SPEAKER_1: Welcome to StarTalk, your place in the universe where science and pop culture collide.
SPEAKER_1: StarTalk begins right now.
SPEAKER_1: This is StarTalk.
SPEAKER_1: I'm your host, Neil deGrasse Tyson, your personal astrophysicist, and I also serve as director of New York City's Hayden Planetarium.
SPEAKER_1: Today is the second hour of our sci-fi movie show, and I'm joined by my comedian co-host, Leanne Lord.
SPEAKER_1: I'm also happy to welcome back the bad astronomer, Phil Plait.
SPEAKER_1: The topic today is time travel.
SPEAKER_1: So let's just talk about time travel in the world of science.
SPEAKER_1: So what can you bring to the table?
SPEAKER_2: Well, it depends on what you mean by time travel.
SPEAKER_2: I mean, traveling into the future is...
SPEAKER_1: What do you mean, it depends on what you mean?
SPEAKER_1: Well...
SPEAKER_1: Which word did you not understand in that sentence?
SPEAKER_2: Well, there's a positive and negative, right?
SPEAKER_2: We all travel in time.
SPEAKER_2: We're going forward, you know, a minute every 60 seconds.
SPEAKER_2: So we're going into the future, like it or not, you're going to see it.
SPEAKER_1: But we're trapped in the present as we move to the future.
SPEAKER_2: Yeah, but when you said that, it was the present, but now it's the past.
SPEAKER_1: Ooh, spooky.
SPEAKER_3: You guys really shouldn't do Hallmark cards.
SPEAKER_3: I'm just saying.
SPEAKER_2: Well, but we're traveling into the future.
SPEAKER_2: And if you wanted to see what it's going to be like a hundred years from now, there are ways to do that.
SPEAKER_2: And if you want to see what things were like a hundred years in the past, there are kind of ways to do that.
SPEAKER_2: But if you want to see what the Earth was like a hundred years ago, we can talk about that too.
SPEAKER_1: So let's do it.
SPEAKER_2: All right.
SPEAKER_2: Well, traveling into the future, if you want to see the distant future, there are ways to do it.
SPEAKER_2: Suspended animation, for example, would work if there were some feasible way of doing it biologically.
SPEAKER_1: We don't know how to do that.
SPEAKER_1: It will slow down your bio-functions so that you basically age more slowly.
SPEAKER_1: This is a common way in sci-fi movies decades ago where they go on long trips and they put you in some kind of suspended animation.
SPEAKER_2: Right.
SPEAKER_2: It takes a hundred years to get from here to there, so you freeze the people and they can wake up when they get to their destination.
SPEAKER_2: We don't know how to do that.
SPEAKER_2: You freeze somebody, they're frozen.
SPEAKER_1: I'm told Walt Disney knows how to do it.
SPEAKER_2: I suppose we could send his head to Alpha Centauri and see what happens.
SPEAKER_3: Bad freezer burn, fellas.
SPEAKER_2: That's true.
SPEAKER_2: You've got something on your nose.
SPEAKER_2: Oh, sorry, frostbite over your entire brain.
SPEAKER_2: All right.
SPEAKER_2: But that is possibly one way.
SPEAKER_2: Another way would be to travel very quickly.
SPEAKER_2: And according to Einstein's...
SPEAKER_2: Good old Albert.
SPEAKER_2: Relativity.
SPEAKER_2: Somebody who's moving very rapidly relative to someone on Earth would age more slowly.
SPEAKER_2: And so if you were to get in a spaceship and move very close to the speed of light, you could literally travel across the galaxy.
SPEAKER_2: And somebody on Earth would experience 100,000 years elapsing, while you might only experience a few months elapsing.
SPEAKER_2: And that is time travel into the future because if you went to the star, you poked around, planted your flag, turn around, came back, 200,000 years would have elapsed on Earth.
SPEAKER_2: And you would have only experienced a short...
SPEAKER_1: A couple of months for you.
SPEAKER_2: A fraction of that.
SPEAKER_1: But by then, everyone would have forgotten about you.
SPEAKER_2: Ooh, yeah.
SPEAKER_2: And yeah, no taxes.
SPEAKER_2: There may be some advantages to this.
SPEAKER_2: But the problem with that is we have no clue how to go that fast.
SPEAKER_1: No, I bet everyone who wants to travel to the future wants to be able to come back to the present.
SPEAKER_1: That's my sense of it.
SPEAKER_2: So really, yeah, the honest definition of time travel is being able to travel backwards in time.
SPEAKER_1: Or just treat the timeline as an accessible dimension.
SPEAKER_1: Like a road.
SPEAKER_2: You can get off and get back on some other place or go back to where you were as many times as you want.
SPEAKER_2: Cloverleaf.
SPEAKER_2: A chronological cloverleaf.
SPEAKER_2: Write that down.
SPEAKER_2: I'm going to patent that and make that into a URL.
SPEAKER_2: I don't know how I feel about that.
SPEAKER_2: Traveling backwards in time, the thing is if you go back in time, the usual paradox is I make a time machine, I go back in time, I kill my grandfather before he meets my grandmother, and I'm never born.
SPEAKER_1: And if you're never born, you couldn't have gone back in time to prevent them from meeting each other.
SPEAKER_2: Exactly, it's a paradox.
SPEAKER_2: It's impossible to happen.
SPEAKER_2: I always wonder about that.
SPEAKER_2: Why do they always say grandfather?
SPEAKER_2: Why don't I just go back in time and kill my father?
SPEAKER_2: I liked my father, I wouldn't have any desire to do this.
SPEAKER_1: That's why they don't portray that in film.
SPEAKER_1: Maybe.
SPEAKER_1: It's a little more diabolical to kill your parents.
SPEAKER_2: Oedipus time rex.
SPEAKER_1: Plus, why even kill them?
SPEAKER_1: All you have to do is prevent them from meeting.
SPEAKER_1: That's right.
SPEAKER_2: If they don't meet at the Enchantment Under the Sea prom dance, then they'll never meet.
SPEAKER_1: Put them on different trains, then they don't meet.
SPEAKER_2: Exactly.
SPEAKER_1: Give one of them bad breath before they encounter.
SPEAKER_2: There are other paradoxes involved.
SPEAKER_2: That's sort of the canonical one, the one that everybody always brings up.
SPEAKER_2: There are other ones.
SPEAKER_2: What happens to the atoms that you're made of in the future and you bring them back into the past, they're the same atoms existing in two different places at the same time.
SPEAKER_1: Because presumably your present still exists in the present.
SPEAKER_2: Yes.
SPEAKER_2: So if everybody in the future went back in time, suddenly there's more people, there's more mass in the universe than there was.
SPEAKER_1: At that time.
SPEAKER_2: Yeah, at that time.
SPEAKER_2: Maybe averaged over the age of the universe.
SPEAKER_1: You know, it's been said that in the future they have actually invented a time machine and the most curious historical event that has piqued people's interest is the sinking of the Titanic.
SPEAKER_1: So they all went back to the Titanic to see it sink and that's why it sank.
SPEAKER_1: This was my idea for a short story.
SPEAKER_2: In fact, the reason the Titanic sank is because nobody knew how to steer the ship because they were all time travelers from the future.
SPEAKER_2: It's like they're all standing here like, oh, there's an iceberg, we should do something.
SPEAKER_2: And they're like, I don't know how to do something.
SPEAKER_2: All I know is I can pilot a rocket ship, but I don't know how to do a cruise liner.
SPEAKER_1: Right, yeah, a steamship cruise liner, yeah.
SPEAKER_2: Yeah, I always liked that idea.
SPEAKER_1: So maybe actual events that have happened in the past have already been influenced by time travelers.
SPEAKER_2: Right, and so the other idea is that if you travel backwards in the past, the time is fixed and it's not like a river flowing.
SPEAKER_2: It's more like a landscape.
SPEAKER_2: And you can move from one place to the other, but it's fixed.
SPEAKER_2: If you go back in time and do something, then that happened always.
SPEAKER_2: So you can't go back and kill your grandfather.
SPEAKER_2: All you can do is whatever random things you're doing, but no matter what you do, your grandfather and grandmother are going to meet.
SPEAKER_2: They're going to have one of your parents, and they're going to have you.
SPEAKER_2: You cannot change the past.
SPEAKER_3: So you're saying there's no way I'm going to change my SAT score.
SPEAKER_2: That's right.
SPEAKER_2: If you go back in time to change your SAT score, whatever you do will ensure that you got the SAT score you did when you were a kid.
SPEAKER_1: Right.
SPEAKER_1: So this is...
SPEAKER_1: Right.
SPEAKER_2: I love thinking about this, because it sounds so confusing, but when you think about it, it makes perfect sense.
SPEAKER_2: No matter what you do, what's going to happen is what's going to happen.
SPEAKER_1: Okay, but that's a hypothesis.
SPEAKER_1: What I'm asking you for now is, what science do you know that allows backward time travel?
SPEAKER_1: I don't really know of any.
SPEAKER_2: I've heard some theoretical things and some really crazy physics involving infinitely long cylinders that are rotating near the speed of light and all kinds of crazy stuff like that.
SPEAKER_1: And you take a loop around it that will revisit your world line earlier than when you left?
SPEAKER_2: Yeah, it's like doubling back on your own timeline.
SPEAKER_2: And I'll be honest, I don't understand that kind of physics.
SPEAKER_2: That's way over my head.
SPEAKER_2: Or possibly going around a black hole and there are ways of going through it and coming back at a different point in space and time.
SPEAKER_2: Space and time are related, and in a black hole, they kind of swap places.
SPEAKER_1: And in a few months, we'll have lost all capacity to go back into orbit the Earth.
SPEAKER_1: So conversations about orbiting black holes is not only science fiction, it's like something completely out of reach.
SPEAKER_2: Yeah, it seems a little far-fetched right now.
SPEAKER_1: All right, so what you're suggesting is even though there's no real accessible way to go backwards in time, it doesn't prevent anyone from thinking about the consequences of it.
SPEAKER_2: Sure thing.
SPEAKER_2: And I like thinking about it.
SPEAKER_2: It's a fun mental exercise.
SPEAKER_1: A fun mental exercise.
SPEAKER_1: And of course, many films have addressed this, which we'll get to later in this hour.
SPEAKER_1: But until then, let's talk about going into the future.
SPEAKER_1: Einstein, with his relativity, demonstrates that this is possible.
SPEAKER_1: People freaked out.
SPEAKER_1: They said, no, you can't travel into the future.
SPEAKER_1: I mean, so relativity had some naysayers at the time.
SPEAKER_1: This we're now talking 100 years ago, 1905, right?
SPEAKER_2: Well, time keeps on slipping, slipping, slipping into the future, I believe.
SPEAKER_2: So fly like an eagle.
SPEAKER_2: Oh, is that what that is?
SPEAKER_2: Oh, I'm sorry.
SPEAKER_2: I thought that was, I thought that was Thoreau.
SPEAKER_2: Yeah, and sure, even when Einstein came out with his ideas, people were having a problem with it.
SPEAKER_2: But come on, it's weird that time is fluid.
SPEAKER_2: Like, you can, you all know that, you know, waiting for a watch pot never boils, and if you're bored, time seems to take longer.
SPEAKER_2: But that's just perception.
SPEAKER_2: Einstein was talking about a physical change in the way time elapses.
SPEAKER_2: And if you're moving very quickly, your time slows down relative, that's where the relativity word comes from, someone who's not moving.
SPEAKER_2: Or if you're in a deep gravity field, your time seems to move slower than somebody outside.
SPEAKER_1: So an important distinction there is, I think earlier on people were saying, well, if it's just my perception that time has slowed down, then a watch shouldn't know the difference, if it's just my biology.
SPEAKER_1: But in fact, it's everything.
SPEAKER_1: It is the fabric of space and time that is providing this ability or this feature.
SPEAKER_2: That's right.
SPEAKER_2: And when I talk to people about this, and I'm sure as you do as well, when you do your public outreach, you really have to say, no, it's not just that you think time is slowing down.
SPEAKER_2: Your watch is physically ticking at a different rate than a different one.
SPEAKER_1: And so too is your metabolism, the rate your atoms vibrate.
SPEAKER_2: Everything, yes.
SPEAKER_2: Subatomic particles are decaying and doing whatever it is they do on a daily basis, when behind closed doors, they're doing that at a different rate.
SPEAKER_2: It really is.
SPEAKER_2: But it can speed up or slow down, and so there's probably some prurient interest in this.
SPEAKER_2: But in general, you know, their time is different.
SPEAKER_1: Now, over earlier, before the show, you were talking about GPS and how that needs relativistic correction.
SPEAKER_1: Tell us about that.
SPEAKER_2: This is something I like.
SPEAKER_2: You must get email.
SPEAKER_2: I get email.
SPEAKER_2: Oddly enough, when you go out there and try to talk about science and correct people's misunderstandings of science, you get email from people who are, I have this theory.
SPEAKER_2: And I constantly get people...
SPEAKER_3: I'm sorry.
SPEAKER_3: I'm very sorry.
SPEAKER_3: I have questions.
SPEAKER_2: Please stop emailing me, Leanna.
SPEAKER_2: I'll get people saying, I have a theory that overthrows relativity.
SPEAKER_2: No, you don't.
SPEAKER_2: You don't.
SPEAKER_2: Relativity is one of the best tested ideas of all time.
SPEAKER_2: And in fact, the one thing I tell people is, everybody uses a GPS these days.
SPEAKER_1: In some way or another.
SPEAKER_2: To your phone, to your car, whatever.
SPEAKER_2: And GPS has to account for relativity.
SPEAKER_2: The satellites that are orbiting the Earth that are used for global positioning are actually high enough up that the gravity they feel from the Earth is actually a little bit different than the gravity we feel here at the surface.
SPEAKER_2: And that makes their clocks tick a little bit faster.
SPEAKER_1: As specified by relativity.
SPEAKER_2: Yes.
SPEAKER_2: And relativity says, bam, this is what it is.
SPEAKER_1: So relativity says if you're deep in a gravity well, as we are down on the surface of the Earth, gravity will tick more slowly than if you're at a lesser gravity high up.
SPEAKER_2: That's right.
SPEAKER_1: And so these are orbiting high up, so their clocks are ticking at a different rate, yet they're trying to tell you what time it is.
SPEAKER_2: Oh, but wait a moment, Neil, because it gets worse than it.
SPEAKER_1: But wait, there's more.
SPEAKER_2: Wait a moment.
SPEAKER_2: This moment will stretch out relativistically.
SPEAKER_2: In fact, Einstein also said that if you're moving relative to somebody else at a high velocity, your clocks will slow down.
SPEAKER_2: And these satellites are orbiting the Earth at 15,000, 18,000, whatever it is, miles per hour.
SPEAKER_2: They're moving very quickly.
SPEAKER_1: So they've got two strikes against them.
SPEAKER_2: So their clocks are faster than ours a little bit because they're experiencing lower gravity, but they're moving so rapidly, their clocks are actually moving slower than ours.
SPEAKER_2: When you take these two effects into account...
SPEAKER_1: What's the net effect?
SPEAKER_2: The net effect is that their clocks are ticking more slowly.
SPEAKER_2: You have to account for both of these to get it right.
SPEAKER_2: And since global positioning satellites have to know where their position is and where your position is to figure out the position, the P in GPS, if you don't account for relativity, and they use clocks to do this...
SPEAKER_1: I like that the P in GPS, that's good.
SPEAKER_2: That's right.
SPEAKER_2: It doesn't stand for fill or plate.
SPEAKER_2: It's actually position.
SPEAKER_2: If you don't account for these relativistic effects, your GPS would be off by some large amount.
SPEAKER_2: It's hundreds of yards or a fraction of a mile every single day.
SPEAKER_1: And that would accumulate, presumably.
SPEAKER_2: Yes, it would.
SPEAKER_2: And so the fact that your GPS can nail you down to a few yards wherever you're standing means that relativity is correct.
SPEAKER_1: So the people that say relativity is wrong, they just have no...
SPEAKER_1: yet they're happy to use their GPS.
SPEAKER_2: Yes, and so they're absolutely wrong.
SPEAKER_2: There's no relative here.
SPEAKER_2: They're wrong.
SPEAKER_1: They're wrong, not...
SPEAKER_1: right.
SPEAKER_1: So...
SPEAKER_1: Turn right ahead.
SPEAKER_1: Relatively not only works on paper, it works in space.
SPEAKER_2: Yes, and there are other things too.
SPEAKER_2: We see subatomic particles with very short lifetimes that are created at the top of the atmosphere when cosmic rays hit our air.
SPEAKER_2: And these subatomic particles we detect on the ground could not possibly reach the ground in the amount of time.
SPEAKER_2: So we know that they're moving so quickly that their clocks have slowed down, and they have the lifetime to make it.
SPEAKER_1: So it affects obviously not only wristwatches and biological metabolism, it's affecting the rate at which particles decay.
SPEAKER_2: The very fabric of the universe is relativistic.
SPEAKER_1: They even know about the relativity.
SPEAKER_2: That's exactly right.
SPEAKER_2: That's deep.
SPEAKER_1: That stat is so deep.
SPEAKER_1: When we come back, we're going to take a tour of all the best time travel movies there are, and see how well they do.
SPEAKER_1: This is StarTalk Radio.
SPEAKER_1: Bye This is StarTalk Radio, welcome back.
SPEAKER_1: So, what do you think of Planet of the Apes?
SPEAKER_2: I love that movie, the original what Charlton has to do.
SPEAKER_1: Yeah, and they had people in suspended animation, as we discussed in the first segment, because they didn't know how long, you don't want to use up your resources.
SPEAKER_1: And so, and then some of them died, I think, when they landed, is that right?
SPEAKER_2: There was a woman on board who dies in suspended animation.
SPEAKER_2: One of his fellow astronauts gets shot, and then another one gets shot and stuffed and put into a museum.
SPEAKER_1: I remember that, and you see the cotton in his eyes, yeah.
SPEAKER_2: Yeah, that was so grim.
SPEAKER_1: Well, that's what they did, because they're the damn dirty apes.
SPEAKER_1: So tell me about the time travel in that.
SPEAKER_1: Was it, comment on its accuracy, what do you think?
SPEAKER_2: It was fine, they're traveling to a different star, so they're moving very rapidly.
SPEAKER_1: So they must have gone in some loop, because they landed back on Earth, but didn't know it.
SPEAKER_2: That's not another planet.
SPEAKER_1: Let's make this clear.
SPEAKER_1: This is not some parallel planet that had a different evolutionary track.
SPEAKER_1: This is Earth that he comes back to in the future.
SPEAKER_1: And what humans evolve back into apes?
SPEAKER_1: Does your data support this, that humans are evolving back to apes?
SPEAKER_1: Back to hairy apes, I think.
SPEAKER_3: I'm actually not convinced of what you just said.
SPEAKER_3: How do we know it's not an alternate developmental track?
SPEAKER_3: How do we know that?
SPEAKER_1: Oh, yeah, yeah.
SPEAKER_1: Phil, yeah.
SPEAKER_2: There are some lines in the movie.
SPEAKER_2: So we know it's the Earth in the end, because he's at the Statue of Liberty.
SPEAKER_2: And so there are some other things that indicate it's Earth.
SPEAKER_2: There's some gotcha lines in it when they're on a raft and they're going down the river and they're trying to figure out where they are.
SPEAKER_2: One of them looks up at the sun and the sky and says, it's a little too yellow.
SPEAKER_2: Do you think it's Bellatrix?
SPEAKER_2: Which is a real star in Orion.
SPEAKER_2: And they're sort of misleading you, making you think they're on a different planet.
SPEAKER_2: And in the sequels in Beneath the Planet of the Apes and Battle for the Planet of the Apes and Apes of the Planet, I don't know, there was like five sequels.
SPEAKER_2: They actually establish how one of the apes comes back in time.
SPEAKER_2: And that's where you have to assume there's time travel.
SPEAKER_2: The ape goes back in time and becomes the first ape that can talk and then leads the revolution, which becomes the Planet of the Apes.
SPEAKER_1: Oh, so what you're saying is that the entire premise of that movie required backwards time travel.
SPEAKER_2: I don't think in the first movie it does.
SPEAKER_1: That they thought that threat.
SPEAKER_2: I don't think so.
SPEAKER_2: And in the original book, it's actually-
SPEAKER_1: Well, you read the books too.
SPEAKER_2: Yeah, it's actually a decent book.
SPEAKER_2: He's a Renaissance man.
SPEAKER_2: Really, yes, I still read.
SPEAKER_2: But then this was like 20 years ago when I still read.
SPEAKER_2: Now I prefer to just sleep.
SPEAKER_2: But I believe they go to another planet and it's a parallel evolution and they come back to Earth.
SPEAKER_2: And the big twist is, apes have taken over during the time they were gone.
SPEAKER_1: Right, right.
SPEAKER_2: Maybe not as much impactful as pounding the sand and screaming at the Statue of Liberty, but still, it's a decent book.
SPEAKER_1: Okay, and so, now how about Groundhog Day?
SPEAKER_1: That's a fun one.
SPEAKER_1: That's the time travel I think we all wish we could be part of, because you get to slightly change what happens.
SPEAKER_2: Speak for yourself.
SPEAKER_1: You get to change the past.
SPEAKER_1: He wakes up every morning, relives the day, but he has a memory of what happened the last time.
SPEAKER_1: What do you think of that?
SPEAKER_2: It's an interesting premise.
SPEAKER_2: It's never really explained.
SPEAKER_2: It's clearly not the Groundhog itself because he kills the Groundhog in a, what, he steals a truck and dives over the edge of a quarry and he still wakes up listening to Sonny and Cher.
SPEAKER_2: And you know, if you want to wake up to, I've got you, babe.
SPEAKER_1: You remember this much about the movie.
SPEAKER_2: Oh yeah, yeah.
SPEAKER_2: It's a good flick.
SPEAKER_1: Phil, this is scary.
SPEAKER_2: Well, you know, his name is Phil in the movie.
SPEAKER_2: And so, the Groundhog, both.
SPEAKER_2: And so everybody teases him about that.
SPEAKER_1: I thought Phil was his last name.
SPEAKER_1: Punxsutawney Phil.
SPEAKER_2: Punxsutawney Phil.
SPEAKER_1: Yeah, okay.
SPEAKER_2: But his name is Phil, anybody, okay, we need to.
SPEAKER_3: Okay, now is when the RX-8's tweeting.
SPEAKER_2: It doesn't matter.
SPEAKER_1: We got our engineers tweeting there.
SPEAKER_2: But.
SPEAKER_1: I mean, Googling, yes.
SPEAKER_2: It was kind of a cool idea, and you don't really ever find out how long he was in there, but he was in there long enough to be able to become an incredible piano player at the end of the movie.
SPEAKER_2: And I think there was an interview, was it Robert Zemeckis or John Landis, who directed this movie?
SPEAKER_2: Well, whoever.
SPEAKER_2: There was an interview with him saying he was actually trapped in there for years, maybe even hundreds of years.
SPEAKER_1: Long enough to be able to acquire that expertise?
SPEAKER_2: Yeah.
SPEAKER_1: Okay.
SPEAKER_2: And to me, that would be the ultimate torture, to be able to be trapped in one place like that and have to live that over and over again.
SPEAKER_2: It would make me crazy.
SPEAKER_1: How about Superman?
SPEAKER_2: Uh-huh.
SPEAKER_1: The original Superman, the movie.
SPEAKER_2: Okay.
SPEAKER_1: The one where you will believe man can fly.
SPEAKER_2: Yeah, Christopher Reeve.
SPEAKER_2: Okay, I love this movie.
SPEAKER_2: 1970, whatever.
SPEAKER_2: It's still one of John Reeve's best soundtracks.
SPEAKER_2: I just think it's one of the best superhero movies.
SPEAKER_2: It just takes itself exactly the right amount of seriously.
SPEAKER_1: Wait, Superman 2 was a little better, but we're referring specifically to the time.
SPEAKER_2: The time travel.
SPEAKER_1: The time reversal.
SPEAKER_2: I just want to get that out there that I like this movie.
SPEAKER_2: He flies around the earth, and somehow the earth spins the other way.
SPEAKER_1: He flies around the earth backwards from the rotation.
SPEAKER_2: And I think there was a little bit of confusion there.
SPEAKER_2: I think that he was supposed to be traveling so close to the speed of light that he was reversing time.
SPEAKER_2: But it looks like he's flying around the earth so quickly that the earth somehow gets dragged backwards and spins backwards as if you're just spinning the earth backwards would spin backwards time.
SPEAKER_1: Leaving everyone to think, yeah, if you just turn the earth backwards, the time would reverse.
SPEAKER_2: Yeah, and why doesn't he reverse time a couple of days so he has more time to fix things?
SPEAKER_2: And let me tell you something, the whole reason this thing happens is because Lex Luthor is shooting two missiles in opposite directions.
SPEAKER_2: And he promises Ms.
SPEAKER_2: Tessmacher, and yes, believe me, I know this movie, that he's gonna stop the missile heading towards New Jersey.
SPEAKER_1: Hackensack, where her mother lives.
SPEAKER_2: Where her mother lives, that's exactly right.
SPEAKER_2: And so he has to stop that one.
SPEAKER_2: He can't stop the one that hits the San Andreas Fault.
SPEAKER_2: That's why Lois Lane gets killed, and he has to make the earth go backwards.
SPEAKER_2: He can't catch up to a missile, but he can fly around the earth fast enough to make it spin backwards.
SPEAKER_1: Hello, hello.
SPEAKER_1: Yeah, that's crazy.
SPEAKER_1: That's crazy.
SPEAKER_1: Plus at the time, I had a girlfriend, and we saw the movie together, and he starts flying backwards and reverses time, and she turns to me and says, can he really do that?
SPEAKER_1: And I said, why didn't you ask me earlier whether a man in blue pantyhose can fly?
SPEAKER_1: Why is this the first issue that you have with the physics of the film?
SPEAKER_1: People have different thresholds.
SPEAKER_2: And if you ever watch Big Bang Theory on TV, in the first episode, they go through this.
SPEAKER_1: I did not see the first episode.
SPEAKER_1: I have to go back to the archives.
SPEAKER_2: They're talking to somebody about this and saying, can Superman fly or does he just jump?
SPEAKER_2: And there's this whole thing about it.
SPEAKER_2: She says, oh, well, people can't really fly.
SPEAKER_2: And one of the nerds actually says, oh no, let's assume that.
SPEAKER_2: It's like the first thing that a science nerd would actually say, no, blah, blah, blah.
SPEAKER_2: And so they actually, they just sweep right past that.
SPEAKER_2: I love that scene.
SPEAKER_2: It's very funny.
SPEAKER_1: Okay, so you're saying, obviously he can't do that, but he's Superman, so why not let him do it in the, it's Superman physics.
SPEAKER_1: It's not real physics.
SPEAKER_2: He can fly.
SPEAKER_2: He's invulnerable.
SPEAKER_2: Is there a degree in this?
SPEAKER_2: Is that what makes it so that when he puts on a pair of glasses, nobody knows that he's Superman?
SPEAKER_1: Yeah, that's how they, that's, you know.
SPEAKER_1: So how about Star Trek IV, the voyage home?
SPEAKER_2: Voyage home with the whales.
SPEAKER_1: That's had some time travel back to our present of the day.
SPEAKER_1: It was Save the Whales.
SPEAKER_1: That was the subtitle for that one.
SPEAKER_2: And Star Trek did this in the series a few times.
SPEAKER_2: They've done this in the movies.
SPEAKER_2: You know, it's, in the series, they established that if you warp around the sun, it'll somehow make you go back in time.
SPEAKER_2: And since that's moving, since moving faster than light, as far as we know, is impossible anyway, and who knows how this physics works.
SPEAKER_2: Sure, yes, warping around the sun can make you go back in time.
SPEAKER_1: Wait a minute, but if-
SPEAKER_2: But why not?
SPEAKER_1: But we all know that tachyons, which exist faster than light, do move backwards in time.
SPEAKER_2: So if they're real, though.
SPEAKER_1: But if they did exist, they would move backwards in time.
SPEAKER_2: Because they're moving faster than light.
SPEAKER_3: It's a lot of ifs.
SPEAKER_2: And if Neil is making sense, and-
SPEAKER_1: No, no, but they're good ifs.
SPEAKER_1: These ifs are better than other ifs.
SPEAKER_2: I have some buts for your ifs.
SPEAKER_3: And then some thens.
SPEAKER_1: So the point is, in Einstein's equations, if you put in faster than light velocity, you get backwards time travel.
SPEAKER_1: So you hypothesize a particle that would do this.
SPEAKER_1: So if you are in a sci-fi story and you go faster than light, as they're doing all the time with their warp drives, they can in principle go backwards in time, like the tachyons can.
SPEAKER_2: I will have to grant that.
SPEAKER_2: I never took a class in general on relativity in grad school, so actually I don't know.
SPEAKER_2: So you could be making this up, and I would-
SPEAKER_1: Sure!
SPEAKER_2: Yes, Neil, of course!
SPEAKER_2: I think it's patently obvious, even the most dim-witted observer, that of course you're correct.
SPEAKER_3: But doesn't this only work if Scotty is your engineer?
SPEAKER_2: Yes.
SPEAKER_3: Okay.
SPEAKER_1: And only if occasionally the engines can't take it.
SPEAKER_2: Yes, that's right.
SPEAKER_1: So what did you think of the scene where he helps the engineer on his Mac Plus, whatever the computer was at the time, he helps the engineer invent transparent aluminum, and then they worry that he affected time in the past, which of course their very existence back then is doing this, right, they're affecting events.
SPEAKER_1: And then he said, well, how do you know he's not the guy who invented it in the first place?
SPEAKER_2: Right, and then McCoy leans over and says that to Scotty, and he's like, oh.
SPEAKER_2: So yeah, I mean, if you're going to explain a big time travel paradox, that's a great way to do it.
SPEAKER_2: Right.
SPEAKER_2: You shuffle it right under the rug.
SPEAKER_2: I thought that was hysterical.
SPEAKER_2: And here's Scotty who's picking up a mouse because he doesn't know that it's not a...
SPEAKER_1: The computer mouse.
SPEAKER_2: Yeah, a microphone to talk to it.
SPEAKER_2: And yet he can seem to program in the Mac OS operating system, you know, from 1980 whatever it was.
SPEAKER_3: But that's an ad about how simple it is.
SPEAKER_3: It wasn't Windows.
SPEAKER_1: Oh, there it is.
SPEAKER_2: It just works.
SPEAKER_1: So another...
SPEAKER_1: One of my favorite piece of that film was when McCoy, the doctor, McCoy, is walking through the hospital just healing everybody.
SPEAKER_1: Yeah, dialysis.
SPEAKER_2: Doctor gave me a pill and I grew a new kidney.
SPEAKER_1: A new kidney.
SPEAKER_1: And I'm thinking, you know, maybe that's kind of cool.
SPEAKER_1: We do some of that today compared with medicine from 200 years ago.
SPEAKER_1: It looks like...
SPEAKER_1: It would look like magic today.
SPEAKER_2: I have to wonder what medicine is going to be like.
SPEAKER_2: And I would assume a lot of it is going to be just even cutting around a lot of the problems we have today.
SPEAKER_2: They won't even have to worry about stuff like that.
SPEAKER_1: So we all look forward to Medicine of the Future for sure.
SPEAKER_1: One of my favorite of the benchmark movies was Time Machine itself, HG.
SPEAKER_1: Wells, done a few times in film.
SPEAKER_1: What I found most interesting about it was his loved one died.
SPEAKER_1: And his love interest died, the main character's love interest, and he went back to keep trying to save her.
SPEAKER_1: And everything he tried to do to save her would get her killed.
SPEAKER_1: And so he recognized that that was a fundamental part of the timeline that he could not change.
SPEAKER_2: Oh, so this is in the remake, the recent remake.
SPEAKER_1: The remake, yes, yes, that was captured.
SPEAKER_2: Although honestly, he went back once and tried and it didn't work, and then he's like, oh, well that's it.
SPEAKER_2: Really?
SPEAKER_2: You can't show at least one other effort?
SPEAKER_1: When we come back, we're going to talk about The Terminator.
SPEAKER_1: We'll see you after the break.
SPEAKER_1: We're back on StarTalk Radio with Phil Plait, the bad astronomer, and comedian Leanne Lord.
SPEAKER_1: We're talking about time travel in movies, and just before the break, we mentioned The Terminator, but I'm gonna save that for a little later.
SPEAKER_1: Let's go into just a campy, fun movie, Bill and Ted's Excellent Adventure.
SPEAKER_1: How could you not love that movie?
SPEAKER_2: I really liked it, I thought it was quite funny.
SPEAKER_1: I thought it was great.
SPEAKER_1: And any comments about the science of that?
SPEAKER_2: Well, in fact, if you take an umbrella, I can't believe that sentence actually came out of my mouth.
SPEAKER_2: If you take an umbrella and attach it to a telephone booth, and you happen to have George Carlin handy, time travel is in fact possible.
SPEAKER_2: I won't even mention that time traveling phone booths may have been done by Doctor Who first, but.
SPEAKER_1: And wasn't it a phone booth in Time Bandits or not?
SPEAKER_2: Oh my gosh, I don't remember.
SPEAKER_1: Yeah, I forgot that, maybe.
SPEAKER_1: Well, they had the map, but I don't remember.
SPEAKER_3: So is that why they've actually gotten rid of phone booths?
SPEAKER_1: People were moving around in time.
SPEAKER_1: Superman uses it to become Superman?
SPEAKER_1: I mean, phone booths, where would we have been without them in our story time?
SPEAKER_2: They're the Swiss Army knife.
SPEAKER_2: That's true.
SPEAKER_2: It's the Swiss Army knife of movie science.
SPEAKER_1: So what I liked about Bill and Ted was that they kept the personalities of these characters in the present.
SPEAKER_1: And so Beethoven went into the music shop in the mall, and Genghis Khan has got the baseball bat, and Joan of Arc is conducting the aerobics lesson.
SPEAKER_1: I just thought that it was kind of cool.
SPEAKER_1: It's what you'd want it to be if you could go back and bring historical figures into the present.
SPEAKER_2: There's a crucial scene when they need to get someplace and they need to get a car.
SPEAKER_2: I can't remember the exact details, but they're standing there talking and they're saying we have a time machine.
SPEAKER_2: We could go into the future or go into the past, get the keys to the car and leave them for us here.
SPEAKER_2: Well, where would we leave them?
SPEAKER_2: How about right here behind the sign?
SPEAKER_2: And they walk by the sign and there are the keys.
SPEAKER_2: I was like, we have to remember to do that later, dude.
SPEAKER_2: And they do.
SPEAKER_2: And it was like, I could not stop laughing in the theater watching.
SPEAKER_1: So it was brilliant, actually.
SPEAKER_2: Yeah, it was actually really, really well done, tightly scripted movie.
SPEAKER_1: They willed the keys to exist where they would look for them, but they had to remember to put them there when they went back in time.
SPEAKER_2: That's right.
SPEAKER_2: And I love that in movies and to mention Doctor Who again as well, it's a British time travel show.
SPEAKER_2: When they actually use time travel that way, when they say, I need to remember to go back in time and do this later.
SPEAKER_2: I just love stuff like that.
SPEAKER_2: It makes me giggle.
SPEAKER_1: So how about Terminator?
SPEAKER_2: Well, there you go.
SPEAKER_1: That's a tight movie.
SPEAKER_1: That's a tight movie, you gotta admit.
SPEAKER_2: You know, that movie came out.
SPEAKER_1: Wait, wait, first, geek off, geek off.
SPEAKER_2: Okay.
SPEAKER_1: Geek alert.
SPEAKER_1: Can you recite every one of Arnold's lines in that movie?
SPEAKER_1: There are only five of them.
SPEAKER_2: Really?
SPEAKER_1: Yes.
SPEAKER_2: Your clothes, give them to me.
SPEAKER_1: Good one, okay.
SPEAKER_1: Your clothes, give them to me.
SPEAKER_2: Good.
SPEAKER_1: Blank.
SPEAKER_1: Okay.
SPEAKER_1: You got another one?
SPEAKER_2: Blank off, blank hole.
SPEAKER_2: How about that?
SPEAKER_2: Or beep off, beep hole.
SPEAKER_2: Now that sounds even worse.
SPEAKER_2: That's actually quite dirty, I think.
SPEAKER_1: What does your address there?
SPEAKER_2: Give me your address there.
SPEAKER_1: Give me your address there.
SPEAKER_2: Give me your address there.
SPEAKER_1: Okay.
SPEAKER_2: Oh, gosh, what else does he say?
SPEAKER_2: I don't remember.
SPEAKER_1: I love the fact that he lands at Griffith Observatory and Planetarium in Los Angeles.
SPEAKER_2: Yeah, that's right.
SPEAKER_1: That's where he lands.
SPEAKER_3: Nice bit of product placement.
SPEAKER_2: Yeah, there you go.
SPEAKER_2: Um, your clothes can be used for, I can't remember anything else.
SPEAKER_3: So is Ostalavista Baby not in one?
SPEAKER_2: No, no.
SPEAKER_2: That's in the second one, okay?
SPEAKER_2: Yeah, the young John Connor teaches him to say that.
SPEAKER_3: Just testing you guys on your gig.
SPEAKER_2: Then I'll be Bach, when he leans over, I love that.
SPEAKER_2: And then the cop's just sitting there doing his stuff, and then the car crashes through.
SPEAKER_1: So tell me about some of the, what might be the signs of that.
SPEAKER_2: Well, you just have to kind of say, well, they invent time travel.
SPEAKER_2: Actually, the one beef is-
SPEAKER_1: Thank you, Phil.
SPEAKER_2: Thank you, yes.
SPEAKER_1: For coming from Colorado to New York to tell me this.
SPEAKER_2: Yeah, thank you.
SPEAKER_2: Thank you, and tip your waitress.
SPEAKER_2: In fact, the thing that kills me is, we've had this nuclear war, humans are on the run, we're about to be crushed, and yet somehow we have the wherewithal to invent time travel.
SPEAKER_2: Hey, maybe you should have built a bomb to blow up Skynet or something, but no, we'll work on time travel instead.
SPEAKER_3: Well, I thought, no, no, no, I thought the machines had worked on time travel, and we just sort of stole that because they sent the Terminator back, and then we sent Reese back to go after the Terminator.
SPEAKER_2: Is that clear?
SPEAKER_2: Because I, well, maybe, because they said the rebellion captures.
SPEAKER_3: Yeah.
SPEAKER_1: So you're saying the machines invented the time machine.
SPEAKER_3: Yes, because their goal was to go back, because John Connor was a pain in the butt.
SPEAKER_3: So they want to go back and kill.
SPEAKER_1: To remove him from the equation.
SPEAKER_3: Exactly.
SPEAKER_3: So in order to save, you know, him, then they send Reese back to him.
SPEAKER_2: You're right.
SPEAKER_2: Because Reese even says the machines were smashed.
SPEAKER_2: We had won.
SPEAKER_2: There's that line that Kyle Reese says.
SPEAKER_3: Did I just out-key?
SPEAKER_3: Oh.
SPEAKER_3: But you would not hear that sound in space.
SPEAKER_2: I feel, I feel terrible.
SPEAKER_2: Now you're going to invent time travel to go back in time and kill you before you say that.
SPEAKER_2: And then I can just say, oh, yes, the machine's invented time travel.
SPEAKER_2: Or didn't we have somebody else in the studio?
SPEAKER_2: What happened to her?
SPEAKER_1: So there's something else they got right in the movie.
SPEAKER_1: There's the scene where Sarah Connor's actual twin double is shown in the film.
SPEAKER_2: That's in the second movie.
SPEAKER_1: Oh, that's the second movie.
SPEAKER_1: Yeah, so she's there at the playground watching the children play.
SPEAKER_1: And a nuclear device goes off over, I guess that's Los Angeles, in the background.
SPEAKER_1: And so, in a nuclear device, the energy that reaches you first is the light from the explosion.
SPEAKER_1: Then the shockwave reaches you, okay?
SPEAKER_1: So you get the light, and it is hugely intense, and it basically vaporizes you.
SPEAKER_1: Or it'll melt you, it'll vaporize you, it'll burn you.
SPEAKER_1: Then the shockwave, which is moving at the speed of sound, rather than the speed of light, follows the light, and that's what comes later, and then breaks everything apart.
SPEAKER_1: Then you get the air, the expanding air, which then blows everything into the winds.
SPEAKER_1: All we are is dust and the wind.
SPEAKER_2: Wind.
SPEAKER_1: So they got that right, the three forces that operate in the aftermath of a nuclear explosion.
SPEAKER_3: So that made you happy.
SPEAKER_3: You weren't confronting anybody at a dinner party later.
SPEAKER_1: In the face of having to show something that disastrous, yes, they got their physics right.
SPEAKER_2: That damn scene gave me nightmares for like a month.
SPEAKER_1: Yeah, it's pretty creepy.
SPEAKER_2: And Neil's giggling here.
SPEAKER_2: Still, the nuclear explosion was accurate.
SPEAKER_1: So is there any physics you can tell me about the time travel?
SPEAKER_2: Well, they never really talk about it.
SPEAKER_2: I mean, the expanding sphere and all that, that was pretty cool, but they never really talk about it.
SPEAKER_2: The idea that only living tissue can go through in time, but that's just a...
SPEAKER_1: That bugged me though, because you're...
SPEAKER_2: That's a plot device.
SPEAKER_1: Wait, wait, wait.
SPEAKER_1: I even tweeted this.
SPEAKER_1: Your hair is dead, so he would have come back bald.
SPEAKER_2: Right, yeah.
SPEAKER_2: I remember thinking that as well, and like your fingernails, and basically your outer layer of skin.
SPEAKER_1: Yeah, yeah.
SPEAKER_3: He'd look like he'd been Lutford.
SPEAKER_1: He'd look like he'd been Lutford.
SPEAKER_1: He would be all dermis instead of epidermis.
SPEAKER_2: But Reese actually says something about...
SPEAKER_2: There's something about the energy field generated by a living body.
SPEAKER_2: So maybe that encompasses your hair.
SPEAKER_2: Now, I don't have to worry about that, being relatively hairless myself.
SPEAKER_2: Okay.
SPEAKER_2: But the movie...
SPEAKER_2: The beauty of it is that the plot all holds together.
SPEAKER_2: It's not just somebody traveling back in time and then doing stuff.
SPEAKER_2: The movie...
SPEAKER_2: The time travel is part of the movie.
SPEAKER_2: Reese has to go back in time to impregnate Sarah Connor so that she can give birth to John Connor.
SPEAKER_2: And he has...
SPEAKER_2: I love it when he has the picture of her.
SPEAKER_1: Yes, I love that.
SPEAKER_2: And he's looking at that picture, and he says, I always wondered what she was thinking at that moment when this picture was taken.
SPEAKER_2: And at the end of the movie...
SPEAKER_1: That's the moment.
SPEAKER_2: She's thinking of him.
SPEAKER_2: I mean, in a movie, with Arnold Schwarzenegger and all this, and I'm like getting choked up.
SPEAKER_1: Come on.
SPEAKER_1: Actually, that's not what I thought she was thinking.
SPEAKER_1: I thought she was just terrified of what was in her future.
SPEAKER_1: I wasn't getting all...
SPEAKER_2: Well, she's looking to the future.
SPEAKER_1: All interpersonal about it.
SPEAKER_2: About how she was...
SPEAKER_2: But she was saying, you know, you'll never know your father or something.
SPEAKER_2: She was actually thinking about Kyle.
SPEAKER_1: So just to get the genetics of this straight, he is his own father?
SPEAKER_2: He's John Connor's father.
SPEAKER_1: So he's John Connor's son, but he beget John Connor.
SPEAKER_2: No, no, no.
SPEAKER_2: John Connor is Kyle Reese's son, but he goes back in time, gets Sarah Connor pregnant, she gives birth to John Connor, and then John Connor has to send his father back in time.
SPEAKER_1: So that he could exist.
SPEAKER_2: Yes.
SPEAKER_2: And that's why the movie is so tight.
SPEAKER_2: And in fact, it's probably the only movie in the history of movies where the sex scene is, in fact, integral to the plot.
SPEAKER_2: You know, they had to say...
SPEAKER_2: Take that, censors.
SPEAKER_2: Sorry, Ms.
SPEAKER_2: Hamilton, you got to do it.
SPEAKER_1: You got to get laid, wherever that...
SPEAKER_1: Make it happen.
SPEAKER_2: Yeah.
SPEAKER_1: Okay, very cool.
SPEAKER_2: And that line has never worked for me, though.
SPEAKER_2: Come with me if you want to live.
SPEAKER_2: You know, it doesn't actually work at the bar, sadly.
SPEAKER_3: Now, oh, was that one of the lines that you guys missed?
SPEAKER_2: No, actually, Reese says that.
SPEAKER_2: The Terminator says that in the second movie, which is an homage to the first movie.
SPEAKER_2: Yes.
SPEAKER_1: You got it, you got it.
SPEAKER_1: So, any time travel movies I've left out?
SPEAKER_1: I mean, those are good.
SPEAKER_1: Well, back to the future.
SPEAKER_1: That's worth its own segment.
SPEAKER_1: I want to save that for the last segment of StarTalk.
SPEAKER_1: Yeah, yeah, yeah.
SPEAKER_1: So, with all this time travel, so what we're confessing here, or recognizing here, is that they don't put much physics in the time travel.
SPEAKER_1: They just assert that it can exist and then tell their stories behind it, right?
SPEAKER_2: I think that's pretty close.
SPEAKER_1: How about Somewhere in Time?
SPEAKER_1: Do you remember that?
SPEAKER_1: Once again, Chris Reed.
SPEAKER_2: I haven't actually seen it.
SPEAKER_3: Oh, is that the one where he falls asleep holding the penny and he's thinking really hard?
SPEAKER_1: So that's time travel, a chick flick time travel.
SPEAKER_1: That's what that was.
SPEAKER_2: Which is probably why I've never seen it.
SPEAKER_1: It was romantic.
SPEAKER_1: It was.
SPEAKER_3: It was.
SPEAKER_2: My wife wants me to see that movie.
SPEAKER_2: It's like, I...
SPEAKER_3: Dude, that's a major point.
SPEAKER_2: Aliens?
SPEAKER_2: No.
SPEAKER_2: Rockets?
SPEAKER_2: No.
SPEAKER_1: Yeah, there's no explosions.
SPEAKER_1: There's no aliens.
SPEAKER_1: There's no tidal waves.
SPEAKER_1: But it's love.
SPEAKER_3: It's the strongest force in the universe.
SPEAKER_1: Love being that which brings you back through time.
SPEAKER_1: What I liked about it was, because I've thought about this often, if I go back through time, I need currency of the period.
SPEAKER_1: I cannot bring a Roosevelt dime back to a pre-Roosevelt era and spend that money and have anyone think it's real money.
SPEAKER_2: That's right.
SPEAKER_1: You need cash serving the time that you're in.
SPEAKER_1: And they did this in Star Trek because they had a wardrobe.
SPEAKER_1: They'd say, here, wear this and wear that.
SPEAKER_1: And of course, my favorite line back in the Star Trek IV was when Spock gets on the bus.
SPEAKER_2: Yeah, yeah.
SPEAKER_1: And then he gets off the bus, and he's, what is exact change?
SPEAKER_1: And I said, Spock, aren't you smart enough to at least done your homework and figure this out?
SPEAKER_2: No, that's not the problem.
SPEAKER_2: He did too much LDS at Berkeley.
SPEAKER_1: Is that what that is?
SPEAKER_2: Well, that's what Kirk says.
SPEAKER_1: We've got to take a quick break, but more StarTalk when we return.
SPEAKER_1: This is StarTalk Radio, welcome back.
SPEAKER_1: The most recent time travel movie I can think of is Hot Tub Time Machine.
SPEAKER_2: Yeah.
SPEAKER_1: Did you see that film?
SPEAKER_2: Yes, I did.
SPEAKER_1: I did not.
SPEAKER_1: Tell me about the science in that film.
SPEAKER_2: It's actually one of the most scientifically accurate movies I have ever seen.
SPEAKER_2: Yes, this endorsement paid in full by whatever studio made that movie.
SPEAKER_1: Surely something in the interaction of the alcohol and the circuit board could have turned the tub into a time machine.
SPEAKER_3: That's what I'm thinking, the right alcohol content, the electricity, the marriage of the two, it's fantastic.
SPEAKER_2: Whenever I'm in a hot tub and I spill a lot of alcohol on the control panel, I flash back to the 80s.
SPEAKER_2: So I think actually a factual basis in this way.
SPEAKER_1: Well, it can't be any more or less believable than a flux capacitor.
SPEAKER_1: Come on now.
SPEAKER_3: That's a better name.
SPEAKER_2: I have a flux capacitor, don't you?
SPEAKER_1: I'm not authorized to.
SPEAKER_2: Oh, I see, I see.
SPEAKER_2: You have an entire planetarium, but not a flux capacitor.
SPEAKER_2: Oh, I see.
SPEAKER_1: So let's talk stuff about Back to the Future.
SPEAKER_1: First, it's one of the great time travel movies of all time, I think.
SPEAKER_1: And is there any moments for each of you that rise above the rest in the time travel aspects of the film?
SPEAKER_2: Wow, that rise above...
SPEAKER_2: Well, yeah, sure.
SPEAKER_2: At the end of the movie, when he goes back to the future, there are subtle changes that happen.
SPEAKER_2: And I didn't even notice it the first time, in fact.
SPEAKER_2: It wasn't until I went to see the movie again.
SPEAKER_1: Because he actually changed the future by having been in the past.
SPEAKER_2: Right, he...
SPEAKER_1: Yeah.
SPEAKER_1: So he changed his present.
SPEAKER_2: Yeah, by replacing his father in the tree, there's a series of events that cascades into the future.
SPEAKER_2: And so when he goes back to the future, things are different.
SPEAKER_2: And they threw in...
SPEAKER_1: So give me a list of some of those things that are different.
SPEAKER_2: Well, as he's leaving the barn, after he goes back into the past in 1955, he runs over one of the pines.
SPEAKER_1: Because he restarts the DeLorean.
SPEAKER_2: Yes.
SPEAKER_1: No, no, no, as he comes back through time, the DeLorean accidentally drives over one of the...
SPEAKER_2: No, no, no.
SPEAKER_2: Oh, he's coming back out.
SPEAKER_2: He comes back in time.
SPEAKER_2: He's in the barn.
SPEAKER_2: The farmer comes out and is gonna...
SPEAKER_2: Shoot him.
SPEAKER_1: And farmers always do.
SPEAKER_1: Yes, yes.
SPEAKER_1: At night, when you go into their barn.
SPEAKER_2: Exactly.
SPEAKER_2: And so Marty gets in, he starts the DeLorean up, crashes through the door, and runs over one of the pines.
SPEAKER_2: And you hear old man, whatever his name is, say, my pine!
SPEAKER_1: And the estate sign that talked about the future real estate that would go there, described it as Twin Pines.
SPEAKER_2: Twin Pines Mall is the name of the mall where he and Doc Brown are testing out the DeLorean.
SPEAKER_1: So we're to believe, surely accurately, that this mall was once this farmland.
SPEAKER_2: Yes.
SPEAKER_2: And so when he goes back to the future.
SPEAKER_2: Yeah, of course.
SPEAKER_2: Yeah, well, you know, and he goes back to the future and you see the sign for the mall says, I think it was Lone Pine Mall.
SPEAKER_1: Lone Pine Mall.
SPEAKER_2: Yeah.
SPEAKER_1: Instead of Twin Pine Mall.
SPEAKER_2: And I don't remember any.
SPEAKER_1: And they don't make a big deal of it.
SPEAKER_1: The camera just pans riot.
SPEAKER_2: That's my favorite thing in a movie is where they just sort of toss something in there and let you figure it out for yourself.
SPEAKER_1: That means you have to pay four times to see the movie.
SPEAKER_2: I didn't notice that until the second time I saw the movie.
SPEAKER_2: I was floored by this when I saw it.
SPEAKER_1: I caught it like the fifth time.
SPEAKER_1: So it was a little slower than you.
SPEAKER_2: But it really subtle.
SPEAKER_3: Yeah, yeah, I caught it.
SPEAKER_2: There is a continuity error that I caught right away.
SPEAKER_3: Ooh.
SPEAKER_2: Really?
SPEAKER_2: Well, Marty writes a note to Doc Brown and leaves it for him.
SPEAKER_2: And when Marty goes back to the future, and again, spoiler alert here, and Doc Brown opens up his jacket and there's a bulletproof vest.
SPEAKER_2: And Marty says, how did you know?
SPEAKER_2: Doc Brown holds up the note.
SPEAKER_2: He taped it back together after tearing it apart.
SPEAKER_2: And the handwriting is different on the note.
SPEAKER_2: And I only remember that because Marty signed it and it went like across a crease or something.
SPEAKER_2: And his signature was in a different place.
SPEAKER_2: And I remember sitting in the theater thinking, wow, the note's different.
SPEAKER_2: And my second thought was, wow, I'm a giant dork.
SPEAKER_2: Wow.
SPEAKER_1: And were you alone in the theater when you saw it?
SPEAKER_3: No, script supervisors get fired for that sort of thing.
SPEAKER_1: Uh-oh, you just call someone the job.
SPEAKER_2: Oh man, well, it was filmed what, 25 years ago.
SPEAKER_3: Yeah, probably retired now.
SPEAKER_1: So your point is this.
SPEAKER_2: Ah, that kid on the radio was.
SPEAKER_1: You pay close enough attention to the original signature and notice that it went across a crease in the paper.
SPEAKER_2: Or something like that.
SPEAKER_2: You'll see that the note is different.
SPEAKER_1: A continuity.
SPEAKER_1: All right, anything else you notice?
SPEAKER_2: Fairly trivial error.
SPEAKER_1: Yeah, that is as geek.
SPEAKER_1: I don't know if I can match that.
SPEAKER_1: I'll try hard, but go on.
SPEAKER_1: Give me another one.
SPEAKER_2: I don't know.
SPEAKER_2: No, no, just some more.
SPEAKER_2: Do you have something in mind?
SPEAKER_1: Well, so, go any other.
SPEAKER_2: There's no such thing as a flux capacitor.
SPEAKER_1: Really?
SPEAKER_3: That we know of.
SPEAKER_1: That we know of.
SPEAKER_1: I'm not authorized to dive.
SPEAKER_1: So.
SPEAKER_2: The idea of a DeLorean being unreliable seems fairly accurate.
SPEAKER_1: Now, how about this?
SPEAKER_1: The lawyers are calling.
SPEAKER_1: Have you heard anyone ever pronounce Giga as Jigga?
SPEAKER_2: Oh, yes, of course.
SPEAKER_2: Yeah.
SPEAKER_1: You have?
SPEAKER_2: No, no, no.
SPEAKER_3: Outside of rap songs?
SPEAKER_1: Oh, Jig.
SPEAKER_2: Yeah, get Giga with it, I think is the...
SPEAKER_2: Yeah.
SPEAKER_2: No, and in fact, that really bugged me in the movie.
SPEAKER_1: Yeah, he said...
SPEAKER_2: Jigga Watt.
SPEAKER_1: Jigga Watt, yeah.
SPEAKER_1: Yeah, that's unfortunate.
SPEAKER_1: So how about, here's something you might not have known.
SPEAKER_1: Do you remember when Doc Brown is doing his wire tweaking in anticipation of the lightning bolt near the clock, and the cop comes up, okay?
SPEAKER_1: And he says, do you have a permit for that?
SPEAKER_2: Yes.
SPEAKER_1: Okay, and then we just continue.
SPEAKER_2: Well, he pulls his wallet out and says, yeah, let me see if I have one here, and he's pulling out money.
SPEAKER_1: He's pulling out money.
SPEAKER_2: Oh, I never noticed this.
SPEAKER_1: No, no, you reason why you didn't notice because that scene was cut.
SPEAKER_1: It's in the DVD extras.
SPEAKER_2: I've never seen that in the theater.
SPEAKER_1: No, it was not in the theaters.
SPEAKER_2: No.
SPEAKER_2: Then I saw it on TV.
SPEAKER_2: I've not seen it on TV.
SPEAKER_3: Well, then you have a widescreen TV in your house is what you're saying.
SPEAKER_2: I, in fact, do.
SPEAKER_2: But I never saw it on DVD, and I know I've seen that scene.
SPEAKER_1: They cut that scene.
SPEAKER_1: It was originally cut from the movie, and I was kind of glad it was cut because he's not a bribing kind of guy.
SPEAKER_1: It was actually out of character with him.
SPEAKER_2: But he was very rich.
SPEAKER_2: I thought you were about to say he pulls money out, and it's modern money.
SPEAKER_1: Oh, no, I didn't look.
SPEAKER_1: I was just shocked that he's bribing the cop, and that's how we can continue with this experiment.
SPEAKER_2: Well, I know I've seen that scene.
SPEAKER_2: I just don't know where.
SPEAKER_2: I mean, I've seen this movie for a gazillion times.
SPEAKER_2: He saw it at the Planetarium.
SPEAKER_2: Four gigawatt times.
SPEAKER_2: And yeah, so I know I've seen it, but not on DVD.
SPEAKER_2: So maybe some version on television, they showed the DVD version.
SPEAKER_1: And of course, my favorite is Mr.
SPEAKER_1: Fusion at the end there.
SPEAKER_2: That's awesome.
SPEAKER_1: That's so good.
SPEAKER_1: Mr.
SPEAKER_1: Fusion, that's how in the future, rather than finding plutonium, which by the way is an element named after Pluto, believed at the time it was named to have been a planet, discovered in 1940, 10 years after Pluto itself.
SPEAKER_2: I thought it was named after Plutarch.
SPEAKER_1: So not.
SPEAKER_1: And they saved the element after uranium for the name plutonium.
SPEAKER_1: So after neptunium.
SPEAKER_1: So you have uranium, neptunium, plutonium, three consecutive elements on the periodic table.
SPEAKER_1: Pluto got on the periodic table on false pretense.
SPEAKER_2: You're just waiting for Tysonian, aren't you?
SPEAKER_1: So we got to wrap this up.
SPEAKER_1: This has been StarTalk Radio.
SPEAKER_1: I want to thank my guests and as always, I want to bid you to keep looking up.