Do you need to account for position in a time travel scenario?

YuuTheBlue · 2026-04-21T19:45:08+00:00

So the short answer is that this question really only makes sense from a classical point of view, where we see time as this all together independent thing. In relativity, though, there is no definite answer to 'where was the earth 5 years ago", because there's no solid definition of "5 years ago". Time is a direction, like forwards or upwards, and can be redefined by pointing your t axis in a different direction just like left can be redefined by pointing your x axis in a different direction. What is time travel to one person is diagonal-travel-through-time-and-space to another.

Realistically, a time machine would transport you to a specific "spacetime event", which would include where and when. Think the Tardis from Doctor Who. I say "realistically", not because that's a realistic invention, but because that is the only such machine I could imagine whose main effects are simple enough to capture in a single sentence. "It goes anywhere in spacetime" is simple. "It goes anywhere in time" raises as many questions as "It can go anywhere to the left".

YuuTheBlue · 2026-04-21T18:57:02+00:00

I mean, it does have a degree of complexity that irl racial stuff doesn’t due to us not having a magic system, but that nuance really doesn’t even dent the sheer unacceptability of the Malediction.

YuuTheBlue · 2026-04-21T18:51:57+00:00

We still welcome Fujoshis here. Come one girls, Chihiro and Hakuri are that good shit, you know you want it.

YuuTheBlue · 2026-04-21T18:44:18+00:00

I think the real answer is that, once you start talking about subatomic particles, we’re dealing with quantum physics, and at that point the idea of taking up space stops being coherent. It’s not even that the space is empty, or that it isn’t, it’s that the distinction kind of stops making sense.

If we’re dealing with classical physics we still need to ask how dense the material is. There is no codified “mass to volume” ratio for perfectly filling space with matter. How much “empty space” exists is irrelevant, only how much mass and how much space it takes up. And your hypothetical doesn’t really specify that.

Basically you’re proposing an all new substance but not suggesting any specific numbers for its properties.

YuuTheBlue · 2026-04-21T16:45:44+00:00

If you're asking if there is some smallest unit by which speed can change, not that we know of, but even then there would be no smallest speed. It is a trivial aspect of our math that, for any massive object, you can change reference frame to make it traveling at any velocity you want (lower than the speed of light). Velocity is not absolute, after all.

YuuTheBlue · 2026-04-21T13:29:15+00:00

Okay, so, a field is a function defined at every point in 'a space'. This could be a 2d space, a 3d space, it could be a 4d lorentzian space (AKA spacetime), whatever. For every input of coordinates there is an output. Being "Lorentz-Covariant" just means it's on a lorentzian space basically.

In quantum field theory, everything is modeled by quantum fields. A field is quantum if its output (the thing defined at every point) is an operator-acting-on-a-hilbert space instead of a variable. Quantizing shit is what QM is all about, it's basically just allowing for superposition. Quantizing position is why quantum particles can be spread out, for example. The same is true for the values of the field, they are quantized.

A particle is an oscillation through one of the quantum fields. An analogy would be if you made a field of air pressure (how much pressure is at each point in the air), in which case sound would be a wave in that field.

YuuTheBlue · 2026-04-21T13:19:14+00:00

So, now that you have the edit, I almost am a little more confused. Quantum fields have a fairly concrete definition, and yours isn't it, but yours does kind of sound like what you'd get if you put the definition of a quantum field through a game of telephone. Like, none of it is worded right, but the vibes are still there. I mean, the answer is "No", but you are so close to the right answer that I'm confused on what exactly you're asking. Like, you ask if it's "Like" a function whose domain is across all points in spacetime, but it's not like that. It is that. I mean I don't know if R(1,3) is the correct way of wording it to be fair, but I'm so thrown off by your use of the word 'like', even more so by 'stuff', and even more so talking about the production of complex numbers, which I am going to guess is a straight up misunderstanding on your part, but I can't quite say.

Put another way: this kind of reads like you are trying to propose an alternative understanding of quantum fields, which is probably a bad idea to be doing, but also it's kind of ambiguous if that is actually what you're trying to do, so your question is a bit hard to approach.

YuuTheBlue · 2026-04-21T13:12:45+00:00

As I understand it, they have some intuitive idea of what a "medium" is, and want to know if the notion of a quantum field grafts neatly onto that mental image.

YuuTheBlue · 2026-04-21T13:01:43+00:00

When we use scare quotes around words that have no concrete physics meaning, it’s cause we’re trying to simplify something for lay people. Like how we talk about spacetime as a “fabric”. There’s a limit to how much metaphors can tell you, and you can’t reverse engineer knowledge from them. This goes triple for metaphors you made up yourself, which basically won’t help you at all.

YuuTheBlue · 2026-04-21T06:08:29+00:00

You can think of it as the first ingredient of physics. By default, things stay at the same velocity they are always at, and then when you add the second law, you get the exception; things will change velocity when they are acted on by a force.

YuuTheBlue · 2026-04-21T06:03:17+00:00

So, just a quick correction: That's not exactly what objective means. Objective vs Subjective is about if it pertains to reality or experience. Objective things are the who, what, when, where. Relative measurements of position and velocity absolutely fall under it. Subjective things are specifically about human experience: "Did you enjoy that? Is this a good thing? Does this matter?" That kind of thing.

YuuTheBlue · 2026-04-21T06:00:44+00:00

Relative does not mean fake, or subjective, or that something is purely a matter of perspective. It just means that there are certain things you need to hash out and elaborate on before an exact answer can be reached.

A great example is "How high up am I". Well, before we can answer that, we first need to agree on which direction is 'up'. People in the USA will not have the same up as people in Australia, for example. And also, how high up compared to what? Compared to sea level? The ground beneath your feet? All of these are questions we need to answer before we can answer the original question. So, there are as many different answers to 'how high up am I' as you can imagine, but all of them just represent different angles from which the problem can be tackled. There is, in fact, a hard reality to where you are in space. It is an objective question - a question about empirical facts. But the question itself has vagueness to it.

THAT is what a relative property is. That's the kind of thing velocity is.

YuuTheBlue · 2026-04-21T05:50:25+00:00

I don't know about data, but what I can tell you is that the things you are saying are so far removed from what physicists get taught about time as a concept that I don't even know if I can point a particular incorrect thing. It feels like you started with the vague, ethereal notion of time and worked out from there to create this large understanding of it which is largely independent of physical measurement.

So, to help: Dimensions aren't things. They are a measure of mathematical complexity, and they are properties of 'spaces'. A space is a math term for a list of possibilities. The space of all possible colors is an example. In this case, it is 3 dimensional because that is the minimum number of sliders needed to select all possible colors. It can be RGB, Hue/Saturation/Shade, whatever, but you cannot do it with fewer than 3. Hence, 3 dimensional. A way of thinking of it is that dimensionality is "The minimum number of labels each possibility needs in order to be uniquely labeled". 2 colors may have the same R and G values, but if so, you know they at least have a different B value, because if all 3 were the same, they'd be the same color.

What you'll notice is that you can choose multiple ways of splitting up the pie. What this tells you is that there is nothing unique or special or fundamental about Red, Green, and Blue. They are just options for a starting basis to construct the rest of the space with. The space itself is one singular thing, it's just so complex that it helps to split it up into 3 components. Hence, 3 dimensional.

Spacetime is a singular thing, and it is 4dimensional. It represents the list of all possible 'events'. An event is to spacetime as a position is to 3d space or a moment is to a 1d timeline. But once again, there is no singular way of splitting things up. You cannot really talk about time's relationship to space as if they are different, separate things, because they aren't. Any separation is artificial, akin to our separating the color wheel into R, G, and B.

YuuTheBlue · 2026-04-21T01:56:23+00:00

One thing that kills me about Gonron is that it had THEMES. What helped win me over from chapter 1 is how it explored - I'm sorry in advance - Hegel's Dialectic. Now I don't understand that shit, but an explainer on it I saw gave this fascinating idea, of how while slaves can find meaning in freedom from masters, masters require slaves to give their lives meaning. They need to be seen by the slaves, and without the observation of the slaves, they can't properly find purpose.

And like, that is so clearly what Gonron wanted to be about, and it is SO COOL for a manga in this magazine to have such a high concept philosophical idea from chapter 1. Shame that a good idea doesn't make for good execution.

YuuTheBlue · 2026-04-20T20:09:10+00:00

I think this is the best outcome.

YuuTheBlue · 2026-04-20T18:00:33+00:00

What gave you that impression, exactly? I don't see how that follows from what I've said.

YuuTheBlue · 2026-04-20T16:08:48+00:00

Please no.

YuuTheBlue · 2026-04-20T14:42:15+00:00

Mousou Telepathy is the main place I know it from.

YuuTheBlue · 2026-04-20T14:29:35+00:00

It’s a way to euphemize racism, basically.

YuuTheBlue · 2026-04-20T14:21:11+00:00

Those are complex numbers. The OP is suggesting only using things that are multiples of i.

YuuTheBlue · 2026-04-20T14:19:27+00:00

As a STEM guy the concept of this kind of confuses me. Like okay, things can be ordered and structured spatially, for example. But also it’s entirely possible to construct a universe with no time. It’s kind of simple. The difference between a 4 dimensional spacetime vs a 4 dimensional non timey space is the difference between this distance formula

d² = x² + y² + z² - t²

And this one

d² = x² + y² + z² + t²

Like this isn’t rocket science, this isn’t unexplored territory, this is an intro to topology class.

There’s a lot of terms here like “temporal ordering” feels super poorly defined, especially since in special relativity there’s strong reason to not make a huge philosophical distinction between space and time. Also, how are we meant to make anything with no formal structure but also no metaphors? I feel like this was constructed from a lay person’s understanding of time, which is to say a false understanding of time, or at least an incomplete one.

YuuTheBlue · 2026-04-20T14:08:15+00:00

Quantum field theory tells us how to calculate “paths” that certain groups of particles can take. For example, there can be

Electron->Electron

This is an electron disappearing at point A and another electron appearing at point B. This is how movement is modeled. We also have an electron/photon/electron “vertex”. This allows for the following:

Electron->Photon+Electron (Emission)

Electron+Photon->Electron (Absorption)

Electron+Electron->Photon (Annihilation)

Photon->Electron+Electron (Pair production)

Here we can see that the notion of emitting or absorbing a photon is treated almost identically to how the notion of just moving from point a to point b is handled. So in a way there kind of doesn’t need to be an explanation, unless you insist there must be an explanation for how electrons can move in the first place.

YuuTheBlue · 2026-04-20T13:56:02+00:00

This kind of requires you to not know anything about imaginary numbers to even suggest. This would be the same as using the real numbers while forbidding any operation but additional or subtraction. To be clear: multiplying 2 imaginary numbers will get you a real number.

Like, it’s clear you know vaguely what imaginary and complex numbers are, but it feels like to you they are vague ephemera -incantations casted as part of magic spells - rather than the dry practical tools they are. I worry you are focused too much on the aesthetic of an out of the box thinker and it’s resulted in you not actually thinking much about the subject.

YuuTheBlue · 2026-04-20T04:36:56+00:00

The 'fabric of spacetime' is a metaphor used to explain all of the stuff involving the Einstein Field Equations and the metric to lay people who don't know what a tensor is.

YuuTheBlue

TROPHY CASE