Monday, February 1, 2010

My Thoughts on Time Travel

Last night we watched the new Star Trek movie on DVD. We had seen it in the theater, loved it, and I got the DVD for Christmas. We finally had a chance to watch it and so we did. The movie involves time travel a bit, and I had a short discussion Teresa and her parents on how it worked. It got me thinking. I have some pretty strong feelings when it comes to time travel in my science fiction. Sometimes it's done well, and sometimes it's done very poorly. When it's done poorly, it grates on me and takes a lot of the enjoyment out of whatever I'm watching or reading. Since it seems to be something I have such a strong opinion on, I felt it was worth putting on my blog. Before I get into this, be forewarned I'm probably going to talk about books, TV, and movies I've seen that involve time travel, in which case there may be spoilers for those things.

We'll start with the movie. In this case, I think it was done very well, and the plot device itself lends itself to a new franchise of Star Trek that doesn't interfere at all with the previous iterations of Star Trek. Here's how it works. In the movie, people from the future travel through a black hole into the past. At the moment they enter the past, they essentially change history. But they don't change their own history. They have created an alternate reality. Think of it like this. If I go back in time and prevent my parents from meeting. I won't be born. But I was born, since I went back in time to prevent my parents from meeting. So rather that have this paradox, we go with an alternate reality. In the reality I came from, my parents met, I was born, and so forth. In this new reality that I created by prevent my parents from meeting, I will never exist. In this manner, I could travel through time creating any number of realities through my actions without interfering with my own. And when I was tired of messing with things, I could return to my own reality where nothing was different.

The reason this works so well for Trek is because now the crew of the Enterprise can have their own adventures without having to explain why it's different from the adventures of the original series TV show and movies. The moment Nero entered the past, nothing would be the same for the people in that reality. Kirk's life was changed immediately because his father died that day that the timeline was affected, and by proxy so was everyone on the Enterprise. It also explains why the old Spock can't predict the future for the other Spock and Kirk. Because in this reality, things could turn out very differently.

Another good way to do time travel is how they've done it on the TV show, Lost. In Lost, there is no alternate reality (that we know of...). It's all on one time line. But they stick to the mantra that whatever happened, happened. Essentially what this means is that even if I could go back in time on my same timeline, I couldn't change anything in the past because it's already happened. I may not go back to 1970 until I'm 30, 2 years from now, but my future self has already existed in 1970. If I went back on my same time line to prevent my parents from meeting, I wouldn't be able to. The evidence is that I exist. In Lost, everything that the main characters did in the past had already happened when they first showed up on the island. They didn't know it because they hadn't done it yet, but it had happened. My own personal theory, in keeping in line with what ever happened, happened, is that the end of last season has no effect on what will happen to the main characters. The same thing that happened before they went to the past will still happen.

I think one of the episodes involved a character saying that he was wrong about whatever happened, happened. But I think they used that episode to prove him wrong in his assumption. I read series of books that involved warp portals that led to the past. The premise in the book was that the universe would not allow a paradox, so if you went back in time to shoot someone before their time, the gun would misfire, or the bullet would miss, or something of that nature. You could not change the past, even though you could travel to it.

Essentially all of this is an effort to avoid a paradox. I can't go back in time and kill myself because then I wouldn't be able to grow up, go back in time and kill myself. (Note: Alternate realities allow for this, but I wouldn't be killing me, I'd be killing an alternate me.)

So those are my favored time travel applications. Let's look at some bad ones.

Back to the Future. I love these movies. They're fun, and they're geek movies. But the way they do time travel isn't very well done. Marty fails to get his parents together and he starts to disappear. What the heck? And then when he changes things, he can remember how it used to be, but his parents and friends can't. They have instantly changed to reflect the things that Marty changed in the past. This happened recently on Heroes too when Hiro got Ando and Hiro's sister to fall in love at the carnival. When he got back to the present, it's like Ando and his sister were different people. But Hiro remembered what the old timeline used to be. The reason I don't like this way of time travel is because it's confusing. If Hiro changes the past, then there's nothing to go back and change when he gets to the future. Time lines are being created and destroyed. What happens to the past that was erased? If it didn't happen, then why did it need to be changed?

Star Trek actually uses time travel a lot in the other TV shows and movies. Probably the most frustrating thing with this is that they aren't consistent with the theory of time travel they use. Sometimes they're going to alternate universes. Sometimes they're changing their own past Think Tasha Yar as a Romulan, or the crew of DS9 having dopplegangers in a parallel universe. And then just recently, Teresa and I watched the episodes where they discover Data's head and then go back in time. This time, they follow the whatever happened, happened idea. It's also interesting to note that what caused them to travel back in time, was the discovery of something that they left back in the past. Think about it.

For me, it all stems from how believable it is. Star Trek is fiction, but it's supposed to be believable. We're supposed to think that this stuff could actually happen in the future, even if it is a lot of techno babble and untested theories and out and out fiction. When a show or movie does something that just doesn't even make sense, even in the context of it's own universe, it takes a lot out of the enjoyment for me, and I think it's more confusing for much of the audience.

Lost's final season starts tomorrow, and I'm eager to find out if they stick with the same theory of time travel. If they don't, I'll be disappointed, but I'm fairly certain they well. The producers of Lost also directed and produced Star Trek.

I should note a couple extra things. Nearly all of these examples involve traveling in time to the past. Traveling to the past has the hardest implications for paradoxes and manipulating things. Traveling to the future is less exciting. It's more about seeing what people are like a given number of years from now. If you change something in the future, that doesn't affect anything about the course of the future. It just means a person from the past did the affecting instead of a person from the future-present. Also, as much as I hope we someday have star ships and travel in space, I don't actually think time travel is possible. There are two many complications and chances for paradox. Alternate reality is probably the most likely, and it's still a hard thing to grasp and prove today. Time will tell.


Jesse said...

Hey Tj - thanks for this great post!! I also really enjoy time travel theories, and your explanations were really good. I just recently saw Star Trek for the first time and the time travel aspect was a bit confusing at first (mainly cause I don't have any Star Trek knowledge). Here's a few more thoughts: 

I can see why you like the alternate realities theory b/c it eliminates the paradoxes. But I actually don't like it much. To me, it cheapens the value of this reality, or any reality. Mainly because of my religious as spiritual worldview, I can't see multiple realities existing. Some theories apply this to free will and choices as well, saying basically every decision has been made and the realities are continually splitting off in correspondance with the possible realities. If it is possible, it is, just in another reality. What you experience now just happens to be one of many. 

Perhaps my biggest problem with that whole idea is that I believe human consciousness is a vastly important and significant. To split my being, or duplicate it, seems to cheapen that. 

Have you seen the show "Flash Forward" that started this year? The book is also really good and deals with time travel a lot. It mainly addresses future time travel, and so I thought of it when you said traveling the future doesn't present a paradox. In FF, there are man paradoxes because they see their future, return to the present and then make decisions in the present based upon their knowledge of the future, but these present decisions make the future come true the way they saw it. It's like a circular argument. 

Fun stuff!!! 

Jim said...

The problem with time travel in Star Trek (as a whole) is that it's inconsistent. There's alternate histories and rewriting chronologies and closed time loops all in the same series. BTTF's scheme is physically implausible but at least it's relatively uniform through the series. If you want something harder to chew on, go for something like 12 Monkeys or (if you're feeling really ambitious) Primer.

The jury's still out about time travel into the past in real life. (Travel into the future is trivial, of course -- you get that for free just by waiting, or playing games with time dilation at high fractions of c if you're impatient.) I'm more or less with Hawking on this one, who proposes a Chronology Protection Conjecture: that there's some physical phenomenon which prevents upstream travel. I like Visser feedback as the specific mechanism. General Relativity kind of muddied the water a bit though, because you can't even globally define what "past" and "future" are. It's possible to create paths through appropriately curved spacetime that are always timelike but can still intersect themselves.

gmazeroth said...

@Jesse I totally understand what you mean by cheapening our own existence by claiming we exist many times over in other realities. I don't really think it works that way. I'm more inclined to believe in alternate universes with wholly contained peoples in it, as opposed to mirror universes with different versions of us.

I haven't seen Flash Forward, but I might try and take a look sometime. The situation you described still seems similar to me though. You're trying to change the future by acting in the past. In this sense, the past just happens to be our present and we're working off of assumptions we've seen of the future. The fact that it ends up being the same anyway would support the whatever happened, happened theory that we can't change anything, even if we think we're trying to.

@Jim Wow, you're blowing me away here! I have seen 12 monkeys (though it's been awhile), and I alluded to that kind of circumstance with the Data's head thing, I think. The idea that something you did in the past is what causes you to go to the past, and then you make sure and do the thing that led you there so you go there. Very tricky stuff.

I also totally agree on the inconsistency of Star Trek, which is what makes it so frustrating, even though I love Star Trek. I actually didn't get in to any of the actual theories on time travel. Relativity and what not. But I did think of some other examples in TV and cinema such as the movie Frequency, and that one with Christopher Reeve where he goes back in time just by imagining himself to be there. Somewhere in Time? Can't remember. It was a love story too and it was pretty sad. Again, that one had a lot of the thing that sent me to the past is something I did in the past vibes in it.

Jim said...

(Cue Miles O'Brien and another Miles O'Brien saying "I hate temporal mechanics!" in unison.)

There's a good article on sci-fi chronophysics here. I kind of like Larry Niven's take: any universe which permits backwards time travel eventually, through successive re-writes, ends up in a state in which time travel is never actually discovered or used. Niven also explored (in All the Myriad Ways) how taking many-worlds at face value tends to destroy all narrative tension, especially if there is communication between the alternate worlds.

*~Jen~* said...

I will never stop blaming you for how nerdy I am.