system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The concept of Dimensions. How do we know there are 12? How do we know which one is which specifically?

I know the first 3, (width, height, depth) and if I heard correctly the 4th is time. But yesterday this topic came up in conversations and to my suprise there is 12. But my friend couldn't tell me what they do either.
gpt
>How do we know there are 12?

We don't know whether there are 12, or any more than 4. Current conventional physics only uses 4 dimension (3 space + 1 time). The 12 dimensions you hear from are a prediction (or rather: a requirement) of certain speculative theories in physics like string theory. String theory has not been proven to be correct yet.

>How do we know which one is which specifically?

In the world of string theory, the other extra dimensions are very very small. They are nothing like the regular dimensions that we are familiar with. You'd have to zoom in to around the Planck length (10^(-35)m) to see them.