I was having a look at Seeing the fifth dimension and I was thinking the following.

A dot is 0-dimensional entity. A dot "living" in an 1-dimensional world would be a moving dot along a pipe of some sort. The dot would perceive the dimension as time.

Again, a line in a 2D-world would again perceive the second dimension (y-axis) as time for travelling around the 2 dimensions.

The above 2 examples is our analogy of being 3-dimensional entities living in a 4D-world that we perceive time as the fourth dimension.

Are the above analogies right?

Mathematically, all the above are valid explanations, but am I thinking in the right way as far as Physics is concerned?

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    $\begingroup$ I would say all of those are wrong mathematical analogies. Spacial dimensions allow back and forth Time does not. Spacial dimensions can be interchanged with each other but not with time. In general, thinking of time as "one of the dimensions" is not a valid expression. $\endgroup$ – userLTK Feb 11 '17 at 4:18
  • $\begingroup$ Historically, the kind of thinking you're doing was formalized as Minkowski space, and also described as the block universe by the less mathematically-inclined. Henri Poincaré discussed the merits of this perspective in his essay, The Measure of Time (1898). $\endgroup$ – Nat Feb 11 '17 at 7:29
  • $\begingroup$ I'd add that this sort of thinking goes into a lot of modern theoretical models, e.g. string theory. Time reversibility occurs along world lines. $\endgroup$ – Nat Feb 11 '17 at 7:53
  • $\begingroup$ Thanks Nat for the resources, they are very helpful. Would you mind posting them as an answer, so that I can accept it? $\endgroup$ – Alexios Tsiaparas Feb 12 '17 at 9:44

Physics in concerned with space and time as perceived by observers. Space and time are ways for an observer used to precisely discribe what he sees. You have a clock, you can see things around you and measure angles between the rays of light (or other things) that hit you coming from what you look at. Physics does two things:

  1. It restricts the possible things you might see later given what you've been seeing until now. In optimal cases it even predicts exactly what you will see or probabilities for the possible things you might see.

  2. It tells you what other observers see when looking at the same thing as you, given where they are (where you see them) and how they move relative to you (how you see them move).

Anything besides this (spacetime, electric fields, temperature etc.) is just pictures helping your intuition guess the results above approximately, given approximate input. It is a common misconception that interpreting these structures has physical meaning. Don't get me wrong, intuition is extremely important both for using theories of physics and especialy for creating new ones. However you are asking "am I thinking the right way as far as Physics is concerned" when your thinking does nothing to help intuition with predicting the output of a theory built around spacetime. (If it does, I don't see it and you should explain. Find physical situations when your way of thinking suggests a wa, of guessinv what happens.)

As such, your question can't be answered. The analogies you provide may or may not be "good" for math, which is for the math forum to decide. Physics has nothing to say to that. (That is my opinion, which is the only thing you can get as an answer to that question, as opposed to facts.)


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