Working out the numbers, the chances of 14 coin flips in a row being equal is 1 in 8,192. (The linked article says 1 in 16,000, which comes from 2^14; but that first coin flip has to be something, so the chances of 14 in a row are really 1 in 2^13. The anomaly would be just as strange if the AFC had won every time.) That’s a better than 3.8-sigma effect! Enough to call a press conference, if this were particle physics.

The question is … is this really a signal, or did we just get lucky? Is it a fair coin and the NFC has just been the happy recipient of a statistical fluctuation, or is there something fishy about the coin? Remember Barry Greenstein’s parable about how different people compute probabilities.

And let it be a lesson the next time you’re excited about 3-sigma anomalies.

Thing the first is that Morgan Freeman, many years before he went through the wormhole, was a regular on The Electric Company, along with performers like Rita Moreno and Bill Cosby. (Via Quantum Diaries, of all places.) This was public television’s show from the 70′s that was meant for kids who had moved on from Sesame Street — I was more of a Zoom kid myself, but I must have seen Electric Company episodes with Freeman playing hip dude Easy Reader.

Thing the second is that Easy Reader’s theme song, sung in the clip above, is a dead ringer for Amy Winehouse’s “Rehab.” Flip back and forth between playing them if you don’t believe me. So much so, I am told, that DJ’s in clubs will sometimes mix the two tunes together. Not at the clubs I go to, I guess.

The bad news: Sheldon Cooper makes fun of you on national TV.

Of course you don’t need to watch the ceremonies to learn what all the scientists are wearing this year. I am reliably informed that a regular tuxedo is not good enough; you need to go full white tie and tails. (Interestingly, the Peace Prize is more casual; black tie or “national costume” is perfectly acceptable.)

I am generally a fan of the two-party system. Sadly, at the moment in this country, one of the parties is completely crazy.

Update: Sorry that the video isn’t available outside the U.S. Note that Lisa Randall was a guest earlier on the show.

Someone shows you a coin with a head and a tail on it. You watch him flip it ten times and all ten times it comes up heads. What is the probability that it will come up heads on the eleventh flip?

A novice gambler would tell you, “Tails is more likely than heads, since things have to even out and tails is due to come up.”

A math student would tell you, “We can’t predict the future from the past. The odds are still even.”

A professional gambler would say, “There must be something wrong with the coin or the way it is being flipped. I wouldn’t bet with the guy flipping it, but I’d bet someone else that heads will come up again.”

Yes I know the math student would really say “individual trials are uncorrelated,” not “we can’t predict the future from the past.” The lesson still holds.

Happy Labor Day, everyone.

Also, needless to say, it did a great job of advancing the secret atheist agenda.

And the science? I was pretty happy with how it turned out. It was made clear that all of the super-ness was ultimately based on (some hypothetical set of) laws of physics, not just magic pulled out of the air — without descending into a dreadful level of midichlorian-like overexplanation. There is one phrase used in the movie that I think is directly attributable to my input: “Einstein-Rosen bridge.” This came about from a conversation between producer Kevin Feige and me that went something like this:

KF: We need the Bifrost Bridge to provide a way for the characters to travel great distances in space in a very short period of time.

SC: Sure, you probably want to say that it makes use of wormholes.

KF: Well, we can’t call it a “wormhole.”

SC: Why not?

KF: Sounds too Nineties.

SC: I suppose … you could call it an “Einstein-Rosen bridge.” Means the same thing.

So naturally, in the finished film, Jane Foster calls it an Einstein-Rosen bridge, and someone says “what’s that?”, and she replies “it’s a wormhole.”

Jennifer pointed out afterward that, while Jane Foster’s scientist character was appealing and a good role model, they did miss a chance to make use of her love of science in the service of the story. While we see our Earth-based heroes zooming around the desert chasing atmospheric anomalies, the connection to astrophysics is never explained, nor do they really talk that much about science. In one scene Jane makes goo-goo eyes at Thor as he talks about all this apparent magic just being very advanced science. Goo-goo eyes are fine, but any real scientist in that situation would have started asking questions about spacetime and exotic matter and quantum stability and so on. It would have been great if we had seen Jane fall for Thor, not because of what he looked like without his shirt on, but because behind the gruff exterior he knew more deep physics than she did. Maybe in a sequel.

I hinted that there was one thing all the scientists warned the moviemakers not to do, and indeed they didn’t do it. In one conception, the planet of the Frost Giants was to be shaped like a disk. Not a ringworld-style band that used rotation to mimic gravity, but just a flat planet in the shape of a record (or a DVD, for you youngsters). Which is fine, if somewhat fanciful. The potential disaster was that they wanted to have a big fight scene where frost giants would fall off the edge of the planet. Pulled by … what, exactly? Total gravity Fail. Fortunately they ditched that idea, although the concept survived in less egregious form in the depiction of Asgard, which looks like a mountain that sits on top of a galaxy. That also makes no sense, but it’s so far from trying to make sense that the audience just sees it as poetic license, not a simple mistake.

Unlike TRON: Legacy, where we came in after the screenplay had been drafted, on Thor we came in near the beginning. Marvel had done a lot of work on the idea, but there wasn’t yet a script. The Exchange set up a consult meeting with director Kenneth Branagh, the screenwriter, and few people on the design and production side of things, along with three scientists — Jim Hartle from USCB, Kevin Hand from JPL, and myself.

We bandied around lots of issues relating to the Thor universe and how it fit in with Marvel’s bigger plans. Once there was a script, I came in to read it and offer some more comments. Since that time, the script was re-written by the dynamic duo of Ash Miller and Zack Stentz, and I haven’t actually seen the film yet, so I can’t speak to what kind of impact we had in the end. Let’s just say that there was one thing in particular that they were planning on doing in the movie that drove all the scientists batty — I think we convinced them to fix it, but we’ll have to see. And once filming started, they recruited Caltech student Kevin Hickerson to help with the tech-gadgetry end of things. So I have high hopes. (Early reviews are very positive. And of course, Agent Coulson returns, with a larger role than in the Iron Man films. Everyone loves Agent Coulson.)

You might be wondering, where is there room for any sort of science in a comic-book movie about a Norse god in a red cape who swings a magical hammer? Well I’m glad you asked. Actually there were a couple of different things where the movie people were very interested in our input. One was constructing a coherent framework for the Marvel universe — ultimately, this story about Thor the thunder god is going to have to be compatible with Tony Stark’s Iron Man world, since the two characters are both part of the Avengers. (I also got to read the script for that, and yes — it is as great as the rumors suggest.)

Kevin Feige, president of production at Marvel Studios, is a huge proponent of having the world of these films ultimately “make sense.” It’s not our world, obviously, but there needs to be a set of “natural laws” that keeps things in order — not just for Iron Man and Thor, but all the way up to Doctor Strange, the Sorcerer Supreme who will get his own movie before too long. The thinking here is very much based on Arthur C. Clarke’s “any sufficiently advanced technology is indistinguishable from magic.” In the trailer above, Thor basically gives exactly this pitch to Jane Foster.

That’s the other area where we science consultants were able to help out: in shaping Natalie Portman’s character of Jane Foster. In the original comic books Foster was a nurse, but they wanted to update her considerably for the movie. So they hit on the idea that she could be a scientist, but what kind of scientist? (I argued that she be an experimental physicist.) What kind of position would she hold? Could there be tension with her academic supervisor? What kind of posters does a young physicist have on her apartment wall?

Again, I haven’t seen the movie, but I’m very hopeful that Jane Foster ends up being a strong character and a good representation of scientists. Natalie Portman seems to think so — you can read here and here about how she feels this role was an opportunity to do something different and important.

“Ken and I talked a lot before we started about how to make Jane a realistic scientist on screen — (and) not just make her (like) Denise Richards in Bond who wears . . . glasses and so she’s a real scientist,” Portman said. “We talked about how real scientists are like artists: They are able to imagine things that aren’t there. And to give (Jane) this sense that she’s sort of frazzled and she’s often thinking in abstractions.”

I do know people like that, yes. And who knows what young person might see the movie and get some inspiration? Portman again:

“I got to read all of these biographies of female scientists like Rosalind Franklin who actually discovered the DNA double helix but didn’t get the credit for it,” she said. “The struggles they had and the way that they thought — I was like, ‘What a great opportunity, in a very big movie that is going to be seen by a lot of people, to have a woman as a scientist.’ She’s a very serious scientist. Because in the comic she’s a nurse and now they made her an astrophysicist. Really, I know it sounds silly, but it is those little things that makes girls think it’s possible. It doesn’t give them a [role] model of ‘Oh, I just have to dress cute in movies.’”

Right on. We all know that no amount of superhero blockbusters are going to suddenly create a science-literate public. But a positive portrayal here and there can help lower the barriers between scientists and everyone else. Any movie that can inspire young girls and feature a magical flying hammer that smashes things is okay in my book.

More recently Jim has written another book, The Amazing Story of Quantum Mechanics. But even without superheroes in the title, everything Jim thinks about ends up being relevant to movies before too long. The new movie Source Code features a twist at the end that involves — you guessed it — quantum mechanics. Jim has applied his physicist super-powers to unraveling what it all means, and was kind enough to share his thoughts with us in this guest post.

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There is an interesting discussion taking place on the internets concerning the ending of the newly released film SOURCE CODE, that suggests that the film concludes with a paradox. I believe that any such paradox can be resolved – with Physics!

This entire post is one big honkin’ SPOILER, so if you want to read about the final twist ending of a film without having seen said film – by all means, read on, MacDuff!

In SOURCE CODE, Jake Gyllenhaal plays US helicopter pilot Colter Stevens, whose consciousness is inserted into another man’s body (Sean Fentress, a school teacher in Chicago) through a procedure that requires a miracle exception from the laws of nature (involving quantum mechanics and “parabolic calculus” – by the way, there is no such thing as parabolic calculus). Thanks to some technobabble (or as Q-Bert on Futurama would describe it – weapons grade bolognium) Colter’s mind can only enter Sean’s body in the last eight minutes of Sean’s life. As Sean is sitting on a city bound Chicago commuter train, on which a bomb will explode at 7:58 AM, killing everyone aboard, the goal is for Colter to ascertain who planted the bomb. He cannot stop it from exploding, he is told, because that has already happened. He cannot affect the past, but he can bring information obtained in the past back to his present time. Learning the identity of the bomber would enable the authorities to prevent the detonation of a threatened second “dirty atomic” bomb is downtown Chicago.

While the above can be discerned from the movie trailer, what I am going to discuss next involves the actual ending of the film, and if you do not want this ending spoiled, you should stop reading now.

Colter learns that the reason his last memory is being attacked in his helicopter in Afghanistan is that he in fact died in the crash. His mangled body is kept artificially alive, and his brain can be activated, and sent to inhabit the body of Sean Fentress (who happens to be a neurological match). At the end of the film, after multiple failed attempts, Colter manages to identify the bomber. Providing this information to Col. Goodwin (a military officer played by Vera Farmiga) and Prof. Rutlidge (the great Jeffrey Wright), the scientist who designed the Source Code project, the terrorist is caught before he can set off the second bomb, but after, of course, the first bomb on the Chicago train explodes.

It is left somewhat vague as to whether Colter is going to parallel realities, a la the Many World’s interpretation of Quantum Mechanics, or whether he is engaging in a quantum/ neurological simulation. If the former (which seems to be borne out by the ending) then this would tie into notions of time travel being explored in the context of quantum gravity. That is, if one could time travel into the past, you need not fear any Grandfather paradox (what if you killed your ancestor – preventing your birth, but then you would not be able to travel back in time to ice Grandpa). Some physicists argue that time travel is only possible via parallel realities. You do not go back in time in your own reality, but to an alternate Earth’s past. You can thus kill as many grandparents as you have bullets, remaining safe in your own timeline. In any event it is assumed that the bomber is the same person every time Colter enters the Source Code.

While everyone is celebrating the capture of the bomber, the first successful trial of the Source Code project, Colter convinces Goodwin to send him back one last time, to try to save the passengers on the train. At the end of the eight minutes, he convinces Goodwin to terminate his life support, allowing him to die in actuality, as the world and his father believe happened months ago in Afghanistan. Needless to say, he manages to stop the first bomb from exploding on the train, hands the bomber to the authorities, and kisses his love interest just as the eight minute mark is reached. We see Goodwin make good on her promise and end his life support at that moment, at which point she is arrested my the military police for acting against Rutlidge’s instructions.

On the train however, Sean/Colter is still alive after the kiss. The film implies that he goes on to live happily ever after in Sean’s body, with Colter’s mind, while Colter’s deformed body remains at the Nellis laboratory on life support. As the bomb never went off on the Chicago train – there was no reason to activate Coulter and send him into the Source Code, and the project awaits its first true trial by fire. Thus it is indicated that we are witnessing two alternate realities – one where Goodwin is arrested after pulling the plug on Colter following the successful application of the Source Code, and the other where Sean/Colter is still alive, where the Source Code project has not been activated.

Among the many discussions I’ve noted on the web about the ending of this film, I wish to address two particular issues that are being debated by the Hive Mind. In the film’s final reality, where the bomb does not explode on the train – does Colter’s consciousness reside in two places at once? And, what happens to Sean Fentriss’ consciousness in this final reality?

Reasonable people may reach different conclusions concerning these two points. As I am a physics professor – I will tell you the RIGHT answers!

(1) In the final reality – Colter is NOT consciousness in two places at once. He is awake and aware in Sean’s body and at the same time his damaged body is in the Nellis lab – IN A NON-CONSCIOUS STATE. He is not awake and aware in the lab at Nellis, he can not initiate motion or form an independent coherent thought. He is in essence brain dead, kept artificially alive until there is a time and need for him to be activated (if there is a terrorist attack).

Even if he is activated – this would NOT influence or affect Colter in Sean’s body, as it would take place in Sean/Colter’s FUTURE. Remember he was sent back to Chicago at 7:50 AM – the bomb exploded at 7:58. Time progresses forward for both Sean/Colter and Nellis/Colter at the same rate. This was why Goodwin and Rutlidge were upset about how many trials it was taking – for each trial burned up a minimum of eight minutes, and brought the second explosion closer to happening.

What you are doing and thinking now is not affected by what you will be doing and thinking several hours from now. Do you know what you will be thinking about several hours from now (ok – for the guys this is an easy one). Nellis/Colter may not be activated for weeks/months/years later. But even if he is – Sean/Coulter can live his life, unaffected by what is happening in his future. There is no paradox, for Colter in Sean’s body is only awake and conscious at one point in time. Colter is NOT like Schrodinger’s cat, in two different conscious states simultaneously, as they are separated in time.

(2) What happened to Sean’s consciousness? Here there is a potential problem. Basically I believe Sean is dead. When Colter’s mind jumps into his body, it over-writes Sean’s consciousness. Rutlidge probably knows this, and ignores the ethical issues. Sean will be dead when the bomb explodes after all, and Rutlidge believes that cannot be changed. By sending Colter into Sean’s body, he robs Sean of the last eight minutes of his life. As Sean is unaware that a bomb will explode, killing him and everyone on board, he would not do anything extraordinary in those eight minutes. Rutlidge probably believes that it is acceptable to sacrifice the last eight minutes of one man’s life in order to save millions of lives if they can prevent the second bomb blast in downtown Chicago. Every time Coulter enters the Source Code at 7:50 AM, he essentially kills Sean. Sean will die in every reality where Colter does not enter the code, and he will also die in all N – 1 realities where he does – so this is an ethical problem of order 1/N where N goes to infinity.

Alternatively, Sean may be alive in Colter’s damaged body – but there was no suggestion that something like that was happening. Here I’m taking the Quantum Leap analogy too literally. (There is a wonderful tip of the hat to Quantum Leap – listen carefully to Coulter’s Dad).

Sorry this is so long. Never ask a professor a simple question – you always get a lecture in reply!

Besides the undeniable cleverness, there is some deeper metaphorical message here. Take it for what you will.

But … Science? Well, yes, a little. Dan Vergano has some of the scoop. There was a huge amount of science and technology that went into making the film, of course, but also some underlying the story. The director, Joe Kosinski, and producers, Sean Bailey and Jeff Silver, were very enthusiastic about science from the start, and always wanted to learn more. At the same time, it’s essentially a fantasy movie, not a documentary or even hard SF, and nobody was tempted to over-explain what was going on. Our consult occurred after the initial script was already in place, so it wasn’t as if we exerted a noticeable influence on the direction of the plot. What we did was help fill in the backstory. If there is a sequel, some of the ideas we talked about could end up playing a more substantial role.

Early in the movie, the Alan Bradley character waxes enthusiastic about the advances of technology, and includes a bit of technobabble about “genetic algorithms” and “quantum teleportation.” But in fact, that bit of babble is very relevant. One of the most interesting aspects of the new grid world is the existence of “Isos” — programs that arose spontaneously, rather than being constructed by a programmer. And of course one of the main conceptual hurdles in the plot is how you teleport a physical human being into the grid. We talked a lot in the consult about conservation of mass. And in the final result, the laser that miraculously disassembles Sam Flynn and transports him into the grid is equipped with canisters of raw materials (oxygen, carbon, etc.) that can be used to re-assemble people back into reality. You won’t even notice them when you watch the movie, but they’re there, and I count that as a small victory.

Realistic science that you’d be happy to show your class? No. But a decent example of how a bit of science can help add depth to a story. Scientists can play a much more substantial if they consult right at the beginning, when a script is first coming together — and hopefully we’ll start seeing the fruits of some of those consultations before too long. But every little bit helps. A movie like TRON doesn’t force you to think against your will — you can perfectly well just sit back, turn off your brain, and enjoy the ride. But if you’re predisposed to thinking, there’s plenty of food for thought.

There are more.

I’m posting it here because, as wonderful as the talk is, I disagree with it at a deep level. Yes, indeed, the concept of “mystery” is absolutely crucial to what makes a story compelling. But I think Abrams takes the idea too far, valorizing mystery for its own sake, rather than as motivation for the characters and the audience to try to solve the mystery. The reason why mysteries are interesting is because we want to figure them out! If they are simply irreducibly mysterious — if there is no sensible explanation that ultimately makes sense of all the clues — then it’s simply frustrating, not magical.

This isn’t just jousting with words — it has consequences for how stories are told. That’s why I chose Star Trek as my one movie to complain about in our Comic-Con panel last summer (as much as I enjoyed the movie overall). The dangerous planet-killing substance in that case was “red matter.” Shiny, red, and ominous-looking, red matter is not anything known to modern science. Which is fine; modern science doesn’t know about warp drive or Vulcans, either, but they work well in this particular fictional context. The problem is that red matter wasn’t associated with any sensible properties even within this fictional world. We never knew where it came from, why it did what it did, how it would react to different circumstances, etc. (Why did it have to be deposited in the exact middle of a planet, rather than just splashed on the surface?) It was simply “mysterious.” But this particular bit of mystery didn’t make it more compelling — it prevented the audience from engaging with the menace that the red matter presented. If we knew something about it, we wouldn’t just be going “okay, that’s the bad stuff, gotcha”; we’d be following along as Kirk and Spock tried to defuse the danger, understanding what might and might not do the trick. Not all mystery is good storytelling — sometimes a bit of understanding helps grab the attention.

Just to draw the distinctions even more carefully, let me come out in favor of ambiguity as opposed to mystery. The end of Inception is quite famously amenable to more than one interpretation. (To go back further, ask whether Deckard was a replicant.) This drives people crazy, trying to figure out which one is “right,” an impulse I think is misguided. It’s okay to accept that we don’t know all the answers! But in theses cases we understand quite well the space of all possible answers. There is no black box whose operation is simply mysterious. We don’t need to know all the final answers once and for all; but it’s better storytelling if we understand what the answers could be, and that they make sense to us.

Hopefully it’s not too hard to read between the lines here, and see the consequences for science as well as for movies. There are those who argue that science destroys the magic of the world by figuring things out. That’s exactly backwards — the scientific quest to solve the world’s puzzles is one of the things that makes the story of our lives so interesting.

Of course there’s always much more to a good story than can be squeezed into a print magazine. So if you want the background scoop, see Cocktail Party Physics. Where, unfortunately, I’m (accurately) quoted as saying something in an old blog post that really isn’t true:

“Texas Hold ‘Em is so popular because it manages to accurately hit the mark between ‘enough information to devise a consistently winning strategy’ and ‘not enough information to do much more than guess.’ The charm in such games is that there is no perfect strategy, in the sense that there is no algorithm guaranteed to win in the long run against any other algorithm. The best poker players are able to use different algorithms against different opponents as the situation warrants.”

Two out of three sentences there are correct (which wouldn’t be such a bad average at a poker table, but is pretty lame in writing). The first sentence is right; what makes Hold ‘Em such a popular poker variant is that you know enough to do more than guess, but not enough to easily reduce the problem to a simple algorithm. But the second sentence is wrong, as written, at least under the perfectly reasonable reading that “win” includes “or tie.” One of John Nash’s major contributions to game theory was to prove, under reasonable assumptions, the existence of dominant strategies. Here, it’s not the opponents that are being dominated — it’s the other strategies a player might contemplate using. And “dominate” doesn’t mean “beat under any circumstances”; it just means “there is no alternative strategy that does better against every possible opponent strategy.” Since the rules of poker (integrated over all seats at the table etc.) are the same for every player, every player has the same dominant strategy — which means that there exists a strategy such that, if everyone used it, their expected returns would all be equal, and none of them could unilaterally change their strategy to improve on that expectation. Texas Hold ‘Em is sufficiently complex that the dominant strategy certainly isn’t known in closed form, but it does exist.

What I was clumsily aiming for in that sentence was the correct sentiment expressed in the last sentence. While a dominant strategy is in some sense “least bad” against the complete set of possible opponent’s strategies, it’s certainly not guaranteed to be the best against every specific opponent. If you know that your opponent deviates from dominant strategy in some particular way (not folding enough to re-raises pre-flop, for example), you will make the most money by choosing to deviate from dominant strategy yourself, in such a way as to take advantage of your opponent’s weakness. That’s the idea behind exploitative strategies, as advocated by Chris Ferguson in Jennifer’s blog post. Good poker is all about being exploitative. Any surprise that it’s a popular game among politicians?

Premiering tonight on SyFy. I trust no more needs be said.

There is something communal and primal about Zozobra. It feels purifying and freeing; the sorrows of the city have been dispelled. And I can bike to it from my house, which is a lot more convenient than Black Rock City. It is uniquely Santa Fe.

And yes there is a video record of the whole event! (And other Discover videos.)

The rough idea was to point out examples of good and bad science in science fiction on movies and TV. Phil scored the best example of bad science, finding a brief clip from Armageddon where Bruce Willis is doing delicate work on the surface of an asteroid — in the rain. Jaime and Zack, who actually work in Hollywood, wisely foresaw the pitfalls of holding up someone else’s stuff as an example of badness, and graciously both chose examples from their own work. Sometimes the science must take a backseat to the story.

But not usually. In my own presentation I tried to move beyond the model of scientist as copy-editor, running through stories and films looking for violations of the laws of physics, wagging the finger of shame with ill-concealed glee. I think scientists should take a more creative role, helping fiction writers to develop consistent rules for their fictional worlds and extrapolating the consequences of those worlds, even if those rules are not the rules of our real universe. We should be more than scolds.

Update: since the two clips I showed were apparently missing from the video, I’m linking to them here. The first was a forward-looking philosophy of the proper relationship between science and narrative, and the second was an example of carefully exploring the logical consequences of an imaginary world.

First is a New York Times interview with me. It’s very short, but we cover a lot of ground — science education, time travel, entropy, the movies, and my love life. Such plenitude of topics in a tiny piece will necessarily lead to compression, and Jerry Coyne is already complaining that I give short shrift to the complicated reality of aging — and he’s right!

Second and more fun, in Wired I am on the other side of the interviewer’s table, talking to Lost creators Damon Lindelof and Carlton Cuse. How cool is that? That was a great time, as we chatted excitedly about time, narrative, wormholes, fate and determinism, the role of science in television, and so on. These guys have given an incredible amount of thought into their show at every level — the characters, the mythology, and what it all means. And they wanted to ask me questions about cosmology and how scientists think, which I’m always happy to talk about. I got hooked on the show only after participating in Lost University, but now Tuesdays at 9:00 p.m. is the high point of my week. Only a few more episodes to go — which means that people who haven’t seen it can finally order the complete DVD selection, which is really the way to see it. (Just note that Season Three drags a bit, especially near the beginning.)

And even if today weren’t April Fool’s, anyone who thinks there are real spoilers in this clip is looking for a slapdown of their own.

McGonigal makes some good points in this short video, especially about how dealing with things in a video-game environment — like failure, or social interactions — can be greatly helpful when one eventually has to deal with them in the real world. She also helped put together Urgent Evoke, a large-scale multiperson game where you collect achievements by performing world-saving tasks.

The kids these days, they love their gaming. So it makes sense to ask how that passion can be put to good use. Personally I’m fascinated by the prospects of using games to teach people science. Not just facts and features of the real world — although those are important — but the scientific method of hypothesis-testing and experiment. Games already feature exactly those features, of course; everyone who figures out the “laws of nature” in the game world is secretly doing science. It wouldn’t be that hard to tweak things here and there so that the techniques they were practicing connected more directly with science in the non-virtual reality.

Lost has always played with time and narrative — characters’ backstories were told through elaborate flashbacks, lending a richness of nuance to their behavior in the main story. But time travel as a plot device was established as a central theme during Season Five. One happy consequence was the invention of Lost University, through which fans could learn a little about physics and other real-world subjects underlying events in the show.

Naturally, scientifically-minded folks want to know: how respectable is the treatment of time travel, anyway? We are, as always, here to help. My short take: Lost is a TV fantasy, not a documentary, and it doesn’t try all that hard to conform to general relativity or the other known laws of physics. But happily, the most important of the Rules for Time Travelers is very much obeyed: there are no paradoxes. And more interestingly, the spirit of the rules is obeyed, and indeed put to good narrative effect. The potential for time-travel paradoxes helps illuminate issues of free will vs. predestination, a central theme of the show. And what more can you ask for in a time-travel story than that?

Details below the fold, full of spoilers. (Not for the upcoming season, of course.) See also discussions from io9, Popular Mechanics, and Sheril.

The way that time travel works in Lost can be analyzed on three separate levels: physics, logic, and metaphor. (Or by ignoring all these high-falutin’ ideas and just enjoying the show, but where’s the fun in that?)

Physics

Make no mistake: the point of Lost is not to present a realistic depiction of time travel according to the laws of physics as we know them (or ever expect to know them). As explained in Chapter Six of From Eternity to Here, a remarkable feature of Einstein’s general relativity is that it provides a context in which we can sensibly talk about the idea of traveling in time. Space and time are curved together, and the amount of time elapsed between two events is affected by motion and gravity. Traveling near the speed of light, or lingering in a powerful gravitational field, you will “move into the future faster” than someone floating freely in empty space.

It’s easy to imagine — likely impossible to construct, but easy to imagine — curvature so intense that you can hop in a space ship and come back before you left. One particularly evocative mechanism for dramatic spacetime curvature is a wormhole, a shortcut through spacetime through which one could easily reach tremendous distances or wildly separated times via a relatively short journey. But it would still be a journey, involving relatively conventional means of transport; no flashing lights, no dematerializing and popping into existence elsewhere or elsewhen.

The tremendous amounts of energy and spacetime curvature necessary to maintain a realistic wormhole don’t fit easily into the island milieu of Lost. So the show simply doesn’t bother with such details. Characters, not to mention the island itself, do indeed pop randomly from one time to another. Even more divorced from realism, Desmond and other characters have their consciousness travel through time (“temporal displacements”), appearing in their physical bodies with all the memories and feelings of their future selves. Neither Einstein nor anyone else suggests any way that could happen in the real world.

Which is fine; it’s a TV show, not a science documentary. It’s an invented world, not the real one. But the writers do nevertheless hint at a scientific basis for time travel within this invented world, one that borrows from real physics. I probably was not the only viewer to laugh during Season Three when one of the hated Others was shown deeply engrossed in A Brief History of Time. More directly, in one of the Dharma Initiative orientation videos “Edgar Halliwax” (Dr. Chang) explains that the island contains a pocket of exotic matter, perhaps sustained by the Casimir effect, which lets them conduct unique experiments in space and time. That’s all on the right track. Even though general relativity lets us talk about wormholes, under ordinary circumstances we wouldn’t expect them to be useful for purposes of time travel — even if a wormhole were created, it would collapse to a singularity before anyone could cross it. A hypothetical way out is to invoke exotic matter, which would have a negative energy density and prevent the wormhole from collapsing. And how can we get negative energies? Perhaps from the Casimir effect, which arises when materials alter the energy contained in quantum vacuum fluctuations. Again, it’s not a full-blown respectable and realistic theory of time travel; but I’m happy that the show nods in the direction of real ideas, which will hopefully inspire the occasional viewer to dig more deeply into them.

Logic

It’s much more important that time travel in Lost makes logical sense — it’s consistent and obeys rules, even if the rules are not those of the real world. Most fundamentally, you can’t go into the past and alter the future; there are no alternate histories or any such cheap ploys. Daniel Faraday says at one point, “What happened, happened”; Sawyer just says “What’s done is done.” Dr. Chang, confronted in the video above with a worker who jokes about going back and killing Hitler, reacts in anger: “Don’t be absurd. There are rules!”

And the main rule is that things happen in a unique way at every place in space and time. If we have good reason, based on memories or some other form of records, to think that events played out in a certain way, then that’s what they did. There’s no changing things, and more than we can imagine changing the past under ordinary circumstances; the past already happened. As far as I can tell, the events we’ve been shown conform very well to this principle. Of course, there are certainly mysteries, and we’ll have to see how those are resolved in the season to come.

There is one seeming exception to this rule: Desmond’s visions of future events. He can see something happen in the future, and then take some action to prevent it (at least for a while). But as long as we’re being sticklers, we have to admit that a vision of the future isn’t the same as having that future actually happen. There is no paradox; only one thing ever happens in the real world, it’s just not necessarily the thing Desmond sees in his vision. When Desmond shuttles information back and forth between the past and present, it doesn’t conform to our ordinary notions of causality, but there’s nothing inconsistent about the complete history through time. I’m inclined to grant this bit of poetic license in the cause of interesting storytelling, as it still respects the no-paradox rule.

Despite the importance of this rule, fictional invocations of time travel tend to violate it all the time. Most such stories are all about changing the past, acting as if there is some narrative “meta-time” with respect to which events unfold, independently of the good old time we measure with physical clocks. (Think of Back to the Future, where Michael J. Fox does something in the 50′s and conditions “immediately” change back in the present day — erggh.) Personally I find the restrictions of logic to ultimately provide a more satisfying story structure.

By the end of Season Five, Faraday has become convinced that you can alter time, and hatches a plan to donate a nuclear bomb in 1977 to ultimately prevent everything we’ve later seen happen on the island. Faraday is killed by his mother, Eloise Hawking, but Jack and the other survivors try to carry out the plan. The finale of Season Five ends with a bright flash of light. We don’t know exactly what this means — that’s what cliffhangers are all about — but presumably this is the “Incident” referred to in later Dharma Initiative videos. I hope so, anyway; after all this wonderfully consistent if complicated narrative, it would be a shame to throw out a universe and start all over again.

Metaphor

Why does time travel fascinate us, anyway? Why do we find it so interesting? Part of it is the interest in changing the past — all of us have things we’d like to do over. But part of it is the fear of predestination. We like to think that, while the past is set in stone, we can make choices about our future — we have free will. But if we are able to travel into the past, then our future is part of the time that already happened — so in fact we don’t have complete freedom of action. Whatever it is we do when we get to the past, it must ultimately be consistent with how we know that past ultimately evolved into the present. That seems a bit irksome, even if it does respect the laws of physics.

This is where I think Lost really shines. One of the major themes of the show is destiny vs. free will, as embodied in the characters of Locke and Jack. Are there places where we are “meant” to be, or can we choose our paths for ourselves?

Well, there’s a balance. I can choose to turn right or left at a fork in the road, but I can’t choose to simply float into the air — there are the laws of physics to be obeyed. Lost uses the device of time travel to play with this tension — we think certain things are destined to happen, but we don’t know how. The logical restrictions of time travel are used as metaphors for the competition between predestination and choice.

A great example is the idea of “course corrections,” explained to Desmond by Eloise Hawking. Even if you see the future and try to prevent it, ultimately the designated fate is going to come to pass, perhaps in a different way (as with Charlie’s death). As a physicist this originally annoyed me, as that’s not how the laws of nature work — things happen or they don’t, but they’re not teleological, working through multiple channels to fulfill some crudely-specified goal.

But taking off my physicist’s cap and thinking more as a storyteller, I came to really appreciate this conceit as an interesting metaphor for how we try to think about fate. Determinism and the laws of physics are not the point; it’s simply that certain kinds of conditions pretty much inevitably result in certain kinds of outcomes. (Ever had two friends get together, and you knew from the start that it wasn’t going to last?) In our human lives, the rigid inevitability of the underlying physical laws isn’t very relevant to figuring out what’s going to happen next, but there is still some degree of predictability. The battle of destiny vs. free will isn’t one that has a winner and a loser; we are both constrained by circumstances, and free to make choices within that framework. That’s what makes life interesting.

Ultimately the idea of free will is tied to the arrow of time. Given perfect information about the present, in principle we could predict both the past and the future, without any wriggle room. But we don’t have perfect information. Because of the low entropy boundary condition in the past, we can nevertheless reconstruct what already happened with a certain amount of reliability; that’s why we think the past is unchangeable. But the future has no such boundary condition, and many possibilities are open. Otherwise I would tell you what’s going to happen over the next eighteen episodes of Lost.