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Comment by orangegreen | Hacker News Reader

Time is the fourth dimension. Pretty simple.

This is akin to 2D beings saying time is the third dimension and being satisfied with the conclusion and happily living in their 2D world.

I always find it irksome when people call time the "fourth dimension." Time is not related to spatial dimensions, and claiming this shows a lack of understanding about the concept of higher spatial dimensions.

Time certainly isn't a fourth spatial dimension, but you can imagine if it was.

Time is very much a dimension inextricably related to the spatial dimensions (and vice versa) in reality so arguably one should find it irksome when the topic of a 4th spatial dimension isn't fully qualified instead of the other way around.

I think that can be forgiven in 1884 though :)

0th dimension: a point in space

1st dimension: a line in space

2nd dimension: a plane in space

3rd dimension: an object with mass (width, height and length), represented as a point in time

4th dimension: a time line, where the third dimension can travel on

5th dimension: a time plane, representing the events of infinite time lines.

6th dimension: third dimensional time space, which, honestly, gets kinda confusing, but I'm pretty sure it has something to do with the infinite possibilities of time planes. As in, time planes have time lines that actually happen, but 3d time space are what could happen? I'm not entirely sure.

And on and on. My visualization of dimensions is that it infinitely repeats itself based on point, line, and plane.

No, this is wrong/nonsense. I assume you got this from that one YouTube video? The one with the white background and animated black lines, claiming to explain 12 dimensions?

Learn basic linear algebra to get the idea of the dimension of vector space. Then maybe learn a bit about the box counting dimension or similar for fractals as another related notion (which allows non-integer values).

Speaking about dimensions without doing math is a mistake.

You seem nice.

I didn’t insult them.

I just told them to learn some things which are entirely within their capability to learn, so that they can think about the topic they were talking about, without thinking nonsense.

It shouldn’t take more than a couple hours (possibly under an hour to get the ideas I was referring to), and knowing basic linear algebra is good for a person.

If I was blunt, it is because I dislike misinformation, and highly value mathematics. Perhaps I’ve even warped my view of things in a way that makes me feel that someone understanding mathematics is a terminal moral good? Which, if so, is probably an error on my part.

You might want to look at Simplex to describe better and more rigorously. Simplex is the most basic structure to describe a space in n-dimension.

0-simplex: a point.

1-simplex: a segment (points and lines)

2-simplex: a rectangle (points, lines, and surfaces)

3-simplex: a tedrahedron (points, lines, surface and a 3D space that most of human can comprehend visually)

4-simplex: everything above and the whole combination of these element in algebra.

This is how mathematician and physicists solve problems. Time is a separate element in our equations that why we often talk space-time, not just space

https://en.wikipedia.org/wiki/Simplex

No, you can't extrapolate time dimensions like you can extrapolate spatial dimensions. This smells like "Imagining the 10th Dimension," which is hilariously bad if you haven't seen it.

The whole point of special/general relativity (at least the Minkowski approach to it, ie the approach that calls time a dimension) is that it the time dimension is related to the spatial dimensions. At non-relativistic speeds it seems unrelated, but for very fast-moving objects or particles the interplay between space and time becomes quite important, and for an object moving along a path the notions of time as-measured-by an external observer (roughly, ending coordinate in the time dimension minus the starting coordinate) and time as-measured-by the object (roughly, the Minkowski-length of a path in spacetime) become quite different things.

This just made me realize that the example given in the article of a 3D framework of strings interacting with a 2d plane would have its own speed limit since the fastest a point created by a string could move would be the case where the string was almost parallel to the plane. It would also stretch the moving point along its axis of movement approaching infinity the closer it got to being parallel. That thought experiment seems even more profound than it initially did. I wish I knew more physics.

Time is a fourth dimension.

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