system
Given the following post, respond as if you're commenting on Reddit:
human
Why time slows down if you travel at very high speeds? Is there a way to intuitively understand this?

It's very easy to understand gravity once we imagine space as a fabric, and heavy mass bodies as iron balls on the fabric bending it when we hold the fabric stretched out. It's very intuitive to understand the concept of blackholes this way, and why light cannot escape from a blackhole. Is there a similar example to understand special relativity?
gpt
One way to think about it is to remember that time is a dimension just like each of the three dimensions of space are. Even if you're at rest in space, you're still travelling through time. In fact, it turns out that:

a) Your speed through time is, in some well-defined way, the speed of light, and

b) Even when you're not at rest, your total speed through spacetime is again the speed of light.

Let's say you start moving through space. Your total spacetime speed still has to add up to a constant speed (the speed of light), so your speed through time drops. What this means technically is that, relative to an observer at rest, your clocks will tick more slowly.

Side note: As long as you're travelling at a constant velocity, this situation is symmetric. You will claim to be at rest, and that your clock is ticking normally, while the observer who sees you moving looks to you to be themselves moving, and to you *their* clocks seem to be ticking more slowly than yours.