Things You Thought You Knew – Head in the Clouds

Why are there different types of clouds? Neil deGrasse Tyson and comedian Chuck Nice break down things you thought you knew about twilight, how clouds are made, and why Earth’s coastlines change.

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

• 0:00Neil deGrasse Tyson?

  Hey Startalkians. I've got another Things You Thought You Knew coming your way. This time, we're looking at twilight, clouds, and coastlines. But you gotta check it out to see how they connect and why. See you then.

• 0:18Neil deGrasse Tyson?

  Welcome to Startalk. Your place in the universe where science and pop culture collide. Startalk begins right now.

• 0:32Neil deGrasse Tyson?

  Chuck.

• 0:33Chuck Nice?

  Yeah?

• 0:33Neil deGrasse Tyson?

  I'm gonna tell you about the three twilights.

• 0:35Chuck Nice?

  Uh, no, no, no, no. I'm sorry, I gotta correct you on this one. There are four twilights. You got twilight, then you got new moon, then you got eclipse, and then you got breaking dawn.

• 0:46Neil deGrasse Tyson?

  I'm afraid...

• 0:47Chuck Nice?

  That man can bite me any day, okay?

• 0:50Neil deGrasse Tyson?

  I'm afraid the answer is incorrect.

• 0:51Chuck Nice?

  Okay, what?

• 0:52Neil deGrasse Tyson?

  Astronomically speaking.

• 0:53Chuck Nice?

  Oh.

• 0:54Neil deGrasse Tyson?

  This is a science show.

• 0:55Chuck Nice?

  Oh, okay.

• 0:57Neil deGrasse Tyson?

  Astronomical twilight...

• 0:58Chuck Nice?

  That's crazy.

• 0:59Neil deGrasse Tyson?

  Is a thing. That is an actual thing. So Chuck, I don't know if you know this, but there's three different kinds of twilight.

• 1:07Chuck Nice?

  Clearly, I did not.

• 1:08Neil deGrasse Tyson?

  Okay.

• 1:08Chuck Nice?

  Oh, wait, yes, I do know. So there's the one in the evening, and then there's the one in the morning, and then there's the one where Edward takes my heart?

• 1:20Neil deGrasse Tyson?

  That's not correct.

• 1:21Chuck Nice?

  Okay, I'm sure, I'm pretty sure it was. But go ahead, what are the three?

• 1:25Neil deGrasse Tyson?

  So twilight, in any given place on Earth, we rotate in such a way so that the sun dips below your horizon. Unlike some movies and some court cases and some people who think that the instant the sun sets, it's dark.

• 1:45Chuck Nice?

  Right.

• 1:45Neil deGrasse Tyson?

  Okay? Nothing could be more false than that. They made this mistake in Back to the Future when Marty goes back to 1955 and he's driving out from the barn, because he visited the farmer's barn in his DeLorean. And it is dark at the beginning of the driveway, and at the end of the driveway, you see sunrise, and it's light. No, no.

• 2:15Chuck Nice?

  Mm hmm.

• 2:15Neil deGrasse Tyson?

  That's not how that works.

• 2:16Chuck Nice?

  Alright.

• 2:17Neil deGrasse Tyson?

  Okay, in John Wick four.

• 2:19Chuck Nice?

  Yes.

• 2:19Neil deGrasse Tyson?

  There's this scene that happens early morning hours.

• 2:22Chuck Nice?

  Yeah.

• 2:23Neil deGrasse Tyson?

  And he ascends this staircase up to this plateau. And it's dark and then the sun rises and then it's light.

• 2:31Chuck Nice?

  Hmm.

• 2:32Neil deGrasse Tyson?

  Okay, no, no, these people just have never looked up. Okay, they think the sun alone, direct sunlight is their only source of light. You know what else is lighting things up? The atmosphere.

• 2:44Chuck Nice?

  Okay.

• 2:45Neil deGrasse Tyson?

  So the sun dips below the horizon. Light is still illuminating the atmosphere above your head.

• 2:51Chuck Nice?

  Right.

• 2:52Neil deGrasse Tyson?

  It is still glowing from sunlight. That's called twilight. We have a word for that twilight.

• 2:58Chuck Nice?

  Oh, it's beautiful.

• 2:59Neil deGrasse Tyson?

  It's be- it's beautiful.

• 3:00Chuck Nice?

  That's gorgeous.

• 3:01Neil deGrasse Tyson?

  It is beautiful.

• 3:02Chuck Nice?

  Yeah.

• 3:02Neil deGrasse Tyson?

  By the way, if we had no atmosphere and the sun went below the horizon, dark.

• 3:07Chuck Nice?

  Dark. Hmm.

• 3:09Neil deGrasse Tyson?

  Dark.

• 3:10Chuck Nice?

  Oh, you know, they have that on the moon.

• 3:12Neil deGrasse Tyson?

  Yes.

• 3:12Chuck Nice?

  Yes.

• 3:13Neil deGrasse Tyson?

  That's why all of our astronauts landed in the daytime.

• 3:16Chuck Nice?

  That's.

• 3:19Neil deGrasse Tyson?

  Okay, that's a good, because otherwise the lights go out.

• 3:22Chuck Nice?

  Yeah, it's it, yeah.

• 3:23Neil deGrasse Tyson?

  Okay, so you can ask, the deeper below your horizon the sun goes, the higher and higher up the sunlight is hitting. So the lower atmosphere is more and more in darkness, okay? If it's really far around the other side, there's no light illuminating any part of the air above you.

• 3:43Chuck Nice?

  We call that nighttime, right?

• 3:45Neil deGrasse Tyson?

  Night. Very good.

• 3:49Chuck Nice?

  Just want to let you know I'm with you.

• 3:53Neil deGrasse Tyson?

  Alright, there are three kinds of twilight. There is civil twilight.

• 3:58Chuck Nice?

  Alright, hello, I'm Twilight. So terribly nice to meet you. Quite frankly, I don't want to offend you in any way possible.

• 4:07Neil deGrasse Tyson?

  I saw a comedy skit with civil engineers.

• 4:10Chuck Nice?

  Right.

• 4:10Neil deGrasse Tyson?

  And they're sitting there offering each other.

• 4:12Chuck Nice?

  After you.

• 4:13Neil deGrasse Tyson?

  Would you like some?

• 4:13Chuck Nice?

  Would you care for, would you care for another pinafore? Oh, my good man, please, I wouldn't, wouldn't dare. Civil engineers.

• 4:23Neil deGrasse Tyson?

  If only civil wars could be that polite.

• 4:25Chuck Nice?

  Oh, wouldn't that be something? You know, I would kill you, but that would be rather unpleasant, wouldn't it?

• 4:31Neil deGrasse Tyson?

  A civil war.

• 4:32Chuck Nice?

  What's a civil war?

• 4:34Neil deGrasse Tyson?

  Let's just play checker.

• 4:35Chuck Nice?

  Exactly.

• 4:36Neil deGrasse Tyson?

  A civil twilight. Is until the sun is six degrees below the horizon. Six degrees below the, so, okay, it's a Kevin Bacon twilight, gotcha. Six degrees, okay, okay. There's still some light in the upper atmosphere, still lighting it. But for practical purposes, for ordinary people, nighttime begins when it's six degrees below. There you go. Okay. Civil twilight. Civil twilight. So people don't have much need for the sky like other people do. So civil twilight, six degrees. Let's keep going. There's another twilight called nautical twilight. Oh, okay.

• 5:18Neil deGrasse Tyson?

  It's gotta be darker than civil twilight for them to use their sextant and they're navigate by the stars. Makes sense. It makes sense. So the sun's gotta be 12 degrees below the horizon. Look at that. Yeah. And at that point, you start seeing many more stars for you to navigate by. Okay. Where six degrees, not so much. Right, because there's still light in the atmosphere. Light in the atmosphere above you. The sky's still glowing blue. Right. The blue sky is light from the sun. Right. Scattered back to you. Right. On the moon, there is no scattered light. So the sky, daytime sky is as dark as night. Black. Black. So nautical. Nautical. Civil nautical. They get some more stars to play with, okay? But the astronomers.

• 6:04Neil deGrasse Tyson?

  Hmm. We go deeper than what the eye can see. Right. We bring out telescopes. I don't want twilight messing with my telescopic views of the night sky. So we go an extra six degrees lower than nautical twilight. Wow. Eighteen degrees below the horizon. Okay. Only then is the end of astronomical twilight. Wow. Yeah. And what, what, what, what time would that be about? Well, no, so it depends. If you're near the equator,

• 6:38Chuck Nice?

  Mm-hmm.

• 6:39Neil deGrasse Tyson?

  the angle that the sun sets to the horizon is almost vertical.

• 6:43Chuck Nice?

  Right.

• 6:45Neil deGrasse Tyson?

  So if you're going vertically down, you're booking into the darkness, okay? Twilight lasts like fifteen minutes. I mean, have you ever been in the Caribbean?

• 6:51Chuck Nice?

  Yeah.

• 6:52Neil deGrasse Tyson?

  There is no culture of twilight in the Caribbean.

• 6:54Chuck Nice?

  That's true.

• 6:55Neil deGrasse Tyson?

  Okay?

• 6:56Chuck Nice?

  Yeah.

• 6:56Neil deGrasse Tyson?

  It's light and then it's dark, not instantaneously at sunset, but the sun goes down fast. At most an hour, an hour. An hour later is fifteen degrees below the horizon. You're done.

• 7:07Chuck Nice?

  You're done.

• 7:08Neil deGrasse Tyson?

  You're done.

• 7:08Chuck Nice?

  Right.

• 7:09Neil deGrasse Tyson?

  But the farther away from the equator you go, towards the poles, the sun's angle to the horizon gets shallower and shallower. So, so here comes the sunset. And how long does it take to get deep below it? Well, it's ambling its way along a hypotenuse, okay?

• 7:30Chuck Nice?

  Okay.

• 7:30Neil deGrasse Tyson?

  Along a slopy angle, so twilight could last hours and hours.

• 7:34Chuck Nice?

  Right.

• 7:35Neil deGrasse Tyson?

  Do you know all of England sits north of the northernmost part of Maine?

• 7:41Chuck Nice?

  Wow, I didn't know that. Of course not.

• 7:43Neil deGrasse Tyson?

  Okay, so.

• 7:45Chuck Nice?

  Why would I ever know that?

• 7:46Neil deGrasse Tyson?

  So, England has very long twilights.

• 7:48Chuck Nice?

  Very long twilight.

• 7:49Neil deGrasse Tyson?

  Very long twilights.

• 7:50Chuck Nice?

  Oh, is that why, uh, where is it, where they have like?

• 7:53Neil deGrasse Tyson?

  Oh, so if you keep going even farther north.

• 7:56Chuck Nice?

  Yeah.

• 7:56Neil deGrasse Tyson?

  Okay. There is no night, it's all twilight.

• 7:59Chuck Nice?

  It's just twilight.

• 8:00Neil deGrasse Tyson?

  The sun never gets below your designated level. If it's astronomical twilight, it stays above eighteen degrees.

• 8:05Chuck Nice?

  Right.

• 8:05Neil deGrasse Tyson?

  Or above twelve for nautical, above six. So then, my wife is from Alaska, they.

• 8:10Chuck Nice?

  They just.

• 8:10Neil deGrasse Tyson?

  Fairbanks, the midnight softball game on the solstice, the summer solstice.

• 8:14Chuck Nice?

  Right.

• 8:14Neil deGrasse Tyson?

  Yeah, it's just twilight the whole time.

• 8:16Chuck Nice?

  Twilight the whole time.

• 8:16Neil deGrasse Tyson?

  Yeah, so these are your twilights. I don't know how many people know about them, so recite them to me, what are they?

• 8:21Chuck Nice?

  So you got your civil, of course, and then your nautical, and then your astronomical, or as we're gonna call that one, the neolight. Neolight.

• 8:35Neil deGrasse Tyson?

  No, it's gotta be, no.

• 8:37Chuck Nice?

  You don't like that?

• 8:38Neil deGrasse Tyson?

  No.

• 8:38Chuck Nice?

  Cause it's got your name in it?

• 8:39Neil deGrasse Tyson?

  No.

• 8:39Chuck Nice?

  You don't want, no.

• 8:40Neil deGrasse Tyson?

  No. So there you have it, three twilights.

• 8:42Chuck Nice?

  Nice.

• 8:43Neil deGrasse Tyson?

  And when we go observing on mountain tops, the, we are given the time of astronomical twilight. So we can plan our observing schedule around that.

• 8:52Chuck Nice?

  Very cool.

• 9:06Speaker 02

  I'm Kais from Bangladesh and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 9:23Neil deGrasse Tyson?

  Chuck, these don't stop.

• 9:25Chuck Nice?

  Okay, that's fine with me.

• 9:26Neil deGrasse Tyson?

  Another explainer.

• 9:27Chuck Nice?

  Excellent.

• 9:28Neil deGrasse Tyson?

  Okay, this one on clouds. Have we done a clouds one before? Cause you have better memory than I do.

• 9:33Chuck Nice?

  We didn't, we have not done clouds.

• 9:35Neil deGrasse Tyson?

  We have not done clouds.

• 9:36Chuck Nice?

  Yeah, and you know, I wouldn't think there was a lot to talk about with clouds. And maybe that's why we haven't done it.

• 9:42Neil deGrasse Tyson?

  But have you looked at clouds from both sides now?

• 9:46Chuck Nice?

  Okay, you mean top and bottom?

• 9:56Neil deGrasse Tyson?

  Joni Mitchell, forgive us.

• 9:59Neil deGrasse Tyson?

  So, you ever wondered why clouds are just up there?

• 10:03Chuck Nice?

  I mean, I know, I mean, I haven't wondered. I mean, once I found out that clouds were basically water droplets.

• 10:12Neil deGrasse Tyson?

  Yeah.

• 10:13Chuck Nice?

  Just basically vapor.

• 10:14Neil deGrasse Tyson?

  Yeah.

• 10:15Chuck Nice?

  They became extremely uninteresting to me at that point.

• 10:18Neil deGrasse Tyson?

  Okay, let me re, let me get you more, get your interest back going for me.

• 10:21Chuck Nice?

  Okay.

• 10:22Neil deGrasse Tyson?

  Okay, all right. Allow me to remind you that the sun does not heat the air.

• 10:28Chuck Nice?

  That I understand.

• 10:29Neil deGrasse Tyson?

  The sun heats the ground.

• 10:31Chuck Nice?

  And the ground radiates.

• 10:32Neil deGrasse Tyson?

  And that heats the air. And it radiates in what band of light?

• 10:36Chuck Nice?

  Uh, infrared.

• 10:37Neil deGrasse Tyson?

  Infrared.

• 10:37Chuck Nice?

  Right.

• 10:38Neil deGrasse Tyson?

  And CO2 in the atmosphere actually traps infrared.

• 10:41Chuck Nice?

  Right. Oh, God, do I know.

• 10:43Neil deGrasse Tyson?

  Okay, so.

• 10:43Chuck Nice?

  What a shame.

• 10:44Neil deGrasse Tyson?

  So it's otherwise transparent to sunlight, the ordinary visible light. But once the ground absorbs it, it reradiates back infrared. There you get the trapping, what they call the greenhouse effect.

• 10:57Chuck Nice?

  Okay, did you hear that, people? That's how simple it is. Did you see how simple that is? Okay, comes in as visible light and passes through everything with no problem. Heats the ground, ground sends it back.

• 11:11Neil deGrasse Tyson?

  Yep.

• 11:12Chuck Nice?

  As infrared gets trapped, heats the earth, re, climate change.

• 11:18Neil deGrasse Tyson?

  So how do you know the atmosphere is transparent to visible light?

• 11:23Chuck Nice?

  How do we know?

• 11:23Neil deGrasse Tyson?

  Yes.

• 11:24Chuck Nice?

  I don't know.

• 11:25Neil deGrasse Tyson?

  Cause you can see the sun.

• 11:28Neil deGrasse Tyson?

  No. That makes sense. If it were not transparent. Transparent. You wouldn't see the sun. See the sun. Wouldn't be able to see the sun. And there you have. Okay. Right. Uh, let me be more blunt. Windows are transparent to visible light. Right. How do you know this? Cause I can see through. You can see through them. Right. Walls are not transparent to visible light. Cause I'm not Superman. That's a. Okay, so Superman, back then, X-rays were like relatively new. They'd. Right. X-rays were discovered in like, the first Nobel Prize in Physics was given for the discovery of X-rays. Wow. Yeah, so it was the late eighteen nineties, nineteen hundred was the first time that was awarded. So, first Superman comic was like maybe nineteen thirties, so X-rays are still kinda cool. Yeah, they're like, woo.

• 12:12Neil deGrasse Tyson?

  Alright, but, radio waves go through walls also. Right. So he could have had radio wave vision. And then he'd have to tune in his eyes.

• 12:22Neil deGrasse Tyson?

  Okay. So, but back then, X-ray was just metaphor for seeing. Seeing through things, right. That's all I want. Alright, so, infrared does not pass through windows. Not easily. Not easily? No. Okay. Do this experiment. If you're in a fireplace, right, and you're, have some distance from the sun. Get someone to walk in front of you with a plate glass window. In that instant, you don't feel any of the radiant heat from the, from the fire. The heat is, uh, right, blocked. It blocked. Right. Okay. Okay. That's cool. It blocks it. So if you had infrared vision, a window is just the same thing as a wall to you. Right. Just think about that. Okay. Alright, so some, some things are not just inherently transparent, they're only transparent to certain wavelengths of light. Alright, so now.

• 13:07Neil deGrasse Tyson?

  And none of that has anything to do with clouds. Okay, but that was still interesting. Framing information here. Exactly. Alright, sunlight heats the ground, the ground heats the air. The farther away you are from the ground, the less heat you're getting. Wrong, that makes sense. Okay, have you ever tracked the temperature in an airplane? Sometimes they do it on the. Yeah. On track your plane thing. Right. Okay, what's the temperature up there? Cold. Cold, thank you. That's the temperature. Is it exactly? Very, very cold. It's exact, you measured it. Exactly. It's cold. Cold. Okay, it could be as low as forty below. Right, yeah. Forty below zero. And Peggy Lee's Fever. Right. Alright, and that's, we know, we all know that song. You're giving me fever.

• 13:44Chuck Nice?

  In the morning. Right, right, right.

• 13:50Neil deGrasse Tyson?

  So all the occasions where one gets fever.

• 13:52Chuck Nice?

  Right.

• 13:52Neil deGrasse Tyson?

  Right. One of the stand- stances toward the end is, now you've listened to my story. Here's the point that I have made. Chicks are born to give you fever. Be it Fahrenheit or centigrade.

• 14:05Chuck Nice?

  Oh.

• 14:06Neil deGrasse Tyson?

  Getting both temperature scales.

• 14:08Chuck Nice?

  Yes.

• 14:08Neil deGrasse Tyson?

  In the song.

• 14:09Chuck Nice?

  In the most sexist way possible. And from a woman. That's how bad it was back then. That's how bad it was back then. Even the women were sexist. Chicks were born to give you fever.

• 14:24Neil deGrasse Tyson?

  No, here's why I even went there.

• 14:26Chuck Nice?

  Go ahead.

• 14:26Neil deGrasse Tyson?

  Well, first of all, I- I'm giving him a hall pass because Fahrenheit is a human being's name.

• 14:33Chuck Nice?

  Right.

• 14:33Neil deGrasse Tyson?

  Who actually invented the- the thermometer.

• 14:35Chuck Nice?

  Right.

• 14:36Neil deGrasse Tyson?

  The- the mercury thermometer.

• 14:38Chuck Nice?

  Also American.

• 14:41Chuck Nice?

  Thermometer.

• 14:42Neil deGrasse Tyson?

  Centigrade, that's not somebody's name.

• 14:45Chuck Nice?

  Right. That's a scale.

• 14:46Neil deGrasse Tyson?

  It's a- it's- it's- yeah. So what they should have said was Fahrenheit or Celsius.

• 14:49Chuck Nice?

  Right. Well, then it wouldn't rhyme.

• 14:50Neil deGrasse Tyson?

  Then it wouldn't rhyme. So that's why I gotta give him a hall pass on that one.

• 14:53Chuck Nice?

  Right, right.

• 14:53Neil deGrasse Tyson?

  Okay. Ask me why I even went there.

• 14:56Chuck Nice?

  Why did you even go there?

• 14:57Neil deGrasse Tyson?

  Because the Fahrenheit and Celsius scale cross at forty degrees below zero.

• 15:04Chuck Nice?

  Oh, interesting.

• 15:06Neil deGrasse Tyson?

  Forty below zero, you don't even have to say.

• 15:08Chuck Nice?

  You don't have to say.

• 15:09Neil deGrasse Tyson?

  It's the same on both scales.

• 15:10Chuck Nice?

  It's just the same thing.

• 15:11Neil deGrasse Tyson?

  The only temperature for which that is true.

• 15:13Chuck Nice?

  Forty below?

• 15:14Neil deGrasse Tyson?

  Yes, it is.

• 15:15Chuck Nice?

  Yo, that's kinda- that, right? I'm ready to stop this play right now. That is great information. The only temperature that exists both Fahrenheit and centigrade at the same point is forty.

• 15:27Neil deGrasse Tyson?

  They cross at that temperature.

• 15:28Chuck Nice?

  Forty below zero.

• 15:29Neil deGrasse Tyson?

  And it- and it's within a degree of the temperature that mercury freezes.

• 15:32Chuck Nice?

  Right.

• 15:33Neil deGrasse Tyson?

  Which is especially relevant to mercury thermometers. As you get higher, the temperature drops.

• 15:37Chuck Nice?

  Right.

• 15:37Neil deGrasse Tyson?

  Because you're getting farther away from Earth's surface with- where the sun is heating. This reverses in the thermosphere where ultraviolet is absorbed by the ozone layer. Wasn't it have to do with clouds? Because clouds are formed in warm, moist, unstable air.

• 15:57Chuck Nice?

  Okay.

• 15:58Neil deGrasse Tyson?

  If you're unstable, it means you're not gonna stay where you are. You're gonna rise. I have a pocket of air at sea level or just near the ground. Pocket- oh, by the way, the official temperature that gets measured. Is at a predetermined height above the ground. Okay, right. Just so it can be standardized. Yeah. Otherwise. You'd have different temperatures. Everywhere. You're up in a building, you get a different temperature there. Right. Then if you're sleeping on a, on a, on a, on a, a, a, a picnic, a picnic blanket. Right. Right, so they have to standardize that. Got you. For this reason, alright, so now it's a pocket of air. And it has hu- some humidity level in it. Okay. Okay, give me a percent, let's say it's fifty percent humid. Okay. Not bad, New York City, that's very typical. Yeah, no. Deserts, it's down in like, single digits.

• 16:43Neil deGrasse Tyson?

  Right. Uh, rainforests is always up above eighty, ninety, eighty, ninety, sorry. New York is fifty percent. That humidity that is reported is actually a relative humidity. Okay. Okay, what that means is, that is, it is fifty percent relative to how much it could carry at that temperature. As the blob of air gets heated and rises. Right. The temperature drops. Colder air can hold less humidity than warmer air. Mm-hmm. So the relative humidity goes up. Got you. It starts at fifty in this example, it goes to sixty, then to seventy, then to eighty.

• 17:26Neil deGrasse Tyson?

  So let's, let's take eighty, at eighty percent, you didn't add more water to it. No. The capacity of the air to hold it dropped. Right. Okay, so nevermind, so there it is, it is ascending, eighty, ninety. Ba-da-bing, you reach a hundred percent. Right. A hundred percent humidity. The, the humidity condenses out as water droplets. Right. Water vapor, basically, okay? And boom, you have a cloud. That's why the cloud is up there and not down here. And now, now I know how clouds are born. That's how clouds are born. And, and all this time, I thought you had a mommy cloud and a daddy cloud, and they loved each other very much. A stork cloud.

• 18:09Neil deGrasse Tyson?

  That's kind of dope, though. So, and it's because of this temperature gradient from high temperature to low temperature from the ground on up. Right. Okay, there are two ways you won't get clouds.

• 18:21Chuck Nice?

  Okay.

• 18:22Neil deGrasse Tyson?

  At no matter your height.

• 18:23Chuck Nice?

  Mm hmm.

• 18:23Neil deGrasse Tyson?

  There's not enough humidity here.

• 18:26Chuck Nice?

  Right.

• 18:26Neil deGrasse Tyson?

  Where even if it rises, it can go ten, twenty, thirty, fifty, seventy, and it never hits a hundred before it gets way up in the afternoon. No cloud.

• 18:33Chuck Nice?

  No cloud. The other way is, uh, the blob of air has autonomy and a right to choose. It doesn't have to have a baby cloud if it doesn't want to.

• 18:45Neil deGrasse Tyson?

  Is that where you were going with that?

• 18:46Chuck Nice?

  Okay.

• 18:47Neil deGrasse Tyson?

  We were still on the baby making clouds.

• 18:49Chuck Nice?

  I was, well, sorry, sorry.

• 18:50Neil deGrasse Tyson?

  Okay, I had moved on from that, but okay.

• 18:52Chuck Nice?

  I couldn't.

• 18:52Neil deGrasse Tyson?

  You couldn't. You were still, okay, the juvenile brain stayed with it.

• 18:56Chuck Nice?

  My childlike brain.

• 18:57Neil deGrasse Tyson?

  All right.

• 18:57Chuck Nice?

  But that makes sense because it's really about the water that it's holding. So.

• 19:03Neil deGrasse Tyson?

  Yes, exactly.

• 19:04Chuck Nice?

  And the relative humidity as it has.

• 19:05Neil deGrasse Tyson?

  Capacity to hold.

• 19:06Chuck Nice?

  Capacity to hold.

• 19:07Neil deGrasse Tyson?

  To hold humidity.

• 19:09Chuck Nice?

  Right.

• 19:09Neil deGrasse Tyson?

  Okay, so now, so one way is it starts out so low, even though it gets high up, it never hits a hundred percent.

• 19:14Chuck Nice?

  Right.

• 19:15Neil deGrasse Tyson?

  No cloud gets formed.

• 19:16Chuck Nice?

  Right.

• 19:16Neil deGrasse Tyson?

  Another way is if you have descending air.

• 19:20Chuck Nice?

  Ooh.

• 19:21Neil deGrasse Tyson?

  That can happen. You could, so you can have, for example, a cold air moving through the mountains. And cold air is, is, is, uh, and then it comes into a valley. And it descends, it comes down over the mountain tops. Okay? If you have descending air, what's happening to the air? The air temperature.

• 19:42Chuck Nice?

  Well, it's getting warmer.

• 19:43Neil deGrasse Tyson?

  It's getting warmer.

• 19:43Chuck Nice?

  So, and then condensation again.

• 19:46Neil deGrasse Tyson?

  It can now keep holding more and more and more. You're not making clouds.

• 19:49Chuck Nice?

  Right.

• 19:49Neil deGrasse Tyson?

  So descending air does not make clouds because it keeps getting warmer.

• 19:52Chuck Nice?

  Right.

• 19:53Neil deGrasse Tyson?

  This ascending air with not enough moisture will not make a cloud because it'll never get to a hundred percent.

• 19:58Chuck Nice?

  Right. Okay. All right. So far, this is cool.

• 20:01Neil deGrasse Tyson?

  Okay, you ready? Okay, so now suppose there's no wind. And you got like, let's say seventy percent humidity.

• 20:07Chuck Nice?

  All right.

• 20:08Neil deGrasse Tyson?

  The sun sets, the temperature drops, gets to a hundred percent.

• 20:14Neil deGrasse Tyson?

  What happened? What just happened? We made a cloud. Where did, where we, where did we make the cloud? Where the air is, I mean.

• 20:23Neil deGrasse Tyson?

  Thank you Chuck for that brilliant answer. Right in front of me. Yeah, of course, it would be right here. Right here. Yeah. We have a new word for that kind of cloud. Do we really? Yes. What? Fog.

• 20:35Neil deGrasse Tyson?

  You got me. It's fog. That's fog. And that's the cloud. That's why when it's foggy, it's always a little cold. Yes. You ever notice that? Yeah, yeah, yeah. It's a little cold. A little chilly. And it's a little dank, a little chilly. So the fog is when you get this, you reach, it's called a dew point, to be precise. The dew point, and it's right at the ground level. Nice. And so it's, it's interesting that in our language, you have a different word for a cloud above your head than for the same damn cloud right here, right in front of you. If the cloud formation is vigorous, like the temperature dropped real fast. Right. And it was really humid, and it, and it'll, it comes up there and it's still being unstable and it's rising

• 21:19Neil deGrasse Tyson?

  and it's turning into, into water droplets, you get a cumulus cloud. Okay. Okay? If this is intense and it's unrelenting and it continues to build, that cumulus cloud, which is just white with sunlight moving through it. Right. It becomes less white. Okay. Because the droplets are getting bigger and bigger. Oh, oh. Okay, and it starts getting gray. Nice. We have a gray cumulus cloud, you get cumulonimbus. Okay. That stuff hurts you.

• 21:54Neil deGrasse Tyson?

  So the cumulonimbus, now the water droplets are so, it is so laden with water. Right. It cannot contain the humidity. Right. Even at a hundred percent. And so the humidity nucleates, it finds droplet, dust in the air, things, it says, and other, other bits of, of water vapor collect to it. And it's held there for a while because you have updrafts because that's how you made the cloud in the first place. Right. But then it gets so big, it drops out. So the more vigorous the cloud is, the heavier the raindrops are.

• 22:29Chuck Nice?

  Uh huh.

• 22:30Neil deGrasse Tyson?

  Because it was holding them up.

• 22:32Chuck Nice?

  Right.

• 22:33Neil deGrasse Tyson?

  Okay.

• 22:33Chuck Nice?

  Right, right, right.

• 22:34Neil deGrasse Tyson?

  Very fast moving air is holding up until it can't hold it up anymore. And that big fat ass drop falls out of the sky and you get the big drop thunderstorms.

• 22:44Chuck Nice?

  Nice.

• 22:45Neil deGrasse Tyson?

  Okay. Now, let's say it's even more vigorous than that.

• 22:49Chuck Nice?

  Uh oh.

• 22:50Neil deGrasse Tyson?

  Okay.

• 22:50Chuck Nice?

  We went from cumulus nimbus to cumulus negro. That's when the clouds get black.

• 22:57Neil deGrasse Tyson?

  Yeah, they get black. They get, they get black, okay? So.

• 23:02Neil deGrasse Tyson?

  So, the updrafts are so severe.

• 23:05Chuck Nice?

  Right.

• 23:06Neil deGrasse Tyson?

  Okay, oh, I, I forgot to tell you. Often the rain forms as snow, as, as water crystals. Cause it's high up.

• 23:13Chuck Nice?

  Right, right.

• 23:14Neil deGrasse Tyson?

  Okay.

• 23:14Chuck Nice?

  Right, very cold.

• 23:16Neil deGrasse Tyson?

  And, and, and you can keep those pretty buoyant, but then as it begins to fall, it gets to a warmer air temperature and it just melts into rain.

• 23:23Chuck Nice?

  Right.

• 23:23Neil deGrasse Tyson?

  Okay, so, all right, now, imagine updrafts so strong that not even the raindrops can fall out. And it just stays up there. The thing freezes and gets bigger and bigger. And then one day it says, I can't hold you anymore, I gotta let you go. And now it's too big to melt.

• 23:41Chuck Nice?

  Oh my god.

• 23:42Neil deGrasse Tyson?

  And what do you get?

• 23:43Chuck Nice?

  You got hail.

• 23:44Neil deGrasse Tyson?

  Hail.

• 23:45Chuck Nice?

  That's terrible.

• 23:45Neil deGrasse Tyson?

  You got hail.

• 23:46Chuck Nice?

  Hmm.

• 23:47Neil deGrasse Tyson?

  It's all because of the updrafts.

• 23:48Chuck Nice?

  Right.

• 23:49Neil deGrasse Tyson?

  That's updrafts.

• 23:50Chuck Nice?

  That's an insurance cloud.

• 23:55Neil deGrasse Tyson?

  So the conclusion here is the bigger the hail, that means the bigger the hail.

• 23:59Chuck Nice?

  Pellets.

• 24:00Neil deGrasse Tyson?

  Pellets, spheres, the more severe the storm was.

• 24:04Chuck Nice?

  Right.

• 24:05Neil deGrasse Tyson?

  Because it meant the updrafts were just so significant, it was so catastrophic, turning just moist air into.

• 24:12Chuck Nice?

  Giant balls of ice.

• 24:13Neil deGrasse Tyson?

  Giant balls of ice, that's right. Yeah. Go on. By the way, with these puffy clouds, it's why they're more frequent in the tropics. Because you still have the ground heating, but you start out with such higher humidity air. Right. That when it rises, of course, you're gonna puff up a cloud, like right there. Now, if you puff off a cloud here and not over there, then it could be raining over there and not over here. Right, yeah. Okay? And that's this, this is the conditions, almost all the conditions you need for a rainbow. Okay. Okay? So to have a rainbow, you know, it's very specific. I don't know if you knew this. Uh. Okay? Right.

• 24:54Neil deGrasse Tyson?

  So, it's gotta be raining in front of you. And it has to be late in the, late enough in the day for the sun to be low enough in the sky for the sun to be behind you. That makes sense. Okay? So it can create the. It would be a late afternoon thunderstorm. Right. That's over there. Right. The sun is yonder. And the sun is behind you. Right. Okay? That's why you never see a rainbow in the middle of the day. Cause the sun is directly overhead. Right, and it's not raining under your knees. Right. Right, you would if in a, in a sprinkler. Right. A lawn sprinkler. What if you're in a plane looking down? Yes! If you're in a plane looking down, you, you, you got full view. You can actually see it. Yeah. Awesome. Yeah, you got it. That's great. Yeah.

• 25:36Neil deGrasse Tyson?

  So, so these are the configurations here, and there are other kinds of clouds, like I said. Um, cirrus clouds are, they can be transparent, but they mess with our viewing of the night sky. Little wispy, thin clouds. Right, right. And these are clouds that just hang out up there, and they're just, um, they're very stable cirrus clouds. And then you have weather fronts that come in, where there's a change in temperature. You never heard of a warm front coming in, bringing bad weather. Right. That's, that's not how that works. Always a cold. Because if things get warmer, you're gonna hold more moisture. More moisture. It's when the cold front comes in. Right. The cold front comes in. Messing up everything. And you had warm air that had moisture. Right.

• 26:19Neil deGrasse Tyson?

  And they meet at the boundary, it turns your moisture into rain, into storms, into clouds. Right. And so it's always the cold front you gotta watch out for. It's the drunk uncle at the cookout. The cold front. It's messing things up. Alright, so, uh, just one other interesting thing, I think. Okay. And it, these are especially visible in airplanes. You see these long, I'll call them columns, but they're horizontal. Columns of clouds.

• 26:46Chuck Nice?

  Yeah.

• 26:47Neil deGrasse Tyson?

  One after another.

• 26:48Chuck Nice?

  Yes.

• 26:49Neil deGrasse Tyson?

  These are called cloud streets.

• 26:51Chuck Nice?

  Cloud streets?

• 26:52Neil deGrasse Tyson?

  Streets.

• 26:52Chuck Nice?

  Okay.

• 26:53Neil deGrasse Tyson?

  Cloud streets. Okay, because the clouds that I just described, the air goes up. But wait a minute, if air is going up, what's replacing that air?

• 27:03Chuck Nice?

  Got to be more air.

• 27:04Neil deGrasse Tyson?

  More, more.

• 27:06Neil deGrasse Tyson?

  Thank you, Chuck.

• 27:09Neil deGrasse Tyson?

  Brilliant answer. Okay. So for every bit of air that goes up, there's air that drops down and comes in to fill the gap. So these are, these are convective cells. It's, okay, that's what's happening here. But in a cloud street, the convective cell is cylindrical.

• 27:26Chuck Nice?

  Interesting.

• 27:26Neil deGrasse Tyson?

  Okay. So imagine a horizontal cylinder that's rotating.

• 27:32Chuck Nice?

  Oh, nice.

• 27:34Neil deGrasse Tyson?

  On the side that's rotating up, you get cloud formation. And on the side that's rotating down, no clouds form.

• 27:41Chuck Nice?

  Right.

• 27:42Neil deGrasse Tyson?

  Because it's going, it's downward air. We, we've been through that.

• 27:44Chuck Nice?

  Right.

• 27:44Neil deGrasse Tyson?

  Okay. And so, but wait a minute, how about the other cylinder? It has to be turning the opposite way. Otherwise, they would cancel.

• 27:52Chuck Nice?

  Right.

• 27:53Neil deGrasse Tyson?

  You can't have up air and down air simultaneously in the same place. So these cloud streets have cylinders rolling with sides that match each other, both going down or both going up.

• 28:06Chuck Nice?

  Oh.

• 28:06Neil deGrasse Tyson?

  So the next time you're in an airplane, look for this. It's, it's beautiful. It's beautiful. And it can go on for miles and miles.

• 28:11Chuck Nice?

  Nice.

• 28:12Neil deGrasse Tyson?

  And these, so again, depending on how the terrain is heated, where the moisture is, is there a lake? Is there an ocean? Is there a, um, uh, is there asphalt, which gets, heats higher, hotter than, than other. So all of this makes with a beautiful diversity of clouds we see and love in the sky.

• 28:31Chuck Nice?

  That's very cool. Uh, and, and, and to think that all we ever do is look at them and see bunny rabbits and.

• 28:40Neil deGrasse Tyson?

  And George Washington.

• 28:41Chuck Nice?

  And right, always George Washington.

• 28:43Neil deGrasse Tyson?

  Well, he's got the, he's got the.

• 28:44Chuck Nice?

  What a president.

• 28:45Neil deGrasse Tyson?

  He's got the, the, you know.

• 28:46Chuck Nice?

  Yeah.

• 28:46Neil deGrasse Tyson?

  He's got the do for it.

• 28:48Chuck Nice?

  That's true.

• 28:48Neil deGrasse Tyson?

  Yeah.

• 29:12Neil deGrasse Tyson?

  So Chuck. Yes. Asking me about coastlines. What's going on with coastlines, Neil? I thought you'd never ask. Yeah. Well, we're in my office here, so nothing is ever farther than an arm's reach. Right. For whatever I gotta use. Okay. So I'm just reaching right here. And... Look at that. I got the whole world. There you go. In my hands. Did anyone sing that anymore? I bet they don't. No. No, cuz that was so kumbaya. Yeah. United Nations. It was like, bring it all together. Bring it all together. Hippie love. Hippie love. Not anymore. Days are gone. All right. Anyhow, so here's the Earth. When we think of Earth, we say to ourselves, there are bodies of water. Right. Oceans are the largest.

• 29:58Neil deGrasse Tyson?

  And there's land. Mm-hmm. And we see this and we think about it as though it's a fundamental feature of our planet. That's Africa. Right. Cuz it has that shape. Right. Here's Asia with this coastline. And Japan is an island. We, we, we have this understanding of the world brought to you by settlers and explorers and politicians. Okay. With a few wars thrown in here and there. You always gotta have a war, a good war to bring about changes in geography. It's also color-coded. Right. Which I came to realize, in my cynical adulthood, are ways so that you can learn early on

• 30:43Neil deGrasse Tyson?

  who your friends are and who your enemies are. Ooh. Because none of this is visible from space. No, it isn't. No, it's just land. And it's just land. Okay. Right. All right. So, when you take a look at a coastline, there's the urge to think there's something fundamental about it. Mm-hmm. But there isn't. Oh, really? That's just the coastline today.

• 31:05Neil deGrasse Tyson?

  That makes sense. Okay. Right. Have you seen maps where you can look through the ocean, through the, the, the water? Like so in, in North America, for example, here we go. Have you ever seen maps where you can see that the continent extends a little further out underwater? Have you ever noticed that? Ah. You know what they call it? No. The continental shelf. Right, yeah, that, that, yeah, I've, I've seen that. Well, you've seen that? Yes. And so it kind of follows our contour? Right. But it's way, way out there. Exactly. And in fact, a lot of trash dumping activity in the old days, now you, you, you process the trash. Right. The old days, they would put on a barge and go beyond the continental shelf. Dump. Dump it there so it goes way down to the bottom. Right.

• 31:48Neil deGrasse Tyson?

  Rather than possibly ever washing back up. Right. Okay, and I remember looking at it as a kid and I said, why does the shape of our continent continue underwater? I didn't understand that. Ooh. Cause it's intriguing to me that that, okay. Do you know what that other edge is underwater? That's the coastline of North America when the ocean had less water in it. Right. When the oceans were drained. Yeah, get used to that, people. Wait, I'm getting, get used to that. Wait, wait, hold on. When the oceans were drained, all these coastlines looked different. Right. They were bigger. They were bigger. They were bigger. Yeah.

• 32:30Neil deGrasse Tyson?

  And so, so, well, when was the, were the oceans drained? During the Ice Age. Right. You know how Ice Ages work? You still have your oceans. Mm-hmm. And you still have evaporation for, cause where does water come from that falls out of the sky? It used to be in the ocean. Ocean, didn't come from land. No, of course not. Okay, came from oceans and other bodies of water. Right. All right, so the water evaporates up, but Earth is really, really, really cold. So it goes into the cloud and then the cloud goes over land. And it doesn't rain, it snows.

• 33:01Chuck Nice?

  And deposits that water.

• 33:03Neil deGrasse Tyson?

  As snowflakes. Okay, so the snow is there. Does the snow ever make it back to the ocean? No.

• 33:11Chuck Nice?

  There we go.

• 33:12Neil deGrasse Tyson?

  It stays there.

• 33:13Chuck Nice?

  Stays there.

• 33:13Neil deGrasse Tyson?

  And then another snowfall comes.

• 33:14Chuck Nice?

  Alright, and layers on top.

• 33:16Neil deGrasse Tyson?

  And there's their feet and the yards, and in some cases, miles.

• 33:19Chuck Nice?

  Right. By the way, this is a great opportunity to take the time and explain to people. That's how we know that climate change is real and that the amount of CO2 in the atmosphere is greater today than it was back then. For all you people who say, oh, it's just cyclical. It's not a big deal. That's how we know from what Neil just described, because in each one of those layers, we can count the carbon dioxide.

• 33:44Neil deGrasse Tyson?

  A public service message was brought to you by.

• 33:46Chuck Nice?

  Exactly. So stop it. It's real. Okay, anyway, go ahead.

• 33:50Neil deGrasse Tyson?

  What happens is, the, once the oceans evaporate out and it snows.

• 33:55Chuck Nice?

  Right.

• 33:55Neil deGrasse Tyson?

  On land. By the way, it'll also snow in the ocean and then, okay, it'll just.

• 33:59Chuck Nice?

  It just turns back in the water.

• 34:01Neil deGrasse Tyson?

  Water. Alright, so that's just fine.

• 34:02Chuck Nice?

  Right.

• 34:03Neil deGrasse Tyson?

  But for every snowflake that lands, that goes to land and never melts.

• 34:08Chuck Nice?

  Right.

• 34:08Neil deGrasse Tyson?

  You have systematically drained water from the oceans.

• 34:12Chuck Nice?

  Right.

• 34:12Neil deGrasse Tyson?

  And if this goes on for thousands of years, you then build these layers of snow to make a new form of ice, which is glacial ice. It's not snow and it's not ice in your freezer. It's a different form of matter.

• 34:25Chuck Nice?

  Ooh.

• 34:26Neil deGrasse Tyson?

  For the water molecule.

• 34:27Chuck Nice?

  Exactly.

• 34:27Neil deGrasse Tyson?

  Glacial ice. It's basically compactified snow. Alright, it just stays there. It stays there, frozen. Alright, so you're draining the ocean and as you drain the ocean, oh my gosh, what happened? Oh, back here, the, where Alaska and Asia meet with the Bering Strait.

• 34:47Chuck Nice?

  Hmm.

• 34:48Neil deGrasse Tyson?

  Our ancestors.

• 34:49Chuck Nice?

  Walked over.

• 34:50Neil deGrasse Tyson?

  Oh, they didn't take a boat.

• 34:52Chuck Nice?

  What?

• 34:53Neil deGrasse Tyson?

  They didn't fly.

• 34:54Chuck Nice?

  What you doing Tuesday? Let's take a walk.

• 34:56Neil deGrasse Tyson?

  Take off for a walk. So, there they were in Asia and there was a land and settlements there, we've come to learn. They crossed into North America after having risen up out of Africa.

• 35:08Chuck Nice?

  Right.

• 35:09Neil deGrasse Tyson?

  Risen up in terms of longitude, latitude here, but up out of Africa into Europe. Others went into Asia, some stayed low, others went high. They get to that boundary, they cross over and they settle North America, Central America and South America.

• 35:27Neil deGrasse Tyson?

  Then the Ice Age ends. Right. Okay.

• 35:31Chuck Nice?

  Oh my god. We're so trapped. What happened to the land bridge?

• 35:35Neil deGrasse Tyson?

  Well, no, that's long forgotten. Yeah. Okay, it happens kind of slow. Right. And then it covers over. Ah. All right. Many generations. All right, so what, yes, but you are correct. With the water levels rising, changing all the coastlines, has now stranded a branch, has now stranded a branch of the human species into North, Central, and South America. So we strand a branch of the human species into North and South America, and the water levels begin to rise. But at that time, the coastline of the Americas was that continental shelf. Right. Now imagine if people started building cities on that continental shelf. Ooh.

• 36:20Neil deGrasse Tyson?

  They'd all be gone today. No, what a shame. Okay, so what happens is, the Ice Age ends, and the end of the Ice Age is a mixture of warmth and cold. Hmm. Where the cold has retained glaciers for tens of thousands of years up here in Greenland. Right. And of course, down here. And Antarctica. Antarctica. And Antarctica. And so, that period is relatively stable. Yes, we have some storms and things, yes. Right. But, we have sustained one of the most

• 37:04Neil deGrasse Tyson?

  climatically peaceful periods in recent Earth history. Hmm. Ten thousand years of relatively stable climate. Mm-hmm. Post-Ice Age. Right. And when you're relatively stable, you say, oh, well, where is the coastline? Here is the coastline. Let's put New York there, or New Amsterdam. Right. Why? Because it's on a river. Right. You can have irrigation, you have transportation, you have, um, uh, uh, what else do you? Commerce. Commerce. Okay, business, all right. So, the coastline of all the world's nations today reflect

• 37:43Neil deGrasse Tyson?

  Ten thousand years of stable climate.

• 37:44Chuck Nice?

  Hmm.

• 37:46Neil deGrasse Tyson?

  The glaciers stayed glaciers in the cold parts.

• 37:49Chuck Nice?

  Right.

• 37:49Neil deGrasse Tyson?

  And other glaciers that had melted had filled up the oceans. It's been stasis, relative stasis. We are now warming Earth beyond that period of time.

• 38:01Chuck Nice?

  Yep.

• 38:02Neil deGrasse Tyson?

  And so the glaciers that are still there, that were in kind of equilibrium with us as we built civilization. And by the way, where are all major cities in the world? They're on the water's edge.

• 38:14Chuck Nice?

  On the right, on the coastline.

• 38:15Neil deGrasse Tyson?

  And practically, except for Denver, right?

• 38:17Chuck Nice?

  Right, yeah.

• 38:18Neil deGrasse Tyson?

  But practically every major city in the world.

• 38:21Chuck Nice?

  Right.

• 38:21Neil deGrasse Tyson?

  Famous historical city is on some kind of water line.

• 38:24Chuck Nice?

  That's right, yep.

• 38:25Neil deGrasse Tyson?

  Okay, so now we are warming the Earth. The glacial ice on Greenland, let's find Greenland right there. And the glacial ice on Antarctica. You say Greenland's not all that big and Antarctica's not, well, what are you worried about? Well, dab, dee, dab, dab.

• 38:41Chuck Nice?

  Big deal.

• 38:41Neil deGrasse Tyson?

  If we lose all the glacial ice in Greenland.

• 38:45Chuck Nice?

  Right.

• 38:46Neil deGrasse Tyson?

  It'll melt and go into what?

• 38:47Chuck Nice?

  The ocean.

• 38:48Neil deGrasse Tyson?

  The ocean. We melted on Antarctica.

• 38:51Chuck Nice?

  Ocean.

• 38:51Neil deGrasse Tyson?

  Goes into the ocean.

• 38:52Chuck Nice?

  That's right.

• 38:53Neil deGrasse Tyson?

  Raising the sea level.

• 38:54Chuck Nice?

  Rising sea level.

• 38:55Neil deGrasse Tyson?

  Okay, if we lose all that glacial ice, the oceans will rise. Now, the Statue of Liberty is actually on a huge pedestal.

• 39:03Chuck Nice?

  Right.

• 39:03Neil deGrasse Tyson?

  I don't know if you knew that. It's huge. Almost as big as.

• 39:06Chuck Nice?

  As the bottom of the statue.

• 39:07Neil deGrasse Tyson?

  At the bottom of the statue.

• 39:08Chuck Nice?

  Yeah, no, that's what she sits on. That's what raises up out of the bay.

• 39:11Neil deGrasse Tyson?

  Exactly.

• 39:11Chuck Nice?

  Right.

• 39:12Neil deGrasse Tyson?

  So the water levels will rise so high that it'll reach her left elbow.

• 39:17Chuck Nice?

  That's crazy. That means there will be no, no more Manhattan.

• 39:21Neil deGrasse Tyson?

  Yeah, yeah, yeah, you lose New York.

• 39:22Chuck Nice?

  You lose New York.

• 39:23Neil deGrasse Tyson?

  You lose.

• 39:23Chuck Nice?

  You lose all of North Jersey. You lose, not that anybody cares. Let's be honest.

• 39:29Neil deGrasse Tyson?

  Said no one ever, we lose New York and we lose North Jersey too. Said no one ever in the history of climate conversation.

• 39:37Chuck Nice?

  Who invited this guy? The dude from Jersey.

• 39:41Neil deGrasse Tyson?

  But my mama lives in North Jersey. So you lose all of that.

• 39:45Chuck Nice?

  Yeah.

• 39:46Neil deGrasse Tyson?

  And it's a different coastline.

• 39:48Chuck Nice?

  It is.

• 39:48Neil deGrasse Tyson?

  It's a coastline.

• 39:49Chuck Nice?

  Once again.

• 39:49Neil deGrasse Tyson?

  Without Florida.

• 39:50Chuck Nice?

  There you go. Oh, so there's one good thing the climate changed.

• 39:54Neil deGrasse Tyson?

  Stop, no, stop, stop. Stop, we gotta protect all our 50 states. So I think the average elevation of Florida is six feet.

• 40:02Chuck Nice?

  Oh, forget it. Say goodbye Florida.

• 40:05Neil deGrasse Tyson?

  You know, Florida has the lowest, highest elevation of all 50 states.

• 40:10Chuck Nice?

  Wow, right.

• 40:12Neil deGrasse Tyson?

  Can you follow that sense?

• 40:12Chuck Nice?

  That makes sense, because New Orleans is like below sea level, so Florida has the lowest, highest elevation.

• 40:18Neil deGrasse Tyson?

  No, no, but in Louisiana, their highest elevation is way higher than the highest elevation of Florida.

• 40:23Chuck Nice?

  Right, that's, yeah.

• 40:24Neil deGrasse Tyson?

  That's what I'm saying.

• 40:24Chuck Nice?

  Yeah.

• 40:25Neil deGrasse Tyson?

  No, you can have places with low elevation, I'm talking about the average.

• 40:27Chuck Nice?

  The average.

• 40:27Neil deGrasse Tyson?

  Okay, so.

• 40:28Chuck Nice?

  Well, six feet would do it.

• 40:30Neil deGrasse Tyson?

  Six feet, if you start with six feet, you ain't got nothing.

• 40:33Chuck Nice?

  Exactly, it's like, yeah, so basically, uh, your elevation is chuck plus an inch.

• 40:42Chuck Nice?

  You in a lot of, you in a lot of trouble, man.

• 40:45Neil deGrasse Tyson?

  If you fly over, uh, there's some satellite shots over Florida, and with the sun in the right angle, at the correct angle, you see these reflections off of these bodies of water throughout Florida.

• 40:57Chuck Nice?

  Right.

• 40:58Neil deGrasse Tyson?

  So, of course, there's the Okeechobee Lake, which is the big one right there in the middle. But you look around, it's like a body of water, body of water, body of water. So the, it's like the water is already ready to take over.

• 41:07Chuck Nice?

  Yeah, it's like, we're just, we're waiting.

• 41:11Neil deGrasse Tyson?

  One day, we will all join with one another.

• 41:13Chuck Nice?

  Bide your time, fellas.

• 41:16Chuck Nice?

  Uh, time is at hand.

• 41:18Neil deGrasse Tyson?

  We have invited the oceans to join us.

• 41:21Chuck Nice?

  The oceans are on board. All we need now is time, and they're resolved not to do anything.

• 41:27Neil deGrasse Tyson?

  Their human stupidity.

• 41:28Chuck Nice?

  That's it.

• 41:28Neil deGrasse Tyson?

  So that's a whole other coastline.

• 41:30Chuck Nice?

  Look at that.

• 41:31Neil deGrasse Tyson?

  So that's a whole other coastline.

• 41:32Chuck Nice?

  Right.

• 41:32Neil deGrasse Tyson?

  Of the future.

• 41:33Chuck Nice?

  Look at that.

• 41:33Neil deGrasse Tyson?

  And so now, you're gonna look down on Earth, and there's no, there's nothing inherent about the existence of Florida. On Earth's surface.

• 41:41Chuck Nice?

  Right.

• 41:41Neil deGrasse Tyson?

  That's my point.

• 41:42Chuck Nice?

  And. There you go.

• 41:44Neil deGrasse Tyson?

  And there are other parts, we'll lose a lot of, in northern Canada, there's a lot of sort of low, low-lying lands. Almost all of the South Pacific island nations are gone.

• 41:57Chuck Nice?

  Right.

• 41:57Neil deGrasse Tyson?

  Uh, they, they also have very low elevations.

• 41:59Chuck Nice?

  Get your vacations in now.

• 42:01Neil deGrasse Tyson?

  Get your vaca-, uh, Florida, as we said, we lose Florida, the Florida Keys, in fact, have even a lower elevation than Florida itself.

• 42:08Chuck Nice?

  That's a shame.

• 42:08Neil deGrasse Tyson?

  So they're gone, and Ken is gone, we're gonna lose Ken.

• 42:10Chuck Nice?

  Right.

• 42:11Neil deGrasse Tyson?

  I think he hung out at the Florida Keys.

• 42:12Chuck Nice?

  Yeah, exactly.

• 42:13Neil deGrasse Tyson?

  You know, so, so anyhow, I just want to impress upon you that when we think of Earth.

• 42:21Neil deGrasse Tyson?

  There's nothing inherent about the existence of land poking up above the existence of water.

• 42:29Chuck Nice?

  Right.

• 42:30Neil deGrasse Tyson?

  The water levels have changed over time and they're changing now and they're gonna redraw the map once again.

• 42:37Chuck Nice?

  Cool. And not cool. Like, it's a great novel thing to know and consider, but it's also terrifying that, um, we, the difference is, that was a natural engineering of coastlines that you explained before.

• 42:55Neil deGrasse Tyson?

  Mm-hmm.

• 42:55Chuck Nice?

  That's a natural engineering of coastlines. What we have now is a anthropomorphic engineering.

• 43:04Neil deGrasse Tyson?

  Right. And in fact, like I said, we grew civilization on a stable climate and a stable coastline.

• 43:10Chuck Nice?

  Right.

• 43:10Neil deGrasse Tyson?

  And, and that took thousands of years before that to get to that point and stabilize out.

• 43:16Chuck Nice?

  Right.

• 43:16Neil deGrasse Tyson?

  And now, on a time scale of decades.

• 43:19Chuck Nice?

  Decades.

• 43:20Neil deGrasse Tyson?

  Decades.

• 43:20Chuck Nice?

  We're looking at maybe changing all of that.

• 43:23Neil deGrasse Tyson?

  All of that.

• 43:23Chuck Nice?

  Yeah. Whoa.

• 43:24Neil deGrasse Tyson?

  There you have it.

• 43:25Chuck Nice?

  That is...

• 43:26Neil deGrasse Tyson?

  Alright, so Chuck, I don't mean to bum you out like that, I'm just saying.

• 43:30Chuck Nice?

  I'm so sad right now. I'm so sad.

• 43:34Neil deGrasse Tyson?

  In fact, one last thing, this is neither here nor there. When we talk about how much water is on a body, the way geologists refer to it is, how deep is the water if the water was the same depth everywhere on its surface? It's just, it's just a way to think about how much water is there.

• 43:51Chuck Nice?

  Right.

• 43:51Neil deGrasse Tyson?

  Right? So if you take the water and spread it smoothly, like, like icing on a cake, and, so no, it's not filling in the low parts or trickling off the high parts, it's having to go everywhere, how, how much would it be? So you can say, well, how much water did Mars have? If you give an answer to be in those terms, it would have fifty feet of water, a thousand feet of water, or ten feet of water. You'll just do this. Conduct this exercise. When you do it, you learn things like Europa, one of Jupiter's moons, which is frozen on the outside and liquid underneath. You add up that liquid, it's more liquid than all the oceans on, in, on Earth.

• 44:27Chuck Nice?

  Wow.

• 44:28Neil deGrasse Tyson?

  And since all our evidence tells us life began in the oceans, that's why we're, we can't wait to get our hands on that ocean.

• 44:35Chuck Nice?

  Right.

• 44:35Neil deGrasse Tyson?

  To see if there's any life forms.

• 44:36Chuck Nice?

  Yeah.

• 44:37Neil deGrasse Tyson?

  Uh, on Europa, which we would have to then call them.

• 44:40Chuck Nice?

  Europeans.

• 44:40Neil deGrasse Tyson?

  Europeans, right. Cause that's with life on Europa.

• 44:43Chuck Nice?

  What you wanna do, or we could just call them, you know, space white people.

• 44:47Neil deGrasse Tyson?

  What?

• 44:48Chuck Nice?

  They're Europeans.

• 44:49Neil deGrasse Tyson?

  Oh, if they're Europeans.

• 44:52Chuck Nice?

  Don't, they're jokes. They're jokes, people. Stop it.

• 44:57Neil deGrasse Tyson?

  So that's it.

• 44:58Chuck Nice?

  Okay.

• 44:58Neil deGrasse Tyson?

  Chuck, that's yet another StarTalk explainer, delivered to you from the Cosmic crib.

• 45:04Chuck Nice?

  Aha.

• 45:04Neil deGrasse Tyson?

  Yeah, at the American Museum of Natural History Hayden Planetarium. Neil deGrasse Tyson here, as always. Keep looking up.