1 00:00:04,240 --> 00:00:12,320 Speaker 1: Get technology with tech Stuff from dot Com. Hey there, 2 00:00:12,400 --> 00:00:15,800 Speaker 1: and welcome to tech Stuff. I'm your host, Jonathan Strickland, 3 00:00:16,200 --> 00:00:20,000 Speaker 1: and today I want to talk about an awesome spacecraft, 4 00:00:20,079 --> 00:00:24,000 Speaker 1: the Kepler Telescope. I've talked about this on the Forward 5 00:00:24,000 --> 00:00:26,720 Speaker 1: Thinking podcast, so if you've listened to Forward Thinking, you're 6 00:00:26,720 --> 00:00:29,640 Speaker 1: gonna hear some stuff that you've probably heard before. Although 7 00:00:29,680 --> 00:00:33,520 Speaker 1: this is really going to focus pun completely intended, let's 8 00:00:33,560 --> 00:00:37,320 Speaker 1: be honest on just the Kepler Telescope. And the reason 9 00:00:37,360 --> 00:00:39,559 Speaker 1: why I'm doing this in the first place is because 10 00:00:39,680 --> 00:00:43,960 Speaker 1: in May, researchers with the Kepler Mission at NASA held 11 00:00:43,960 --> 00:00:46,560 Speaker 1: a press conference in which they announced the largest number 12 00:00:46,640 --> 00:00:51,720 Speaker 1: of exo planets verified ever at a single event, and 13 00:00:51,800 --> 00:00:57,280 Speaker 1: that was one thousand, two eight four verified exo planets. Previously, 14 00:00:57,720 --> 00:01:00,480 Speaker 1: from two thousand nine, up to that point, the mission 15 00:01:00,520 --> 00:01:05,440 Speaker 1: had identified and verified four planets, so this announcement was 16 00:01:05,480 --> 00:01:10,679 Speaker 1: more than doubling the number of exo planets verified. That's incredible. 17 00:01:11,400 --> 00:01:13,200 Speaker 1: So an exo planet, just in case you don't know, 18 00:01:13,360 --> 00:01:16,040 Speaker 1: is of course a planet that is orbiting another star, 19 00:01:16,240 --> 00:01:19,880 Speaker 1: not the Sun, so it's planets in other star systems, 20 00:01:19,880 --> 00:01:24,640 Speaker 1: solar systems that are light years away from US, and 21 00:01:25,240 --> 00:01:28,000 Speaker 1: it was a really cool thing to hear about all 22 00:01:28,040 --> 00:01:32,279 Speaker 1: these different exo planets that had just been verified. Um, 23 00:01:32,600 --> 00:01:35,560 Speaker 1: what I thought was hilarious was leading up to this 24 00:01:35,600 --> 00:01:42,480 Speaker 1: announcement you had several news outlets that were, uh, guessing 25 00:01:42,720 --> 00:01:44,720 Speaker 1: what was going to happen. It was just it was 26 00:01:44,760 --> 00:01:48,279 Speaker 1: just complete throw stuff against the wall and see what sticks. 27 00:01:48,320 --> 00:01:50,840 Speaker 1: And there were quite a few that had guessed that 28 00:01:51,000 --> 00:01:55,280 Speaker 1: NASA was going to announce that the Kepler mission had 29 00:01:55,320 --> 00:01:59,480 Speaker 1: somehow discovered alien life. Now, once you hear how the 30 00:01:59,560 --> 00:02:02,200 Speaker 1: Kepler telescope works and what it's meant to do, you 31 00:02:02,240 --> 00:02:06,320 Speaker 1: will understand that's really not in the purview of the 32 00:02:06,400 --> 00:02:09,800 Speaker 1: Kepler telescope. It is looking for planets that could potentially 33 00:02:09,840 --> 00:02:14,600 Speaker 1: support life, but it doesn't have the capacity to actually 34 00:02:14,600 --> 00:02:19,280 Speaker 1: detect life on those other planets unless someone sent aliens 35 00:02:19,280 --> 00:02:22,040 Speaker 1: to Earth and they started messing with the Kepler telescope, 36 00:02:22,040 --> 00:02:24,760 Speaker 1: in which case you could say it discovered life, but 37 00:02:24,840 --> 00:02:28,640 Speaker 1: not through its primary mission. That did not happen. As 38 00:02:28,680 --> 00:02:31,480 Speaker 1: far as I know, no aliens have been messing with 39 00:02:31,480 --> 00:02:37,320 Speaker 1: the Kepler telescope. So let's talk about how this telescope 40 00:02:37,320 --> 00:02:41,600 Speaker 1: works and this new verification method that the research team 41 00:02:41,680 --> 00:02:44,760 Speaker 1: used to identify so many exo planets. What was it 42 00:02:45,240 --> 00:02:48,840 Speaker 1: that sped up the process so dramatically as to more 43 00:02:48,880 --> 00:02:53,360 Speaker 1: than double the number of confirmed exoplanets. Plus I'll talk 44 00:02:53,400 --> 00:02:56,400 Speaker 1: a little bit about the new candidates for earthlike plants 45 00:02:56,440 --> 00:03:00,560 Speaker 1: that might be capable of supporting life. So first, let's 46 00:03:00,560 --> 00:03:05,520 Speaker 1: go way back. The Kepler telescope is named after Johann Kepler, 47 00:03:05,960 --> 00:03:09,720 Speaker 1: and astronomer of the late sixteenth and early seventeen centuries. 48 00:03:10,240 --> 00:03:12,399 Speaker 1: That's not the original name of the telescope, by the way, 49 00:03:12,400 --> 00:03:14,840 Speaker 1: but more on that in a little bit. So Johann 50 00:03:14,919 --> 00:03:18,239 Speaker 1: Kepler is most famous for discovering the three major laws 51 00:03:18,280 --> 00:03:21,280 Speaker 1: of planetary motion, although at the time no one called 52 00:03:21,320 --> 00:03:25,680 Speaker 1: them laws. It would take Newton and Newton's observations before 53 00:03:25,720 --> 00:03:30,080 Speaker 1: that really started to become a thing. But law number 54 00:03:30,120 --> 00:03:33,919 Speaker 1: one is that the planets move in elliptical orbits around 55 00:03:33,960 --> 00:03:36,520 Speaker 1: the Sun. Law number two, the time it takes to 56 00:03:36,600 --> 00:03:40,840 Speaker 1: traverse any arc of a planetary orbit is proportional to 57 00:03:40,880 --> 00:03:44,640 Speaker 1: the area of the sector between the central body, for example, 58 00:03:44,800 --> 00:03:47,760 Speaker 1: the Sun and the arc. So you can think of 59 00:03:47,800 --> 00:03:50,160 Speaker 1: the two points along the arc the starting point in 60 00:03:50,200 --> 00:03:53,560 Speaker 1: the endpoint of the arc as your your barriers on 61 00:03:53,560 --> 00:03:57,600 Speaker 1: one side, the Sun being the third point. And what's 62 00:03:57,640 --> 00:04:00,480 Speaker 1: not exactly a triangle because you have a herv line 63 00:04:00,480 --> 00:04:03,600 Speaker 1: on a straight line on the ark side, the area 64 00:04:03,680 --> 00:04:08,280 Speaker 1: within that that is proportional to the time it takes 65 00:04:08,320 --> 00:04:12,280 Speaker 1: to traverse that arc. Essentially, what that tells you is 66 00:04:12,280 --> 00:04:14,720 Speaker 1: that the further out you are from a star, the 67 00:04:14,760 --> 00:04:18,680 Speaker 1: slower your orbit is going to be, and the closer 68 00:04:18,680 --> 00:04:21,159 Speaker 1: and you are to a star, the faster your orbit 69 00:04:21,240 --> 00:04:24,760 Speaker 1: is going to be. Also, there's a relationship between the 70 00:04:24,839 --> 00:04:28,400 Speaker 1: square of a planet's periodic time and the cube of 71 00:04:28,440 --> 00:04:31,080 Speaker 1: the radius of its orbit, which is also known as 72 00:04:31,120 --> 00:04:35,160 Speaker 1: the harmonic law. That's law number three. Now, the Kepler 73 00:04:35,200 --> 00:04:38,400 Speaker 1: mission all started out with a question, which was how 74 00:04:38,520 --> 00:04:42,560 Speaker 1: frequent are other Earth sized planets in our galaxy the 75 00:04:42,600 --> 00:04:47,320 Speaker 1: Milky Way? How common is that? Is the Earth a 76 00:04:47,440 --> 00:04:51,960 Speaker 1: strange outlier that is one in a billion or one 77 00:04:52,000 --> 00:04:55,560 Speaker 1: in ten billion, or or even more rare than that. 78 00:04:55,600 --> 00:04:59,039 Speaker 1: We had no way of knowing. Now that particular space 79 00:04:59,080 --> 00:05:02,200 Speaker 1: based tell us cope, the Kepler telescope tries to answer 80 00:05:02,240 --> 00:05:05,719 Speaker 1: this question by looking for planets using what is called 81 00:05:05,720 --> 00:05:10,719 Speaker 1: the transit method. Now, this method was proposed a few 82 00:05:10,760 --> 00:05:16,040 Speaker 1: times leading up to nineteen one, when Frank Rosenblatt really 83 00:05:16,839 --> 00:05:20,279 Speaker 1: went strong with the idea. He suggested the transit method 84 00:05:20,320 --> 00:05:24,960 Speaker 1: for detecting satellites orbiting other stars. And technically, the way 85 00:05:25,000 --> 00:05:27,600 Speaker 1: this works is that you look at a star and 86 00:05:27,640 --> 00:05:30,720 Speaker 1: you measure the amount of light coming to Earth from 87 00:05:30,760 --> 00:05:34,000 Speaker 1: that star, and you look for any variations and that 88 00:05:34,120 --> 00:05:38,360 Speaker 1: any dimming of that light. Now, if a planet were 89 00:05:38,480 --> 00:05:42,120 Speaker 1: to pass between that star and the Earth, you would 90 00:05:42,160 --> 00:05:46,359 Speaker 1: expect the light from that star to dim a tiny amount, 91 00:05:47,200 --> 00:05:49,599 Speaker 1: and that if you were able to detect that difference, 92 00:05:50,040 --> 00:05:53,280 Speaker 1: and you were able to observe that this happens regularly 93 00:05:54,040 --> 00:05:56,760 Speaker 1: over the course of a given amount of time, you 94 00:05:56,800 --> 00:05:59,320 Speaker 1: could come to the conclusion that what you have seen 95 00:06:00,080 --> 00:06:03,800 Speaker 1: is in fact a planet passing between its host star 96 00:06:04,080 --> 00:06:07,680 Speaker 1: and the Earth. This is what we call transit when 97 00:06:07,720 --> 00:06:11,799 Speaker 1: we see from our perspective a planet crossing its star. 98 00:06:13,080 --> 00:06:18,000 Speaker 1: Now we're looking at the planet making its progress across 99 00:06:18,040 --> 00:06:21,360 Speaker 1: its star in the course of that planet's year. So 100 00:06:21,480 --> 00:06:24,320 Speaker 1: if it's close to the same distance from its host 101 00:06:24,400 --> 00:06:27,680 Speaker 1: star as the Earth is from the Sun, you have 102 00:06:27,720 --> 00:06:30,960 Speaker 1: to wait a long time to verify that that in 103 00:06:31,040 --> 00:06:34,440 Speaker 1: fact is what you saw, especially if you want to 104 00:06:34,560 --> 00:06:39,480 Speaker 1: truly verify it and and get a few periodic uh 105 00:06:39,640 --> 00:06:43,600 Speaker 1: instances of that dimming. And if it has, if it's 106 00:06:43,640 --> 00:06:47,640 Speaker 1: a star that has multiple planets alone that same orbital plane, 107 00:06:48,120 --> 00:06:51,919 Speaker 1: then that's going to cause some confusion too. But by 108 00:06:51,960 --> 00:06:55,160 Speaker 1: by seeing the amount of light that has been dimmed, 109 00:06:56,200 --> 00:07:00,400 Speaker 1: and by detecting how long it takes the this dimming 110 00:07:00,480 --> 00:07:03,560 Speaker 1: to change back to normal, you can start to make 111 00:07:03,680 --> 00:07:08,640 Speaker 1: some conclusions like how big the planet must be, how 112 00:07:08,720 --> 00:07:11,000 Speaker 1: quickly it travels tells you a bit about its orbit. 113 00:07:11,360 --> 00:07:14,320 Speaker 1: It tells you also by that orbit, how close it 114 00:07:14,360 --> 00:07:16,880 Speaker 1: is to its home star. As long as you know 115 00:07:16,920 --> 00:07:19,280 Speaker 1: information about the home star, then you can start to 116 00:07:19,320 --> 00:07:22,560 Speaker 1: make guesses as to how hot the planet is or 117 00:07:22,600 --> 00:07:26,160 Speaker 1: how cold it might be. And this is how you 118 00:07:26,200 --> 00:07:30,600 Speaker 1: start to draw some conclusions about the nature of that planet. 119 00:07:31,120 --> 00:07:36,040 Speaker 1: Ultimately looking for planets that are similar to size, uh 120 00:07:36,920 --> 00:07:40,120 Speaker 1: similar to Earth size, I should say, and similar to 121 00:07:40,240 --> 00:07:42,560 Speaker 1: distance from its host star as the Earth is to 122 00:07:42,600 --> 00:07:45,400 Speaker 1: the Sun. The reason for that is we know that 123 00:07:46,120 --> 00:07:50,360 Speaker 1: if the planet is about two times the size of 124 00:07:50,360 --> 00:07:53,960 Speaker 1: Earth or smaller, it's probably going to have gravity that 125 00:07:54,160 --> 00:07:59,400 Speaker 1: is uh amenable to life as we know it. It's 126 00:07:59,440 --> 00:08:02,360 Speaker 1: gonna probably be a rocky planet as opposed to a 127 00:08:02,400 --> 00:08:06,320 Speaker 1: gas giant. That's also important. It's probably gonna be at 128 00:08:06,360 --> 00:08:09,640 Speaker 1: a temperature that will allow liquid water to be on 129 00:08:09,680 --> 00:08:12,600 Speaker 1: the planet. And since life as we know it depends 130 00:08:12,680 --> 00:08:16,480 Speaker 1: upon the presence of liquid water, that's what we're looking for. 131 00:08:16,640 --> 00:08:18,800 Speaker 1: Keeping in mind that there is the possibility there could 132 00:08:18,800 --> 00:08:22,560 Speaker 1: be life out there in the galaxy that doesn't depend 133 00:08:22,680 --> 00:08:25,560 Speaker 1: upon liquid water. But we have a sample size of 134 00:08:25,680 --> 00:08:29,240 Speaker 1: one planet with life on it, so we have to 135 00:08:29,320 --> 00:08:32,520 Speaker 1: draw our conclusions based upon the limited information we have. 136 00:08:33,160 --> 00:08:37,400 Speaker 1: So assuming that water is in fact necessary for life, 137 00:08:37,520 --> 00:08:41,640 Speaker 1: we need to find other planets that could potentially have 138 00:08:41,840 --> 00:08:46,520 Speaker 1: water on them. So that's kind of guiding the principles 139 00:08:46,600 --> 00:08:52,800 Speaker 1: behind looking for planets through the transit method. But it's 140 00:08:52,960 --> 00:08:56,960 Speaker 1: really really hard to do. Now, let's get back to 141 00:08:57,080 --> 00:08:59,720 Speaker 1: to Frank Rosenblatt for a second. He wasn't just famous 142 00:08:59,760 --> 00:09:04,200 Speaker 1: for suggesting this astronomical approach. He wasn't known as a 143 00:09:04,240 --> 00:09:08,080 Speaker 1: great astronomer. He was actually better known as a leading 144 00:09:08,160 --> 00:09:12,120 Speaker 1: expert in the field of artificial intelligence, particularly in the 145 00:09:12,240 --> 00:09:18,360 Speaker 1: areas of recognizing visual patterns and speech recognition, So that 146 00:09:18,440 --> 00:09:22,320 Speaker 1: was his specific forte. He was really working with computers 147 00:09:22,360 --> 00:09:26,080 Speaker 1: so that they could recognize visual patterns, they could recognize 148 00:09:26,120 --> 00:09:29,080 Speaker 1: when you what you are saying when you talk to them. 149 00:09:29,120 --> 00:09:32,800 Speaker 1: And these are fields that today are really coming into 150 00:09:32,800 --> 00:09:35,599 Speaker 1: their own with stuff like Google's Deep Dream, where it 151 00:09:35,920 --> 00:09:39,320 Speaker 1: starts to recognize patterns even if patterns aren't really in 152 00:09:39,360 --> 00:09:42,920 Speaker 1: the picture. It really enhances that and looks for patterns 153 00:09:43,200 --> 00:09:46,800 Speaker 1: in in the in ways that are really interesting and trippy. 154 00:09:46,920 --> 00:09:50,200 Speaker 1: And speech recognition, which we're all using to some degree 155 00:09:50,280 --> 00:09:54,240 Speaker 1: these days, um often with the personal digital assistance that 156 00:09:54,280 --> 00:09:57,480 Speaker 1: are popping up all over the place. Now here's the problem. 157 00:09:57,640 --> 00:10:02,680 Speaker 1: Rosenblatt's suggested approach as not practical at the time in 158 00:10:02,720 --> 00:10:07,760 Speaker 1: the early seventies. We just lacked the technological sophistication necessary 159 00:10:07,840 --> 00:10:10,960 Speaker 1: to detect and analyze such a very tiny change in 160 00:10:11,000 --> 00:10:14,920 Speaker 1: a star's brightness. If we were looking for an Earth 161 00:10:15,120 --> 00:10:20,160 Speaker 1: sized planet at a distance similar to what Earth is 162 00:10:20,240 --> 00:10:24,640 Speaker 1: from our sun, we're talking about a reduction of one 163 00:10:24,800 --> 00:10:28,560 Speaker 1: ten the brightness of a star, and that dimming lasts 164 00:10:28,640 --> 00:10:32,800 Speaker 1: between two and sixteen hours, so that's not a lot 165 00:10:32,840 --> 00:10:36,680 Speaker 1: of time, and it's certainly not a big difference in brightness. 166 00:10:36,679 --> 00:10:38,800 Speaker 1: You have to have a very sensitive instrument in order 167 00:10:38,800 --> 00:10:40,560 Speaker 1: to be able to pick that up, and that just 168 00:10:40,600 --> 00:10:44,400 Speaker 1: didn't exist in nineteen seventy one. Now, we also have 169 00:10:44,440 --> 00:10:46,160 Speaker 1: to keep in mind that stars tend to be much 170 00:10:46,280 --> 00:10:49,599 Speaker 1: much bigger than planets. For example, the Sun's diameter is 171 00:10:49,640 --> 00:10:52,160 Speaker 1: a hundred and nine times greater than the Earth's diameter, 172 00:10:52,760 --> 00:10:56,400 Speaker 1: and because of that, that's why, with the distances involved 173 00:10:56,440 --> 00:10:59,360 Speaker 1: and the size is involved, it's such a tiny change 174 00:10:59,360 --> 00:11:02,960 Speaker 1: in the brightness of the star. However, NASA began to 175 00:11:03,000 --> 00:11:05,720 Speaker 1: explore how they might be able to use the transit 176 00:11:05,800 --> 00:11:09,960 Speaker 1: method to detect exoplanets in a practical way. Back in 177 00:11:11,480 --> 00:11:14,640 Speaker 1: they were essentially laying out the requirements necessary to detect 178 00:11:14,640 --> 00:11:18,480 Speaker 1: planets with a reasonable amount of confidence. A conference that 179 00:11:18,520 --> 00:11:22,200 Speaker 1: they held on High precision photometry acted as the launching 180 00:11:22,280 --> 00:11:27,680 Speaker 1: ground figuratively speaking for discussions about a space based telescope 181 00:11:27,720 --> 00:11:31,400 Speaker 1: designed to detect a transitting planet. The idea being that 182 00:11:31,880 --> 00:11:36,120 Speaker 1: in space there would be less uh noise in the 183 00:11:36,280 --> 00:11:40,440 Speaker 1: signal to noise ratio you could get it outside the atmosphere. 184 00:11:40,920 --> 00:11:44,400 Speaker 1: The effects of the atmosphere would not be an impediment 185 00:11:44,559 --> 00:11:47,800 Speaker 1: to a space telescope, and it would be more likely 186 00:11:47,840 --> 00:11:52,479 Speaker 1: to pick up something as tiny as this change in brightness. 187 00:11:53,240 --> 00:11:57,360 Speaker 1: So in two NASA proposed new missions to look into 188 00:11:57,400 --> 00:12:00,559 Speaker 1: the possibility of life in our galaxy, and the first 189 00:12:00,600 --> 00:12:03,640 Speaker 1: concept that came up with was called the Frequency of 190 00:12:03,720 --> 00:12:08,200 Speaker 1: Earth Size Inner Planets or FRESIP f R E s 191 00:12:08,240 --> 00:12:13,319 Speaker 1: I P. But that proposal was rejected largely because there 192 00:12:13,400 --> 00:12:16,240 Speaker 1: was doubt at the time that our technological sophistication had 193 00:12:16,240 --> 00:12:19,840 Speaker 1: actually reached a level sufficient to detect any transitting planets 194 00:12:19,840 --> 00:12:22,920 Speaker 1: of Earth like size. So, in other words, if we 195 00:12:23,000 --> 00:12:25,280 Speaker 1: had gone forward with it, we would have built a 196 00:12:25,320 --> 00:12:28,640 Speaker 1: tool that was not up to the task of actually 197 00:12:28,640 --> 00:12:30,480 Speaker 1: doing what was supposed to do, and we would have 198 00:12:30,520 --> 00:12:34,840 Speaker 1: wasted millions of dollars in the process, not something NASA 199 00:12:34,840 --> 00:12:38,720 Speaker 1: could easily afford to do now. Two years later, in 200 00:12:40,400 --> 00:12:44,880 Speaker 1: a team proposed FRESIP again with a space based telescope 201 00:12:44,920 --> 00:12:48,959 Speaker 1: in lagrange orbit, but again a committee determined the price 202 00:12:49,000 --> 00:12:51,200 Speaker 1: would be similar to that of the Hubble, which was 203 00:12:51,440 --> 00:12:55,880 Speaker 1: incredibly expensive and also had been a black eye on 204 00:12:56,040 --> 00:12:59,440 Speaker 1: NASA because when the Hubble launched, it launched with a 205 00:12:59,520 --> 00:13:03,880 Speaker 1: defect that later had to be corrected in space. A 206 00:13:04,160 --> 00:13:07,440 Speaker 1: team had to be sent up to make some tweaks 207 00:13:07,480 --> 00:13:10,520 Speaker 1: to the Hubble. Space telescope so that it would be 208 00:13:10,640 --> 00:13:13,719 Speaker 1: perform more closely to what it was supposed to do 209 00:13:15,000 --> 00:13:18,920 Speaker 1: because one of its mirrors was not right at any rate, 210 00:13:19,480 --> 00:13:22,880 Speaker 1: they didn't want to involve a you know, I didn't 211 00:13:22,920 --> 00:13:25,200 Speaker 1: want to invest in a big time project that was 212 00:13:25,280 --> 00:13:31,560 Speaker 1: unproven um, especially after the Hubble issue, so they rejected 213 00:13:31,600 --> 00:13:34,240 Speaker 1: the proposal. By the way, in case you're wondering what 214 00:13:34,280 --> 00:13:38,280 Speaker 1: a lagrange orbit is, that refers to five specific orbits 215 00:13:38,320 --> 00:13:41,600 Speaker 1: around the Sun. In two of the orbits L one 216 00:13:41,640 --> 00:13:44,640 Speaker 1: and L two, a spacecraft would orbit the Sun either 217 00:13:44,760 --> 00:13:48,599 Speaker 1: just inside the Earth's orbit or just outside the Earth's orbit. So, 218 00:13:48,640 --> 00:13:50,800 Speaker 1: in other words, if you were to look top down, 219 00:13:51,559 --> 00:13:55,200 Speaker 1: you would have a spacecraft that would be just inside 220 00:13:55,320 --> 00:13:59,080 Speaker 1: of the Earth orbit moving at the same speed, or 221 00:13:59,160 --> 00:14:01,440 Speaker 1: one just outside the Earth orbit, moving at the same 222 00:14:01,440 --> 00:14:04,640 Speaker 1: speed as the Earth around the Sun. And you might think, well, 223 00:14:04,640 --> 00:14:07,040 Speaker 1: how is that possible? Because earlier you mentioned if you're 224 00:14:07,080 --> 00:14:10,840 Speaker 1: closer in to the star you move faster, and if 225 00:14:10,880 --> 00:14:12,800 Speaker 1: you're further out from the star, you move slower. So 226 00:14:12,840 --> 00:14:16,360 Speaker 1: how would spacecraft keep up with the Earth. The answer 227 00:14:16,400 --> 00:14:20,800 Speaker 1: is gravity. Earth's gravitational pull would be enough to hold 228 00:14:20,840 --> 00:14:25,440 Speaker 1: the spacecraft in that orbit. That Lagrange orbit, and you 229 00:14:25,480 --> 00:14:28,000 Speaker 1: could do this. You might want to do this for 230 00:14:28,080 --> 00:14:29,840 Speaker 1: lots of reasons. If it's on the inside of the 231 00:14:29,840 --> 00:14:34,600 Speaker 1: Earth's orbit, you could do it to study the Sun 232 00:14:34,920 --> 00:14:38,840 Speaker 1: as it faces Earth. If you did outside the RS orbit, 233 00:14:38,880 --> 00:14:41,520 Speaker 1: you could look away from the Earth out into the 234 00:14:41,560 --> 00:14:43,760 Speaker 1: outer Solar System and not have the Earth in the 235 00:14:43,760 --> 00:14:48,000 Speaker 1: way when you're studying those planets. Um There's also another one. 236 00:14:48,120 --> 00:14:51,560 Speaker 1: L three Lagrange orbit, is on the opposite side of 237 00:14:51,600 --> 00:14:56,400 Speaker 1: the Sun from the Earth, essentially following more or less 238 00:14:56,400 --> 00:14:59,560 Speaker 1: the same orbital path as the Earth. This is a 239 00:14:59,600 --> 00:15:02,200 Speaker 1: great way to see the far side of the Sun 240 00:15:02,520 --> 00:15:07,360 Speaker 1: while the Earth is in its normal location. So if 241 00:15:07,360 --> 00:15:10,720 Speaker 1: you wanted to study the far side of the Sun, 242 00:15:11,160 --> 00:15:14,440 Speaker 1: you could do that and look for solar activity. Then 243 00:15:14,440 --> 00:15:17,240 Speaker 1: there's L four and L five, which are sixty degrees 244 00:15:17,320 --> 00:15:21,440 Speaker 1: separated either before or after the Earth's orbit. But enough 245 00:15:21,480 --> 00:15:24,000 Speaker 1: about that. Those are the Lagrange orbits, the idea being 246 00:15:24,000 --> 00:15:25,680 Speaker 1: that when you play something in there, it tends to 247 00:15:25,680 --> 00:15:28,800 Speaker 1: be pretty stable. But NASA had determined that putting something 248 00:15:28,880 --> 00:15:32,800 Speaker 1: into one of those orbits would be really expensive. Uh 249 00:15:32,880 --> 00:15:36,400 Speaker 1: So eventually they came to the conclusion that perhaps they 250 00:15:36,400 --> 00:15:39,560 Speaker 1: would want to just put the Kepler telescope in an 251 00:15:39,680 --> 00:15:42,440 Speaker 1: orbit around the Sun in its own orbit, not a 252 00:15:42,520 --> 00:15:47,200 Speaker 1: lagrange orbit. Meanwhile, engineers started to experiment with charge coupled 253 00:15:47,320 --> 00:15:49,600 Speaker 1: device sensors to see if they could be made to 254 00:15:49,680 --> 00:15:53,760 Speaker 1: detect tiny changes in light, and lab experiments with c 255 00:15:53,880 --> 00:15:56,280 Speaker 1: c ds proved that they were a pretty good candidate 256 00:15:56,320 --> 00:15:59,480 Speaker 1: for this. So let's talk about c c ds for 257 00:15:59,520 --> 00:16:03,600 Speaker 1: a second. They're designed to move an electrical charge, typically 258 00:16:03,640 --> 00:16:05,720 Speaker 1: in a way that allows a device to convert the 259 00:16:05,720 --> 00:16:09,400 Speaker 1: electrical charge into something else, like a digital value, and 260 00:16:09,600 --> 00:16:13,440 Speaker 1: C c D image sensors are important in digital imaging, 261 00:16:13,440 --> 00:16:17,280 Speaker 1: particularly for highly sensitive imaging, such as with very low 262 00:16:17,400 --> 00:16:20,160 Speaker 1: levels of light. Now you can find digital cameras with 263 00:16:20,240 --> 00:16:24,160 Speaker 1: c c ds, but many also use or rather instead 264 00:16:24,200 --> 00:16:28,680 Speaker 1: they'll use active pixel sensors or the seamost c MOSS 265 00:16:28,760 --> 00:16:32,280 Speaker 1: c m O S sensors. And it used to be 266 00:16:32,440 --> 00:16:35,200 Speaker 1: that there was a noticeable gap in quality, that c 267 00:16:35,320 --> 00:16:39,240 Speaker 1: c D s were demonstrably much higher quality than c 268 00:16:39,440 --> 00:16:43,520 Speaker 1: MOSS sensors. These days, that gap is much more narrow, 269 00:16:44,080 --> 00:16:47,720 Speaker 1: it's not as uh as blatant as it used to be. 270 00:16:48,680 --> 00:16:51,280 Speaker 1: So we've seen the technology of one start to catch 271 00:16:51,360 --> 00:16:53,880 Speaker 1: up to the technology of the other. Within the c 272 00:16:54,040 --> 00:16:57,720 Speaker 1: c D, you have millions of tiny light sensitive squares 273 00:16:57,800 --> 00:17:02,720 Speaker 1: called photo sites, and each photosite corresponds to an individual 274 00:17:02,800 --> 00:17:07,119 Speaker 1: pixel in the final image. It uses the photoelectric effect. 275 00:17:07,200 --> 00:17:11,760 Speaker 1: It turned photons into electrons. That's actually an oversimplification. It 276 00:17:11,800 --> 00:17:15,800 Speaker 1: really uses photons to energize electrons push them into higher 277 00:17:16,359 --> 00:17:21,600 Speaker 1: energy bands, and that is the key to how CCTs work. Essentially, 278 00:17:21,640 --> 00:17:24,399 Speaker 1: photons raise the energy level of electrons from low energy 279 00:17:24,480 --> 00:17:28,040 Speaker 1: valence bands to high energy conduction bands, and each photo 280 00:17:28,080 --> 00:17:32,359 Speaker 1: site has a positively charged capacitor when the photon converts 281 00:17:32,960 --> 00:17:35,800 Speaker 1: that electron when it adds that energy to an electron, 282 00:17:36,119 --> 00:17:39,280 Speaker 1: the electron is then attracted to the positively charged capacitor 283 00:17:39,840 --> 00:17:43,120 Speaker 1: and the number of photons that penetrated the CCD affects 284 00:17:43,160 --> 00:17:46,959 Speaker 1: the voltage that this creates, and that voltage is then 285 00:17:47,000 --> 00:17:50,919 Speaker 1: converted into a digital signal. The whole array is actually 286 00:17:50,920 --> 00:17:54,439 Speaker 1: cooled through a series of heat pipes that run through 287 00:17:54,480 --> 00:17:58,760 Speaker 1: an external radiator, so they're actually rading the heat directly 288 00:17:58,800 --> 00:18:02,159 Speaker 1: out into space. So as this generates heat, they just 289 00:18:02,440 --> 00:18:04,879 Speaker 1: vent that off into space and it keeps the whole 290 00:18:04,920 --> 00:18:08,040 Speaker 1: thing cool enough for it to operate without overheating and 291 00:18:08,080 --> 00:18:13,879 Speaker 1: causing any problems. Now in six two years later. So 292 00:18:13,960 --> 00:18:17,040 Speaker 1: remember this was first proposed in ninety two and rejected, 293 00:18:17,160 --> 00:18:21,520 Speaker 1: ninety four, rejected, nine proposed again, and at this point 294 00:18:21,520 --> 00:18:23,600 Speaker 1: they started to make some changes. One of those was 295 00:18:24,080 --> 00:18:26,600 Speaker 1: decided to put the telescope into a solar orbit rather 296 00:18:26,680 --> 00:18:29,760 Speaker 1: than a lagrange orbit. It was also the point where 297 00:18:29,760 --> 00:18:33,120 Speaker 1: they renamed the project Kepler, after the astronomer we talked 298 00:18:33,119 --> 00:18:38,000 Speaker 1: about earlier. But this proposal was also rejected. This time 299 00:18:38,440 --> 00:18:40,480 Speaker 1: is because no one at that point had proven that 300 00:18:40,520 --> 00:18:45,359 Speaker 1: a telescope could simultaneously observe thousands of stars. One of 301 00:18:45,400 --> 00:18:47,840 Speaker 1: the big selling points of the Kepler telescope is that 302 00:18:47,920 --> 00:18:51,480 Speaker 1: has a very wide field of view and can keep 303 00:18:51,560 --> 00:18:57,240 Speaker 1: an eye on a hundred thousand stars simultaneously. But NASA 304 00:18:58,600 --> 00:19:02,119 Speaker 1: budget oh overseers were saying, no one's proved that you 305 00:19:02,160 --> 00:19:04,520 Speaker 1: could do this yet, so researchers went to work on 306 00:19:04,520 --> 00:19:08,879 Speaker 1: a prototype photometer to prove it could be done. In 307 00:19:08,960 --> 00:19:12,960 Speaker 1: nine seven, they had finished building that prototype photometer and 308 00:19:12,960 --> 00:19:16,879 Speaker 1: in they demonstrated that it could observe six thousand stars 309 00:19:16,880 --> 00:19:19,080 Speaker 1: in a single field of view and generate data that 310 00:19:19,119 --> 00:19:22,240 Speaker 1: could then be analyzed. The results of this project were 311 00:19:22,280 --> 00:19:28,520 Speaker 1: published in a paper in n SO nine, seven years 312 00:19:28,520 --> 00:19:34,760 Speaker 1: after the initial proposal. It's proposed yet again, and it 313 00:19:34,840 --> 00:19:41,359 Speaker 1: got rejected yet again. So why was it rejected this time? Well, 314 00:19:41,840 --> 00:19:43,719 Speaker 1: it was rejected on the grounds that there was no 315 00:19:43,800 --> 00:19:46,960 Speaker 1: evidence the photometer would be precise enough to find Earth 316 00:19:47,080 --> 00:19:50,399 Speaker 1: sized planets that could also operate in orbit in the 317 00:19:50,400 --> 00:19:55,000 Speaker 1: presence of noise. So now the argument was, all right, 318 00:19:55,200 --> 00:19:59,240 Speaker 1: you've shown that it's precise enough to detect a planet, 319 00:19:59,480 --> 00:20:02,439 Speaker 1: but maybe un Earth sized one, because those are particularly small, 320 00:20:02,480 --> 00:20:06,920 Speaker 1: they're not the size of a gas giant. Uh So 321 00:20:07,040 --> 00:20:09,240 Speaker 1: we need to prove that, and we aren't sure that 322 00:20:09,320 --> 00:20:12,000 Speaker 1: if you're in space, you will be able to differentiate 323 00:20:12,080 --> 00:20:17,800 Speaker 1: a planet passing between Earth and its host star or 324 00:20:18,280 --> 00:20:21,280 Speaker 1: just some random piece of space debris that happens to 325 00:20:21,320 --> 00:20:25,840 Speaker 1: pass between a star and Earth, until you can prove 326 00:20:25,960 --> 00:20:30,119 Speaker 1: that we're not giving you any moneys. So the engineers 327 00:20:30,119 --> 00:20:34,159 Speaker 1: built another test bed and they proved that the Kepler 328 00:20:34,200 --> 00:20:40,040 Speaker 1: telescope could operate satisfactorily even within noise, that their analysis 329 00:20:40,359 --> 00:20:44,480 Speaker 1: would be able to differentiate between false positives and the 330 00:20:44,560 --> 00:20:47,960 Speaker 1: real thing. So two thousand rolls around and the Kepler 331 00:20:48,000 --> 00:20:51,119 Speaker 1: gets proposed one more time, and this time it's selected 332 00:20:51,119 --> 00:20:53,439 Speaker 1: as one of three proposals out of a total of 333 00:20:53,480 --> 00:20:58,280 Speaker 1: twenty six to compete ver NASSA approval, So it then 334 00:20:58,359 --> 00:21:01,480 Speaker 1: goes on to compete with the other two projects. And 335 00:21:01,600 --> 00:21:05,560 Speaker 1: essentially this is the way NASA works. They have teams 336 00:21:05,640 --> 00:21:10,679 Speaker 1: proposed different UH potential missions and then they whittle that 337 00:21:10,800 --> 00:21:14,480 Speaker 1: down to a group of finalists and then they say 338 00:21:14,520 --> 00:21:19,760 Speaker 1: fight it out, convince us to fund your project. And 339 00:21:20,480 --> 00:21:24,040 Speaker 1: sometimes only one project gets funded, and that was the 340 00:21:24,080 --> 00:21:27,359 Speaker 1: case for Kepler, and in two thousand one it won 341 00:21:27,480 --> 00:21:32,440 Speaker 1: the right to be funded. It became Discovery Mission number ten. 342 00:21:33,560 --> 00:21:37,639 Speaker 1: So the Kepler Telescope is a discovery spacecraft by that definition. 343 00:21:38,080 --> 00:21:41,240 Speaker 1: The actual work on the mission began in two thousand two, 344 00:21:41,600 --> 00:21:45,119 Speaker 1: and that started with orders placed for the detectors for 345 00:21:45,240 --> 00:21:49,040 Speaker 1: those c c D s and the telescope was completed 346 00:21:49,240 --> 00:21:52,200 Speaker 1: and launched UH and it was launched on March six, 347 00:21:52,240 --> 00:21:56,919 Speaker 1: two thousand nine, and went into space around its solar orbit. 348 00:21:57,240 --> 00:22:00,600 Speaker 1: So here's some stats about the Kepler tell lescope and 349 00:22:00,640 --> 00:22:04,920 Speaker 1: the Kepler spacecraft. The diameter of the photometer is just 350 00:22:05,119 --> 00:22:08,760 Speaker 1: shy of a meter. It's point nine five meters in diameter. 351 00:22:08,840 --> 00:22:12,679 Speaker 1: Which is about three ft. The camera has a ninety 352 00:22:12,800 --> 00:22:18,760 Speaker 1: five megapixel array. So your typical smartphone has an eight 353 00:22:18,800 --> 00:22:21,840 Speaker 1: to maybe thirteen megapixel camera on it. This one is 354 00:22:21,840 --> 00:22:26,359 Speaker 1: a nine five megapixel camera, and it can continuously monitor 355 00:22:26,440 --> 00:22:30,040 Speaker 1: the brightness of more than one hundred thousand stars simultaneously. 356 00:22:31,720 --> 00:22:34,600 Speaker 1: The field of view is thirty three thousand times greater 357 00:22:34,680 --> 00:22:38,199 Speaker 1: than that of the Hubble Space telescope, so it's looking 358 00:22:38,240 --> 00:22:42,760 Speaker 1: at a pretty wide range of space. Keep in mind, 359 00:22:42,760 --> 00:22:46,600 Speaker 1: the Milky Way galaxy has a hundred billion stars in it, 360 00:22:46,680 --> 00:22:50,640 Speaker 1: so a hundred thousand is nothing. It's it's a tiny 361 00:22:50,720 --> 00:22:54,600 Speaker 1: little drop in an enormous bucket. Let's talk about the 362 00:22:54,600 --> 00:22:57,919 Speaker 1: spacecraft though. The Kepler spacecraft is two point seven meters 363 00:22:57,920 --> 00:23:01,240 Speaker 1: in diameter, that's about nine ft. It's four point seven 364 00:23:01,240 --> 00:23:04,800 Speaker 1: meters tall, that's about fifteen point three feet, and it 365 00:23:04,920 --> 00:23:08,800 Speaker 1: weighed one thousand, fifty two point four kilograms or two thousand, 366 00:23:08,800 --> 00:23:11,840 Speaker 1: three hundred twenty point one pounds at the time of launch. 367 00:23:12,800 --> 00:23:15,680 Speaker 1: Why is it just the time of launch, Well, part 368 00:23:15,680 --> 00:23:19,720 Speaker 1: of that weight was taken up by fuel hydrazine propellant, 369 00:23:20,000 --> 00:23:23,360 Speaker 1: which it has used some of since it was launched. 370 00:23:23,920 --> 00:23:27,760 Speaker 1: There was eleven point seven kilograms of fuel at that point, 371 00:23:27,840 --> 00:23:30,920 Speaker 1: so that makes a difference. Also the fact that it's 372 00:23:30,920 --> 00:23:33,760 Speaker 1: in space hard to weigh things in space. You can 373 00:23:33,800 --> 00:23:39,000 Speaker 1: talk about mass, but weight not as relevant. It generates 374 00:23:39,000 --> 00:23:43,040 Speaker 1: electricity with one hundred nine point eight square feet or 375 00:23:43,040 --> 00:23:47,120 Speaker 1: about ten point two square meters of solar panels. Now 376 00:23:47,160 --> 00:23:50,600 Speaker 1: those solar panels can provide one thousand, one hundred watts 377 00:23:50,720 --> 00:23:54,320 Speaker 1: of electrical current. The space cars also has a twenty 378 00:23:54,400 --> 00:23:58,040 Speaker 1: amp hour lithium ion battery that's a rechargeable battery, so 379 00:23:58,359 --> 00:24:01,800 Speaker 1: when it's generating excess electri city, it charges the battery 380 00:24:02,040 --> 00:24:06,640 Speaker 1: and UH and everything can continue to be powered. Once 381 00:24:06,680 --> 00:24:11,199 Speaker 1: it launched, it became part of the Exoplanet Exploration Program Office, 382 00:24:11,240 --> 00:24:15,160 Speaker 1: part of the Jet Propulsion Laboratory, so it's been shifted 383 00:24:15,200 --> 00:24:18,080 Speaker 1: from one group in NASA to another one to actually 384 00:24:18,160 --> 00:24:22,560 Speaker 1: manage the mission. So basically, the way the Kepler works, 385 00:24:22,640 --> 00:24:24,840 Speaker 1: it has more than a hundred thousand stars in its 386 00:24:24,920 --> 00:24:27,879 Speaker 1: view and it can detect these very tiny fluctuations in 387 00:24:27,880 --> 00:24:32,879 Speaker 1: the light from those stars. Typically, up until recently, we 388 00:24:32,960 --> 00:24:35,600 Speaker 1: just had to keep those stars under observation for a 389 00:24:35,600 --> 00:24:39,080 Speaker 1: really long time to see if that fluctuation would repeat 390 00:24:39,160 --> 00:24:42,840 Speaker 1: at regular intervals, and it wasn't just something passing between 391 00:24:42,960 --> 00:24:46,680 Speaker 1: us and the star. And that was how we would 392 00:24:46,720 --> 00:24:50,639 Speaker 1: go from a signal that was a potential planet to 393 00:24:50,760 --> 00:24:53,600 Speaker 1: a verified planet. It also explains why, over the course 394 00:24:53,600 --> 00:24:56,800 Speaker 1: of several years, we were only able to verify n 395 00:24:57,520 --> 00:25:00,640 Speaker 1: exo planets with a whole bunch of candidates that maybe 396 00:25:00,760 --> 00:25:03,480 Speaker 1: or exo planets, but we're not sure, so we can't 397 00:25:03,520 --> 00:25:06,360 Speaker 1: call them that. But then you had this May tenth 398 00:25:06,400 --> 00:25:10,840 Speaker 1: announcement of one thousand two four exo planets. So what changed? 399 00:25:10,920 --> 00:25:15,680 Speaker 1: How could we potentially do that? They actually the researchers 400 00:25:15,760 --> 00:25:20,000 Speaker 1: had analyzed four thousand, three hundred two potential signals, these 401 00:25:20,040 --> 00:25:23,679 Speaker 1: candidate planets, and out of those four thousand, three hundred 402 00:25:23,720 --> 00:25:27,439 Speaker 1: two they decided that one thousand two Night four should 403 00:25:27,440 --> 00:25:30,480 Speaker 1: be verified as actual exo planets because they had a 404 00:25:30,480 --> 00:25:34,560 Speaker 1: greater than certainty that they were in fact planets and 405 00:25:34,640 --> 00:25:39,480 Speaker 1: not some anomaly or impostor as they called them. This 406 00:25:39,840 --> 00:25:43,359 Speaker 1: is pretty phenomenal, right, this is Night the fact that 407 00:25:43,359 --> 00:25:47,360 Speaker 1: they could more than double them. Uh. They also had 408 00:25:47,400 --> 00:25:50,119 Speaker 1: said that there were another one thousand, three hundred seven 409 00:25:50,880 --> 00:25:54,000 Speaker 1: signals that have a better than fifty chance of actually 410 00:25:54,000 --> 00:25:58,000 Speaker 1: being a planet, but those would require more research and 411 00:25:58,119 --> 00:26:02,119 Speaker 1: observation before ASSA would go so far as to say, yeah, 412 00:26:02,160 --> 00:26:04,560 Speaker 1: here are some. These will also join the list of 413 00:26:04,680 --> 00:26:10,320 Speaker 1: verified planets and are very high threshold. To call a 414 00:26:10,400 --> 00:26:15,280 Speaker 1: signal a planet, it had to be greater than certainty. 415 00:26:15,320 --> 00:26:18,679 Speaker 1: So that's pretty incredible, much higher standards than I have. 416 00:26:19,359 --> 00:26:24,480 Speaker 1: I'd be cool with now. As a throwback, the first 417 00:26:24,560 --> 00:26:28,400 Speaker 1: Earth size planet that Kepler telescope found in a potential 418 00:26:28,520 --> 00:26:33,240 Speaker 1: habitable zone, also known as the Goldilocks zone, was Kepler 419 00:26:33,359 --> 00:26:37,560 Speaker 1: one eight six f UH, and the Goldilocks zone that's 420 00:26:37,600 --> 00:26:40,760 Speaker 1: what we think. That's the band of orbits we think 421 00:26:40,800 --> 00:26:44,280 Speaker 1: would be UH would be amenable for life to exist, 422 00:26:44,320 --> 00:26:48,280 Speaker 1: for water to exist in liquid form. The Goldilocks zone 423 00:26:48,320 --> 00:26:52,600 Speaker 1: is dependent upon lots of stuff like the not just 424 00:26:52,680 --> 00:26:55,200 Speaker 1: how close you are to the host star, but how 425 00:26:55,280 --> 00:26:58,400 Speaker 1: old is that host star. You know, if it's an 426 00:26:58,400 --> 00:27:01,399 Speaker 1: older star that's burned out a lot of its energy, 427 00:27:01,400 --> 00:27:03,560 Speaker 1: it's a cooler star. So you have to be closer 428 00:27:03,600 --> 00:27:06,320 Speaker 1: to the to the star in order to get enough 429 00:27:06,400 --> 00:27:11,400 Speaker 1: energy to support life as we know it. So it's 430 00:27:11,400 --> 00:27:13,600 Speaker 1: depend upon a lot of factors. In the case of 431 00:27:13,680 --> 00:27:18,359 Speaker 1: Kepler one six f the host star is older than 432 00:27:18,560 --> 00:27:23,920 Speaker 1: our son, it is more red, and it's cooler. And 433 00:27:23,960 --> 00:27:26,920 Speaker 1: this also means that if there is in fact life 434 00:27:27,040 --> 00:27:32,119 Speaker 1: on Kepler six F, it probably looks different from life 435 00:27:32,160 --> 00:27:35,400 Speaker 1: on our planet. It's receiving a lot of red wavelength 436 00:27:35,400 --> 00:27:39,359 Speaker 1: photons coming in, which could mean that the plants themselves 437 00:27:39,440 --> 00:27:43,280 Speaker 1: might look very different. They might be big red plants 438 00:27:43,880 --> 00:27:47,520 Speaker 1: all over F or it could be a barren waste land. 439 00:27:47,560 --> 00:27:50,200 Speaker 1: We don't know. We have no way of telling yet. 440 00:27:50,440 --> 00:27:53,480 Speaker 1: We can just make some guesses based upon the age 441 00:27:53,480 --> 00:27:56,760 Speaker 1: of the star, the size of the star, the distance 442 00:27:56,800 --> 00:27:59,920 Speaker 1: that we estimate the planet is from that star, those 443 00:28:00,040 --> 00:28:01,480 Speaker 1: sort of things. Those are the kind of things that 444 00:28:01,560 --> 00:28:06,560 Speaker 1: we can kind of start to draw some basic guesses around. 445 00:28:06,720 --> 00:28:09,480 Speaker 1: But there's still guesses until we can develop some other 446 00:28:09,560 --> 00:28:14,280 Speaker 1: means of really looking at these distant planets. Now, out 447 00:28:14,320 --> 00:28:19,840 Speaker 1: of all the one thousand two four planets announced by 448 00:28:19,960 --> 00:28:25,080 Speaker 1: this research team, nine of those are considered potentially habitable, 449 00:28:25,720 --> 00:28:29,160 Speaker 1: meaning that they are relatively the same size as Earth 450 00:28:29,760 --> 00:28:32,080 Speaker 1: or no greater than two times the size of Earth, 451 00:28:32,760 --> 00:28:40,080 Speaker 1: and within their host stars Goldilocks zone. Now, what's really 452 00:28:40,080 --> 00:28:43,440 Speaker 1: cool is to look at how they determined this, Like 453 00:28:43,480 --> 00:28:48,000 Speaker 1: what was the way that they verified these planets and 454 00:28:48,160 --> 00:28:52,760 Speaker 1: they used a probabilistic approach, meaning what is the probability 455 00:28:52,800 --> 00:28:56,320 Speaker 1: that any given signal is in fact a planet? Essentially, 456 00:28:56,400 --> 00:29:00,240 Speaker 1: they were looking at two main factors. How much does 457 00:29:00,280 --> 00:29:03,760 Speaker 1: a single transit signal resemble what we would expect from 458 00:29:03,760 --> 00:29:07,880 Speaker 1: a transitting planet, so does it look like what a 459 00:29:07,920 --> 00:29:09,960 Speaker 1: planet would look like when passing in front of a star. 460 00:29:11,360 --> 00:29:15,200 Speaker 1: And then also what is the likelihood that that particular 461 00:29:15,240 --> 00:29:18,720 Speaker 1: signal could have been caused by an impostor? And you 462 00:29:18,760 --> 00:29:23,160 Speaker 1: take these two ideas into account and you try to 463 00:29:23,240 --> 00:29:25,800 Speaker 1: figure out what is the likelihood that we have and 464 00:29:26,000 --> 00:29:31,160 Speaker 1: a real legitimate hit here. One of the people associated 465 00:29:31,240 --> 00:29:35,440 Speaker 1: with this mission, Timothy Morton, who's an associate research scholar 466 00:29:35,480 --> 00:29:39,440 Speaker 1: at Princeton University, calculate the probability that any given transit 467 00:29:39,480 --> 00:29:43,920 Speaker 1: signal is actually a planet. Uh by using this and 468 00:29:43,920 --> 00:29:47,479 Speaker 1: and essentially you've got numbers between zero and one, and 469 00:29:47,560 --> 00:29:49,520 Speaker 1: only the results that were as close to one as 470 00:29:49,520 --> 00:29:54,600 Speaker 1: possible better than in fact were kept and verified as 471 00:29:54,600 --> 00:29:58,080 Speaker 1: a planet. Now, the big advantage of this approach is 472 00:29:58,080 --> 00:30:02,440 Speaker 1: that it can be applied to many signals simultaneously. Instead 473 00:30:02,440 --> 00:30:07,400 Speaker 1: of having to continuously review the data of a single 474 00:30:07,520 --> 00:30:11,920 Speaker 1: signal and look for those replicable results. You could take 475 00:30:11,960 --> 00:30:16,640 Speaker 1: this approach and apply it across multiple planets all at 476 00:30:16,680 --> 00:30:19,239 Speaker 1: the same time and see which one's come out at 477 00:30:19,280 --> 00:30:23,160 Speaker 1: greater than certainty. Or as Morton said, if you drop 478 00:30:23,200 --> 00:30:25,520 Speaker 1: a few large crumbs on the floor, you can pick 479 00:30:25,560 --> 00:30:27,360 Speaker 1: those up one by one, but if you spell a 480 00:30:27,360 --> 00:30:31,120 Speaker 1: whole bag of tiny crumbs, you're gonna need a broom. 481 00:30:31,160 --> 00:30:37,280 Speaker 1: And the statistical analysis approach is their broom. So we've 482 00:30:37,320 --> 00:30:42,400 Speaker 1: got out of all the different planets found, about five 483 00:30:42,880 --> 00:30:46,680 Speaker 1: fifty of the one hundred and eighty four were announced 484 00:30:46,720 --> 00:30:50,959 Speaker 1: on May, about five fifty of them might be rocky 485 00:30:51,000 --> 00:30:53,440 Speaker 1: planets like Earth, and out of those only nine are 486 00:30:53,520 --> 00:30:57,360 Speaker 1: considered to occupy the habitable zone. And he might think, well, 487 00:30:57,360 --> 00:31:00,560 Speaker 1: that's a really small number. Nine how many were there before? 488 00:31:00,960 --> 00:31:04,120 Speaker 1: The answer was twelve, So there were a dozen discovered 489 00:31:04,200 --> 00:31:07,520 Speaker 1: before this announcement. Nine more added to it, for a 490 00:31:07,520 --> 00:31:10,840 Speaker 1: total of twenty one. There are several others that are 491 00:31:11,000 --> 00:31:15,440 Speaker 1: possible candidates for rocky like planets that could be in 492 00:31:15,440 --> 00:31:19,800 Speaker 1: the Goldilocks zone, but they don't meet that criteria of yet, 493 00:31:20,400 --> 00:31:23,400 Speaker 1: so they have not been verified. There has just been 494 00:31:23,440 --> 00:31:28,880 Speaker 1: twenty one verified planets that are of rocky most likely 495 00:31:28,880 --> 00:31:36,640 Speaker 1: anyway rocky consistency and in that Goldilocks zone. So this 496 00:31:36,720 --> 00:31:39,760 Speaker 1: is also we gotta remember based on that assumption that 497 00:31:39,800 --> 00:31:43,120 Speaker 1: liquid water is ne necessary prerequisite. If it's not, then 498 00:31:43,120 --> 00:31:46,320 Speaker 1: obviously we could be looking at lots of different plants 499 00:31:46,360 --> 00:31:49,160 Speaker 1: that could potentially support life, might not be life that 500 00:31:49,200 --> 00:31:53,600 Speaker 1: we would recognize. However, so the kepler, as awesome as 501 00:31:53,640 --> 00:31:59,520 Speaker 1: it is, cannot detect all the exoplanets orbiting stars. If 502 00:31:59,560 --> 00:32:03,360 Speaker 1: the planet orbit isn't at the right angle from our perspective, 503 00:32:03,400 --> 00:32:08,240 Speaker 1: from the kepler's perspective, it won't detect any dimming. In 504 00:32:08,280 --> 00:32:10,640 Speaker 1: other words, if there's a planet crossing that star, but 505 00:32:10,680 --> 00:32:13,880 Speaker 1: it's at an angle that does not go in front 506 00:32:13,960 --> 00:32:17,920 Speaker 1: of the star from our perspective, the star doesn't dim, 507 00:32:17,960 --> 00:32:21,000 Speaker 1: we don't see any change in that, and the kepler 508 00:32:21,080 --> 00:32:24,120 Speaker 1: can't detect it. So how many plants are actually passing 509 00:32:24,200 --> 00:32:27,720 Speaker 1: at the correct angle for kepler to detect them well. 510 00:32:27,760 --> 00:32:29,720 Speaker 1: The probability of such a thing is determined by the 511 00:32:29,760 --> 00:32:33,120 Speaker 1: diameter of the star divided by the diameter of the orbit, 512 00:32:33,280 --> 00:32:35,960 Speaker 1: which for a planet the size of Earth orbiting a 513 00:32:36,000 --> 00:32:39,640 Speaker 1: star similar to the Sun eventually gives you a point 514 00:32:39,680 --> 00:32:43,360 Speaker 1: five pc chance of detecting that signal. Being at the 515 00:32:43,480 --> 00:32:48,640 Speaker 1: right angle to detect that signal point five half a 516 00:32:48,720 --> 00:32:52,360 Speaker 1: percent chance of detecting the signal in the first place. 517 00:32:52,600 --> 00:32:56,040 Speaker 1: Bigger plants have a better probability because they are more 518 00:32:56,120 --> 00:32:59,840 Speaker 1: likely to at least pass over a star partially to 519 00:33:00,400 --> 00:33:03,600 Speaker 1: you know, they have fewer angles where you won't see 520 00:33:03,640 --> 00:33:06,920 Speaker 1: anything at all, So a much bigger planet like something 521 00:33:06,960 --> 00:33:09,600 Speaker 1: like Jupiter could be closer to a ten pc chance. 522 00:33:10,360 --> 00:33:13,720 Speaker 1: So it's entirely possible, and even probable in fact, that 523 00:33:14,000 --> 00:33:16,480 Speaker 1: what we have detected is just a tiny fraction of 524 00:33:16,520 --> 00:33:18,800 Speaker 1: what is actually out there, even just with the one 525 00:33:18,840 --> 00:33:22,000 Speaker 1: hundred thousand or so stars we've looked at, more like 526 00:33:22,000 --> 00:33:25,320 Speaker 1: a hundred fifty thousand. But even though we've looked at 527 00:33:25,320 --> 00:33:27,840 Speaker 1: a hundred fifty thousand stars and we've detected so many 528 00:33:27,880 --> 00:33:29,920 Speaker 1: of these exoplanets so far, there could be a lot 529 00:33:30,080 --> 00:33:32,960 Speaker 1: more that we just can't see because of the angle. 530 00:33:33,920 --> 00:33:37,760 Speaker 1: And then you take into account we're looking at a 531 00:33:37,800 --> 00:33:41,480 Speaker 1: hundred thousand out of a hundred billion, and the mind 532 00:33:41,560 --> 00:33:45,840 Speaker 1: really starts to boggle. We realize that the frequency of 533 00:33:45,920 --> 00:33:49,880 Speaker 1: planets around other stars is much greater than we anticipated, 534 00:33:50,720 --> 00:33:55,120 Speaker 1: and that we even maybe looking at more planets in 535 00:33:55,160 --> 00:33:57,880 Speaker 1: the Milky Way than there are stars. So if you 536 00:33:57,920 --> 00:34:00,080 Speaker 1: have a hundred billion stars and there's more in a 537 00:34:00,160 --> 00:34:05,280 Speaker 1: hundred billion planets, you think, wow, the odds of you know, 538 00:34:05,480 --> 00:34:09,560 Speaker 1: the chances that there is another planet within our galaxy 539 00:34:09,640 --> 00:34:13,120 Speaker 1: that could potentially support life are pretty good. It may 540 00:34:13,160 --> 00:34:15,440 Speaker 1: not be anywhere close to us. It may be on 541 00:34:15,440 --> 00:34:17,879 Speaker 1: the other side of the Milky Way galaxy from where 542 00:34:17,880 --> 00:34:20,560 Speaker 1: we are, but the chances are pretty good that there's 543 00:34:20,680 --> 00:34:25,399 Speaker 1: at least some other planets within our own galaxy, let 544 00:34:25,440 --> 00:34:28,839 Speaker 1: alone the universe, which is filled with billions of galaxies. 545 00:34:29,600 --> 00:34:33,239 Speaker 1: And suddenly you think, there's no way that we're the 546 00:34:33,280 --> 00:34:39,120 Speaker 1: only life forms in the universe. That's just not statistically plausible. 547 00:34:40,160 --> 00:34:45,440 Speaker 1: Is it possible? Well, I mean, technically I guess so, 548 00:34:45,880 --> 00:34:51,200 Speaker 1: but it's certainly not not plausible. It's more likely that 549 00:34:51,239 --> 00:34:55,120 Speaker 1: there's life on lots of other planets. Whether it's evolved 550 00:34:55,239 --> 00:34:59,800 Speaker 1: life that is intelligent, that's another matter. Whether it's life 551 00:34:59,800 --> 00:35:03,120 Speaker 1: that is anywhere remotely close to us where we would 552 00:35:03,120 --> 00:35:08,800 Speaker 1: ever have an opportunity to discover it through communication, that's 553 00:35:09,920 --> 00:35:14,560 Speaker 1: highly debatable. Uh, it's quite possible that any any life 554 00:35:14,600 --> 00:35:17,080 Speaker 1: that's that advanced is so far away from us that 555 00:35:17,239 --> 00:35:21,600 Speaker 1: we haven't had enough time to pass for any communication 556 00:35:22,000 --> 00:35:25,200 Speaker 1: generated by that civilization to get to us, because I 557 00:35:25,200 --> 00:35:27,279 Speaker 1: remember that stuff has to travel at the speed of light. 558 00:35:27,320 --> 00:35:31,120 Speaker 1: That's as fast as you can go barring some huge 559 00:35:31,320 --> 00:35:37,040 Speaker 1: change in physics, and so if you are thousands of 560 00:35:37,120 --> 00:35:39,640 Speaker 1: light years away, it's going to take thousands of years 561 00:35:39,640 --> 00:35:41,680 Speaker 1: from the generation of a signal for it to get 562 00:35:41,719 --> 00:35:45,919 Speaker 1: to its destination. And by then the milk has gone bad, 563 00:35:46,239 --> 00:35:49,840 Speaker 1: and that shopping list that the aliens gave us is 564 00:35:49,880 --> 00:35:52,200 Speaker 1: not really going to do anyone any good. The party 565 00:35:52,360 --> 00:35:56,160 Speaker 1: is over, but still it's really exciting to think about 566 00:35:56,200 --> 00:35:59,160 Speaker 1: what the Kepler telescope has done. Now, keep in mind 567 00:35:59,239 --> 00:36:01,560 Speaker 1: this is very different from other types of telescopes. There 568 00:36:01,560 --> 00:36:05,480 Speaker 1: are other ways of detecting the potential for exoplanets. One 569 00:36:05,520 --> 00:36:07,880 Speaker 1: of those is to look at stars and look to 570 00:36:07,960 --> 00:36:11,439 Speaker 1: see if they are moving at all, like if there's 571 00:36:11,440 --> 00:36:14,319 Speaker 1: a little jiggle, which could indicate that there is a 572 00:36:14,320 --> 00:36:17,799 Speaker 1: gravitational pull upon that star, and that in turn can 573 00:36:17,840 --> 00:36:20,160 Speaker 1: indicate that there is a planet in orbit around the 574 00:36:20,200 --> 00:36:23,440 Speaker 1: start and the planet's gravitational pull in the star is 575 00:36:23,480 --> 00:36:26,880 Speaker 1: causing it to move just a little bit, and that 576 00:36:26,920 --> 00:36:29,759 Speaker 1: we can detect that. That's another way of detecting at 577 00:36:29,800 --> 00:36:33,800 Speaker 1: least the potential of an exo planet in that star's orbit, 578 00:36:34,920 --> 00:36:38,560 Speaker 1: but it's different obviously from the transit method. And then 579 00:36:38,560 --> 00:36:40,960 Speaker 1: there are ways where we can look at planets to 580 00:36:41,000 --> 00:36:44,360 Speaker 1: try and determine what are they made of, and we 581 00:36:44,480 --> 00:36:47,439 Speaker 1: usually use a spectroscopy for that, where we we take 582 00:36:47,640 --> 00:36:52,239 Speaker 1: the light reflected off of a planet and we analyze 583 00:36:52,280 --> 00:36:54,839 Speaker 1: that light and we break it down into the various wavelengths, 584 00:36:55,239 --> 00:36:58,320 Speaker 1: and then we start to make very educated guesses about 585 00:36:58,360 --> 00:37:03,120 Speaker 1: the types of elements that are present on that particular planet. 586 00:37:03,760 --> 00:37:09,280 Speaker 1: Even so, this is still largely working from very educated guesses, 587 00:37:10,040 --> 00:37:14,279 Speaker 1: uh so educated that you could argue they are they 588 00:37:14,280 --> 00:37:17,640 Speaker 1: are as good as fact, at least in some cases. 589 00:37:17,719 --> 00:37:19,600 Speaker 1: But you have to keep in mind there's still there's 590 00:37:19,600 --> 00:37:22,920 Speaker 1: still a tiny room for error. So that about wraps 591 00:37:22,920 --> 00:37:25,640 Speaker 1: it up for the Kepler Telescope. It has served us well. 592 00:37:26,040 --> 00:37:30,040 Speaker 1: It's primary mission is over um. We will continue to 593 00:37:30,120 --> 00:37:33,320 Speaker 1: look at the data from the Kepler Telescope for many 594 00:37:33,400 --> 00:37:38,000 Speaker 1: more years, but the actual data gathering portion of the 595 00:37:38,080 --> 00:37:41,680 Speaker 1: Kepler's life is over. There are other telescopes that we're 596 00:37:41,719 --> 00:37:44,560 Speaker 1: planning on launching that will continue this work. It will 597 00:37:44,600 --> 00:37:48,360 Speaker 1: either be looking for similar planets to what Kepler was 598 00:37:48,400 --> 00:37:52,560 Speaker 1: looking for or different style planets. But we're just getting started, 599 00:37:52,640 --> 00:37:55,640 Speaker 1: and the hope is that we will eventually be able 600 00:37:55,719 --> 00:37:59,640 Speaker 1: to draw some very firm conclusions about the presence of 601 00:37:59,760 --> 00:38:02,000 Speaker 1: life within our galaxy, and this could just be the 602 00:38:02,040 --> 00:38:04,720 Speaker 1: first step toward that. So while a lot of those 603 00:38:04,800 --> 00:38:09,520 Speaker 1: news outlets were perhaps being a bit optimistic about the 604 00:38:09,560 --> 00:38:14,280 Speaker 1: announcement of the discovery of alien life, it is true 605 00:38:14,320 --> 00:38:18,520 Speaker 1: that this is a step toward making such a discovery, 606 00:38:18,719 --> 00:38:21,480 Speaker 1: and it may be many, many, many more decades before 607 00:38:21,520 --> 00:38:25,600 Speaker 1: we're able to say, yes, we've detected the presence of 608 00:38:25,680 --> 00:38:30,680 Speaker 1: life on another planet. But it's through work like the 609 00:38:30,800 --> 00:38:33,560 Speaker 1: Kepler mission that will get there. So this is a 610 00:38:33,640 --> 00:38:38,320 Speaker 1: really cool science and technology story, and I just wanted 611 00:38:38,320 --> 00:38:40,440 Speaker 1: to touch on that because I loved that announcement. I 612 00:38:40,440 --> 00:38:43,279 Speaker 1: actually listened to it live while they were talking about 613 00:38:43,360 --> 00:38:46,319 Speaker 1: and it was just really cool to hear a group 614 00:38:46,360 --> 00:38:50,040 Speaker 1: of engineers and scientists talk about their life's work with 615 00:38:50,080 --> 00:38:55,120 Speaker 1: such passion. So, guys, if you have suggestions for future 616 00:38:55,200 --> 00:38:58,000 Speaker 1: episodes of Tech Stuff or you've got questions or comments 617 00:38:58,040 --> 00:39:00,279 Speaker 1: or anything like that. Maybe you've got a suggest stution 618 00:39:00,320 --> 00:39:03,400 Speaker 1: for a future guest host or an interview subject. Let 619 00:39:03,440 --> 00:39:07,480 Speaker 1: me know. Send me an email. The address is tech 620 00:39:07,600 --> 00:39:11,400 Speaker 1: stuff at how stuff works dot com, or drop me 621 00:39:11,440 --> 00:39:14,600 Speaker 1: a line on Facebook or Twitter. The handle at both 622 00:39:14,640 --> 00:39:18,799 Speaker 1: of those is tech stuff hs W and I will 623 00:39:18,800 --> 00:39:26,319 Speaker 1: talk to you again really soon. For more on this 624 00:39:26,480 --> 00:39:29,000 Speaker 1: and bousands of other topics. Is it how stuff works 625 00:39:29,000 --> 00:39:39,200 Speaker 1: dot com