The explanation still kinda sucks. I like this one: The easiest way to understand the relationship between time and space is repeat the thought experiment with

The explanation still kinda sucks. I like this one: The easiest way to understand the relationship between time and space is repeat the thought experiment with the void, but assume that there is no consciousness there (i.e nothing running that can sense time passing). Now imagine the only action you can take is to fire particles (say photons) in a given direction. In a void, that action is meaningless - the particle fires and never comes back. No information exists. Now imagine there is a mirror somewhere in space. A particle fires, and then comes back. And maybe interacts with another particle. But still, this is generally meaningless and you cant derive any measurable thing from it, but you have a piece of information - particle comes back. Imagine there are 2 mirrors in different directions. What you do is you set up 2 identical devices. Each one fires a particle, and when the particle comes back, it triggers a certain color ball to fall down a common shared tube, and then the particle gets fired again. So with 2 mirrors, you get a sequence in the tube that looks something like blue, blue, blue, green, blue, blue, blue, green. Now you can make a measure of distance. You take the "blue" mirror as your unit, and say green mirror is 2 away. You have also in fact created a clock. The tube contains information on how many cycles have passed - i.e in order to say that mirror is x away, you need to have counted x blue balls before that respective ball shows up. So you can see how distance and time is intimately intertwined. To measure distance, you have to necessarily have something that measures time. Now lets say that the "green" mirror starts moving away from you, at a slow speed (i.e your particles are much faster. You start to see 3 balls in sequence, then 4, then 5, and so on. By comparing the difference in the subsequent position of the green balls, you can measure speed. What happens if the speed of the mirror is 99% of the particle speed? The particle takes its sweet time getting there, and sweet time coming back. Even if you fire the particle as the green mirror is close to the particle emitter, its going to result in a measurement of a very large distance. This is the relativistic effect where the space behind something moving fast increases. This whole experiment demonstrates that what we consider space is precisely defined by measurements, and relativistic effects alter these measurements, which alters our perception of space. You can do similar thought experiments to understand why space in front of you seems to shrink, why time dilation becomes a thing, and so on.