WEBVTT - Why do stars twinkle? 0:00:08.880 --> 0:00:11.360 Or Hey, do you know the song Twinkle Twinkle Little Star? 0:00:11.800 --> 0:00:14.240 I do? Yeah? Are we taking song requests now on 0:00:14.280 --> 0:00:17.520 the podcast? Now? I'm just trying to see something. How 0:00:17.520 --> 0:00:19.840 about the alphabet song? Is that something you heard as 0:00:19.840 --> 0:00:22.960 a kid. I've heard of the alphabet? Yeah? Do you 0:00:23.000 --> 0:00:25.760 want me to get my guitar? Um? Do you also 0:00:25.800 --> 0:00:28.280 know Bob Bob black Sheep? That one I'm not super 0:00:28.280 --> 0:00:32.040 familiar with, but it's another kid song? Right? Well? Did 0:00:32.080 --> 0:00:36.479 you ever realize these all have exactly the same music? 0:00:36.880 --> 0:00:40.280 What you just blew my mind? Are they all called 0:00:40.320 --> 0:00:44.120 the same like Twinkle Twinkle, Little Alphabet Black Sheep? Yeah? 0:00:44.240 --> 0:00:46.720 They all end with three bags full of twinkling a 0:00:46.800 --> 0:00:51.760 BCS and a bunch of lawsuits, maybe apparently for copyright infringement. 0:01:07.040 --> 0:01:10.280 Hi am r Handy cartoonists and the creator of PhD comics. Hi. 0:01:10.400 --> 0:01:13.280 I'm Daniel. I'm a particle physicist and a professor at 0:01:13.360 --> 0:01:16.440 UC Irvine, And like every other professor, I also play 0:01:16.520 --> 0:01:21.440 the guitar. Is that a requirement for professors? I don't know, 0:01:21.480 --> 0:01:23.240 but I live in a neighborhood of professors, and I 0:01:23.280 --> 0:01:25.600 feel like every single house I go into has a 0:01:25.600 --> 0:01:27.400 guitar on the wall. I don't know if they play 0:01:27.440 --> 0:01:30.039 it or if it's just like a demonstration object, but 0:01:30.080 --> 0:01:32.280 there's lots of guitars in this neighborhood. It's like when 0:01:32.360 --> 0:01:35.040 they were visiting some foreign country. They picked up a 0:01:35.040 --> 0:01:37.759 guitar or something on a field trip or a conference, 0:01:38.040 --> 0:01:41.720 or maybe it's just a conversation piece. Nobody actually plays. 0:01:42.640 --> 0:01:44.600 Are you supposed to play guitar? You just have one 0:01:44.640 --> 0:01:47.360 on your wall right to look cool? You could ask 0:01:47.440 --> 0:01:49.520 something to look cool. I guess if you're a professor. 0:01:49.600 --> 0:01:51.960 But you're quite an accomplished guitar player, aren't you. I 0:01:51.960 --> 0:01:54.040 don't know if I would say accomplished. But I am 0:01:54.080 --> 0:01:56.600 in a band now. Is there anyone else in your band? 0:01:57.440 --> 0:02:01.000 Not a one man band. I'm in a rock band 0:02:01.040 --> 0:02:03.640 with some friends. Oh wow, awesome. Yeah, a bunch of 0:02:03.680 --> 0:02:06.200 middle aged men having a middle age crisis. I've never 0:02:06.240 --> 0:02:10.400 heard of that happening before. That's amazing. We're called the 0:02:10.400 --> 0:02:13.440 Grateful Dad's, so shout out to my band members. But 0:02:13.560 --> 0:02:15.520 I don't think they listen to this podcast. But anyways, 0:02:15.520 --> 0:02:18.040 welcome to our podcast. Daniel and Jorge explained the university 0:02:18.080 --> 0:02:21.160 production of I Heart Radio, in which these two dads 0:02:21.200 --> 0:02:25.080 are grateful for our ability to understand anything out there 0:02:25.160 --> 0:02:28.560 in the universe and dive deep into all of the mysteries, 0:02:28.720 --> 0:02:32.959 the crazy, bonkers weirdness of our universe, the amazing quantum 0:02:32.960 --> 0:02:37.280 frothing foam, the incredible cosmic conundrums, all of the stuff 0:02:37.320 --> 0:02:39.400 that you want to know, the answers to the things 0:02:39.400 --> 0:02:41.760 that frame our existence, that tell us how we got 0:02:41.800 --> 0:02:44.720 here and where the universe is going. We explore all 0:02:44.760 --> 0:02:47.320 of these questions and more. Yeah, because it is a 0:02:47.360 --> 0:02:51.639 pretty amazing and incredible universe, full of exciting and crazy 0:02:51.720 --> 0:02:53.720 things happening, all at the same time as a lot 0:02:53.720 --> 0:02:56.680 of sleepy things happening, a lot of interesting tunes to 0:02:56.760 --> 0:02:59.959 putudiou sleep. I was wondering what you were talking about there, 0:03:00.240 --> 0:03:02.840 sleepy things happening. It was like a rhel We're losing him. 0:03:02.880 --> 0:03:05.880 Is he falling asleep over there? I don't think Twinkle Twinkle, 0:03:05.880 --> 0:03:07.840 Little Star is supposed to put anybody to sleep? Is it? 0:03:07.840 --> 0:03:10.400 It's in it a bedtime song? Oh maybe not. Maybe 0:03:10.440 --> 0:03:13.040 I didn't grow up here, so these were not songs 0:03:13.040 --> 0:03:14.880 that I was sunk to. I think it's more of 0:03:14.919 --> 0:03:17.520 a campfire song. You're sitting there out in nature, looking 0:03:17.560 --> 0:03:20.120 up at the stars and wondering, you know, what they are. 0:03:20.200 --> 0:03:23.280 It's one of the oldest questions humans have been asking 0:03:23.320 --> 0:03:26.240 about the nature of the cosmos. What is out there? 0:03:26.280 --> 0:03:28.840 What is sending us those beams of light? Yeah, it's 0:03:28.880 --> 0:03:32.080 pretty incredible to think that, you know, the earliest humans 0:03:32.160 --> 0:03:34.240 were looking up at the same sky we were, and 0:03:34.280 --> 0:03:36.880 they were probably asking themselves the same questions, like what 0:03:37.080 --> 0:03:39.480 is that Chinese little dought there? And how far away 0:03:39.520 --> 0:03:42.040 is it exactly? And how many quarks are inside the 0:03:42.080 --> 0:03:44.240 heart of a neutron star. I think that's the question 0:03:44.280 --> 0:03:47.720 people have been asking for thousands of years, right if 0:03:47.760 --> 0:03:50.280 they were pretty smart. Cavement, I guess Warren Cavement the 0:03:50.280 --> 0:03:55.040 original particle colliders getting rocks together exactly me makes smaller rocks. 0:03:55.320 --> 0:03:57.680 But it's true, it's an age old question, and there's 0:03:57.680 --> 0:04:00.880 a grand cosmic scale to these questions, because those photons 0:04:01.160 --> 0:04:05.400 departed those stars millions of years or billions of years 0:04:05.440 --> 0:04:09.160 before even cavemen evolved. Yeah, definitely, starts have been around 0:04:09.200 --> 0:04:13.000 for billions, maybe trillions of years, way before people were 0:04:13.000 --> 0:04:15.080 looking at them, and they've been sending their light to 0:04:15.280 --> 0:04:17.360 us for all that time. And some of that light 0:04:17.440 --> 0:04:19.920 is just now getting to us right now, And it's 0:04:19.960 --> 0:04:23.360 incredible to think about how that light actually arrives here. 0:04:23.680 --> 0:04:26.880 A tiny little photon emitted by a star billions and 0:04:26.960 --> 0:04:30.680 billions of miles away, has to fly through an incredible 0:04:30.720 --> 0:04:34.000 amount of universe, dodging all sorts of kinds of stuff 0:04:34.040 --> 0:04:37.880 just to land in your eyeball. It's an incredible journey, 0:04:37.880 --> 0:04:39.720 and frankly, it's amazing to me that any of the 0:04:39.760 --> 0:04:42.280 photons survive it. Yeah, I mean, who knows what that 0:04:42.400 --> 0:04:44.719 photon has been through, right Like it could have maybe 0:04:44.760 --> 0:04:48.040 gone around a black hole or barely dodged an asteroid 0:04:48.120 --> 0:04:50.280 or a comment, you know, made it through an atmosphere, 0:04:50.400 --> 0:04:53.479 dodge all those bolly kills of air in our atmosphere, 0:04:53.600 --> 0:04:55.760 and just to go into your eyeball, or just to 0:04:55.839 --> 0:04:58.159 hit a rock, and nobody even observes it. That's the 0:04:58.200 --> 0:05:01.679 thing that frustrates me. How many photons carrying tiny little 0:05:01.680 --> 0:05:05.400 clues about the universe just go totally unobserved. They fade 0:05:05.400 --> 0:05:08.600 away like an old rock star. They're like little presents 0:05:08.640 --> 0:05:11.400 that nobody unwraps. You know, each one has a clue 0:05:11.400 --> 0:05:13.159 about the kind of star that it came from, the 0:05:13.240 --> 0:05:15.400 history of that star what was going on in that 0:05:15.440 --> 0:05:18.480 star at that moment, and then just boom, nobody gathers 0:05:18.480 --> 0:05:21.080 and it just goes like splat on the sidewalk. Yeah, 0:05:21.160 --> 0:05:23.840 it's pretty cool to think that every star you see, 0:05:23.880 --> 0:05:26.280 I mean it was generated by a whole sun, right, 0:05:26.400 --> 0:05:30.719 basically a giant ball of of fusion powered fire that 0:05:30.880 --> 0:05:33.040 was shooting photons in every direction, and some of them 0:05:33.120 --> 0:05:35.279 make it out to here. It gives you a sense 0:05:35.279 --> 0:05:38.760 for the incredible size and brightness of these stars that 0:05:38.839 --> 0:05:41.360 you can see them from so far away. Imagine if 0:05:41.400 --> 0:05:44.680 your friend in Los Angeles had a flashlight that you 0:05:44.720 --> 0:05:47.160 could see in New York, you would think, oh my gosh, 0:05:47.160 --> 0:05:50.760 that must be a crazy, crazy bright flashlight. Right. Well, 0:05:50.760 --> 0:05:53.920 these stars are so much further away, and yet you 0:05:53.960 --> 0:05:57.159 can see them with your naked eyes. It's incredible that 0:05:57.240 --> 0:05:59.760 these photons make it over this distance. I feel like 0:05:59.800 --> 0:06:02.640 something I realized only recently was the fact that the 0:06:02.680 --> 0:06:05.400 reason why stars looked like little pin points in the sky. 0:06:05.560 --> 0:06:08.039 It's not that they are pinpoints, or it's not that 0:06:08.080 --> 0:06:10.160 the sun is so far away that the sun keeps 0:06:10.160 --> 0:06:12.599 getting smaller as it goes away. It's it's it's literally 0:06:12.720 --> 0:06:16.480 just like one photo receptor in my eyeball getting activated 0:06:16.640 --> 0:06:19.520 by one photon. You're saying that stars are like single 0:06:19.640 --> 0:06:23.960 eye pixels in your mind basically, right, Yeah, they're just well, 0:06:24.120 --> 0:06:25.599 what I think of as a star, or what I 0:06:25.640 --> 0:06:27.799 see as a star is really just one eye pixel, 0:06:27.960 --> 0:06:30.520 right like, Like it doesn't really tell me anything about 0:06:30.560 --> 0:06:32.680 its shape or size. Yeah, it's fascinating to think about 0:06:32.680 --> 0:06:35.320 how photons spread out from that star and then sort 0:06:35.320 --> 0:06:37.880 of get more and more distant from their neighbors. And 0:06:37.920 --> 0:06:39.880 to see a star that's really far away, you only 0:06:39.920 --> 0:06:43.039 really just need one photon, And even if that photon 0:06:43.160 --> 0:06:45.760 was created with billions of other photons really near it, 0:06:45.960 --> 0:06:48.359 they all shoot out at slightly different angles, and so 0:06:48.480 --> 0:06:51.479 by the time they arrives on Earth, it's basically alone. 0:06:51.520 --> 0:06:54.520 It's the only photon that came from that star. Of course, 0:06:54.680 --> 0:06:56.680 there are more coming behind it, but that's why the 0:06:56.720 --> 0:06:59.560 stars seem much dimmer, of course, the further way they are, 0:06:59.600 --> 0:07:01.839 because the photons are now spread out over a much 0:07:02.040 --> 0:07:05.039 larger area, and so only a single cone in your 0:07:05.040 --> 0:07:07.840 eye might register a photon from that star. Yeah, it 0:07:07.880 --> 0:07:09.679 kind of makes you wonder like if we had bigger 0:07:09.720 --> 0:07:12.080 photo receptors in our eyeballs, you know, like if our 0:07:12.080 --> 0:07:15.120 pixels were bigger, the stars would look bigger, right, And 0:07:15.160 --> 0:07:17.560 if they were smaller they would look like smaller pinpoints. 0:07:17.680 --> 0:07:19.960 I suppose if they were smaller, eventually we could even 0:07:20.000 --> 0:07:23.480 resolve the size and the shape of the stars. You think, 0:07:23.520 --> 0:07:26.480 so eventually eventually, right, because there is that information there. 0:07:26.520 --> 0:07:28.160 I mean, if you have a large enough telescope for 0:07:28.200 --> 0:07:31.360 close enough stars, you can definitely resolve the size of 0:07:31.400 --> 0:07:33.520 the star. You think, maybe like a hawk can see 0:07:33.560 --> 0:07:36.960 the somehow, the contours of Alpha Centauri or something, or 0:07:36.960 --> 0:07:40.480 the Sagittarius. We shouldn't be inviting eagles to astronomy conferences 0:07:40.520 --> 0:07:42.920 for sure, Yeah, or at least on the podcast. I 0:07:42.960 --> 0:07:44.880 have questions for them. I want to interview the first 0:07:44.920 --> 0:07:46.760 hawks astronomer. Now I hear they're just a bunch of 0:07:48.200 --> 0:07:50.080 ye astronomy is for the birds. But I hear that 0:07:50.120 --> 0:07:53.680 have a lot of feathers in their publishing caps. But anyways, 0:07:53.760 --> 0:07:55.680 it's just it is interesting to look at a star 0:07:55.760 --> 0:07:58.000 in the night sky and see it twinkle, right. It 0:07:58.080 --> 0:08:00.600 kind of makes you wonder, like, why is it twink 0:08:01.000 --> 0:08:03.320 wiz it actually twinkling? Or is it does it just 0:08:03.360 --> 0:08:05.600 look like it's twinkling. Yeah, And this is a question 0:08:05.640 --> 0:08:07.920 that people have been asking for a long long time, 0:08:08.200 --> 0:08:10.360 not just what are the stars, but what is the 0:08:10.400 --> 0:08:13.160 fact that they're twinkling? Tell us about them? Why do 0:08:13.240 --> 0:08:16.080 different stars seem to twinkle different amounts? And it's a 0:08:16.160 --> 0:08:19.200 question with lots of different layers of answers, because it 0:08:19.200 --> 0:08:22.640 turns out there's lots of different reasons that stars can twinkle. Yeah, 0:08:22.720 --> 0:08:24.840 And it's a question that apparently inspired a song a 0:08:24.880 --> 0:08:28.240 long time ago. Three different songs. M have you dug 0:08:28.240 --> 0:08:30.600 into it? Which one came first, Twinkle Twinkle, Little Star 0:08:30.760 --> 0:08:33.360 or the ABC song. Yeah. Actually, turns out the song 0:08:33.480 --> 0:08:37.920 for Twinkle Twinkle is derived from something composed by Mozart, 0:08:38.120 --> 0:08:41.720 which is inspired by something even earlier, And then later 0:08:42.080 --> 0:08:45.040 an American music publisher adapted the tune to fit the 0:08:45.080 --> 0:08:47.560 alphabet song. So Twinkle Twinkle came first, and then the 0:08:47.600 --> 0:08:50.840 alphabet Interesting, but even Twinkle Twinkle was based on something else. 0:08:50.960 --> 0:08:53.680 All music, of course, is inspired by previous music. Right, 0:08:53.720 --> 0:08:56.120 It's all derivative, right, right, We're all made out of 0:08:56.120 --> 0:08:58.520 start us, even the songs about stars. Does your band 0:08:58.520 --> 0:09:02.280 play original music or only cover? So far we're only covers. 0:09:02.320 --> 0:09:05.000 Yet I say, you got twinkle twinkle, you've got Bob Bob, 0:09:05.000 --> 0:09:08.120 black Sheep, you've got the alphabet song. A huge variety, 0:09:08.720 --> 0:09:11.960 that's right. We cover everything from back to Pink Floyd. 0:09:12.160 --> 0:09:14.439 But anyways, this is an interesting question, and so today 0:09:14.440 --> 0:09:24.280 on the podcast, we'll be asking what makes a star twinkle? Twinkle? Right, 0:09:24.280 --> 0:09:27.400 not tinkle. It's not that kind of podcast. We don't 0:09:27.400 --> 0:09:32.280 ask stars about their personal habits, about their bodily functions. 0:09:32.559 --> 0:09:35.360 We do sort of ask a lot about how the 0:09:35.440 --> 0:09:38.240 insights of stars all right, and and the gases that 0:09:38.400 --> 0:09:40.240 erupt from it. And that's true when you talk about 0:09:40.280 --> 0:09:42.880 the waste products of stars and how they can be 0:09:43.000 --> 0:09:46.760 the compost that nourishes the formation of a future solar system. 0:09:46.760 --> 0:09:48.840 They're all part of the life cycle. Yeah, yeah, it's 0:09:48.880 --> 0:09:51.040 all physics. And so maybe next time we should ask 0:09:51.080 --> 0:09:56.319 what makes its start tinkle? Welcome to our spinoff podcast, 0:09:56.520 --> 0:09:59.360 Inappropriate Physics. But it's a fascinating question. I think a 0:09:59.360 --> 0:10:02.040 lot of people i'd have some sense of the common 0:10:02.080 --> 0:10:04.440 answer to this question, but if you dig deeper, it 0:10:04.440 --> 0:10:07.680 turns out there's lots of different fascinating physics that might 0:10:07.760 --> 0:10:10.120 make stars twinkle. Yeah, it turns out. There's not just 0:10:10.200 --> 0:10:14.280 one reason stars twinkle. There are several reasons. But the 0:10:14.320 --> 0:10:15.880 basic effect is that when you look at the star 0:10:15.920 --> 0:10:18.480 in the night sky, it's sort of doesn't look like 0:10:18.520 --> 0:10:22.800 a constant dot, right, or a constant dots shining. It 0:10:22.840 --> 0:10:24.720 looks sort of like it's blinking on and off a 0:10:24.720 --> 0:10:27.079 little bit. Yeah, exactly, stars look a little bit like 0:10:27.120 --> 0:10:30.320 they blink like they're not just like a laser focused 0:10:30.400 --> 0:10:33.160 at your eyeball. Yeah, it's it's it's almost like something 0:10:33.320 --> 0:10:35.679 is turning it on and off a little bit, or 0:10:35.800 --> 0:10:38.280 something is interfering with it, something is getting between you 0:10:38.480 --> 0:10:41.440 and the star. All right, So we'll dig into this 0:10:41.520 --> 0:10:44.000 question what makes its start twinkle? But first we were 0:10:44.000 --> 0:10:45.720 wondering how many people either there have thought about this 0:10:45.840 --> 0:10:49.560 question when they were singing the song or otherwise, And 0:10:49.600 --> 0:10:51.880 so Daniel went out there into the did you go 0:10:51.880 --> 0:10:53.960 into the internet or to the u c I campus 0:10:54.000 --> 0:10:56.439 this time? These are answers from the internet. So thank 0:10:56.520 --> 0:10:59.280 you to everybody who participated. And if you like to 0:10:59.480 --> 0:11:02.240 put your mind to the test for future episodes and 0:11:02.320 --> 0:11:05.360 let people hear what you think about hard physics problems, 0:11:05.440 --> 0:11:08.320 please don't be shy right to us, do questions, add 0:11:08.400 --> 0:11:10.800 Daniel and Jorge dot com. That's right, and you can 0:11:10.800 --> 0:11:14.360 also go visit Daniel. Do you see Irvine right and 0:11:14.480 --> 0:11:16.280 hope to run into him in the middle of campus. 0:11:16.760 --> 0:11:19.160 That's right. I'm on canvas at Easy Irvine. I have 0:11:19.240 --> 0:11:21.720 office hours, so come on stop by to think about 0:11:21.720 --> 0:11:24.120 it for a second. Why do you think stars twinkle? 0:11:24.920 --> 0:11:27.559 Here's what people had say. I don't think stars twinkle. 0:11:28.200 --> 0:11:31.240 I think their photons are disrupted by temperature and pressure 0:11:31.360 --> 0:11:35.199 differentials in our atmosphere, giving us the appearance of twinkling. 0:11:35.280 --> 0:11:38.120 I imagine it's the same phenomenon that one witnesses looking 0:11:38.120 --> 0:11:40.719 over hot asphalt and seeing the horizon winkle. And I 0:11:40.840 --> 0:11:43.320 venture to guess that they don't twinkle when observed from 0:11:43.360 --> 0:11:46.920 the International Space Station. Well, I guess it depends what 0:11:46.960 --> 0:11:49.840 we mean by blink. The first thing that comes to 0:11:49.880 --> 0:11:54.840 mind is if we're observing a star and something moves 0:11:54.880 --> 0:11:58.040 between us and the star, like a planet, it's gonna 0:11:58.240 --> 0:12:01.679 appear to have blink, I guess. But the star itself 0:12:01.760 --> 0:12:04.760 isn't actually doing anything. It's just something's moved in front 0:12:04.800 --> 0:12:07.000 of it, so it looks like something's happened to it. 0:12:07.600 --> 0:12:11.440 I think that might be what the blink is. In general, 0:12:11.600 --> 0:12:17.800 I don't think stars actually blink, but I can envision 0:12:18.920 --> 0:12:24.360 dust clouds were particularly large planets moving between us and 0:12:24.480 --> 0:12:31.320 that star, making them appear to blink or dim significantly. 0:12:32.000 --> 0:12:35.359 It makes us star blink when the stars about to explode, 0:12:35.840 --> 0:12:39.920 that is one. That is one reason the atmosphere makes 0:12:39.920 --> 0:12:44.080 the start blank to right h And then a lot 0:12:44.120 --> 0:12:47.920 of stars are binary pairs actually, and some of them 0:12:47.960 --> 0:12:52.000 I think can be uh rotating around really quick, and 0:12:52.200 --> 0:12:55.199 that would make the star appear like it's blinking. Well, 0:12:55.200 --> 0:12:57.480 I know, the blinking that we see from here on Earth, 0:12:57.880 --> 0:13:00.960 like the twinkling star, that's more to do with our 0:13:01.000 --> 0:13:04.200 atmosphere than the star itself. But I do know that 0:13:04.240 --> 0:13:08.400 stars also blink over the course of weeks and months. 0:13:09.160 --> 0:13:12.120 I know Bill just did recently. I'm not sure what 0:13:12.120 --> 0:13:14.000 the cause was, though, so if I had to guess, 0:13:14.000 --> 0:13:17.080 I would think it would be maybe gas clouds, um 0:13:17.240 --> 0:13:21.040 or even transitting planets. I don't know. I think that 0:13:21.440 --> 0:13:26.320 what makes us start blink maybe some kind of intern 0:13:26.720 --> 0:13:32.400 interference with any object objects that may cross in the 0:13:32.559 --> 0:13:38.440 path between the star and the person who observes the blinking. 0:13:38.880 --> 0:13:41.679 I would say that What makes us star blink is 0:13:41.760 --> 0:13:47.600 the disturbances in the atmosphere, similar to what we see 0:13:47.800 --> 0:13:52.160 when looking at distant street lights. There are um, you know, 0:13:52.280 --> 0:13:56.000 small air currents, pockets of warm and cold air that 0:13:56.040 --> 0:14:00.839 are constantly moving that through refraction, cause distant, tiny light 0:14:00.880 --> 0:14:04.240 sources such as stars to blink when viewed. Although that 0:14:04.320 --> 0:14:08.600 just might be my view as an amateur astronomer. All right, 0:14:08.720 --> 0:14:11.160 people seem to have pretty strong opinions here. I mean 0:14:11.200 --> 0:14:13.280 a few people didn't know, but a lot of people 0:14:13.320 --> 0:14:15.280 seem to think what was going on. Yeah, there's a 0:14:15.280 --> 0:14:18.400 strong vein here of people thinking that stars are interfered 0:14:18.440 --> 0:14:21.000 with by our atmosphere. Yeah. A lot of people said 0:14:21.000 --> 0:14:23.840 that it's not that the stars actually blinked, like at 0:14:23.840 --> 0:14:26.240 the source, like the star itself. It's just that it 0:14:26.360 --> 0:14:28.880 just looks like it's blinking. And that's a fascinating answer 0:14:28.920 --> 0:14:32.240 because it suggests that the photons are like uninterrupted for 0:14:32.440 --> 0:14:36.040 billions and billions of years and then just like micro 0:14:36.240 --> 0:14:39.880 seconds before they hit your eyeball, that's when they get twinkled. Yeah, 0:14:39.920 --> 0:14:41.680 that's what we tell people who come listen to our band. 0:14:41.760 --> 0:14:44.240 That's thought that we sound bad. It's just said you 0:14:44.280 --> 0:14:46.640 know our perfect sounds. Somebody guests distorted it on the 0:14:46.680 --> 0:14:48.200 way to your ear. That's right. That's why you have 0:14:48.280 --> 0:14:50.880 forced them to plug indirectly to your instruments, right, so 0:14:50.920 --> 0:14:54.320 they can hear the adulterated intended version of your music. 0:14:54.480 --> 0:14:58.200 That's right. Yes, the direct neural download. That's the next step. Actually, 0:14:58.200 --> 0:15:00.480 I know somebody with hearing loss and have a new 0:15:00.600 --> 0:15:03.680 kind of hearing aid that allows for a Bluetooth connection 0:15:04.120 --> 0:15:06.520 so that the sound doesn't have to go through the air. 0:15:06.680 --> 0:15:10.440 They can just hear the original unadulterated sound. Wow, that's 0:15:10.520 --> 0:15:13.240 really interesting. I wonder if it sounds better or different. Oh, 0:15:13.280 --> 0:15:15.680 it's much clearer. They can go to presentations, they can 0:15:15.720 --> 0:15:18.560 hear in church. Now, it's much better than just amplifying 0:15:18.560 --> 0:15:20.720 the sound through the air. Sounds great, And that means 0:15:20.760 --> 0:15:23.520 you can also hit the mute button, I imagine at 0:15:23.600 --> 0:15:26.400 church or at a professor lecture, that's right. It probably 0:15:26.440 --> 0:15:28.680 also means that you can hack them and you can 0:15:28.720 --> 0:15:31.200 like pipe in the Grateful Dads or something else. Yeah, 0:15:31.320 --> 0:15:33.880 much better than a professor lecture for sure, especially if 0:15:33.880 --> 0:15:36.760 you're getting it at the source. But anyways, it's there's 0:15:36.840 --> 0:15:38.760 some interesting ideas here. A lot of people say, it's 0:15:38.800 --> 0:15:41.360 not the stars that are actually blinking, it's somehow like 0:15:41.440 --> 0:15:44.480 the atmosphere that's making them blink or somehow making them 0:15:44.480 --> 0:15:46.880 look like they're blinking. So Daniel, maybe step us through. 0:15:47.080 --> 0:15:50.200 What are some of the actual reasons why stars sprinkle? Well, 0:15:50.200 --> 0:15:52.920 our atmosphere is the number one reason. And this is 0:15:52.960 --> 0:15:56.480 basically why we have space telescopes, because it's not a 0:15:56.600 --> 0:15:59.960 very nice to look at distant stars through the atmosphere 0:16:00.160 --> 0:16:03.320 because while the air seems clear to you, it actually 0:16:03.320 --> 0:16:06.640 can make light zig and zag a little bit because 0:16:06.680 --> 0:16:09.960 it's a slightly different temperatures and slightly different densities. And 0:16:09.960 --> 0:16:13.440 that's sort of like looking through glass with impurities in it. 0:16:13.560 --> 0:16:15.920 That's interesting. But I guess like if I look at 0:16:15.960 --> 0:16:19.600 something through a glass or like a hazy glass, it 0:16:19.640 --> 0:16:21.920 doesn't make the light source twinkle, It just makes it 0:16:21.920 --> 0:16:24.440 look dimmer. Well, what a glass does It bends the light, right, 0:16:24.480 --> 0:16:26.320 That's how a lens works. And so if you have 0:16:26.440 --> 0:16:30.080 glass that has like varying densities and varying temperatures in it, 0:16:30.120 --> 0:16:32.560 for example, then it will change the path of that light. 0:16:32.680 --> 0:16:34.440 And so what happens to the photons is they hit 0:16:34.480 --> 0:16:37.360 the atmosphere. Is not that they're like destroyed, is that 0:16:37.400 --> 0:16:40.000 they're just change direction. And so for you to see 0:16:40.000 --> 0:16:42.000 a star, you need like a direct line of sight 0:16:42.080 --> 0:16:44.920 between you and the star. But if some photons are deflected, 0:16:45.160 --> 0:16:47.320 then you don't see them. Those photons might land to 0:16:47.400 --> 0:16:49.880 your left or to your right or somewhere else. They 0:16:49.920 --> 0:16:52.560 still hit the earth, but they're not hitting your eye anymore. 0:16:52.600 --> 0:16:55.080 So to your eye it looks like the star is 0:16:55.120 --> 0:16:58.160 twinkling because the stream of photons is interrupted. Right. But 0:16:58.160 --> 0:16:59.640 but I guess what I mean is that the difference 0:16:59.640 --> 0:17:02.280 between like a glass and the atmosphere is that the 0:17:02.320 --> 0:17:05.760 atmosphere is sort of like always changing. Right, there's wind, 0:17:06.000 --> 0:17:09.280 and there's you know, variations and clouds, and so it's 0:17:09.320 --> 0:17:12.000 it makes the starts twinkle because the air is sort 0:17:12.000 --> 0:17:14.639 of like moving and waving around in front of you, 0:17:15.080 --> 0:17:17.080 whereas it like a glass doesn't. Right, Like a glass 0:17:17.080 --> 0:17:19.280 doesn't make a start twinkle. That's right, a glass wouldn't 0:17:19.280 --> 0:17:21.359 make a start twinkle. It might deflect the path, but 0:17:21.400 --> 0:17:23.199 if you find the right location, you could see a 0:17:23.240 --> 0:17:26.440 constant stream of light flowing through the glass. But as 0:17:26.480 --> 0:17:29.439 you say, air is constantly changing, right, The wind. The 0:17:29.440 --> 0:17:32.760 atmospheric conditions are constantly changing, and so the path of 0:17:32.760 --> 0:17:35.359 a photon through the air is not constant. So if 0:17:35.359 --> 0:17:37.680 you're just standing there with your eyeball in one location, 0:17:37.960 --> 0:17:40.160 you're not going to get all the photons that come 0:17:40.240 --> 0:17:42.560 from that star. Well, it's kind of interesting because the 0:17:42.600 --> 0:17:45.760 atmosphere makes the stars twinkle like it makes the photons 0:17:45.800 --> 0:17:48.200 sometimes reach your eyeball and sometimes not. But you're saying 0:17:48.240 --> 0:17:50.560 that it can also bend the photons, But it doesn't 0:17:50.560 --> 0:17:53.600 make the stars kind of wavy? Does it? Right? In principle, 0:17:53.680 --> 0:17:56.120 it does if you could capture all of those photons, 0:17:56.160 --> 0:17:58.639 like if you had a huge collection device, then you 0:17:58.680 --> 0:18:01.160 would still see the star because as the deflected photons 0:18:01.200 --> 0:18:03.440 would land in your collection device, and then you would 0:18:03.440 --> 0:18:05.920 think the star came from a different place. And so 0:18:06.040 --> 0:18:08.560 because you have a small collection device, just your eyeball, 0:18:08.640 --> 0:18:10.919 you're missing some of those photons, so it looks like 0:18:10.960 --> 0:18:14.200 the star twinkles rather than dances. There's actually another really 0:18:14.240 --> 0:18:17.560 interesting effect called stellar aberration, which means that the stars 0:18:17.560 --> 0:18:20.320 are not actually where they look like they are because 0:18:20.359 --> 0:18:22.800 they have relative velocity to the Earth. So by the 0:18:22.840 --> 0:18:25.399 time the light gets here, the stars have sort of 0:18:25.600 --> 0:18:28.120 moved away from where they appear to be. But that's 0:18:28.119 --> 0:18:29.919 a different thing. It doesn't cause the stars to twinkle, 0:18:30.080 --> 0:18:32.399 just causes them to be somewhere other than where they 0:18:32.440 --> 0:18:35.880 appear to be. I see, that's a different song altogether. 0:18:36.200 --> 0:18:39.880 That's more like a Baba Black stellar aberration. Yeah. Historically 0:18:39.880 --> 0:18:41.960 it is actually really important because it's one clue that 0:18:41.960 --> 0:18:44.520 we use against the either hypothesis. People are trying to 0:18:44.600 --> 0:18:47.320 understand how light propagated through the universe, and they thought 0:18:47.359 --> 0:18:50.040 maybe there's ether, but then Michaelson and Morley showed that 0:18:50.040 --> 0:18:52.280 there couldn't be either. Some people thought, oh, well, maybe 0:18:52.320 --> 0:18:54.880 we are stuck in a blob of ether that travels 0:18:54.880 --> 0:18:57.359 with the Earth, but then we wouldn't have stellar aberration. 0:18:57.600 --> 0:19:00.200 But anyway, back to twinkling stars. Yeah, I think you're 0:19:00.200 --> 0:19:02.159 saying is that the Start is shooting this train of 0:19:02.200 --> 0:19:04.439 photons add us and they're all coming sort of in 0:19:04.480 --> 0:19:07.639 a street line to our eyeballs. But some of them, 0:19:07.680 --> 0:19:09.960 like hit a pocket of hot air and get deflected, 0:19:10.040 --> 0:19:13.119 or they happen to hit a molecule of nitrogen in 0:19:13.160 --> 0:19:15.359 the atmosphere and it doesn't make it out to us. 0:19:15.400 --> 0:19:18.919 And so this train of photons is interrupted, and that 0:19:19.200 --> 0:19:21.040 is making it look like it's turning on and off 0:19:21.080 --> 0:19:23.320 to our eyeballs. That's exactly right. And then if you 0:19:23.359 --> 0:19:26.959 look at something slightly bigger, like a planet, which is closer, 0:19:27.040 --> 0:19:30.160 you're getting multiple streams of photons from that planet. It's 0:19:30.200 --> 0:19:31.840 not so far away that it just looks like a 0:19:31.880 --> 0:19:34.200 point source. It's like a little disc in the sky. 0:19:34.400 --> 0:19:37.200 And so while some of those photons may get scattered 0:19:37.240 --> 0:19:39.560 from one stream, you're pretty much always getting them from 0:19:39.560 --> 0:19:42.200 another stream. And so a planet looks like a little 0:19:42.240 --> 0:19:45.080 hazy because the atmosphere or its edges might wiggle a 0:19:45.119 --> 0:19:47.680 little bit. But a planet doesn't twinkle because it doesn't 0:19:47.680 --> 0:19:51.320 get like all of its streams interrupted at once, unless 0:19:51.320 --> 0:19:54.920 it's maybe like a super cloudy day, right or you know, 0:19:55.080 --> 0:19:57.520 particularly kind of hazy night. Yeah, it could be, you know, 0:19:57.560 --> 0:20:00.320 if something passes between you and the planet, like an 0:20:00.359 --> 0:20:02.520 eagle or something, it can block the view, or if 0:20:02.560 --> 0:20:05.399 it's like a huge blob of gas hot gas somewhere 0:20:05.400 --> 0:20:07.720 in the atmosphere, it could distort it. But twinkling is 0:20:07.760 --> 0:20:09.919 not something you're going to see regularly from a planet 0:20:09.960 --> 0:20:12.320