SoylentNews is people
SoylentNews
from the 4-dimensions-ought-to-be-enough-for-anybody dept.
Scientists have managed to constrain the possible number of dimensions of our universe to 3+1 (3 spatial and 1 time).
According to a new paper on Arxiv https://arxiv.org/abs/1801.08160
A recent merger of neutron stars that was observed in the visible spectrum, as well as with gravity waves, was used to determine that there are no extra dimensions for gravity to leak into. This reinforces our current models based on 3+1 to an extremely high degree of certainty and essentially rules out any theory that requires extra dimensions in order to function.
Quoting the paper:
The observation of GW170817 in both gravitational and electromagnetic waves provides a number of unique tests of general relativity. One question we can answer with this event is: Do large-wavelength gravitational waves and short-frequency photons experience the same number of spacetime dimensions? In models that include additional non-compact spacetime dimensions, as the gravitational waves propagate, they "leak" into the extra dimensions, leading to a reduction in the amplitude of the observed gravitational waves, and a commensurate systematic error in the inferred distance to the gravitational wave source....
The short of it was that there was absolutely no evidence for electromagnetism and gravity to be propagating through a different number of dimensions than the expected 3+1.
These are just some really cool and unexpected results; in my case I was a big supporter of brane theory until this result came out. Now, I don't know what to think. Gravity is too weak to make any sense at all. What do you think?
(Score: 1, Informative) by Anonymous Coward on Saturday October 06 2018, @03:49AM
I keep hoping that Miegakure [miegakure.com] will be released some day, but it looks like it'll release around the same time Star Citizen does. (i.e. never, but the page has been updated to indicate it's targeting Playstation 4 now.) The videos are fascinating, and I love its approach the problem of presenting 4 spatial dimensions without attempting to project everything at once.
I've played some other 4d games that do attempt to project everything at once, at least ones that support stereo pairs. Projecting from 4d to 2d loses too much information, so retaining depth allows the projection to only need 4d to 3d. I suppose VR is probably asking for a video game with 4 spatial dimensions since the depth information is baked into the platform.
It's easy to think about extra spatial dimensions logically. It's incredibly hard to try to wrap one's intuition around it. (Exception for the way Miegakure does it, which is very clever and also very simple.)
I've tried a few different games that display as wireframe that do a simple perspective projection with free rotation about all 4 axes. One maze game was especially irritating because I couldn't tell what was a corridor and what was a wall. There was a 4d chess game that simply displayed multiple boards using isomorphic projection: x-y, x-z, x-w, y-z, y-w, z-w planes iirc. Pieces themselves weren't models, just images indicating their positions on each plane within a 4-cubic grid. Very much like xboard.
Wikipedia has a list of four-dimensional games [wikipedia.org] for the brave.