JAD ABUMRAD: This is Radiolab. I'm Jad Abumrad.

ROBERT KRULWICH: And I'm Robert Krulwich.

JAD: And this hour we're talking about space, sending stuff into space, little messages in bottles or capsules as it were, so that the extraterrestrials of the future might one day find it.

ROBERT: If there are any.

JAD: Well, yes. Yes. But surely there are. I mean, someday Anne Druyan's space capsule is bound to run into someone and they'll know about us.

ROBERT: Well I—just a second here. I know that the Anne story was beautiful and that you're in some kind of romantic haze ...

JAD: But hey!

ROBERT: But if you would just get a little more cold-hearted here about solid facts, you might feel differently about this whole thing.

JAD: What do you mean?

ROBERT: Well, what do you think is the likelihood of Anne's message of love ever being read by an intelligent alien somewhere in the universe?

JAD: I see where you're going with this. Why do you have to ask that question? I mean, it's just a gesture. It's like a romantic thing.

ROBERT: No, no. This is an attempt, I think, to be fair to her, to have a real conversation. She wants someone to hear about this, but the chances are so remote when you consider the vastness of space. Suppose for example, you wanted to visit just—I don't know, make it easy, the very next star to us, okay? Actually, that's too lucky. To meet a civilization, I think it would be so odd to come out and find one in the very first stop. Let's go four stars out to a star called Zeta Tucanae.

JAD: I see. You've been digging up on this.

ROBERT: I look—I admit I looked it up. If we increase the speed of the Voyager capsule, Anne Druyan's message, from 35,000 miles an hour, that's how fast she was going, right?

JAD: Yeah, that's right.

ROBERT: Increase that speed to, say, a million miles an hour, how long do you think would it take for you to get to Zeta Tucanae?

JAD: 300 years.

ROBERT: Mm. 30,000 years.

JAD: Seriously? Whoa!

ROBERT: This, Jad Abumrad, is a 1,200-generation trip. Do you know where the Abumrads were 1,200 generations ago?

JAD: Where?

ROBERT: They were living in a cave beating on a drum. That's what they were doing. So imagine a space trip in which you have to go forward 1,200 generations. That's a long trip.

JAD: You're such a downer.

ROBERT: [laughs] Well, you think that's tough? Listen to this. There's a whole 'nother problem we're gonna have to deal with.

JAD: Oh boy.

ROBERT: Not the problem of distance. In this case, there's a problem of time. We have one of those too. Every civilization has an arc. You can think of it in threes.

ANNOUNCER: Step one.

[monkey sounds]

ANNOUNCER: Step two.

[ARCHIVE CLIP, radio: Let's welcome Seth Jackson and his Chesterfield Band of Florida.]

ANNOUNCER: And step three.

[Explosion. Man screaming.]

JAD: [laughs] What the hell was that?

ROBERT: Well, a million years ago we were practically apes.

[monkey sounds]

ROBERT: We'd hardly begun to have conversation. Now we have technology. We have radio and TV, and the universe can hear us.

[ARCHIVE CLIP, radio: How do you do?]

ROBERT: But how long will it be, do you think, before either from global warming or from some kind of war we're ...

[Explosion. Man screaming.]

JAD: The way the news has been recently? Days? Weeks?

ROBERT: [laughs]

JAD: In any case.

ROBERT: I'm gonna guess, like, a hundred million years or ten million years, but that's still a flash of time in a universe. Now suppose instead of one civilization, let's have two civilizations, another one out there.

JAD: Mm-hmm.

ROBERT: If they arrive on Earth ready to talk and we're, oh ...

[monkey sounds]

ROBERT: ... then there's no way to have a conversation. Or on the other hand, if they arrive on Earth after ...

[Explosion. Man screaming.]

ROBERT: ... then there's nobody to talk to.

JAD: I see.

ROBERT: And in a 14-billion-year universe with each civilization lasting, you know, only 10 million years, what are the chances of two civilizations lining up in perfect synchrony so they can have a conversation? It's almost mathematically impossible.

JAD: Yeah, fine, fine. But you have to keep something in mind though, right?

ROBERT: What?

JAD: As a rule, people who make the argument you're making right now, pessimists as it were, as a rule those people are usually proven wrong, It's—that's always how it goes. Let me play you something.

TIM FERRIS: Well, in the history of human navigation, lots of things have seemed too lonely and too far away until someone did them.

JAD: This is the guy who produced the Voyager record. His name is Tim Ferris.

TIM FERRIS: I mean, settling Polynesia in canoes, navigating by the stars and the currents alone, and hitting a tiny island after crossing hundreds or even thousands of miles of open ocean, that's a pretty lonely, scary thing to do and yet thousands of Polynesians did it. So I don't know what our future in interstellar space flight will be, but it's—it is important to keep in mind that the record of people who said that this or that journey of exploration is impossible or ill-advised, historically those sorts of predictions have not fared very well.

JAD: Yes, so you just hold your horses, right?

ROBERT: Well I mean look, Tim is talking about the Pacific Ocean, which is big, but I'm talking about the [bleep] universe here. Mine is a much, much bigger space and therefore a much, much, much bigger problem. And when I want to ask questions about space ...

ROBERT: Yes.

ROBERT: ... I usually go to this guy.

BRIAN GREENE: See, now I realize what's happening here. I hear you through that speaker, but not through my headphones.

JAD: Who is this?

ROBERT: This is Brian Greene, professor of mathematics and of physics at Columbia University.

ROBERT: Are we—are we on? Okay.

ROBERT: So Jad, I said to Brian if we've got a spacecraft crawling through this vast, vast empty universe, how long a trip is it for just to start from wherever it is now to the—to the end of the universe? And by the way, what is—where is the end of the universe?

BRIAN GREENE: That's a very natural question. You know, in most environments you can walk for a while, but then you hit the end, you hit the end of the city, the end of the state, the end of the country. But when it comes to the universe, we believe that there's probably no edge. There is no end. Now how do you picture that? Well, one possibility is that maybe that the universe just goes on forever.

ROBERT: Mm-hmm.

BRIAN GREENE: Space may just carry on, you can just keep on going and you'll just never run out of space. The other possibility is it could be that you walk off into space for a while and you keep on walking, and after a while you realize that you've actually circled back to your starting point. Sort of like on the surface of the Earth, you don't find an edge. You can't fall off the Earth's surface because when you walk ultimately you'll come back to your starting point. That idea may apply to the fabric of space, to the entire cosmos.

ROBERT: Although the Earth analogy is a little insufficient because when I'm walking in Central Park, I am on the edge of the Earth, because when I look down I see Earth, but when I look up I see non-Earth, I see gas around the Earth. So I'm at the edge.

BRIAN GREENE: Well ...

ROBERT: It's as if I were on a balloon. I'm on the surface of the balloon looking out at non-balloonness.

BRIAN GREENE: Yeah, that's where the analogy fails. If you're on the surface of the Earth, you can jump off, you can jump up.

ROBERT: Yeah.

BRIAN GREENE: So it feels like you're on an edge. But in the universe there is no notion of jumping off because there is nothing beyond the space that we inhabit. It is all there is, and there is nothing outside of it.

ROBERT: And now to make things even harder for our little capsule traveling through space, we now know that space, that the universe and the space that it is is expanding, constantly expanding. So imagine our little craft, all alone in nothingness, and every minute there's more nothingness and more nothingness and more nothingness and more ...

ROBERT: Has this always been happening?

BRIAN GREENE: We think it's been happening since the very beginning. So if the Big Bang was the origin of the universe then this expansion has been going on for 13.7 billion years.

ROBERT: So there's more space all the time?

BRIAN GREENE: Yes.

ROBERT: Does that mean that it takes a longer time to go from one part of the universe to another, is that ...

BRIAN GREENE: Absolutely. Absolutely.

ROBERT: So when you say something like the universe is expanding, what that seems to mean to you is that the empty spaces in the universe are getting bigger?

BRIAN GREENE: Yes. So the—the intuitive but wrong picture would be that you picture the universe expanding into a pre-existing space, a pre-existing realm that the universe is now filling.

ROBERT: Like a balloon.

BRIAN GREENE: Like a balloon. Filling, say, the room in which you're blowing it up.

ROBERT: Yeah.

BRIAN GREENE: But that imagery is wrong in the following way: It's not that the universe is expanding into a pre-existing space, it's that as the universe expands it creates more space. It creates the new space that it then inhabits.

ROBERT: Does that mean that there's no middle of the universe?

BRIAN GREENE: Yes. The old idea was that there is a central point in the universe, and the old idea was that we were at that central point in the universe. But in the current way and more modern way of thinking about the universe, there is no center. The universe is actually expanding, but it's not expanding from a certain point in space. All of space is stretching uniformly.

ROBERT: Brian Greene is professor of physics and mathematics at Columbia University. This leaves us in a sort of strange position.

JAD: Yeah, lonely position.

ROBERT: In the sense that we have this little capsule riding somewhere in a space which just keeps changing. We don't know where it is or where we are relative to other things, and whatever we know is changing all the time. It used to be so different. Neil deGrasse Tyson who runs the Hayden Planetarium in New York City says once upon a time we knew where we were, at least we thought we knew where we were, and we were the stars.

NEIL DEGRASSE TYSON: Well, before Copernicus, the idea of our place in the universe was largely accepted to be the center. It looked that way, for sure. You stand here on Earth and look up and the sun rises and sets and the moon rises and sets and the stars rise and set and the planets rise and set. When Copernicus came around, he put the sun in the middle of the known universe, allowing the planets to then go around the sun, relegating Earth to the status of a planet being one of these objects that goes around the Sun.

ROBERT: And that was a very dangerous idea at the time, apparently.

NEIL DEGRASSE TYSON: Yes, because that idea conflicted with all prevailing interpretation of scripture. It had deep societal ramifications, and Copernicus knew this. He knew it so well that he said, "I'm gonna make sure I'm dead before this hits the bestseller list." So ...

ROBERT: You mean, he didn't want to publish during his own lifetime?

NEIL DEGRASSE TYSON: This book was basically published on his deathbed.

ROBERT: Copernicus was 1600s?

NEIL DEGRASSE TYSON: Oh, 15.

ROBERT: 15? Okay.

NEIL DEGRASSE TYSON: Oh, yeah. 1543 I think was the pub date.

ROBERT: So now what happens? So—so now we're no longer—humankind is no longer at the center of things. Now what?

NEIL DEGRASSE TYSON: Well, we're no longer at the center of the then-known universe.

ROBERT: Right.

NEIL DEGRASSE TYSON: The then-known universe was the objects of the solar system, the planets. But you look up at the night sky beyond the planets, what do you see? Stars. There's stars in every direction. In fact, if you count how many stars are to your left, how many are to your right, how many are above and below—it's about the same in every direction you look. Hey, maybe even if Earth is not the center of the solar system, the solar system is in the center of the rest of the universe.

ROBERT: Yeah.

NEIL DEGRASSE TYSON: Yeah. That's the ticket, okay? Now we can dig out of this hole that Copernicus put us in.

ROBERT: Yeah.

NEIL DEGRASSE TYSON: Let's go ahead and do that.

ROBERT: So our group is king.

NEIL DEGRASSE TYSON: Oh yeah. Our little family of planets, we're in the center. And so that prevailed for a while, because it's a comforting concept not only for the public but for the scientists as well. It wasn't until the 1920s where Harlow Shapley, then head of Harvard College Observatory, noticed globular clusters. Those were more in one direction of the sky than the other.

ROBERT: Huh.

NEIL DEGRASSE TYSON: And he deduced that these things ought to know where the center of the gravity is, rather than these measly handful of stars that are sitting in front of us around on the sky.

ROBERT: Oh, you mean these big, fat concentrations of stars?

NEIL DEGRASSE TYSON: Big, fat, hundred thousand star beehive concentrations of stars. Star clusters. They ought to know where the center of the galaxy is, even if these single stars don't. And so he deduced that the center of the galaxy was off in the direction of Sagittarius on the sky, okay? So now people are fighting that, people are fighting that, but then all hell breaks loose because 1920s come in, Edwin Hubble grabs the business end of the biggest telescope of the day, and determines that these fuzzy things among the stars are not the same distance as the stars themselves. They're vastly farther away. In fact, you know, they kind of look like what this collection of stars might look like from afar. In fact, maybe they are other Milky Ways, maybe they are other galaxies, maybe we're not the whole story.

ROBERT: Oh boy.

NEIL DEGRASSE TYSON: Man!

ROBERT: Meanwhile, the sky keeps getting bigger and bigger and deeper and deeper and bigger and deeper and bigger and deeper. Yeah.

NEIL DEGRASSE TYSON: Man, oh this was terrible for the ego.

ROBERT: I can tell you I'm disappointed myself.

NEIL DEGRASSE TYSON: Oh, man. And so now okay, maybe we're in the center of the—that universe.

ROBERT: Yeah, let's hope for that.

NEIL DEGRASSE TYSON: Because we look this way, we see about the same number of galaxies this way as that way as that way as that way. Kind of looks like we're at the center. And they're all receding from us. So hey, we're at the center then. You know, but now we're smarter than this now. We're saying we're not gonna fall for that, okay? We've fallen for that one nine times already. We're not gonna fall for this again.

ROBERT: You mean, somebody's sitting there in the corner thinking, "Every time we make ourselves the star of the show, we're wrong."

NEIL DEGRASSE TYSON: We're wrong. So I'm—we're not gonna make that mistake again. And so you then apply Einstein's general theory of relativity, and it says if you live in an expanding universe, in this fabric of space and time, no matter where you are it will look like you're at the center.

ROBERT: Which means what? There is no center?

NEIL DEGRASSE TYSON: Yes.

ROBERT: Every center is an illusion.

NEIL DEGRASSE TYSON: Yes. And so that's how we could look like we're at the center of the actual universe, even though we're not, because everybody sees the same signature of the expansion. Now there's an even stronger argument for—than the numerics. Let's look at the ingredients of the human body. You learn from biology class we're mostly water.

ROBERT: Right.

NEIL DEGRASSE TYSON: But what is water mostly?

ROBERT: Hydrogen and oxygen.

NEIL DEGRASSE TYSON: Hydrogen. Hydrogen and oxygen. Let's look in the cosmos. The number one ingredient in the cosmos is hydrogen. Next in the universe: oxygen. Next on Earth and in life: oxygen. Next in the universe: carbon. Next in life: carbon. Next in the universe: nitrogen. Next in life: nitrogen. One for one you go down the list. We are not simply in this universe, the universe is in us.

ROBERT: So we're not the center of the universe, we are on the side. Then our gang is not the center of everything but it's just out on a wing, and then a galaxy that we're a part of is one of many. And the fact that we are alive is maybe not unique.

NEIL DEGRASSE TYSON: I got something worse ...

ROBERT: How low can we go?

NEIL DEGRASSE TYSON: Oh, we can go lower. You ready?

ROBERT: Yeah.

NEIL DEGRASSE TYSON: You want to go lower?

ROBERT: Yeah.

NEIL DEGRASSE TYSON: Okay. We may not even be the principal stuff of the universe. That's how insignificant we are, okay?

ROBERT: What do you mean?

NEIL DEGRASSE TYSON: We have learned the universe has this stuff that has gravity but doesn't otherwise interact with matter as we know it. It doesn't shine. It doesn't reflect. It doesn't block. It's dark. It's called dark matter.

ROBERT: So how much of the universe is the stuff that we can either see or that is blocked but we can kind of detect?

NEIL DEGRASSE TYSON: Four percent.

ROBERT: [laughs]

NEIL DEGRASSE TYSON: [laughs]

ROBERT: What are you talking about?

NEIL DEGRASSE TYSON: I told you we're gonna sink low. You asked how low can we go?

ROBERT: You mean, like, 96 percent of the universe is missing?

NEIL DEGRASSE TYSON: 96 percent of the universe is not us, it's something else.

ROBERT: Is it your working bias that if I came to you with a new discovery in which we were less important, or a discovery which proposed that we were more important, that you would guess that my scientific discovery that said we are less important is more likely to be right?

NEIL DEGRASSE TYSON: No doubt about it. That's correct. Now you call that a bias, but I don't. I call that track record. [laughs]

ROBERT: [laughs]

NEIL DEGRASSE TYSON: Okay? Track record. We have among our exhibits here, our timeline of the universe that begins with the Big Bang and you walk the equivalent length of 100 yards, and time goes by with every step you take. 70 million years depending on how long your legs are. 70 million years per step.

ROBERT: Yes.

NEIL DEGRASSE TYSON: Per step. And you do that for a hundred yards. And you get near the bottom, it's a gently sloping ramp. You get to the bottom of the ramp, and then you're reminded that 65 million years ago the dinosaurs were roaming the Earth ready to become extinct. And then you take one more step on this ramp and you reach modern-day. Well, at the end of that ramp we have mounted a single strand of human hair. The left side of that hair, cavemen were drawing cave paintings. The right side of that hair is this conversation right now. So we are a speck on a speck on a speck on a speck.

ROBERT: And the speck that you just heard talking, who is over six feet tall by the way, is Neil deGrasse Tyson, astrophysicist and director of the Hayden Planetarium in New York City.

JAD: See that right there though, is why I think a lot of people don't like science. Because any time that anyone normal wants to say that we are important ...

ROBERT: Mm-hmm?

JAD: ... there's some scientist in a corner who's yelling, "Bah, that's just a speck!"

ROBERT: That's, you know, science's preference, but I don't—I think artists, Shakespeare for example, who says what a piece of work is man, how noble in reason and all. It seems like it's art's job to say that we are special, significant, glorious, and it's science's job to say, "No, we're not."

JAD: Right. Well—well, maybe art is where we should go next. Stay with us. I'm Jad Abumrad.

ROBERT: And I'm Robert Krulwich.

JAD: And Radiolab will continue in a moment.

 

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