eastathenaeum
11 months ago
Well crap... I made two entries here and it appears the first one got flushed down the toilet.
asterion
11 months ago
It is probably a part of my antiquated processes but I always edit my website on my computer before uploading it to the web. Using that method, I always have a perfect copy of my website should something unfortunate happen with Neocities (or any web hosting service, for that matter).
daliwali
11 months ago
not antiquated, but the only way to roll. i run an http server locally which is necessary for modern javascript (es modules) to load correctly, and use my preferred editor (gnu emacs) locally. also nice to have a local copy of my entire webbed site which i upload from.
eastathenaeum
11 months ago
Good advice. Not sure if it would help in this situation, because I just copy and paste the sections on pages like this, so basically somehow I just edited over it. I normally back up monthly, because I don't want to lose progress for the monthly pages, but this was same day within hours of each other.
eastathenaeum
11 months ago
Probably a good thing though, because I know my blog page is already kind of negative. All the positive stuff I want to talk about ends up on pages, and this is the nerd rage portion of it. Mostly the highlight was how the movie Section 31 sucked.
eastathenaeum
11 months ago
Finished as much as I'm going to do for matrices by themselves in 2D Geometry. They were only necessary to include because vector space is needed to explain conic rotation, and matrices with vectors on a related note can represent the conic general formula. I figured what the hell.
eastathenaeum
12 months ago
Coding and minor fixes. Not really sure what to do with this page. The information is old.
xpaper
1 year ago
Currently the only rigorous notion of 4-dimensionality I feel I understand well is the Linear Algebra notion of a vector space with 4 linearly independent vectors. Everytime I try looking into tensors, I just get confused, so I'd be interested in seeing what you mean by "a metric tensor with a negative eigenvalue." I know what a metric and an eigenvalue is, at least.
eastathenaeum
1 year ago
After seeing enough of these, visualizing in enough different ways, and thinking about it for too long, 4D space becomes so easy to understand that it's kind of a no-brainer. Not going to lie though, it took me years.
eastathenaeum
1 year ago
The negative eigenvalue in time has everything to do with entropy in a positive direction, especially in particle interactions. Spacetime is dynamic, which means that it is tending eventually to a point of rest. This played a large role alongside the universe's expansion leading to the assumption of heat death, that time itself would eventually breakdown, no events, even though space would continue to expand forever.
eastathenaeum
1 year ago
Don't beat me up if I got any of that wrong, by the way. There's been loads of observations in the last few years alone, especially with JWST, that have been telling us that our existing cosmological models are definitely fundamentally flawed and in need of rewriting.
xpaper
1 year ago
To be honest I wouldn't know if you are right or wrong lol physics is by no means my area of expertise. I was hoping for more of a pure-math explanation. For me 4D or 5D or nD vector spaces already make sense (just add another coordinate), even if I don't know what they look like.
eastathenaeum
1 year ago
As far as purely mathematical, I don't know of any applications. I was trying to say in the intro while angrily shaking my fist that time has nothing to do with it. There's always one that's like "Time is the fourth!" All of these softwares are pure Euclidian space, because responsible adults made them. Lol
letslearntogether
1 year ago
@xpaper - It sounds like you already got the gist of it. Most of this software seems to treat the concept of "four dimensions" as simply an extra coordinate, let's call it w. Changing that w coordinate gives us another space, while changing x, y, or z changes our place within that particular space.
letslearntogether
1 year ago
In the context of Physics, a "scalar" is only a magnitude (e.g.: a speed given in miles per hour). A "vector" is a magnitude with direction (e.g.: 60MPH due North). Both are "tensors". A scalar is a "tensor of rank-0", a vector is a "tensor of rank-1", and so on.
letslearntogether
1 year ago
More specifically, tensors are objects that can be described as points on a "manifold". A manifold is a space that may have different "local" and "global" properties. A common example is the Earth. Locally, its surface seems like a flat plane, but globally, it is a sphere. This is a concept from Topology.
letslearntogether
1 year ago
The concept of tensors is not used as much when it comes to Linear Algebra. A rank-2 tensor can be described by a matrix, but tensors are not synonymous with matrices. In Physics, you might switch from using one branch of math to the other depending on what you are describing though. So, the term "four dimensions" is often referring to either one of two concepts when used in Physics:
letslearntogether
1 year ago
1. The use of four coordinates where x, y, z describe where something is in regular Euclidean space, and a coordinate t that describes when it is there. Simple and intuitive. But when dealing with extremes of speed, like in the case of Relativity Theory, we would use "Minkowski spacetime".
letslearntogether
1 year ago
2. In Minkowski spacetime, we still have the three axes of Euclidean space, but "time" is considered a fourth axis that objects travel along at the speed of light. This makes the speed of light constant for every observer and everything else is measured relative to that.
letslearntogether
1 year ago
Personally, I feel that a lot of seemingly complex math has been thrown at what are essentially simple relationships, so I understand eastathenaeum's displeasure with how the idea of "four dimensions" is often presented.
xpaper
1 year ago
I have varying levels of familiarity with everything mentioned here. However, I feel like I still don't have an answer to the question of how someone would go about determining eigenvalues for the "metric tensor of a dimension" and what those objects are in a mathematically rigorous sense. But when I look into it that's precisely the part that remains mystifying.
eastathenaeum
12 months ago
It sounds like the confusion lies in assuming that spacetime is an object residing within dimensions as opposed to the dimensions being a part of spacetime itself. Basically the metric tensors are functions that translate how space looks to us with what is actually going on and visa versa, a feature of projection for mapping in differential geometry.
eastathenaeum
12 months ago
I'm thinking about either changing or removing the wording now, because on all levels, peoples' minds are already made up for whether or not time exists. To me that's kind of a dumb argument, because how do you experience something for yourself and claim it doesn't exist? It's like saying emotions don't exist because they are just biological chemical reactions, when in reality that's an argument for how they exist.
letslearntogether
12 months ago
@eastathenaeum - As in teach professionally? You are too kind. No, I just love learning and sharing...While I cannot speak for xpaper, I think they were trying to grasp what "the negative eigenvalue of a metric tensor" means mathematically. In other words, how do we calculate that? Are we treating a metric tensor as a matrix and then finding its eigenvalue?
letslearntogether
12 months ago
If I had to take a guess, from your descriptions on the dynamic nature of spacetime, I have a feeling that you are using the inverse of the resultant eigenvector(s) to define "time"...as if spacetime itself is expanding at the speed of light, something like Einstein's cosmological constant...
letslearntogether
12 months ago
Don't quote me on that though. I could be entirely wrong. I'm just trying to understand exactly how you are looking at the situation. You obviously have a deep understanding of it.
letslearntogether
12 months ago
@xpaper - The concept of spacetime is such an interesting amalgam of Differential Geometry, Topology, and Linear Algebra that it can be a challenge to understand it. Some of the best videos to get a general idea of the Math behind it that I have seen are: https://m.youtube.com/playlist?list=PL__fY7tXwodmfntSAAyBDxZ4_eE3ZwbFE
letslearntogether
12 months ago
I usually approach the idea of "dimension" in terms of how many coordinates are needed to specify any location within a given space. So, a "1-dimensional line" only needs one coordinate to specify any point along it, a "2-dimensional plane" needs two coordinates to specify any location within it, and so on.
letslearntogether
12 months ago
In the same way that we might think of a "2-dimensional square" as a slice of a "3-dimensonal cube", we might think of a 3D cube as a slice of a "4-dimensional hypercube". People might trip over visualizing such a thing, but again, all we are really thinking about is how many coordinates. When it comes to applying this idea to Physics, well...
letslearntogether
12 months ago
To be honest, I think Einstein (and the theoretical physicists who followed him) go a little overboard with the Math sometimes, to the point of obscuring the actual physical phenomenon that they are describing...though I am not as harsh with my assessment of Relativity as Nikola Tesla. 😂
letslearntogether
12 months ago
One has to keep in mind that Einstein formulated his idea of spacetime when scientists were arguing over the constitution of the aether. So, I think Einstein was like, "Here guys, let's just use this mathematical model to describe light and gravity for now. We'll figure out the composition of the aether later." Unfortunately, it seems to have led to a lot of confusion.
eastathenaeum
12 months ago
No, my understanding sucks, but thank you for the vote of confidence. I've only taken physics for engineering & science majors 1 & 2 in college as well as some others completely unrelated to cosmology. I've read about it a lot in Wikipedia over the decades and kept up with hypothetical models trying to make breakthroughs, but that hardly constitutes as studying.
eastathenaeum
12 months ago
The eigenvalue is determined from a metric tensor matrix, which is the scalar equivalent to the eigenvector, so yes, that is correct. I'm kind of falling down a rabbit hole trying to find pure mathematical context, and everything I'm looking up leads back to physical interpretation. In relativity, negative eigenvalues are pretty much a given rather than a consequence. I never gave it any thought.
eastathenaeum
12 months ago
I just called a friend over this after numerous carefully worded searches. He has two degrees, one in math, and he told me there is no purely mathematical context, that all it would do is flip the field and that it is never used. Now my brain hurts because this doesn't sound at all like the context laid out in relativity. Lol
eastathenaeum
1 year ago
P.S. I LOVE reading hate mail. I've wanted to create a hate mail page since the inception of this site, but so far have not received any. Please find something about my site that you hate, and then wait till you're drunk and pissed off to message me. Thanks in advance.
bulltown
1 year ago
Hi Bill - I like what you did to the main page - looks good. And I just discovered you added bulltown to your neighbors page. I'll soon add you to the 'mutuals' sections of the main page and links page - really appreciate that! -joe
eastathenaeum
1 year ago
Thank you, it is mutually appreciated. Also, I have to mention that your appearance is iconic.
A pity that Blizzard never placed Diablo 3 onto Steam. Would you know why that is?
There doesn't seem to be an answer, like it was never considered. Kind of strange considering they still actively update it, at least with seasonal campaigns.
Learned code for double columns depending on device width as well as custom cursor
I didn't realize that there were any new games in the MediEvil franchise. That was a nostalgic game I remember well from my childhood (the original MediEvil) but I'll probably not bother with the reboot (already have so many other interesting things to play or to do). Anyway though, regarding Diablo 3, asterion, the reason is probably something to do with the royalty rates and/or the costs of re-release in AAA dev.
One thing people often doen't realize about AAA games is how huge their advertising costs are. I've looked at Blizzard budget reports before and I know that on at least one game they spent more than half their entire dev budget just on advertising alone. Re-releases of games influence the reputation of a studio or publisher and so if they don't get enough sales their reputation can be harmed.
Therefore, when a AAA company re-releases a game they may feel compelled to invest ad spend in it, but for older games which are also going to be subject to a steep platform royalty rates (such as on Steam, though big companies negotiate custom deals that are much better and not the blanket 30% that small companies get). I used to work in AAA about a decade ago, but only as a programmer not a manager. Just theories.
There was a rerelease of MediEvil 2 also, but I couldn't find a trailer. Going to be adding other, older games that are on a list, but I wanted to find newer ones first.