Cosmic Queries: The Great American Eclipse

Neil deGrasse Tyson, Chuck Nice, and broadcast meteorologist Joe Rao are here with everything you need to know about the August 21st total solar eclipse, called “the Great American Eclipse.” Keep looking up – but only with eclipse-safe glasses! NOTE: StarTalk All-Access subscribers can watch or listen to this entire episode commercial-free. Find out more at https://www.startalkradio.net/startalk-all-access/

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.

• 0:22Neil deGrasse Tyson?

  Welcome to StarTalk. I'm your host Neil deGrasse Tyson, your personal astrophysicist. And we're recording this out of the world headquarters of Mashable, right here in New York City. And today, we're going to tell you everything you ever wanted to know, and perhaps what you didn't even want to know, about the upcoming great American eclipse.

• 0:41Chuck Nice?

  America.

• 0:41Neil deGrasse Tyson?

  American eclipse. Co-host is Chuck Nice.

• 0:44Chuck Nice?

  Hey buddy.

• 0:44Neil deGrasse Tyson?

  Chuck, love you man.

• 0:46Chuck Nice?

  Love you too, man.

• 0:46Neil deGrasse Tyson?

  And he also hosts the spinoff of StarTalk, Playing with Science.

• 0:51Chuck Nice?

  That's correct, Playing with Science. That's right.

• 0:53Neil deGrasse Tyson?

  When you play with science, I should... Did you get permission to play with science?

• 0:59Chuck Nice?

  Has your mother caught you playing with science Chuck? Hey, there's a lock on that door for a reason!

• 1:05Neil deGrasse Tyson?

  Don't you know that can make you go blind?

• 1:10Neil deGrasse Tyson?

  So just to remind you, because I'm not in that show.

• 1:12Chuck Nice?

  So no, Playing with Science, it's Gary O'Reilly, who was a former footballer, and Chuck Nice, who is some guy, and we actually have different athletes on the show, and we take what somebody says where jocks and geeks collide, without a concussion. Without a concussion. It's amazing. And so what we do is we take sports and science, and we break down the science in the sports, and we discuss the sports as well. It's a lot of fun.

• 1:43Neil deGrasse Tyson?

  It's a recent spinoff. That's why I'm still learning about what you guys cooked up over there. So, but thanks for joining us.

• 1:48Chuck Nice?

  Absolutely.

• 1:49Neil deGrasse Tyson?

  And you know what we have today? By video call, we have an expert guest, who's my friend and colleague, and an associate at the Hayden Planetarium, Joe Rao. Joe!

• 2:00Neil deGrasse Tyson?

  Thanks for being on. You're a broadcast meteorologist and you wrote the children's book Looking Up: The Science of Stargazing.

• 2:09Chuck Nice?

  Absolutely.

• 2:10Neil deGrasse Tyson?

  Yeah, yeah, it's good to have you. Always good to get your input on nighttime cosmic phenomena. In this case, it would be daytime phenomena. And in particular, this episode of StarTalk is officially designated a Cosmic Queries just on the eclipse.

• 2:27Chuck Nice?

  Just on the eclipse.

• 2:28Neil deGrasse Tyson?

  Yeah, so we'll go to Cosmic Queries intermittently, but I want to get sort of Joe in the mix here. Joe, I've seen one eclipse in my life. You've seen some uncountable number of eclipses. How many total minutes of totality have you been steeped in?

• 2:43Chuck Nice?

  Well, I've always said total eclipses, when you see it first, it's like potato chips. You become addicted. You have to have more. And quite obviously, I've been addicted because I've seen 11, this will be my 12th, and I hope to see a lot more before I depart this earth.

• 2:59Neil deGrasse Tyson?

  Well, I'll be going media silent during the eclipse, which will force the media into the thousands of people who walk this land, who have expertise sufficient to deliver an interview with the press.

• 3:12Chuck Nice?

  But you know they're still gonna call you. You know that, right? Seriously.

• 3:16Neil deGrasse Tyson?

  No, no, because they get lazy and just call me because I live here in New York City. And they know I can give them a sound bite. But this event will sell itself, and so that's why I don't need to be there. And my location is a state secret.

• 3:29Chuck Nice?

  Oh, really?

• 3:30Neil deGrasse Tyson?

  You will not know where I am on earth. You'll know I'll be in the path of totality, but you won't know where I am on earth or my elevation above earth.

• 3:37Chuck Nice?

  And you know what's funny is I get asked every day on Twitter where you are going to go watch the eclipse, and to which I...

• 3:43Neil deGrasse Tyson?

  And in case you get tortured, I don't want you to know.

• 3:46Chuck Nice?

  Right, well, I tell people all the time, Neil doesn't like me. He tells me nothing. We just work together. What is your problem?

• 3:55Neil deGrasse Tyson?

  So Joe, I'm looking in, that's your, your office in the back there with all these degrees on the wall. So Joe's wicked smart.

• 4:02Chuck Nice?

  Yeah.

• 4:02Neil deGrasse Tyson?

  Um, and you got a total eclipse in the upper corner there, or is that a black hole?

• 4:07Speaker 02

  No, no, that's, that's a view of a total eclipse of the sun. I don't know exactly. Actually, I have a total eclipse, an annular eclipse, and I have an eclipse that was taken by a gentleman from the Amateur Astronomers Association right here in New York. Uh, he is no longer with us. That dates back to 1945 over Montana. The rising sun over the hills of Montana, it's a crescent sun and a few minutes after sunrise, it went into total eclipse and uh, they're, they're amazing.

• 4:36Chuck Nice?

  That is gorgeous. That, you can't beat that. It's like, uh, the sunrise and, or is it nature's way of saying, I just robbed you of a sunrise?

• 4:48Neil deGrasse Tyson?

  So Joe.

• 4:48Speaker 02

  You know, it's, it's interesting, uh, the, the next total eclipse of the sun over little old New York will be on Tuesday, May 1st, 2079, and that happens right after the sun comes up. So if it's clear that morning, it'll be a most, probably the most unusual sunrise in New York history. Uh, again, if it happens to be clear.

• 5:07Neil deGrasse Tyson?

  He's speaking that like we're all gonna be alive.

• 5:09Chuck Nice?

  I'll be sure to mark my calendar.

• 5:11Neil deGrasse Tyson?

  Put that, put that on my smartphone now.

• 5:16Neil deGrasse Tyson?

  So Joe, uh, spend a minute just describing what the hell is gonna happen.

• 5:21Speaker 02

  Well, actually, uh, at the very beginning, you don't even know that it's happening. If you're not aware that there's an eclipse that is gonna take place, a total eclipse of the sun, what happens is that the moon begins to move in front of the sun. And actually, you have to have a considerable amount of the sun covered before you start noticing that something eerie is happening. The landscape, after about 70 or 80% of coverage, the landscape begins to take on kind of a weird look, uh, more of a yellowish color, almost like a dusky twilight beginning to descend upon. The entire region, but it's not until that last thirty seconds, the last thirty seconds before totality, that it really gets crazy. Uh, it's almost like being at a Broadway

• 6:06Speaker 02

  play, curtain time at a Broadway play. And you know, if you've been to a Broadway play, they lower the lights very quickly, just as the show's about to begin. That's kinda like what it is just before totality. All of a sudden, the sky begins to darken very quickly, and then suddenly, up in the sky where there was once a brilliant ball of light, the sun, you now have this strange eye, if you will, wind with fire appearing in the middle of the sky. And stars come out, the sky gets a quality similar to twilight, half an hour or forty-five minutes after sundown. Uh, and it's just an awesome, awesome spectacle. And it only lasts for, depending about where you are in the eclipse path, only

• 6:48Speaker 02

  about a minute or two, in this case, at most, two minutes and forty seconds. And then after that, we just reverse the procedure. In thirty seconds, up comes the lights, and within a minute or two, it's almost as if there were, nothing had happened prior. Uh, it's back to a normal sunny day. And it just, it floors everybody who sees it for the first time. And I think a lot of people are gonna be just stunned about what, what's gonna occur on August twenty-first, that streaks across, uh, United States from coast to coast.

• 7:18Neil deGrasse Tyson?

  So, so, um, Joe, I hadn't appreciated this until you just said it now. We, there's nothing in life experience that darkens a daytime sky as quickly as the last few seconds of the partial phases of a total eclipse. Because when the sun sets, it's slightly darker, but it's not pitch black.

• 7:39Speaker 02

  Right.

• 7:39Neil deGrasse Tyson?

  And some people think it gets immediately dark at sunset.

• 7:42Speaker 02

  Right.

• 7:43Neil deGrasse Tyson?

  Because they've never paid attention.

• 7:44Speaker 02

  Exactly.

• 7:44Neil deGrasse Tyson?

  Right. I've had lawyers call me up and say, someone is testifying that they couldn't see anything when they were driving because it was five minutes after sunset. I said, there's a liar.

• 7:54Speaker 02

  A liar.

• 7:57Neil deGrasse Tyson?

  So here we have an eclipse where a few percent of the sun exposed is sufficient to just be kind of bright daylight and then bam darkness descends upon the deep.

• 8:08Speaker 02

  A lot of people, a lot of people say, you know, what's the big difference? I'm gonna see a ninety-five or ninety-seven percent partial eclipses. They're really the necessity to get into the zone where it's gonna be total. And my answer to that is, most unequivocally, yes, yes, you do wanna get into the total band of totality because if you don't, you're gonna miss out on a lot. People are amazed, even as you just mentioned Neil, the final couple of percent of sunlight, even if it's a razor-thin crescent, still puts out a large amount of sunlight, a large amount of illumination. You gotta shut off every little bit of the sun in order to appreciate just how much darker it gets. And with that few percentage points of sunlight remaining, you don't see the stars come out.

• 8:53Speaker 02

  You don't get that dramatic sunset and sunrise color rimming the horizon and you don't see that, that shadow, the lunar shadow, comes sweeping in and over you like somebody throwing a blanket over your head. You really miss out unless you get into that zone of totality and I think, I think that's gonna lead to a, to a tremendous number of people trying to do that on Monday, the twenty-first of August.

• 9:16Neil deGrasse Tyson?

  So, so it's been said once and I, and I forgot who said it and I'm gonna have to paraphrase it. So, it's the difference between seeing a partial eclipse and seeing a total eclipse is equivalent to the difference between kissing your loved one and having sex with your loved one.

• 9:39Chuck Nice?

  I love this analogy.

• 9:40Neil deGrasse Tyson?

  Because, because you, they're both pleasing.

• 9:46Chuck Nice?

  They're both pleasing.

• 9:47Neil deGrasse Tyson?

  But.

• 9:48Chuck Nice?

  I'll take either one.

• 9:49Neil deGrasse Tyson?

  You, you cannot extrapolate.

• 9:50Chuck Nice?

  Right.

• 9:51Neil deGrasse Tyson?

  From the kiss to sex. There's no path to land there. It is a completely, it's completely more.

• 10:00Chuck Nice?

  Absolutely.

• 10:01Neil deGrasse Tyson?

  It's a whole, it's here.

• 10:02Chuck Nice?

  Yes, exactly. It is, it is, right, yeah, yeah, exactly. One is like eating the best, most exotic delicacy you could ever find and the other is like licking carpet.

• 10:19Chuck Nice?

  So. No, Lincoln Carpet is unplugged. Yeah, that's true. They both have to be good. They both have to be good. That's why this analogy was good. This analogy was good. I just screwed it up. You just messed up bad.

• 10:28Speaker 02

  How about, how about being, how about being outside, you know, you, you, before World Series? Seeing a partial eclipse is like being in the parking lot. Seeing a total eclipse is taking your ticket, walking into the stadium and sitting down in the box seat and getting ready to actually watch physically the game.

• 10:45Chuck Nice?

  And then.

• 10:46Speaker 02

  It's both exciting.

• 10:46Chuck Nice?

  And then having sex in the seventh inning stretch. There you go. There you go. Now we got. There's a total eclipse. Total eclipse. Joe, what makes this America's eclipse?

• 11:00Speaker 02

  It's called, it's being called the Great American Eclipse because number one, it's the first time since 1918 that this eclipse is going to be going from coast to coast. In 1918, we had one that came in from the Pacific coast and went across the United States, ended up going through Florida, exiting out over the Bahamas in 1918. So that wasn't a full American eclipse because it did touch places outside of American soil. This one is being called the Great American Eclipse because we're the only hot country. We are the host of this eclipse. There have been other eclipses in the past, like for example, in 1970, there was one that went through Mexico,

• 11:42Speaker 02

  went up along the eastern seaboard of the United States and then went into eastern Canada, the Maritimes. 1979.

• 11:47Chuck Nice?

  Wait, wait, wait. Did that 1970 eclipse, that was the Carly Simon eclipse, correct?

• 11:52Speaker 02

  Uh, no, I think the Carly Simon eclipse was 1972, actually. Uh, it could have been the 1970 eclipse. It could have been the 1970.

• 12:00Chuck Nice?

  You guys can't go any further now. You just have to. The Carly Simon eclipse? What, is that an eclipse that looks at you and says like, oh, you think this is about you?

• 12:11Chuck Nice?

  What kind of a, what's the Carly Simon eclipse? Okay, Joe, explain.

• 12:15Speaker 02

  You're so vain, right? Right? The, the song, you're, the Carly Simon song, You're So Vain. And she apparently writes about somebody, some mysterious person who went to fly his Learjet to Nova Scotia to see a total eclipse of the sun.

• 12:29Chuck Nice?

  It's a lyric in the song. Oh, okay.

• 12:32Speaker 02

  That could have been one of three eclipses. There was one over Nova Scotia in 1963. There was one in 1970. I personally think it was the one in 1972. July, that was also my very first total eclipse. I saw that one from Quebec, but after it passed over me in Quebec, it went across Nova Scotia. And I think the, the song, Carly Simon's song was a hit the following year in 1973, which makes me think that maybe she was talking about that 1972, or maybe she was just making the whole thing up. Who knows?

• 13:00Chuck Nice?

  No, the song's about Ned Beatty, I think, so. Ned Beatty? No, I'm sorry. Warren Beatty. These are two different Beatties. Yeah, nobody would ever write a song about Ned Beatty. What the heck is my problem?

• 13:15Speaker 02

  Well, this eclipse, this eclipse is gonna be the great American eclipse because we are the host country. There's no other country that we're sharing this eclipse with. And the last time that happened was before this country became a country. Uh, if you go back over the various, uh, manuals that show you tracks of past eclipses, historical eclipses, the last time this country, if you use the political boundaries, had an eclipse all to its own, was back in the year 1245 A.D. So, uh, and that was of course before the United States existed. So this is the very first time that we are the sole country and there are countries, uh, people from all over the world that are gonna be converging on just the United States for this great American eclipse.

• 13:57Chuck Nice?

  It's just one more way that we're making America great again. I'm taking total credit for this eclipse.

• 14:09Speaker 02

  By the, by the way, did either of you know that Donald Trump, President Donald Trump, was born on the day of the eclipse? He was born on the day, he was born on the day of, he was born on the day of a total eclipse of the moon, Donald Trump. I haven't had a chance to look and see if any other president has had. A total eclipse or a- any eclipse on, on his birth day, but Donald Trump has that, uh, that recognition of being born on the day when there was a total eclipse of the moon.

• 14:37Neil deGrasse Tyson?

  Just to be clear, an eclipse of the moon takes place at the moon.

• 14:42Chuck Nice?

  Right.

• 14:42Neil deGrasse Tyson?

  An eclipse of the sun takes place at the earth. So if you are anywhere on the side of the earth that sees the moon being eclipsed.

• 14:50Chuck Nice?

  Right.

• 14:51Neil deGrasse Tyson?

  You will see the total eclipse of the moon.

• 14:52Chuck Nice?

  Okay.

• 14:53Neil deGrasse Tyson?

  Okay.

• 14:53Chuck Nice?

  Gotcha.

• 14:54Neil deGrasse Tyson?

  So anyone, so that's a lot of people that it could be.

• 14:57Chuck Nice?

  That could, right, absolutely.

• 14:58Neil deGrasse Tyson?

  So it's not as rare a thing.

• 15:00Chuck Nice?

  Right.

• 15:00Neil deGrasse Tyson?

  To be born under an eclipsing moon as it is to be born under eclipsing sun.

• 15:05Chuck Nice?

  Either way, I'm so great, I block out the sun.

• 15:10Neil deGrasse Tyson?

  So, so Joe, is the, um, the, so what's an average totality among eclipses relative to this one?

• 15:20Speaker 02

  Well, I mean, it's, I, I think even just a, a one second to- total eclipse is more amazing than anything that you'll ever see in terms of a partial eclipse. Um, and this one, this one, actually I've been telling people, this is actually the appetizer. This upcoming eclipse this year, because there's going to be another total eclipse over the United States in 2024. Only seven years down the road. And that eclipse is going to be better in the sense that the path, the area of visibility of the total phase of the eclipse is going to be bigger. As I mentioned earlier, this one is not going to last longer than two minutes and 40 seconds. The one in 2024 is going to last in some places over four minutes.

• 16:02Speaker 02

  So whereas people will probably get turned on when they see this eclipse in 2017. And the first thing out of their mouths will say, when can I see another one? Seven years from now, 2024, you'll get another one, and that one will be even better. Much better, in fact, circum- in terms of circumstances than what we're going to see this year in 2017.

• 16:20Neil deGrasse Tyson?

  So you get these differences because of the distance that the moon is from earth.

• 16:24Chuck Nice?

  Right.

• 16:24Neil deGrasse Tyson?

  Is not constant.

• 16:25Chuck Nice?

  Is that because it's like, what, what, what would you call it? Is it like a depth of field when you're looking at something from a distance and you're like, you use your thumb to block it out? That type of deal?

• 16:36Neil deGrasse Tyson?

  Yeah, okay, but, so, so, yeah, if the moon is close, in the moon's elliptical orbit around the earth. If, if we get an eclipse when the moon is closer to earth.

• 16:45Chuck Nice?

  Right.

• 16:45Neil deGrasse Tyson?

  Then the moon is bigger in the sky.

• 16:46Chuck Nice?

  Right.

• 16:47Neil deGrasse Tyson?

  And if at that time we are farther from the sun, because our orbit around the sun is also elliptical.

• 16:53Chuck Nice?

  Correct.

• 16:53Neil deGrasse Tyson?

  So the eclipse that I saw. Way back when, had the moon at one of its closest times to Earth, and Earth at one of its farthest distances from the Sun.

• 17:03Chuck Nice?

  Uh-huh.

• 17:03Neil deGrasse Tyson?

  So it took a long time for the Sun, for the moon to pass in front of the Sun.

• 17:08Chuck Nice?

  So, okay, gotcha.

• 17:09Neil deGrasse Tyson?

  So my eclipse at peak was seven minutes and 14 seconds.

• 17:12Chuck Nice?

  Oh my God. That is amazing.

• 17:15Neil deGrasse Tyson?

  Yeah, so that's at peak, but we couldn't go to where it was peaking because there was a dust storm kicking up over this Sahara, okay? And so, we saw it off, uh, off, more off the coast. So mine was six minutes and 20 seconds.

• 17:28Chuck Nice?

  Speaking of which, and since Joe, uh, is meteorologist, can, is there a place where you don't want to go because if it's cloudy, you are screwed?

• 17:40Neil deGrasse Tyson?

  We will touch on that when we come back from this commercial break on StarTalk.

• 17:52Neil deGrasse Tyson?

  We're back on StarTalk. I'm Peter Ross Tyson, Chuck Nice. Me, meeting at Chuck Nice Comic.

• 17:57Chuck Nice?

  Thank you, sir. Yes, sir.

• 17:59Neil deGrasse Tyson?

  Uh, we've got with us on video call, the one, the only, the guy who knows the nice guy better than anyone I've ever met, Joe Rao, an associate at the Hayden Planetarium. Uh, and he's a meteorologist, uh, who, like, lifetime television meteorologist.

• 18:14Chuck Nice?

  Yeah.

• 18:15Neil deGrasse Tyson?

  He's got that meteorologist's voice, too.

• 18:16Chuck Nice?

  He does.

• 18:17Neil deGrasse Tyson?

  Let me hear some of that voice, Joe.

• 18:19Speaker 02

  Uh, I, this morning for breakfast, I had some eggs vorticity.

• 18:22Neil deGrasse Tyson?

  Very good, okay.

• 18:25Chuck Nice?

  Very nice.

• 18:27Neil deGrasse Tyson?

  So, uh, just before the break, we were trying to get it, uh, understand a couple of things, but let me, let me back up for a minute. Today, people travel with much greater ease than at any time in the history of eclipses. So, is it possi- possible that this eclipse will be the most watched ever in the history of civilization?

• 18:48Chuck Nice?

  Hmm.

• 18:49Neil deGrasse Tyson?

  Because this is America, and everybody's got a car.

• 18:51Chuck Nice?

  Right.

• 18:52Neil deGrasse Tyson?

  And if you don't drive, you'll have a plane, or whatever, and we all will just gather in this path of totality, this narrow path across the country.

• 19:01Speaker 02

  Well Neil, there are 12 million people who already fortuitously live in the zone of totality. They get that for free. Yeah, exactly.

• 19:10Speaker 02

  It's 70 miles wide, it's 2,500 miles long, stretching from Oregon to South Carolina. However, there are an estimated 220 million people, that's more than two thirds of the total population of the United States, 220 million are within a one day's drive, 500 miles of the total eclipse path, which leads one to wonder just how many people either late that Sunday night, the night before, or early that Monday morning, the 21st of August, are gonna suddenly decide, "Hey, let's jump in the car and go and see that total eclipse." So it's gonna be interesting to see, there are a lot of, in fact, of the 14 states that

• 19:50Speaker 02

  are in the totality zone, the DOT, the Department of Traffic, has issued in all of those states warnings as if it were almost like a category 3 hurricane heading in their direction. They are warning about major traffic jams, stock up on food because you're gonna be in your car for a long time, and even on some of the major interstate roads like I-85 in Georgia, or I-5 in Oregon, they're anticipating traffic tie-ups that they have never seen before, for all these people trying to jockey into position to see the total eclipse that day.

• 20:25Neil deGrasse Tyson?

  So, so it's possible that 200 million people will see this eclipse? Do you think that that's more than any previous eclipse has ever been witnessed?

• 20:31Speaker 02

  I'm not sure, I know that in 1991...

• 20:35Neil deGrasse Tyson?

  That's the Mexico City eclipse.

• 20:37Speaker 02

  The 1991 eclipse was related to the one that you saw Neil, in back in the 70s.

• 20:42Neil deGrasse Tyson?

  The same sunrise, yeah.

• 20:43Speaker 02

  A very long eclipse, yeah, it was about 7 minutes long, it passed over Mexico City. The entire population of Mexico City was treated to a total eclipse, and I believe at that time, the population of Mexico City in one sitting was like 23 million people.

• 20:57Neil deGrasse Tyson?

  Wow.

• 20:58Speaker 02

  Um, so, it may not be necessarily in one sitting for this eclipse, but certainly, if a lot of people travel into the totality path, this could very well be indeed the most viewed eclipse, total eclipse, in modern history.

• 21:12Neil deGrasse Tyson?

  No, in all of history.

• 21:15Speaker 02

  In all of history, yeah.

• 21:16Neil deGrasse Tyson?

  Yes, and if I remember, the 1991 eclipse also went across Mauna Kea, Hawaii, and the telescope was able to observe it from there, wasn't that the same eclipse?

• 21:28Speaker 02

  Yeah, they, in fact, it passed over the big island of Hawaii and Mauna Kea is there on the top of that extinct volcanic cone. The problem was, they saw it at Mauna Kea, but all the people who went to Hawaii to see that eclipse, or most of the people who went to Hawaii, didn't. The, the, prior to the eclipse, the meteorologists and climatologists said, "Oh, there's a 95% chance of clear weather for the eclipse." Because in July, that was the month that the eclipse occurred, they get the trade winds, and when the trade winds blow, usually, the weather is clear. Absolutely. But unfortunately, on the day of the eclipse, it was the other 5%. There was some sort of disturbance which clouded things over and people actually got rained on in Hawaii.

• 22:11Speaker 02

  One person actually walked away after that, after the eclipse and said, "The total eclipse was a total bust, at least for Hawaiians." So, they were lucky that they did see it from Mauna Kea.

• 22:22Neil deGrasse Tyson?

  They're gonna blame you, Joe, you know that, right? They're all gonna blame you.

• 22:27Speaker 02

  Well, you know, you could look at all the weather records, you could see, you could see where the best place is based upon long-term records, but it doesn't always work out that way. In fact, Robert Heilman, who was a very famous science fiction writer, once said, and it's absolutely true, "Climate is what you expect, but weather is what you get." So, you, you may be in a place where the climatology says it'll be great for viewing the eclipse, but the weather makes up its own mind. If it decides to be cloudy that day and you don't see it, so goes.

• 23:00Neil deGrasse Tyson?

  Okay. So, before we get to cosmic queries, because this is a cosmic queries edition.

• 23:04Speaker 02

  Yeah.

• 23:05Neil deGrasse Tyson?

  So, Joe, why don't you just spend a couple of minutes explaining what it means to have families of eclipses? That there are groups of eclipses that are similar to one another?

• 23:13Speaker 02

  There is a, there is a family or cycle that was known to the ancient Chaldeans and Babylonians thousands of years ago, known as the Saros cycle. And what this is, is that it's a, there are three different lunar cycles that seem to come together. It's kinda like hitting the jackpot, let's say, on a slot machine. These three cycles involve the position of the moon in its orbit relative to the earth, whether it's closer or farther away, the lunar month, also known as the synodic month. These cycles all come together and it's called a seros cycle. Seros means repetition. And eclipses repeat after about eighteen years and ten or eleven and one-third days.

• 23:57Speaker 02

  That one-third of a day is important, however, because when the eclipse returns after eighteen some odd years, the earth in that one-third of a day has turned a hundred and twenty degrees in its rotation cycle. And so while the eclipse is going to return, it will not return to the same part of the world that it was seen eighteen years previous. This eclipse coming up, for example, the Great American Eclipse, eighteen years ago, eighteen years and about eleven and a third days ago, that eclipse occurred over Europe. Well, now eighteen years later, eighteen years and ten and a third days later, the earth has turned a hundred and twenty degrees, so now it's not over Europe. This time it's our turn here in the United States, or North America, to see that eclipse. And in another

• 24:40Speaker 02

  eighteen-plus years, the earth will turn again, one-third of a way around. So when this eclipse returns in eighteen years, that's in the year 2035, it won't be visible over North America. It'll probably be passing over the Pacific Ocean or parts of Asia. But this cycle was known thousands of years ago to the ancient sky watchers, and they were able to make some pretty good predictions just by knowing about the repetition of this eclipse cycle and being able to anticipate when eclipses were going to occur.

• 25:12Neil deGrasse Tyson?

  So the eclipse that I saw was in July of 1973, because that's how old I am.

• 25:19Speaker 02

  Okay.

• 25:20Neil deGrasse Tyson?

  Add eighteen and two-thirds years to that, you get to the 1991 eclipse.

• 25:25Speaker 02

  Eclipse.

• 25:25Neil deGrasse Tyson?

  Yeah, so that all works out. So Chuck, why don't you give us a question?

• 25:28Chuck Nice?

  All right, why don't we start off, and we'll, of course, we always start with one of our Patreon patron questions, because these are the people that support us financially.

• 25:36Neil deGrasse Tyson?

  I mean, they bought their way into the question list.

• 25:38Chuck Nice?

  I say it all the time, just like your congressman, we can be bought.

• 25:43Neil deGrasse Tyson?

  So...

• 25:46Neil deGrasse Tyson?

  Alright.

• 25:46Chuck Nice?

  Alright. Uh, this is Eric Varga coming to us from Facebook. "I'm aware that the moon is receding from the earth at a rate of a couple inches per year. How long will it be until the moon's orbit has moved too far to have any more total solar eclipses?"

• 26:05Neil deGrasse Tyson?

  Ooh!

• 26:06Chuck Nice?

  What an incredible question!

• 26:07Neil deGrasse Tyson?

  So the moon is getting smaller and smaller.

• 26:09Chuck Nice?

  That's right.

• 26:09Neil deGrasse Tyson?

  That means there will be a day where the moon will never in its orbit be large enough to completely cover the sun.

• 26:16Chuck Nice?

  Right.

• 26:17Neil deGrasse Tyson?

  They'll still have eclipses.

• 26:18Chuck Nice?

  Right.

• 26:18Neil deGrasse Tyson?

  They just won't be total.

• 26:19Chuck Nice?

  They just won't be total.

• 26:19Neil deGrasse Tyson?

  In fact, we... there's... the word for ring is annulus.

• 26:23Chuck Nice?

  Annulus.

• 26:23Neil deGrasse Tyson?

  That's a word for... Latin for a ring.

• 26:26Chuck Nice?

  Right.

• 26:26Neil deGrasse Tyson?

  And so, one of the kinds of eclipses is an annular eclipse.

• 26:30Chuck Nice?

  Annular, right.

• 26:31Neil deGrasse Tyson?

  Right, and where the sun... the moon goes in the center of the sun, you see a ring of sunlight. So, Joe, have you done this calculation? I haven't. I can take a stab at it.

• 26:39Speaker 02

  I haven't heard... There's a gentleman who lives in Belgium who's world-renowned. He's a very famous calculator of celestial mechanics, Jean Mayuss. And Dr. Mayuss has done the calculation, and he says that sometime about a billion or so years from now, the moon will indeed be too far away to create total eclipses. Actually, he says that it's gonna be a few million years where it's gonna alternate, where it'll be possible and then not possible. You'll get periods where, uh, the, uh... Uh, you'll go through periods where the moon will be too far away, and then it'll just be close enough to cover the sun. But, in about a billion years or so, according to Dr. Mayuss, that will be the time when eclipses of the sun, total eclipses of the sun,

• 27:23Speaker 02

  will just be a thing of the past. So, enjoy these spectacles while they last, because in about a billion years, they're gonna end.

• 27:30Neil deGrasse Tyson?

  By the way, uh, uh, four billion years ago, when the moon formed, it was 20 times larger in the sky than it is now.

• 27:42Chuck Nice?

  Wow.

• 27:42Neil deGrasse Tyson?

  So you would have some serious eclipses every, no, not eclipses again.

• 27:46Chuck Nice?

  Right, exactly.

• 27:47Neil deGrasse Tyson?

  Yeah, I gotta finish my homework.

• 27:48Chuck Nice?

  Yeah, it's just like, where'd the lights go again? Again?

• 27:51Neil deGrasse Tyson?

  Again!

• 27:51Chuck Nice?

  Who's not paying this bill?

• 27:52Neil deGrasse Tyson?

  Right.

• 27:53Chuck Nice?

  Who is not paying this bill?

• 27:54Neil deGrasse Tyson?

  Yeah, so the moon has been spiraling away over the billions of years.

• 27:57Chuck Nice?

  Right.

• 27:57Neil deGrasse Tyson?

  But the rate at which it spirals away will get slower. So it was, it was happening fast, long ago.

• 28:04Chuck Nice?

  Yeah.

• 28:04Neil deGrasse Tyson?

  Yeah.

• 28:05Chuck Nice?

  So that, that, that, that makes me, uh, curious about eclipses from the standpoint of other planets. So if there, is there another planet where, it seems as though we are uniquely situated for eclipses, that total solar eclipses, the way they happen here. Is there another planet in our solar system that might have maybe a couple moons that do the same thing? Or that align at the same time? Or, you know, that might give us some, some different configurations of an eclipse?

• 28:36Neil deGrasse Tyson?

  Are you interjecting your own question from the cosmic query?

• 28:39Chuck Nice?

  I, I am interjecting.

• 28:40Neil deGrasse Tyson?

  Okay, that's allowed, because you're co-host, that's fine.

• 28:41Chuck Nice?

  Okay.

• 28:42Neil deGrasse Tyson?

  That's allowed.

• 28:42Chuck Nice?

  Good.

• 28:43Neil deGrasse Tyson?

  Uh, so, uh, an interesting fact about the moon and the sun. Is, is the number 300, Joe? The, the, the moon is, uh, the sun is 300 times farther away than the moon is? And the sun is...

• 28:54Speaker 02

  I think it's 400.

• 28:55Neil deGrasse Tyson?

  400. The, the sun is 400 times farther away from us than the moon is.

• 28:59Chuck Nice?

  Okay.

• 28:59Neil deGrasse Tyson?

  And the sun is 400 times larger than the moon.

• 29:02Chuck Nice?

  Ah.

• 29:02Neil deGrasse Tyson?

  So, cancels straight out.

• 29:04Chuck Nice?

  Straight out.

• 29:05Neil deGrasse Tyson?

  And they fit, and they're fit. So, anybody else have that ratio in the whole solar system, Joe?

• 29:10Speaker 02

  I don't think so. Um, and there are so many moons now. I mean, when you and I were growing up, Neil, it was so easy. Jupiter had 12, and Saturn had 10.

• 29:18Neil deGrasse Tyson?

  Couple dozen moons in the solar system.

• 29:19Speaker 02

  You know, the, now, now Saturn alone has like 67 moons, and Jupiter has like a similar amount. But I think all of those satellites that are going around all the other planets are probably too small to create the same type of effect as what we have here, uh, as seen from the Earth. In fact, you might even call the Earth-moon system a double planet. There's no moon, uh, that is proportionally, uh, as larger size as our moon is relative to the Earth, as opposed to all the other planets, uh, in the solar system that have, uh, satellites to create the spectacle of a total eclipse of the sun.

• 29:53Neil deGrasse Tyson?

  Now, before 2006, we would have said Pluto has a larger moon. Relative to itself, but since it's not a planet anymore.

• 29:59Chuck Nice?

  Right.

• 30:00Neil deGrasse Tyson?

  It's not in his answer.

• 30:01Chuck Nice?

  Exactly.

• 30:01Neil deGrasse Tyson?

  Right, because Pluto's moon Charon is even bigger compared to Pluto than our moon is compared to us.

• 30:06Chuck Nice?

  Right. So the size to distance ratio for Pluto, if it were a planet. Take that ice ball.

• 30:15Chuck Nice?

  Might make it uniquely situated to have what, to experience.

• 30:18Neil deGrasse Tyson?

  Yeah, I think, no, no, but the sun is really, really small out there, so.

• 30:21Chuck Nice?

  Yeah, because it's so far away.

• 30:22Neil deGrasse Tyson?

  It's so far away, so.

• 30:23Chuck Nice?

  Either way, it still doesn't really fit.

• 30:24Neil deGrasse Tyson?

  You get an eclipse, but if, if the eclipsing, if the object passing between you and the sun is really, really large.

• 30:30Chuck Nice?

  Right.

• 30:30Neil deGrasse Tyson?

  You're not gonna get the beautiful corona effect. Because that's right adjacent to the edge of the sun.

• 30:35Chuck Nice?

  It's like just closing your eyes, because it just blocks everything out.

• 30:38Neil deGrasse Tyson?

  Yeah, just closing your eyes, right.

• 30:39Chuck Nice?

  Just closing your eyes at that point.

• 30:40Neil deGrasse Tyson?

  Exactly.

• 30:40Chuck Nice?

  Wow.

• 30:41Neil deGrasse Tyson?

  Exactly.

• 30:41Chuck Nice?

  Dude, that was great. Awesome. Alright.

• 30:43Neil deGrasse Tyson?

  One minute left?

• 30:44Chuck Nice?

  We got one minute left.

• 30:44Neil deGrasse Tyson?

  In this segment.

• 30:45Chuck Nice?

  Alright, you know what? So, since we got one minute left, I'm gonna give you a, um.

• 30:52Chuck Nice?

  Okay, I gotta do this, because it's, I gotta ask you this question just because Andrew Hanks wants to know this. And I'm taking him seriously, okay? Will the sun melt the moon when it passes in front of it? I'm, uh, I'm not too keen on cheese, and I don't fancy it raining down on me when I, uh, when I, uh, go shopping.

• 31:14Chuck Nice?

  I did not make that up. Andrew Hanks wants to know, will the moon, will the sun melt the moon? When it passes in front of it?

• 31:23Neil deGrasse Tyson?

  Okay, here's the thing. Given.

• 31:24Chuck Nice?

  I'll take that.

• 31:25Neil deGrasse Tyson?

  Given how many people think today that Earth is flat.

• 31:29Chuck Nice?

  Right.

• 31:29Neil deGrasse Tyson?

  This is a high level question.

• 31:34Neil deGrasse Tyson?

  I'm impressed, we're getting better. At least it's thinking about the thermodynamics of the situation.

• 31:39Chuck Nice?

  Absolutely. See, that's why I asked it, because I knew, and no matter what, Neil will find a way to answer someone's question. I don't care how stupid it is. And I know they say there's no such thing as stupid questions, but the people who say that are stupid, so.

• 31:56Neil deGrasse Tyson?

  So, Joe, I'll take this one. So here it is. So, on the side of the moon that is facing the sun. It's a couple hundred degrees. It's very hot.

• 32:03Chuck Nice?

  Very hot.

• 32:04Neil deGrasse Tyson?

  And it will melt almost anything you would eat. Like cheese would just be melted.

• 32:09Chuck Nice?

  Right.

• 32:09Neil deGrasse Tyson?

  And so if the moon were made of cheese, half of it would just melt off the face.

• 32:12Chuck Nice?

  Right.

• 32:13Neil deGrasse Tyson?

  Right? So, but now the moon is turning, and it takes a month to turn, turns out. And because it matches the time it takes to go around the earth. So on the side where the sun is not shining, it, it's like, how cold, how cold does it get on the, on the dark side? The, the unlit side of the moon?

• 32:30Speaker 02

  About 250 below zero.

• 32:32Neil deGrasse Tyson?

  Yeah, below zero. So that'll freeze it right back up.

• 32:34Chuck Nice?

  Right.

• 32:35Neil deGrasse Tyson?

  Right. So, so, so if you want to live on the moon and not melt or freeze, you want to be in like a rotisserie right at the boundary of light and dark.

• 32:44Chuck Nice?

  You just want to find that line of light and dark and spin around.

• 32:47Neil deGrasse Tyson?

  Just, just rotate, just so you decide either it's baked, is shared, is, is, is exchanged intermittently beside this frozen.

• 32:55Chuck Nice?

  There you go.

• 32:55Neil deGrasse Tyson?

  And that way you stay one, one temperature.

• 32:57Chuck Nice?

  And see, that's why I ask these questions, because we still learn something after all.

• 33:01Neil deGrasse Tyson?

  After all.

• 33:02Chuck Nice?

  Okay.

• 33:03Neil deGrasse Tyson?

  We're gonna take a break. We'll come back to Cosmic Queries on the Great American Eclipse with my friend and colleague and, and Hayden associate, Joe Rao on video call.

• 33:19Neil deGrasse Tyson?

  We're back on StarTalk Cosmic Queries Edition. Special topic of Merck Great Eclipse.

• 33:26Chuck Nice?

  Merck.

• 33:27Neil deGrasse Tyson?

  Monday, August 21st, Dateline 2017. I got Chuck Nice, I got Joe Rao on video call, uh, uh, an associate of the Hayden Planetary, my go-to man for everything night sky. And in this particular case, it's day sky. So, give me another.

• 33:43Speaker 02

  Can I, can I make a, can I just make, before, before the next question, can I just make one suggestion to anyone who's watching, who's planning to see this eclipse, the first eclipse that he or she has ever seen? Um, a lot of people are gonna try to photograph this eclipse. And my suggestion to any first-timer is don't bother taking pictures. You want to drink in every single last second of the total phase of the eclipse. You don't want to fumble around with your iPhone. You don't want to, if you have a camera and looking for the aperture settings or whatever. You just want to sit and watch and enjoy this entire beautiful spectacle. Because I've told people before, Chuck and Neil, trying to photograph your very first total eclipse of the sun is like your first girlfriend.

• 34:28Speaker 02

  You're not very good at it. It's over very quickly and you just want to do it all over again. And that's, it's that kind of a thing.

• 34:36Chuck Nice?

  And, okay, since it's like your first girlfriend, do you cry when it's over? Because that was my experience.

• 34:46Neil deGrasse Tyson?

  I will add that lately, people have been using their smartphone to take video of extraordinary events that are in front of them. And so, here's something extraordinary in front of them, and they're looking at a two-inch screen of the extraordinary event.

• 35:00Chuck Nice?

  Right.

• 35:01Neil deGrasse Tyson?

  So that, in fact, the cost of keeping a video of it is having missed the event entirely.

• 35:09Chuck Nice?

  Absolutely. That's the expense of, the expense of having that video. Is that you actually missed the thing that you were there to see.

• 35:14Neil deGrasse Tyson?

  It was some event where the Pope was going by, and everybody looking at the Pope through the thing.

• 35:19Chuck Nice?

  Right. Look at the man that just, what are you doing? He's right there.

• 35:22Neil deGrasse Tyson?

  Right, right.

• 35:23Chuck Nice?

  He's right.

• 35:24Neil deGrasse Tyson?

  Yeah, so, uh, maybe you might want to commit this event to your own memory.

• 35:29Chuck Nice?

  Alright, next question. Alright, here we go. This is Heath McCalland, and Heath would like to know this, coming to us from Facebook for astronauts watching from the ISS. Will any man-made lights be visible to the naked eye in the umbria of the eclipse?

• 35:48Neil deGrasse Tyson?

  Hmm.

• 35:49Chuck Nice?

  Interesting question.

• 35:50Neil deGrasse Tyson?

  So, Joe?

• 35:52Speaker 02

  They've already, they, believe it or not, they have already done, uh, the computations, and the astronauts onboard the ISS will see the, uh, eclipse on three separate, um, rotations or three separate orbits of the Earth. They will not see a total eclipse, but they will see, in the most extreme case, something like an 80% partial eclipse. And when they look down on the Earth, what they will see will be, in essence, what looks to be like a black stain. That is projected upon the surface of the earth, be it on the ocean, or as it's passing over the United States, and that black stain, of course, is the earth's, uh, is the moon's umbra, the dark shadow that's going to create, uh, the total eclipse of the sun.

• 36:36Speaker 02

  I, I think only one time in the history of manned spaceflight, uh, I think it was Gemini 12, uh, two astronauts circling the earth back in 1966, did briefly, for a few seconds, see a total eclipse of the sun as they passed into the moon shadow. I think one of those astronauts, in fact, was Buzz Aldrin, the second man to walk on the moon. But, uh, it's, it's, it's, I guess, difficult to, you know, get the, the, uh, the space vehicle involved as it's circling the earth, getting into the shadow of, of the moon. Uh, but they will be able to see, uh, from, uh, the International Space Station, uh, what's going on down there with that black shadow moving over the earth, and up in the sky with the moon passing across the face of the sun.

• 37:18Neil deGrasse Tyson?

  So Joe, how fast is the shadow moving on earth's surface?

• 37:21Speaker 02

  Well, the moon goes around the earth, uh, at a speed of about 2,300 miles per hour. You would think that that would be the speed as it's moving across the surface of the earth, but that's not true because we here on the earth are on a turning earth. And, and so, we are moving and we are, in some cases, staying with the shadow for a period of time, especially if the shadow is passing over the equatorial regions. Uh, we could stay with it, uh, and, and help to slow the movement of the shadow across the earth down. In this particular case, the shadow, as it goes from coast to coast across the United States, will be moving roughly at an average speed of about 1600 or 1700 miles per hour. It'll be moving actually a little slower over Tennessee and Kentucky,

• 38:05Speaker 02

  and a bit faster as it's entering the United States from the Pacific coast, but still rather rapid speed. And, uh, uh, even if you had a, a, you know, one of those supersonic transport planes, you wouldn't be able to stay in it forever. You, you, the moon eventually is going to win out with that, uh, with that fast movement.

• 38:23Neil deGrasse Tyson?

  One of my favorite things to look for, particularly in eclipses where the shadow is not as big as the one that I had seen, uh, so the, the eclipse is shorter. My favorite thing is to watch the shadow approach from the horizon.

• 38:35Speaker 02

  Nice.

• 38:35Neil deGrasse Tyson?

  Moving at 1,700 miles an hour. It's this cut through the atmosphere, and it is dark in the center, yet it is twilight on each side of it. And here it comes.

• 38:47Neil deGrasse Tyson?

  And then you, no one's gonna be looking at it, cuz all gonna be looking up. But the old timers, who've seen ten a dozen eclipses, the greedy ones, we got, we know the other stuff to look at.

• 38:56Chuck Nice?

  Right.

• 38:56Neil deGrasse Tyson?

  That's the sideshow that makes up the total circus that this is.

• 39:00Chuck Nice?

  Sweet.

• 39:01Neil deGrasse Tyson?

  So what else you have?

• 39:01Chuck Nice?

  Alright, here we go. Um, uh, Jeff, so stars check. So star check, wants to know this. Does, I'm sure I butchered your name, Jeff.

• 39:11Neil deGrasse Tyson?

  This is your, if you didn't, we would not know who you were.

• 39:16Chuck Nice?

  Alright, here we go. Uh, Jeff wants to know this. Uh, does the solar eclipse give our ground-based telescopes an enhanced view of distant objects due to gravitational lensing? So are, is there any, um, enhanced view of what we're looking out past during the eclipse? And wasn't there, I mean, isn't that how we prove Einstein right about his?

• 39:36Neil deGrasse Tyson?

  You remember this, in the year 1919.

• 39:39Chuck Nice?

  Correct.

• 39:39Neil deGrasse Tyson?

  Sir Arthur Eddington led an expedition to test this three-year-old prediction that gravity would bend the path of light. Severe gravity would bend it noticeably. And they, they wanted to do it in an eclipse in 1918. But the, the First World War was, the Great War was still interfering with, um, uh, material and personnel movement. Uh, so they had to wait till 1919. And sure enough, they made the measurements. The stars whose light passed near the edge of the sun, which you wouldn't otherwise be able to see in the daytime.

• 40:11Chuck Nice?

  Right.

• 40:12Neil deGrasse Tyson?

  Uh, or, or when you're not in eclipse.

• 40:14Chuck Nice?

  Right, right.

• 40:15Neil deGrasse Tyson?

  So the positions of those stars were slightly different than when they were six months later, when you would observe them in the dark of night. Um, and that bending confirmed Einstein's general theory of relativity.

• 40:27Chuck Nice?

  Right, yeah.

• 40:28Neil deGrasse Tyson?

  So, so that's exactly how that played out.

• 40:30Chuck Nice?

  Super cool, man.

• 40:31Neil deGrasse Tyson?

  We got more?

• 40:32Chuck Nice?

  Here we go, here we go, here we go. Will there be a measurable temperature? And maybe Joe can, uh, tell us this. John Reinhold wants to know this. Will there be a measurable air temperature difference during the eclipse?

• 40:43Neil deGrasse Tyson?

  Joe?

• 40:45Speaker 02

  Yes, they most definitely will. In fact, in the middle part of the country where it will be happening at midday, or actually in the eastern half of the country, where it'll be happening at 2 or 3 o'clock in the afternoon, if there's enough of the sun covered, 80, 90% or a total, you could get a temperature drop of 3, 4, 5 degrees or more. And as the air actually begins to contract with that cooling of the atmosphere, that helps to pull in the winds from all directions. That's why sometimes when you get the midpoint of a major eclipse, a cool breeze suddenly starts to spring up. So, most definitely, maybe not so much in the western United States, where it'll be during the morning hours, and there hasn't been enough heating taking place

• 41:27Speaker 02

  yet, but most definitely in the middle part of the country and in the eastern part of the country, you will get a noticeable temperature drop around or soon after the point of mid- eclipse.

• 41:38Neil deGrasse Tyson?

  And it's not only an actual air temperature, there's also, once the sun is blocked, you're no longer getting radiant heat. Okay? You ever notice if someone walks between you and a fireplace, you feel instantly cold? Well, the air temperature's the same. The air temperature didn't all of a sudden change in that instant. It's the heat emanating from the fire. It's the photons coming from the fire, touching your skin and getting absorbed. It has nothing to do with the temperature of the air. So you blot out the sun, you not only get the cooling that Joe's talking about, you get the absence of photons that you had been basked in. This is why shade is cooler than non-shade in the summertime. It's the only reason why. It's just blocking those photons. It's just blocking this extra source of heat to you. The shade is not really cooler than being out in the

• 42:20Neil deGrasse Tyson?

  sunlight. If you're walking in and out of the shade, back and forth, the air is all mixed.

• 42:24Chuck Nice?

  I can't wait to lay by a fire with my wife. The next time, I'll be like, "Baby, that's not heat. That's my photons." You feel that, girl? Feel my photons, girl?

• 42:36Neil deGrasse Tyson?

  I've got time for one more.

• 42:37Speaker 02

  All right, here we go. This is actually important. James Cultus, asking a very important question here. "Hey Neil, are you going to watch the eclipse in person?" Which we know you are. "If so, and Joe can chime in on this too, please tell me what gear you will use. Should we watch through binoculars, telescopes, glasses, wine?"

• 43:01Speaker 02

  Just hold your glass to wind up.

• 43:04Neil deGrasse Tyson?

  Joe, we didn't spend any time on this. Give it, give us some concluding comments on what's the best way to view the eclipse.

• 43:10Speaker 02

  Oh, well, the best way I, you know, everybody has been scrounging around for eclipse glasses. And in fact, believe it or not, now they're a knockoff eclipse glasses. These glasses are made either of Mylar or a special plastic called polymer, and they have been tested. Uh, they have been certified, but there are some places that haven't been certified. They could have a scratch in them. You have to be very, very careful with that. A lot of these knockoffs have suddenly appeared over the last couple, three weeks. You don't have to look directly at the sun, however. If you do, you, you could also use welder's glass. Number thirteen and number fourteen welder's glass. You can get that at any hardware store or welding supply store. It'll turn the sun green when you look through it, but it will be enough so that you'll be able to see it safely.

• 43:53Speaker 02

  It blocks out both the visible infrared and ultraviolet radiations. But if you don't even want to look at the sun directly, you can just find a shade tree. I think this is most delightful. The light going through the spaces in between the leaves project or dapple the ground with hundreds of these images of the sun on the ground, and if there's a light breeze, they almost seem like they're twinkling. It's, it's the same methodology as when you're doing a pinhole image of the sun. You let the sun's light go through a pinhole, and then you hold a card or a, a piece of paper about two or three feet away from the pinhole, and you can see the image projected on that screen using the pinhole image. The trees do it for you naturally. And by the way, you could also use a mirror, believe it or not.

• 44:36Speaker 02

  If you have like, let's say a compact mirror or a small mirror, just punch a hole in a piece of construction paper. Put it over the mirror and then turn the mirror to the sun. You could project that image onto, let's say, the side of a house, and it will project the exact same image that's happening up in the sky. Another very safe way of looking at it. You don't have to worry about blinding yourself. You just look at that projected image using the mirror. So there are a number of safe ways. Don't look at it with sunglasses. Don't look at it directly. Don't use smoke glass. That just transmits the ultraviolet infrared uh, uh, in, uh, uh, radiation into your eye. And since your eyes don't, can't sense pain. Uh, your eyes, if you're looking through a piece of smoke glass, for example, are being fried

• 45:20Speaker 02

  without your being aware of it. You'll learn about it later when you see a hole and you can't. See anything anymore in that particular spot where you're looking at the sun.

• 45:29Neil deGrasse Tyson?

  So now, and during totality?

• 45:30Speaker 02

  You can look directly at the sun during the total phase only of the eclipse. That's the time to take your eyewear off, put down the projected cards, and look directly up at the sun. That will give you a spectacular view, but make sure that when the sun begins to emerge, that you put those glasses back on again, because again, even that slight little sliver of sunlight is still dangerous to look at.

• 45:52Neil deGrasse Tyson?

  A quick couple of tidbits, just to end the show with.

• 45:55Speaker 02

  Go ahead.

• 45:56Neil deGrasse Tyson?

  The two parts of the shadow, the darkest part is the umbra. That's totality, and the surrounding area is the penumbra, which is where part of the sun is covered. Umbra is the same Latin root that we use for umbrella.

• 46:10Speaker 02

  Nice.

• 46:11Neil deGrasse Tyson?

  Umbrella.

• 46:11Speaker 02

  Umbrella.

• 46:12Neil deGrasse Tyson?

  And umbra are related words.

• 46:14Speaker 02

  Yes.

• 46:14Neil deGrasse Tyson?

  That's cool.

• 46:15Speaker 02

  That is cool.

• 46:16Neil deGrasse Tyson?

  Not only that, as the sun gets more and more eclipsed, and there's a thinner and thinner sliver, the source of light becomes more point-like. And we take for granted what our shadows look like on the street. They all have fuzzy edges. You don't think about it, because that's just your shadow. As the sun gets narrower and narrower, it will cast a shadow the way stage lights will cast a shadow with very sharp edges. And all of a sudden, this is what Joe alluded to earlier, there's an eerie effect that takes place around you. Shadows look different. They're more precise. They're sharp. They're eerie. You're in an otherworldly landscape during these last few moments of the eclipse.

• 47:00Speaker 02

  Man, that sounds like an LSD trip.

• 47:01Neil deGrasse Tyson?

  Then, that last little bit of the sun, Joe, what do we call that? That last little bit?

• 47:07Speaker 02

  We call it the diamond ring.

• 47:09Neil deGrasse Tyson?

  The diamond ring.

• 47:10Speaker 02

  Or Bailey's beads. Bailey's beads? I like diamond rings.

• 47:15Neil deGrasse Tyson?

  Yeah, there's ointment for that.

• 47:20Neil deGrasse Tyson?

  So the diamond ring effect is that last little bit, it's bright on top and you can still see the outline of the moon, so it looks like a wedding ring.

• 47:29Speaker 02

  Right.

• 47:29Neil deGrasse Tyson?

  Yeah, yeah. An engagement ring.

• 47:31Speaker 02

  An engagement ring, yeah, that's cool.

• 47:32Neil deGrasse Tyson?

  Joe, we gotta end it there. Thanks for videoing in to StarTalk.

• 47:37Speaker 02

  Thank you for inviting me, and good luck to all who are gonna be at the eclipse on Monday, the 21st.

• 47:42Neil deGrasse Tyson?

  Joe, it doesn't take luck, it takes knowledge.

• 47:48Neil deGrasse Tyson?

  Anyway, Chuck. Hey. Love you, man. I love you too, man. All right. You've been watching, possibly listening, to StarTalk. And we've been recording this live at the Mashable World Headquarters. The Mashable Universe Headquarters in New York City. I've been your host, Neil deGrasse Tyson, Chuck Nice, Joe Rao on video. I've been your personal astrophysicist. And until next time, I bid you to keep looking.