humans are not already 4D.
My posits for why humans and modern or at least early 20th century science has not noticed the 4th dimension is along the following:
Photons are flat in vim/vout and/or don't actually have an ability to move vim or vout compared to their emission source's orientation.
Thus matter which is not directly intersecting the plane of a given photon's emission plane is not effected by it.
Gravity also does not travel in vim/vout but maybe it does?
Electromagnetism and the strong force DO function across vim/vout or they are flat but 'spinning' in a manner that crosses vim/vout and other such.
My posit for a 4D animal then is it cannot use eyes reliably to see where it is going unless it has eyes lined up with the given planes of light.
I'm not 100% any of this would make sense for the stated goal of having humans that are mostly as we already exist, and also have a universe that is actually 4 spatial dimensions and can have relatively intuitive physical animals that do pretty intuitive shifts to momentum.
There are mechanisms needed to 'hold' us flat which I don't have a good sense of the best way to accomplish that yet.
Comments:
u/alexanderwales [+7] Time flies like an arrow (23 minutes later)
Emissions from a source follow the inverse-square law in three dimensions and the inverse-cube law in four dimensions.
If you were a two-dimensional creature with a two-dimensional emitter, you could use an emission detector to see that emissions followed the law of proportions; double the distance, receive half the power.
However, if you were a two-dimensional creature with a three-dimensional emitter, you could use an emission detector to see that emissions followed the inverse-square law; double the distance, receive one fourth the power.
If you were a two-dimensional creature with a four-dimensional emitter, you could use an emissions detector to see that emissions followed the inverse-cube law; double the distance, receive one eighth the power. And in fact, the same is true if you were a three-dimensional creature with a four-dimensional emitter.
So if gravity travels in vim/vout, then gravity follows the inverse-cube law. If electromagentism travels in vim/vout then we should see magnetic fields follow the inverse-cube law. If there were a higher spatial dimension that these forces acted on, we would know.
This doesn't really help you at all, just clarifying some of the difficulty involved.
u/Nighzmarquls [+1] (an hour later)
Ya that's why I surmised that essentially gravity and light at least are three dimensional emitters not 4 dimensional emitters.
In other words they are flattened in one of the four dimensions.
Electromagnetism and strong force seem to already be fairly limited in their range per power effect so I was considering there might be wiggle room at an earlier era of technology.
But it looks like the problem ultimately is that they ALSO need to be a 3-dimensional emitter as well.
Which is interesting but problematic.
u/ArgentStonecutter [+5] Emergency Mustelid Hologram (an hour later)
Electromagnetism and the strong force DO function across vim/vout or they are flat but 'spinning' in a manner that crosses vim/vout and other such.
Photons are the carriers of electromagnetic force.
Also, /u/alexanderwales comment on the effect on radiation. THis is actually a plot point n Greg Egan's novel Diaspora, which I encourage everyone in this group to read.
Really, what you need is a force that doesn't interact with normal matter at all. There's no reason this can't exist. You can throw in dark matter in as well, though 4th dimensional matter wouldn't simply be "dark Matter" since dark matter interacts gravitationally.
And, again, I recommend you read Diaspora before you go much further.
u/Nighzmarquls [+1] (an hour later)
already read diaspora a while ago, and flat land, and several other topics beside. The desire to VISUALLY illustrate a 4d in 3d critter is why I'm bothering to do the leg work for this.
Although I'm on reflection going towards all standard physics is 3D emission sheets that tend to normalize their angle/orientation on interaction with one another so the universe resembles a whole lot of sheets of 3D floating in 4D rarely interacting.
Gravity may or may not be less tightly constrained to any given sheet depending on if I care to get heavily into explaining dark matter or not.
Presumably the universe contained a lot less continuity in its total 3D plane in the past. Thus discontinuities of planes being threaded together oddly was a thing and is the original environment that our 4D animals evolved in the first place.
u/Chronophilia [+3] sci-fi ≠ futurology (5 hours later)
There are mechanisms needed to 'hold' us flat which I don't have a good sense of the best way to accomplish that yet.
Presumably, a pair of 4D forces that push matter into our hyperplane. Like if Flatlanders were just crawling along the ground in our 3D world, held down by gravity and held up by the normal force, but co-existing quite happily with 3D birds that can fly above and worms that can dig below.
The analogy with gravity suggests that 3D technology may be able to make small movements in the vim/vout direction, like a human can jump in the air and briefly defy gravity. But we can't phase through walls any more than a man can leap over a skyscraper.
4D creatures may be completely immune to these forces, or they may simply be able to fight them.
For purposes of shorthand I will be using the 4th spatial dimension jargon of vim and vout.
You may be interested in knowing that the book which popularised the Fourth Dimension called them ana and kata.
u/Nighzmarquls [+2] (a day later)
Ah, yes I recall those now... although apparently they did not stick as 'directional handles' for me as well as the vim-vout pairing did which I'm pretty sure I picked up from spaceland. mentioned elsewhere in the thread.
u/shadowstar731 [+2] (10 hours later)
Possibly a problem with conversation of energy? If energy is leaving our hyperplane through emissions vin/vout, why are we not seeing that?
I'm also curious if you have read Spaceland: A Novel of the Fourth Dimension, which is a take on the idea of us living in a secretly 4d world with 4d creatures (I wouldn't call that book a rational fic, though).
u/Nighzmarquls [+1] (a day later)
read that one too, and yeah not particularly rational.
u/Geminii27 [+2] (9 days later)
There are mechanisms needed to 'hold' us flat which I don't have a good sense of the best way to accomplish that yet.
I'm not sure that something preventing most movement in the 4th dimension would lend itself well to animated 4D structures such as animals. You could get away with 3D animals which could 'jump' up and down the hyperplanes, and sessile configurations similar to trees, but unless the animals themselves had some innate ability to annul the flattening effect of hyperphysics within their own skin, basic 4D maneuvers (such as rotating a joint anywhere except strictly within a 3D hyperplane, or pumping fluids through 4D networks) are going to be difficult to pull off.
Greg Egan's Quarantine speculates a little on creatures which extend beyond 3D space into fuzzy probability, and to whom the quantum-collapsing act of human observation is deadly; it essentially reduces them to a single 'slice', generally with lethal consequences. A 4D animal in a held-flat universe might well have a similar problem; it'd be equivalent to a human being sliced into ten thousand cross-sectional slides and then nothing being able to pass from one section to another (including nerve impulses, blood, parts of muscles or bones, neural signals...).
Effectively, you're going to need native (or artificial) 4D matter, which is not affected by the flattening, and 3D matter which is (perhaps all 3D matter has something like a vibrational frequency which attracts it to the matching hyperplane and holds it there, whereas 4D matter has no such frequency and therefore cannot get 'stuck' on individual planes). Add in something like quantum energy levels similar to electron shell levels, so that 3D matter can't be easily bumped from its vibrational plane. And maybe even throw in that it's the vim/vout uncertainty causing issues like the fixed speed of light. Hmm... increased energy of a particle in a hyperplane distributes more and more of that energy to vim/vout movement, causing the particle to have an effective top speed of c because the rest of the energy is going towards an uncontrolled orthogonal vibration, which shows up in the hyperplane as a heterodyning resonance effect called mass or gravity depending on how it's measured... too much mass in one place causes a particle to quantum-smear into the higher dimensions and show up as a black hole in the original plane?
u/Gaboncio [+2] (10 days later)
Maybe this will help you work on the subatomic physics you'd need to tackle for this to be actually believable.
But seriously, as has been pointed out, you'd need to expand the standard model by adding new 4D forces and their corresponding force-carriers. Changing literally anything about how the existing four forces act would make your universe irrecognizably different from our own. My suggestion would be to try to incorporate dark matter, but I can name multiple issues off the top of my head (such as "GRAVITY Y U NO INVERSE CUBE").