StarTalk Radio - Eclipses, Cosmic Cataclysms, and More with Janna Levin

Episode Date: April 5, 2024

What can we learn from eclipses? Janna Levin joined by comedian Matt Kirshen and professor of astronomy and astrophysics at Columbia University, Joe Patterson, discuss the 2017 eclipse, binary star systems, super novae and more. What is an eclipse on Jupiter like?NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here:https://startalkmedia.com/show/eclipses-cosmic-cataclysms-janna-levin/ Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

Coming up is a show recorded on the day of the last total solar eclipse to cross the United States back in 2017. It's got my friend and colleague, Jan Eleven, who will carry you through what to look for, what to expect, and give you little tidbits about the sun as well. Coming up. Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now. Welcome to StarTalk All-Stars. I'm your All-Stars host, Jana Levin.

I'm also a professor of physics and astronomy at Barnard College of Columbia University and director of sciences here at Pioneer Works, where we're hosting this show. Very excited to be here. We've never done a show from here before, so this is awesome. I want to introduce my guest, co-host, Matt Kirshen, comedian and host of Probably Science podcast. Hi, Matt. Hey, Jana.

Welcome. How was your nap? It's been good. I came in on the red eye. Yeah, you had a little nap. Had a little sleep on. You've got some very good couches here at Pioneer Works. I'm feeling great.

Okay, excellent. And I'm very excited to welcome for the first time on the show our expert scientist, Professor Joe Patterson. And I have to say about Joe, he is many things. He's a professor of astronomy at Columbia University. He is also, I think you said, director of the Center for Backyard Astrophysics. Super cool. Citizen science, well before its time, well before citizen science was even a phrase, right? Cool. And also my first astronomy professor.

I remember very fondly. And she got pretty good grades. I got me. I would climb into the back of the classroom in pupin at Columbia with those stacked levels. You know, they're so steep with like my big cup of coffee. And I'd be like, but you are such an amazing professor, Joe. Really, just the greatest. So thank you for that. A little small applause for Joe. Welcome to our show. I'm also wearing my eclipse glasses

because this is the day of the August 21st, 2017 eclipse. You know what I loved in the 1918 newspapers when they talked about the eclipse that ran from the Pacific to the Atlantic? They said, forecasted the next eclipse of its kind in 2017. Isn't that kind of crazy that the people at the time would have been reading those papers? Yeah, well, I think eclipses were probably very exciting then. Actually, the next year there was an eclipse in the Indian Ocean, which is one I know that you know quite a bit about

because it's the one that verified Einstein's prediction. 1919. 1919. Yeah, when Eddington went off the coast of Africa. That's right. And it was also the significance of 1919 was magnified because, of course, the armistice had just been signed and it was a British team verifying a theory by a German scientist

which overthrew Newton's theory of gravity. And this is six months after World War I, when the countries were killing each other. And they're like, it's like out of the shadow of the war, into the shadow of the moon. Can you tell me what it was that they verified? This is something that Einstein made a prediction, general relativity, and then something happened during the eclipse that they could use to test one of these predictions.

What was it? Yeah. Joe can tell the story. Okay. Yeah. One of the predictions, light, of course, carries energy. And Einstein said that energy and mass are equivalent. It's a famous equation, E equals MC squared. and Einstein said that energy and mass are equivalent.

It's a famous equation, E equals mc squared. So if it carries energy, it carries mass. If it has mass, then it means gravity must affect it, must affect light. Never really been thought about before, but in Einstein's theory, a strong source of gravity should bend light. But there were no sort of strong sources of gravity around at the time, except people thought, well, during a solar eclipse, if you look at the position of a star, take a photograph of the sun in a solar eclipse,

you can see some stars around the edges because it's so dark out, and look at the positions of those stars and if the light has been bent those positions will have shifted from their normal positions so you you'd know where the star should be just because of where it has been in its trajectory space astronomy and then and then the sun is suddenly in the way and that light from the star would have slightly curved around it right so if there hadn't been an eclipse you'd be blinded by the light of the sun is suddenly in the way, and that light from the star would have slightly curved around it. Right. So if there hadn't been an eclipse, you'd be blinded by the light of the sun. So, like, in this case, I think they looked at the Hades cluster. And so it was directly behind the sun, and usually you'd be completely blinded by the light of the sun.

And what would you know, right? But with the total eclipse, the sun goes dark, and you have this opportunity to see this thin vapor of light, right? Just come around the bend when you know it's behind the sun. Right, so you're just able to see a tiny bit of this star that you should never be able to see because there should be an entire star between them. Yeah, but I love what you were saying in the opening, which is that this was really a tremendous moment for people to crawl out of this hideous patriotism, right, nationalism,

and instead to feel like citizens of one place, you know, one planet. I mean, to be fair, Einstein later left Germany and went to America, and then that was part of the ally team. So we got him back. So I'm still claiming Einstein as part of team allies. Well, you know, amazingly, Eddington is really the one who catapulted Einstein's fame in the English-speaking world. I mean, that was really the event, right? And then Einstein becomes incredibly famous.

It's on the covers of all the newspapers. And that's the cleverest experiment I can think of from an eclipse. But there are some really amazing experiments now, which are probably deeply clever, but just somehow don't have the singular historic placement. So what do people do now scientifically from an eclipse? What is scientifically valuable? I mean, we had this eclipse today. It was incredible. You had 4,000 people out of Columbia. It was amazing. How was your view, by the way? Did you get clouds? You know, it was sort of partly cloudy. But gosh, you know, there was just very little,

everyone was very elated at this event. It hadn't happened in such a long time. And people, for reasons that amaze me and delight me, people react with enormous glee at this sort of scientific spectacle in the sky. Yeah. So you didn't expect 4,000 people? Yeah. What did you expect? I expected maybe about 250 people.

Okay. I started to worry about like 700 people coming or something like that, but I did not expect thousands. That was really fantastic. And it was exciting, right? Did people, they got into it, even when the clouds were there, and then it would come back?

Yeah, well, people, they'd come with their friends, and they'd look for glasses. We brought 500 glasses. Yeah, I stole some of your glasses. You had 500 minus about 70. Okay, well, there you go. You gave them to me personally. That's true.

I remember it now. A lot has happened since yesterday. But, yeah, so they disappeared pretty fast. But people shared them around. I mean, you don't sit there looking at it for four hours. No, absolutely not. The only one that did was me. It's good to share them.

It was me because people kept needing help with the telescope. And, frankly, I'm still getting some after images in my eyes. Oh, no. Oh, no. That's not good. I think I'll be OK in a few hours. But yeah. You were using like the finder of the telescope without a filter?

No, the technique is we would just use your hand in the finder. Oh, OK. And then you would find it. Right. So the finder casts an image of the sun on your hand. Yeah. And that's how you know you of the sun on your hand. Yeah. And that's how you know you're pointing in the right direction. That's how you know you're pointing in the right direction.

And, of course, when the kids come up, some of the littlest of children are the most violent treaters of telescopes. Some kind of mathematical law there. And so they would sort of bash the telescope, and you'd have to reorient it there. Yeah. But it was... But that's great to have that many people getting excited at a young age.

Oh, absolutely. Absolutely, yeah. So I asked... Oh, sorry, Matt. No, no, go for it. No, I was just going to say, I asked you originally, what are the scientific experiments that people do now from an eclipse? So we did it for fun and elation and excitement.

Yeah, everyone was happy. It was my first time seeing an eclipse in America as well, which is cool like normally as you know i'm normally like in a jungle somewhere tricking people into making them my god uh or me their god rather uh i mean that's the best use of any eclipse scientifically to trick yeah and and has it worked in the past yeah i'm now the god of quite a few different cultures and it also a little tip you don't have to wait for a solar eclipse lunar eclipse worked perfectly well in terms of yeah intimidating yeah columbus columbus found that out in 1523 and one of the many good things he did so wait what was 1523 well he uh no it was it was an earlier one it was 1504 it's 1504 he knew there was going to be a

lunar eclipse on a particular night and you know he was uh you know set up an assembly line uh tell the local people to supply him with certain amount of sugar and gold and uh whatnot and then they would get those cardboard glasses no no no he would have loved to have them. But, you know, he basically said, look, you know, your shipments have been a little sparse lately. If you don't pick up the pace, I'm going to basically blot out the moon tomorrow night. I don't think so, buddy. I don't think. And then he did. Oh, my God.

That's a good trick. And so he got a lot of cooperation after that. Wow. What most people don't know is there wasn't actually an eclipse planned. He really did have that power. And you've learned to harness it. Okay, I'm going to ask Joe for the third time. The third time I'm going to get Joe to answer this question.

Fun and games aside, what is the real science that real scientists are doing? Yes. Right now, the solar eclipse is primarily a place where people go crazy, lives are changed. My life was changed with my first eclipse. But scientific experiments are being done primarily to study the corona. The corona is never studied as sensitively

as when the photosphere of the sun is blotted out. And while you can do it a little bit from the tops of mountains where you get above the dust layer and then you could kind of study the outer layer of corona because some of the bright blue sky is muted up there uh the lower corona you can never see but during an eclipse you can because when the moon fits over the sun like a glove and you get the entire photosphere blocked yeah from that then you can because when the moon fits over the sun like a glove and you get the entire photosphere blocked yeah from the then you can look at the lower corona and you can see well the structure in the lower corona one of the things that we'd like to know for example is um what supports the

corona um most people have seen pictures of the corona. Most of them are actually taken during eclipses, as a matter of fact. And so you have this big thing in the sky, big luminous thing in the sky, and you'd think that it ought to collapse down on the sun. You know, the gravity of the sun is pretty intense, so why doesn't that gas collapse back on? So it's like some kind of plasma, magnetic plasma, magnetized plasma. Yeah, it's very hot gas.

And it's like frothing. It's always like churning and frothing. It's something I heard just last week because of all the articles about the eclipse. I didn't realize that the corona is hotter than the surface of the sun. By a lot. The hottest parts are 100 million K. Kelvin. Kelvin.

People speak only Fahrenheit in our audience. I'm not going to attest that nobody speaks Celsius or Kelvin. Kelvin. People speak only Fahrenheit in our audience. So I'm not going to attest that nobody speaks Celsius or Kelvin, but I'm going to say it's like tens of millions of Fahrenheit. Is that about right? Okay, well, double it approximately. I don't know. Anyway, about 10 million Kelvin for the center of the sun, but about 100 million for the outside.

So it is. It's hotter. Parts of it are hotter. Which is crazy because the center of the sun is where about 100 million for the outside. So it is. It's hotter. Parts of it are hotter. Which is crazy because the center of the sun is where all the nuclear reactions happen. So it's hot enough in the center of the sun to have a nuclear bomb. Nuclear fusion. And then the atmosphere gets down to like 10,000

Fahrenheit or something like that. The atmosphere is about 10,000 Fahrenheit. Yeah. And then it goes way up at the corona. So nobody knows why. Maybe they will after this eclipse that's a possibility i mean there's some kind of way to generate energy into into the atmosphere uh and we have of course we have an atmosphere which uh also rises in temperature slightly when you go farther up at first i did not know that yeah when you go up to about a hundred thousand

feet it's dropping dropping dropping, dropping, dropping. Then above 100,000 feet, it starts to climb a little bit. Interesting. Yeah. Is that because of sunlight hitting? Well, yeah. It's because some of the sunlight actually gets absorbed up there. Right.

And it gets absorbed directly. And there's not much matter up there. So you absorb the sunlight. There's not much matter. And so it's fairly hot. Now even though it's hot, if you went there, and it went outside, you'd die immediately, but I don't know how you would die exactly, but... Say you had some kind of support system.

But if you didn't die that way, there'd be an alternative. Yeah, if you had a support system, you'd find it cold because of course the density is so low that the amount of collisions on your body... So these particles have more energy than they would do a little bit lower down, but they're hitting you less frequently. Very less frequently. Right, exactly, rarely. So is the corona responsible for the solar winds?

The corona itself, we don't know the answer to that. So like Aurora Borealis and the Northern Lights are coming from solar winds striking our own magnetic field. And so it's unknown if that originates from the corona. Well, it originates in the same place that the corona originates. But the present, I think, most common theory is that they come out of holes in the corona. The corona has holes in it. And so basically because some time-lapse movies have been taken of basically streams of material coming out through these holes in the corona.

And they go out to, well, they go out to the whole solar system. Amazing. And they eventually cause the northern lights and the southern lights. And they get to Jupiter. And eventually they leave the solar system. So you were mentioning your first solar eclipse changed your life. What year was that? It was 1970.

But you had seen an eclipse before, just not a total. Is that right? Well, that's right. As a child growing up in Japan, I had seen about a 90% eclipse. You didn't stare at it, did you? I don't know what I did. Somebody gave me a piece of glass or something, and I can't remember anything about it.

I just do remember when 1970 rolled around, I thought, well, you know, I see a 90%. You know, should I go down to Virginia to see a total? I'll see 100%. What could the 10% be? And I just graduated from college, and one of the math teachers there said, it doesn't work that way.

He was a math teacher. Had to accept it. Had to work that way, right? So we go down there, and so on March 7, 1970, it was totally clear. It was an experience that changed my life. It was, I think for many people who see a total eclipse, it's sort of a marker in their life, you know, like your birth, your death, your marriage perhaps.

Wait, the solar eclipse comes after death? Are you doing this chronologically, Joe? I'm very confused. Well, this is science. We don't know everything. Wait, birth, death, then marriage? Well, okay. These things can be rearranged in various orders, depending on your metaphysics or your lifestyle. But anyway, so I became an eclipse junkie then.

I saw the next eclipse. Have you chased many? I've only chased four. I guess I count this one because I live in New York City. You opted not to go. I opted not to go. There are certain things you only need to do once, actually. Is death one of them?

I would be a little afraid. I would be a little afraid that if I went to another total eclipse. It would alter you. It would, no, no, no. It would just be some kind of letdown. It would just be, I did it before. It's the same. You know, I can't, it's not, I don't know.

Because I never saw, the second one I saw was very spoiled by clouds. Right. The third one, the same. Right. So, what happens, if you do have one

that's even better than the first one, then you end up, then you're stuck. Then you have to spend your entire life saving up to the next eclipse. Oh, yeah,

it's even worse. That's true. And you're like, all right. It turns out to be better than the first one. And you're like, oh, okay,

I guess it just gets better every time. Now I have to, that's my life now. I have to put teaching on and research on hold. That's the technical definition of addiction. Yeah. But there are people who chase eclipses all the time.

Some people have seen 50. That's insane. There's about one a year somewhere on the Earth. One partial or one total? No, there's about one total eclipse a year somewhere on the Earth's surface. About one. Do you want to tell us why it's so rare?

Why don't we have it monthly? Why isn't it every time there's a new moon, when the sun is basically behind the moon to some extent, right? So it goes dark. Why don't we have a total eclipse every month? Yeah. So if the moon orbited in exactly the same plane as the sun,

then indeed, every time there was a new moon, it would just fit right over the sun like a glove, have an eclipse. You have to turn the lights on if you're driving. Yep. And then after a while people would think of it as i don't know a nuisance perhaps they'd be like oh this again be something they just list next to the weather right the phase of the moon there was only a full moon once every

hundred years we'd be like there'd be parties to go see the full moon we'd be like howling but it would it would just it was it in the paper, just like sunrise, sunset, eclipse. Hasn't been a full moon since 1918. Yep. Yeah. So that's what it would be if it were in the same plane. Right. But the moon's orbit is tilted by five degrees.

It's five degrees, okay? So the moon is half a degree in diameter. So that's a lot. So it misses. Yeah. So it misses like nine- nine tenths of the time and so each time it goes around and crosses the orbit of the earth it's it's not necessarily new moon yeah well there's a technical definition of the moon when it's sort of exactly you know

above or below the sun or at the sun okay So that's the technical definition of a new moon. So we do say there is a new moon. But it's not exactly the newest of all new moons. I'm Jasmine Wilson and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson. Am I right in thinking it's just coincidence that the moon fits exactly over the sun?

Or is there any greater reason why it's exactly the right size for an eclipse i i guess i guess it can only be coincidence yeah i can't think of any uh reason that um that you know one half a degree which is the angle that the sun both the sun and the moon have uh you know i i guess the only thing i think of is if it were something smaller, if the moon were smaller than it is or bigger than it is, it may not have been, the orbit might not have been stable. Right. Every orbit has to hang around for four and a half billion years because we're now talking, we're having this conversation, four and a half billion years after all these events

took place that arranged the solar system. Right. So everything that you arranged has to be stable. And there are certain things that are not very stable. Like if the moon is farther away, a lot farther away than its present distance, then basically Jupiter, Saturn could occasionally sort of tug it out and we might lose our moon. Oh, right. Yeah. So the moon is 400 times smaller than the sun.

Is that right? 400, yeah. 400. So it also happens to be 400 times closer. Yeah. And that like my thumb is a lot smaller than the moon, but I can keep it really close to my eye and I can cause a total eclipse of the sun this way, right?

You absolutely can. It's very instructive to do it too, actually. You get a feeling on a clear day. On a cloudy day, it's not interesting at all. But on a clear day, you can just do that and it's a measure of exactly how clear the day is because sometimes you can see the blue going all the way to the edge of your thumb. That's a really, really clear day. And that's how solar astronomers,

when they pick their observatory, that's how they're going. They're all on mountaintops. And there's a lot of people sticking their thumbs in the air. So the big difference with the moon eclipsing the sun and a solar eclipse in my thumb is that I cast a much tinier shadow

and the entire U.S. is not excited about the shadow cast by my thumb. Is that fair to say? So the moon casts a 70 mile wide shadow that we can all share. But in principle, I could do this every day and be like, woo, it's an eclipse of the sun. But this is an interesting thing because what it also means is that the angular size you know it just so happens that humans have an arm this is and a thumb an arm that is long enough and a thumb that is wide enough to replicate that particular half a degree number i certainly do she does sure her proportions are fairly normal skip the the fairly, brother. Let's not get into this in a podcast.

So would it be possible, if you wanted to do some of the experiments that you normally only have to wait until an eclipse to do, to send up into space a telescope and a blocker? There is one. Okay. Yeah, there is an experiment where they fake an eclipse all the time with this thing. So they have one

telescope in space pointing at the sun. And it has a, do you remember what it's called? I can't remember what it's called. Sorry, apologies to the PI on that particular experiment. But I mean, there's something that is supposed to be spectacular about the moon doing it. And I'm not sure exactly what it is, but in terms of

coronal physics and studying it. But I'm not sure exactly what it is, but in terms of coronal physics and studying it. But I have another question about coincidences. So I've heard a theory, and I know it's just a theory that it's not that well substantiated, that early in the Earth's formation, an asteroid slammed into the planet, a big one, and sloughed off the moon, basically,

out of Earth's stuff and created the moon. The moon settled into a spheroidal shape, the Earth settles into a spheroidal shape, and it also tilts the Earth. So it creates not only our lunar system, but the seasons. Have you heard this theory? Yes. What's your feeling on it? Well, you know, I haven't read the papers on it. I know when I first heard about it, I thought it was a stretch, to say the least. I didn't really know why you need to have

a special mechanism to make the moon because, after all, there are moons all over the solar system. Are there going to be special mechanisms for all those other things? On the other hand, our moon's a little different because the Earth-moon system is a kind of sister-brother relationship there. They're almost two planets.

They're almost the same compared to the ratio. Jupiter has just a bunch of tiny things going around it. Yeah, so Jupiter has, what, dozens of moons. Yeah, it has, I think, at least 28 named moons, actually. Yeah, and they're much, much, much smaller than Jupiter because Jupiter is, like, huge. But the moon's, what, a quarter the size of the Earth. That's not that much smaller.

That's, like, in the zone. Like, I'm a quarter your size. Yeah, and in fact, you know, interstellar travelers, if they're zooming in on the solar system, their eye would be caught by the Earth-moon system. And, you know, none of us knows exactly what caused life on Earth. But anyway, I think they could actually consider it a good habitat for life, actually, because of the moon. So this tilt that the Earth has is also part of the way the eclipses work,

and the complexity of it, and where they land on the Earth. And this tilt is also really important for the seasons. Do you think the tilt of the earth is important for emergence of life on the earth? I mean, could it be, so instead of the earth facing straight up when it orbits the sun, it actually points towards the sun. Yeah. And it's the reason why it's summer in the Northern Hemisphere and winter in Australia and vice versa at the same time.

Yeah, well, if you had a tilt, if you had no tilt, or if you had like a 90-degree tilt, like Uranus has a 90-degree tilt. Is it straight up and down? It's 88.5 degrees or something like that. Is it like the only one of the planets? It's the only one that's really close to 90. So if it was 90, then what would happen is the equatorial regions would be hot all the time. Right. And the polar regions would be cold all the time.

Extremely cold all the time. Although the sun would always be on. So no seasons. There would be no seasons. I know they might call them seasons, but you'd have to travel to get to the, you know. Right. And so that can't be good for life because life generally, I don't know if life needs changes, it needs really seasons, but it does sort of need the hottest of temperatures on Earth and the coldest of temperatures on Earth don't seem to be very favorable for life, but not necessarily primitive life. Primitive life might like heat more. Do you think that we're going to discover other primitive life in the solar system?

Well, I doubt it. I can't think of where it would be exactly. You doubt it? Not on the moons? Other moons? Like you were saying of Saturn, Jupiter? It's a lot of moons. And they're Earth-sized, some of them. Yeah, no, I'm not suggesting they should all be... Habitable? No, inhabitable. Okay. I'm not suggesting that the prospects are gloomy, but they're not as optimistic. We can't be as optimistic as, say, 100 years ago.

I don't know if you remember there was a famous... 100 years ago, I don't remember that well. I have like a vague memory. Oh, 100 years ago, it was great. What about you, Matt? Were you drinking a lot back then? Yes. Well, let me tell you about it. I have been around 100 memory. Oh, 100 years ago, it was great. What about you, Matt? Were you drinking a lot back then? Yes. Well, let me tell you about it.

I have been around 100 years, but close. Okay? So back in the day, everybody knows about the Charles Lindbergh, you know, the solo trip across the Atlantic, and he did it for a cash prize of whatever it was, $50,000, which was a lot of money at the time. Well, there was a Frenchman at the time who put out a cash prize to anybody who would discover intelligent life outside the Earth.

And various people, but there was a provision is you have to find the intelligent life from some other civilization with the exception of Mars because he thought it would be too easy. Too easy. Too easy to find intelligent life on Mars. I'm not going to part with my 100,000 francs. Just to bring it back to eclipses, can't you see eclipses from Mars, but with different bodies?

I think, didn't the rover see? Well, they have some very small moons on Mars, Phobos and Deimos. They orbit really fast. Do they cast shadows on Mars? I think the answer is no. I think they're too inclined or something. Oh, they're too small. Yeah.

Okay. Now, the real adventure on eclipses is Jupiter. Yeah. Because those moons are moderately big and they're close in. Because those moons are moderately big and they're close in. So on any one night, people with sort of a small telescope, portable telescope, you can train it on Jupiter and your chances of seeing a little dark spot move on Jupiter are moderately good. They're like 10 or 20% on a given night.

So if seven nights, you'll see several of them. Wow. And that's just one of Jupiter's many moons Just eclipsing a bit of Jupiter. Yeah, it's the four big moons that do it Yeah, and one of them it races around really fast And so it produces a lot of you can actually if you follow with a telescope with a lot of patients astronomers are famous for Then you can actually from hour to hour you can see it move

on the planet so apparently though it's very hard to get solar glasses there yeah yeah really hard and a good place like worse than getting them in new york city actually what happens if you like jupiter's a gas giant right does it have any kind of solid rock or is it just gas is it collected would you just sink into jupiter yes you would jupiter the surface of jupiter is uh uh if you if you tried to you know land on and what would happen is your spacecraft would just kind of keep falling i'll keep going until you got to a place where your density was about equal to the density of the local surroundings and that's just the floating point that's just yeah that would be the floating point

and you would just sort of float there. Like the Dead Sea. Yeah, or like... It would be like the Dead Sea. I'm just thinking about when I went scuba diving back and you just... A lot of scuba diving

is equalizing your density until you stay at a specific height. Is that right? Or specific depth, I guess, is the correct term, but... Yeah. Yeah, and you just... You're not meant to swim up or down.

You just increase or decrease the amount of air in your jacket and you just... You're well prepared for a trip to just increase or decrease the amount of air in your jacket. And you just... You're well prepared for a trip to Jupiter. There you go. We're sending you. Yeah, so I think with my basic open water certification from 15 years ago,

I'm more than qualified to be the first human on Jupiter. Agreed. Qualifications mean nothing anymore. Yeah. I think the most important thing nowadays is just believing you can do it yeah you just just express your opinion on the web uh yeah but i was gonna every opinion is equally valid janna it's true in the comment section on amazon so joe you said something which i think is really interesting about your work which is you said astronomers are known for their patience. And some of your research is based on things exploding. Things exploding, cannibalizing,

you know, the kind of stuff that's really fun to do in the lab, like blow things up, smash them together. But you don't do it in the lab. You kind of wait patiently for nature to do these things. So tell me about one of, like, let's pick up cataclysmic variables here. Can you tell us what those are? Yeah, well, these are very close binary stars. In other words, two distinct stars which are orbiting around each other

typically every few hours. Okay, so in other words, a year in that binary would be, say, two hours. So these are immense things moving incredibly quickly. That's right. One of them is a kind of a fairly normal star, but a very low-mass star, like one-fifth of a solar mass. And the other one is around one solar mass, but it's tiny. It's just the size of the Earth.

So is it a dead star? It's a dead star. It's already had its long life. It's a dead star. This one is, this particular one is called the white dwarf. And it's got the size of the earth, the mass of the sun. So the density is tremendous. And,

So did it, did it have a supernova event or did it blow up? Did it, like it had a long life as a star. It had a long life. The sun,

the sun will become one of these. Oh, so it just sort of, it just sort of distends. Yeah, the sun, the sun will,

you know, slough off its outer layers. Vaporizing. And its inner part, off its outer layers. Vaporizing. And its inner part, because its outer layers will be responding to the inner layers that get very hot in the later stages of life. And so it kind of drives off the outer layers. What's left is the inner layer, which is a little bit, in our case, it'll be about half a solar mass. Half the mass will be expelled, the other half will be there. So then it'll just sort of quietly, and then it just gets really dense.

It tries to collapse. It tries to collapse, but then what happens is that the electrons kind of crystallize, actually. They sort of form a lattice. So a lot, I mean, we're surrounded by things that have crystallized, you know, rocks. And they become hard and resistant to compression. Absolutely. A white dwarf would be quite a bit harder than than the hardest diamond and um anyway so there are these things they're going around uh each

other and uh what happens is the gravity from the white dwarf is so strong rips off matter from the other star falls down onto the white dwarf and the that matter is hydrogen. It builds up. Well, hydrogen, as we have known since about 1950, hydrogen will explode. If you put enough hydrogen at a high enough temperature, it explodes. Like a nuclear weapon. It's exactly like a thermonuclear weapon, only it is all over the surface of the star, all over the surface. If it were at the center, it would blow the star up. Okay.

But there is no hydrogen at the center. Okay. The reason is the gravity is so strong in the star that the center is iron, and then out beyond that is magnesium, silicon, and then carbon. Great natural resources. All of these, you can't get to them. You can't get to it absolutely and it's all crystallized and you have that hydrogen so the hydrogen blows up about every

in the case of the star that fascinates me the most about every 30 years it happens oh really so it's constantly cannibalizing its companion constantly cannibalizing but only every 30 years does it like hit criticality every 30 years it hits criticality. It's not like clockwork. Sometimes it's 20, sometimes it's 40. But about every 30 years it's happened six times in the last 140 years. Wow. And the recent one was just a few years ago. And then what happens there is it expels all the gas around it.

It expels all the gas that lay on the surface, all the hydrogen gas that didn't get burned. And it also ablates the companion. So it just blows it away. Yeah, it kind of blows away the outer parts of the companion. It's just a shell. So I'm just imagining like this hairless, sad creature. No, it's actually really good for the other star's complexion. You guys have a very positive look

on these things we call it a mutual suicide pact because what happens is because the secondary

the only reason this is happening is the secondary is feeding it's feeding the white dwarf and then the white dwarf

is thanking it by basically sort of blowing it apart so it's I mean this is how you repay me's, I mean, this is how you repay me. Just a metaphor for life. This is how you repay me. Yeah.

After all I've given to you. But it just keeps going because they don't learn. I'm Jana Levin. I'm here with my co-host, Matt Kirshen, comedian and co-host of Probably Science. Welcome, Matt. Thanks, Jana. Thanks for coming all this way. I've been on your show a bunch.

You have. We have to do it again. You have. You're our go-to astrophysicist. We haven't done an eclipse show. We'll have to do that. We'll do it again. Anytime there's any kind of black hole story or anything like that, we're like, ah, we're stuck.

Jana, help. You guys have called me like in the middle of the night. Seriously. I've been lying on the couch and Skyped with you guys, and it's been like good material. Well, thanks. Yeah. We've got a three-hour time difference as well. It's not like we're podcasting at midnight.

And we're also here with our expert scientist, Professor Joe Patterson, Professor of Astronomy at Columbia University, and also the director, right, of the Center for Backyard Astrophysics. I love that. What do you guys do for Backyard Astrophysics? Well, we're a collection of about 100 people scattered around the world, mostly amateur astronomers. There's a few professionals sprinkled in there, but mostly amateur astronomers with sophisticated telescopes in their backyards.

And they're people who, you know, they started out in astronomy and looking at the moon and looking at the moons of Jupiter. Is that how you started out? Absolutely. That's how I started out. And then after a while, they thought, well, you know, maybe I could do science with the telescope. Yeah, yeah. Is that what you thought? I never thought that myself, no. And they look around, and I've been, we've been running this organization now for 35 years, actually.

So I'm pretty well known in the amateur astronomy community. They write me letters. They say, well, you know, here's my setup. Can I contribute to your research? And I write back to them. I write lots of letters every day. Wow. And in some cases, it's, you know, like a small child in Uzbekistan or something.

It's amazing. So that's, I don't get too much from that. But the, but interestingly enough, we actually got a very good station. There was an Air Force intelligence officer stationed in Uzbekistan who said, can I contribute to your research? Well, it turns out our research needs global coverage because we follow star, follow the brightness of stars all the 24-hour period. So we need stations all around

the Earth. Uzbekistan was a good place. And he was a great, great observer and he would send us data back on the brightness of stars. He was sort of spying on Al-Qaeda by day and stars by night. Don't tell us anymore about this guy. I just want him to live through the next StarTalk episode.

Okay. But you know what I love of the many things I love about this story is it combats the notion that science is elitist because it really is a subject of just almost childlike curiosity, right, relating to the natural world. That's really what it is. It's got to be the least elitist subject imaginable. And yet we have this reputation, I think, of being an elitist field.

Do you think that that's true, that we have that reputation? Well, we do to some extent. I have to say it's greatly mitigated by the great successes at popularizing astronomy, of which you are, you know, a very prominent example, of course. Thank you. And as this program is, as a matter of fact. And Neil. And absolutely, absolutely.

Neil is, you know, tremendous energy and tremendous commitment to everybody. The last time I went, Neil and I are both big baseball fans. I went to a game with Yankee Stadium. And, of course, everybody recognizes Neil and people come up to him. Yeah, it's crazy. And they say, I remember this one guy in particular said, they don't know how to ask a question about astronomy when the great Neil Tyson is there. And, but, so they can't figure it out, but they have a friend, you know, who's an amateur

astronomer. They call up their friend and say, hey, I'm in the next row here to Neil Tyson. Do you have a question about astronomy? And they, they hire Neil the cell phone to answer him and he answers cheerfully. That's so sweet. This is really sweet. I know. He's got a really great demeanor.

Like I'm much grumpier than you. Amazing. So we were talking earlier about blowing things up. And we were talking about the cataclysmic variables. But there is another phenomenon in which well-known things blow up spectacularly, and that's the supernova event. And you've been doing some research on this recently. Yeah, well, I mostly study what happens after the supernova event, because what basically happens with a massive star is instead of just blowing off its outer layers, that has an instability in the core. So that's the really dangerous place to ignite an instability in the core of the star.

That will blow up most or all of the star. Now, isn't that good for us? And this is one of the things I really distinctly remember from your astronomy class when I first took it, how it's important for life that a star blows up. If stars never blew up, we're pretty much going to say goodbye to emergence of life in the universe. If stars never blew up, we would be mostly hydrogen and helium creatures. That would be pretty uninteresting. Pretty boring.

Very high-pitched voices. Very high-pitched voices, but helium has no chemistry at all. But if we breathed it, we'd all have high-pitched voices, but helium has no chemistry at all. But if we breathed it, we'd all have high-pitched voices. Sound like Donald Duck. But the, yeah. I thought you were going to mention a different Donald. We need the supernovae. The stars manufacture the heavy elements, but then they have to blow up. Yeah, if they didn't blow up. And so they do blow up, and that's why you get everything up to uranium. So you've been studying supernovas.

What's new? What's new in the field of stars blowing up? I mean, supernova events are amazing because they're one of the few things we can see with the naked eye. Like one day there's nothing there because the star was too faint to see. Then it blows up,

and suddenly you see this big object in the sky why can you see it after it blows up why isn't it just gone well basically a couple things happen first of all it's an enormous cloud it becomes you know very very big much bigger than any star and it's still it's still dense so they stay bright for, well, the most famous one of all, the one that made the Crab Nebula. It happened in the year 1054 on July 4th, patriotically enough. How do we know it was 1054? Is that from historical records or is that?

Yeah, historical records, Chinese and Korean records of a bright thing appearing in the constellation Taurus. And they described where it was, and we know they wrote it all down in books that we can read now. Their constellations are now understood by Chinese scholars, and we know where it was, and that is where we now see a cloud of gas that is expanding slowly outward.

So you know that, okay, a supernova happened there. And then you're like, all right, well then that's more. They must have written it. And you say both Chinese and Korean scholars wrote about it separately. They wrote about it separately. And we can see it now. There's a big, we can see it now.

It's very faint now. You need a moderate-sized telescope to see it. How long was it bright for? Well, it was visible in daylight for a month. In daylight? In daylight. That's in daylight for a month. In daylight? In daylight. That's insane. For a month.

That's like the only thing that's visible in daylight for us is the moon. Very, very, very rarely. That's right. Well, the sun, of course. Well, the sun, yeah. The sun is daylight. The sun is daylight. But it was visible in daylight, and then it was visible in the night sky for, I believe,

two years. In the night sky, meaning naked eye, because they didn't have any telescopes. And then, of course, it faded, and nobody knew about it. And then the telescope was invented, and suddenly it came back to history. And then you're like, all right, it's still there. There it is, and then it was figured out.

So we can still detect it a full millennium later. We can see it 1,000 years later, yeah. And we can still see it expanding outward. It's still expanding see it a thousand years later yeah and we can still see it expanding outward it's still expanding outward oh yeah it's still expanding outward about a thousand kilometers a second pretty hefty rate of expansion wow and uh and so it's giving all of that good stuff the carbon the heavy metals all that good stuff to its own environment that's right and then how does that lead to emergence of life? Like it blows out and then what?

You're asking me to now on StarTalk explain the origin of life? Well, no, not the origin of life, but I'm saying like so the nebula expands outward, but then what? Like how do you make a solar system out of that? Well, it has to mix in the galaxy uh all this stuff is just going to get mixed in the galaxy basically about every 30 years another supernova in some other part of the galaxy goes off all this stuff mixes and um now the biologists have to come in and tell us uh how are we going to get life. That's another episode. They should get to work. You were saying our solar system was the consequence of multiple supernova events.

Absolutely. Snow plowing, all of this great stuff together, these heavy elements together to make rocky planets and water and all this good stuff. That's not a bad scenario. Yeah, and there's even one theory that says the origin of life, and you're probably familiar with this theory, that says the origin of life actually was the result of a nearby supernova. Because a nearby supernova, what it does is it sort of compresses the blast wave. It actually compresses the gas around it, so you can sort of form new structures in the debris of a supernova.

Like a snowplow. Yeah, yeah. So we were asking you earlier, what's new in the supernova world that you're working on? Well, the big thing that most people that study supernovae, this is the great discovery that was made in 1998, the discovery of dark energy. And it was made possible by looking at the super... There is a class of supernovae that have exactly the same intrinsic brightness. Okay.

Okay, so by looking at how faint they are in the sky, you can determine their distances very precisely. Yeah. They're in galaxies. Yeah. Those galaxies share in the Hubble Law of Expansion. Mm-hmm. share in the Hubble Law of Expansion. And so they were the key to being able to basically test the velocity-distance relationship,

which I'm perhaps... So it's like I have a light bulb here. I move it further away, and because I know a lot about that light bulb, I can tell its distance because I know a lot about it ahead of time. Exactly. So I can place that these light bulbs, which are the supernova, are actually in other galaxies, and I can tell that they're moving away, and therefore measure the expansion rate of the universe. I knew that, but I was just recapping. For effect, it was a device. That's the big thing about supernovae. Our particular research is a little more on the

remnant, because many supernovae leave neutron stars behind when you when you blow up the star you don't necessarily let the whole star you blow up the outer part of the star the inner part of the star could be so compact that the gravity can survive that and that frequently happens and it makes neutron stars and there's thousands of neutron stars in our galaxy some are in binary star systems those are the ones I like because we study these binary star systems. We can measure their periods. We can measure their rotation. So what is a black widow pulsar?

A black widow pulsar is a very tight binary, like a cataclysmic variable, where the two stars are so close together that the pulsar beam, you know, pulsar is like a big... So pulsar's a neutron star. It's a rapidly rotating neutron star with a big sort of searchlight beam of charged particles searching around, going around. It's a lighthouse.

Yeah, like a lighthouse going around, say, about 30 times a second, or say 10 to 30 times a second. So if you're at a specific point in space, you just see it flashing on and off. You'd see pulse, pulse, pulse, pulse, pulse. So instead of a 24-hour period, it's a pretty fast period. It's less than a second.

Most of them are less than a second. Some of them are a few seconds. But, you know, right about that. And so what happens is if there's another star that's in the vicinity of it, it keeps getting hit, hit, hit, hit with all this energy, these electrically charged

particles that are emitted, keep getting, they keep bombarding the other star, and basically, it's Black Widow Pulsar. The companion eats it. On that note,

I did, before we close the show, want to ask Matt to throw us a cosmic query to bring us back to remember that we were on this day, August 21st. Joe, your shirt has, where will you be on August 21st, 2017, the Great American Eclipse? Where is the eclipse in that picture? The eclipse is down there in Tennessee. In Tennessee. Okay.

But you were not in Tennessee. So let's bring this back to the eclipse day, and I think we have a cosmic query. We have one cosmic query from Ben Ratner, and that is, on a planet from a binary system, what would a solar eclipse look like, and could a star create the eclipse of the other star? Well, could a star create an eclipse of the other star?

Absolutely. star? Well, could a star create an eclipse of the other star? Absolutely. If it was a faint star occulting a bright star, that would be like what we saw today, or what people in totality saw today.

It could be a bright star occulting a faint star, and nobody would care. It's like the sun occulting a distant star. We don't care. distant star we don't care yeah we don't care about that and uh and so now i have to have a planet in there too and then the second thing yeah you've got a you've got a planet so there's you're on you got a binary star and i guess there's a planet somehow orbiting in some i imagine the orbit would be weird as well are you on that

planet or are you on a different planet i I believe you are on that planet, is my understanding. Okay. And then let's say there's a moon as well. Oh, please. Well, the moon probably is a small moon, so I'm going to neglect the moon. But yeah, no, I was assuming the planet... A planet and another planet maybe. Yeah, the planet would normally see the binaries and then every so often they would line up

and one would go in front of the other. I'm not sure it would be celebrated in any particular way, unless it was the faint one going in front of the other. I'm not sure it would be celebrated in any particular way, unless it was the faint one going in front of the bright one. That's really what creates the spectacle. Actually, maybe you could mention how we use that technique to look for exoplanets. So that's really cool.

Yeah, absolutely. Well, of course, a very popular technique, it turns out extremely useful technique for finding exoplanets, is just look at a nearby star and just watch it continuously, say, for six months or so. We have spacecraft doing this. Humans can't do that, but spacecraft can do it. I'm very patient. What happens occasionally is that a planet will wander. If there is a planet up there, it may wander across the face,

and you'll see the face of that. You won't see light from the planet, but you'll see that the light from the star has a little dip in it. Right. It's an eclipse. And then four days later, it has another little dip in it, and then another little dip in it, and then another little dip. And after about ten of these things, say hey it's regular so if it's regular it's not like

you know the weather or something so something's orbiting there's something orbiting and we're literally using the eclipse of a tiny planet so it's nowhere near a total eclipse it's an absolutely teeny tiny just enough to reduce the light intensity yes so that from earth we can tell that the star has planets, and we can start to count the number of planets they have and estimate their sizes. I mean, that's a spectacular use of the eclipse phenomenon, basically. So we see other eclipses from Earth besides just solar and lunar.

Yeah, I forgot all about those. Isn't that great? I know, it just occurred to me just now. Yeah, right. You've been listening to StarTalk All-Stars. Thank you so much for tuning in. I'm Jan Eleven, your All-Stars host. My co-host, Matt Kirshen.

Hey. Wave to the audio audience and a couple of video audiences. And our expert guest, scientist, astronomer, Joe Patterson. Thanks so much, guys, for coming. Thank you. That was so fun. Let's keep talking when the cameras are off. Salutations from the shadow of the moon, August 21st.

See you next time.