@Wryte: It could still be caused by Pinkie's mane, just in a different fashion. The reasons I don't get your theory is that
1. it doesn't explain how the loop forms and averts the disaster; it starts with the loop already there, and then explains how deviating from it would
cause the disaster. But it isn't a scenario where the disaster occurs in the original timeline
2. it doesn't explain why Twilight would inexplicably deviate from the loop by not cutting Pinkie's hair when all the other factors are the same. It's just saying "if the loop wasn't really a loop, the universe would end", which is true, but the idea is that creating the loop averts the disaster, not that the disaster is caused by deviating from the established loop.
Basically the issue is this:
The original timeline is that in which the time loop is stable.
There's no reason for the loop to exist at all in the original timeline. Or if it's entirely self-sustaining, then the disaster
cannot happen because there's no cause for it in the loop.
What I'm getting from the tweet is that the original timeline is the one in which the disaster occurred, Twilight started the loop (saving the timeline) but sending the message to herself, resulting in the cutting of Pinkie's hair.
For the record, I'm not taking this seriously at all, it's just fun to talk about.
edited 6th Jan '13 7:32:07 PM by JapaneseTeeth