WEBVTT - How to Find an Exoplanet 0:00:00.160 --> 0:00:07.200 Brought to you by Toyota. Let's go places. Welcome to 0:00:07.400 --> 0:00:14.400 Forward Thinking. Hey then, and welcome to Forward Thinking the 0:00:14.560 --> 0:00:17.360 podcast and looks at the future, and says citizens of 0:00:17.360 --> 0:00:21.560 the Universe, recording angels, we have returned to claim the pyramids. 0:00:21.800 --> 0:00:27.360 I'm Jonathan Strickland and I'm Joe McCormick. Hey, Joey, you 0:00:27.360 --> 0:00:32.280 you like star gazing, right I do? And Lauren you 0:00:32.400 --> 0:00:36.720 like planets right? Um? Okay, so we've established that we 0:00:36.760 --> 0:00:41.360 are all, you know, amateur astronomers. Uh. One of the 0:00:41.400 --> 0:00:43.760 things I've always thought would be really cool would be 0:00:44.000 --> 0:00:48.839 to actually make one of those discoveries of an exoplanet. Um. 0:00:48.880 --> 0:00:51.640 You know, it's it's just an interesting idea of being 0:00:51.680 --> 0:00:55.480 able to say I have discovered the presence of another 0:00:55.640 --> 0:01:00.360 body orbiting around a distant star. So it got me 0:01:00.400 --> 0:01:04.200 to thinking, you know, how hard is that? And um, 0:01:04.280 --> 0:01:07.759 it turns out it's pretty hard. Well, it's getting easier. 0:01:07.800 --> 0:01:10.200 I mean it's certainly easier than it was a few 0:01:10.240 --> 0:01:13.000 thousand years ago. Yeah. Well a few thousand years ago 0:01:13.080 --> 0:01:16.920 I'd say it was impossible. Yes, why is that? I mean, 0:01:17.040 --> 0:01:19.959 why can't we just look up and and see planets 0:01:20.160 --> 0:01:23.759 all throughout the Milky Way for example. Well, they don't 0:01:23.800 --> 0:01:27.479 emit electromagnetic radiation the way that stars do. Yeah, well 0:01:27.520 --> 0:01:31.200 they might, they might emit some frequencies, they certainly do. Yes, No, 0:01:31.319 --> 0:01:34.240 that was a very scientifically inaccurate thing for me to say, Um, 0:01:34.240 --> 0:01:39.000 they don't emit as much, and they don't emit light 0:01:39.160 --> 0:01:41.920 their own They might get it reflected back from the 0:01:41.959 --> 0:01:45.440 star and they're going to fade away because they're very 0:01:45.480 --> 0:01:48.880 far and they're very small, and they're very dim compared 0:01:48.920 --> 0:01:53.200 to the stars. But I was actually curious when you 0:01:53.240 --> 0:01:56.960 think about exo planets. Surely somebody must have guessed at 0:01:57.000 --> 0:01:59.760 this before we detected they were there, and so who 0:01:59.840 --> 0:02:02.760 were the first people to actually suggest that there were 0:02:02.800 --> 0:02:06.680 other planets out there that were different from stars. Well, 0:02:06.680 --> 0:02:09.800 there's there's a lot of different philosophers who have talked 0:02:09.800 --> 0:02:13.440 about this, um, even before we got to the heliocentric 0:02:13.520 --> 0:02:16.720 model of our solar system. So if you want to 0:02:16.720 --> 0:02:19.600 go way back, you had a couple of chuckle heads, 0:02:19.880 --> 0:02:25.240 Aristotle and Epicurus, who were were Yeah, they were just 0:02:25.360 --> 0:02:28.520 you know, they're they're sitting there, you know, taking their 0:02:28.639 --> 0:02:32.000 lunch on the edge of giant stone work, you know, 0:02:32.040 --> 0:02:34.239 the hard hats on their heads. I get a lot 0:02:34.280 --> 0:02:37.840 of my historical knowledge from the flint stones, so uh, 0:02:38.000 --> 0:02:40.680 just roll with me on this. Anyway, they were actually 0:02:40.680 --> 0:02:44.239 having a debate, and Epicurus said that he believed the 0:02:44.320 --> 0:02:48.120 universe to be infinite, and therefore it would contain an 0:02:48.120 --> 0:02:51.320 infinity of worlds within it. By definition, if the universe 0:02:51.480 --> 0:02:55.360 is completely infinite, then everything is unnumbered. I mean, you 0:02:55.400 --> 0:03:00.480 have just a countless number of everything's, including other worlds. Um. Now, 0:03:00.520 --> 0:03:03.880 Aristotle said he believed the Earth was at the center 0:03:03.919 --> 0:03:07.200 of the universe and therefore was unique. You can only 0:03:07.240 --> 0:03:10.160 have one center, and he didn't think that because he 0:03:10.200 --> 0:03:12.520 was stupid. I mean, that was a thing that made 0:03:12.560 --> 0:03:15.840 sense to think back then, before we had telescopes and 0:03:15.960 --> 0:03:19.760 modern astronomical equipment, it really did seem like the Earth 0:03:19.840 --> 0:03:21.880 was the center of the universe. It didn't seem to move. 0:03:22.000 --> 0:03:24.280 Oh sure, sure, it seems like you're standing still and 0:03:24.320 --> 0:03:27.400 that the sky is moving around you. So therefore, yeah, 0:03:27.520 --> 0:03:31.560 obviously you're the one who's on the stationary uh rock, 0:03:32.000 --> 0:03:36.640 and everything else just moves in spheres around you and uh. 0:03:36.720 --> 0:03:39.240 As it turns out, that was a pretty popular view 0:03:39.240 --> 0:03:42.080 for a long time. Epicurus is view was not the 0:03:42.120 --> 0:03:45.640 most widely accepted Aristotles, however, was for quite some time. 0:03:46.280 --> 0:03:51.320 And um so even with epicurus view of the infinity 0:03:51.400 --> 0:03:55.080 world type of approach, it didn't necessarily mean that he 0:03:55.160 --> 0:03:58.960 thought worlds were orbiting around stars. He just thought that 0:03:59.000 --> 0:04:01.440 there would be other world olds. There are other worlds 0:04:01.480 --> 0:04:06.800 than these for my Dark Tower fans out there. Um. 0:04:06.840 --> 0:04:11.119 But then you get Copernicus coming around in saying, hey, 0:04:11.160 --> 0:04:16.240 you know what, I think the Earth is going around 0:04:16.279 --> 0:04:19.719 the Sun, not the Sun and everything else going around 0:04:19.760 --> 0:04:24.160 the Earth. And there that caused a bit of a debate, 0:04:24.560 --> 0:04:28.320 I would say, in philosophical circles. Um. Yeah, And then 0:04:28.400 --> 0:04:33.080 you get a fellow named Giordano Bruno who back in 0:04:34.360 --> 0:04:37.599 proposed that other stars might have planets of their own, 0:04:37.720 --> 0:04:42.000 just like our Sun has planets orbiting it. Uh. There 0:04:42.000 --> 0:04:45.599 were some people who disagreed with Bruno. They they took 0:04:45.680 --> 0:04:48.520 issue with what he had to say. It was the 0:04:48.600 --> 0:04:52.000 Roman Catholic Church at the time, and the way they 0:04:52.080 --> 0:04:57.120 expressed their dissenting this discending opinion was by burning him 0:04:57.120 --> 0:05:02.400 at the stake. So Bruno paid for his his belief, 0:05:02.600 --> 0:05:06.239 which turned out to be true with his life. Yeah, 0:05:06.279 --> 0:05:08.840 people were even harsher back than than they are in 0:05:09.120 --> 0:05:11.720 YouTube comments. Yeah, it's about to say it does bring 0:05:11.760 --> 0:05:16.360 a little perspective, but you know, figuratively speaking, YouTube commoners 0:05:16.360 --> 0:05:18.240 are pretty much doing the same thing to us. But 0:05:18.440 --> 0:05:22.920 figuratively alright, So at any rate, that was sort of 0:05:22.960 --> 0:05:25.040 the the If you want to look at the earliest 0:05:25.760 --> 0:05:29.560 thinkers who were putting forth this idea of other stars 0:05:29.600 --> 0:05:32.960 having planets orbiting around them, those would be the earliest 0:05:32.960 --> 0:05:35.680 ones I would point to. But these days we actually 0:05:35.720 --> 0:05:40.120 have direct evidence of planets orbiting other stars. We don't 0:05:40.200 --> 0:05:43.120 have to guess anymore. We can actually use the instruments 0:05:43.160 --> 0:05:46.080 of astronomy we've created to get data that tell us 0:05:46.120 --> 0:05:49.040 there must be other planets out there like us. And 0:05:49.120 --> 0:05:52.839 this isn't just a matter of pure curiosity. It actually 0:05:52.960 --> 0:05:56.400 bears on many other questions and science and maybe even 0:05:56.440 --> 0:06:00.200 the future of what happens to the human race. Sure, now, 0:06:00.240 --> 0:06:03.440 of course, the pure science element does matter a lot, because, 0:06:03.800 --> 0:06:06.520 as with every question in science, we can never really 0:06:06.600 --> 0:06:11.360 know how a piece of information, once gathered, might be used. Yeah, 0:06:11.800 --> 0:06:15.159 something that we know about astronomy about exceplants may prove 0:06:15.240 --> 0:06:17.440 useful in the future in ways that we don't imagine 0:06:17.520 --> 0:06:19.800 right now, even if that just means that we get 0:06:19.839 --> 0:06:23.040 a better understanding of how our universe works, which you know, 0:06:23.400 --> 0:06:27.080 some people dismiss, but that's that's just really cool. The 0:06:27.160 --> 0:06:30.040 idea that we learn things new things about how planets 0:06:30.040 --> 0:06:33.000 are formed and how how they uh you know, orbit 0:06:33.040 --> 0:06:36.440 their stars and what kind of different bodies they can orbit, 0:06:36.720 --> 0:06:39.760 or or what kind of planets are the most common, 0:06:39.800 --> 0:06:42.360 like how unusual a situation like Earth is, or how 0:06:42.400 --> 0:06:44.960 many gas giants there are, or how big or small 0:06:45.000 --> 0:06:48.200 many planets are. Yeah, yeah, very good questions. The other 0:06:48.279 --> 0:06:50.920 thing you might want to consider is how about Earth too? 0:06:51.360 --> 0:06:54.560 How about Earth too? Well. One thing you might observe 0:06:54.720 --> 0:06:57.920 looking at us in our environment is that the population 0:06:57.960 --> 0:07:00.960 of humans on the planet is consistently growing, but the 0:07:01.040 --> 0:07:04.160 planet is not getting any bigger and its resources are 0:07:04.160 --> 0:07:07.279 not multiplying. There may come a day when, in order 0:07:07.320 --> 0:07:10.680 to continue growing, the human species needs to expand beyond 0:07:10.720 --> 0:07:14.920 the planet Earth, uh well, especially to continue growing, growing 0:07:14.960 --> 0:07:17.120 in a way that's comfortable and healthy for all of us. 0:07:17.640 --> 0:07:20.120 In other words, we have to have another place to go. Yeah, 0:07:20.120 --> 0:07:22.680 And so you might look at planets in our own 0:07:22.720 --> 0:07:26.360 solar system and terror forming colonization, or you might look 0:07:26.440 --> 0:07:29.560 way beyond and say, well, is there possibility we could 0:07:29.600 --> 0:07:34.200 colonize extra solar planets planets in other solar systems throughout 0:07:34.240 --> 0:07:36.280 the galaxy? It might be more worthwhile to take a 0:07:36.280 --> 0:07:38.200 little bit of a road trip to someplace that's a 0:07:38.200 --> 0:07:41.520 lot more habitable. Yeah, maybe, depending on how fast we 0:07:41.560 --> 0:07:43.760 can get there. Well, And that's a question I think 0:07:43.760 --> 0:07:45.960 we'll look into towards the end of this podcast. But 0:07:46.360 --> 0:07:49.120 another one of the big questions that exoplanets bear on 0:07:49.240 --> 0:07:53.920 is the question of astrobiology extraterrestrial life, Right, what other 0:07:54.080 --> 0:07:56.960 life is out there beyond Earth? Is it Earth like? 0:07:57.520 --> 0:08:01.480 Is it very different from Earth life? That we we 0:08:01.600 --> 0:08:04.600 have a sample size of one planet. When it comes 0:08:04.680 --> 0:08:07.920 to life, we have no way of knowing if what 0:08:08.320 --> 0:08:12.320 we think of his life as representative of the entire galaxy, 0:08:12.400 --> 0:08:16.920 let alone the universe. So this would be a huge 0:08:17.000 --> 0:08:19.920 thing to be able to look at another planet and 0:08:20.000 --> 0:08:23.960 determine what are the what's the likelihood of life being 0:08:24.000 --> 0:08:28.600 found there? Right? I mean, just the discovery of other 0:08:28.680 --> 0:08:32.400 planets out there in the habitable zones around stars is 0:08:32.760 --> 0:08:36.000 already bearing on certain things like the question of the 0:08:36.000 --> 0:08:39.480 Fermi paradox. You've got that Drake equation we talked about. 0:08:39.520 --> 0:08:41.679 We did a podcast back. If you're not familiar, you 0:08:41.720 --> 0:08:44.200 can go check that out our podcast on the Drake equation. 0:08:44.240 --> 0:08:47.280 But it's the question of why aren't we hearing any 0:08:47.320 --> 0:08:51.760 signals from alien civilizations? Um, what's the thing that's limiting 0:08:51.840 --> 0:08:55.080 the number of alien civilizations out there? And it used 0:08:55.080 --> 0:08:57.400 to be thought that, well, maybe there just aren't enough 0:08:57.480 --> 0:09:00.880 planets in our galaxy on which alien life could arise. 0:09:00.920 --> 0:09:04.559 We now know that that variable is smashed. There are 0:09:04.640 --> 0:09:08.160 tons of planets out there, so we're actually narrowing down 0:09:08.200 --> 0:09:10.320 the question. It's got to be one of these other 0:09:10.480 --> 0:09:13.600 variables limiting the number of aliens that could be talking 0:09:13.640 --> 0:09:16.320 to us but aren't. And why do we know we 0:09:16.360 --> 0:09:18.400 need to look at planets? Well, I think we can 0:09:18.400 --> 0:09:20.640 make a pretty good guess based on physics that we're 0:09:20.679 --> 0:09:24.400 not going to find life forms in stars, not life 0:09:24.440 --> 0:09:26.600 as we know it at any rate. Yeah, where we're 0:09:26.640 --> 0:09:29.600 going to need something more or less Earth temperature. You know, 0:09:29.679 --> 0:09:31.720 water would need to be in a liquid state at 0:09:31.760 --> 0:09:34.880 least at some point during its cycle. Yeah, it's yeah, 0:09:34.880 --> 0:09:38.000 it's hard to imagine any kind of complex system like 0:09:38.120 --> 0:09:40.720 a life form existing at a temperature that a star 0:09:40.800 --> 0:09:43.920 would operate at. Yeah, I wouldn't do well in it. 0:09:45.480 --> 0:09:48.360 So let's take a look at some actual discoveries of 0:09:48.400 --> 0:09:50.400 exo planets. I want to know when was the first 0:09:50.400 --> 0:09:54.160 exo planet really actually discovered by science? All right, well, 0:09:54.200 --> 0:09:57.439 if you're looking for the first time someone pointed at 0:09:57.640 --> 0:10:02.079 at data and said, we can be definitively sure that 0:10:02.120 --> 0:10:06.480 this is coming from other planets outside of our Solar system. 0:10:06.520 --> 0:10:09.080 You know, it was just twenty years ago when we 0:10:09.520 --> 0:10:13.120 saw someone point and say, this is definitive proof that 0:10:13.160 --> 0:10:18.760 there is at least one, probably multiple planets outside of 0:10:18.760 --> 0:10:20.960 our own Solar system, and here's the data to prove it. 0:10:21.200 --> 0:10:23.200 It was a radio astronomer who discovered it back in 0:10:24.880 --> 0:10:27.920 and uh he detected two or three planet sized objects 0:10:27.920 --> 0:10:31.200 in orbit around a pulsar in the Virgo constellation. So 0:10:31.280 --> 0:10:33.959 not a star but a pulsar, which is the remnants 0:10:34.040 --> 0:10:37.240 after a supernova, so kind of interesting. It actually got 0:10:37.280 --> 0:10:40.280 some people grumbling about how it shouldn't count because the 0:10:40.320 --> 0:10:44.200 exo planets were in an orbit around the star, but um, uh, 0:10:44.360 --> 0:10:47.600 the data was from the radio telescopes he was using, 0:10:48.120 --> 0:10:52.720 and uh he was detecting, uh, the the effects of 0:10:52.800 --> 0:10:56.720 gravitational force of multiple large bodies upon that pulsar, which 0:10:57.160 --> 0:11:00.760 was what allowed him to infer that there were planets 0:11:00.880 --> 0:11:03.920 or around. Yeah, and we'll talk more about that kind 0:11:03.920 --> 0:11:07.120 of way of detecting planets in a little bit now. 0:11:07.120 --> 0:11:09.480 The first discovery of an exo plant that was actually 0:11:09.480 --> 0:11:14.480 an orbit around a star. Yeah, this dates so just 0:11:14.559 --> 0:11:16.560 one year later, and it was a pair of Swiss 0:11:16.559 --> 0:11:19.760 scientists who announced the discovery of a plant somewhere between 0:11:20.080 --> 0:11:22.800 half the size of Jupiter and two times the size 0:11:22.800 --> 0:11:26.880 of Jupiter. That's it's actually pretty tiny for for exit planets. 0:11:27.000 --> 0:11:29.800 It's also it's also uh, you know, it sounds like 0:11:29.960 --> 0:11:34.800 a huge range, but really when you're talking about galactic measures. 0:11:35.280 --> 0:11:40.839 It's so they determined that was an extremely close orbit 0:11:40.880 --> 0:11:44.800 around its parents star, which was fifty one pegasi, and 0:11:44.880 --> 0:11:48.840 its year was really really short. It's year lasts four 0:11:48.960 --> 0:11:53.160 point to earth days, so every every four point two 0:11:53.240 --> 0:11:56.760 days it orbits its Sun. Feels like it feels like 0:11:56.760 --> 0:11:59.360 a whole lot of whiplash. To me, how many years 0:11:59.360 --> 0:12:03.400 old would you? Why did you ask me that question? 0:12:03.440 --> 0:12:05.599 I would have I would have actually done the calculations 0:12:05.640 --> 0:12:10.280 that I thought about it. Um, I'm almost I'm almost. No, 0:12:10.360 --> 0:12:13.440 I'm not gonna do it. If I try and do 0:12:13.480 --> 0:12:16.160 the math, that will just come out horribly wrong. Well, anyway, 0:12:16.280 --> 0:12:20.320 they had discovered the presence of this planet again through 0:12:20.440 --> 0:12:25.679 indirect observation. They used radial velocity detection, which will also 0:12:25.800 --> 0:12:28.360 kind of talk about in a little bit. And soon, 0:12:28.679 --> 0:12:32.920 because they showed that this method was uh you know, 0:12:33.320 --> 0:12:37.040 it was a working method, soon the discoveries just started 0:12:37.080 --> 0:12:40.400 coming pretty quickly. Now, at first, like a lot. If 0:12:40.440 --> 0:12:43.199 you look back at the history of exoplanet discoveries and 0:12:43.240 --> 0:12:46.440 you're looking at stuff from the early two thousand's, they'll 0:12:46.480 --> 0:12:50.079 they'll say, like eight whole planets have been discovered so far. 0:12:50.840 --> 0:12:54.240 But over the next few years, especially once we started 0:12:54.440 --> 0:12:56.600 to really know what to look for and we had 0:12:56.679 --> 0:13:02.920 access to some pretty incredible tools, Uh, that number exploded. Um. Now. 0:13:02.960 --> 0:13:06.640 The first DEDICAD exoplanet space mission was the launch of 0:13:06.679 --> 0:13:11.320 the Corot Space Telescope in two thousand and six, the 0:13:11.360 --> 0:13:15.280 c O R O T, and it provides a continuous 0:13:15.320 --> 0:13:17.840 observation of a stellar field for a period of up 0:13:17.840 --> 0:13:20.360 to six months at a time. So it just it 0:13:20.480 --> 0:13:25.120 just keeps its uh, it's I essentially on a specific 0:13:25.240 --> 0:13:28.120 segment of space and leaves it there for like six 0:13:28.160 --> 0:13:31.480 months to see, you know, any sort of variation in 0:13:31.520 --> 0:13:34.400 the brightness of the stars that are in that stellar field, 0:13:34.720 --> 0:13:39.080 and when it starts to detect variations, it looks for patterns. 0:13:39.120 --> 0:13:41.120 So if you find a pattern in the variation of 0:13:41.120 --> 0:13:43.280 the brightness of a star that suggests that something is 0:13:43.320 --> 0:13:46.559 passing between that star and Earth on a regular basis, 0:13:46.880 --> 0:13:49.880 we'll talk more about that too. So those are kind 0:13:49.880 --> 0:13:53.480 of the early approaches or the early um the early 0:13:53.520 --> 0:13:57.719 examples of this very young field. Well, I think we 0:13:57.760 --> 0:14:00.280 should look at some of the most common methods that 0:14:00.320 --> 0:14:04.760 are used to detect extrasolar planets. Yeah, sure, Well, I 0:14:04.760 --> 0:14:06.760 think the first one we should mention, though it's certainly 0:14:06.800 --> 0:14:09.960 not the most common at this point, is simple direct imaging. 0:14:10.000 --> 0:14:12.839 I think this is what a lot of people would 0:14:12.840 --> 0:14:15.320 just guess is happening. You're just taking a picture up 0:14:15.320 --> 0:14:17.760 in the sky and you see next to a star, 0:14:17.880 --> 0:14:21.280 there's a little planet, a little dot, and there it is. Yeah. 0:14:21.320 --> 0:14:26.000 The problem is that that those dots at that distance 0:14:26.120 --> 0:14:31.840 are saying they're little is being generous, Yeah, that they 0:14:31.920 --> 0:14:36.400 just the typically don't emit enough light that's detectable at 0:14:36.440 --> 0:14:39.880 this distance and distinguishable from the star they orbit to 0:14:40.240 --> 0:14:42.600 see this. This is a problem we have at this point. 0:14:42.640 --> 0:14:46.160 It's really hard to directly image planets. There's there's also 0:14:46.200 --> 0:14:49.320 a lot of glare coming off of well, glare coming 0:14:49.360 --> 0:14:52.800 off of a nearby stars that's going to obscure direct 0:14:52.920 --> 0:14:57.200 visualization of planets like that. Yeah, though it has been done. 0:14:57.280 --> 0:14:59.880 We have card direct images of a few extra so 0:15:00.000 --> 0:15:04.120 the planets with radio waves and with infrared, I believe. 0:15:04.640 --> 0:15:07.560 But there are other methods that are have been used 0:15:07.560 --> 0:15:09.920 a lot more commonly, and one of the main ones 0:15:09.960 --> 0:15:13.280 I want to talk about is the radial velocity method 0:15:13.480 --> 0:15:16.840 is the one I had mentioned earlier with the approach 0:15:16.840 --> 0:15:20.680 with the radio telescope. Yea so true or false question 0:15:21.000 --> 0:15:23.280 t r F question for you, And you can't just 0:15:23.360 --> 0:15:25.840 draw that little thing that could be a T or 0:15:25.880 --> 0:15:29.200 an F, so we have to come down firm the 0:15:29.240 --> 0:15:32.880 whole word. Okay, true or false? The Sun is stationary, 0:15:32.920 --> 0:15:36.880 the unmoving center of gravity in our solar system. That well, 0:15:36.960 --> 0:15:39.440 I mean, I know the answer to this, and also 0:15:39.480 --> 0:15:41.600 it's in our notes, so it would be cheating. But 0:15:41.600 --> 0:15:43.760 would you would you like me to play along? Play along. 0:15:43.920 --> 0:15:46.400 I think that's true, Joe. Well, it's true. We do 0:15:46.480 --> 0:15:49.160 go around the Sun. Except it's false because the Sun 0:15:49.280 --> 0:15:52.080 is not stationary. Wait, it's both true and false. You 0:15:52.200 --> 0:15:56.360 tricked me, Because in space it actually isn't the case 0:15:56.440 --> 0:16:00.280 that a bigger object pulls a smaller object. It's the 0:16:00.280 --> 0:16:04.040 case that both objects pull each other. Yeah, the force 0:16:04.080 --> 0:16:07.800 of gravity exerts on both, on both masses. Right, So 0:16:07.840 --> 0:16:11.280 when you have two objects, it may look from one 0:16:11.280 --> 0:16:16.200 perspective that, say, Jupiter is orbiting the Sun, but in fact, 0:16:16.280 --> 0:16:19.320 both Jupiter and the Sun are orbiting the center of 0:16:19.440 --> 0:16:23.400 gravity between Jupiter and the Sun. And because the Sun 0:16:23.760 --> 0:16:26.960 is so much bigger than Jupiter, the way this typically 0:16:27.080 --> 0:16:29.240 looks is just that Jupiter is going around the Sun, right, 0:16:29.280 --> 0:16:32.880 because the Sun's size actually overlaps that edge of the 0:16:32.920 --> 0:16:38.520 center of the gravitational Furthermore, I mean the entire Solar 0:16:38.560 --> 0:16:41.400 system is moving um and our entire galaxy is moving 0:16:41.680 --> 0:16:44.120 right right, So there are several ways in which the 0:16:44.160 --> 0:16:47.280 Sun is moving. Yes, but it actually does move in 0:16:47.360 --> 0:16:50.520 response to the gravity exerted on it by its planets, 0:16:51.080 --> 0:16:54.040 And an outside observer could look in on this and 0:16:54.120 --> 0:16:57.120 notice it, especially in response to the big planets like 0:16:57.200 --> 0:16:59.880 Jupiter and Saturn. The effect is that the sun or 0:16:59.920 --> 0:17:03.640 the star seems to wobble. Yeah, it actually appears to 0:17:03.680 --> 0:17:06.840 be moving in relation to those plants. And if you're 0:17:06.880 --> 0:17:08.720 far enough out where you can't see the planets but 0:17:08.800 --> 0:17:11.240 you can see the star, you'll see that the star 0:17:11.520 --> 0:17:13.640 is wiggling a little bit, since it's doing a little 0:17:13.640 --> 0:17:16.159 bit of a chimmy. Yeah. Right, So the same is 0:17:16.200 --> 0:17:20.080 true in other solar systems throughout the galaxy. But how 0:17:20.080 --> 0:17:22.879 would we detect if a star that's dozens of light 0:17:22.960 --> 0:17:26.760 years away is just wobbling slightly in response to the 0:17:26.760 --> 0:17:29.480 gravitational pull of a planet like it would just seem 0:17:29.520 --> 0:17:31.560 like it's a pin prick. And how could you ever 0:17:31.640 --> 0:17:33.639 be sure that what you saw was a wobble and 0:17:33.720 --> 0:17:37.680 not say the fault of your instrumentation? Right, Well, you 0:17:37.760 --> 0:17:41.320 can measure it with the Doppler effect. Now we should 0:17:41.320 --> 0:17:44.879 probably explain what the Doppler effect is. Okay, so you 0:17:44.880 --> 0:17:47.560 you may remember this from physics class in high school. 0:17:47.880 --> 0:17:53.160 Any object emitting waves, which I love objects that emit waves. There, 0:17:54.280 --> 0:17:58.399 whenever something emits waves, it seems to produce higher frequency 0:17:58.440 --> 0:18:02.399 waves when it's moving towards you and lower frequency waves 0:18:02.400 --> 0:18:04.359 when it's moving away from you. And if you just 0:18:04.480 --> 0:18:06.600 picture the waves in your head, you can kind of 0:18:06.600 --> 0:18:09.080 see why this is the case. Something coming towards you 0:18:09.520 --> 0:18:12.640 is compressing the waves as it moves in your direction. 0:18:13.119 --> 0:18:15.640 Something moving away from you is stretching the waves out 0:18:15.680 --> 0:18:17.760 as it moves away. So this would be if you 0:18:17.800 --> 0:18:20.680 ever hear you know, cars going by you where they're 0:18:20.680 --> 0:18:25.640 honking the horn. You're exactly right. Yeah, the passing police 0:18:25.640 --> 0:18:28.959 car is the classic example. The sirens higher pitched as 0:18:28.960 --> 0:18:32.480 it's coming your direction after it passes by, exactly right. 0:18:32.640 --> 0:18:35.400 This is also true with light. It's not just now 0:18:35.520 --> 0:18:40.000 you know, sound is a physical acoustic wave, but electromagnetic 0:18:40.080 --> 0:18:43.840 radiation the same thing. The same principle applies. Yeah, so 0:18:44.160 --> 0:18:47.199 you can have the police radar gun. The police officer 0:18:47.280 --> 0:18:50.679 can clock the velocity of an approaching or receding vehicle 0:18:50.760 --> 0:18:54.080 by bouncing radio waves. I think it's usually microwaves off 0:18:54.080 --> 0:18:57.000 the car, so it shoots the gun, bounces the waves back, 0:18:57.400 --> 0:19:00.359 and then by calculating the difference between the outgoing waves 0:19:00.359 --> 0:19:03.240 and the waves coming back, the radar gun can detect 0:19:03.240 --> 0:19:06.639 the speed of the car. But this also works for 0:19:06.680 --> 0:19:11.160 electromagnetic waves produced by distant stars. So as the star 0:19:11.320 --> 0:19:15.280 wobbles away from us because of another object in the system, 0:19:15.520 --> 0:19:19.240 the radiation signature changes to a lower frequency, the red shift. 0:19:19.640 --> 0:19:21.560 You may have heard of this, And then when it 0:19:21.560 --> 0:19:25.000 wobbles back towards us again, the radiation signature is shifted 0:19:25.080 --> 0:19:28.880 up towards the blue frequency, the blue shift. So by 0:19:28.880 --> 0:19:32.119 studying the pattern of how the star wobbles, astronomers can 0:19:32.160 --> 0:19:34.639 actually learn a whole lot about the planet that's causing 0:19:34.680 --> 0:19:37.520 the wobbling, including a pretty good guess at its mass. 0:19:38.119 --> 0:19:41.119 But there are limitations to this kind of thing because 0:19:41.160 --> 0:19:45.040 the method depends on the gravitational poll exerted by the planet. 0:19:45.320 --> 0:19:49.600 It's best at finding relatively high mass planets closely orbiting 0:19:49.640 --> 0:19:53.520 relatively low mass stars. You remember that gravity is dependent 0:19:53.600 --> 0:19:56.240 upon two things. It's depending upon the mass of the 0:19:56.320 --> 0:20:00.119 objects in question and the distance between them. So the 0:20:00.160 --> 0:20:02.960 closer and the more massive the objects are, the more 0:20:02.960 --> 0:20:06.360 detectable this would be. Yeah, So what kind of tools 0:20:06.400 --> 0:20:09.160 our researchers using to detect this sort of thing? Essentially 0:20:09.160 --> 0:20:13.560 we're using telescopes and spectrometers. Now, a spectrometer it does 0:20:13.600 --> 0:20:16.920 is it separates the light that comes from stars into 0:20:17.000 --> 0:20:20.760 its component colors and then detect the subtle changes even 0:20:20.840 --> 0:20:26.199 when those changes are indistinguishable too. We puny mirror mortals, right, 0:20:26.240 --> 0:20:30.240 so it can detect with high precision the light frequency 0:20:30.320 --> 0:20:32.920 and how that changes as the star wobbles. In fact, 0:20:33.000 --> 0:20:36.800 there's another method that basically tracks the same effect, but 0:20:36.920 --> 0:20:40.359 in a different way. This is called astrometry. This actually 0:20:40.520 --> 0:20:42.919 dates if you're looking at the earliest of the astrometry, 0:20:42.920 --> 0:20:46.199 it dates to like nineteenth century. This is much older, 0:20:46.240 --> 0:20:49.320 and I think generally considered not not as accurate at 0:20:49.359 --> 0:20:52.800 this point. It's we we've mostly moved on to the 0:20:52.880 --> 0:20:56.440 radio velocity and to another one, but interestingly it may 0:20:56.520 --> 0:20:59.840 come back. Yeah, but I'm sorry I should say what 0:20:59.880 --> 0:21:03.320 it is. It's a way of looking for the same 0:21:03.359 --> 0:21:08.080 wobbling of planets visually. Essentially, you just look at where 0:21:08.080 --> 0:21:10.760 a star is in relation to the other stars around it, 0:21:11.040 --> 0:21:15.000 and you visually track its movement over long periods of time. 0:21:15.359 --> 0:21:17.240 As you can guess from the sound of it. That's 0:21:17.240 --> 0:21:19.960 hard to do. Yes, that sounds like you would need 0:21:20.080 --> 0:21:23.320 a really big telescope and a really high res camera 0:21:23.440 --> 0:21:26.400 in order to work that out. Yeah, I'm sure, I'm sure, 0:21:26.400 --> 0:21:30.520 photography made this a lot easier than it was before, 0:21:30.760 --> 0:21:32.240 you know, when you just had to kind of look 0:21:32.280 --> 0:21:36.320 at it and seeing, yeah, that's that's a half a degree, 0:21:37.240 --> 0:21:41.479 it's a scoch. But then there's another one where you 0:21:41.520 --> 0:21:44.800 can try to infer something about planets just by looking 0:21:44.800 --> 0:21:48.000 at the star itself. And this is probably the one 0:21:48.040 --> 0:21:50.280 that's on the rise, the one that just recently got 0:21:50.280 --> 0:21:53.320 really big, the transit method. Yeah, this is where you're 0:21:53.320 --> 0:21:55.320 looking at the light that's coming from the star and 0:21:55.359 --> 0:21:57.200 you're looking for any sort of dimming that would be 0:21:57.280 --> 0:22:00.920 indicative of a body passing between the Earth and that star. 0:22:01.200 --> 0:22:03.840 All right, a little bit like observing a solar eclipse 0:22:03.880 --> 0:22:06.240 here on Earth, where the moon is passing between you 0:22:06.359 --> 0:22:09.040 and the sun, right, except on of course, obviously on 0:22:09.080 --> 0:22:13.160 a much smaller scale because the distance is involved, uh, 0:22:13.200 --> 0:22:15.800 and and our perspective. But the idea is that we 0:22:15.800 --> 0:22:18.879 would use very precise instrumentation to measure the amount of 0:22:18.920 --> 0:22:22.200 light that's coming from a star and looking for those 0:22:22.200 --> 0:22:26.399 sort of patterns that you see a one percent dip 0:22:26.440 --> 0:22:29.760 in the luminosity of a star at certain regular intervals 0:22:30.160 --> 0:22:33.400 that could be indicative of an an orbiting body going 0:22:33.440 --> 0:22:36.720 around that start blocking some of the light. Now, obviously 0:22:36.880 --> 0:22:40.919 this depends on lots of different factors. The precision of 0:22:40.920 --> 0:22:43.159 your instrumentation is a big one, but another one is 0:22:43.200 --> 0:22:47.800 just the alignment of the planet's orbit around that star 0:22:48.080 --> 0:22:52.720 compared to where we on Earth are. Because despite what 0:22:53.000 --> 0:22:56.359 most science fiction films would have you believe, space in 0:22:56.400 --> 0:22:58.400 fact has lots of different ways that you can come 0:22:58.400 --> 0:23:01.760 at different objects. And you're not always just nos two 0:23:01.760 --> 0:23:05.320 nose in your spaceship with the other spaceships. Sometimes you're 0:23:05.359 --> 0:23:08.080 all catty wumpus with each other. Like, like we said, 0:23:08.480 --> 0:23:12.639