WARNING: SPOILERS BELOW
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I mean, I guess yeah. But at the same time you'd have to turn back 13 years, stop Peter from giving the secret away, and somehow keep hiding the Potters-- all without being seen by "yourself" or others. Even though it's noble, it's a LOT of work and as Dumbledore says, time travel is very dangerous.
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But remember with time travel, there's 2 of you in one place in the same time period, and the future self going back in time is not supposed to be seen by others. Remember how Hermione stressed to Harry "we cannot be seen."
Go back in time, knock out Harry's parents right after they give birth, abduct them and bring them back to the future. Then once Harry's finished his saving the world business throw him the best surprise party he's ever had with his parents as the guests of honour. They all get drunk on butterbeer. The end.
That would change all the present... if they weren't killed by voldemort then lily's love wouldn't have protected harry against him, harry would've died and voldemort would have succeded in ruling the magic world in the first place because he would have never been ripped of his physical form
They never said that the Time Turners couldn't turn the past on its head (rimshot), in fact I'm fairly certain Dumbledore said it could do exactly that; which is why he was especially careful with it and Hermione. If that isn't enough evidence, check the new installment, "The Cursed Child".
SPOILERS AHEAD SPOILERS AHEAD SPOILERS AHEAD SPOILERS AHEAD SPOILERS AHEAD
Essentially, Sirius Potter got a time turner and changed the past to try and save Cedric's life, which not only ended in failure (he still ended up winning), it resulted in Harry marrying Hermione instead of Ginny which caused Rose Potter to never exist and Hermione to become a Defense Against the Dark Arts Teacher. Going back in time to tamper with Cedric's life further results in Harry's death and for Voldemort to rise in power.
Buckbeak never died, they made a loop hole with time travel, so while they were going back to the castle and intercepted by sirius, the future them were saving buckbeak. Sadly, harry's parents weren't saved in the first place, so that can't be changed... time travel doesn't change the past, it makes it possible
except buckbeak never died. The kids saved him before he was killed. And sirius wasn't dead either. Almost but not dead before harry saved himself and sirius with his patronus. You can't go back and save the dead but you can prevent the person from dying. As for harrys parents they were already dead PLUS the circumstances were major different being they were killed by voldemort.
If someone stopped his parents from dying that night, nothing would have happened that lead up to the decision to keep his parents from dying and the events would have only taken place on a later date and more people would die to protect them, making the possibility to go back impossible. You haven't changed your future, you've just created a new one.
.
.
.
.
.
I mean, I guess yeah. But at the same time you'd have to turn back 13 years, stop Peter from giving the secret away, and somehow keep hiding the Potters-- all without being seen by "yourself" or others. Even though it's noble, it's a LOT of work and as Dumbledore says, time travel is very dangerous.
.
.
.
.
.
SPOILERS AHEAD SPOILERS AHEAD SPOILERS AHEAD SPOILERS AHEAD SPOILERS AHEAD
Essentially, Sirius Potter got a time turner and changed the past to try and save Cedric's life, which not only ended in failure (he still ended up winning), it resulted in Harry marrying Hermione instead of Ginny which caused Rose Potter to never exist and Hermione to become a Defense Against the Dark Arts Teacher. Going back in time to tamper with Cedric's life further results in Harry's death and for Voldemort to rise in power.