Season 4 Time Capsule (Part 2): Cosmic Queries

Neil deGrasse Tyson, your own personal astrophysicist, answers your questions about dark matter, black holes, light, time, relativity and the fabric of our universe in your favorite Cosmic Queries episodes of Season 4.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now. Welcome to StarTalk Radio. I'm your host Neil deGrasse Tyson. I'm an astrophysicist and director of New York City's Hayden Planetarium, right here in New York City, part of the American Museum of Natural History. The show you're about to hear is another season four time capsule, this time featuring your favorite Cosmic Queries episodes. In Cosmic Queries, my comedian co-host and I grapple with a variety of questions asked

• 0:46Neil deGrasse Tyson?

  by you, our audience. Based on our poll, your favorite Cosmic Queries were all about dark matter and dark energy.

• 0:53Speaker 01

  Who discovered dark matter? And I know it wasn't Al Gore.

• 0:58Neil deGrasse Tyson?

  Ah.

• 0:59Speaker 01

  Sorry, Al.

• 1:00Neil deGrasse Tyson?

  Yeah, he discovered it on the internet.

• 1:02Speaker 01

  On the internet.

• 1:04Neil deGrasse Tyson?

  Yeah, so dark matter was discovered in the 1930s by a dude named Fritz Zwicky.

• 1:09Speaker 01

  Not Fritz.

• 1:10Neil deGrasse Tyson?

  That's totally Fritz.

• 1:11Speaker 01

  Aw, man. Look at that dude, party. When did he have time to discover dark matter? That dude was always at a party.

• 1:16Neil deGrasse Tyson?

  So, he was Swiss-born, American, I don't know if he was ever naturalized, but his whole professional career was in America, and he worked at Caltech in Pasadena, California, the California Institute of Technology. And he was measuring the movement of galaxies. Now, the example I just gave with the sun and our solar system orbiting the galaxy, he did that same measurement for galaxies orbiting one another in a cluster of galaxies. So, he's measuring how fast these galaxies are moving and says, "The speed they're moving tells me how much matter should be there to account for the gravity." And he does the calculations, and he's off by a factor of five or 10.

• 1:59Neil deGrasse Tyson?

  Right, and he's double checks and triple checks his calculations, they continually don't match. And he said, "There's missing matter somewhere." And it was the beginning of the missing mass problem, today known as dark matter.

• 2:11Speaker 01

  I love it.

• 2:12Neil deGrasse Tyson?

  And there you have it, Fritz Zwicky. I think it was 1936.

• 2:15Speaker 01

  So, he's just covering a math era, is what we're saying.

• 2:18Neil deGrasse Tyson?

  Exactly. It was called the missing mass problem.

• 2:21Speaker 01

  Okay.

• 2:22Neil deGrasse Tyson?

  And it's the longest unsolved problem in modern astrophysics.

• 2:25Speaker 01

  Oh, and not what women are thinking?

• 2:27Neil deGrasse Tyson?

  (laughing)

• 2:28Speaker 01

  Really?

• 2:29Neil deGrasse Tyson?

  (laughing)

• 2:29Speaker 01

  Okay.

• 2:30Neil deGrasse Tyson?

  No, that would be a longer problem. You know, a related, can I give a related comment? The study of the universe is the second oldest profession.

• 2:40Speaker 01

  Seriously?

• 2:43Speaker 01

  How, how much dark matter or dark energy is predicted to be in the universe?

• 2:49Neil deGrasse Tyson?

  Hmm, well, so the number that we put forth. Well, so let me back up. We measure the stuff. And so it turns out when we try to make galaxies, uh, well, I mean, on a computer.

• 3:03Speaker 01

  I was about to say, did you just let me in on some top level stuff that I am not cleared to hear?

• 3:08Neil deGrasse Tyson?

  We have, yeah, that's slipped out.

• 3:10Speaker 01

  There are men in dark suits coming in. Hello, gentlemen. What? I didn't hear anything. What?

• 3:15Neil deGrasse Tyson?

  Yeah, look at this light. So we are, so the, it turns out before we understood how deep the dark matter problem was, we had a hard time making galaxies on a computer. You put in matter, you spin it up, you see if it's self-gravity, because matter attracts itself. You watch the computer, provided all your formulae are accurately captured in the program. Newton's laws of motion, differential equations that track where things move. And you put it all in there, you load it up, and we found out we can't make galaxies. Not only that, we can't make the structure of matter in the early universe unless we put dark matter in the equations.

• 3:57Speaker 01

  So something was missing.

• 3:58Neil deGrasse Tyson?

  Something was missing. And so not only does the universe show us it has dark matter, we need it in our formulations of the universe in order to create a universe that looks like the one that exists. So we have good theoretical confidence as well as observational requirement that dark matter is out there.

• 4:19Speaker 01

  And we, we think that that missing thing is dark matter and not love.

• 4:24Speaker 01

  You need love to make a universe.

• 4:25Neil deGrasse Tyson?

  An absence of love. No, it's too much love. It's too much is more gravity than we can account for.

• 4:32Speaker 01

  I do have a question based on something that you said, that things enter a black hole, but they don't leave.

• 4:37Neil deGrasse Tyson?

  Yeah.

• 4:38Speaker 01

  So.

• 4:39Neil deGrasse Tyson?

  Not really. I mean, they they sort of leave, but not really.

• 4:42Speaker 01

  Okay, because I'm imagining that the black hole needs like a massive super colonic or something. That's because when she blows, it's gonna be awful. Stand back, everyone.

• 4:52Neil deGrasse Tyson?

  Yeah, yeah, colonic. I forgot that word. I'd never think I'd ever use that word in an astrophysics conversation.

• 4:58Speaker 01

  And that's why I'm here. This is what I bring.

• 5:01Neil deGrasse Tyson?

  That'd be a great new storefront, Black Hole Colonics, you know, that would they would win in the colonics contest, I'm sure.

• 5:08Speaker 01

  I would see that in an episode of Doctor Who. I feel it coming on.

• 5:12Neil deGrasse Tyson?

  So black holes eat things, and as far as we know, they stay right there down in their center. But over time, the black hole slowly evaporates these particles. And Hawking first figured this out, and it's named in his honor. It's called Hawking Radiation. And given enough time, these particles inside the black hole will evaporate from just at the border of the event horizon. That's the place beyond which you don't return. But I throw in all your atoms, they come out one by one over time, very slowly. So it's an evaporation process, and it comes from quantum physics. It's a quantum physics phenomenon, actually. And I can I don't have I'm okay, I can get it in the next 30 seconds because we're gonna have to go to break in a moment.

• 5:55Speaker 01

  Okay.

• 5:56Neil deGrasse Tyson?

  So I'll tell you Hawking Radiation in 30 seconds. Ready?

• 5:58Speaker 01

  Ready.

• 5:59Neil deGrasse Tyson?

  Okay, so you remember E equals mc squared?

• 6:01Speaker 01

  Of course.

• 6:01Neil deGrasse Tyson?

  E equal E energy is equivalent to matter. Okay?

• 6:06Speaker 01

  Mm hmm.

• 6:06Neil deGrasse Tyson?

  So on the outer outside edge of a black hole,

• 6:09Speaker 01

  Yeah.

• 6:09Neil deGrasse Tyson?

  the gravitational field is so strong, the gravitational energy is so intense,

• 6:13Speaker 01

  Mm hmm.

• 6:14Neil deGrasse Tyson?

  the gravitational energy becomes matter, right at the outer edge of the black hole, and that matter escapes. So the black hole evaporates because its gravitational energy is getting converted into matter. And you know something, those particles that escape?

• 6:30Neil deGrasse Tyson?

  Invented out of the vacuum of space itself? Have the same inventory of all the particles that went in in the first place. The black hole did not forget what it had eaten.

• 6:43Speaker 01

  How does dark matter influence time?

• 6:45Neil deGrasse Tyson?

  Ooh, dark matter, like anything else in the universe that contains energy. Einstein's special theory of relativity says that time slows down in the presence of high sources of gravity. And so if you have a region where there's a lot of dark matter, if you can find a place near that dark matter that is high gravity from that dark matter, your time will tick more slowly. Your metabolism will metabolize less quickly.

• 7:18Speaker 01

  What would happen if all the dark matter in the universe suddenly vanished?

• 7:22Neil deGrasse Tyson?

  Awesome question. If all the dark matter vanished, our galaxy would fly apart because all the speeds of the orbits that all the solar systems have is the right speed for the regular matter plus the dark matter's gravity to contain it. If you instantly take away the dark matter, we fly away and all the orbits go cockamamie and galaxy clusters fly apart and everything goes haywire.

• 7:46Speaker 02

  Wow, I'm actually starting to get this.

• 7:54Neil deGrasse Tyson?

  Welcome back to StarTalk Radio and our season four Cosmic Queries Time Capsule. Next up, Dark Mysteries of the Universe, where comedian Leigh Anne Lord and I answer your questions on everything from the tiny electron to the higher dimensions of the multiverse.

• 8:12Speaker 01

  I have a question from Joe Vera and he says, I recently found out about something called dark flow. Isn't that a DJ?

• 8:20Neil deGrasse Tyson?

  Dark flow.

• 8:21Speaker 01

  Okay, I'm sorry. Yeah, exactly.

• 8:23Neil deGrasse Tyson?

  A beatboxing DJ, dark flow. That's a great name.

• 8:27Speaker 01

  It is, isn't it? It's like a cartoon. All right, now from what I gather, it is the-

• 8:31Neil deGrasse Tyson?

  The other great name for it was like MC squared, that's it, you know, if you want to be MC.

• 8:35Speaker 01

  I'm gonna pretend I didn't hear that. All right, from what I gather, it is the unexplained coherent motion of galaxies toward one side of the universe. Can you please elaborate on this phenomenon and is it and its possible ramifications for our understanding of the universe?

• 8:49Neil deGrasse Tyson?

  Yeah, there's something called the Great Attractor. It got labeled that because when you-

• 8:53Speaker 01

  I know that guy.

• 8:55Neil deGrasse Tyson?

  When you measure the speed of galaxies as they move in the universe, there are multiple ways to do this. One of them is just how fast is the universe expanding? So that's the speed they have just from the expanding universe. But while that's happening, galaxies are moving among themselves. For example, we are about to, in seven billion years or so, about to collide

• 9:14Speaker 01

  We better hurry.

• 9:14Neil deGrasse Tyson?

  with the Andromeda Galaxy. It's our nearest big galaxy. So we're about to collide, but the greater activity of the universe is expansion while galaxies are still moving among themselves.

• 9:26Speaker 01

  Okay.

• 9:27Neil deGrasse Tyson?

  Right? So, when you map the speeds of all these galaxies, it was found that there's a whole swath of galaxies in the universe that have sort of an extra motion towards one direction.

• 9:37Speaker 01

  Hmm.

• 9:37Neil deGrasse Tyson?

  So you don't know if they're escaping something or being drawn towards something.

• 9:41Speaker 01

  Run, everybody!

• 9:43Neil deGrasse Tyson?

  So, it's an interesting sort of phenomenon that's not completely explained.

• 9:47Speaker 01

  So you just didn't explain it?

• 9:49Neil deGrasse Tyson?

  That's true.

• 9:51Speaker 01

  According to the theory of multiverse, what is space, and he says I'll call it space, between universes? What is the space between universes?

• 9:58Neil deGrasse Tyson?

  Yeah, it's a higher dimension. Next question.

• 10:02Speaker 01

  Oh! And not the fifth dimension, as in the singing group.

• 10:06Neil deGrasse Tyson?

  Actually, there's a fifth dimension in there somewhere, but if you take the three dimensionality of our universe, and then you embed it among other universes in another kind of space, that's a higher dimension. And in fact, I hosted a panel on nothing.

• 10:22Speaker 01

  You hosted a panel on Seinfeld?

• 10:24Neil deGrasse Tyson?

  On nothing at my host institution, the American Museum of Natural History, and we talked about what is between galaxies if the multiverse produces galaxies. And it's a kind of nothing, but it turns out it's not the best nothing that you can come up with.

• 10:39Speaker 01

  It's like the dark alleys of the universe?

• 10:41Neil deGrasse Tyson?

  No, because that still has dimensions.

• 10:42Speaker 01

  Oh.

• 10:43Neil deGrasse Tyson?

  Is it nothing if nothing's there, but it still has a dimensionality? See, we got really deep. I mean, heads were exploding left and right.

• 10:51Speaker 01

  Yeah.

• 10:52Neil deGrasse Tyson?

  In the aisle.

• 10:52Speaker 01

  Like now.

• 10:53Neil deGrasse Tyson?

  So, no, it's what we would call the space of a higher dimension, which is not even our space, because it would not have the matter, it would not have the energy, it would not have the, anything that we associated with our stuff, or even with where our stuff isn't. Because outside of our universe, there's not even the nothing of space.

• 11:15Speaker 01

  Wow, no?

• 11:17Neil deGrasse Tyson?

  Well, because if space is nothing, then where there is no space, there's not even that nothing.

• 11:24Speaker 01

  Okay, next question.

• 11:25Neil deGrasse Tyson?

  Okay.

• 11:26Speaker 01

  I'm sorry, I'm not allowed to call next question.

• 11:27Neil deGrasse Tyson?

  All right, no, go for it, go for it.

• 11:29Speaker 01

  Because I'm just, what?

• 11:30Neil deGrasse Tyson?

  Um, go for it.

• 11:31Speaker 01

  Ah, I need to go back to school. Uh, is there anything smaller than the infinitely small? And can you put it in a way that does not make me hate that I don't even get to be in pre-calc till next year?

• 11:43Neil deGrasse Tyson?

  Ooh, high school student.

• 11:45Speaker 01

  Yes.

• 11:46Neil deGrasse Tyson?

  Nice.

• 11:46Speaker 01

  Can you smell that? Young person.

• 11:49Neil deGrasse Tyson?

  Uh, yes, so, uh, by the way, see, if you really like math, see if you can skip pre-calc and just go straight to calc. Just, just, tell them Tyson told you.

• 11:59Speaker 01

  Tyson told me. I have a, I have a note from my personal astrophysicist. Can I please get in?

• 12:03Neil deGrasse Tyson?

  And just go, see if you can go straight to calc. But, all right, so is there anything smaller than infinitesimally small?

• 12:09Speaker 01

  Mm-hmm.

• 12:10Neil deGrasse Tyson?

  Uh, yes.

• 12:12Speaker 01

  All right, next question.

• 12:13Neil deGrasse Tyson?

  No.

• 12:14Speaker 01

  You are so evil.

• 12:15Neil deGrasse Tyson?

  Okay, no, no, so here it is. Uh, the electron is smaller than the smallest thing we have ever measured. And in fact, it is so small, we do not know how small it is. We cannot measure it. It is so small. In fact, it could be so small as to not occupy any volume at all. As far as our measurement devices are concerned, it has no dimensions at all. The electron. So, the electron comes closest to infinitesimally small of anything we have ever known, thought of, dreamt of, or measured.

• 12:59Speaker 01

  Uh, approximately, how many stars are born and die each day?

• 13:03Neil deGrasse Tyson?

  Ooh, I love that.

• 13:05Speaker 01

  Now, what's a day?

• 13:06Neil deGrasse Tyson?

  Ah.

• 13:06Speaker 01

  How are we defining a day?

• 13:07Neil deGrasse Tyson?

  I'm assuming Earth Day.

• 13:09Speaker 01

  Let's assume.

• 13:09Neil deGrasse Tyson?

  And not somebody else's day, Earth.

• 13:11Speaker 01

  Earth.

• 13:12Neil deGrasse Tyson?

  Right. But of course, other planets have days.

• 13:14Speaker 01

  Mm-hmm.

• 13:15Neil deGrasse Tyson?

  Yes, in fact, Venus's day is longer than its year. Just chill on that one for a bit. So.

• 13:24Neil deGrasse Tyson?

  Leanne's face just scrunched up in a like.

• 13:26Speaker 01

  Cause I'm chewing on it. I'm actually chewing on it. That's.

• 13:29Neil deGrasse Tyson?

  Yeah, on Venus, the day lasts longer than a year, but we'll get back to that if if we go there. So now where was I before I distracted myself?

• 13:36Speaker 01

  How many stars?

• 13:37Neil deGrasse Tyson?

  How many stars are born each day? So you can do what's called a back of the envelope calculation.

• 13:42Speaker 01

  Mm hmm.

• 13:43Neil deGrasse Tyson?

  Ready? All right.

• 13:43Speaker 01

  Yes.

• 13:44Neil deGrasse Tyson?

  Our galaxy has about, just say, a hundred billion stars.

• 13:47Speaker 01

  Mm hmm.

• 13:48Neil deGrasse Tyson?

  Okay, and the universe has been around for about 10 billion years. With back of the envelope means you change the number to make the math easy. But your answer will be.

• 13:57Speaker 01

  I back of the envelope my taxes all the time.

• 13:59Neil deGrasse Tyson?

  So but your answer will be approximately correct. And later on, you could put the exact number in if you want the exact answer.

• 14:05Speaker 01

  Fine tune.

• 14:05Neil deGrasse Tyson?

  So say we have about 100 billion stars and the universe and the galaxy has been around for 10 billion years. Okay, so we have 100 billion stars. We've been around for 10 billion years. That means the galaxy makes 10 stars a year.

• 14:20Speaker 01

  That's an average.

• 14:21Neil deGrasse Tyson?

  Yeah, on average. That's right. If it made 10 stars a year throughout his whole life, we'd have 100 billion stars over the 10 billion years. That's how that works. So it makes about 10 stars a year. So that's about one a month. And so we don't quite make a star a day on average, about one a month.

• 14:37Speaker 01

  Okay.

• 14:37Neil deGrasse Tyson?

  We could live with that. However.

• 14:39Speaker 01

  Uh oh.

• 14:40Neil deGrasse Tyson?

  That's not actually how stars are born. They're born episodically in stars, in stellar nurseries, where thousands of stars are born all at the same time.

• 14:48Speaker 01

  Oh.

• 14:49Neil deGrasse Tyson?

  So if you're a planet in orbit around one of those stars, you'll see stars lighting up daily as they are born.

• 14:55Speaker 01

  It must be pretty.

• 14:56Neil deGrasse Tyson?

  Well, not daily, but frequently.

• 14:59Speaker 01

  Like poof, there's Brad Pitt.

• 15:00Neil deGrasse Tyson?

  Yeah.

• 15:00Speaker 01

  Poof, there's Angelina Jolie. How does the Higgs feel different from earlier ideas of an ether?

• 15:07Neil deGrasse Tyson?

  Oh, did he spell ether right? A E?

• 15:10Speaker 01

  Yes.

• 15:10Neil deGrasse Tyson?

  Yeah.

• 15:11Speaker 01

  Yes, the A is silent.

• 15:12Neil deGrasse Tyson?

  A silent, so it's a dipthong.

• 15:14Speaker 01

  It's a dipthong.

• 15:15Neil deGrasse Tyson?

  Yeah, I think it's a dipthong.

• 15:16Speaker 01

  That's very kinky.

• 15:17Neil deGrasse Tyson?

  Yeah.

• 15:20Neil deGrasse Tyson?

  They should invent a new bathing suit, the Dipthong, you know? That would be cool. So let me see, we only have like 20 seconds left.

• 15:27Speaker 01

  Yeah, because you're fooling around.

• 15:28Neil deGrasse Tyson?

  Let me see, well, I have to give half the answer and you're going to get the full answer at the end of the break. But the ether was this proposed medium of the cosmos through which light traveled. Because people knew that light was a wave and sound is a wave and you, sound doesn't move through a vacuum, does it? You ever remember the bell jar experiment where you have a bell ringing? You put a jar over it, you evacuate all the air and the bell shuts off. The bell is ringing and you can't hear it.

• 15:56Speaker 01

  Right.

• 15:56Neil deGrasse Tyson?

  It doesn't go through a vacuum, so neither should light, was the hypothesis. Because the ether was a thing, nobody knew what it was.

• 16:03Speaker 01

  Right.

• 16:04Neil deGrasse Tyson?

  That was proposed to allow light to vibrate its way from a star to us through the vacuum of space.

• 16:09Speaker 01

  Okay.

• 16:10Neil deGrasse Tyson?

  Because sound needs something to vibrate, the ground, the air. Sound doesn't travel through space, such was the tagline to the movie Alien in space.

• 16:18Speaker 01

  No one can hear you scream.

• 16:20Neil deGrasse Tyson?

  Yes. However, light travels through it, so surely there must have been a medium out there through which light can move and vibrate. And it was proposed to be the ether, but it was never found, never measured. It was never found, so, and it went away.

• 16:33Speaker 01

  So is the ether dark matter?

• 16:34Neil deGrasse Tyson?

  No, we learned that this, that light does not require any medium at all to vibrate, it is self vibrating.

• 16:41Speaker 01

  Oh, man.

• 16:41Neil deGrasse Tyson?

  Don't go there, stop, no, no.

• 16:44Speaker 01

  Oh, it hurts. That actually physically hurts.

• 16:47Neil deGrasse Tyson?

  I'm just talking universe here.

• 16:49Speaker 01

  Drain myself.

• 16:50Neil deGrasse Tyson?

  I'm just universe.

• 16:51Speaker 01

  Is it warm in here?

• 16:55Speaker 01

  But how do you know math is the language of the universe?

• 16:58Neil deGrasse Tyson?

  How do we know? Because the universe tells us. Eugene Wrigner, a physicist back in the 20th century, commented on the unreasonable effectiveness of mathematics.

• 17:09Speaker 01

  The unreasonable effectiveness.

• 17:10Neil deGrasse Tyson?

  Because we invented it, yet it accounts for the operations and motions of the universe. Since math is purely logical, it means the universe at its finest is logical.

• 17:21Speaker 01

  The math is Vulcan, love it. Adam Young wants to know, have we considered the consequences of tapping into the dark side of the force?

• 17:31Speaker 01

  And is the dark side of the force really stronger or just more loose?

• 17:36Neil deGrasse Tyson?

  Oh, well, all the forces we know don't have dark sides.

• 17:40Speaker 01

  You haven't met my mother.

• 17:43Speaker 01

  I'm sorry.

• 17:44Neil deGrasse Tyson?

  So, yeah.

• 17:52Neil deGrasse Tyson?

  Welcome back to StarTalk Radio. I'm Neil deGrasse Tyson. This time capsule features your favorite cosmic queries from season four. Next up, an episode we call Answers at the Speed of Light.

• 18:06Speaker 01

  Now, I heard lately that lasers have been used to try to direct lightning strikes. The laser is shot into the thunderhead clouds and the plasma flows the laser back. Is there a way to harness this energy and make lightning farms?

• 18:19Neil deGrasse Tyson?

  Well, first of all, that's the first I've heard of this, and I think it's amazing. And I can even explain how it works, even though I only just learned of it.

• 18:28Speaker 01

  Because you're that bad.

• 18:29Neil deGrasse Tyson?

  No.

• 18:31Speaker 01

  Cue music.

• 18:34Neil deGrasse Tyson?

  I did a theme.

• 18:35Speaker 01

  You do. You're the shaft of science.

• 18:39Neil deGrasse Tyson?

  Okay, now, sorry, I distracted myself. Where were we?

• 18:42Speaker 01

  Yes, you did. Lightning farms, sir.

• 18:44Neil deGrasse Tyson?

  So here's what happens. Lightning comes about because there's a difference in charge between a cloud and the ground beneath it.

• 18:52Speaker 01

  Yes.

• 18:53Neil deGrasse Tyson?

  And charges don't like being separate from one another. The molecules reach an excited state because they've lost their electrons. They don't like staying that way.

• 19:02Speaker 01

  Okay.

• 19:02Neil deGrasse Tyson?

  And all the electrons are sitting on the ground, and those electrons want to get back to the cloud. And so the cloud comes over, the electrons gather, and they're ready to rise up and reach the cloud again. Thus is born a lightning strike, which tells you that lightning goes from the ground to the cloud, not the cloud to the ground.

• 19:21Speaker 01

  Really?

• 19:21Neil deGrasse Tyson?

  Now, so if you take a laser that's very high power and you ionize gas at the atmosphere in one place versus another, you can build charges around where the cloud is and force a lightning bolt to go where you say so. Now, that's good.

• 19:42Speaker 01

  Yeah.

• 19:42Neil deGrasse Tyson?

  Now, if the person wants to know if we can make a lightning farm out of that, I say, why not? But it sounds great.

• 19:48Speaker 01

  It does.

• 19:49Neil deGrasse Tyson?

  You just have to watch out that your lasers aren't so powerful to ionize the air in places so that you can force a lightning discharge that you're using more energy than you get back from the lightning itself.

• 19:59Speaker 01

  Because then that would be inefficient.

• 20:00Neil deGrasse Tyson?

  Then you're not farming anything.

• 20:03Speaker 01

  Right now.

• 20:03Neil deGrasse Tyson?

  You're getting less than what you started with. Now, it turns out the act of forming a raindrop in a cloud... Takes some charge out of the cloud and brings it to the ground.

• 20:13Speaker 01

  Okay.

• 20:13Neil deGrasse Tyson?

  So you're relying on the sun, which evaporated the water in the first place to make the cloud.

• 20:18Speaker 01

  Mm-hmm.

• 20:19Neil deGrasse Tyson?

  To then drop the water, bringing charges to the ground. You're relying on that in the first place. So if the, if the laser's just to help it out, to direct the lightning where it would have struck anyway, but now you strike to, strike it to your spot, your sweet spot, then you got a good farm going.

• 20:35Speaker 01

  I'm sorry, my what?

• 20:36Neil deGrasse Tyson?

  I just had to say, I had to just clarify all of that. Yeah. Oh, sorry.

• 20:41Speaker 01

  I, I need a moment. I think I need a cigarette. The man said my sweet spot.

• 20:48Speaker 01

  Who, uh, was our most scientifically friendly president? Like, which one of our US presidents was the most friendly to the field of science?

• 20:55Neil deGrasse Tyson?

  Ever?

• 20:56Speaker 01

  Ever?

• 20:56Neil deGrasse Tyson?

  Yeah, it depends on what you mean by friendly. In Washington, friendly means how much money do you give the enterprise? That's what, that's what, in Washington, all that matters is money. What you say doesn't matter at all.

• 21:07Speaker 01

  Okay.

• 21:07Neil deGrasse Tyson?

  Okay.

• 21:07Speaker 01

  But then let's go.

• 21:08Neil deGrasse Tyson?

  Just an FYI.

• 21:10Speaker 01

  Got you.

• 21:10Neil deGrasse Tyson?

  Okay. All right. So a few things. Uh, the, Abe Lincoln began the National Academy of Sciences. Now, that's kind of cool.

• 21:21Speaker 01

  Very.

• 21:22Neil deGrasse Tyson?

  It was set up to establish an advisory board to Congress that was not itself politically motivated for any reason. And so Congress would call on the National Academy of Sciences to produce studies on scientific issues that befall the day. I gotta put Lincoln at the top of that list.

• 21:41Speaker 01

  Okay.

• 21:42Neil deGrasse Tyson?

  As the most scientifically aware and literate.

• 21:45Speaker 01

  So he was not just a cat owner?

• 21:47Neil deGrasse Tyson?

  I didn't know he owned cats.

• 21:48Speaker 01

  He was the first president to have a cat?

• 21:49Neil deGrasse Tyson?

  I did not know. Why do you even know that?

• 21:51Speaker 01

  Because I was getting tired of the slavery thing. Like, what else did he do? How can we determine the difference between a brown dwarf and a large rogue planet?

• 22:00Neil deGrasse Tyson?

  Oh, it's hard. Uh, brown dwarf is a star that didn't make it, and a large rogue planet is just a big old chubby planet. There are astrophysical differences between the two, but they're very hard to notice from a distance. So it's very hard. It's one of the big challenges. And we got low-mass star people and high-mass planet people meeting in the dark of night, trying to solve that problem.

• 22:20Speaker 01

  You said chubby planet. Joshua Jenkins wants to know, why does the Earth spin in the direction it does? And what if Earth started spinning twice as fast as it does now?

• 22:31Neil deGrasse Tyson?

  Ooh, okay, so we spin this direction because, I'm gonna say it exactly physically, you ready?

• 22:36Speaker 01

  Yes.

• 22:36Neil deGrasse Tyson?

  That is the direction of the angular momentum of the entire solar system.

• 22:40Speaker 01

  So we're going with the flow?

• 22:42Neil deGrasse Tyson?

  Beautiful. We're going with the flow. The sun spins that way. All planets orbit that way. The moons orbit that way. Everybody is going counterclockwise as viewed from the top. Now, why do they want to spin up Earth? I don't know. That would have the length of the day. There would be 12-hour days instead of 24-hour days.

• 23:01Speaker 01

  Oh, I can't get enough done.

• 23:02Neil deGrasse Tyson?

  And the act of spinning us up, okay, we'll feel that. That would not be a good day on Earth. All right? Okay. You will know when Earth starts spinning faster. Well, you know what'll happen? Stuff behind you will run into you and you'll be flattened against it and you'll be a pile of goo on the wall behind you. That, because you, right now, you're moving 800 miles an hour with the rotation of the Earth. If you all of a sudden start going 1,600 miles an hour, something came in behind you to push you to do that and that will flatten you into a pile of goo.

• 23:35Neil deGrasse Tyson?

  Welcome back to StarTalk Radio and our season four Cosmic Queries Time Capsule. One of your favorites was an episode on the science of timekeeping, where the comedian Chuck Nice and I discussed nearly an infinity of timely topics.

• 23:51Speaker 03

  I've been hearing a lot about this theory, that if we place a giant mirror 22 light years away from, away, and point it at an extremely efficient telescope, we would see things happening in real time in the past. That's what he's saying. So I think what he's saying is, if you were to put a mirror 22 light years away from Earth, point it back at Earth, would you be able to see Earth 22 years in the past?

• 24:16Neil deGrasse Tyson?

  No, you would see it 44 years in the past.

• 24:19Speaker 03

  Right, because it's gotta go there and come back.

• 24:21Neil deGrasse Tyson?

  Do the math.

• 24:21Speaker 03

  Yeah, you gotta, you gotta look at it and then it's gotta come back to your eyes.

• 24:25Neil deGrasse Tyson?

  Exactly. So you see yourself in a mirror, not as you are, but as you once were, two billionths of a second ago.

• 24:31Speaker 03

  Gotcha.

• 24:31Neil deGrasse Tyson?

  If, if you're a foot away.

• 24:33Speaker 03

  If you're a foot away.

• 24:33Neil deGrasse Tyson?

  Light travels a foot every billionth of a second. Okay. One foot per nanosecond, if you want to be exact. We came up with the number 22, I don't know. Stick a mirror out there? Let the light go and come back. You will see however many light years away. Double that because it's the round trip time. That's how far in the past you were viewing events on earth.

• 24:53Speaker 03

  So you're viewing the events that they're out. You're actually looking at the past in real time for you.

• 25:00Neil deGrasse Tyson?

  Yes.

• 25:01Speaker 03

  Gotcha.

• 25:01Neil deGrasse Tyson?

  Yes.

• 25:02Speaker 03

  Gotcha.

• 25:02Neil deGrasse Tyson?

  That's exactly what's happening. That beam is on its way to the mirror and it's on its way back and you're catching it.

• 25:07Speaker 03

  Right.

• 25:07Neil deGrasse Tyson?

  Alright, that's all. And by the way, we see other objects in the past because their light has just reached it. So this is not magical thinking.

• 25:15Speaker 03

  Right.

• 25:15Neil deGrasse Tyson?

  My favorite is a galaxy that's sixty-five light years away. I'm sorry, sixty-five million light years away. It's a galaxy called M100.

• 25:23Speaker 03

  M100.

• 25:23Neil deGrasse Tyson?

  M100, sixty-five million light years away. And guess what they're seeing on earth right now if they had a telescope big enough?

• 25:31Speaker 03

  What?

• 25:32Neil deGrasse Tyson?

  The extinction of the dinosaurs.

• 25:33Speaker 03

  Look at that. That's so cool.

• 25:35Neil deGrasse Tyson?

  That beam of light that conveys the information that they got slammed is just now reaching them. Because they're sixty-five million light years away. And when did the dinosaurs go extinct on earth?

• 25:44Speaker 03

  Sixty-five million years ago.

• 25:46Neil deGrasse Tyson?

  You got it.

• 25:48Speaker 03

  Is the perception of time universal? Or do we all perceive time differently? I wonder if a housefly and other organisms perceive time to be quicker.

• 25:59Neil deGrasse Tyson?

  It's fun to think about other life forms that live shorter or longer as perceiving time differently. But typically when we do that, we are humanizing their life.

• 26:08Speaker 03

  Right.

• 26:09Neil deGrasse Tyson?

  So one dog year is seven.

• 26:12Speaker 03

  Seven human years.

• 26:13Neil deGrasse Tyson?

  Yeah, dogs don't care about humans.

• 26:16Neil deGrasse Tyson?

  So, but the passage of time as measured by the atomic vibrations of atoms within them is the same for everyone.

• 26:23Speaker 03

  Okay.

• 26:24Neil deGrasse Tyson?

  Oh, yeah.

• 26:24Speaker 03

  So that's it. On an atomic level, that's it.

• 26:27Neil deGrasse Tyson?

  That's it.

• 26:27Speaker 03

  No, no, no difference.

• 26:29Neil deGrasse Tyson?

  You can slow it down, speed it up with relativity, but otherwise, if you put the frog and the mayfly and the human and the elephant together in a room, the passage of time is the same.

• 26:38Speaker 03

  I got you. And that makes great sense for dogs because that means a dog would be licking its butt for about two months.

• 26:45Neil deGrasse Tyson?

  Total out of its life.

• 26:47Speaker 03

  How would a spacefaring people keep time?

• 26:51Neil deGrasse Tyson?

  Oh, that's good. Okay, just they-

• 26:53Speaker 03

  Real simple.

• 26:53Neil deGrasse Tyson?

  Look at their watch. No, there's an important- do you know, do you know what time it was on the moon?

• 26:59Speaker 03

  No.

• 26:59Neil deGrasse Tyson?

  It was Houston time.

• 27:01Speaker 03

  That's funny.

• 27:02Neil deGrasse Tyson?

  Right, because they're talking to Houston.

• 27:03Speaker 03

  That's so funny.

• 27:03Neil deGrasse Tyson?

  Houston's telling them when to wake up and go to sleep.

• 27:06Speaker 03

  Oh, my God, you're absolutely right.

• 27:07Neil deGrasse Tyson?

  You pick a spot on Earth-

• 27:08Speaker 03

  Right.

• 27:08Neil deGrasse Tyson?

  And that becomes your time-

• 27:09Speaker 03

  In space.

• 27:10Neil deGrasse Tyson?

  If you had an actual colony, space colony, that was nowhere near Earth-

• 27:14Speaker 03

  Right.

• 27:15Neil deGrasse Tyson?

  And you didn't care about Earth, then you're not dependent on the rotation of the Earth, or daylight or nighttime. You can create whatever kind of days you want. Studies in psychology showed that if you lock people away and had them set up their own cycles, that their day is typically 25 hours.

• 27:30Speaker 03

  Really?

• 27:31Neil deGrasse Tyson?

  Twenty-five and a half. That's why you never quite feel right, like the day is always a little bit ahead of you.

• 27:36Speaker 03

  Yeah.

• 27:36Neil deGrasse Tyson?

  It's because you really want a 25-hour-

• 27:38Speaker 03

  You need an extra hour.

• 27:38Neil deGrasse Tyson?

  You need an extra hour. You need an extra couple of hours.

• 27:40Speaker 03

  And I thought I was just hungover.

• 27:44Speaker 03

  If light can't escape a black hole, how would time be affected inside the black hole? So now you got a force that is stronger, that gravity is stronger than light itself.

• 27:57Neil deGrasse Tyson?

  As you fall into a black hole, time ticks more slowly for you. And you look out to the rest of the universe, and the rest of the universe goes by quickly. In fact, as you descend to that cosmic abyss, moments go by for you, and trillions of years go by for the universe itself. You will outlive the universe in your descent to the center of a black hole.

• 28:19Speaker 03

  Is the universe necessary for time to exist? For example, was time present within whatever came before the universe?

• 28:28Neil deGrasse Tyson?

  Time as we have defined it exists only within this universe.

• 28:31Speaker 03

  Got it.

• 28:31Neil deGrasse Tyson?

  If we go outside of our universe, we'll have to think up something else-

• 28:34Speaker 03

  Else.

• 28:35Neil deGrasse Tyson?

  -to keep track of things. Maybe there's some meta-time that we can think of, just the way we can think of a multiverse-

• 28:41Speaker 03

  Right.

• 28:41Neil deGrasse Tyson?

  A word bigger than the word universe itself. Maybe we are longing for that word, such as meta-time, that can accommodate our measuring needs when we exit this universe in which we're born.

• 28:58Neil deGrasse Tyson?

  Welcome back to StarTalk Radio. We're wrapping up our season four Cosmic Queries Time Capsule Show with the episode on viruses and pandemics. Journalist Laurie Garrett joined comedian Chuck Nice and me to answer your burning questions on SARS, HIV, and other spreading diseases.

• 29:18Neil deGrasse Tyson?

  Chris's point, of course, is if we can make viruses that we control that are sort of machine, machines, but are small like viruses, we can infect you with something that we manufactured in the lab.

• 29:31Speaker 02

  Well, there is nanotech that is targeting disease, and there is a lot of talk about...

• 29:37Neil deGrasse Tyson?

  That would be nanobots for good.

• 29:39Speaker 02

  Yes. The positive force of Marvel Comics or what have you. These nano agents, which are still very much in the, I would say, the front end of the research process, it is imagined would target, for example, killing cancer cells. So they would recognize something on the surface of the cell that said, "I'm a cancer cell," and then go in and kill it with a poison or what have you.

• 30:06Neil deGrasse Tyson?

  But in the hands of the diabolical evil genius.

• 30:11Speaker 02

  Well, the question really is to ask, is there a way to make a nanobot self-reproducing?

• 30:18Neil deGrasse Tyson?

  The way life would, the way a virus...

• 30:20Speaker 02

  If a nanobot could be self-reproducing, then indeed you could have an out-of-control infectious problem.

• 30:27Speaker 03

  Because it would have to replicate itself in order for that to happen, like a virus would do.

• 30:32Speaker 02

  Like a virus. The other thing that's going on now is that we have this dichotomy of purpose, where people in public health want to know what's going on with viruses in the natural world, so we're ready and we make our countermeasures, our vaccines and what have you. But on the other hand, there's a lot of folks that say, "Well, the best way to answer that question is to do man-made evolution. Let's direct the evolution of viruses in the lab, manipulate them, turn them into monster viruses, and see, you know, what does it take to be a monster virus?" So, last year, two different teams...

• 31:07Speaker 03

  You're scaring the crap out of me right now.

• 31:08Speaker 02

  I know. Well, last year, two different teams, one in Wisconsin and one in Rotterdam, indeed made a super killer form of flu. In the lab, and a whole lot of people said, why in the world would you do such a thing?

• 31:20Speaker 03

  Yes, why?

• 31:21Speaker 02

  And those are now sitting in freezers, right?

• 31:23Speaker 03

  We kept them!

• 31:24Speaker 02

  Last month, not to be outdone by Americans, because, you know, they don't want to be outdone by Americans with anything. The Chinese, a lab in Harbin, made 127 man-made flu viruses, of which five readily spread in the air between guinea pigs and killed them.

• 31:39Speaker 03

  Oh my god!

• 31:40Speaker 02

  So this is the new cusp that we're on, is, oh, we're trying to do it for good. We're trying to see in advance what nature might do. But in the process, you're putting in a freezer Armageddon.

• 31:52Neil deGrasse Tyson?

  People, and people were afraid of physicists, the biologists are the plum crazy.

• 31:56Speaker 03

  You are not lying, man. Oh my god!

• 31:59Neil deGrasse Tyson?

  I'll take an atom bomb any day over this.

• 32:02Speaker 03

  Yeah, I gotta tell ya, in the fraternity of science, you guys are Animal House.

• 32:07Speaker 02

  Well, if you don't like that, check this out.

• 32:09Neil deGrasse Tyson?

  No, stop there! No, no, no, no, you got something worse than that?

• 32:14Speaker 02

  Wait, wait, there's more!

• 32:16Neil deGrasse Tyson?

  You got 20 seconds, go!

• 32:17Speaker 02

  House Synthetic Biology, there's a competition called iGEM. In order to compete, high school students and college students have to make a novel, not pre-existing, microorganism. In 2012, there were 248 competing teams, meaning 248 previously nonexistent microbes, were made by high school and college students.

• 32:36Neil deGrasse Tyson?

  That's the end of, that's the end.

• 32:38Speaker 03

  It's the end of the world, right here, is what you just told us. What do you think is the most interesting historical plague or epidemic, viral or otherwise, and why is it so fascinating?

• 32:49Speaker 02

  Plague. It completely reshaped Europe forever.

• 32:52Neil deGrasse Tyson?

  The politics, the, the food?

• 32:54Speaker 02

  The culture, the, the status of the church, the...

• 32:56Neil deGrasse Tyson?

  Okay, which plague had many outbreaks? Which one especially?

• 32:59Speaker 02

  14th century.

• 33:00Neil deGrasse Tyson?

  The big one. Gotcha.

• 33:01Speaker 02

  The black plague.

• 33:01Speaker 03

  The black plague. Black death, black death.

• 33:03Neil deGrasse Tyson?

  Okay.

• 33:04Speaker 03

  Why's gotta be a black death?

• 33:06Neil deGrasse Tyson?

  Chuck, say that for another show, Chuck!

• 33:08Speaker 02

  People's skin turn black.

• 33:10Speaker 03

  Yeah, all of a sudden, that's a bad thing.

• 33:16Speaker 03

  In the case of viruses and vaccines, if a disease gets eradicated, okay? Will future generations still have to get vaccinated for those diseases?

• 33:26Speaker 02

  No.

• 33:27Speaker 03

  None.

• 33:27Neil deGrasse Tyson?

  Nice, good.

• 33:28Speaker 03

  Okay.

• 33:28Neil deGrasse Tyson?

  Oh, she's, she's getting the hang of this.

• 33:30Speaker 03

  She's good.

• 33:30Neil deGrasse Tyson?

  She's good. All right.

• 33:31Speaker 03

  So when it's just gone, it's all gone.

• 33:32Speaker 02

  AKA smallpox. We don't vaccinate anymore.

• 33:36Speaker 03

  Could pathogens be spread in the atmosphere? A recent study done by Georgia Tech researchers found that E. coli amongst a great deal of bacteria that formed a sort of bacterial sphere in the upper atmosphere.

• 33:49Speaker 02

  Yes, we now have proof that pathogens, particularly sporulating ones, can spread in clouds and rain down in locations far away.

• 33:57Speaker 03

  Oh, man, that is one time you do not want to make it rain.

• 34:00Neil deGrasse Tyson?

  Ooh, do you, do you stay inside when that happens?

• 34:02Speaker 02

  Well, you don't.

• 34:03Neil deGrasse Tyson?

  You don't drink rain.

• 34:03Speaker 02

  You don't know it's coming and you don't know it's there.

• 34:05Neil deGrasse Tyson?

  You don't know for nothing.

• 34:08Speaker 03

  What is the minimum size of a population that can support a viral infection? So in other words, uh, for, for the virus itself to, to be able to continue on its life, what's the minimum number of people you need in a community so it can spread and continue to be a virulent?

• 34:27Speaker 02

  In theory, one, if that, if it's a slow growing microbe and a slow replicating one, for the duration of your life, you can be the host for it.

• 34:37Speaker 03

  Gotcha. So in theory, you could just be a vi- I could be a virus of one, like, like the army.

• 34:41Neil deGrasse Tyson?

  You got it.

• 34:42Speaker 03

  Nice. Has the link between a chicken virus and obesity been proven?

• 34:50Speaker 02

  First time I ever heard there was a link between a chicken virus and obesity.

• 34:53Speaker 03

  I think that, uh, by chicken virus, he means like a whole chicken and eating one in a sitting.

• 35:00Neil deGrasse Tyson?

  You've been listening to StarTalk Radio, brought to you in part by a grant from the National Science Foundation. As always, I bid you to keep looking up.

• 35:36Neil deGrasse Tyson?

  You

• 37:16Neil deGrasse Tyson?

  The.

• 39:26Neil deGrasse Tyson?

  The.

• 41:41Speaker 02

  The.

• 43:51Speaker 02

  The.

• 48:11Speaker 02

  To keep looking up.