Is altering the future possible?(In Theory)
 

A lot of people seem to think that if you travel back in time and alter the past that the future would change drasticly, but i disagree. Dosen't it stand to reason that time would take into the fact that you are changing the past? So the way i see it, the future wouldn't change because you changed the past. What do you think?

Depends on the view... if everything is predetermined then no, nothing changes, you were suppsoed to go back in time and do something, and the past only happened the way it did because you interveened. If there is no predetermination then it really doesn't matter. You go back in time and change anything, and then a million different things could happen.

A) multiple universes, there are an infinite amount of possibilities for every single choice, and in any one universe one of the chioces has been taken (a million universes split off for every choice ever made).

B) you go back, and everything is different since to them the past is the way you changed it to, they don't remember anything else since to them this is normal. But you somehow have your memories since you were back in time and somehoe your place in the timeline allowed your mind to not be changed or soemthing...

C) as above, except your memory is chagned as well, though it would cause soem intersting paradoxes since you wouldn't know what you changed even though you jsut did it...

D)The universe implodes/explodes, basically it just ends...

It can occasionally make me feel sick to think about this in too much detail. But it's an interest concept and subject to think about. I guess until someone actually invents time travel within this lifetime, I'm open to opinion. ^^

Just as a point of reference, because this was one story I actually did enjoy in school:

Sound of Thunder

And if you're into the effects of time travel and the possible consequences it has on life:

The Butterfly Effect

I believe altering the future is totally impossible, because the future does not exist.

I could predict what I'll be doing in 2 hours, but that could be completely changed because I found something else more important. The "future" is made by choices. It does not exist already, it is made.

Melfice, I believe he was actually referring to altering the present by going back in time and changing the past.

Now this may or may not be possible depending on which time travel theory you believe.

Predestination or the Orcarina of Time Theory
Everything that you do in the past you had done in your current timeline. I.E. if you ruined the windmill in the past, eventually you'll go back in time and ruin the windmill.

The Back to the Future Theory
If you go back in time and change something, you change events from that point foward. I.E. If I go back in time and shoot Hitler when he's 5 years old, then he can't possibly start WW2. And only the timetravel will remember what Hitler would have done.

Will post more theories later.

The Multiple Universes theory is one I think would be more possible.

You change something in the past... it creates a different present. When you return to your own time, your world and events are unchanged, but because you changed something an alternate present was created and the changes are applied there.

Of course... there is the Langoliers possiblity... Once the past is gone, you can't go back because it doesn't exist anymore.


Then there is this...

If you go back in time to change something and change it, it creates a paradox of sorts. If you change whatever it was and it never happened, you would have no reason to go back in time and change it. Therefore, unless you retain the memory of what needed to be changed, it would never happen and then you wouldn't need to go back and change it, therefore it would happen causing you to want to go back and change it. The cycle would continue indefinitely, but I think this would only matter to things directly affecting you. If you go back and change things for other people that don't affect you or history in any major way, then you could change them without the paradox being created. Like going back and unintentionally saving someone from being hit by a car.

Pardon me... I think my head is going to implode now. Someone please go back in tme and tell me not to think too hard about this when I post...

::implosion::

I personally think that if you go back in time, then you change yourself back to the way you were, memories and all.
And that if you change things, then you remember them as you changed them.
Thirdly I think we do this all the time.
Blow your mind, I will.
And doesn't this belong in discussion?

One of the most basic tenants of Relativity is that infromation doesn't travel faster than light. Sometimes it seems to but in general infromation is limited to the speed of light. This leads me to a rather strange conclusion about time. If you travel back in time without actually traveling that distance in time and change something. Then skip back forward without traveling through the intervening time once again you end up right back where you were. The change you made in history happened but it spreads through time at the speed which time moves. Since you did not travel through time at the speed of time you beat it back to the future. Once you reenter the timeline you begin to move forward at the speed of time again; thus you stay forever ahead of your alteration.

For example: You magically zip 5 minutes into the past and kill a lab tech. You then zip back to the point you left. If you think of time as a river what you did was jump out run backwards much faster than the current. Then dropped something in and ran back to where you left all so fast the water didn't have time to move. Assuming you and the thing you dropped in the river travel at exactly the speed of the current it will never catch up to you. Thus you can return to your old time line quite safe in the knowledge no one will know what you did or even that the lab tech is dead. If you used the travel close to the speed of light slow down time method of getting back to the future, however, you would find the altered history when you got back to where you left.

Edit: Oh and want to really blow your mind consider this. A man travels into the future and finds himself waiting. On a whim he pushes his future counter part into the timemachine and sends him back in time. As the guy from the past continues into the future do the actions of the him he sent into the past change what he expirences?

I don't think it's really discussion material. Not a lot of people will really want to get too in depth about this, because it is REALLY confusing. Makes my head dizzy. If it does have more lengthy thought out replies, I may consider moving it.

The thing that makes me most confused is thinking of the various different ways things could change/not change. I mean, if I were to hop back in time, change something, and then come back, perhaps nothing would have changed. Because I'd of already technically changed it. Thus different parallel universes are brought into play and then I think of space and it's infinity and my head feels like it wants to implode, much like someone else said.

Say you went back in time and killed the president before he made the decision to go to war with Iraq. Would we still have gone?

OoT theory: The vice president probably would have made the move and went ahead. But...the whole killing thing and catching Saddam probably wouldn't have happened.

Sithdarths theory: It would've went scheduled as planned but you'd know that you did it so when it happenedno one else would ever know and it would happen long after Saddam was captured.

If anyone has a different theory please share.