What

there are two thoughts on the 4th dimension

we live in the third dimension

time is the 4th

string theory goes up to ten or eleven.

but in some maths, the forth dimension just adds another direction to the three we can go

height, width, and depth

BUT

I like to combine the two theories.

both theories go with the XYZ (H, W, D)

but disagree on the 4th

you’re so smart

nah, I just think too much

My brain is just like flatlined

Reading that

to be fair, I should be asleep and probably not making much sense atm

math is a lot of fun. When you're not getting graded on it.

Yeah. In theory I get that but my brain definitely not wired for math at all. n-n

have you played zero escape? if not then you should

so... really the question is what kind of dimensions you have

if you have four space-like dimensions and one time-like dimension, then yeah, it'd fairly natural to regard time as the 5th (although i guess there's no reason you couldn't give it any other number you want to)

but you could just as well have 2 space-like dimensions and 2 time-like dimensions, theoretically

"three space-like dimensions and one time-like dimension" is mostly enforced by the anthropic principle, i.e. that matter and energy with the rules we know can only really exist in three space-like dimensions and one-time like dimension

like iirc there's theory strongly implying that you can't have complex dynamic structures (e.g. molecules) with two time-like dimensions

likewise, in anything but 3D-space, you can't have light propagation, and quantum mechanics gives elementary particles very different behaviors

Okay, I didn't know that last bit.

That's fascinating I wanna know more

Basically, in 3D space, Maxwell's equations say among other things that if you have a changing electric (or magnetic) field pointing in one axis and propagating in another, that field also generates a changing magnetic (or electric) field pointing in the axis perpendicular to both the first field and the axis of propagation

so if you have an electric field wiggling up and down, and you look at it from the north, you'll see it also generates an east-west oscillating magnetic field, which in turn makes an up-down electric field, etc

problem being, a cross product (the vector operation that shows up in Maxwell's equation, relating the field geometries to the field variation) doesn't... really work in 4D

trying to make a cross product of two vectors in 4D would have to be a surface rather than a vector, so light as a mutually-reinforcing oscillation between two coupled fields just doesn't really work

you'd need some very different physics to make anything at all light-like

I love learning stuff like this.

My original plan was to be a scientist, but in middle school I decided I wanted to be a writer instead.

i think i remember reading there's another order where you can construct a cross product again, like 7D or something? don't remember the details tho

ahaha relatable, it's hard to choose... orz