system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] What happened to the Harry and Hermione in the original timeline prior to using the time turner (where, presumably, Sirius Black had been caught)?
gpt
There is no "original timeline", the Time Turner operates on stable time loop principles. You go back in time and do what you've already done, even if you weren't aware of it before you did. Hermione mentions that it's impossible to actually change the past, and trying to never goes well, which is why it's so important not to run into your past self.