1 00:00:04,440 --> 00:00:12,280 Speaker 1: Welcome to tech Stuff, a production from iHeartRadio. Hey there, 2 00:00:12,320 --> 00:00:15,320 Speaker 1: and welcome to tech Stuff. I'm your host Jonathan Strickland. 3 00:00:15,360 --> 00:00:19,080 Speaker 1: I'm an executive producer with iHeartRadio and how the tech 4 00:00:19,200 --> 00:00:23,080 Speaker 1: are you? It is time for a classic episode of 5 00:00:23,400 --> 00:00:28,680 Speaker 1: tech Stuff. This episode is titled How the Kepler Telescope Works, 6 00:00:28,960 --> 00:00:34,960 Speaker 1: and it published on June eighth, twenty sixteen, Enjoy. In 7 00:00:35,000 --> 00:00:38,840 Speaker 1: May twenty sixteen, researchers with the Kepler Mission at NASA 8 00:00:38,920 --> 00:00:41,320 Speaker 1: held a press conference in which they announced the largest 9 00:00:41,440 --> 00:00:46,919 Speaker 1: number of exoplanets verified ever at a single event, and 10 00:00:46,960 --> 00:00:52,440 Speaker 1: that was one thy two hundred and eighty four verified exoplanets. Previously, 11 00:00:52,880 --> 00:00:55,279 Speaker 1: from two thousand and nine, up to that point, the 12 00:00:55,280 --> 00:00:59,080 Speaker 1: mission had identified and verified nine hundred eighty four planets. 13 00:00:59,320 --> 00:01:02,200 Speaker 1: So this is announcement was more than doubling the number 14 00:01:02,320 --> 00:01:07,760 Speaker 1: of exoplanets verified. That's incredible. So an exoplanet, just in 15 00:01:07,760 --> 00:01:09,560 Speaker 1: case you don't know, is of course a planet that 16 00:01:09,640 --> 00:01:13,560 Speaker 1: is orbiting another star, not the Sun. So it's planets 17 00:01:13,600 --> 00:01:18,520 Speaker 1: in other star systems, solar systems that are light years 18 00:01:18,520 --> 00:01:22,000 Speaker 1: away from us. And it was a really cool thing 19 00:01:22,120 --> 00:01:25,560 Speaker 1: to hear about all these different exoplanets that had just 20 00:01:25,600 --> 00:01:30,200 Speaker 1: been verified. What I thought was hilarious was leading up 21 00:01:30,240 --> 00:01:35,679 Speaker 1: to this announcement, you had several news outlets that were 22 00:01:37,200 --> 00:01:39,760 Speaker 1: guessing what was going to happen. It was just it 23 00:01:39,800 --> 00:01:42,960 Speaker 1: was just complete throw stuff against the wall and see 24 00:01:42,959 --> 00:01:45,520 Speaker 1: what sticks. And there were quite a few that had 25 00:01:45,560 --> 00:01:49,800 Speaker 1: guessed that NASA was going to announce that the Kepler 26 00:01:49,840 --> 00:01:54,400 Speaker 1: mission had somehow discovered alien life. Now, once you hear 27 00:01:54,440 --> 00:01:57,240 Speaker 1: how the Kepler telescope works and what it's meant to do, 28 00:01:57,320 --> 00:02:01,480 Speaker 1: you'll understand that's really not in the purview of the 29 00:02:01,560 --> 00:02:04,960 Speaker 1: Kepler telescope. It is looking for planets that could potentially 30 00:02:05,000 --> 00:02:09,760 Speaker 1: support life, but it doesn't have the capacity to actually 31 00:02:09,800 --> 00:02:14,440 Speaker 1: detect life on those other planets unless someone sent aliens 32 00:02:14,440 --> 00:02:17,160 Speaker 1: to Earth and they started messing with the Kepler telescope, 33 00:02:17,200 --> 00:02:19,840 Speaker 1: in which case you could say it discovered life, but 34 00:02:20,040 --> 00:02:23,840 Speaker 1: not through its primary mission. That did not happen. As 35 00:02:23,840 --> 00:02:26,640 Speaker 1: far as I know, no aliens have been messing with 36 00:02:26,639 --> 00:02:32,480 Speaker 1: the Kepler telescope. So let's talk about how this telescope 37 00:02:32,520 --> 00:02:36,760 Speaker 1: works and this new verification method that the research team 38 00:02:36,840 --> 00:02:40,520 Speaker 1: used to identify so many exoplanets. What was it that 39 00:02:40,840 --> 00:02:44,200 Speaker 1: sped up the process so dramatically as to more than 40 00:02:44,320 --> 00:02:48,680 Speaker 1: double the number of confirmed exoplanets. Plus i'll talk a 41 00:02:48,680 --> 00:02:51,519 Speaker 1: little bit about the new candidates for Earth like planets 42 00:02:51,600 --> 00:02:55,720 Speaker 1: that might be capable of supporting life. So first, let's 43 00:02:55,720 --> 00:03:00,720 Speaker 1: go way back. The Kepler Telescope is named after Johann Kepler, 44 00:03:01,120 --> 00:03:04,880 Speaker 1: an astronomer of the late sixteenth and early seventeenth centuries. 45 00:03:05,360 --> 00:03:07,520 Speaker 1: That's not the original name of the telescope, by the way, 46 00:03:07,560 --> 00:03:10,000 Speaker 1: but more on that in a little bit. So Johann 47 00:03:10,080 --> 00:03:13,440 Speaker 1: Kepler is most famous for discovering the three major laws 48 00:03:13,440 --> 00:03:16,440 Speaker 1: of planetary motion, although at the time no one called 49 00:03:16,480 --> 00:03:20,800 Speaker 1: them laws. It would take Newton and Newton's observations before 50 00:03:20,840 --> 00:03:25,200 Speaker 1: that really started to become a thing. But law number 51 00:03:25,280 --> 00:03:29,079 Speaker 1: one is that the planets move in elliptical orbits around 52 00:03:29,120 --> 00:03:31,720 Speaker 1: the Sun. Law number two, the time it takes to 53 00:03:31,800 --> 00:03:36,040 Speaker 1: traverse any arc of a planetary orbit is proportional to 54 00:03:36,080 --> 00:03:39,800 Speaker 1: the area of the sector between the central body, for example, 55 00:03:40,000 --> 00:03:42,920 Speaker 1: the Sun and the arc. So you can think of 56 00:03:42,960 --> 00:03:45,360 Speaker 1: the two points along the ark, the starting point and 57 00:03:45,360 --> 00:03:49,320 Speaker 1: the endpoint of the arc as your barriers on one side, 58 00:03:49,720 --> 00:03:53,720 Speaker 1: the Sun being the third point in what's not exactly 59 00:03:53,760 --> 00:03:56,160 Speaker 1: a triangle because you have a curve line a straight 60 00:03:56,200 --> 00:03:59,880 Speaker 1: line on the arc side the area within that that 61 00:04:00,200 --> 00:04:05,680 Speaker 1: is proportional to the time it takes to traverse that arc. Essentially, 62 00:04:05,760 --> 00:04:08,320 Speaker 1: what that tells you is that the further out you 63 00:04:08,360 --> 00:04:11,480 Speaker 1: are from a star, the slower your orbit is going 64 00:04:11,560 --> 00:04:15,040 Speaker 1: to be, and the closer en you are to a star, 65 00:04:15,120 --> 00:04:18,839 Speaker 1: the faster your orbit is going to be. Also, there's 66 00:04:18,839 --> 00:04:22,400 Speaker 1: a relationship between the square of a planet's periodic time 67 00:04:22,600 --> 00:04:25,400 Speaker 1: and the cube of the radius of its orbit, which 68 00:04:25,440 --> 00:04:29,840 Speaker 1: is also known as the harmonic law. That's law number three. Now, 69 00:04:29,880 --> 00:04:33,120 Speaker 1: the Kepler mission all started out with a question, which 70 00:04:33,200 --> 00:04:36,880 Speaker 1: was how frequent are other Earth sized planets in our 71 00:04:36,960 --> 00:04:41,480 Speaker 1: galaxy the Milky Way? How common is that? Is the 72 00:04:41,520 --> 00:04:46,520 Speaker 1: Earth a strange outlier that is one in a billion 73 00:04:46,760 --> 00:04:50,480 Speaker 1: or one in ten billion, or even more rare than 74 00:04:50,520 --> 00:04:53,719 Speaker 1: that We had no way of knowing. Now, that particular 75 00:04:53,800 --> 00:04:57,479 Speaker 1: space based telescope, the Kepler telescope, tries to answer this 76 00:04:57,600 --> 00:05:03,280 Speaker 1: question by looking for planets what is called the transit method. Now, 77 00:05:03,360 --> 00:05:07,520 Speaker 1: this method was proposed a few times leading up to 78 00:05:07,760 --> 00:05:13,279 Speaker 1: nineteen seventy one, when Frank Rosenblatt really went strong with 79 00:05:13,360 --> 00:05:16,599 Speaker 1: the idea. He suggested the transit method for detecting satellites 80 00:05:16,720 --> 00:05:20,960 Speaker 1: orbiting other stars. And technically, the way this works is 81 00:05:20,960 --> 00:05:23,479 Speaker 1: that you look at a star and you measure the 82 00:05:23,520 --> 00:05:26,640 Speaker 1: amount of light coming to Earth from that star, and 83 00:05:26,680 --> 00:05:30,720 Speaker 1: you look for any variations and that any dimming of 84 00:05:30,720 --> 00:05:34,960 Speaker 1: that light. Now, if a planet were to pass between 85 00:05:35,120 --> 00:05:38,159 Speaker 1: that star and the Earth, you would expect the light 86 00:05:38,200 --> 00:05:42,640 Speaker 1: from that star to dim a tiny amount, and that 87 00:05:42,680 --> 00:05:45,479 Speaker 1: if you were able to detect that difference, and you 88 00:05:45,520 --> 00:05:49,600 Speaker 1: were able to observe that this happens regularly over the 89 00:05:49,600 --> 00:05:52,400 Speaker 1: course of a given amount of time, you could come 90 00:05:52,440 --> 00:05:55,400 Speaker 1: to the conclusion that what you have seen is in 91 00:05:55,440 --> 00:05:59,880 Speaker 1: fact a planet passing between its host star and the Earth. 92 00:06:00,800 --> 00:06:03,920 Speaker 1: This is what we call transit when we see from 93 00:06:03,960 --> 00:06:10,240 Speaker 1: our perspective a planet crossing its star. Now we're looking 94 00:06:10,279 --> 00:06:13,800 Speaker 1: at the planet making its progress across its star in 95 00:06:13,880 --> 00:06:17,560 Speaker 1: the course of that planet's year. So if it's close 96 00:06:17,640 --> 00:06:20,200 Speaker 1: to the same distance from its host star as the 97 00:06:20,240 --> 00:06:23,279 Speaker 1: Earth is from the Sun, you have to wait a 98 00:06:23,279 --> 00:06:27,320 Speaker 1: long time to verify that that in fact is what 99 00:06:27,360 --> 00:06:30,840 Speaker 1: you saw, especially if you want to truly verify it 100 00:06:30,920 --> 00:06:37,920 Speaker 1: and get a few periodic instances of that dimming, and 101 00:06:37,960 --> 00:06:39,920 Speaker 1: if it has if it's a start that has multiple 102 00:06:40,640 --> 00:06:44,479 Speaker 1: planets alone that same orbital plane, then that's going to 103 00:06:44,520 --> 00:06:49,080 Speaker 1: cause some confusion too. But by seeing the amount of 104 00:06:49,200 --> 00:06:52,760 Speaker 1: light that has been dimmed, and by detecting how long 105 00:06:52,800 --> 00:06:57,800 Speaker 1: it takes this dimming to change back to normal, you 106 00:06:57,839 --> 00:07:01,800 Speaker 1: can start to make some conclusion like how big the 107 00:07:01,839 --> 00:07:05,200 Speaker 1: planet must be, how quickly it travels tells you a 108 00:07:05,200 --> 00:07:08,520 Speaker 1: bit about its orbit. It tells you also by that orbit, 109 00:07:08,640 --> 00:07:11,680 Speaker 1: how close it is to its home star. As long 110 00:07:11,680 --> 00:07:13,840 Speaker 1: as you know information about the home star, then you 111 00:07:13,880 --> 00:07:16,840 Speaker 1: can start to make guesses as to how hot the 112 00:07:16,880 --> 00:07:20,840 Speaker 1: planet is or how cold it might be, And this 113 00:07:20,880 --> 00:07:24,240 Speaker 1: is how you start to draw some conclusions about the 114 00:07:24,320 --> 00:07:28,800 Speaker 1: nature of that planet. Ultimately looking for planets that are 115 00:07:28,920 --> 00:07:34,000 Speaker 1: similar to size, similar to Earth size, i should say, 116 00:07:34,600 --> 00:07:37,160 Speaker 1: and similar to distance from its host star as the 117 00:07:37,200 --> 00:07:39,960 Speaker 1: Earth is to the Sun. The reason for that is 118 00:07:40,000 --> 00:07:45,040 Speaker 1: we know that if the planet is about two times 119 00:07:45,040 --> 00:07:48,240 Speaker 1: the size of Earth or smaller, it's probably going to 120 00:07:48,280 --> 00:07:54,440 Speaker 1: have gravity that is amenable to life as we know it. 121 00:07:54,440 --> 00:07:57,320 Speaker 1: It's going to probably be a rocky planet as opposed 122 00:07:57,360 --> 00:08:00,760 Speaker 1: to a gas giant. That's also important. It's probably going 123 00:08:00,840 --> 00:08:03,800 Speaker 1: to be at a temperature that will allow liquid water 124 00:08:04,440 --> 00:08:06,880 Speaker 1: to be on the planet, and since life as we 125 00:08:07,000 --> 00:08:10,760 Speaker 1: know it depends upon the presence of liquid water, that's 126 00:08:10,760 --> 00:08:12,840 Speaker 1: what we're looking for. Keeping in mind that there is 127 00:08:12,840 --> 00:08:15,240 Speaker 1: the possibility there could be life out there in the 128 00:08:15,280 --> 00:08:19,720 Speaker 1: galaxy that doesn't depend upon liquid water. But we have 129 00:08:19,760 --> 00:08:23,560 Speaker 1: a sample size of one planet with life on it, 130 00:08:23,960 --> 00:08:26,120 Speaker 1: so we have to draw our conclusions based upon the 131 00:08:26,280 --> 00:08:30,880 Speaker 1: limited information we have. So assuming that water is in 132 00:08:30,920 --> 00:08:34,479 Speaker 1: fact necessary for life, we need to find other planets 133 00:08:34,559 --> 00:08:39,240 Speaker 1: that could potentially have water on them. So that's kind 134 00:08:39,240 --> 00:08:45,440 Speaker 1: of guiding the principles behind looking for planets through the 135 00:08:45,480 --> 00:08:51,080 Speaker 1: transit method. But it's really really hard to do. Now, 136 00:08:51,400 --> 00:08:53,920 Speaker 1: let's get back to Frank Rosenblatt for a second. He 137 00:08:54,040 --> 00:08:58,160 Speaker 1: wasn't just famous for suggesting this astronomical approach. He wasn't 138 00:08:58,679 --> 00:09:02,080 Speaker 1: known as a great dronomer. He was actually better known 139 00:09:02,559 --> 00:09:05,640 Speaker 1: as a leading expert in the field of artificial intelligence, 140 00:09:05,720 --> 00:09:12,160 Speaker 1: particularly in the areas of recognizing visual patterns and speech recognition. 141 00:09:12,720 --> 00:09:16,880 Speaker 1: So that was his specific forte. He was really working 142 00:09:16,880 --> 00:09:20,400 Speaker 1: with computers so that they could recognize visual patterns, they 143 00:09:20,400 --> 00:09:23,080 Speaker 1: could recognize when what you are saying when you talk 144 00:09:23,160 --> 00:09:27,439 Speaker 1: to them, and these are fields that today are really 145 00:09:27,440 --> 00:09:30,240 Speaker 1: coming into their own with stuff like Google's Deep Dream, 146 00:09:30,400 --> 00:09:33,600 Speaker 1: where it starts to recognize patterns even if patterns aren't 147 00:09:33,880 --> 00:09:37,400 Speaker 1: really in the picture. It really enhances that and looks 148 00:09:37,440 --> 00:09:40,559 Speaker 1: for patterns in the in ways that are really interesting 149 00:09:40,920 --> 00:09:44,760 Speaker 1: and trippy. And speech recognition, which we're all using to 150 00:09:44,840 --> 00:09:49,280 Speaker 1: some degree these days, often with the personal digital assistants 151 00:09:49,320 --> 00:09:52,079 Speaker 1: that are popping up all over the place. Now here's 152 00:09:52,080 --> 00:09:57,200 Speaker 1: the problem. Rosenblatz suggested approach was not practical at the 153 00:09:57,240 --> 00:10:03,120 Speaker 1: time in the early seventies, the technological sophistication necessary to 154 00:10:03,200 --> 00:10:06,240 Speaker 1: detect and analyze such a very tiny change in a 155 00:10:06,280 --> 00:10:10,760 Speaker 1: star's brightness. If we were looking for an Earth sized 156 00:10:10,880 --> 00:10:15,559 Speaker 1: planet at a distance similar to what Earth is from 157 00:10:15,720 --> 00:10:20,200 Speaker 1: our sun, we're talking about a reduction of one ten 158 00:10:20,360 --> 00:10:23,800 Speaker 1: thousandth the brightness of a star, and that dimming lasts 159 00:10:23,800 --> 00:10:27,960 Speaker 1: between two and sixteen hours, So that's not a lot 160 00:10:27,960 --> 00:10:31,800 Speaker 1: of time, and it's certainly not a big difference in brightness. 161 00:10:31,840 --> 00:10:33,920 Speaker 1: You have to have a very sensitive instrument in order 162 00:10:33,960 --> 00:10:35,760 Speaker 1: to be able to pick that up, and that just 163 00:10:35,800 --> 00:10:39,600 Speaker 1: didn't exist in nineteen seventy one. Now, we also have 164 00:10:39,600 --> 00:10:41,320 Speaker 1: to keep in mind that stars tend to be much 165 00:10:41,440 --> 00:10:44,760 Speaker 1: much bigger than planets. For example, the Sun's diameter is 166 00:10:44,760 --> 00:10:47,320 Speaker 1: one hundred and nine times greater than the Earth's diameter, 167 00:10:47,920 --> 00:10:50,960 Speaker 1: and because of that, that's why with the distance is 168 00:10:51,000 --> 00:10:54,080 Speaker 1: involved and the size is involved, it's such a tiny 169 00:10:54,240 --> 00:10:58,000 Speaker 1: change in the brightness of the star. However, NASA began 170 00:10:58,080 --> 00:11:00,400 Speaker 1: to explore how they might be able to use the 171 00:11:00,440 --> 00:11:05,040 Speaker 1: transit method to detect exoplanets in a practical way. Back 172 00:11:05,080 --> 00:11:07,960 Speaker 1: in nineteen eighty four, they were essentially laying out the 173 00:11:08,000 --> 00:11:12,120 Speaker 1: requirements necessary to detect planets with a reasonable amount of confidence. 174 00:11:12,920 --> 00:11:16,480 Speaker 1: A conference that they held on High precision photometry acted 175 00:11:16,520 --> 00:11:20,960 Speaker 1: as the launching ground figuratively speaking, for discussions about a 176 00:11:21,080 --> 00:11:25,800 Speaker 1: space based telescope designed to detect a transiting planet. The 177 00:11:25,840 --> 00:11:30,640 Speaker 1: idea being that in space there would be less noise 178 00:11:31,080 --> 00:11:34,480 Speaker 1: in the signal to noise ratio, you could get it 179 00:11:34,520 --> 00:11:37,840 Speaker 1: outside the atmosphere. The effects of the atmosphere would not 180 00:11:38,120 --> 00:11:42,440 Speaker 1: be an impediment to a space telescope, and it'd be 181 00:11:42,440 --> 00:11:46,439 Speaker 1: more likely to pick up something as tiny as this 182 00:11:46,600 --> 00:11:50,160 Speaker 1: change in brightness. I'll be back in just a moment 183 00:11:50,200 --> 00:11:53,280 Speaker 1: to talk more about how the Kepler telescope works after 184 00:11:53,320 --> 00:12:06,360 Speaker 1: this quick break, So in nineteen ninety two, NASA proposed 185 00:12:06,400 --> 00:12:08,960 Speaker 1: new missions to look into the possibility of life in 186 00:12:09,000 --> 00:12:11,960 Speaker 1: our galaxy, and the first concept that came up with 187 00:12:12,400 --> 00:12:16,040 Speaker 1: was called the Frequency of Earth Sized Inner Planets or 188 00:12:16,200 --> 00:12:23,600 Speaker 1: FREZIP FRSIP, but that proposal was rejected largely because there 189 00:12:23,679 --> 00:12:26,480 Speaker 1: was doubt at the time that our technological sophistication had 190 00:12:26,520 --> 00:12:30,120 Speaker 1: actually reached a level sufficient to detect any transiting planets 191 00:12:30,120 --> 00:12:33,160 Speaker 1: of Earth like size. So, in other words, if we 192 00:12:33,280 --> 00:12:35,560 Speaker 1: had gone forward with it, we would have built a 193 00:12:35,600 --> 00:12:38,920 Speaker 1: tool that was not up to the task of actually 194 00:12:38,920 --> 00:12:40,760 Speaker 1: doing what was supposed to do, and we would have 195 00:12:40,800 --> 00:12:45,120 Speaker 1: wasted millions of dollars in the process, not something NASA 196 00:12:45,120 --> 00:12:49,000 Speaker 1: could easily afford to do now. Two years later, in 197 00:12:49,080 --> 00:12:53,880 Speaker 1: nineteen ninety four, a team proposed FREZIP again with a 198 00:12:53,960 --> 00:12:58,439 Speaker 1: space based telescope in lagrange orbit, but again a committee 199 00:12:58,440 --> 00:13:00,880 Speaker 1: determined the price would be similar to that of the Hubble, 200 00:13:01,000 --> 00:13:05,200 Speaker 1: which was incredibly expensive and also had been a black 201 00:13:05,320 --> 00:13:09,520 Speaker 1: eye on NASA because when the Hubble launched, it launched 202 00:13:09,520 --> 00:13:13,880 Speaker 1: with a defect that later had to be corrected in space. 203 00:13:14,040 --> 00:13:17,120 Speaker 1: A team had to be sent up to make some 204 00:13:17,280 --> 00:13:20,640 Speaker 1: tweaks to the Hubble space telescope, so that it would 205 00:13:20,960 --> 00:13:24,000 Speaker 1: perform more closely to what it was supposed to do 206 00:13:25,280 --> 00:13:29,160 Speaker 1: because one of its mirrors was not right at any rate, 207 00:13:29,760 --> 00:13:33,160 Speaker 1: they didn't want to involve a you know, or didn't 208 00:13:33,200 --> 00:13:36,760 Speaker 1: want to invest in a big time project that was unproven, 209 00:13:37,920 --> 00:13:42,520 Speaker 1: especially after the Hubble issue, so they rejected the proposal. 210 00:13:43,240 --> 00:13:45,199 Speaker 1: By the way, in case you're wondering what a lagrange 211 00:13:45,360 --> 00:13:49,439 Speaker 1: orbit is, that refers to five specific orbits around the Sun. 212 00:13:50,480 --> 00:13:52,520 Speaker 1: In two of the orbits L one and L two, 213 00:13:52,880 --> 00:13:56,160 Speaker 1: a spacecraft would orbit the Sun either just inside the 214 00:13:56,200 --> 00:13:59,000 Speaker 1: Earth's orbit or just outside the Earth's orbit. So, in 215 00:13:59,000 --> 00:14:02,199 Speaker 1: other words, if you were look top down, you would 216 00:14:02,280 --> 00:14:06,120 Speaker 1: have a spacecraft that would be just inside of the 217 00:14:06,280 --> 00:14:09,880 Speaker 1: Earth orbit moving at the same speed, or one just 218 00:14:09,960 --> 00:14:12,160 Speaker 1: outside the Earth orbit moving at the same speed as 219 00:14:12,200 --> 00:14:14,920 Speaker 1: the Earth around the Sun. And you might think, well, 220 00:14:14,920 --> 00:14:17,320 Speaker 1: how is that possible? Because earlier you mentioned if you're 221 00:14:17,320 --> 00:14:21,120 Speaker 1: closer in to the star, you move faster, and if 222 00:14:21,160 --> 00:14:23,120 Speaker 1: you're further out from the star, you move slower. So 223 00:14:23,120 --> 00:14:26,280 Speaker 1: how would a spacecraft keep up with the Earth. The 224 00:14:26,320 --> 00:14:30,640 Speaker 1: answer is gravity. Earth's gravitational pull would be enough to 225 00:14:30,800 --> 00:14:35,240 Speaker 1: hold the spacecraft in that orbit, that lagrange orbit, and 226 00:14:35,640 --> 00:14:38,120 Speaker 1: you could do this. You might want to do this 227 00:14:38,160 --> 00:14:40,000 Speaker 1: for lots of reasons. If it's on the inside of 228 00:14:40,000 --> 00:14:43,440 Speaker 1: the Earth's orbit, you could do it to study the 229 00:14:44,640 --> 00:14:48,120 Speaker 1: Sun as it faces Earth. If you did it outside 230 00:14:48,400 --> 00:14:50,920 Speaker 1: the Earth's orbit, you could look away from the Earth 231 00:14:51,040 --> 00:14:53,600 Speaker 1: out into the outer Solar System and not have the 232 00:14:53,600 --> 00:14:57,520 Speaker 1: Earth in the way when you're studying those planets. There's 233 00:14:57,560 --> 00:15:00,520 Speaker 1: also another one. L three Lagrange orbit is on the 234 00:15:00,560 --> 00:15:05,800 Speaker 1: opposite side of the Sun from the Earth, essentially following 235 00:15:06,040 --> 00:15:09,080 Speaker 1: more or less the same orbital path as the Earth. 236 00:15:09,440 --> 00:15:11,720 Speaker 1: This is a great way to see the far side 237 00:15:11,880 --> 00:15:16,360 Speaker 1: of the Sun while the Earth is in its normal location, 238 00:15:17,400 --> 00:15:20,560 Speaker 1: So if you wanted to study the far side of 239 00:15:20,320 --> 00:15:23,960 Speaker 1: the Sun you could do that and look for solar activity. 240 00:15:24,560 --> 00:15:27,120 Speaker 1: Then there's L four and L five, which are sixty 241 00:15:27,160 --> 00:15:31,360 Speaker 1: degrees separated either before or after the Earth's orbit. But 242 00:15:31,560 --> 00:15:34,040 Speaker 1: enough about that. Those are the Lagrange orbits. The idea 243 00:15:34,120 --> 00:15:35,880 Speaker 1: being that when you place something in there, it tends 244 00:15:35,880 --> 00:15:38,800 Speaker 1: to be pretty stable. But NASA had determined that putting 245 00:15:38,800 --> 00:15:41,360 Speaker 1: something into one of those orbits would be really expensive, 246 00:15:43,160 --> 00:15:46,680 Speaker 1: so eventually they came to the conclusion that perhaps they 247 00:15:46,680 --> 00:15:49,840 Speaker 1: would want to just put the Kepler telescope in an 248 00:15:49,960 --> 00:15:52,760 Speaker 1: orbit around the Sun in its own orbit, not a 249 00:15:52,840 --> 00:15:57,480 Speaker 1: lagrange orbit. Meanwhile, engineers started to experiment with charge coupled 250 00:15:57,600 --> 00:16:00,040 Speaker 1: device sensors to see if they could be made to 251 00:16:00,000 --> 00:16:04,600 Speaker 1: detect tiny changes in light, and lab experiments with CCDs 252 00:16:04,720 --> 00:16:06,840 Speaker 1: proved that they were a pretty good candidate for this. 253 00:16:07,560 --> 00:16:10,960 Speaker 1: So let's talk about CCDs for a second. They're designed 254 00:16:10,960 --> 00:16:14,480 Speaker 1: to move an electrical charge, typically in a way that 255 00:16:14,560 --> 00:16:17,680 Speaker 1: allows a device to convert the electrical charge into something else, 256 00:16:17,720 --> 00:16:22,640 Speaker 1: like a digital value. And CCD image sensors are important 257 00:16:22,680 --> 00:16:26,880 Speaker 1: in digital imaging, particularly for highly sensitive imaging, such as 258 00:16:26,920 --> 00:16:29,480 Speaker 1: with very low levels of light. Now you can find 259 00:16:29,520 --> 00:16:33,840 Speaker 1: digital cameras with CCDs, but many also use or rather 260 00:16:34,000 --> 00:16:38,280 Speaker 1: instead they'll use active pixel sensors or the SMOs se 261 00:16:38,400 --> 00:16:43,000 Speaker 1: moss CMOS sensors. And it used to be that there 262 00:16:43,080 --> 00:16:47,920 Speaker 1: was a noticeable gap in quality that CCDs were demonstrably 263 00:16:48,240 --> 00:16:52,200 Speaker 1: much higher quality than sea moss sensors. These days, that 264 00:16:52,280 --> 00:16:57,440 Speaker 1: gap is much more narrow, it's not as blatant as 265 00:16:57,440 --> 00:17:00,800 Speaker 1: it used to be, so we've seen the technology of 266 00:17:00,800 --> 00:17:02,920 Speaker 1: one start to catch up to the technology of the other. 267 00:17:03,720 --> 00:17:07,400 Speaker 1: Within the CCD you have millions of tiny light sensitive 268 00:17:07,480 --> 00:17:12,119 Speaker 1: squares called photo sites, and each photo site corresponds to 269 00:17:12,160 --> 00:17:16,159 Speaker 1: an individual pixel in the final image. It uses the 270 00:17:16,200 --> 00:17:21,560 Speaker 1: photoelectric effect to turn photons into electrons. That's actually an oversimplification. 271 00:17:21,960 --> 00:17:25,640 Speaker 1: It really uses photons to energize electrons push them into 272 00:17:25,760 --> 00:17:29,920 Speaker 1: higher energy bands, and that is the key to how 273 00:17:30,040 --> 00:17:33,920 Speaker 1: CCDs work. Essentially, photons raise the energy level of electrons 274 00:17:33,920 --> 00:17:37,440 Speaker 1: from low energy valence bands to high energy conduction bands. 275 00:17:37,720 --> 00:17:41,320 Speaker 1: And each photo site has a positively charged capacitor when 276 00:17:41,320 --> 00:17:45,320 Speaker 1: the photon converts that electron when it adds that energy 277 00:17:45,359 --> 00:17:48,040 Speaker 1: to an electron, the electron is then attracted to the 278 00:17:48,080 --> 00:17:52,080 Speaker 1: positively charged capacitor and the number of photons that penetrated 279 00:17:52,119 --> 00:17:56,479 Speaker 1: the CCD affects the voltage that this creates, and that 280 00:17:56,560 --> 00:18:00,360 Speaker 1: voltage is then converted into a digital signal. The whole 281 00:18:00,440 --> 00:18:03,959 Speaker 1: array is actually cooled through a series of heat pipes 282 00:18:04,160 --> 00:18:08,119 Speaker 1: that run through an external radiator, so they're actually ratiing 283 00:18:08,200 --> 00:18:12,080 Speaker 1: the heat directly out into space. So as this generates heat, 284 00:18:12,119 --> 00:18:14,600 Speaker 1: they just vent that off into space and it keeps 285 00:18:14,720 --> 00:18:17,560 Speaker 1: the whole thing cool enough for it to operate without 286 00:18:17,600 --> 00:18:22,359 Speaker 1: overheating and causing any problems. Now, in nineteen ninety six, 287 00:18:22,880 --> 00:18:25,560 Speaker 1: two years later. So remember this was first proposed in 288 00:18:25,640 --> 00:18:30,080 Speaker 1: ninety two and rejected, ninety four, rejected, ninety six, proposed again, 289 00:18:30,840 --> 00:18:33,159 Speaker 1: and at this point they started to make some changes. 290 00:18:33,200 --> 00:18:35,760 Speaker 1: One of those was decided to put the telescope into 291 00:18:35,760 --> 00:18:38,840 Speaker 1: a solar orbit rather than a lagrange orbit. It was 292 00:18:38,880 --> 00:18:42,320 Speaker 1: also the point where they renamed the project Kepler, after 293 00:18:42,400 --> 00:18:46,760 Speaker 1: the astronomer we talked about earlier. But this proposal was 294 00:18:46,840 --> 00:18:49,760 Speaker 1: also rejected. This time is because no one at that 295 00:18:49,840 --> 00:18:54,000 Speaker 1: point had proven that a telescope could simultaneously observe thousands 296 00:18:54,080 --> 00:18:56,920 Speaker 1: of stars. One of the big selling points of the 297 00:18:56,960 --> 00:18:59,879 Speaker 1: Kepler telescope is that has a very wide field of 298 00:19:00,200 --> 00:19:04,080 Speaker 1: view and can keep an eye on one hundred thousand 299 00:19:04,160 --> 00:19:11,920 Speaker 1: stars simultaneously. But NASA budget overseers were saying, no one's 300 00:19:11,960 --> 00:19:14,400 Speaker 1: proved that you could do this yet, so researchers went 301 00:19:14,400 --> 00:19:17,120 Speaker 1: to work on a prototype photometer to prove it could 302 00:19:17,200 --> 00:19:21,680 Speaker 1: be done. In nineteen ninety seven, they had finished building 303 00:19:21,800 --> 00:19:25,040 Speaker 1: that prototype photometer, and in nineteen ninety eight they demonstrated 304 00:19:25,240 --> 00:19:27,720 Speaker 1: that it could observe six thousand stars in a single 305 00:19:27,760 --> 00:19:30,000 Speaker 1: field of view and generate data that could then be 306 00:19:30,119 --> 00:19:33,080 Speaker 1: analyzed the results of this project were published in a 307 00:19:33,080 --> 00:19:38,400 Speaker 1: paper in nineteen ninety nine. So nineteen ninety nine, seven 308 00:19:38,480 --> 00:19:44,960 Speaker 1: years after the initial proposal, it's proposed yet again, and 309 00:19:45,000 --> 00:19:49,920 Speaker 1: it got rejected yet again. So why was it rejected 310 00:19:49,960 --> 00:19:53,520 Speaker 1: this time, Well, it was rejected on the grounds that 311 00:19:53,520 --> 00:19:56,560 Speaker 1: there was no evidence the photometer would be precise enough 312 00:19:56,600 --> 00:19:59,840 Speaker 1: to find Earth sized planets that could also operate in 313 00:20:00,119 --> 00:20:04,600 Speaker 1: orbit in the presence of noise. So now the argument was, 314 00:20:04,920 --> 00:20:08,280 Speaker 1: all right, you've shown that it's precise enough to detect 315 00:20:08,680 --> 00:20:11,480 Speaker 1: a planet, but maybe not an Earth sized one because 316 00:20:11,480 --> 00:20:14,159 Speaker 1: those are particularly small. They're not the size of a 317 00:20:14,160 --> 00:20:18,639 Speaker 1: gas giant, so we need to prove that, and we 318 00:20:18,720 --> 00:20:21,000 Speaker 1: aren't sure that if you're in space, you will be 319 00:20:21,040 --> 00:20:25,400 Speaker 1: able to differentiate a planet passing between Earth and its 320 00:20:25,560 --> 00:20:30,800 Speaker 1: host star or just some random piece of space debris 321 00:20:30,880 --> 00:20:35,600 Speaker 1: that happens to pass between a star and Earth. Until 322 00:20:35,600 --> 00:20:38,440 Speaker 1: you can prove that, we're not giving you any monies. 323 00:20:39,280 --> 00:20:42,840 Speaker 1: So the engineers built another test bed and they prove 324 00:20:42,920 --> 00:20:48,600 Speaker 1: that the Kepler telescope could operate satisfactorily even within noise, 325 00:20:48,680 --> 00:20:53,639 Speaker 1: that their analysis would be able to differentiate between false 326 00:20:53,720 --> 00:20:57,399 Speaker 1: positives and the real thing. So two thousand rolls around 327 00:20:57,480 --> 00:21:00,280 Speaker 1: and the Kepler gets proposed one more time, and this 328 00:21:00,400 --> 00:21:03,080 Speaker 1: time it's selected as one of three proposals out of 329 00:21:03,119 --> 00:21:07,080 Speaker 1: a total of twenty six to compete for NASA approval. 330 00:21:08,080 --> 00:21:10,480 Speaker 1: So it then goes on to compete with these other 331 00:21:10,520 --> 00:21:13,679 Speaker 1: two projects. And essentially this is the way NASA works. 332 00:21:13,840 --> 00:21:20,400 Speaker 1: They have teams proposed different potential missions, and then they 333 00:21:20,440 --> 00:21:23,480 Speaker 1: whittle that down to a group of finalists and then 334 00:21:23,560 --> 00:21:28,960 Speaker 1: they say fight it out, convince us to fund your project. 335 00:21:29,800 --> 00:21:34,200 Speaker 1: And sometimes only one project gets funded. And that was 336 00:21:34,240 --> 00:21:37,119 Speaker 1: the case for Kepler, and in two thousand and one 337 00:21:37,160 --> 00:21:41,439 Speaker 1: it won the right to be funded. It became Discovery 338 00:21:41,560 --> 00:21:46,080 Speaker 1: Mission number ten. So the Kepler Telescope is a discovery 339 00:21:46,200 --> 00:21:50,000 Speaker 1: spacecraft by that definition. The actual work on the mission 340 00:21:50,080 --> 00:21:52,840 Speaker 1: began in two thousand and two, and that started with 341 00:21:53,040 --> 00:21:57,600 Speaker 1: orders placed for the detectors for those CCDs, and the 342 00:21:57,600 --> 00:22:01,919 Speaker 1: telescope was completed and lawnlaunched, and it was launched on 343 00:22:01,960 --> 00:22:05,919 Speaker 1: March six, two thousand and nine, and went into space 344 00:22:06,000 --> 00:22:09,480 Speaker 1: around its solar orbit. So here's some stats about the 345 00:22:09,560 --> 00:22:13,560 Speaker 1: Kepler Telescope and the Kepler spacecraft. The diameter of the 346 00:22:13,560 --> 00:22:17,600 Speaker 1: photometer is just shy of a meter. It's point ninety 347 00:22:17,680 --> 00:22:22,000 Speaker 1: five meters in diameter, which is about three feet. The 348 00:22:22,000 --> 00:22:27,359 Speaker 1: camera has a ninety five megapixel array. So your typical 349 00:22:27,400 --> 00:22:31,600 Speaker 1: smartphone has an eight to maybe thirteen megapixel camera on it. 350 00:22:31,640 --> 00:22:35,399 Speaker 1: This one is a ninety five megapixel camera, and it 351 00:22:35,440 --> 00:22:38,199 Speaker 1: can continuously monitor the brightness of more than one hundred 352 00:22:38,200 --> 00:22:43,439 Speaker 1: thousand stars simultaneously. The field of view is thirty three 353 00:22:43,480 --> 00:22:47,600 Speaker 1: thousand times greater than that of the Hubble Space telescope, 354 00:22:47,640 --> 00:22:51,720 Speaker 1: so it's looking at a pretty wide range of space. 355 00:22:52,480 --> 00:22:54,840 Speaker 1: Keep in mind, the Milky Way Galaxy has one hundred 356 00:22:55,160 --> 00:22:58,680 Speaker 1: billion stars in it, so one hundred thousand is nothing. 357 00:22:58,880 --> 00:23:03,360 Speaker 1: It's it's a tiny little drop in an enormous bucket. 358 00:23:04,160 --> 00:23:06,840 Speaker 1: Let's talk about the spacecraft though. The Kepler spacecraft is 359 00:23:06,880 --> 00:23:10,040 Speaker 1: two point seven meters in diameter, that's about nine feet. 360 00:23:10,560 --> 00:23:13,360 Speaker 1: It's four point seven meters tall, that's about fifteen point 361 00:23:13,440 --> 00:23:16,879 Speaker 1: three feet, and it weighed one thousand and fifty two 362 00:23:16,960 --> 00:23:20,240 Speaker 1: point four kilograms or two three hundred and twenty point 363 00:23:20,280 --> 00:23:23,560 Speaker 1: one pounds at the time of launch. Why is it 364 00:23:24,320 --> 00:23:26,840 Speaker 1: just the time of launch, Well, part of that weight 365 00:23:27,119 --> 00:23:30,879 Speaker 1: was taken up by fuel hydrozene propellant, which it has 366 00:23:31,040 --> 00:23:34,840 Speaker 1: used some of since it was launched, there was eleven 367 00:23:34,880 --> 00:23:39,560 Speaker 1: point seven kilograms of fuel at that point, so that 368 00:23:39,640 --> 00:23:41,679 Speaker 1: makes a difference. Also the fact that it's in space 369 00:23:42,320 --> 00:23:44,960 Speaker 1: hard to weigh things. In space. You can talk about mass, 370 00:23:45,240 --> 00:23:50,960 Speaker 1: but weight not as relevant. It generates electricity with one 371 00:23:51,040 --> 00:23:53,840 Speaker 1: hundred and nine point eight square feet or about ten 372 00:23:53,880 --> 00:23:57,879 Speaker 1: point two square meters of solar panels. Now those solar 373 00:23:57,880 --> 00:24:00,960 Speaker 1: panels can provide one thousand and one one hundred watts 374 00:24:01,000 --> 00:24:04,960 Speaker 1: of electrical current. The spacecraft also has a twenty amp 375 00:24:05,040 --> 00:24:08,840 Speaker 1: hour lithium ion battery that's a rechargeable battery, so when 376 00:24:08,880 --> 00:24:13,800 Speaker 1: it's generating excess electricity, it charges the battery and everything 377 00:24:13,880 --> 00:24:18,240 Speaker 1: can continue to be powered. Once it launched, it became 378 00:24:18,320 --> 00:24:21,919 Speaker 1: part of the Exoplanet Exploration Program Office, part of the 379 00:24:22,040 --> 00:24:26,280 Speaker 1: Jet Propulsion Laboratory, so it's been shifted from one group 380 00:24:26,280 --> 00:24:29,399 Speaker 1: in NASA to another one to actually manage the mission. 381 00:24:31,040 --> 00:24:33,520 Speaker 1: So basically, the way the Kepler works, it has more 382 00:24:33,600 --> 00:24:35,720 Speaker 1: than one hundred thousand stars in its view and it 383 00:24:35,760 --> 00:24:38,760 Speaker 1: can detect these very tiny fluctuations in the light from 384 00:24:38,800 --> 00:24:43,520 Speaker 1: those stars, and typically, up until recently, we just had 385 00:24:43,560 --> 00:24:46,400 Speaker 1: to keep those stars under observation for a really long 386 00:24:46,480 --> 00:24:50,639 Speaker 1: time to see if that fluctuation would repeat at regular intervals, 387 00:24:50,920 --> 00:24:54,000 Speaker 1: and it wasn't just something passing between us and the star. 388 00:24:55,000 --> 00:24:58,720 Speaker 1: And that was how we would go from a signal 389 00:24:58,840 --> 00:25:02,240 Speaker 1: that was a potential planet to a verified planet. It 390 00:25:02,280 --> 00:25:05,400 Speaker 1: also explains why, over the course of several years we 391 00:25:05,400 --> 00:25:08,680 Speaker 1: were only able to verify nine hundred eighty four exoplanets, 392 00:25:08,720 --> 00:25:11,959 Speaker 1: with a whole bunch of candidates that maybe are exoplanets 393 00:25:11,960 --> 00:25:14,280 Speaker 1: but were not sure, so he can't call them that. 394 00:25:15,000 --> 00:25:18,119 Speaker 1: But then you had this make tenth announcement of one thousand, 395 00:25:18,160 --> 00:25:21,960 Speaker 1: two hundred eighty four exoplanets. So what changed? How could 396 00:25:22,000 --> 00:25:26,960 Speaker 1: we potentially do that? They actually the researchers had analyzed 397 00:25:27,000 --> 00:25:31,440 Speaker 1: four thousand, three hundred two potential signals these candidate planets, 398 00:25:32,160 --> 00:25:34,440 Speaker 1: and out of those four thousand, three hundred two they 399 00:25:34,840 --> 00:25:38,560 Speaker 1: decided that one two hundred eighty four should be verified 400 00:25:38,680 --> 00:25:41,639 Speaker 1: as actual exoplanets because they had a greater than ninety 401 00:25:41,760 --> 00:25:44,879 Speaker 1: nine percent certainty that they were in fact planets and 402 00:25:44,920 --> 00:25:49,640 Speaker 1: not some anomaly or impostor, as they called them. This 403 00:25:50,080 --> 00:25:53,720 Speaker 1: is pretty phenomenal, right, This is the fact that they 404 00:25:53,760 --> 00:25:58,080 Speaker 1: could more than double them. They also had said there 405 00:25:58,119 --> 00:26:01,800 Speaker 1: were another one than three hundred twenty seven signals that 406 00:26:01,880 --> 00:26:04,520 Speaker 1: have a better than fifty percent chance of actually being 407 00:26:04,520 --> 00:26:09,000 Speaker 1: a planet, but those would require more research and observation 408 00:26:09,240 --> 00:26:12,399 Speaker 1: before NASA would go so far as to say, yeah, 409 00:26:12,440 --> 00:26:14,840 Speaker 1: here are some These will also join the list of 410 00:26:14,960 --> 00:26:20,160 Speaker 1: verified planets. They had a very high threshold to call 411 00:26:20,520 --> 00:26:23,080 Speaker 1: a signal a planet. It had to be greater than 412 00:26:23,160 --> 00:26:28,160 Speaker 1: ninety nine percent certainty. So that's pretty incredible, much higher 413 00:26:28,160 --> 00:26:31,119 Speaker 1: standards than I have. I'd be cool with sixty percent 414 00:26:32,160 --> 00:26:36,480 Speaker 1: now as a throwbag. The first Earth sized planet that 415 00:26:36,680 --> 00:26:40,240 Speaker 1: Kepler telescope found in a potential habitable zone, also known 416 00:26:40,280 --> 00:26:44,520 Speaker 1: as the Goldilucks zone was Kepler one to eight six 417 00:26:44,920 --> 00:26:49,560 Speaker 1: F and the Goliluck zone that's what we think, that's 418 00:26:49,600 --> 00:26:52,479 Speaker 1: the band of orbits we think would be would be 419 00:26:52,520 --> 00:26:55,960 Speaker 1: amenable for life to exist, for water to exist in 420 00:26:56,040 --> 00:26:59,720 Speaker 1: liquid form. The Goldilock zone is dependent upon lots of 421 00:26:59,720 --> 00:27:04,159 Speaker 1: staf like the not just how close you are to 422 00:27:04,240 --> 00:27:07,240 Speaker 1: the host star, but how old is that host star. 423 00:27:08,000 --> 00:27:10,840 Speaker 1: You know, if it's an older star that's burned out 424 00:27:10,840 --> 00:27:12,760 Speaker 1: a lot of its energy, it's a cooler star. So 425 00:27:12,800 --> 00:27:14,960 Speaker 1: you have to be closer to the to the star 426 00:27:15,640 --> 00:27:18,840 Speaker 1: in order to get enough energy to support life. As 427 00:27:18,880 --> 00:27:23,120 Speaker 1: we know it, so it's depend upon a lot of factors. 428 00:27:23,200 --> 00:27:26,280 Speaker 1: In the case of Kepler one eight six F, the 429 00:27:26,440 --> 00:27:31,720 Speaker 1: host star is older than our sun, it is more red, 430 00:27:32,359 --> 00:27:36,080 Speaker 1: and it's cooler. And this also means that if there 431 00:27:36,200 --> 00:27:39,199 Speaker 1: is in fact life on Kepler one eight six F, 432 00:27:40,200 --> 00:27:43,480 Speaker 1: it probably looks different from life on our planet. It's 433 00:27:43,640 --> 00:27:47,960 Speaker 1: receiving a lot of red wavelength photons coming in, which 434 00:27:48,000 --> 00:27:50,719 Speaker 1: could mean that the plants themselves might look very different. 435 00:27:50,800 --> 00:27:55,080 Speaker 1: They might be big red plants all over one eight 436 00:27:55,119 --> 00:27:57,919 Speaker 1: six F, or it could be a barren wasteland. We 437 00:27:57,960 --> 00:28:00,840 Speaker 1: don't know. We have no way of telling yet. We 438 00:28:00,840 --> 00:28:03,840 Speaker 1: can just make some guesses based upon the age of 439 00:28:03,840 --> 00:28:07,199 Speaker 1: the star, the size of the star, the distance that 440 00:28:07,240 --> 00:28:10,440 Speaker 1: we estimate the planet is from that star, those sort 441 00:28:10,480 --> 00:28:11,879 Speaker 1: of things. Those are the kind of things that we 442 00:28:11,920 --> 00:28:16,840 Speaker 1: can kind of start to draw some basic guesses around, 443 00:28:16,960 --> 00:28:19,760 Speaker 1: But they're still gases until we can develop some other 444 00:28:19,880 --> 00:28:24,639 Speaker 1: means of really looking at these distant planets. Got a 445 00:28:24,640 --> 00:28:26,720 Speaker 1: little bit more to say about the Kepler telescope and 446 00:28:26,800 --> 00:28:29,000 Speaker 1: how that sucker works, but before we do that, let's 447 00:28:29,040 --> 00:28:41,040 Speaker 1: take another quick break. Now, out of all the one 448 00:28:41,560 --> 00:28:46,640 Speaker 1: two hundred and eighty four planets announced by this research team. 449 00:28:47,560 --> 00:28:52,160 Speaker 1: Nine of those are considered potentially habitable, meaning that they 450 00:28:52,200 --> 00:28:56,160 Speaker 1: are relatively the same size as Earth or no greater 451 00:28:56,240 --> 00:28:59,480 Speaker 1: than two times the size of Earth, and within their 452 00:29:00,080 --> 00:29:06,760 Speaker 1: host stars Goldilocks zone. Now what's really cool is to 453 00:29:06,880 --> 00:29:09,600 Speaker 1: look at how they determined this, Like what was the 454 00:29:09,600 --> 00:29:14,560 Speaker 1: way that they verified these planets? And they used a 455 00:29:14,600 --> 00:29:19,360 Speaker 1: probabilistic approach, meaning what is the probability that any given 456 00:29:19,400 --> 00:29:22,800 Speaker 1: signal is in fact a planet. Essentially, they were looking 457 00:29:22,800 --> 00:29:26,920 Speaker 1: at two main factors. How much does a single transit 458 00:29:26,960 --> 00:29:30,560 Speaker 1: signal resemble what we would expect from a transiting planet, 459 00:29:31,160 --> 00:29:34,360 Speaker 1: so does it look like what a planet would look 460 00:29:34,400 --> 00:29:37,680 Speaker 1: like when passing in front of a star. And then also, 461 00:29:37,720 --> 00:29:41,640 Speaker 1: what is the likelihood that that particular signal could have 462 00:29:41,680 --> 00:29:45,240 Speaker 1: been caused by an impostor? And you take these two 463 00:29:45,840 --> 00:29:49,760 Speaker 1: ideas into account and you try to figure out what 464 00:29:49,920 --> 00:29:52,800 Speaker 1: is the likelihood that we have and a real legitimate 465 00:29:52,880 --> 00:29:58,280 Speaker 1: hit here. One of the people associated with this mission, 466 00:29:58,600 --> 00:30:02,320 Speaker 1: Timothy Morton, who's in a research scholar at Princeton University, 467 00:30:02,680 --> 00:30:06,440 Speaker 1: calculate the probability that any given transit signal is actually 468 00:30:06,480 --> 00:30:11,280 Speaker 1: a planet by using this and essentially you've got numbers 469 00:30:11,280 --> 00:30:14,400 Speaker 1: between zero and one, and only the results that were 470 00:30:14,440 --> 00:30:17,360 Speaker 1: as close to one as possible ninety nine percent better 471 00:30:17,360 --> 00:30:20,160 Speaker 1: than ninety nine percent in fact, were kept and verified 472 00:30:20,200 --> 00:30:23,680 Speaker 1: as a planet. Now, the big advantage of this approach 473 00:30:23,720 --> 00:30:27,080 Speaker 1: is that it can be applied to many signals simultaneously. 474 00:30:27,800 --> 00:30:32,720 Speaker 1: Instead of having to continuously review the data of a 475 00:30:32,760 --> 00:30:37,240 Speaker 1: single signal and look for those replicable results, you could 476 00:30:37,400 --> 00:30:42,200 Speaker 1: take this approach and apply it across multiple planets all 477 00:30:42,280 --> 00:30:44,800 Speaker 1: at the same time and see which ones come out 478 00:30:44,840 --> 00:30:48,200 Speaker 1: at greater than ninety nine percent certainty. Or, as Morton said, 479 00:30:48,360 --> 00:30:50,400 Speaker 1: if you drop a few large crumbs on the floor, 480 00:30:50,760 --> 00:30:52,600 Speaker 1: you can pick those up one by one, but if 481 00:30:52,640 --> 00:30:55,680 Speaker 1: you spill a whole bag of tiny crumbs, you're going 482 00:30:55,720 --> 00:30:59,040 Speaker 1: to need a broom. And the statistical analysis approach is 483 00:30:59,120 --> 00:31:05,920 Speaker 1: their broom. So we've got out of all the different 484 00:31:06,560 --> 00:31:10,200 Speaker 1: planets found about five hundred and fifty of the two 485 00:31:10,240 --> 00:31:13,720 Speaker 1: hundred and eighty four that were announced on May tenth, 486 00:31:14,680 --> 00:31:16,680 Speaker 1: about five hundred and fifty of them might be rocky 487 00:31:16,720 --> 00:31:19,240 Speaker 1: planets like Earth, and out of those, only nine are 488 00:31:19,280 --> 00:31:23,080 Speaker 1: considered to occupy the habitable zone. And you might think, well, 489 00:31:23,080 --> 00:31:26,280 Speaker 1: that's a really small number nine. How many were there before? 490 00:31:26,720 --> 00:31:29,880 Speaker 1: The answer was twelve, so there were a dozen discovered 491 00:31:29,960 --> 00:31:33,240 Speaker 1: before this announcement. Nine more added to it, for a 492 00:31:33,280 --> 00:31:36,600 Speaker 1: total of twenty one. There are several others that are 493 00:31:36,760 --> 00:31:41,160 Speaker 1: possible candidates for rocky like planets that could be in 494 00:31:41,200 --> 00:31:43,960 Speaker 1: the Goldilock zone, but they don't meet that criteria of 495 00:31:44,040 --> 00:31:48,000 Speaker 1: ninety nine percent yet, so they have not been verified. 496 00:31:48,520 --> 00:31:51,880 Speaker 1: There's just been twenty one verified planets that are of 497 00:31:52,840 --> 00:32:00,920 Speaker 1: rocky most likely anyway rocky consistency and in that Goldiluck zone. 498 00:32:01,080 --> 00:32:04,840 Speaker 1: So this is also we got to remember based on 499 00:32:04,880 --> 00:32:08,040 Speaker 1: that assumption that liquid water is a necessary prerequisite. If 500 00:32:08,040 --> 00:32:11,360 Speaker 1: it's not, then obviously we could be looking at lots 501 00:32:11,400 --> 00:32:14,440 Speaker 1: of different plants that could potentially support life, might not 502 00:32:14,440 --> 00:32:18,600 Speaker 1: be life that we would recognize. However, so the kepler, 503 00:32:18,680 --> 00:32:22,800 Speaker 1: as awesome as it is, cannot detect all the exoplanets 504 00:32:23,080 --> 00:32:27,080 Speaker 1: orbiting stars. If the planet's orbit isn't at the right 505 00:32:27,160 --> 00:32:31,600 Speaker 1: angle from our perspective, From the kepler's perspective, it won't 506 00:32:31,600 --> 00:32:35,320 Speaker 1: detect any dimming. In other words, if there's a planet 507 00:32:35,360 --> 00:32:37,840 Speaker 1: crossing that star, but it's at an angle that does 508 00:32:37,960 --> 00:32:41,320 Speaker 1: not go in front of the star from our perspective, 509 00:32:42,200 --> 00:32:45,320 Speaker 1: the star doesn't dim, we don't see any change in that, 510 00:32:46,000 --> 00:32:48,920 Speaker 1: and the kepler can't detect it. So how many plants 511 00:32:48,960 --> 00:32:51,840 Speaker 1: are actually passing at the correct angle for Kepler to 512 00:32:51,920 --> 00:32:54,840 Speaker 1: detect them well. The probability of such a thing is 513 00:32:54,840 --> 00:32:57,760 Speaker 1: determined by the diameter of the star divided by the 514 00:32:57,760 --> 00:33:00,680 Speaker 1: diameter of the orbit, which, for a planet the size 515 00:33:00,720 --> 00:33:04,480 Speaker 1: of Earth orbiting a star similar to the Sun eventually 516 00:33:04,480 --> 00:33:07,520 Speaker 1: gives you a point five percent chance of detecting that signal. 517 00:33:08,440 --> 00:33:11,520 Speaker 1: Of being at the right angle to detect that signal 518 00:33:11,560 --> 00:33:17,000 Speaker 1: point five percent half a percent chance of detecting the 519 00:33:17,000 --> 00:33:19,560 Speaker 1: signal in the first place. Bigger plants have a better 520 00:33:19,600 --> 00:33:23,080 Speaker 1: probability because they are more likely to at least pass 521 00:33:23,120 --> 00:33:26,840 Speaker 1: over a star partially dependent on you know, they have 522 00:33:27,320 --> 00:33:30,600 Speaker 1: fewer angles where you won't see anything at all, So 523 00:33:30,880 --> 00:33:33,640 Speaker 1: a much bigger planet like something like Jupiter could be 524 00:33:33,680 --> 00:33:37,360 Speaker 1: closer to a ten percent chance. So it's entirely possible, 525 00:33:37,360 --> 00:33:40,920 Speaker 1: and even probable in fact, that what we have detected 526 00:33:41,040 --> 00:33:43,400 Speaker 1: is just a tiny fraction of what is actually out there. 527 00:33:43,480 --> 00:33:46,000 Speaker 1: Even just with the one hundred thousand or so stars 528 00:33:46,000 --> 00:33:48,960 Speaker 1: we've looked at, more like one hundred and fifty thousand. 529 00:33:49,680 --> 00:33:51,720 Speaker 1: But even though we've looked at one hundred and fifty 530 00:33:51,720 --> 00:33:54,480 Speaker 1: thousand stars and we've detected so many of these exoplants 531 00:33:54,480 --> 00:33:56,840 Speaker 1: so far, there could be a lot more that we 532 00:33:57,000 --> 00:34:01,320 Speaker 1: just can't see because of the angle. And then you 533 00:34:01,360 --> 00:34:04,760 Speaker 1: take into account we're looking at one hundred thousand out 534 00:34:04,760 --> 00:34:08,360 Speaker 1: of one hundred billion, and the mind really starts to boggle. 535 00:34:08,440 --> 00:34:13,320 Speaker 1: We realize that the frequency of planets around other stars 536 00:34:13,520 --> 00:34:17,880 Speaker 1: is much greater than we anticipated, and that we even 537 00:34:18,000 --> 00:34:21,920 Speaker 1: may be looking at more planets in the Milky Way 538 00:34:21,960 --> 00:34:24,160 Speaker 1: than there are stars. So if you have one hundred 539 00:34:24,200 --> 00:34:26,960 Speaker 1: billion stars and there's more than one hundred billion planets, 540 00:34:28,160 --> 00:34:32,600 Speaker 1: you think, Wow, the odds of the chances that there 541 00:34:32,680 --> 00:34:36,480 Speaker 1: is another planet within our galaxy that could potentially support 542 00:34:36,600 --> 00:34:39,920 Speaker 1: life are pretty good. It may not be anywhere close 543 00:34:39,960 --> 00:34:42,080 Speaker 1: to us. It may be on the other side of 544 00:34:42,080 --> 00:34:44,759 Speaker 1: the Milky Way galaxy from where we are, but the 545 00:34:44,840 --> 00:34:48,200 Speaker 1: chances are pretty good that there's at least some other 546 00:34:48,239 --> 00:34:52,399 Speaker 1: planets within our own galaxy, let alone the universe, which 547 00:34:52,440 --> 00:34:56,160 Speaker 1: is filled with billions of galaxies. And suddenly you think 548 00:34:56,320 --> 00:35:00,120 Speaker 1: there's no way that we're the only life forms in 549 00:35:00,160 --> 00:35:07,960 Speaker 1: the universe. That's just not statistically plausible. Is it possible? Well, 550 00:35:08,600 --> 00:35:14,359 Speaker 1: I mean, technically I guess so, but it's certainly not plausible. 551 00:35:15,040 --> 00:35:19,320 Speaker 1: It's more likely that there's life on lots of other planets. 552 00:35:19,360 --> 00:35:23,319 Speaker 1: Whether it's evolved life that is intelligent, that's another matter. 553 00:35:24,320 --> 00:35:28,239 Speaker 1: Whether it's life that is anywhere remotely close to us 554 00:35:28,239 --> 00:35:31,160 Speaker 1: where we would ever have an opportunity to discover it 555 00:35:32,440 --> 00:35:39,960 Speaker 1: through communication, that's highly debatable. It's quite possible that any 556 00:35:40,040 --> 00:35:42,600 Speaker 1: life that's that advanced is so far away from us 557 00:35:42,640 --> 00:35:46,560 Speaker 1: that we haven't had enough time to pass for any 558 00:35:46,600 --> 00:35:50,879 Speaker 1: communication generated by that civilization to get to us. Because 559 00:35:50,920 --> 00:35:53,000 Speaker 1: remember that stuff has to travel at the speed of light. 560 00:35:53,040 --> 00:35:56,920 Speaker 1: That's as fast as you can go barring some huge 561 00:35:57,080 --> 00:36:02,759 Speaker 1: change in physics, and so if you are thousands of 562 00:36:02,840 --> 00:36:05,360 Speaker 1: light years away, it's going to take thousands of years 563 00:36:05,360 --> 00:36:07,399 Speaker 1: from the generation of a signal for it to get 564 00:36:07,440 --> 00:36:11,680 Speaker 1: to its destination. And by then the milk has gone bad, 565 00:36:11,960 --> 00:36:15,600 Speaker 1: and that shopping list that the aliens gave us is 566 00:36:15,640 --> 00:36:17,920 Speaker 1: not really going to do anyone any good. The party 567 00:36:18,080 --> 00:36:21,880 Speaker 1: is over. But still it's really exciting to think about 568 00:36:21,920 --> 00:36:24,959 Speaker 1: what the Kepler telescope has done. Now, keep in mind, 569 00:36:24,960 --> 00:36:27,279 Speaker 1: this is very different from other types of telescopes. There 570 00:36:27,280 --> 00:36:31,239 Speaker 1: are other ways of detecting the potential for exoplanets. One 571 00:36:31,239 --> 00:36:33,640 Speaker 1: of those is to look at stars and look to 572 00:36:33,680 --> 00:36:37,160 Speaker 1: see if they are moving at all, like if there's 573 00:36:37,160 --> 00:36:40,040 Speaker 1: a little jiggle, which could indicate that there is a 574 00:36:40,080 --> 00:36:43,520 Speaker 1: gravitational pull upon that star, and that in turn can 575 00:36:43,560 --> 00:36:45,880 Speaker 1: indicate that there is a planet in orbit around the 576 00:36:45,920 --> 00:36:49,200 Speaker 1: start and the planet's gravitational pull in the star is 577 00:36:49,239 --> 00:36:52,560 Speaker 1: causing it to move just a little bit, and that 578 00:36:52,640 --> 00:36:55,480 Speaker 1: we can detect that. That's another way of detecting at 579 00:36:55,560 --> 00:36:59,520 Speaker 1: least the potential of an exoplanet in that star's orbit, 580 00:37:00,680 --> 00:37:04,239 Speaker 1: but it's different obviously from the transit method. And then 581 00:37:04,280 --> 00:37:06,719 Speaker 1: there are ways where we can look at planets to 582 00:37:06,760 --> 00:37:10,120 Speaker 1: try and determine what are they made of, and we 583 00:37:10,200 --> 00:37:13,839 Speaker 1: usually use spectroscopy for that, where we take the light 584 00:37:14,520 --> 00:37:18,319 Speaker 1: reflected off of a planet and we analyze that light 585 00:37:18,400 --> 00:37:21,040 Speaker 1: and we break it down into the various wavelengths, and 586 00:37:21,080 --> 00:37:24,239 Speaker 1: then we start to make very educated guesses about the 587 00:37:24,280 --> 00:37:29,040 Speaker 1: types of elements that are present on that particular planet. 588 00:37:29,480 --> 00:37:35,040 Speaker 1: Even so, this is still largely working from very educated guesses, 589 00:37:36,080 --> 00:37:40,839 Speaker 1: so educated that you could argue they are as good 590 00:37:40,880 --> 00:37:43,840 Speaker 1: as fact at least in some cases, but you have 591 00:37:43,880 --> 00:37:47,040 Speaker 1: to keep in mind there's still a tiny room for error. 592 00:37:47,800 --> 00:37:50,279 Speaker 1: So that about wraps it up for the Kepler Telescope. 593 00:37:50,360 --> 00:37:53,279 Speaker 1: It has served us well. Its primary mission is over. 594 00:37:54,719 --> 00:37:57,200 Speaker 1: We will continue to look at the data from the 595 00:37:57,280 --> 00:38:01,720 Speaker 1: Kepler telescope for many more years, but the actual data 596 00:38:01,800 --> 00:38:06,359 Speaker 1: gathering portion of the Kepler's life is over. There are 597 00:38:06,360 --> 00:38:09,200 Speaker 1: other telescopes that we're playing on launching that will continue 598 00:38:09,239 --> 00:38:12,920 Speaker 1: this work. It'll either be looking for similar planets to 599 00:38:13,440 --> 00:38:16,880 Speaker 1: what Kepler was looking for or different style planets. But 600 00:38:17,120 --> 00:38:20,040 Speaker 1: we're just getting started, and the hope is that we 601 00:38:20,120 --> 00:38:23,839 Speaker 1: will eventually be able to draw some very firm conclusions 602 00:38:23,920 --> 00:38:26,960 Speaker 1: about the presence of life within our galaxy, and this 603 00:38:27,040 --> 00:38:29,839 Speaker 1: could just be the first step toward that. So while 604 00:38:29,880 --> 00:38:33,200 Speaker 1: a lot of those news outlets were perhaps being a 605 00:38:33,200 --> 00:38:38,320 Speaker 1: bit optimistic about the announcement of the discovery of alien life, 606 00:38:39,360 --> 00:38:42,400 Speaker 1: it is true that this is a step toward making 607 00:38:42,480 --> 00:38:46,160 Speaker 1: such a discovery, and it may be many, many, many 608 00:38:46,200 --> 00:38:50,319 Speaker 1: more decades before we're able to say, yes, we've detected 609 00:38:50,360 --> 00:38:54,879 Speaker 1: the presence of life on another planet. But it's through 610 00:38:54,960 --> 00:38:58,840 Speaker 1: work like the Kepler mission that we'll get there. So 611 00:38:58,960 --> 00:39:03,400 Speaker 1: this is a really cool science and technology story, and 612 00:39:03,440 --> 00:39:05,279 Speaker 1: I just wanted to touch on that because I love 613 00:39:05,440 --> 00:39:07,799 Speaker 1: that announcement. I actually listened to it live while they 614 00:39:07,800 --> 00:39:10,360 Speaker 1: were talking about and it was just really cool to 615 00:39:10,440 --> 00:39:14,799 Speaker 1: hear a group of engineers and scientists talk about their 616 00:39:14,840 --> 00:39:18,799 Speaker 1: life's work with such passion. I hope you enjoyed that 617 00:39:18,960 --> 00:39:21,440 Speaker 1: classic episode of tech Stuff that published on June eighth, 618 00:39:21,520 --> 00:39:25,600 Speaker 1: twenty sixteen, about how the Kepler telescope works. I love 619 00:39:25,640 --> 00:39:30,000 Speaker 1: doing these episodes about telescopes because it's fascinating to me 620 00:39:30,120 --> 00:39:33,839 Speaker 1: just how they work, how they function, and then on 621 00:39:33,880 --> 00:39:37,279 Speaker 1: top of that, to learn about the incredible science that 622 00:39:37,560 --> 00:39:41,399 Speaker 1: we were able to achieve thanks to these instruments. It's 623 00:39:41,440 --> 00:39:44,440 Speaker 1: really inspiring stuff. If you have suggestions for topics I 624 00:39:44,440 --> 00:39:47,120 Speaker 1: should cover in future episodes of tech Stuff, there are 625 00:39:47,120 --> 00:39:49,319 Speaker 1: a couple of different ways that you can let me know. 626 00:39:49,480 --> 00:39:52,439 Speaker 1: One is you can download the iHeartRadio app. It's free 627 00:39:52,440 --> 00:39:55,399 Speaker 1: to downloads free to use. 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For more podcasts from iHeartRadio, 637 00:40:34,640 --> 00:40:38,360 Speaker 1: visit the iHeartRadio app, Apple Podcasts, or wherever you listen 638 00:40:38,400 --> 00:40:43,319 Speaker 1: to your favorite shows.