QUOTE (stonicus @ May 2 2007, 01:23 PM)

Ok, so extrapolate the rules of time travel for me from the last show. Without the rules of time travel, we have no idea what the significance of any of the actions shown in that episode are.
Since you asked so nicely:
I'll start by delineating the primary differences I believe exist between F_Hiro's original time line, as seen in the GN
String Theory, and what we saw Monday.
Time Line 1This is the one P_Hiro saw when he initially jumped 5 weeks into the future and first saw the explosion.
F_Hiro did not travel back in time to talk to Peter on the subway.
This means that Sylar really did kill Claire at homecoming, meaning he can now regenerate.
One thing leads to another.
Sylar is building to an explosion (most probably due to stealing Ted's power.)
F_Hiro (before losing Ando and getting all dark and brooding) kills Sylar.
Sylar gets better (Claire's ability, remember) and explodes anyway.
Nathan by a series of flukes gets elected and makes certain the public knows that Sylar is at fault.
Sylar kills several specials, including Candice.
Sylar kills and replaces Nathan, and institutes Operation: **** On Earth.
(We have no idea what gives Peter the scar- but without Claire's ability, it doesn't really matter.)
Time Line 2This is the one we saw in
5 Years Gone.
F_Hiro travels back and tells Peter to save Claire.
Peter interferes during the homecoming events, and stops Sylar from killing Claire.
Unfortunately, this exposes Peter to both Claire's ability and the entire Heinz 57 mix of Sylar's abilities.
One thing leads to another.
Peter is building to an explosion. (Cause unknown. It could be Ted's ability, but we've seen Peter try and explode without having been exposed to Ted, so there's no need for him in this theory.)
F_Hiro (before losing Ando and getting all dark and brooding) kills Peter.
Peter gets better (Claire's ability, remember) and explodes anyway.
Nathan by a series of flukes gets elected and makes certain the public believes that Sylar was at fault.
Sylar kills several specials, including Candice.
Sylar kills and replaces Nathan, and institutes Operation: **** On Earth.
The Gestapo find Claire and bring her to Nathan.
Sylar gets to kill her, finally, and take her ability.
(We still have no idea what caused Peter's scar. In this reality, it is likely a side effect of the sword and the explosion causing him to either be unable or unwilling to fully regenerate.)
Now and explanation of why (I believe) F_Hiro didn't notice the differences in the Time Line.
Primarily, Hiro's ability allows him to step outside of the normal Time-Space Continuum and move along the Time Stream until he desires to reenter.
When F_Hiro went back to the subway, he caused a ripple effect that minutely shifted the entire Time Stream into a new path. However, since this unraveled over the 5 years between the warning and F_Hiro's time, and F_Hiro was
outside the Time Stream during this ripple effect, the changes had no effect on him.