Cosmic Queries: Time-Keeping

It’s time for a new episode of Cosmic Queries, where Neil deGrasse Tyson answers fan questions about photons, tachyons, the speed of light, the physics of the universe and time itself.

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.

• 0:21Neil deGrasse Tyson?

  This is StarTalk. I'm your host Neil deGrasse Tyson. I'm an astrophysicist at the American Museum of Natural History here right here in New York City. And I also serve as Director of the Hayden Planetarium. We are Cosmic Queries, StarTalk after hours. I like to think of it. I would never do Cosmic Queries alone. I get Chuck Nice to join me.

• 0:46Speaker 01

  Yes.

• 0:46Neil deGrasse Tyson?

  Chuck Nice Comic.

• 0:48Speaker 01

  At Chuck Nice Comic, that's me. How are you Neil?

• 0:50Neil deGrasse Tyson?

  That's what they call you in the Twitterverse.

• 0:51Speaker 01

  In the Twitterverse. I love that word.

• 0:53Neil deGrasse Tyson?

  Isn't it great? I can put a verse on everything and it is, and we take ownership of it in the universe.

• 0:57Speaker 01

  There you go.

• 0:58Neil deGrasse Tyson?

  Yeah.

• 0:58Speaker 01

  Yes.

• 0:59Neil deGrasse Tyson?

  The Chuckaverse.

• 1:01Speaker 01

  God, that's scary. The Chuckaverse is scary.

• 1:05Neil deGrasse Tyson?

  And so, thanks for being on.

• 1:07Speaker 01

  Absolutely.

• 1:08Neil deGrasse Tyson?

  And you got a TV show where you just bust into people's homes?

• 1:11Speaker 01

  Yes.

• 1:11Neil deGrasse Tyson?

  That's crazy.

• 1:12Speaker 01

  I love it.

• 1:13Neil deGrasse Tyson?

  How did he even let you do that?

• 1:15Speaker 01

  You know, they, I ask myself that question every time I'm on it. Like, how did this happen? But yes, the show is called Home Strange Home and I pretty much invade the homes of unsuspecting people, show up with cameras and they take me on a tour of their weird wonderful house.

• 1:30Neil deGrasse Tyson?

  And you just talk about them.

• 1:31Speaker 01

  And we, and seriously, I do.

• 1:32Neil deGrasse Tyson?

  Home and Garden TV, that's my sister's favorite TV show.

• 1:35Speaker 01

  I love your sister.

• 1:37Neil deGrasse Tyson?

  I mean, her favorite TV network.

• 1:39Speaker 01

  TV network.

• 1:39Neil deGrasse Tyson?

  Yeah, she'll find you for sure.

• 1:41Speaker 01

  I love her.

• 1:41Neil deGrasse Tyson?

  So, we got questions. The topic today is on time.

• 1:45Speaker 01

  Time and timekeeping.

• 1:46Neil deGrasse Tyson?

  Time reckoning. And so, we solicited questions from the internet.

• 1:50Speaker 01

  Yep.

• 1:51Neil deGrasse Tyson?

  We've got our website, StarTalkRadio.net and we're at StarTalkRadio on Twitter.

• 1:57Speaker 01

  Right.

• 1:57Neil deGrasse Tyson?

  And we're in Google Plus and so...

• 2:01Speaker 01

  I got questions from all of those places, Twitter, Google Plus, Facebook.

• 2:04Neil deGrasse Tyson?

  Bring it on.

• 2:05Speaker 01

  And StarTalkRadio.net.

• 2:06Neil deGrasse Tyson?

  If I can answer, it's not, the point of this is not to stump me, it's just that if I have answers, I share them.

• 2:11Speaker 01

  Right.

• 2:12Neil deGrasse Tyson?

  And otherwise, I'll just say I have no clue.

• 2:13Speaker 01

  Okay, cool.

• 2:14Neil deGrasse Tyson?

  All right, good.

• 2:14Speaker 01

  So now, I have a question.

• 2:19Speaker 01

  And, okay, I, here's the question, alright, uh, is time infin- infinite? Okay, and so I'm gonna, this is Scott, and this is Millad. These two questions, one, is time infinite? And so I might as well ask Scott's question along with that, which is, what is time? And now, here's the third part of that. I believe, time doesn't exist. So.

• 2:49Neil deGrasse Tyson?

  So that's the.

• 2:49Speaker 01

  That's, that's the third part. I just wanna know if I'm right or wrong.

• 2:52Neil deGrasse Tyson?

  The theory according to Chuck, time does not exist.

• 2:54Speaker 01

  That's my theory, that's my personal theory, is that time doesn't exist. But the question is.

• 2:58Neil deGrasse Tyson?

  We have evolutionary theory, quantum theory, and Chuck's theory.

• 3:01Speaker 01

  Yes.

• 3:02Neil deGrasse Tyson?

  Just to put this in context. What you really mean is you have a hypothesis.

• 3:06Speaker 01

  I have a hypothesis.

• 3:07Neil deGrasse Tyson?

  Really exist.

• 3:08Speaker 01

  Yeah, cuz it's really not a theory.

• 3:10Neil deGrasse Tyson?

  Alright.

• 3:10Speaker 01

  I have a hypothesis that time does not exist.

• 3:12Neil deGrasse Tyson?

  Einstein described time as being defined to make motion look simple.

• 3:17Speaker 01

  Wow. That Einstein dude was kinda deep.

• 3:20Neil deGrasse Tyson?

  He was deep, he was deep. And, in physics, wha- what we really care about is not what is true. Yes, that's fun over a beer, but what we really care about is, how does the universe reveal itself to us in ways that we can calculate? And then, understand what we see and make predictions about what is yet to be tested. And so, so we're, we're, we're dependent on our interaction with the universe. And so, if time is a thing, if we can define it in a way to make motion look simple, we're, we're all over it.

• 3:51Speaker 01

  Right.

• 3:51Neil deGrasse Tyson?

  Alright, and so, uh, time is not infinite. Time as we have defined it, had a beginning. And that was the big bang.

• 3:57Speaker 01

  That was a big bang.

• 3:58Neil deGrasse Tyson?

  If it was infinite, it would've go to the infinite past.

• 4:00Speaker 01

  Correct.

• 4:01Neil deGrasse Tyson?

  But it has, there's a, there's a stopwatch that got started at the big bang. The birth of space, and time, matter and energy. Now, as far as we know, we're gonna expand forever into the future. And if that's the case, time is what we call semi-infinite. It's infinite in one direction, but not the other.

• 4:19Speaker 01

  Gotcha.

• 4:19Neil deGrasse Tyson?

  It's an actual math term, semi-infinite.

• 4:21Speaker 01

  Semi-infinite, right.

• 4:22Neil deGrasse Tyson?

  And so.

• 4:22Speaker 01

  It's like a number line.

• 4:23Neil deGrasse Tyson?

  No, like a number line.

• 4:24Speaker 01

  Like a number line.

• 4:25Neil deGrasse Tyson?

  You start at one point.

• 4:25Speaker 01

  You start at one point, and then boom, you just keep going.

• 4:27Neil deGrasse Tyson?

  Semi-infinite, half-infinite, like a semi-circle is half a circle.

• 4:30Speaker 01

  Right.

• 4:31Neil deGrasse Tyson?

  Yeah, semi-infinite, you're half-infinite.

• 4:34Neil deGrasse Tyson?

  Is that good?

• 4:34Speaker 01

  God, that sounds so counterintuitive. You are semi-infinite.

• 4:38Neil deGrasse Tyson?

  You are only half an infinity.

• 4:39Speaker 01

  Right, you're only half of infinity. It's like, that's, that's really cool.

• 4:42Neil deGrasse Tyson?

  And so, in that, as far as we know, time will continue going forward forevermore.

• 4:48Speaker 01

  Right.

• 4:48Neil deGrasse Tyson?

  And so there you have it now, now that Chuck theory, right along with quantum theory.

• 4:52Speaker 01

  My hypothesis, yes.

• 4:53Neil deGrasse Tyson?

  Yes, thank you. Is that time does not exist.

• 4:55Speaker 01

  It doesn't exist.

• 4:56Neil deGrasse Tyson?

  And what's your evidence for this?

• 4:57Speaker 01

  Okay, so what my, think of it this way. If there were absolutely nothing, then there would be nothing to measure, and therefore time wouldn't exist. That's, that's what I'm saying.

• 5:10Neil deGrasse Tyson?

  Oh, okay, so what you're saying is time is a construct of the places where there are things to measure it?

• 5:14Speaker 01

  Exactly. That's my point.

• 5:16Neil deGrasse Tyson?

  I'll give you that.

• 5:17Speaker 01

  Oh, really?

• 5:17Neil deGrasse Tyson?

  Yeah.

• 5:18Speaker 01

  I'm right?

• 5:18Neil deGrasse Tyson?

  No, why, why, okay.

• 5:20Speaker 01

  No, I'm, I'm going with, I'm right. I'm going, I'm going with Neil's.

• 5:24Neil deGrasse Tyson?

  Let me explain, I must explain.

• 5:26Speaker 01

  No, don't explain. It's too good. I love it too much. Yeah, I'm going everywhere now. Neil deGrasse Tyson said my, my hypothesis was right. So screw you, buddy. I can't wait to get to a beer tonight.

• 5:38Neil deGrasse Tyson?

  All right, no, so here it is.

• 5:39Speaker 01

  By the way, you know time doesn't exist, right?

• 5:41Neil deGrasse Tyson?

  All right, here it is. Uh, we measure time with phenomena that repeat.

• 5:47Speaker 01

  Right, okay.

• 5:48Neil deGrasse Tyson?

  Okay, the clock dial turns, the, well initially it was astronomical referencing. The sun.

• 5:53Speaker 01

  The sun goes around, I mean, earth goes around.

• 5:55Neil deGrasse Tyson?

  That's what we thought, so the sun would go around the earth, the moon goes around the earth, this sort of thing. And you'd keep, you'd reckon time in these ways. And then we found you could track time to a vibrating atom. Something's got to repeat.

• 6:07Speaker 01

  Right.

• 6:08Neil deGrasse Tyson?

  All right, to measure time. So you could pose the following comment, that we're, there, if there exists places where nothing repeats, then you cannot reckon the passage of time.

• 6:22Speaker 01

  Right.

• 6:22Neil deGrasse Tyson?

  And with any kind of reliability. Not only that, getting back to the Chuck hypothesis, you can imagine a universe, or perhaps outside of our universe, where there is no matter, there is no space, there is no energy. It's just that which is not those three.

• 6:44Speaker 01

  Right.

• 6:44Neil deGrasse Tyson?

  And if it's that which is not those three, and all three of those conspire to allow us to measure time with tools, then where there aren't those three, time would in fact have no meaning.

• 6:57Speaker 01

  Exactly.

• 6:58Neil deGrasse Tyson?

  That's exactly what you were thinking.

• 6:59Speaker 01

  That's what I'm thinking. Awesome. God.

• 7:03Neil deGrasse Tyson?

  Chuck, so I'll give you that Chuck.

• 7:05Speaker 01

  Yes.

• 7:05Neil deGrasse Tyson?

  But that doesn't mean it doesn't have meaning in our universe, but in some meta place.

• 7:09Speaker 01

  In some meta place, right?

• 7:10Neil deGrasse Tyson?

  You got it.

• 7:10Speaker 01

  Yeah.

• 7:11Neil deGrasse Tyson?

  I'll grant you that.

• 7:11Speaker 01

  Okay, now we're gonna have to take a break because I gotta tweet that right now. I'm tweeting right now as we speak. Neil deGrasse Tyson said that my theory about the non-existence of time.

• 7:22Neil deGrasse Tyson?

  It's getting to his head.

• 7:26Speaker 01

  Alright, okay.

• 7:28Speaker 01

  Okay, I wonder, do we have quite, uh, time?

• 7:30Neil deGrasse Tyson?

  Quick one, quick one.

• 7:31Speaker 01

  Quick question. How would a spacefaring people keep time?

• 7:35Neil deGrasse Tyson?

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

• 7:37Speaker 01

  Real simple.

• 7:38Neil deGrasse Tyson?

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

• 7:43Speaker 01

  No.

• 7:44Neil deGrasse Tyson?

  It was Houston time.

• 7:45Speaker 01

  That's funny.

• 7:46Neil deGrasse Tyson?

  Right, because they're talking to Houston.

• 7:47Speaker 01

  That's so funny.

• 7:48Neil deGrasse Tyson?

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

• 7:50Speaker 01

  Oh, my God, you're absolutely right.

• 7:51Neil deGrasse Tyson?

  You pick a spot on Earth.

• 7:52Speaker 01

  Right.

• 7:53Neil deGrasse Tyson?

  And that becomes your time.

• 7:54Speaker 01

  In space.

• 7:54Neil deGrasse Tyson?

  More on that when we come back to StarTalk Cosmic Query.

• 8:17Neil deGrasse Tyson?

  StarTalk Radio Cosmic Queries, I'm Neil deGrasse Tyson, your personal and private astrophysicist. And I've got in studio with me here in New York City, Chuck Nice.

• 8:29Speaker 01

  Yes.

• 8:29Neil deGrasse Tyson?

  Chuckie Baby.

• 8:30Speaker 01

  How are you, man?

• 8:31Neil deGrasse Tyson?

  Good. Chuck Nice Comic, you tweet by.

• 8:33Speaker 01

  That's right, that's right.

• 8:34Neil deGrasse Tyson?

  Yeah, so you've been dropping questions in my lap, and that last one was a good one. I have more to add to it.

• 8:39Speaker 01

  Yeah, the, the question really simple was, simply was, how would a spacefaring people keep time?

• 8:44Neil deGrasse Tyson?

  Yeah, and, and so the good one, my favorite example of that is the Apollo astronauts that went to the moon. Who are they talking to?

• 8:52Speaker 01

  Talking to mission controller Houston.

• 8:53Neil deGrasse Tyson?

  And Houston, it's Houston time.

• 8:55Speaker 01

  It's Houston time. That's hilarious.

• 8:57Neil deGrasse Tyson?

  They just say hello, Pakistan, you know, what, you know, they, uh, that, so they kept time, they, they kept Houston time. And the, on Mars, like, what?

• 9:07Speaker 01

  The rover.

• 9:08Neil deGrasse Tyson?

  Right, Mars actually has its own clock, which is slightly different from Earth clock. The Mars Day is slightly longer than Earth Day. Okay. All right, and so that matters because the rovers that are there need sunlight to drive their solar panels. And so Mars professionals who study Mars keep a wristwatch that is Mars time and not Earth time. And they slowly migrate out of phase from one another. And yeah, because they don't, if you don't match perfectly, you slowly. Slowly, right. You slowly migrate. You drop out of phase. You drop out of phase. And so astronomers on Earth studying Mars are on Mars time. With sunrise and sunset at the location of the rover that they're studying. That's cool. That's very cool.

• 9:51Neil deGrasse Tyson?

  Yeah, yeah, and on the International Space Station, each module is put up by a different, is supported by a different country, country and nationality. Their time is the time, but from their, from their home base. So the Russian capsule is like Moscow time, right, on New York time. There's five different time zones on the International Space Station. The International Space Station. Ah, that's cool. And here's the question of all questions. If a time zone is separated by sort of degrees of longitude, right? Every 15 degrees, multiply 15 by 24, what do you get? Oh, God, I couldn't do that. This would not take God to answer.

• 10:28Neil deGrasse Tyson?

  It just takes the times table.

• 10:31Neil deGrasse Tyson?

  So let me see, that's 240 plus 5 times 24. Yes. So it's 120, so 240 and 120. So that's. Nice, Chuck, gets it, it comes in at 360. Yeah. So all 360 degrees of the Earth are split into 24 time zones, basically at 15 degrees of width, right? So as you crawl east-west, you can change your time zone. As you come near the poles, the time zones get narrower and narrower and narrower. And on the pole, every single time zone converges. So what time does Santa keep on his watch? I'm gonna say pole time. Pole time.

• 11:18Neil deGrasse Tyson?

  There's hammer time, now we got pole time. Yeah, you'd have to invent some, there is no day. There's six, there's six months of sunlight, six months of dark. The concept of a rotating Earth loses meaning on the pole where there are no time zones. That's weird, that's great. Yeah. Very cool. What else you got? All right, let's move on here.

• 11:41Speaker 01

  Okay, that's a, this is a good one.

• 11:43Neil deGrasse Tyson?

  Oh, by the way, oh, I gotta add one other thing. If you had an actual colony, space colony, that was nowhere near Earth, 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.

• 12:05Speaker 01

  Really?

• 12:05Neil 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.

• 12:10Speaker 01

  Yeah.

• 12:11Neil deGrasse Tyson?

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

• 12:13Speaker 01

  You need an extra hour.

• 12:14Neil deGrasse Tyson?

  You need an extra couple of hours.

• 12:15Speaker 01

  And I thought I was just hungover. Um, okay. Uh, here is-

• 12:21Neil deGrasse Tyson?

  Long ago, Earth's day was longer than it is today. We, yeah, we've been, we've been slowing down.

• 12:27Speaker 01

  Okay, because of the rotation?

• 12:28Neil deGrasse Tyson?

  Yeah, did I say longer? I'm sorry, I missed it. We had a faster day.

• 12:30Speaker 01

  Faster day.

• 12:31Neil deGrasse Tyson?

  Yeah.

• 12:31Speaker 01

  Gotcha.

• 12:31Neil deGrasse Tyson?

  Okay, but go on.

• 12:32Speaker 01

  Okay, so now here, I don't understand this question, and you're gonna have to get, take me to school on this one. Summarize the timelessness of a photon.

• 12:41Neil deGrasse Tyson?

  Oh, beautiful. That is beautiful. Are you ready?

• 12:45Speaker 01

  I'm ready.

• 12:45Neil deGrasse Tyson?

  Are you ready?

• 12:46Speaker 01

  I'm ready for this.

• 12:47Neil deGrasse Tyson?

  No, you're not ready. I don't think you're ready.

• 12:48Speaker 01

  You sound like Beyonce.

• 12:50Neil deGrasse Tyson?

  I don't think you're-

• 12:51Speaker 01

  Are you ready for this? Okay.

• 12:52Neil deGrasse Tyson?

  Are you ready for this?

• 12:53Speaker 01

  Tell me, are you ready? I'm ready.

• 12:55Neil deGrasse Tyson?

  Uh, I, no, you're not-

• 12:57Speaker 01

  I'm not ready?

• 12:57Neil deGrasse Tyson?

  No, tell me again.

• 12:58Speaker 01

  Okay, I'm ready.

• 12:59Neil deGrasse Tyson?

  Good. All right. Uh, you should know, if you study, uh, relativity, Einstein's relativity-

• 13:06Speaker 01

  Right.

• 13:06Neil deGrasse Tyson?

  That as you increase your speed, time ticks more slowly for you than it does for anyone who's watching you.

• 13:13Speaker 01

  Right.

• 13:13Neil deGrasse Tyson?

  All right? This is the relativity of time. And this is well-known, we've measured this. This is not, it's, it's not just your clock that's ticking slower. Your metabolism is unfolding more, more slowly. Your brain synapses firing more slowly. Everything about you is slowing down. All right, as you travel faster and faster, get closer and closer to the speed of light, you age more and more and more slowly. Time ticks more and more slowly for you.

• 13:40Speaker 01

  Okay.

• 13:41Neil deGrasse Tyson?

  If you hit the speed of light, which we don't know how to do yet, but if you ever hit the speed of light, then time stops.

• 13:51Speaker 01

  Stops.

• 13:53Neil deGrasse Tyson?

  Photons, which is the carrier of light.

• 13:57Speaker 01

  Light, right.

• 13:58Neil deGrasse Tyson?

  Exists at the speed of light. It doesn't accelerate from zero to speed of light in 3.4 seconds.

• 14:05Speaker 01

  Correct.

• 14:06Neil deGrasse Tyson?

  It exists at the speed of light, and because it exists at the speed of light, any watch that it's carrying

• 14:13Speaker 01

  Never ticks.

• 14:15Neil deGrasse Tyson?

  Which means if you are the photon, become the photon, if you are, and this is not a proton now.

• 14:22Speaker 01

  Right.

• 14:22Neil deGrasse Tyson?

  Particle in the nucleus of an atom.

• 14:24Speaker 01

  Right.

• 14:24Neil deGrasse Tyson?

  Photon, the particle of light.

• 14:26Speaker 01

  Light.

• 14:27Neil deGrasse Tyson?

  If you are a photon and you are emitted from across the universe.

• 14:31Speaker 01

  Right.

• 14:31Neil deGrasse Tyson?

  You will be absorbed, you will slam into whatever you are destined to hit, as far as you are concerned.

• 14:40Speaker 01

  Instantaneously.

• 14:41Neil deGrasse Tyson?

  That's correct.

• 14:42Speaker 01

  Right.

• 14:42Neil deGrasse Tyson?

  Because no time would have.

• 14:43Speaker 01

  Because no time's great, because you can't, because at that speed where you exist, that speed, time has stopped.

• 14:50Neil deGrasse Tyson?

  It stopped.

• 14:51Speaker 01

  So for you, time doesn't exist.

• 14:52Neil deGrasse Tyson?

  Time does not exist.

• 14:54Speaker 01

  Dude, this is mind blowing.

• 14:55Neil deGrasse Tyson?

  Time does not exist.

• 14:56Speaker 01

  Ah, yo, man.

• 14:57Neil deGrasse Tyson?

  Okay, now here's now.

• 14:58Speaker 01

  Now, wait a minute, you gotta give me a second, man.

• 14:59Neil deGrasse Tyson?

  You gotta absorb that.

• 15:00Speaker 01

  Nah, that was great.

• 15:01Neil deGrasse Tyson?

  Now, now.

• 15:02Speaker 01

  Yo, anybody got some weed? I need some weed right now, because that was cool.

• 15:07Neil deGrasse Tyson?

  Uh, some people would have requested it in advance of this. Uh, let's all move to Colorado and get the weed, right?

• 15:13Speaker 01

  Exactly.

• 15:13Neil deGrasse Tyson?

  So, so, um, so it's why we knew that the neutrino could not be traveling at the speed of light, because the neutrino actually changes species midway.

• 15:28Speaker 01

  Got you.

• 15:29Neil deGrasse Tyson?

  There's one kind of neutrino that can become a different kind of neutrino species. How would it know to do that? Unless it's keeping track of time?

• 15:36Speaker 01

  Exactly.

• 15:38Neil deGrasse Tyson?

  It knew to do this. It does that at a predictable interval. It can only do that if it's carrying a stopwatch.

• 15:45Speaker 01

  Wow.

• 15:45Neil deGrasse Tyson?

  So we knew the neutrinos were not traveling at the speed of light. Because if they were, they would never change.

• 15:49Speaker 01

  Wow.

• 15:50Neil deGrasse Tyson?

  They would not know to change.

• 15:51Speaker 01

  This begs the question, uh, uh, I'm gonna take, um, Todd Smith's question one step further.

• 15:59Speaker 01

  So if you surpass the speed of light, does time go backwards?

• 16:04Neil deGrasse Tyson?

  Yes.

• 16:05Speaker 01

  No! No!

• 16:07Neil deGrasse Tyson?

  Yes.

• 16:08Speaker 01

  Get out of here, man.

• 16:08Neil deGrasse Tyson?

  And the, the, we invented a, a particle that we would call, if we found a particle that did that, we have a name for it, they're called tachyons. From, from the Greek root for the tachometer comes from that.

• 16:20Speaker 01

  Yes.

• 16:20Neil deGrasse Tyson?

  It means fast.

• 16:21Speaker 01

  Right.

• 16:22Neil deGrasse Tyson?

  Okay, and so these, this proposed species of particles only ever exists faster than light. And they can travel infinitely fast, they would go backwards in time. If I sent you a tachyon signal, you would get it before I sent it.

• 16:36Speaker 01

  Before you sent it to me.

• 16:37Neil deGrasse Tyson?

  Correct.

• 16:39Neil deGrasse Tyson?

  Imagine messing with the tachyon and say, "Oh, it's fake."

• 16:43Neil deGrasse Tyson?

  Never mind. It's like, "Oh, gee, what are we gonna do?"

• 16:46Speaker 01

  Wow.

• 16:47Neil deGrasse Tyson?

  Yeah, so tachyons travel faster than light and move backwards in time. And it's perfectly consistent with Einstein's relativity. We're cool with that. We just never found them before.

• 16:55Speaker 01

  Awesome.

• 16:55Neil deGrasse Tyson?

  We don't know if they exist, but it works on paper.

• 16:58Speaker 01

  All right, all right. Okay.

• 17:00Neil deGrasse Tyson?

  I have one more question before this.

• 17:02Speaker 01

  Okay, really quick. Mark Swift, why hasn't time been decimalized?

• 17:06Neil deGrasse Tyson?

  Ooh, it was decimalized.

• 17:08Speaker 01

  What?

• 17:08Neil deGrasse Tyson?

  Yes, in the French Revolution. Did you know that they had decimal time in the French, the French, did you know that the, the metric system is conjoined with the French Revolution?

• 17:21Speaker 01

  I did not know that.

• 17:22Neil deGrasse Tyson?

  The French said, "As long as we're taking stuff up, let's fix this crap, these fractions." This stuff that came out of England with the, with the pints and the courts and the this and the, and the fifth and the dram and

• 17:34Speaker 01

  Right.

• 17:35Neil deGrasse Tyson?

  all of this. So they decimalized everything. And they got a little carried away because they wanted to decimalize time. So they turned a day into 10 hours, an hour into 100 minutes, and a minute into 100 seconds. That's correct.

• 17:50Speaker 01

  So that, so under that, you get a 10-hour day?

• 17:52Neil deGrasse Tyson?

  Yeah, it's a 10-hour day. So it's, they decimalize time, and if you do it right, if, if you, if you do the math, the number of seconds in a decimalized day is about the same, like within 10% of the number of seconds in a, in a normal day.

• 18:06Speaker 01

  Right.

• 18:06Neil deGrasse Tyson?

  So you wouldn't have to change, do much to. redefine the second, you just have to get people accustomed to decimalize hours and and minutes and

• 18:14Speaker 01

  Right.

• 18:14Neil deGrasse Tyson?

  And so, uh, but it failed, it failed. The, the meter stuck and other things stuck, but not decimal time.

• 18:21Speaker 01

  Look at that.

• 18:22Neil deGrasse Tyson?

  And I like my base sixty, my sexajecimal, uh, time from the Babylonians. They, what do you got against sixty? We are StarTalk Radio. When we come back, more cosmic queries.

• 18:51Neil deGrasse Tyson?

  This is StarTalk. I'm Neil deGrasse Tyson, your personal and private astrophysicist. In studio here in New York City with Chuck Nice.

• 19:00Speaker 01

  Yes.

• 19:01Neil deGrasse Tyson?

  You're with me on my cosmic queries part of the show.

• 19:04Speaker 01

  That's right.

• 19:05Neil deGrasse Tyson?

  You've called questions from the internet.

• 19:07Speaker 01

  Yes, sir.

• 19:07Neil deGrasse Tyson?

  From our website at starTalkRadio.net and on Twitterverse at StarTalkRadio. Where else? Google Plus? I think we're everywhere.

• 19:15Speaker 01

  Yeah, we got Google Plus.

• 19:16Neil deGrasse Tyson?

  Name it.

• 19:17Speaker 01

  We got Facebook, you name it.

• 19:18Neil deGrasse Tyson?

  Name it, we're there.

• 19:19Speaker 01

  Pinterest, YouTube. I mean, we're not taking questions from there, but we're still there.

• 19:23Neil deGrasse Tyson?

  We're still working it.

• 19:23Speaker 01

  Yeah.

• 19:24Neil deGrasse Tyson?

  All right. So what do you got for me?

• 19:25Speaker 01

  All right.

• 19:25Neil deGrasse Tyson?

  At least we're talking about time reckoning, I guess. Yeah.

• 19:28Speaker 01

  Yeah. So I think, um, all right, here's a funny question. So this is from Jeff Sloan. And Jeff says, just an interesting thought that I had that I would like you to explore or completely debunk. If objects moving faster than the speed of sound can cause a sonic boom, is it at all possible that the big bang was a result of something traveling faster than the speed of light? If I'm correct, please provide an address where I can pick up my Nobel Peace Prize.

• 19:55Neil deGrasse Tyson?

  Okay. First of all, the Peace Prize is not given for discoveries in physics. That would be the Nobel Physics Prize.

• 20:02Speaker 01

  Aha.

• 20:04Neil deGrasse Tyson?

  Just to clarify that.

• 20:05Speaker 01

  There you go, Jeff. Sorry, buddy. No Peace Prize for you, no matter what.

• 20:09Neil deGrasse Tyson?

  No matter what. Uh, occasionally a scientist can win a Peace Prize, but it's rare. It usually goes to a politician in power.

• 20:17Speaker 01

  Right.

• 20:17Neil deGrasse Tyson?

  Or a dissident in power.

• 20:19Speaker 01

  Right.

• 20:19Neil deGrasse Tyson?

  Right. Uh, so, so what do you want? So he wants to know if you can get a sonic boom, a light boom. Yes.

• 20:26Speaker 01

  Basically a light boom is what he's talking about.

• 20:27Neil deGrasse Tyson?

  The answer is yes. It's called Shereinkov radiation. Dude, you are killing me. Yeah, yes. If you go travel, if you travel faster than light, there is the light equivalent to a sonic boom. Where the light pulse gets, gets, um, bu- builds up on itself and it's a flash of light. And it's called Cherenkov radiation. Now, but since you can never travel faster than light. Right. You might ask, how does one come up with this stuff? Exactly. Here's how it works. If you have light traveling through water, transparent water. Light travels slower through water than through a vacuum. It travels, so, so let's start, it's fastest in a vacuum. Right. Chao's a little slower going through air. Right.

• 21:11Neil deGrasse Tyson?

  Chao's a little slower going through water. Right. Chao's even slower going through glass. Chao's even slower going through diamond. Okay, and that, and of course, that is because it is both a wave and a particle. Yeah, it's trying to get through the medium. Through the medium. Trying to get through them. And in fact, the diamond, I've remembered my number, it's forty percent as fast in a diamond as in a vacuum. Wow. Yes, it's, it's slow. Huge difference. That's what makes diamonds so cool. So if you put facets in the diamond at the right angles. Right. At the correct angles, because a right angle would be ninety degrees. At the correct angles, they, because what we call the index of refraction is so large. Mm-hmm. Because light travels so slowly in a diamond, that it bends back on itself multiple times

• 21:53Neil deGrasse Tyson?

  within the angles that you can create on your ring, and then it shows up again in a different direction. So that's why the diamond looks like it sparkles. Because if it was only light coming from where the light came from, you say, well, that's just the light I'm looking at. But if it comes from a new angle, you say, hey, that diamond is sparkling, is talking to me. Right. So, alright, so now, you have light going through all these media. Now you send a particle through there faster than that speed. Mm-hmm. That will create a mini sonic boom, except it's not sound, it's light, a mini light boom. And it was first described by, uh, the physicist named Cherenkov, and he won a Nobel Prize for this discovery. Look at that. The Cherenkov, so, so tell them the Nobel Prize has already been claimed. It's already been, sorry Jeff, your, your prize has been claimed. Okay.

• 22:38Neil deGrasse Tyson?

  You were right, but somebody beat. Wait, wait, but let me get back to the Big Bang. So the Big Bang was an expansion of the universe faster than light, but it's not the universe expanding faster than light in a medium.

• 22:50Speaker 01

  Gotcha.

• 22:51Neil deGrasse Tyson?

  It is the very fabric of space and time itself expanding, and you don't get Cherenkov radiation for that.

• 22:56Speaker 01

  From that, okay, right, because it's actually happening in the vacuum, which is space.

• 23:01Neil deGrasse Tyson?

  Well, no, I mean, all of space is the explosion. It's not a vacuum within the space.

• 23:04Speaker 01

  Okay, so the space itself is the explosion.

• 23:06Neil deGrasse Tyson?

  Is the explosion, exactly.

• 23:07Speaker 01

  Gotcha, gotcha.

• 23:08Neil deGrasse Tyson?

  Duh.

• 23:09Speaker 01

  Look at that. Yeah, that's true. That's awesome.

• 23:11Neil deGrasse Tyson?

  Okay.

• 23:12Speaker 01

  All right. All right, let's move on. Okay, I love this question, too. This is Theo Potter. What would actually happen to the planet if Superman made the world spin in the opposite direction like in the 1978 movie? I'm assuming our gravity would shift and time would not rewind.

• 23:33Neil deGrasse Tyson?

  Okay.

• 23:34Speaker 01

  So now, let's just say, for instance, you can spin the Earth backwards.

• 23:39Neil deGrasse Tyson?

  Okay.

• 23:39Speaker 01

  What are the results?

• 23:40Neil deGrasse Tyson?

  All right, so while Superman was flying around the Earth the opposite way, and we saw the Earth slow down.

• 23:47Speaker 01

  Mm-hmm.

• 23:47Neil deGrasse Tyson?

  Well, okay, the Earth is going, if you're at the equator, you're moving 1,000 miles an hour on the rotation path that the Earth brings you. If you slow down from 1,000 miles an hour to zero, uh, excuse me, if you're not wearing a seatbelt connected to Earth, you're gonna fall over and do, and roll due east at 1,000 miles an hour.

• 24:06Speaker 01

  So you mean the whole Earth, everything on it?

• 24:08Neil deGrasse Tyson?

  Everything on Earth is not bolted, would, would fall over and roll due east.

• 24:12Speaker 01

  Right.

• 24:13Neil deGrasse Tyson?

  Commensurate with the speed that it had going east-west at the beginning of this. Santa would be fine.

• 24:18Speaker 01

  Right, because he's, he's up on pole time.

• 24:20Neil deGrasse Tyson?

  On pole time.

• 24:20Speaker 01

  And he's chilling.

• 24:21Neil deGrasse Tyson?

  He's chilling on pole time. So, so everyone would just fall over, and then he'd like stopped Earth, and then spun it back, and you'd fall, but you'd roll back the other way. So we'd be completely battered from this process, and nothing would have happened to time, and our gravity would remain exactly the same.

• 24:37Speaker 01

  So basically, nothing would have happened to time, nothing happens to gravity, we're just in a huge planetary auto accident.

• 24:45Neil deGrasse Tyson?

  Auto accident, a train wreck of an auto accident, yes. And, and, so, right, right, that, that, that. Now, by the way, you're a little lighter on the equator because of the centrifugal force of the rotating Earth, but not enough that's gonna matter. You're a couple of ounces lighter. So they first stopped turning, you'd be just a little heavier, but nothing that anyone would notice.

• 25:04Speaker 01

  Okay.

• 25:05Neil deGrasse Tyson?

  We gotta come back to StarTalk. Cosmic Queries with Chuck Nice. We'll see you in a moment.

• 25:28Neil deGrasse Tyson?

  We're back on StarTalk Radio, Cosmic Queries. I'm Neil deGrasse Tyson, your home astrophysicist, with Chuck Nice.

• 25:37Speaker 01

  Yes.

• 25:37Neil deGrasse Tyson?

  Chucky Baby tweeting at ChuckNiceComic.

• 25:40Speaker 01

  That's correct.

• 25:40Neil deGrasse Tyson?

  Yeah, so we at the intermission, we were talking about Superman's feet.

• 25:46Speaker 01

  Right.

• 25:47Neil deGrasse Tyson?

  Not his feet, but...

• 25:49Speaker 01

  His feet of spinning the Earth backwards.

• 25:51Neil deGrasse Tyson?

  Thank you, not his anatomical feet. He spun the Earth backwards reversing time.

• 25:56Speaker 01

  So Theo Potter had said, you know, wanted to know what would happen if the Earth actually went backwards, and you answered that. But Clarissa Wegner actually says, @Theo, "I think what happened was that Superman didn't reverse the spin of the Earth. He was just going so fast that he himself went back into time and was able to do whatever he had to do."

• 26:21Neil deGrasse Tyson?

  Oh, okay.

• 26:23Speaker 01

  So not the Earth spun backwards, he went backwards into time.

• 26:28Neil deGrasse Tyson?

  Okay, so this is who?

• 26:29Speaker 01

  Now, this is Clarissa.

• 26:30Neil deGrasse Tyson?

  So Clarissa is talking to Theo, and we ain't even in that conversation?

• 26:34Speaker 01

  They are having their own conversation.

• 26:36Neil deGrasse Tyson?

  Yeah, I'm sorry, Theo, I didn't get to your answer fast enough. We've got other readers jumping in on it. So I remember when I saw that movie, because my girlfriend at the time, you know, I'm people's own astrophysicist, right? So they asked me the questions. So she said, "Could that really happen?" she asked. At no time else in that movie did she ask me if what she saw could actually happen. Like, could a man in blue pantyhose fly? That question did not come up. Can he block bullets off his chest? That question did not come up.

• 27:08Speaker 01

  Right.

• 27:08Neil deGrasse Tyson?

  But can he go back in time? That came up. So, could he have been taking himself back in time? But why would we watch Earth slow down, stop, and... Reverse, you can't go back in time yourself.

• 27:22Speaker 01

  Okay.

• 27:23Neil deGrasse Tyson?

  And well, hmm, unless back in time, we are revisiting the earth at that rotational phase. Okay, I'm, I'm, now that I think about it.

• 27:33Speaker 01

  Yeah.

• 27:34Neil deGrasse Tyson?

  I can let that go.

• 27:35Speaker 01

  We, we, so Clarissa has some legs here?

• 27:37Neil deGrasse Tyson?

  He is not turning earth backwards.

• 27:40Speaker 01

  Right.

• 27:40Neil deGrasse Tyson?

  He is going back in time, rewinding the clock.

• 27:44Speaker 01

  Right.

• 27:45Neil deGrasse Tyson?

  So earth didn't actually stop.

• 27:47Speaker 01

  Right. That's what she, that's what Clarissa is saying.

• 27:49Neil deGrasse Tyson?

  I gotta give her that. Clarissa.

• 27:51Speaker 01

  Clarissa's on to something.

• 27:52Neil deGrasse Tyson?

  Clarissa, you're on to something.

• 27:53Speaker 01

  Look at that.

• 27:54Neil deGrasse Tyson?

  I'll give you that. Okay. Now, why she would do that for Lois Lane, that's a bigger question.

• 28:02Speaker 01

  Oh, that's rough.

• 28:02Neil deGrasse Tyson?

  Sorry, sorry.

• 28:03Speaker 01

  Cold blooded. Okay.

• 28:07Speaker 01

  That was.

• 28:07Neil deGrasse Tyson?

  No, we need Lois. We need Lois. Sorry.

• 28:10Speaker 01

  All right, cool.

• 28:11Neil deGrasse Tyson?

  Plus, I met Superman in the comic. You, you didn't see this comic. I was in the comic. I was in the Superman comic. Me and Superman were chilling.

• 28:18Speaker 01

  Yeah, man, I think that's so cool.

• 28:20Neil deGrasse Tyson?

  But Lois Lane was not there. I didn't meet Lois Lane. Maybe I feel differently about her if I got to know her as a person.

• 28:25Speaker 01

  You know, I'm just glad that you didn't meet her because that would have been awkward.

• 28:29Speaker 01

  All right, here we go.

• 28:30Neil deGrasse Tyson?

  Yeah.

• 28:30Speaker 01

  Um, I've been hearing a lot about this. This is from Jordan Navarro. 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. He, his, so since the mirror is 22 light years away, wouldn't it still take that light 22 years to travel back to the mirror? 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?

• 29:12Neil deGrasse Tyson?

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

• 29:16Neil deGrasse Tyson?

  Right, because it's gotta go there and come back. Do the math. Yeah, you gotta, you gotta look at it and then it's gotta come back to your eyes. Exactly. So you see yourself in a mirror, not as you are, but as you once were, two billionths of a second ago. Gotcha. If, if you're a foot away. If you're a foot away. 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. I'd. 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. So you're viewing the events that they're out, you're actually looking at the past in real time for you? Yes. Gotcha. Yes. Gotcha.

• 29:58Neil 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. Right. 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. Right. My favorite is a galaxy that's 65 light years away. I'm sorry, 65 million light years away. It's a galaxy called M100. M100. M100, 65 million light years away. And guess what they're seeing on Earth right now if they had a telescope big enough? What? The extinction of the dinosaurs. Look at that, that's so cool. That beam of light that conveys the information that they got slammed is just now reaching them. It's just reaching them. Because they're 65 million light years away. And when did the dinosaurs go extinct on Earth?

• 30:41Neil deGrasse Tyson?

  65 million years ago. You got it. You're listening to StarTalk Radio. We'll be back in a moment. More with Chuck Nice. I'm Neil deGrasse Tyson for Cosmic Queries.

• 31:12Neil deGrasse Tyson?

  We're back on StarTalk Radio. I'm Neil deGrasse Tyson with Chuck Nice. Yes. Chuck Nice, comedian. Yes, sir. Yes, sir. Well, that'd be female comedian. I was gonna say, well, you know, I'm a little both. A little both. I'm a little both. I'm like a little country and a little rock and roll. Alright, there you go. Thanks for being here. I couldn't do this without you. You're reading questions to me from the internet and all our internet presence. And this is our last segment. We have, we didn't, we hardly got through any of these questions.

• 31:39Speaker 01

  Yeah, so you know, we, we got through a goodly amount, but uh, you know what? Because we're gonna try to get to as many as possible now, we're gonna call this our lightning round.

• 31:46Neil deGrasse Tyson?

  Lightning round. So now you want me to answer fast?

• 31:48Speaker 01

  It's just, yeah, you know, well, you know, if we get to it, we get to it.

• 31:51Neil deGrasse Tyson?

  All right, I'll try, I'll try, all right.

• 31:53Speaker 01

  So let's jump right into it here. We got uh,

• 31:55Neil deGrasse Tyson?

  The lightning round.

• 31:55Speaker 01

  The lightning round.

• 31:56Neil deGrasse Tyson?

  I need a bell.

• 31:58Speaker 01

  Steven Castaneda says, 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. So shorter lifespan, shorter time span, I mean, do you, so you know what I mean, like?

• 32:19Neil 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.

• 32:28Speaker 01

  Right.

• 32:28Neil deGrasse Tyson?

  So one dog year is,

• 32:31Speaker 01

  Seven human years?

• 32:32Neil deGrasse Tyson?

  Yeah, dogs don't care about humans.

• 32:36Neil deGrasse Tyson?

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

• 32:44Speaker 01

  Okay.

• 32:44Neil deGrasse Tyson?

  Oh yeah.

• 32:45Speaker 01

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

• 32:47Neil deGrasse Tyson?

  That's it.

• 32:48Speaker 01

  No, no, no difference.

• 32:49Neil deGrasse Tyson?

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

• 32:59Speaker 01

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

• 33:05Neil deGrasse Tyson?

  Total out of its life. If it were a human, yeah.

• 33:08Speaker 01

  Okay, here we go.

• 33:09Neil deGrasse Tyson?

  Keep going.

• 33:09Speaker 01

  Uh, Samir Schuman, would time exist without motion?

• 33:15Neil deGrasse Tyson?

  No. Next question.

• 33:17Speaker 01

  Oh crap.

• 33:18Neil deGrasse Tyson?

  It could exist, you could never measure it.

• 33:19Speaker 01

  Gotcha.

• 33:20Neil deGrasse Tyson?

  And not only that, you'd have to be able to measure it with motion that repeats. If it's motion that's non-repeats, you'd have no real way to measure it.

• 33:27Speaker 01

  Okay, all right.

• 33:28Neil deGrasse Tyson?

  Got it. Next.

• 33:29Speaker 01

  Here is Tom Schilson, and Tom Schilson asks, is there any evidence?

• 33:35Neil deGrasse Tyson?

  No. Next.

• 33:38Neil deGrasse Tyson?

  What's the lightning round?

• 33:39Speaker 01

  You're good at this.

• 33:40Neil deGrasse Tyson?

  Oh, man, man.

• 33:40Speaker 01

  Okay, no. Is there any evidence that time is broken into little bits? Now, this guy's, he's going on some space-time continuum trip now, man. So here's what Tom says. Is, is time, can time be broken into little bits?

• 33:55Neil deGrasse Tyson?

  Yes.

• 33:55Speaker 01

  What?

• 33:56Neil deGrasse Tyson?

  Yes. I, I said no, but the answer is yes. All of our understanding of the nature of reality

• 34:02Speaker 01

  Mm-hmm.

• 34:03Neil deGrasse Tyson?

  Tell us that time is quantized on the smallest scales. It is quantized. So that time, it does not pass continuously, but there's the smallest possible unit of time you can measure, and you need quantum physics to recognize that. So, yes. Time gets quantized.

• 34:22Speaker 01

  Oh, man, we don't have time for my follow-up question.

• 34:24Neil deGrasse Tyson?

  Go, next.

• 34:24Speaker 01

  Okay, here.

• 34:25Neil deGrasse Tyson?

  Bring it, bring it.

• 34:26Speaker 01

  No, I gotta ask my.

• 34:26Neil deGrasse Tyson?

  This is the lightning round, go. I've been a lightning round you, go.

• 34:29Speaker 01

  All right, here we go. Uh, Joey, uh, Carasoni. Joey says, if light.

• 34:34Neil deGrasse Tyson?

  Hey, Joey.

• 34:35Speaker 01

  Hey, Joey.

• 34:35Neil deGrasse Tyson?

  Joey.

• 34:36Speaker 01

  Joey. 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.

• 34:50Neil 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. Next.

• 35:12Speaker 01

  Whoa. Dude, that's awesome. Okay.

• 35:15Neil deGrasse Tyson?

  In lightning round, there's no time to comment on whether it's awesome.

• 35:19Speaker 01

  There is no comments in lightning round? Okay, here we go. If you were living in an era without time, keeping as we know it, how would you map out time?

• 35:28Neil deGrasse Tyson?

  I would map out time by asking what happens before what? So your baby before you're an adolescent, you know, you, you can sequence events, even if you cannot measure the interval between those events. And that way you get some sense of the ordering of life.

• 35:44Speaker 01

  So whatever is measurable, that's what you use to measure?

• 35:46Neil deGrasse Tyson?

  No. You don't even measure. You say this happened before that.

• 35:49Speaker 01

  Well, that's what I mean, sequence, whatever is, whatever is a sequence, that's what you use.

• 35:52Neil deGrasse Tyson?

  Right, right. You just sequence it. And so, yeah, so that's what you do.

• 35:55Speaker 01

  All right, let's move on. Here we go. Uh, Danish, uh, Memmon, uh, says, is the universe necessary for time to exist? For example, was time present within whatever came before the universe?

• 36:09Neil deGrasse Tyson?

  Time as we have defined it exists only within this universe. If we go outside of our universe, we'll have to think up something else 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.

• 36:21Speaker 01

  Right.

• 36:22Neil 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. Next.

• 36:33Speaker 01

  Jeez, that was good. Man, you're just making this stuff up.

• 36:37Neil deGrasse Tyson?

  No, we're running down quick. I got one last one.

• 36:40Speaker 01

  All right, here we go, here we go.

• 36:41Neil deGrasse Tyson?

  Knock it out.

• 36:41Speaker 01

  Is there a place in the universe where you could still see the Big Bang happening? In other words, can you still see the Big Bang?

• 36:46Neil deGrasse Tyson?

  Yes, we see it now. You look far enough away, the light from the Big Bang from a distance 13.7 billion light years away is only now just reaching us. Everybody looking in every direction. Look, if you look far enough away, you see the birth of the universe, and the remnants of that is the cosmic microwave background itself. The universe is a time machine.

• 37:10Speaker 01

  Look at that.

• 37:10Neil deGrasse Tyson?

  Writ large to the light that reaches our telescopes.

• 37:14Speaker 01

  Awesome.

• 37:15Neil deGrasse Tyson?

  Did I do okay?

• 37:16Speaker 01

  Yo, man, you killed it.

• 37:16Neil deGrasse Tyson?

  All right.

• 37:17Speaker 01

  You nailed it.

• 37:17Neil deGrasse Tyson?

  We are StarTalk Radio, brought to you by Bob Grant from the National Science Foundation. I'm Neil deGrasse Tyson, bidding you once and forever to keep looking up. Chuck, thanks for being here.

• 37:29Speaker 01

  You got it.