[color=#000000:post_uid0]Don't think so quickly, I can't keep up with it. ;)

So you're saying that's where time stops? That sounds reasonable, in a matter of logic anyway. It makes me wonder, how did time start?[/color:post_uid0]

[color=#000000:post_uid0]I'm not 'saying' anything. I'm just speculating. ;)

[quote:post_uid0]I guess so, but I don't like doc's theory. It implies that if you could ever travel through time, you still better not (and that's a major understatement) because if anything goes wrong, all of mankind would never have existed. It's pretty pessimistic.[/quote:post_uid0]

This is why time travel movies/episodes are full of paradoxes. If they couldn't do anything that would cause a paradox, there would be no good movie/episode.

However, has anyone read Harry Potter and the Prisoner of Azkaban? In that book, Harry and Hermiony's time travel has only one paradox. A predestination paradox, because Harry saves his past self's life. Other than that, the story is sound.[/color:post_uid0]

[color=#000000:post_uid0][quote:post_uid0="Michiel"]However, has anyone read Harry Potter and the Prisoner of Azkaban? In that book, Harry and Hermiony's time travel has only one paradox. A predestination paradox, because Harry saves his past self's life. Other than that, the story is sound.[/quote:post_uid0]
That's not a paradox, is it? :S Obviously, Harry saved his other self's life all along. Otherwise, he wouldn't have lived long enough to go back and save himself.

So (tracing the timeline of events) Harry's life is threatened, but then his older self comes along and saves him, then he grows older and eventually goes back in time to save himself.[/color:post_uid0]

[color=#000000:post_uid0]Exactly, but what set those events in motion? Harry should just have died, after which he couldn't grow older to save himself. The fact that this didn't occur, indicates a predestination paradox.

Another predestination paradox, according to 7of9, is the movie "First Contact". The borg disrupt first contact on earth, which leads the starship Enterprise (with Picard) to help Cograine with his warp-flight. So, the federation thanks its existance to the borg.

There's also a joke about predestination paradoxes made by doctor Bashir in Trials and Tribble-ulations. :)[/color:post_uid0]

[color=#000000:post_uid0][quote:post_uid0]Another predestination paradox, according to 7of9, is the movie "First Contact". The borg disrupt first contact on earth, which leads the starship Enterprise (with Picard) to help Cograine with his warp-flight. So, the federation thanks its existance to the borg.[/quote:post_uid0]

Correction, this is called the 'Pogo-paradox', the causality loop in which interference to prevent an event actually triggers the same event. I just assumed it was a predestination paradox.[/color:post_uid0]

[color=#000000:post_uid0][quote:post_uid0="Michiel"]Exactly, but what set those events in motion? Harry should just have died, after which he couldn't grow older to save himself. The fact that this didn't occur, indicates a predestination paradox.[/quote:post_uid0]
No, he shouldn't have. I can't explain very confidently, because I don't know whether his younger self was aware of the time travel involved or even knew he was in danger, but it's no more paradoxical than if one non-time-travelling person were to warn another ordinary person away from a rickety bridge that would have plunged into a ravine had anybody stepped onto it.

And then there's always non-causal physics... :O :crying: :dead: Â Â Â Â Â ;)[/color:post_uid0]

[color=#000000:post_uid0][quote:post_uid0]Correction, this is called the 'Pogo-paradox', the causality loop in which interference to prevent an event actually triggers the same event. I just assumed it was a predestination paradox. [/quote:post_uid0]
I'm not exactly sure what you mean, but I think the same could have happened with Harry Potter. Or maybe not the same. What if he was originally saved by someone else, but, because he travelled back, somehow he wasn't, so he had to do it himself. He would have disrupted the timeline, by actually getting his younger self killed, but he corrected it, by saving himself, so that it all works out anyway.[/color:post_uid0]

[color=#000000:post_uid0]No, that doesn't sound right. I found a small summary of the book, here's the part I mean:

[quote:post_uid0]They are on there way back to Hogwarts and suddenly Lupin gets in front of the full moon and begins to change into a werewolf as heÂ’s forgotten to take his potion. Pettigrew changes and escapes before Harry can stop him. They go to get help but they see Sirius with the Dementors coming towards him. They close in around Harry, Hermione and Sirius getting ready to perform the kiss. Harry tries his patronus but then a Dementor goes to give Harry the kiss as well and before he faints something is driving the Dementors away and he thinks he sees his dad going back across the lake.

Harry wakes up in the hospital wing. Snape has handed over Sirius and the Dementors will be going for him. Harry and Hermione insist heÂ’s innocent but Snape has them all convinced apart from Dumbledore. He has a word with Harry and Hermione in private and tells Hermione that 3 turns should do it so that 2 lives will be saved that night. Hermione knows what he is on about, all year she has been using a time turner to travel back in time so she can do all of her lessons.

They travel back in time and first save Buckbeak from execution. They hide him and wait until Sirius is locked in the tower. Harry though has to see if it was his dad who rescued him, it wasn't it was his future self. They save Sirius from the tower and he flies off with Buckbeak. They manage to get back to the hospital wing just in time for Dumbledore to lock them in. Snape is furious that Black has escaped and blames Harry but he's been locked up all the time.[/quote:post_uid0]

Hm.. I guess this is still hard to understand without having read the entire book...

The fact is, the dementors would have killed him if his future self didn't summon a patronus to stop them. :D

I'm going to buy Harry Potter 5, by the way. :)[/color:post_uid0]

[color=#000000:post_uid0]That does sound rather complex to me.

Sirius? So that's where that name came from... (In my d&d group there's character named Sirius)[/color:post_uid0]

[color=#000000:post_uid0]Well, there is a star of the same name too (Sirius Canus Majoris AKA the Dog Star).

And my sister's copy of HP5 is already on the way. She's promised to let me read it at some point.

And I still think all of the above paradoxes would be coved by the [i:post_uid0]Timescape[/i:post_uid0] explanation.[/color:post_uid0]

[color=#000000:post_uid0][quote:post_uid0]And I still think all of the above paradoxes would be coved by the Timescape explanation.[/quote:post_uid0]
I think so too, but I'm not exactly sure what would happen if the fact that someone or something gets send back in time doesn't change itself. Would that mean there is an infinite number of dimensions, which are exactly the same?[/color:post_uid0]

[color=#000000:post_uid0]Well, if there are already potentially an infinite number of alternate timestreams existing (which of course is only theorised), then it's not going to make much of a difference if a few errant time-travelers create a few more.[/color:post_uid0]

[color=#000000:post_uid0][quote:post_uid0]Well, there is a star of the same name too (Sirius Canus Majoris AKA the Dog Star).

[/quote:post_uid0]

Warning: Science Geek in the room.

Alpha Canis Majoris, to be pedantic, and I'm still not sure about the ending. My astronomy text says the names are supposed to be the "possessive" form of the constellation name (or something), but my Latin grammar doesn't match my vocabulary (which isn't all that classically impressive to begin with).[/color:post_uid0]

[color=#000000:post_uid0]Well, it's not surprising considering that the bulk of my knowledge of astronomy has been gleaned from Patrick Moore on [i:post_uid0]The Sky at Night[/i:post_uid0].[/color:post_uid0]

[color=#000000:post_uid0][quote:post_uid0="catalina_marina"]
What if he was originally saved by someone else, but, because he travelled back, somehow he wasn't, so he had to do it himself. He would have disrupted the timeline, by actually getting his younger self killed, but he corrected it, by saving himself, so that it all works out anyway.[/quote:post_uid0]
No no no! :D He originally did save himself. [i:post_uid0]There was no "alternate timeline" involved.[/i:post_uid0] No more so than someone who, by walking along a sidewalk and suddenly stepping off into the grass, walking back a few paces, and then stepping back onto the sidewalk to resume his or her original path, is walking on two different sidewalks.[/color:post_uid0]

[color=#000000:post_uid0]Very [i:post_uid0]Bill and Ted[/i:post_uid0].[/color:post_uid0]

[color=#000000:post_uid0]Here is how I see time travel. The past can not be changed, and if you do go back to change something, you had already seen the result of the change before you go back. Its like you were already part of the past even though you had not gone back to change it. You go back thinking you are going to change the result, but you end up creating that result. I think the best example is the Voyager episode where they were caught in some anomaly, its one of the first episodes. They recieved a distress call, which happened to be their own call that they made later.[/color:post_uid0]

[color=#000000:post_uid0]And that's called a predestination paradox. [b:post_uid0]The[/b:post_uid0] way to avoid a temporal paradox/loop for any episode/movie.[/color:post_uid0]

[color=#000000:post_uid0]But how do you explain the ep with planet that had been destroyed then? Voyager comes to a planet where all the population has died a couple of days ago. When they go to investigate it, they find a temporal disturbance. Janeway and Paris go in it, and the others, while looking for them, cause some sort of pulse (or something), to get them back, which is the cause the planet got extinct in the first place. So far so good, but then Janeway and Paris figure out how to stop the pulse and they do. Therefor the planet never was extinct, and they never went back in time to stop it. So why was the planet extinct in the first place?[/color:post_uid0]

[color=#000000:post_uid0]It wasn't. ;)[/color:post_uid0]