1 00:00:08,240 --> 00:00:04,280 so sorry for the delay welcome to the 2 00:00:10,339 --> 00:00:08,250 astrobiology seminars we're not having a 3 00:00:12,709 --> 00:00:10,349 full series this quarter we will have 4 00:00:14,780 --> 00:00:12,719 one in the spring quarter but we are 5 00:00:16,099 --> 00:00:14,790 going to be having three candidate 6 00:00:19,490 --> 00:00:16,109 business this is the first of them for 7 00:00:21,590 --> 00:00:19,500 the astrobiology faculty position Vicki 8 00:00:23,090 --> 00:00:21,600 if she came here we'd be both in 9 00:00:26,540 --> 00:00:23,100 astrobiology and sitting in the 10 00:00:27,950 --> 00:00:26,550 Astronomy Department so we're really 11 00:00:31,910 --> 00:00:27,960 working here because you gave a talk to 12 00:00:33,200 --> 00:00:31,920 be strongly Department just 12 30 so 13 00:00:35,900 --> 00:00:33,210 we're hoping over her voice will hold 14 00:00:37,940 --> 00:00:35,910 out but Vicki got her PhD in 1994 at 15 00:00:39,260 --> 00:00:37,950 Sydney University where she was a 16 00:00:41,810 --> 00:00:39,270 student of David Allen one of the 17 00:00:45,410 --> 00:00:41,820 pioneers of down based infrared 18 00:00:47,590 --> 00:00:45,420 astronomy and she came to JPL after that 19 00:00:50,660 --> 00:00:47,600 and has been in the States ever since 20 00:00:53,389 --> 00:00:50,670 primarily working on Venus but other 21 00:00:54,860 --> 00:00:53,399 solar system projects too and we've 22 00:00:57,580 --> 00:00:54,870 noted very well in the astrobiology 23 00:01:00,860 --> 00:00:57,590 program because she has been one of the 24 00:01:02,420 --> 00:01:00,870 leaders of the so called nodes or 25 00:01:05,030 --> 00:01:02,430 research groups that the NASA 26 00:01:07,130 --> 00:01:05,040 astrobiologist who has sponsored over 27 00:01:09,410 --> 00:01:07,140 the years just as it has here at the UW 28 00:01:11,300 --> 00:01:09,420 and so she's calling that we've known 29 00:01:13,730 --> 00:01:11,310 for many years and we're delighted to 30 00:01:16,760 --> 00:01:13,740 have her here for this visit and for 31 00:01:19,280 --> 00:01:16,770 anything she's going to be talking about 32 00:01:21,890 --> 00:01:19,290 what that nose is all about the virtual 33 00:01:24,140 --> 00:01:21,900 planetary laboratory which is a 34 00:01:26,090 --> 00:01:24,150 marvelous simulation of what other 35 00:01:27,440 --> 00:01:26,100 terrestrial planets might look like to 36 00:01:31,190 --> 00:01:27,450 something like the terrestrial planet 37 00:01:32,960 --> 00:01:31,200 finder so particularly thank you okay so 38 00:01:36,859 --> 00:01:32,970 thank you all for coming and especially 39 00:01:39,140 --> 00:01:36,869 those on webex virtually as well hi so 40 00:01:40,730 --> 00:01:39,150 now my name is dr. Vickie meadows I was 41 00:01:43,130 --> 00:01:40,740 the principal investigator for the 42 00:01:45,410 --> 00:01:43,140 virtual planetary league team which we 43 00:01:46,940 --> 00:01:45,420 now call an alumni team or a former 44 00:01:49,999 --> 00:01:46,950 member of the nasa astrobiology 45 00:01:51,830 --> 00:01:50,009 institute and we are 40 people at a 46 00:01:54,109 --> 00:01:51,840 total of eighteen different institutions 47 00:01:56,510 --> 00:01:54,119 so this not more than two or three of us 48 00:01:57,859 --> 00:01:56,520 with any given institution and but 49 00:02:00,289 --> 00:01:57,869 nonetheless we managed to collaborate 50 00:02:03,170 --> 00:02:00,299 virtually by email and and meetings and 51 00:02:05,719 --> 00:02:03,180 visitor collaborations so what I'm going 52 00:02:07,760 --> 00:02:05,729 to talk to you today about of four major 53 00:02:09,889 --> 00:02:07,770 topics first I'm going to review 54 00:02:11,630 --> 00:02:09,899 so-called habitability markers and bio 55 00:02:12,130 --> 00:02:11,640 signatures what we would look for in the 56 00:02:13,900 --> 00:02:12,140 spectrum 57 00:02:14,920 --> 00:02:13,910 planta de Renner to the star to try and 58 00:02:17,199 --> 00:02:14,930 understand what its planetary 59 00:02:18,790 --> 00:02:17,209 environment is like I'm then going to 60 00:02:21,160 --> 00:02:18,800 talk about work that we've done already 61 00:02:22,990 --> 00:02:21,170 on taking earth ripping away the Sun 62 00:02:25,090 --> 00:02:23,000 throwing it away and replacing it with 63 00:02:27,309 --> 00:02:25,100 some other type of star and looking at 64 00:02:29,110 --> 00:02:27,319 how the Earth's atmosphere would respond 65 00:02:31,690 --> 00:02:29,120 to the different radiation that's coming 66 00:02:33,550 --> 00:02:31,700 in and what that does to fix me a 67 00:02:35,800 --> 00:02:33,560 massacre and the spectrum of the planet 68 00:02:37,630 --> 00:02:35,810 I'm going to also talk about new work 69 00:02:40,000 --> 00:02:37,640 that we've done on hike high carbon 70 00:02:42,010 --> 00:02:40,010 dioxide early Earth's are specifically 71 00:02:44,410 --> 00:02:42,020 looking to try and produce oxygen from 72 00:02:46,570 --> 00:02:44,420 these atmospheres by doing all sorts of 73 00:02:49,420 --> 00:02:46,580 things adding UV radiation vulcanism 74 00:02:50,770 --> 00:02:49,430 various different things and I'll show 75 00:02:53,050 --> 00:02:50,780 you some of the results from that and 76 00:02:55,030 --> 00:02:53,060 what we found and finally I'm going to 77 00:02:57,490 --> 00:02:55,040 cap off with some very new work that's 78 00:03:00,160 --> 00:02:57,500 coming out in march on extrasolar 79 00:03:02,140 --> 00:03:00,170 photosynthesis and trying to understand 80 00:03:03,940 --> 00:03:02,150 what the preferential pigments for 81 00:03:06,250 --> 00:03:03,950 photosynthesis would be like on planets 82 00:03:09,400 --> 00:03:06,260 around other stars by looking at the 83 00:03:11,199 --> 00:03:09,410 places in the spectrum of radiation on 84 00:03:12,520 --> 00:03:11,209 the surface of the planet where a plant 85 00:03:17,170 --> 00:03:12,530 would really get the best value for 86 00:03:20,020 --> 00:03:17,180 photosynthesis and first of all if you 87 00:03:22,300 --> 00:03:20,030 like to talk vinit I usually take like 88 00:03:24,340 --> 00:03:22,310 to begin these hooks by talking about 89 00:03:26,229 --> 00:03:24,350 the fact that the planets that we find 90 00:03:28,449 --> 00:03:26,239 the extra solar terrestrial planets even 91 00:03:29,800 --> 00:03:28,459 though we've never detected one yet it's 92 00:03:31,870 --> 00:03:29,810 highly probable that they're going to be 93 00:03:33,699 --> 00:03:31,880 very different to the three examples of 94 00:03:36,069 --> 00:03:33,709 terrestrial planets with the atmospheres 95 00:03:37,660 --> 00:03:36,079 that we have in our own solar system so 96 00:03:39,100 --> 00:03:37,670 when we talk about you know learning 97 00:03:40,750 --> 00:03:39,110 about what these might be like or how to 98 00:03:42,850 --> 00:03:40,760 characterize them we have to keep in 99 00:03:45,640 --> 00:03:42,860 mind that these planets are likely to be 100 00:03:47,590 --> 00:03:45,650 very alien and they may span a range of 101 00:03:50,890 --> 00:03:47,600 characteristics that's just not seen in 102 00:03:52,690 --> 00:03:50,900 our own planetary system so to get a 103 00:03:54,759 --> 00:03:52,700 handle on what these might be like we 104 00:03:56,530 --> 00:03:54,769 really do have to resort to modeling we 105 00:03:58,240 --> 00:03:56,540 don't yet have the observations we've 106 00:03:59,890 --> 00:03:58,250 got a few examples in our solar system 107 00:04:01,630 --> 00:03:59,900 but it really is modeling that will 108 00:04:04,270 --> 00:04:01,640 allow us to push that face spaced out 109 00:04:05,830 --> 00:04:04,280 and explore in a virtual way what these 110 00:04:08,259 --> 00:04:05,840 planets might be like and what we might 111 00:04:10,509 --> 00:04:08,269 expect to see so that the plot that we 112 00:04:13,930 --> 00:04:10,519 have up here planetary system diversity 113 00:04:15,789 --> 00:04:13,940 Marco is show some of the results from 114 00:04:18,640 --> 00:04:15,799 the Raymond Quinn and lunin modeling of 115 00:04:20,650 --> 00:04:18,650 different types of planetary systems so 116 00:04:22,029 --> 00:04:20,660 these are planet formation models and 117 00:04:23,650 --> 00:04:22,039 what they show is a whole series of 118 00:04:25,750 --> 00:04:23,660 colored dots here which represent 119 00:04:27,400 --> 00:04:25,760 planets where the color is 120 00:04:29,920 --> 00:04:27,410 the volatile abundance and in particular 121 00:04:31,930 --> 00:04:29,930 water abundance in the planet where blue 122 00:04:34,690 --> 00:04:31,940 is very water rich red is very water 123 00:04:37,930 --> 00:04:34,700 poor and the black circles donate the 124 00:04:39,550 --> 00:04:37,940 iron fraction in the planet so you can 125 00:04:41,770 --> 00:04:39,560 see in these plots the semi-major axis 126 00:04:43,810 --> 00:04:41,780 is plotted on the bottom so that's the 127 00:04:46,030 --> 00:04:43,820 distance from its parent star and then 128 00:04:49,300 --> 00:04:46,040 the e centricity how much it varies from 129 00:04:51,280 --> 00:04:49,310 a circle is plotted on the y-axis so in 130 00:04:53,050 --> 00:04:51,290 these planetary models they do make a 131 00:04:55,270 --> 00:04:53,060 menagerie of different types of planets 132 00:04:57,580 --> 00:04:55,280 with varying abundances of water are 133 00:04:59,920 --> 00:04:57,590 different to the earth Venus and Mars in 134 00:05:01,840 --> 00:04:59,930 our own case and so we anticipate that 135 00:05:03,700 --> 00:05:01,850 when we go out and look with something 136 00:05:05,200 --> 00:05:03,710 like the terrestrial planet finder that 137 00:05:07,030 --> 00:05:05,210 we're going to find really strange and 138 00:05:08,860 --> 00:05:07,040 wonderful things and so the virtual 139 00:05:10,570 --> 00:05:08,870 planetary laboratory as i said is trying 140 00:05:14,710 --> 00:05:10,580 to explore what those strange wonderful 141 00:05:16,810 --> 00:05:14,720 things might look like so when we 142 00:05:19,030 --> 00:05:16,820 remotely detect our planet around 143 00:05:20,910 --> 00:05:19,040 another star it's going to be unresolved 144 00:05:23,290 --> 00:05:20,920 we're not going to be able to see 145 00:05:25,060 --> 00:05:23,300 spatial information on it we won't be 146 00:05:26,830 --> 00:05:25,070 able to see continents or clouds or 147 00:05:29,610 --> 00:05:26,840 oceans directly in our astronomical 148 00:05:32,710 --> 00:05:29,620 images it will look like a pixel and 149 00:05:34,800 --> 00:05:32,720 hopefully a nice blue pixel by pixel is 150 00:05:37,000 --> 00:05:34,810 pretty much all we're going to get so 151 00:05:38,740 --> 00:05:37,010 everything we learn about this planet 152 00:05:41,560 --> 00:05:38,750 must be obtained from what we call disc 153 00:05:44,200 --> 00:05:41,570 average data so the the disc of the 154 00:05:45,940 --> 00:05:44,210 planet is essentially squished down no 155 00:05:48,430 --> 00:05:45,950 spatial resolution but we can get 156 00:05:51,130 --> 00:05:48,440 spectral resolution so we have a disc 157 00:05:53,470 --> 00:05:51,140 averaged observation of the planet but 158 00:05:57,150 --> 00:05:53,480 at different wavelengths and from that 159 00:05:59,560 --> 00:05:57,160 we have to draw it try and decompose 160 00:06:03,520 --> 00:05:59,570 what the planet is like whether it has 161 00:06:05,290 --> 00:06:03,530 oceans or clouds or different types of 162 00:06:09,280 --> 00:06:05,300 surface features where time steps are 163 00:06:11,650 --> 00:06:09,290 not working here so sorry about that so 164 00:06:12,880 --> 00:06:11,660 in essence not only do we have to 165 00:06:14,290 --> 00:06:12,890 understand the environment from the disc 166 00:06:16,360 --> 00:06:14,300 average but whether or not there is life 167 00:06:18,880 --> 00:06:16,370 on it must also be determined from this 168 00:06:20,860 --> 00:06:18,890 disc average so the signs of life must 169 00:06:22,420 --> 00:06:20,870 be a global phenomenon on this planet or 170 00:06:25,300 --> 00:06:22,430 we really don't have a very good chance 171 00:06:27,280 --> 00:06:25,310 of detecting them so when we talk about 172 00:06:29,170 --> 00:06:27,290 the habitability zone when we look at 173 00:06:30,700 --> 00:06:29,180 planets around other stars we're really 174 00:06:32,860 --> 00:06:30,710 talking about what we call a classic 175 00:06:34,519 --> 00:06:32,870 habitability zone which is the range at 176 00:06:36,799 --> 00:06:34,529 which liquid water can remain 177 00:06:39,259 --> 00:06:36,809 so sorry the water can remain liquid on 178 00:06:41,179 --> 00:06:39,269 the surface of the planet and I know 179 00:06:42,559 --> 00:06:41,189 that a lot of people here work on Europa 180 00:06:44,299 --> 00:06:42,569 and other types of environments that are 181 00:06:46,099 --> 00:06:44,309 outside of this classic habitable zone 182 00:06:47,749 --> 00:06:46,109 where none nonetheless life may be 183 00:06:50,209 --> 00:06:47,759 possible but these would be very 184 00:06:52,999 --> 00:06:50,219 difficult to detect remotely so we don't 185 00:06:56,899 --> 00:06:53,009 include them in our definition of a 186 00:06:58,399 --> 00:06:56,909 habitable zone region so I also want to 187 00:06:59,869 --> 00:06:58,409 say that when we try and characterize 188 00:07:02,149 --> 00:06:59,879 the planet and learn about it our 189 00:07:03,739 --> 00:07:02,159 ability to do that will only be as good 190 00:07:05,719 --> 00:07:03,749 as the effective emitting layer of the 191 00:07:08,149 --> 00:07:05,729 planet so essentially at the wavelengths 192 00:07:09,979 --> 00:07:08,159 that we choose how far we can penetrate 193 00:07:12,229 --> 00:07:09,989 into the planet's atmosphere is is all 194 00:07:13,399 --> 00:07:12,239 we're going to get so if the planet for 195 00:07:15,709 --> 00:07:13,409 example is completely covered with 196 00:07:18,049 --> 00:07:15,719 clouds as Venus's and we observe in the 197 00:07:20,029 --> 00:07:18,059 visible and we can only characterize the 198 00:07:21,829 --> 00:07:20,039 the atmosphere above the clouds and 199 00:07:23,179 --> 00:07:21,839 that's all we will have so there will be 200 00:07:25,009 --> 00:07:23,189 instances where we might find an 201 00:07:26,509 --> 00:07:25,019 extremely interesting planet but we may 202 00:07:28,609 --> 00:07:26,519 not have the capability to actually 203 00:07:30,019 --> 00:07:28,619 probe all the way to the surface to find 204 00:07:31,579 --> 00:07:30,029 out if it can in fact support liquid 205 00:07:32,869 --> 00:07:31,589 water so these are the kind of 206 00:07:35,329 --> 00:07:32,879 challenges we have when trying to 207 00:07:38,179 --> 00:07:35,339 remotely characterize an entire entire 208 00:07:40,009 --> 00:07:38,189 world so the things that we will look 209 00:07:42,139 --> 00:07:40,019 for when we find our terrestrial planet 210 00:07:43,489 --> 00:07:42,149 around another star you know what are 211 00:07:45,679 --> 00:07:43,499 the planetary system environmental 212 00:07:48,139 --> 00:07:45,689 characteristics of course the parent 213 00:07:50,179 --> 00:07:48,149 star like is it a nice parent star is it 214 00:07:52,129 --> 00:07:50,189 fairly stable or is it actively flaring 215 00:07:54,559 --> 00:07:52,139 all the time and being difficult under 216 00:07:56,299 --> 00:07:54,569 other planets in the solar system that 217 00:07:57,469 --> 00:07:56,309 might improve the chances of the planet 218 00:07:59,839 --> 00:07:57,479 that we found being habitable for 219 00:08:02,329 --> 00:07:59,849 example a nice stable Jovian planet in 220 00:08:04,339 --> 00:08:02,339 an outer solar system orbit will also 221 00:08:07,219 --> 00:08:04,349 look for math and orbital parameters and 222 00:08:10,069 --> 00:08:07,229 with the suite of missions that nASA has 223 00:08:11,329 --> 00:08:10,079 planned the best instrumentation for 224 00:08:14,899 --> 00:08:11,339 doing that is something called the space 225 00:08:16,269 --> 00:08:14,909 interferometry mission or sin so sim may 226 00:08:19,369 --> 00:08:16,279 be able to get us mass and orbital 227 00:08:22,009 --> 00:08:19,379 parameters for planets that are a maybe 228 00:08:23,299 --> 00:08:22,019 as as small as three earth masses so we 229 00:08:24,919 --> 00:08:23,309 would like to have that mission to at 230 00:08:26,269 --> 00:08:24,929 least have already gotten us our mass in 231 00:08:27,769 --> 00:08:26,279 orbit before we go after with 232 00:08:29,569 --> 00:08:27,779 terrestrial planet finder to try to get 233 00:08:30,799 --> 00:08:29,579 a spectrum so we will look for 234 00:08:32,689 --> 00:08:30,809 terrestrial planets in the so-called 235 00:08:34,790 --> 00:08:32,699 habitable zone in this classic habitable 236 00:08:36,499 --> 00:08:34,800 zone but to do that we really will have 237 00:08:38,239 --> 00:08:36,509 to have the orbit to know whether it's 238 00:08:40,850 --> 00:08:38,249 circular and a planet stays in the 239 00:08:42,919 --> 00:08:40,860 habitable zone or whether it's eccentric 240 00:08:43,510 --> 00:08:42,929 and there may be slight excursions from 241 00:08:45,490 --> 00:08:43,520 the habitable 242 00:08:47,920 --> 00:08:45,500 but it's very important to have that 243 00:08:49,510 --> 00:08:47,930 orbital information and terrestrial 244 00:08:52,570 --> 00:08:49,520 planet finder by the way may not be very 245 00:08:54,160 --> 00:08:52,580 good at that so photometric 246 00:08:55,330 --> 00:08:54,170 characteristics is the next thing we 247 00:08:57,970 --> 00:08:55,340 will look for because of course we're 248 00:08:59,590 --> 00:08:57,980 very starved for photons here so we'll 249 00:09:00,880 --> 00:08:59,600 try and look at colors first we'll look 250 00:09:02,770 --> 00:09:00,890 at the brightness and color of the 251 00:09:05,140 --> 00:09:02,780 target so how much radiation is coming 252 00:09:06,430 --> 00:09:05,150 in at different wavelengths and look and 253 00:09:09,460 --> 00:09:06,440 see if there's any temporal variability 254 00:09:11,170 --> 00:09:09,470 that might hint it inhomogeneity and on 255 00:09:12,790 --> 00:09:11,180 the other planet you know whether or not 256 00:09:15,460 --> 00:09:12,800 you've seen continents and clouds and 257 00:09:17,050 --> 00:09:15,470 oceans things moving around and then 258 00:09:18,820 --> 00:09:17,060 finally the most powerful tool that we 259 00:09:20,260 --> 00:09:18,830 have will be spectra and these are the 260 00:09:23,190 --> 00:09:20,270 most difficult observations to get 261 00:09:26,470 --> 00:09:23,200 because we must take already photon poor 262 00:09:28,960 --> 00:09:26,480 ray radiation information and then 263 00:09:30,760 --> 00:09:28,970 disperse it even further but nonetheless 264 00:09:32,410 --> 00:09:30,770 if we can get good spectra of these 265 00:09:34,480 --> 00:09:32,420 planets that's our most powerful tool 266 00:09:35,770 --> 00:09:34,490 for working out what they're like and in 267 00:09:38,500 --> 00:09:35,780 their spectral will look for things like 268 00:09:40,300 --> 00:09:38,510 carbon dioxide which lets me know that I 269 00:09:43,060 --> 00:09:40,310 probably have a terrestrial planet with 270 00:09:45,010 --> 00:09:43,070 an atmosphere it's not common to see a 271 00:09:46,960 --> 00:09:45,020 lot of carbon dioxide in a Jovian planet 272 00:09:49,450 --> 00:09:46,970 around the sphere in fact three planets 273 00:09:51,070 --> 00:09:49,460 we have Venus Earth and Mars all have 274 00:09:52,390 --> 00:09:51,080 strong carbon dioxide absorptions that's 275 00:09:54,880 --> 00:09:52,400 considered characteristic of terrestrial 276 00:09:56,230 --> 00:09:54,890 planet we'll look for water vapor which 277 00:09:58,360 --> 00:09:56,240 may be a good indicator that there's 278 00:09:59,890 --> 00:09:58,370 liquid water on the surface not always 279 00:10:02,050 --> 00:09:59,900 but it's usually a pretty good indicator 280 00:10:03,880 --> 00:10:02,060 that we have it will look for signs that 281 00:10:06,460 --> 00:10:03,890 there's an ultraviolet shield somewhere 282 00:10:07,990 --> 00:10:06,470 in the atmosphere so you look for signs 283 00:10:10,210 --> 00:10:08,000 that there's something we recognized as 284 00:10:12,910 --> 00:10:10,220 a UV shield like ozone our famous ozone 285 00:10:15,160 --> 00:10:12,920 layer so either look directly for ozone 286 00:10:17,140 --> 00:10:15,170 in the spectrum or we will look for what 287 00:10:19,030 --> 00:10:17,150 we call secondary signs of a UV shield 288 00:10:21,580 --> 00:10:19,040 and that is looking for the temperature 289 00:10:23,950 --> 00:10:21,590 effect of ozone in the absorption band 290 00:10:26,320 --> 00:10:23,960 of other molecules so carbon dioxide for 291 00:10:28,300 --> 00:10:26,330 example has a central peak in it which 292 00:10:30,550 --> 00:10:28,310 denotes our hot stratosphere and that 293 00:10:32,590 --> 00:10:30,560 stratosphere is hot because of ozone so 294 00:10:34,060 --> 00:10:32,600 even if we didn't detect ozone we would 295 00:10:35,170 --> 00:10:34,070 look for that hot central peak that says 296 00:10:37,030 --> 00:10:35,180 hey there's something up high in the 297 00:10:38,590 --> 00:10:37,040 atmosphere absorbing UV radiation and 298 00:10:41,710 --> 00:10:38,600 that's a good thing because it protects 299 00:10:43,509 --> 00:10:41,720 the life underneath other potential life 300 00:10:45,249 --> 00:10:43,519 and then of course we will do a spectral 301 00:10:47,590 --> 00:10:45,259 determination o is the longest 302 00:10:49,389 --> 00:10:47,600 wavelength range we possibly can to try 303 00:10:51,069 --> 00:10:49,399 and get a census of what gases are in 304 00:10:52,840 --> 00:10:51,079 the atmosphere and whether they are 305 00:10:55,329 --> 00:10:52,850 greenhouse gases and how much of them 306 00:10:56,710 --> 00:10:55,339 there are because ultimately being able 307 00:10:58,470 --> 00:10:56,720 to measure the surface temperature of 308 00:11:00,699 --> 00:10:58,480 the planet that's the holy grail of 309 00:11:01,990 --> 00:11:00,709 habitability can we determine the 310 00:11:03,069 --> 00:11:02,000 surface temperature and pressure and 311 00:11:05,110 --> 00:11:03,079 know that there's liquid water on the 312 00:11:06,730 --> 00:11:05,120 surface that measurement directly is 313 00:11:08,710 --> 00:11:06,740 highly unlikely what will probably 314 00:11:10,389 --> 00:11:08,720 happen is that we will measure some 315 00:11:12,730 --> 00:11:10,399 temperature we won't know exactly where 316 00:11:14,439 --> 00:11:12,740 in the atmosphere it is but will then 317 00:11:15,999 --> 00:11:14,449 need to know to have a look at these 318 00:11:17,619 --> 00:11:16,009 other gases and their passages to work 319 00:11:20,230 --> 00:11:17,629 out where we might be sampling it and 320 00:11:22,569 --> 00:11:20,240 more importantly to determine how much 321 00:11:24,699 --> 00:11:22,579 greenhouse warming this planet can can 322 00:11:26,889 --> 00:11:24,709 provide to then try and infer the 323 00:11:28,059 --> 00:11:26,899 surface temperature from that so that 324 00:11:32,110 --> 00:11:28,069 service temperature is probably going to 325 00:11:33,910 --> 00:11:32,120 be a model to derived parameter so when 326 00:11:36,280 --> 00:11:33,920 we look at x 0 signatures they fall into 327 00:11:37,629 --> 00:11:36,290 three basic categories first of all the 328 00:11:39,309 --> 00:11:37,639 biasing itches we're looking at and not 329 00:11:40,660 --> 00:11:39,319 like the Institute biosignatures we pick 330 00:11:42,610 --> 00:11:40,670 up a rock and you sample it and try and 331 00:11:44,470 --> 00:11:42,620 tell if it has life in it these are 332 00:11:46,449 --> 00:11:44,480 signs of life that are observable by a 333 00:11:48,790 --> 00:11:46,459 telescope so we call them astronomical 334 00:11:51,369 --> 00:11:48,800 biosignatures and so these have to be 335 00:11:53,110 --> 00:11:51,379 global scale photometric spectral or 336 00:11:56,319 --> 00:11:53,120 temporal features that are indicative of 337 00:11:58,559 --> 00:11:56,329 life that's the three classes so as we 338 00:12:00,610 --> 00:11:58,569 can see in this this upper plot here 339 00:12:01,900 --> 00:12:00,620 life can provide global scale 340 00:12:05,769 --> 00:12:01,910 modification of a planet's atmosphere 341 00:12:08,170 --> 00:12:05,779 and for our own planet oxygen is the the 342 00:12:12,939 --> 00:12:08,180 most obvious marker of that as my 343 00:12:14,740 --> 00:12:12,949 pointer so up here we have a very strong 344 00:12:17,110 --> 00:12:14,750 band of oxygen the oxygen a band in the 345 00:12:18,369 --> 00:12:17,120 in the optical that much oxygen in the 346 00:12:20,259 --> 00:12:18,379 atmosphere is considered to be 347 00:12:22,929 --> 00:12:20,269 indicative of life so that's an 348 00:12:25,329 --> 00:12:22,939 atmospheric bio signature down here we 349 00:12:27,129 --> 00:12:25,339 have a surface bio signature and this is 350 00:12:28,780 --> 00:12:27,139 in fact a spectrum taken down through 351 00:12:30,790 --> 00:12:28,790 the Earth's atmosphere over a conifer 352 00:12:33,069 --> 00:12:30,800 forest and what it shows is a very 353 00:12:34,780 --> 00:12:33,079 characteristic rise in the red at about 354 00:12:38,230 --> 00:12:34,790 point seven microns it's called the red 355 00:12:40,179 --> 00:12:38,240 edge it's a reflective property of 356 00:12:42,280 --> 00:12:40,189 leaves longwood of point seven microns 357 00:12:44,530 --> 00:12:42,290 and so its characteristic of surface 358 00:12:46,119 --> 00:12:44,540 vegetation and that signature can be 359 00:12:47,710 --> 00:12:46,129 seen from space and it can be seen in 360 00:12:49,140 --> 00:12:47,720 the disk average although it's quite 361 00:12:51,150 --> 00:12:49,150 difficult in that 362 00:12:53,160 --> 00:12:51,160 case now the other thing we look at is 363 00:12:54,930 --> 00:12:53,170 are there any changes in the planets 364 00:12:58,200 --> 00:12:54,940 appearance over time that might be 365 00:12:59,760 --> 00:12:58,210 indicative of life cycles and one of 366 00:13:02,370 --> 00:12:59,770 these in our Earth's atmosphere 367 00:13:03,960 --> 00:13:02,380 admittedly very subtle and difficult to 368 00:13:05,250 --> 00:13:03,970 detect but we'd have to try and hope 369 00:13:07,200 --> 00:13:05,260 that maybe on another planet might be 370 00:13:08,760 --> 00:13:07,210 more obvious but in our own Earth's 371 00:13:10,860 --> 00:13:08,770 atmosphere we have the cycling of 372 00:13:12,540 --> 00:13:10,870 methane and carbon dioxide in the 373 00:13:15,720 --> 00:13:12,550 northern atmosphere due to the 374 00:13:18,390 --> 00:13:15,730 production and decay of vegetation in 375 00:13:20,820 --> 00:13:18,400 the northern atmosphere and in fact life 376 00:13:23,180 --> 00:13:20,830 in general so we see this annual cycling 377 00:13:25,170 --> 00:13:23,190 over time for methane and carbon dioxide 378 00:13:27,180 --> 00:13:25,180 but one thing we have to fundamentally 379 00:13:29,160 --> 00:13:27,190 remember as to the people who do 380 00:13:30,810 --> 00:13:29,170 instituto signatures is that to 381 00:13:32,010 --> 00:13:30,820 recognize a bio signature you really 382 00:13:33,930 --> 00:13:32,020 have to have a good idea of the 383 00:13:35,610 --> 00:13:33,940 environment you're studying because bio 384 00:13:38,760 --> 00:13:35,620 students must always be identified in 385 00:13:40,740 --> 00:13:38,770 the context of their environment and for 386 00:13:42,630 --> 00:13:40,750 example earth methane is in an 387 00:13:44,880 --> 00:13:42,640 environment that is very rich in oxygen 388 00:13:46,140 --> 00:13:44,890 and oxygen and methane don't 389 00:13:47,790 --> 00:13:46,150 particularly like each other they don't 390 00:13:49,830 --> 00:13:47,800 hang around long for a long time 391 00:13:51,840 --> 00:13:49,840 together unless there are active sources 392 00:13:55,200 --> 00:13:51,850 of them and in this particular cases 393 00:13:57,960 --> 00:13:55,210 active sources are both life driven and 394 00:13:59,910 --> 00:13:57,970 so earth methane in the presence of 395 00:14:02,310 --> 00:13:59,920 oxygen is a bio signature but on Titan 396 00:14:04,470 --> 00:14:02,320 methane is just one of the main 397 00:14:07,200 --> 00:14:04,480 constituents or main trace gases of the 398 00:14:08,460 --> 00:14:07,210 atmosphere and so in titan case we don't 399 00:14:12,270 --> 00:14:08,470 think that a methane is actually 400 00:14:14,250 --> 00:14:12,280 indicative of life so what the virtual 401 00:14:16,380 --> 00:14:14,260 planetary laboratory does and what we 402 00:14:19,080 --> 00:14:16,390 have done is that we model planetary 403 00:14:21,600 --> 00:14:19,090 environments and their spectra so we 404 00:14:24,420 --> 00:14:21,610 have developed a suite of models of 405 00:14:26,070 --> 00:14:24,430 planetary environments including 1d 406 00:14:27,900 --> 00:14:26,080 spectral models of planets with known 407 00:14:30,270 --> 00:14:27,910 environments so that was the easiest 408 00:14:32,400 --> 00:14:30,280 thing to do so we have models of Venus 409 00:14:34,200 --> 00:14:32,410 Earth and Mars the beauty of a model 410 00:14:35,760 --> 00:14:34,210 even though we've got it observed all 411 00:14:37,410 --> 00:14:35,770 these planets as the model can run from 412 00:14:38,940 --> 00:14:37,420 the UV to the fire infrared with no 413 00:14:41,760 --> 00:14:38,950 dropouts due to the fact that we haven't 414 00:14:44,430 --> 00:14:41,770 got the data sources there so what we do 415 00:14:46,230 --> 00:14:44,440 is we can generate the model calibrate 416 00:14:48,120 --> 00:14:46,240 it validated against regions of the 417 00:14:49,560 --> 00:14:48,130 spectrum we have observed and then use 418 00:14:50,940 --> 00:14:49,570 physics and chemistry to predict what 419 00:14:53,820 --> 00:14:50,950 the rest of the spectrum will look like 420 00:14:56,580 --> 00:14:53,830 throughout the entire range we also have 421 00:14:57,810 --> 00:14:56,590 3d spectral models of planets in our own 422 00:15:00,300 --> 00:14:57,820 solar system namely 423 00:15:02,280 --> 00:15:00,310 Earth and Mars so these are models that 424 00:15:04,140 --> 00:15:02,290 where we input the atmospheric 425 00:15:07,710 --> 00:15:04,150 parameters of Earth and Mars and 426 00:15:09,330 --> 00:15:07,720 generate spectra for all the positions 427 00:15:10,890 --> 00:15:09,340 for a whole suite of positions on the 428 00:15:12,690 --> 00:15:10,900 planet so this three dimensional 429 00:15:15,480 --> 00:15:12,700 spectral model can be played around with 430 00:15:17,370 --> 00:15:15,490 and it was specifically designed to try 431 00:15:19,350 --> 00:15:17,380 and understand how detectable vegetation 432 00:15:20,820 --> 00:15:19,360 might be in the disk average but it can 433 00:15:22,350 --> 00:15:20,830 also be used to analyze things like 434 00:15:24,900 --> 00:15:22,360 earthshine data which is the disk 435 00:15:28,110 --> 00:15:24,910 average radiation that is reflected from 436 00:15:29,610 --> 00:15:28,120 the moon of the earth but we can also do 437 00:15:32,460 --> 00:15:29,620 fun things with the Mars model we've 438 00:15:34,920 --> 00:15:32,470 covered Mars sick consecutively with ice 439 00:15:36,570 --> 00:15:34,930 we had the polar ice cap work its way 440 00:15:38,070 --> 00:15:36,580 right down the planet and had a look at 441 00:15:42,060 --> 00:15:38,080 how the mass spectrum would evolve with 442 00:15:43,590 --> 00:15:42,070 time with that change in the co2 wife 443 00:15:45,180 --> 00:15:43,600 and interestingly you can in fact see 444 00:15:47,330 --> 00:15:45,190 the signature of co2 ice in the disk 445 00:15:50,280 --> 00:15:47,340 average even for the current ice caps 446 00:15:51,570 --> 00:15:50,290 but when when the ice comes down you 447 00:15:54,780 --> 00:15:51,580 definitely get a much stronger signature 448 00:15:56,940 --> 00:15:54,790 for co2 ice other things we've done that 449 00:15:59,340 --> 00:15:56,950 our main things that we like to work on 450 00:16:01,860 --> 00:15:59,350 our a 1d couple climate chemical models 451 00:16:03,240 --> 00:16:01,870 of plausible extrasolar environments so 452 00:16:05,430 --> 00:16:03,250 these are models that are based on 453 00:16:07,470 --> 00:16:05,440 models of planets in our own solar 454 00:16:10,140 --> 00:16:07,480 system but that are made sufficiently 455 00:16:12,300 --> 00:16:10,150 general that we can in fact model other 456 00:16:14,190 --> 00:16:12,310 types of environments and the things I'm 457 00:16:16,350 --> 00:16:14,200 going to talk about here are our early 458 00:16:19,860 --> 00:16:16,360 earth like environments and also 459 00:16:22,140 --> 00:16:19,870 earth-like planets around other stars so 460 00:16:24,390 --> 00:16:22,150 here are models of terrestrial planets 461 00:16:26,100 --> 00:16:24,400 in the visible and we're just going to 462 00:16:28,140 --> 00:16:26,110 run through these so that you'll learn 463 00:16:29,670 --> 00:16:28,150 in and be able to recognize some of the 464 00:16:31,860 --> 00:16:29,680 major features of the spectra I'm going 465 00:16:36,090 --> 00:16:31,870 to talk about in subsequent mr. the 466 00:16:38,910 --> 00:16:36,100 truck so Venus Earth and Mars these two 467 00:16:41,010 --> 00:16:38,920 planets Venus Venus and Mars actually 468 00:16:43,070 --> 00:16:41,020 are dominated by carbon dioxide 469 00:16:45,750 --> 00:16:43,080 absorption especially from the 470 00:16:47,400 --> 00:16:45,760 near-infrared outwards and that it might 471 00:16:48,720 --> 00:16:47,410 be difficult to tell but these are in 472 00:16:50,700 --> 00:16:48,730 fact the same features here at 473 00:16:52,620 --> 00:16:50,710 carbondale clay so that's what you see 474 00:16:56,100 --> 00:16:52,630 dominating the spectrum of these two 475 00:16:59,190 --> 00:16:56,110 planets for the Upper earth though is 476 00:17:01,710 --> 00:16:59,200 extremely different and it is dominated 477 00:17:04,890 --> 00:17:01,720 by water vapor throughout and then by 478 00:17:06,840 --> 00:17:04,900 oxygen the oxygen a band which is which 479 00:17:08,050 --> 00:17:06,850 is there and the other thing that you 480 00:17:09,970 --> 00:17:08,060 can see on this planet 481 00:17:12,280 --> 00:17:09,980 is that in a relatively cloud-free earth 482 00:17:14,770 --> 00:17:12,290 you do have a tune up to the blue word 483 00:17:16,480 --> 00:17:14,780 end of the spectrum of earth that is due 484 00:17:19,300 --> 00:17:16,490 to Rayleigh scattering from molecules in 485 00:17:21,580 --> 00:17:19,310 our atmosphere and in the case of Venus 486 00:17:22,930 --> 00:17:21,590 even though this is often used as an 487 00:17:25,120 --> 00:17:22,940 indicator of atmospheric pressure by the 488 00:17:26,610 --> 00:17:25,130 way but for Venus even though its 489 00:17:28,990 --> 00:17:26,620 atmospheric pressure is higher overall 490 00:17:31,810 --> 00:17:29,000 again we're only sampling the atmosphere 491 00:17:34,840 --> 00:17:31,820 above the cloud deck which is much much 492 00:17:36,550 --> 00:17:34,850 has much less mathematics fear and I 493 00:17:38,350 --> 00:17:36,560 think close to 30 millibars or something 494 00:17:40,720 --> 00:17:38,360 like that and so you really don't see as 495 00:17:41,980 --> 00:17:40,730 much of an upward turn here plus Venus 496 00:17:44,500 --> 00:17:41,990 also has this thing called the unknown 497 00:17:45,970 --> 00:17:44,510 UV absorber which is a UV absorber which 498 00:17:48,130 --> 00:17:45,980 we don't know what it is hence it's 499 00:17:49,960 --> 00:17:48,140 called the others over and the unknown 500 00:17:52,570 --> 00:17:49,970 UV absorber does in fact tend to absorb 501 00:17:54,610 --> 00:17:52,580 that blue Orenda way so it masks 502 00:17:56,380 --> 00:17:54,620 anywhere Lee's getting more thing on 503 00:17:58,480 --> 00:17:56,390 Mars the situation is even worse in his 504 00:18:00,370 --> 00:17:58,490 innocence Mars has strong absorption 505 00:18:02,260 --> 00:18:00,380 from iron oxide on the surface of the 506 00:18:04,600 --> 00:18:02,270 planet and its weak Rayleigh scattering 507 00:18:06,820 --> 00:18:04,610 atmosphere is no match for for that 508 00:18:08,020 --> 00:18:06,830 absorption features so when Mars let me 509 00:18:10,120 --> 00:18:08,030 have it looks like a negative really 510 00:18:12,250 --> 00:18:10,130 effect but that's of course not possible 511 00:18:14,860 --> 00:18:12,260 and what you're seeing as in fact I 512 00:18:17,080 --> 00:18:14,870 off-site absorption on the surface so if 513 00:18:18,730 --> 00:18:17,090 we go to the mid-infrared so this is 514 00:18:21,940 --> 00:18:18,740 just a different wavelength regime same 515 00:18:23,620 --> 00:18:21,950 plants you can see this thing I was 516 00:18:25,510 --> 00:18:23,630 talking about the carbon dioxide feature 517 00:18:27,850 --> 00:18:25,520 which is extremely strong on all of them 518 00:18:30,100 --> 00:18:27,860 and that's kind of going to be the 519 00:18:31,630 --> 00:18:30,110 easiest thing for a telescope to detect 520 00:18:32,830 --> 00:18:31,640 not that any of this is easy but a 521 00:18:35,380 --> 00:18:32,840 relatively if you think them in to 522 00:18:37,510 --> 00:18:35,390 detect is this this broad carbon dioxide 523 00:18:39,550 --> 00:18:37,520 band to say yes I have a planet with an 524 00:18:40,990 --> 00:18:39,560 atmosphere it's probably terrestrial so 525 00:18:43,240 --> 00:18:41,000 one of the things we'll look for you 526 00:18:45,040 --> 00:18:43,250 also have water vapor in all of these 527 00:18:46,480 --> 00:18:45,050 atmosphere so in Venus and Mars very 528 00:18:48,850 --> 00:18:46,490 small amounts and you can see that the 529 00:18:51,490 --> 00:18:48,860 the h2o water vapor continuum down here 530 00:18:54,460 --> 00:18:51,500 is far more depressed than these other 531 00:18:56,530 --> 00:18:54,470 two but what you also see is that the 532 00:18:58,840 --> 00:18:56,540 again the earth spectrum is the most 533 00:19:00,490 --> 00:18:58,850 complicated of all of them and it is 534 00:19:02,170 --> 00:19:00,500 reviewthe wavelength regime down here 535 00:19:04,390 --> 00:19:02,180 was sensitive to a number of different 536 00:19:06,640 --> 00:19:04,400 metabolites so things out things that 537 00:19:09,310 --> 00:19:06,650 life outputs like nitrous oxide and 538 00:19:11,620 --> 00:19:09,320 methane and ozone which is used as a 539 00:19:14,030 --> 00:19:11,630 proxy for oxygen so you can see the 540 00:19:16,070 --> 00:19:14,040 strong ozone band here 541 00:19:18,230 --> 00:19:16,080 maybe this is the wavelength regime here 542 00:19:20,330 --> 00:19:18,240 where marcio to ice absorbs and that's 543 00:19:21,950 --> 00:19:20,340 where we would look for say a planet 544 00:19:24,020 --> 00:19:21,960 that he may be undergone have this very 545 00:19:25,670 --> 00:19:24,030 collapse and frozen its atmosphere out 546 00:19:29,810 --> 00:19:25,680 of the surface you might look for that 547 00:19:32,960 --> 00:19:29,820 fun on in there so I've been showing all 548 00:19:35,270 --> 00:19:32,970 these lovely spectra zero noise and you 549 00:19:36,620 --> 00:19:35,280 know lovely special resolution but an 550 00:19:38,270 --> 00:19:36,630 actual fact when we look for planets 551 00:19:41,810 --> 00:19:38,280 around other stars we will be photon 552 00:19:44,000 --> 00:19:41,820 starved as I said and so the the 553 00:19:45,680 --> 00:19:44,010 resolution of our spectrographs is not 554 00:19:48,110 --> 00:19:45,690 going to be very high so because we need 555 00:19:49,640 --> 00:19:48,120 to bend as many photons as possible into 556 00:19:51,260 --> 00:19:49,650 the individual business to get enough 557 00:19:53,450 --> 00:19:51,270 signal to noise to be able to detect a 558 00:19:56,750 --> 00:19:53,460 feature so what I've plotted here this 559 00:19:58,370 --> 00:19:56,760 is still zero noise but it shows the 560 00:20:00,760 --> 00:19:58,380 type of special resolution we might 561 00:20:03,290 --> 00:20:00,770 expect with an instrument called T PFC 562 00:20:04,610 --> 00:20:03,300 which is going to be a large telescope 563 00:20:09,080 --> 00:20:04,620 that is sensitive to light in the 564 00:20:10,970 --> 00:20:09,090 optical type CCD type sensitivities and 565 00:20:12,910 --> 00:20:10,980 from there you can see that even from 566 00:20:16,010 --> 00:20:12,920 Venus several of these features 567 00:20:17,630 --> 00:20:16,020 including a strong co2 bands I become a 568 00:20:21,320 --> 00:20:17,640 little bit washed out but still that's 569 00:20:23,060 --> 00:20:21,330 the 1 point 1 05 micron co2 man that's 570 00:20:24,860 --> 00:20:23,070 still probably going to be detectable a 571 00:20:26,990 --> 00:20:24,870 treasonable signal to noise there's the 572 00:20:29,480 --> 00:20:27,000 earth's oxygen land but one thing I like 573 00:20:30,920 --> 00:20:29,490 to show in this plot is that it's very 574 00:20:32,120 --> 00:20:30,930 important to have a wide wavelength 575 00:20:34,550 --> 00:20:32,130 range when you're trying to characterize 576 00:20:37,880 --> 00:20:34,560 these things because at this wavelength 577 00:20:40,130 --> 00:20:37,890 point 7 25 depending on your planet the 578 00:20:42,530 --> 00:20:40,140 dip you see is either carbon dioxide 579 00:20:44,810 --> 00:20:42,540 water vapor or methane at these 580 00:20:46,700 --> 00:20:44,820 resolutions okay so it's very important 581 00:20:48,770 --> 00:20:46,710 to have more wavelength range around 582 00:20:50,600 --> 00:20:48,780 this area and this would be the area we 583 00:20:52,400 --> 00:20:50,610 would choose to try and get B be able to 584 00:20:54,890 --> 00:20:52,410 do bad you will need more wavelengths 585 00:20:57,140 --> 00:20:54,900 around that area to to capture you know 586 00:20:59,090 --> 00:20:57,150 second and third absorptions are the 587 00:21:02,270 --> 00:20:59,100 same species to confirm the detection of 588 00:21:04,340 --> 00:21:02,280 the thing you think you're seeing okay 589 00:21:06,080 --> 00:21:04,350 so now we'll move on to some of the the 590 00:21:08,180 --> 00:21:06,090 vpl modeling how that we've been doing 591 00:21:10,970 --> 00:21:08,190 this is work that's been led by our 592 00:21:13,610 --> 00:21:10,980 postdoc and second Isidoro who has just 593 00:21:15,830 --> 00:21:13,620 recently left us for a university job at 594 00:21:18,800 --> 00:21:15,840 you nom she says her dream job so we're 595 00:21:20,230 --> 00:21:18,810 very happy for her there and I just 596 00:21:22,060 --> 00:21:20,240 listed the names of 597 00:21:24,520 --> 00:21:22,070 real people who were intimately involved 598 00:21:26,049 --> 00:21:24,530 in doing this work and just showed their 599 00:21:28,870 --> 00:21:26,059 expertise to show you that this is a 600 00:21:30,660 --> 00:21:28,880 truly interdisciplinary effort we have 601 00:21:33,010 --> 00:21:30,670 you know still a radiation experts 602 00:21:34,870 --> 00:21:33,020 dealing with biology experts and then 603 00:21:38,830 --> 00:21:34,880 the climate chemistry and planetary 604 00:21:42,610 --> 00:21:38,840 modelers as well so what we've done here 605 00:21:45,040 --> 00:21:42,620 is taken one day photochemical models 606 00:21:46,240 --> 00:21:45,050 and radiative convective models and have 607 00:21:48,120 --> 00:21:46,250 them coupled together so that they 608 00:21:51,070 --> 00:21:48,130 interact with each other to produce 609 00:21:53,560 --> 00:21:51,080 self-consistent environments and what I 610 00:21:55,510 --> 00:21:53,570 mean by that is that when the radiation 611 00:21:58,330 --> 00:21:55,520 from the star comes into the atmosphere 612 00:22:00,549 --> 00:21:58,340 and heats it up due to absorption from 613 00:22:02,799 --> 00:22:00,559 species in the atmosphere we run the 614 00:22:04,540 --> 00:22:02,809 models so that that heating then affects 615 00:22:06,220 --> 00:22:04,550 the chemistry and the resultant 616 00:22:07,690 --> 00:22:06,230 chemistry that affects the heating so 617 00:22:10,210 --> 00:22:07,700 the whole thing is coupled till it 618 00:22:11,680 --> 00:22:10,220 becomes a self-consistent state so I 619 00:22:13,210 --> 00:22:11,690 haven't just you know throw an oxygen up 620 00:22:14,710 --> 00:22:13,220 into this ozone up into the atmosphere 621 00:22:15,790 --> 00:22:14,720 and expected that but nothing would 622 00:22:17,560 --> 00:22:15,800 change in the temperature structure 623 00:22:19,180 --> 00:22:17,570 because I know ozone will absorb UV and 624 00:22:20,440 --> 00:22:19,190 it will heat it up so that's the 625 00:22:22,360 --> 00:22:20,450 self-consistent climate chemical 626 00:22:24,430 --> 00:22:22,370 modeling that we do once we've actually 627 00:22:26,169 --> 00:22:24,440 gotten an environmental state using this 628 00:22:30,010 --> 00:22:26,179 we run it through the smart radiative 629 00:22:32,620 --> 00:22:30,020 transfer model and that then helps us to 630 00:22:34,419 --> 00:22:32,630 generate is simple spectra of what the 631 00:22:36,760 --> 00:22:34,429 environment would look like so we can 632 00:22:39,480 --> 00:22:36,770 see what a telescope would see if it was 633 00:22:42,910 --> 00:22:39,490 looking at this particular environment 634 00:22:44,500 --> 00:22:42,920 so the first step in doing this modeling 635 00:22:46,150 --> 00:22:44,510 because it's earth around other stars is 636 00:22:48,640 --> 00:22:46,160 to make sure we have really good input 637 00:22:50,140 --> 00:22:48,650 stellar spectra and so instead of 638 00:22:51,640 --> 00:22:50,150 approximating these as a black body 639 00:22:53,080 --> 00:22:51,650 which would cause Martin CO and our 640 00:22:56,169 --> 00:22:53,090 collaborator to collapse with a heart 641 00:22:58,120 --> 00:22:56,179 attack we have used realistic stellar 642 00:23:00,640 --> 00:22:58,130 spectra with from real stars with names 643 00:23:03,520 --> 00:23:00,650 and gathered as much data as we possibly 644 00:23:04,810 --> 00:23:03,530 can and Martin has worked with us to to 645 00:23:06,310 --> 00:23:04,820 so all of this together along with 646 00:23:08,830 --> 00:23:06,320 next-gen models and a bunch of other 647 00:23:10,419 --> 00:23:08,840 things to get the best possible full 648 00:23:12,850 --> 00:23:10,429 wavelength range spectrum of the star we 649 00:23:14,799 --> 00:23:12,860 possibly can and in this particular case 650 00:23:16,630 --> 00:23:14,809 having accurate representation of the UV 651 00:23:18,760 --> 00:23:16,640 is really important because the UV is 652 00:23:20,770 --> 00:23:18,770 what drives the photochemistry and I 653 00:23:22,980 --> 00:23:20,780 noticed we choose TPF target stars based 654 00:23:25,210 --> 00:23:22,990 on their their optical classifications 655 00:23:26,500 --> 00:23:25,220 but it turns out that the you fee is 656 00:23:28,480 --> 00:23:26,510 actually going to be in the main 657 00:23:29,880 --> 00:23:28,490 indicator of what you're going to see 658 00:23:32,160 --> 00:23:29,890 and what the planet is going to be 659 00:23:33,540 --> 00:23:32,170 and that may not be the same even for 660 00:23:36,300 --> 00:23:33,550 something in the same spectral class 661 00:23:38,490 --> 00:23:36,310 determined in the visible so the Stars 662 00:23:41,130 --> 00:23:38,500 we used for this where the Sun an 663 00:23:44,100 --> 00:23:41,140 obvious one to start with we use an f2 664 00:23:45,600 --> 00:23:44,110 star K 2 star K 2 dwarfs and then we 665 00:23:47,640 --> 00:23:45,610 used a dealio which is probably one of 666 00:23:49,380 --> 00:23:47,650 the most active M stars known so that 667 00:23:52,170 --> 00:23:49,390 was an extreme end of it and then we 668 00:23:54,450 --> 00:23:52,180 also used a model of a similar spectral 669 00:23:55,920 --> 00:23:54,460 type but that had no activity it 670 00:23:57,090 --> 00:23:55,930 actually doesn't have a chromis fear and 671 00:23:59,640 --> 00:23:57,100 yes I know this is completely 672 00:24:01,950 --> 00:23:59,650 unrealistic however it serves as a lower 673 00:24:04,890 --> 00:24:01,960 bound on the type of UV activity we're 674 00:24:06,210 --> 00:24:04,900 going to see from these stars and so 675 00:24:08,670 --> 00:24:06,220 there are the stellar spectra we used 676 00:24:09,960 --> 00:24:08,680 and there you be activity and it's 677 00:24:15,300 --> 00:24:09,970 interesting too but the more active 678 00:24:17,070 --> 00:24:15,310 stars like 80 Leo for example where she 679 00:24:19,440 --> 00:24:17,080 do get a lot of UV that's almost 680 00:24:24,120 --> 00:24:19,450 comparable with the Sun at the shorter 681 00:24:25,770 --> 00:24:24,130 wavelengths so one thing we looked at as 682 00:24:27,930 --> 00:24:25,780 far as habitability is concerned as is 683 00:24:30,660 --> 00:24:27,940 we put these planets around stars a 684 00:24:32,880 --> 00:24:30,670 different spectral type and around their 685 00:24:35,040 --> 00:24:32,890 their temperature structures and looked 686 00:24:37,200 --> 00:24:35,050 at how for example things like the ozone 687 00:24:39,090 --> 00:24:37,210 would adjust within the atmosphere as 688 00:24:40,860 --> 00:24:39,100 are these different colors even though 689 00:24:42,450 --> 00:24:40,870 they're labeled by star named are 690 00:24:44,820 --> 00:24:42,460 actually the planets around that star 691 00:24:46,830 --> 00:24:44,830 and each planet was put around its star 692 00:24:49,710 --> 00:24:46,840 in the habitable zone so we gave it that 693 00:24:52,260 --> 00:24:49,720 much of a chance and what you're seeing 694 00:24:55,170 --> 00:24:52,270 here is the formation an extremely hot 695 00:24:56,880 --> 00:24:55,180 stratosphere in the f star because this 696 00:24:59,700 --> 00:24:56,890 is earthed remember it has oxygen in it 697 00:25:02,160 --> 00:24:59,710 so we created ozone very very strong 698 00:25:04,800 --> 00:25:02,170 ozone meijer in this particular case in 699 00:25:06,210 --> 00:25:04,810 the nstar case we didn't create as much 700 00:25:08,790 --> 00:25:06,220 of an ozone layer so you don't see as 701 00:25:11,790 --> 00:25:08,800 much stress for heating there but what 702 00:25:13,590 --> 00:25:11,800 we also did was then look at how much of 703 00:25:15,750 --> 00:25:13,600 the UV radiation actually came through 704 00:25:17,310 --> 00:25:15,760 the planetary atmosphere and hit the 705 00:25:19,410 --> 00:25:17,320 surface of the planet and what that 706 00:25:22,080 --> 00:25:19,420 would do in the way of DNA damage for 707 00:25:23,880 --> 00:25:22,090 these these various types of planets so 708 00:25:26,220 --> 00:25:23,890 it turns out that the interaction of the 709 00:25:28,830 --> 00:25:26,230 UV radiation from the star with the 710 00:25:30,600 --> 00:25:28,840 oxygen in our atmosphere reduced ozone 711 00:25:33,510 --> 00:25:30,610 layers that just seemed to almost full a 712 00:25:36,190 --> 00:25:33,520 Goldilocks principle in the center 713 00:25:38,170 --> 00:25:36,200 even for the F star with a lot of UV 714 00:25:40,060 --> 00:25:38,180 radiation it formed a super ozone layer 715 00:25:41,740 --> 00:25:40,070 and was able to block most of the 716 00:25:43,420 --> 00:25:41,750 dangerous UV radiation computing the 717 00:25:45,940 --> 00:25:43,430 surface of the planet so the actual 718 00:25:48,790 --> 00:25:45,950 percentage DNA damage a relative DNA 719 00:25:50,770 --> 00:25:48,800 damage relative to the earth was in fact 720 00:25:53,470 --> 00:25:50,780 less slightly less in this particular 721 00:25:56,410 --> 00:25:53,480 case and also for the case even though 722 00:25:58,300 --> 00:25:56,420 it didn't produce as as thicken ozone 723 00:26:00,280 --> 00:25:58,310 layer as the earth it still managed to 724 00:26:02,830 --> 00:26:00,290 feel the surface of the planet pretty 725 00:26:04,510 --> 00:26:02,840 well so we discovered that you know 726 00:26:07,480 --> 00:26:04,520 earth is actually pretty robust to 727 00:26:09,700 --> 00:26:07,490 changes in the UV flux inspection with 728 00:26:11,380 --> 00:26:09,710 the parent star so there's this reason 729 00:26:13,990 --> 00:26:11,390 to hope that a box genic photosynthesis 730 00:26:16,060 --> 00:26:14,000 develops and you do have the oxygen no 731 00:26:18,760 --> 00:26:16,070 matter what spectral type it's your star 732 00:26:20,950 --> 00:26:18,770 is you can still have an ozone shield so 733 00:26:23,350 --> 00:26:20,960 we we then calculated we then cut the 734 00:26:24,460 --> 00:26:23,360 ozone by factors of 10 and calculated at 735 00:26:26,140 --> 00:26:24,470 which point we really wouldn't want to 736 00:26:27,610 --> 00:26:26,150 go out and go sunbathing and we 737 00:26:30,340 --> 00:26:27,620 discovered that the critical threshold 738 00:26:32,200 --> 00:26:30,350 for oxygen ride a UV planetary shield is 739 00:26:34,390 --> 00:26:32,210 probably about 1% of the current level 740 00:26:36,220 --> 00:26:34,400 we have in our atmosphere so even at one 741 00:26:38,050 --> 00:26:36,230 percent of the current level that's 742 00:26:41,380 --> 00:26:38,060 still moderately reasonable on the 743 00:26:43,240 --> 00:26:41,390 surface of the planet for UV flux we 744 00:26:44,890 --> 00:26:43,250 also looked at what happened to other 745 00:26:46,330 --> 00:26:44,900 bio signatures in the atmosphere when 746 00:26:49,270 --> 00:26:46,340 the planet went around a star of a 747 00:26:51,460 --> 00:26:49,280 different spectral type so we looked at 748 00:26:52,960 --> 00:26:51,470 three major biomarkers to you've 749 00:26:54,790 --> 00:26:52,970 probably heard of methane and nitrous 750 00:26:57,910 --> 00:26:54,800 oxide but the new one was methyl 751 00:27:00,610 --> 00:26:57,920 chloride which is in fact produced by 752 00:27:02,290 --> 00:27:00,620 biomass burning on our planet this also 753 00:27:04,350 --> 00:27:02,300 comes from the oceans and I think it's 754 00:27:06,670 --> 00:27:04,360 supposed to be part of algae or perhaps 755 00:27:08,530 --> 00:27:06,680 producing insulin but it's something 756 00:27:10,660 --> 00:27:08,540 that was in the climate chemical model 757 00:27:12,790 --> 00:27:10,670 which we had been taken out to model 758 00:27:14,110 --> 00:27:12,800 straight spectrally before and we just 759 00:27:15,970 --> 00:27:14,120 decided well what the heck you know even 760 00:27:17,380 --> 00:27:15,980 though it's not that detectable in the 761 00:27:18,760 --> 00:27:17,390 Earth's atmosphere who knows how 762 00:27:21,250 --> 00:27:18,770 detectable it might be on a planet 763 00:27:23,500 --> 00:27:21,260 around another star and so what we did 764 00:27:25,300 --> 00:27:23,510 what we're showing here is insert the 765 00:27:26,830 --> 00:27:25,310 mixing ratio of these different gases 766 00:27:28,330 --> 00:27:26,840 how much of these different gases are in 767 00:27:31,240 --> 00:27:28,340 the atmospheres of these planets and how 768 00:27:33,360 --> 00:27:31,250 they drop off with Alta tube and this 769 00:27:35,950 --> 00:27:33,370 drop off of course is probably due to UV 770 00:27:36,580 --> 00:27:35,960 fotosis and or chemical removal in the 771 00:27:39,519 --> 00:27:36,590 case 772 00:27:43,210 --> 00:27:39,529 in the upper atmosphere but what you see 773 00:27:45,010 --> 00:27:43,220 here is a very big dichotomy between you 774 00:27:48,669 --> 00:27:45,020 know the abundance of methane on stars 775 00:27:51,430 --> 00:27:48,679 around fgk on planets on FG k and then 776 00:27:53,560 --> 00:27:51,440 how much you get in the atmospheres of M 777 00:27:55,690 --> 00:27:53,570 star planners and in all cases these 778 00:27:57,460 --> 00:27:55,700 biomarkers tended to build up in the 779 00:28:00,010 --> 00:27:57,470 atmospheres of MCR planets because they 780 00:28:01,600 --> 00:28:00,020 had much longer lifetimes there so if 781 00:28:03,490 --> 00:28:01,610 you look at the lifetimes is certainly a 782 00:28:07,120 --> 00:28:03,500 transition when you go from the FD k 783 00:28:08,529 --> 00:28:07,130 through to the M stars dramatic 784 00:28:11,409 --> 00:28:08,539 increases in the lifetimes of some 785 00:28:13,230 --> 00:28:11,419 things but interestingly the methane and 786 00:28:16,710 --> 00:28:13,240 methyl chloride er actually scrubbed out 787 00:28:20,049 --> 00:28:16,720 by o-h production in the no sig let D 788 00:28:23,440 --> 00:28:20,059 which requires certain UV radiation to 789 00:28:25,480 --> 00:28:23,450 initiate that reaction and so they in 790 00:28:27,100 --> 00:28:25,490 fact have longer lifetimes relative to 791 00:28:29,620 --> 00:28:27,110 something like nitrous oxide which is 792 00:28:31,720 --> 00:28:29,630 just simply fertilized in the atmosphere 793 00:28:34,330 --> 00:28:31,730 so we found that in fact nitrous oxide 794 00:28:36,039 --> 00:28:34,340 didn't build up your quite as rapidly as 795 00:28:38,440 --> 00:28:36,049 we would have liked practic to between 796 00:28:41,470 --> 00:28:38,450 here and here instead of new a factor of 797 00:28:43,779 --> 00:28:41,480 a thousand for the methyl chloride and 798 00:28:46,570 --> 00:28:43,789 methane build-up so certainly for M star 799 00:28:49,060 --> 00:28:46,580 planets around planets around M stars 800 00:28:50,919 --> 00:28:49,070 you would tend to get we believe a 801 00:28:54,430 --> 00:28:50,929 buildup of these methylated compounds in 802 00:28:56,049 --> 00:28:54,440 the atmosphere so what we did then was 803 00:28:58,360 --> 00:28:56,059 model what the spectra of these planets 804 00:29:01,269 --> 00:28:58,370 would look like and the black line here 805 00:29:03,700 --> 00:29:01,279 is earth just for reference and the red 806 00:29:05,789 --> 00:29:03,710 line is the planet around a dealio so 807 00:29:08,880 --> 00:29:05,799 this is the active flaring M star and 808 00:29:11,049 --> 00:29:08,890 this is what we saw in the final 809 00:29:12,700 --> 00:29:11,059 atmosphere what we saw was greatly 810 00:29:14,560 --> 00:29:12,710 enhanced methane absorption which as 811 00:29:17,680 --> 00:29:14,570 I've just described in my expect because 812 00:29:19,690 --> 00:29:17,690 the mech own lifetime went up and we see 813 00:29:21,970 --> 00:29:19,700 because the game around an M star we 814 00:29:23,830 --> 00:29:21,980 don't have too much ozone in the upper 815 00:29:25,600 --> 00:29:23,840 atmosphere being produced so you're not 816 00:29:28,359 --> 00:29:25,610 seeing a hot stratosphere here like you 817 00:29:31,249 --> 00:29:28,369 would on the earth so that's also good 818 00:29:33,919 --> 00:29:31,259 but we also saw nitrous oxide detection 819 00:29:36,109 --> 00:29:33,929 beard this is methyl chloride here and 820 00:29:37,519 --> 00:29:36,119 here and a little bit over here but we 821 00:29:39,109 --> 00:29:37,529 were able to see that in the spectrum 822 00:29:40,369 --> 00:29:39,119 now she methyl chloride is very 823 00:29:42,649 --> 00:29:40,379 interesting when I first plotted its 824 00:29:44,239 --> 00:29:42,659 absorption spectrum it actually has a 825 00:29:47,840 --> 00:29:44,249 very strong absorption right here in the 826 00:29:49,279 --> 00:29:47,850 ozone as well same wavelength so it 827 00:29:52,159 --> 00:29:49,289 actually mimics a lot of our bio 828 00:29:57,940 --> 00:29:52,169 signatures in one molecule so it can be 829 00:30:00,379 --> 00:29:57,950 hard to pull out from from the others so 830 00:30:02,269 --> 00:30:00,389 what we also looked at is of course the 831 00:30:05,810 --> 00:30:02,279 FG k planetary spectra and how they 832 00:30:07,609 --> 00:30:05,820 change essentially what we were seeing 833 00:30:09,259 --> 00:30:07,619 here was again the change in the 834 00:30:10,820 --> 00:30:09,269 strength of the ozone layer and heating 835 00:30:12,859 --> 00:30:10,830 of the stratosphere was was present in 836 00:30:15,229 --> 00:30:12,869 the carbon dioxide and again you saw 837 00:30:17,450 --> 00:30:15,239 that in the euro zone itself the direct 838 00:30:18,529 --> 00:30:17,460 measure over in the visible the only 839 00:30:20,619 --> 00:30:18,539 thing that really changed in the 840 00:30:23,629 --> 00:30:20,629 spectrum was the ozone ship we bands 841 00:30:25,249 --> 00:30:23,639 between point five and point seven they 842 00:30:28,970 --> 00:30:25,259 changed his strength again depending on 843 00:30:30,499 --> 00:30:28,980 the ozone level in the atmosphere and 844 00:30:32,629 --> 00:30:30,509 here's just a blow-up of that showing 845 00:30:35,659 --> 00:30:32,639 exactly what was going on this was very 846 00:30:39,649 --> 00:30:35,669 intriguing it turned out that the the 847 00:30:41,330 --> 00:30:39,659 ozone absorption for the G&K stars was 848 00:30:42,919 --> 00:30:41,340 almost the same level of detectability 849 00:30:45,379 --> 00:30:42,929 even though the case Tara had far less 850 00:30:47,659 --> 00:30:45,389 ozone in its atmosphere and this week 851 00:30:49,849 --> 00:30:47,669 was because the cupboard had far less 852 00:30:52,460 --> 00:30:49,859 ozone and strong sphere wasn't as hot 853 00:30:53,899 --> 00:30:52,470 and so the coolest stratosphere relative 854 00:30:55,580 --> 00:30:53,909 to the surface of the planet meant that 855 00:30:57,470 --> 00:30:55,590 we got more absorption more bang for the 856 00:30:59,450 --> 00:30:57,480 buck an absorption for a smaller amount 857 00:31:02,419 --> 00:30:59,460 of material because of that temperature 858 00:31:04,220 --> 00:31:02,429 difference conversely for the estar we 859 00:31:06,349 --> 00:31:04,230 had loads of ozone in the atmosphere but 860 00:31:07,580 --> 00:31:06,359 that heated up the stratosphere and so 861 00:31:09,109 --> 00:31:07,590 we didn't get as much of a temperature 862 00:31:11,690 --> 00:31:09,119 differential with the surface and so 863 00:31:13,999 --> 00:31:11,700 that absorption was in fact less so so 864 00:31:15,619 --> 00:31:14,009 the point I want to make here is greater 865 00:31:16,729 --> 00:31:15,629 than any of you know the strength of 866 00:31:18,289 --> 00:31:16,739 your absorption feature and how 867 00:31:20,479 --> 00:31:18,299 detectable it would be to a telescope 868 00:31:22,639 --> 00:31:20,489 depends not only on the amount of 869 00:31:24,259 --> 00:31:22,649 material you have but on the temperature 870 00:31:26,029 --> 00:31:24,269 structure that material is embedded in 871 00:31:27,619 --> 00:31:26,039 that's really important when we're 872 00:31:30,169 --> 00:31:27,629 trying to pull out the characteristics 873 00:31:32,450 --> 00:31:30,179 of these planets and then the methane we 874 00:31:33,950 --> 00:31:32,460 saw predictably on the later type star 875 00:31:35,840 --> 00:31:33,960 the case they are not as much methane 876 00:31:37,330 --> 00:31:35,850 described destruction and so a stronger 877 00:31:40,490 --> 00:31:37,340 mapping feature 878 00:31:42,110 --> 00:31:40,500 so here and this is a bit much to get 879 00:31:45,770 --> 00:31:42,120 into but i'll try and we have the 880 00:31:48,680 --> 00:31:45,780 salient points that this was what 881 00:31:50,299 --> 00:31:48,690 happens when we took the oxygen in the 882 00:31:51,590 --> 00:31:50,309 atmosphere from present atmospheric 883 00:31:53,299 --> 00:31:51,600 level which is what we currently have on 884 00:31:55,400 --> 00:31:53,309 the earth and brought it down by factors 885 00:31:57,650 --> 00:31:55,410 of 10 successively we then looked at the 886 00:32:00,110 --> 00:31:57,660 detectability of oxygen and ozone when 887 00:32:02,900 --> 00:32:00,120 we did that on the planet so for planets 888 00:32:04,490 --> 00:32:02,910 around F G and K stars with different 889 00:32:07,280 --> 00:32:04,500 oxygen abundances and their atmospheres 890 00:32:10,370 --> 00:32:07,290 what we saw again was the GPS nails are 891 00:32:12,590 --> 00:32:10,380 pretty similar the f star for the ozone 892 00:32:14,780 --> 00:32:12,600 was pathological because of this release 893 00:32:16,580 --> 00:32:14,790 super hot stratosphere and so what we 894 00:32:18,080 --> 00:32:16,590 found there was in fact if you had the 895 00:32:20,270 --> 00:32:18,090 current level of oxygen in our 896 00:32:22,430 --> 00:32:20,280 atmosphere the ozone was less detectable 897 00:32:24,260 --> 00:32:22,440 than if you had only one percent of the 898 00:32:25,700 --> 00:32:24,270 current oxygen in our atmosphere that 899 00:32:26,870 --> 00:32:25,710 was actually the sweet spot at one 900 00:32:29,360 --> 00:32:26,880 percent of the current level of oxygen 901 00:32:30,500 --> 00:32:29,370 and the UV of the f star that was the 902 00:32:33,500 --> 00:32:30,510 point in which we got the strongest 903 00:32:35,720 --> 00:32:33,510 detection of ozone swamis Legion after 904 00:32:37,340 --> 00:32:35,730 oxygen there look identical right across 905 00:32:38,960 --> 00:32:37,350 the board so the spectrum of the parent 906 00:32:43,310 --> 00:32:38,970 star didn't really change her ability to 907 00:32:45,860 --> 00:32:43,320 detect the oxygen at all and essentially 908 00:32:48,140 --> 00:32:45,870 we were sensitive down to about one part 909 00:32:49,970 --> 00:32:48,150 in 10 to the minus 3 here for these 910 00:32:52,130 --> 00:32:49,980 types being able to take something below 911 00:32:54,640 --> 00:32:52,140 that really very difficult to the state 912 00:32:56,960 --> 00:32:54,650 but down here probably only one part and 913 00:32:58,520 --> 00:32:56,970 10 to the minus 2 1 percent of the 914 00:33:00,919 --> 00:32:58,530 current oxygen level is going to be 915 00:33:03,890 --> 00:33:00,929 something we battle for and even that it 916 00:33:07,490 --> 00:33:03,900 would be quite hard to detect so for the 917 00:33:08,570 --> 00:33:07,500 active mstar planets we also looked at 918 00:33:12,230 --> 00:33:08,580 the difference in the spectrum between 919 00:33:14,330 --> 00:33:12,240 Earth which is the black line and a PPO 920 00:33:16,549 --> 00:33:14,340 which is the red line here this is the 921 00:33:18,080 --> 00:33:16,559 active n star the main difference we saw 922 00:33:21,830 --> 00:33:18,090 was in the methane the methane buildup 923 00:33:23,750 --> 00:33:21,840 in the atmosphere around the M star and 924 00:33:25,430 --> 00:33:23,760 there for some reason I have this methyl 925 00:33:27,080 --> 00:33:25,440 chloride slide out of sequence apologize 926 00:33:30,440 --> 00:33:27,090 for that so again the one you've already 927 00:33:32,600 --> 00:33:30,450 just seen of the features are in the mid 928 00:33:33,120 --> 00:33:32,610 infrared with that methyl chloride in 929 00:33:36,570 --> 00:33:33,130 here 930 00:33:39,810 --> 00:33:36,580 very strong feature from methyl chloride 931 00:33:41,010 --> 00:33:39,820 right there and so here is a plot 932 00:33:43,860 --> 00:33:41,020 showing you where methyl chloride 933 00:33:45,660 --> 00:33:43,870 absorbs what I've done is we modeled a 934 00:33:46,590 --> 00:33:45,670 dealio without the methyl chloride so 935 00:33:48,360 --> 00:33:46,600 that's what it's affection would have 936 00:33:50,250 --> 00:33:48,370 looked like a blue one and then we 937 00:33:52,170 --> 00:33:50,260 modeled it Oh with the methyl chloride 938 00:33:55,470 --> 00:33:52,180 that's the red one and you can see the 939 00:33:57,180 --> 00:33:55,480 regions in which it absorbs so that's a 940 00:33:58,410 --> 00:33:57,190 potential new biomarker to look for 941 00:34:02,370 --> 00:33:58,420 which have not previously been 942 00:34:04,110 --> 00:34:02,380 considered and then finally again back 943 00:34:05,700 --> 00:34:04,120 to reality these are the type of 944 00:34:08,129 --> 00:34:05,710 resolutions we might expect from the 945 00:34:10,260 --> 00:34:08,139 first generation of TPF I which is the 946 00:34:12,000 --> 00:34:10,270 interferometer in the mid infrared so 947 00:34:13,020 --> 00:34:12,010 resolution about 20 across that 948 00:34:15,540 --> 00:34:13,030 wavelength range I've just been showing 949 00:34:17,340 --> 00:34:15,550 you nonetheless it's tough but 950 00:34:19,169 --> 00:34:17,350 nonetheless we still might be able to 951 00:34:22,050 --> 00:34:19,179 pick up the ozone even if anyone picks 952 00:34:24,149 --> 00:34:22,060 up here um and we can also look if we 953 00:34:25,710 --> 00:34:24,159 get good enough signal to noise to look 954 00:34:28,560 --> 00:34:25,720 for that central peak that would 955 00:34:31,290 --> 00:34:28,570 indicate an ozone or UV absorber of some 956 00:34:33,180 --> 00:34:31,300 kind in the co2 band so it's gonna be 957 00:34:37,320 --> 00:34:33,190 tough but you know those things may well 958 00:34:40,530 --> 00:34:37,330 be observable if we if we integrate 959 00:34:42,840 --> 00:34:40,540 flung enough so moving on to this face 960 00:34:48,629 --> 00:34:42,850 my fear too early earth-like planets how 961 00:34:50,550 --> 00:34:48,639 am i going for time woody Tom I mean we 962 00:34:53,520 --> 00:34:50,560 started late so 15 were later 15 more 963 00:34:57,930 --> 00:34:53,530 minutes okay so what we did here was in 964 00:35:02,430 --> 00:34:57,940 fact a model a high co2 early Earth's up 965 00:35:05,640 --> 00:35:02,440 to three bars atmospheres using solar 966 00:35:07,530 --> 00:35:05,650 analog spectrum ek draw is a g star like 967 00:35:10,320 --> 00:35:07,540 the Sun but in a very early stage of its 968 00:35:11,700 --> 00:35:10,330 evolution it has a lot of UV so what we 969 00:35:14,640 --> 00:35:11,710 were trying to do was test the 970 00:35:16,470 --> 00:35:14,650 hypothesis that you could in fact from a 971 00:35:18,990 --> 00:35:16,480 co2 rich atmosphere produce a lot of 972 00:35:20,340 --> 00:35:19,000 oxygen within the habitable zone and 973 00:35:21,840 --> 00:35:20,350 that this would be a false positive for 974 00:35:23,250 --> 00:35:21,850 life it would be a way of producing lots 975 00:35:26,070 --> 00:35:23,260 of oxygen that had nothing to do with 976 00:35:28,650 --> 00:35:26,080 life however Jim Cassidy noticed that 977 00:35:29,910 --> 00:35:28,660 when this hypothesis first came out that 978 00:35:31,800 --> 00:35:29,920 the model was used didn't actually 979 00:35:34,350 --> 00:35:31,810 include rain out of oxidized species 980 00:35:37,230 --> 00:35:34,360 which would affect the hydrogen budget 981 00:35:38,820 --> 00:35:37,240 within the planet environment so we went 982 00:35:40,470 --> 00:35:38,830 back and we modified our climate model 983 00:35:42,090 --> 00:35:40,480 or in fact I think he already had it in 984 00:35:43,560 --> 00:35:42,100 there to include the rain out of the 985 00:35:44,950 --> 00:35:43,570 oxidized species and we ran these 986 00:35:48,140 --> 00:35:44,960 experiments again 987 00:35:51,830 --> 00:35:48,150 and so we modeled planets with varying 988 00:35:54,770 --> 00:35:51,840 amounts of o2 very amounts of co2 in 989 00:35:58,190 --> 00:35:54,780 their atmosphere and also early earth 990 00:36:00,620 --> 00:35:58,200 like methane fluxes and around this this 991 00:36:03,740 --> 00:36:00,630 early start so unfortunately this is the 992 00:36:05,060 --> 00:36:03,750 slide I don't think time steps yeah so 993 00:36:07,250 --> 00:36:05,070 they would have been effective under 994 00:36:08,720 --> 00:36:07,260 here I have shown you but I'll just talk 995 00:36:12,580 --> 00:36:08,730 a little bit about this minute red one 996 00:36:16,160 --> 00:36:12,590 here what we saw was that predictably 997 00:36:18,890 --> 00:36:16,170 for the higher co2 fraction planets we 998 00:36:19,970 --> 00:36:18,900 saw very strong absorption from co2 in 999 00:36:21,710 --> 00:36:19,980 the middle read that you wouldn't 1000 00:36:24,560 --> 00:36:21,720 normally see for example in present-day 1001 00:36:26,390 --> 00:36:24,570 earth and leaves these are from hot 1002 00:36:27,650 --> 00:36:26,400 bands and isotopic bands and that was 1003 00:36:29,780 --> 00:36:27,660 also very interesting these were very 1004 00:36:32,270 --> 00:36:29,790 strong signals from either topic bansal 1005 00:36:35,780 --> 00:36:32,280 co2 where the oxygen was actually 1006 00:36:37,220 --> 00:36:35,790 changing its isotope value and so 1007 00:36:39,050 --> 00:36:37,230 potentially this is a way of even 1008 00:36:41,810 --> 00:36:39,060 getting a handle on oxygen isotope 1009 00:36:44,690 --> 00:36:41,820 ratios in the in the atmosphere of the 1010 00:36:46,670 --> 00:36:44,700 stars so the bottom line of all of this 1011 00:36:47,900 --> 00:36:46,680 is we we threw everything we could at 1012 00:36:49,870 --> 00:36:47,910 this planet we gave it every single 1013 00:36:53,810 --> 00:36:49,880 possible chance to create oxygen for us 1014 00:36:56,840 --> 00:36:53,820 we switched off volcanism we we gave it 1015 00:36:59,060 --> 00:36:56,850 a very high UV star we put loads of co2 1016 00:37:00,710 --> 00:36:59,070 in there but with that rain out of 1017 00:37:02,000 --> 00:37:00,720 oxidized species in there there was no 1018 00:37:03,950 --> 00:37:02,010 way we can actually generate a 1019 00:37:06,320 --> 00:37:03,960 reasonable amount of o2 from this model 1020 00:37:08,570 --> 00:37:06,330 so here's the oxygen a van for prison 1021 00:37:10,190 --> 00:37:08,580 earth and here's the oxygen a band for 1022 00:37:12,410 --> 00:37:10,200 every single thing we models so you can 1023 00:37:15,770 --> 00:37:12,420 see that we really couldn't generate any 1024 00:37:17,450 --> 00:37:15,780 detectable signature whatsoever so we're 1025 00:37:19,640 --> 00:37:17,460 kind of a little kick in here in the 1026 00:37:21,650 --> 00:37:19,650 tuber case but nothing nothing 1027 00:37:23,870 --> 00:37:21,660 significant so we could never generate 1028 00:37:26,390 --> 00:37:23,880 anything more than one part in 10 to the 1029 00:37:30,920 --> 00:37:26,400 five of oxygen and the column depth or 1030 00:37:32,300 --> 00:37:30,930 one point and before in the ozone so the 1031 00:37:33,470 --> 00:37:32,310 conclusion the overall conclusion is 1032 00:37:35,480 --> 00:37:33,480 that for planets in the habitable zone 1033 00:37:37,460 --> 00:37:35,490 with an active hydrological cycle is 1034 00:37:40,820 --> 00:37:37,470 probably unlikely we will build up this 1035 00:37:42,230 --> 00:37:40,830 kind of abiotic oxygen and so here's 1036 00:37:43,340 --> 00:37:42,240 sort of like inspection they got 1037 00:37:46,190 --> 00:37:43,350 occluded that I couldn't share 1038 00:37:48,320 --> 00:37:46,200 this is this is the results for planets 1039 00:37:51,520 --> 00:37:48,330 with different amounts of co2 in the 1040 00:37:54,140 --> 00:37:51,530 atmosphere and you notice the the actual 1041 00:37:56,600 --> 00:37:54,150 huge increase in in rayleigh scattering 1042 00:37:58,310 --> 00:37:56,610 for our to barb planet even that's two 1043 00:38:00,170 --> 00:37:58,320 bars of co2 it's actually a totally 1044 00:38:03,170 --> 00:38:00,180 three bar planet because it has almost a 1045 00:38:04,520 --> 00:38:03,180 bar of nitrogen in it as well and so 1046 00:38:07,190 --> 00:38:04,530 this was this was our sort of exotic 1047 00:38:09,620 --> 00:38:07,200 tree bark plant and we see this very 1048 00:38:11,600 --> 00:38:09,630 high Rayleigh scattering you note but at 1049 00:38:13,460 --> 00:38:11,610 point seven six you do not see the 1050 00:38:16,010 --> 00:38:13,470 oxygen a band here we don't see that 1051 00:38:18,200 --> 00:38:16,020 what we do see is lots of signatures 1052 00:38:20,480 --> 00:38:18,210 from the outside as we go into the near 1053 00:38:22,700 --> 00:38:20,490 infrared end of the spectrum in 1054 00:38:25,130 --> 00:38:22,710 particular this one here which I fought 1055 00:38:27,770 --> 00:38:25,140 to get on TPF for a long time are the 1056 00:38:29,600 --> 00:38:27,780 one point 05 micron co2 band which we 1057 00:38:32,930 --> 00:38:29,610 also saw in Venus even at low resolution 1058 00:38:34,910 --> 00:38:32,940 that would be a nice indicator if you 1059 00:38:36,980 --> 00:38:34,920 were to see even if you were to see a 1060 00:38:38,990 --> 00:38:36,990 false positive of oxygen this is fairly 1061 00:38:40,190 --> 00:38:39,000 strong for high co2 atmosphere so you 1062 00:38:43,040 --> 00:38:40,200 might be able to pick that out and know 1063 00:38:44,840 --> 00:38:43,050 that you were being being fooled but but 1064 00:38:47,450 --> 00:38:44,850 in these regions here very strong and 1065 00:38:48,590 --> 00:38:47,460 methane and carbon dioxide and almost to 1066 00:38:50,510 --> 00:38:48,600 the point where you don't even have an 1067 00:38:54,680 --> 00:38:50,520 atmosphere window over large fractions 1068 00:39:00,089 --> 00:38:54,690 of this range of the spectrum so was 1069 00:39:04,420 --> 00:39:02,199 this is the planet in the mid-infrared 1070 00:39:06,429 --> 00:39:04,430 red earth which you should recognize by 1071 00:39:08,319 --> 00:39:06,439 now and then the black spectrum is the 1072 00:39:11,469 --> 00:39:08,329 spectrum of this this three bar to bar 1073 00:39:13,959 --> 00:39:11,479 co2 atmosphere and again we've seen the 1074 00:39:17,109 --> 00:39:13,969 strong bands of isotopes of carbon 1075 00:39:18,939 --> 00:39:17,119 dioxide in it and here this is the only 1076 00:39:20,439 --> 00:39:18,949 atmospheric window we have left where we 1077 00:39:21,670 --> 00:39:20,449 can get deep into the atmosphere and try 1078 00:39:24,309 --> 00:39:21,680 to determine the temperature of the 1079 00:39:25,870 --> 00:39:24,319 planet so on the earth we consider the 1080 00:39:27,880 --> 00:39:25,880 attic window to the right across here 1081 00:39:30,279 --> 00:39:27,890 from eight to thirteen microns but on a 1082 00:39:34,599 --> 00:39:30,289 CO 2 planets narrowed to a tiny tiny 1083 00:39:36,670 --> 00:39:34,609 little range around about 29 microns but 1084 00:39:38,380 --> 00:39:36,680 you note the perviness even though it 1085 00:39:41,349 --> 00:39:38,390 has very similar features as venus is 1086 00:39:42,670 --> 00:39:41,359 also a high co2 atmosphere the depth of 1087 00:39:44,349 --> 00:39:42,680 these features is nowhere near as strong 1088 00:39:46,209 --> 00:39:44,359 and that's again because we're truncated 1089 00:39:47,679 --> 00:39:46,219 by the cloud deck on Venus I can't get 1090 00:39:50,679 --> 00:39:47,689 down to see the full ninety three bars 1091 00:39:54,099 --> 00:39:50,689 of atmosphere there so brightness 1092 00:39:56,410 --> 00:39:54,109 temperatures for these again this is 1093 00:39:58,779 --> 00:39:56,420 interesting because this planet had 1094 00:40:00,219 --> 00:39:58,789 about a 317 Kelvin surface temperature 1095 00:40:02,349 --> 00:40:00,229 but you'll note that the inferred 1096 00:40:04,419 --> 00:40:02,359 brightness temperature is only about 288 1097 00:40:06,339 --> 00:40:04,429 so we really are not seeing to the 1098 00:40:08,559 --> 00:40:06,349 surface of the planet because the co2 1099 00:40:10,059 --> 00:40:08,569 atmosphere is so dense so this is one of 1100 00:40:11,829 --> 00:40:10,069 these warnings I like to put out that 1101 00:40:13,059 --> 00:40:11,839 just because you have an estate window 1102 00:40:16,449 --> 00:40:13,069 doesn't mean you got all the way to the 1103 00:40:17,620 --> 00:40:16,459 surface and sensing the atmosphere so I 1104 00:40:19,029 --> 00:40:17,630 will skip through these because it's 1105 00:40:21,789 --> 00:40:19,039 just a summary of what we've said 1106 00:40:23,380 --> 00:40:21,799 overall and move on to the final face 1107 00:40:25,150 --> 00:40:23,390 with which is the coevolution of 1108 00:40:27,009 --> 00:40:25,160 photosynthesis with the atmospheres of 1109 00:40:29,859 --> 00:40:27,019 extrasolar worlds and this is work this 1110 00:40:32,019 --> 00:40:29,869 make led by Nancy keying for the vpl and 1111 00:40:33,699 --> 00:40:32,029 it's actually involved a lot of our our 1112 00:40:37,329 --> 00:40:33,709 younger scientists here so this is this 1113 00:40:39,130 --> 00:40:37,339 is really great um great work and what 1114 00:40:40,449 --> 00:40:39,140 we're doing here is that before we were 1115 00:40:42,910 --> 00:40:40,459 we're modeling planet so that we could 1116 00:40:44,410 --> 00:40:42,920 look at them from above as an astronomer 1117 00:40:46,719 --> 00:40:44,420 and trying to tell what the planet was 1118 00:40:49,509 --> 00:40:46,729 like here we're looking at them from the 1119 00:40:52,179 --> 00:40:49,519 vegetation the Leafs I view and we're 1120 00:40:53,650 --> 00:40:52,189 looking up at our our star of a 1121 00:40:55,089 --> 00:40:53,660 different spectral type and we're 1122 00:40:56,679 --> 00:40:55,099 looking at how much of that radiation 1123 00:40:59,049 --> 00:40:56,689 makes it through atmospheres of 1124 00:41:00,599 --> 00:40:59,059 different compositions so if you take a 1125 00:41:02,829 --> 00:41:00,609 planet you put it around another star 1126 00:41:04,449 --> 00:41:02,839 what does the leaf see what does the 1127 00:41:06,249 --> 00:41:04,459 microbe see at the surface of the planet 1128 00:41:07,779 --> 00:41:06,259 and what does that tell you about where 1129 00:41:09,460 --> 00:41:07,789 it's likely to choose to put its 1130 00:41:11,510 --> 00:41:09,470 pigments for photosynthesis 1131 00:41:13,640 --> 00:41:11,520 so we use planetary atmosphere 1132 00:41:16,039 --> 00:41:13,650 compositions and a stellar spectra for 1133 00:41:18,079 --> 00:41:16,049 earth-like planets so those with the one 1134 00:41:20,390 --> 00:41:18,089 x of the present amp straight level of 1135 00:41:22,220 --> 00:41:20,400 oxygen and also for near anoxic planners 1136 00:41:23,539 --> 00:41:22,230 that only had one part in 10 to the 5 of 1137 00:41:25,789 --> 00:41:23,549 the current level of oxygen and their 1138 00:41:27,440 --> 00:41:25,799 atmospheres now we put them around FG k 1139 00:41:29,210 --> 00:41:27,450 and m stars so these are the spectra 1140 00:41:31,099 --> 00:41:29,220 I've just shown you which we use for a 1141 00:41:32,690 --> 00:41:31,109 different purpose when we run the 1142 00:41:34,280 --> 00:41:32,700 radiative transfer model we generate the 1143 00:41:36,289 --> 00:41:34,290 spectrum of the top and the spiracles 1144 00:41:38,690 --> 00:41:36,299 service so we just took that 1145 00:41:41,089 --> 00:41:38,700 product and that's what we use so we 1146 00:41:43,339 --> 00:41:41,099 derived the incident spectral photon 1147 00:41:44,809 --> 00:41:43,349 flux densities that's important not the 1148 00:41:46,700 --> 00:41:44,819 radiance but the actual number of 1149 00:41:48,020 --> 00:41:46,710 photons that are coming in because 1150 00:41:50,839 --> 00:41:48,030 that's what plants care about 1151 00:41:53,450 --> 00:41:50,849 photosynthesis is a photon numerical 1152 00:41:55,039 --> 00:41:53,460 process and so that's what we had a look 1153 00:41:57,589 --> 00:41:55,049 at we did that for planetary services 1154 00:41:59,599 --> 00:41:57,599 and underwater as well we identified for 1155 00:42:01,250 --> 00:41:59,609 a synthetically relevant radiation and 1156 00:42:03,319 --> 00:42:01,260 looked at the likely pigment peak 1157 00:42:05,000 --> 00:42:03,329 adsorbents and also made an attempt to 1158 00:42:07,160 --> 00:42:05,010 calculate planetary productivity and 1159 00:42:08,839 --> 00:42:07,170 that is going to be published in the m 1160 00:42:10,490 --> 00:42:08,849 star special edition of astrobiology 1161 00:42:11,900 --> 00:42:10,500 which is coming out in March and that 1162 00:42:13,520 --> 00:42:11,910 should be a really great addition by the 1163 00:42:17,030 --> 00:42:13,530 way it's got lots of really good papers 1164 00:42:20,180 --> 00:42:17,040 in it so here um does it for me have a 1165 00:42:22,130 --> 00:42:20,190 look at me this has the spectrum that's 1166 00:42:24,440 --> 00:42:22,140 insulin at the top of our atmosphere on 1167 00:42:26,210 --> 00:42:24,450 the Sun this is the average spectrum 1168 00:42:28,370 --> 00:42:26,220 that in fact makes its way through the 1169 00:42:31,940 --> 00:42:28,380 atmosphere and what we noticed is that 1170 00:42:34,220 --> 00:42:31,950 right ozone takes to absorb out here and 1171 00:42:36,770 --> 00:42:34,230 we'll the actual peak of the 1172 00:42:38,450 --> 00:42:36,780 radiation from what is he could incident 1173 00:42:39,980 --> 00:42:38,460 at the top of the atmosphere to what is 1174 00:42:43,549 --> 00:42:39,990 peak at the surface of the atmosphere 1175 00:42:45,829 --> 00:42:43,559 actually shifts towards the red and so 1176 00:42:47,780 --> 00:42:45,839 what Nancy did was was put together a 1177 00:42:50,809 --> 00:42:47,790 series of rules Nancy and collaborators 1178 00:42:52,880 --> 00:42:50,819 of where we might expect pigments for 1179 00:42:54,829 --> 00:42:52,890 photosynthesis to curve and the first 1180 00:42:56,329 --> 00:42:54,839 characteristic you look for is the 1181 00:43:00,200 --> 00:42:56,339 wavelength of peak incident photon flux 1182 00:43:01,400 --> 00:43:00,210 at the surface okay so so again we found 1183 00:43:04,460 --> 00:43:01,410 that the atmosphere actually multiply 1184 00:43:05,450 --> 00:43:04,470 that intended to shift it we also say 1185 00:43:07,150 --> 00:43:05,460 that you should look for the longest 1186 00:43:10,010 --> 00:43:07,160 wavelengths within the radiation window 1187 00:43:13,039 --> 00:43:10,020 also for these core antenna or or 1188 00:43:15,200 --> 00:43:13,049 pigments that are satellite pigments 1189 00:43:16,460 --> 00:43:15,210 that are used and these longest 1190 00:43:18,770 --> 00:43:16,470 wavelength is so that you can capture 1191 00:43:20,150 --> 00:43:18,780 the the photon fairly easily the 1192 00:43:21,319 --> 00:43:20,160 shortest wavelength is 1193 00:43:23,329 --> 00:43:21,329 there because it's high energy and 1194 00:43:25,430 --> 00:43:23,339 therefore valuable when you calf get it 1195 00:43:26,750 --> 00:43:25,440 down to the photon Center so there's the 1196 00:43:28,190 --> 00:43:26,760 peak because there's lots of stuff there 1197 00:43:29,960 --> 00:43:28,200 and then you also have accessory 1198 00:43:32,930 --> 00:43:29,970 pigments on either side satellites 1199 00:43:34,970 --> 00:43:32,940 essentially that also funnel photons 1200 00:43:38,120 --> 00:43:34,980 into this process to help actually do 1201 00:43:39,349 --> 00:43:38,130 photosynthesis so what we found then was 1202 00:43:41,180 --> 00:43:39,359 that says the ozone ship rebound 1203 00:43:42,789 --> 00:43:41,190 strongly affected the pig surface 1204 00:43:44,720 --> 00:43:42,799 radiation has shifted it over this way 1205 00:43:47,390 --> 00:43:44,730 that's actually pretty much where 1206 00:43:50,089 --> 00:43:47,400 chlorophyll-a operates at least on the 1207 00:43:51,799 --> 00:43:50,099 red end and Nancy and collaborators have 1208 00:43:54,109 --> 00:43:51,809 postulated that that made fun fact be 1209 00:43:55,609 --> 00:43:54,119 why plants are green they're smart they 1210 00:43:57,319 --> 00:43:55,619 actually know where the peak photon flux 1211 00:44:00,309 --> 00:43:57,329 is and they've gone over there to do 1212 00:44:02,450 --> 00:44:00,319 their photosynthesis towards the red 1213 00:44:04,069 --> 00:44:02,460 what we also looked at with surface 1214 00:44:06,579 --> 00:44:04,079 incident flux versus the atmospheric 1215 00:44:09,319 --> 00:44:06,589 composition see how it changed again 1216 00:44:11,210 --> 00:44:09,329 ozone was affecting the spectrum what 1217 00:44:13,309 --> 00:44:11,220 was reaching surface so here we kind of 1218 00:44:16,430 --> 00:44:13,319 had the average are incident and then 1219 00:44:18,020 --> 00:44:16,440 the average on the surface and again 1220 00:44:19,849 --> 00:44:18,030 there's a chick eating out of here in 1221 00:44:21,770 --> 00:44:19,859 the f star spectrum from the ozone very 1222 00:44:23,720 --> 00:44:21,780 strong ozone absorption and what that 1223 00:44:26,269 --> 00:44:23,730 did was actually ship keep photon flux 1224 00:44:28,460 --> 00:44:26,279 to the blue for the X star so depending 1225 00:44:29,809 --> 00:44:28,470 on where the ozone fell relative to the 1226 00:44:31,250 --> 00:44:29,819 stellar spectrum radiation it would 1227 00:44:33,170 --> 00:44:31,260 actually shift it over to the blue or 1228 00:44:35,240 --> 00:44:33,180 over to the red so in the X da case it 1229 00:44:36,890 --> 00:44:35,250 shifted it to the blue every other 1230 00:44:39,200 --> 00:44:36,900 planet is shipped a bit more towards the 1231 00:44:41,359 --> 00:44:39,210 red and at a case of the M star planets 1232 00:44:43,549 --> 00:44:41,369 they had so much absorption from species 1233 00:44:45,890 --> 00:44:43,559 their atmospheres including water and 1234 00:44:47,930 --> 00:44:45,900 methane that there were very quantized 1235 00:44:50,599 --> 00:44:47,940 windows available for the pigments to 1236 00:44:53,510 --> 00:44:50,609 work in and other areas where almost no 1237 00:44:55,400 --> 00:44:53,520 radiation go to the surface so this is a 1238 00:44:59,000 --> 00:44:55,410 little bit scary but what it's showing 1239 00:45:01,010 --> 00:44:59,010 overall is the peak surface photon flux 1240 00:45:03,079 --> 00:45:01,020 for Earth's around strands of different 1241 00:45:05,180 --> 00:45:03,089 spectral type and here we see that peak 1242 00:45:06,980 --> 00:45:05,190 photon flux the f star push over here to 1243 00:45:09,980 --> 00:45:06,990 the blue but for everything else the 1244 00:45:11,359 --> 00:45:09,990 peak photon flux is either in the red or 1245 00:45:14,440 --> 00:45:11,369 it's like even move over into the 1246 00:45:17,870 --> 00:45:14,450 infrared for some of the m star planets 1247 00:45:19,190 --> 00:45:17,880 the other thing we looked at is what you 1248 00:45:21,230 --> 00:45:19,200 would see if you are an organism 1249 00:45:23,030 --> 00:45:21,240 underwater on one of these planets 1250 00:45:24,980 --> 00:45:23,040 the main conclusion is that you probably 1251 00:45:26,570 --> 00:45:24,990 don't want to be operating doing your 1252 00:45:28,130 --> 00:45:26,580 photon catching anywhere longer with one 1253 00:45:30,380 --> 00:45:28,140 point one micron in these particular 1254 00:45:32,240 --> 00:45:30,390 cases but it also gave us an idea of 1255 00:45:34,040 --> 00:45:32,250 where the pigments might be especially 1256 00:45:35,930 --> 00:45:34,050 the M star planets if we could 1257 00:45:38,359 --> 00:45:35,940 potentially push them over to infrared 1258 00:45:45,530 --> 00:45:38,369 radiation infrared regions and that 1259 00:45:46,880 --> 00:45:45,540 would be particularly valuable ya know 1260 00:45:48,260 --> 00:45:46,890 we did we did also look at different 1261 00:45:50,330 --> 00:45:48,270 water depths I don't have the plots but 1262 00:45:52,690 --> 00:45:50,340 doing that them in the paper yeah so we 1263 00:45:55,760 --> 00:45:52,700 went down and in fact I'll show you um 1264 00:45:58,520 --> 00:45:55,770 safety levels in a minute okay for the 1265 00:45:59,960 --> 00:45:58,530 different ones and here we go so am i if 1266 00:46:02,660 --> 00:45:59,970 the water'd that's worth their safety 1267 00:46:04,970 --> 00:46:02,670 and what we did here was for the MCR 1268 00:46:06,950 --> 00:46:04,980 planets there around a star that's 1269 00:46:09,440 --> 00:46:06,960 potentially active and flaring so the 1270 00:46:11,000 --> 00:46:09,450 question is is it possible to evolve and 1271 00:46:12,680 --> 00:46:11,010 find a level within water where you're 1272 00:46:14,660 --> 00:46:12,690 safe from flaring even the worst of the 1273 00:46:17,300 --> 00:46:14,670 flaring but still have enough photons to 1274 00:46:19,400 --> 00:46:17,310 be able to do photosynthesis and what we 1275 00:46:21,560 --> 00:46:19,410 found was that essentially as long as 1276 00:46:24,290 --> 00:46:21,570 the flares don't exceed this energy here 1277 00:46:26,210 --> 00:46:24,300 just I think kind of mid-range this is 1278 00:46:28,190 --> 00:46:26,220 the extreme for a treo I believe the 1279 00:46:29,810 --> 00:46:28,200 extreme that's been seen but as long as 1280 00:46:31,849 --> 00:46:29,820 you don't exceed this range of flare 1281 00:46:33,140 --> 00:46:31,859 then you can survive okay on the surface 1282 00:46:34,640 --> 00:46:33,150 of an M star planet even in the 1283 00:46:36,980 --> 00:46:34,650 habitable zone you don't need water to 1284 00:46:38,630 --> 00:46:36,990 protect you beyond this energy you do 1285 00:46:40,520 --> 00:46:38,640 need water and this is the depth of 1286 00:46:43,400 --> 00:46:40,530 water that you need so the bottom line 1287 00:46:44,660 --> 00:46:43,410 was that it is long as you a 9.1 meters 1288 00:46:46,220 --> 00:46:44,670 under water and I'm sure that point one 1289 00:46:48,140 --> 00:46:46,230 is really important but if you remember 1290 00:46:49,580 --> 00:46:48,150 when leaders have ordered you would 1291 00:46:53,060 --> 00:46:49,590 still escape the worst of the flare 1292 00:46:55,400 --> 00:46:53,070 energy from an M star and still have 1293 00:46:57,710 --> 00:46:55,410 enough photons in facts to support 1294 00:46:59,599 --> 00:46:57,720 something like red algae by more than a 1295 00:47:01,070 --> 00:46:59,609 factor of 10 so that was really 1296 00:47:03,230 --> 00:47:01,080 interesting you could actually find a 1297 00:47:06,080 --> 00:47:03,240 safe zone but still be able to to make 1298 00:47:07,130 --> 00:47:06,090 your food and so that's the end of the 1299 00:47:09,920 --> 00:47:07,140 talk here and these are our major 1300 00:47:11,210 --> 00:47:09,930 conclusions planetary environmental 1301 00:47:13,010 --> 00:47:11,220 modeling has shown us that you know 1302 00:47:14,420 --> 00:47:13,020 different planetary compositions and 1303 00:47:16,820 --> 00:47:14,430 environmental characteristics can be 1304 00:47:19,880 --> 00:47:16,830 determined from discovery spectra larger 1305 00:47:21,590 --> 00:47:19,890 waveland coverage always are useful and 1306 00:47:22,940 --> 00:47:21,600 of course we as scientists are always 1307 00:47:23,750 --> 00:47:22,950 putting the engineers to give us more in 1308 00:47:26,690 --> 00:47:23,760 the way but 1309 00:47:28,640 --> 00:47:26,700 but certainly a very important for for 1310 00:47:30,680 --> 00:47:28,650 census of greenhouse gases finding 1311 00:47:31,970 --> 00:47:30,690 metabolites and being able to to be 1312 00:47:34,340 --> 00:47:31,980 certain that what you've seen at low 1313 00:47:36,380 --> 00:47:34,350 resolution is what you think it is also 1314 00:47:40,070 --> 00:47:36,390 the planets UV environment affected what 1315 00:47:41,780 --> 00:47:40,080 we saw in very non-intuitive ways but 1316 00:47:43,670 --> 00:47:41,790 also the fact that earth-like planets as 1317 00:47:46,010 --> 00:47:43,680 long as you had a oxygen ozone layers 1318 00:47:48,020 --> 00:47:46,020 would form in response to the spectrum 1319 00:47:50,830 --> 00:47:48,030 of the parent star in such a way that we 1320 00:47:52,820 --> 00:47:50,840 obtained habitability on the surface 1321 00:47:54,110 --> 00:47:52,830 also the fact that planets around M 1322 00:47:56,300 --> 00:47:54,120 stars can potentially build up these 1323 00:47:57,650 --> 00:47:56,310 other gases that are biomarkers because 1324 00:48:00,290 --> 00:47:57,660 they have longer lifetimes in those 1325 00:48:03,230 --> 00:48:00,300 atmospheres abiotic formation of o2 and 1326 00:48:04,490 --> 00:48:03,240 o3 in high CO 2 atmospheres is unlikely 1327 00:48:07,220 --> 00:48:04,500 as long as you have an act of 1328 00:48:09,740 --> 00:48:07,230 hydrological cycle and finally the 1329 00:48:11,960 --> 00:48:09,750 surface photon flux that you see is 1330 00:48:12,940 --> 00:48:11,970 planetary environment dependent depends 1331 00:48:15,110 --> 00:48:12,950 on what's actually in your atmosphere 1332 00:48:16,850 --> 00:48:15,120 strong dependence on ozone being there 1333 00:48:18,860 --> 00:48:16,860 as well and it will likely govern the 1334 00:48:20,420 --> 00:48:18,870 most advantageous pigments for 1335 00:48:22,790 --> 00:48:20,430 photosynthesis for planets around stars 1336 00:48:29,240 --> 00:48:22,800 a different spectral type so I will 1337 00:48:33,390 --> 00:48:31,200 well thank you very much for that 1338 00:48:45,950 --> 00:48:33,400 wide-ranging and fascinating talk I'm 1339 00:49:02,070 --> 00:48:48,300 narrowband just want to treat your 1340 00:49:03,900 --> 00:49:02,080 customers I didn't hear the left yeah so 1341 00:49:05,820 --> 00:49:03,910 what was the very last day it seems like 1342 00:49:09,510 --> 00:49:05,830 maybe you would do better signals and I 1343 00:49:11,940 --> 00:49:09,520 don't get you you would and and there 1344 00:49:13,410 --> 00:49:11,950 are people who have done that work and 1345 00:49:15,089 --> 00:49:13,420 West tribe is one of them and in the 1346 00:49:17,160 --> 00:49:15,099 demo al paper which is a classic browser 1347 00:49:18,960 --> 00:49:17,170 u21 they talk about matched filter bands 1348 00:49:20,190 --> 00:49:18,970 for these types of things I have a 1349 00:49:24,000 --> 00:49:20,200 different view I actually don't like 1350 00:49:26,400 --> 00:49:24,010 that and here's why because TPF is going 1351 00:49:28,109 --> 00:49:26,410 to be an instrument of discovery and as 1352 00:49:30,240 --> 00:49:28,119 I said these plants may be completely 1353 00:49:31,740 --> 00:49:30,250 unlike anything we've ever seen so I 1354 00:49:33,660 --> 00:49:31,750 think it's a little bit dangerous to 1355 00:49:36,359 --> 00:49:33,670 have nothing but mesh filter bands for 1356 00:49:37,620 --> 00:49:36,369 things we expect to see one thing I 1357 00:49:39,690 --> 00:49:37,630 didn't show you here as well is that 1358 00:49:41,609 --> 00:49:39,700 that even though you might know roughly 1359 00:49:43,710 --> 00:49:41,619 how wide the feature is going to be to 1360 00:49:45,690 --> 00:49:43,720 match the band you probably never know 1361 00:49:48,540 --> 00:49:45,700 how wide the continuum is going to be um 1362 00:49:50,370 --> 00:49:48,550 and and so the more species you have in 1363 00:49:52,020 --> 00:49:50,380 in the in the atmosphere and in the 1364 00:49:53,790 --> 00:49:52,030 spectrum the more your continuum tends 1365 00:49:55,109 --> 00:49:53,800 to narrow down in some cases that may be 1366 00:49:56,760 --> 00:49:55,119 the Narrows feature in the spectrum 1367 00:49:59,190 --> 00:49:56,770 those co2 planets the other continuum is 1368 00:50:00,870 --> 00:49:59,200 really tiny so I'm more of the 1369 00:50:03,359 --> 00:50:00,880 philosophy that that this thing really 1370 00:50:06,329 --> 00:50:03,369 should be a broad wavelength capability 1371 00:50:07,589 --> 00:50:06,339 and if binning is required which I agree 1372 00:50:09,540 --> 00:50:07,599 is definitely the better way to go for 1373 00:50:11,250 --> 00:50:09,550 signal-to-noise it would be better if we 1374 00:50:14,099 --> 00:50:11,260 had a wider wavelength capability that 1375 00:50:17,070 --> 00:50:14,109 could be bend to get signal to noise but 1376 00:50:19,349 --> 00:50:17,080 should we be deliriously lucky to get a 1377 00:50:21,060 --> 00:50:19,359 bright terrestrial planet nearby that we 1378 00:50:22,770 --> 00:50:21,070 at least had the spectral capability to 1379 00:50:24,839 --> 00:50:22,780 then go after that one target with as 1380 00:50:26,670 --> 00:50:24,849 much structural range as possible so 1381 00:50:28,859 --> 00:50:26,680 that's the way I'd rather go is there 1382 00:50:31,170 --> 00:50:28,869 some kind of after instrument binning of 1383 00:50:33,240 --> 00:50:31,180 the data but again that requires that we 1384 00:50:34,950 --> 00:50:33,250 have really low Reed noise and I'm not 1385 00:50:36,089 --> 00:50:34,960 sure those detectors are built yet but 1386 00:50:37,450 --> 00:50:36,099 I'm sure we have a lot of time to 1387 00:50:40,000 --> 00:50:37,460 develop things so 1388 00:50:42,790 --> 00:50:40,010 hopefully we'll work on that other 1389 00:50:47,890 --> 00:50:42,800 questions yes have a related question 1390 00:50:50,589 --> 00:50:47,900 how much of an issue is red shift uh 1391 00:50:51,730 --> 00:50:50,599 negligible as far as i know that's it's 1392 00:50:55,150 --> 00:50:51,740 not a big deal at all they're really 1393 00:50:57,190 --> 00:50:55,160 nearby yeah weird i mean the the most 1394 00:51:00,820 --> 00:50:57,200 distant things are going to be at you 1395 00:51:02,920 --> 00:51:00,830 know about 10-15 parsecs you know it may 1396 00:51:04,660 --> 00:51:02,930 be out to 45 at the very outer limit but 1397 00:51:06,490 --> 00:51:04,670 we really are extremely close in the 1398 00:51:10,839 --> 00:51:06,500 solar neighborhood firth for trying to 1399 00:51:15,579 --> 00:51:10,849 find these sorts of things no no it 1400 00:51:18,099 --> 00:51:15,589 doesn't other questions yes people where 1401 00:51:21,490 --> 00:51:18,109 you said the DNA dangers of uncle Timon 1402 00:51:23,770 --> 00:51:21,500 and see entries for the hen work um no 1403 00:51:25,420 --> 00:51:23,780 and I'm not sure I'd have to talk to 1404 00:51:26,740 --> 00:51:25,430 aunty I think we may have calculated 1405 00:51:28,150 --> 00:51:26,750 this but we didn't publish them so i 1406 00:51:29,440 --> 00:51:28,160 didn't i didn't take them out of video 1407 00:51:34,390 --> 00:51:29,450 but if you want them like that we can 1408 00:51:38,230 --> 00:51:34,400 get them remember uh I think it's pretty 1409 00:51:40,270 --> 00:51:38,240 negligible overall even at the surface 1410 00:51:42,010 --> 00:51:40,280 and even if we don't produce very much 1411 00:51:45,010 --> 00:51:42,020 ozone I think it really wasn't a major 1412 00:51:47,980 --> 00:51:45,020 concern some of the higher energy a uva 1413 00:51:49,359 --> 00:51:47,990 can get through but but for the rest of 1414 00:51:51,339 --> 00:51:49,369 it i think it was down by like a factor 1415 00:51:52,990 --> 00:51:51,349 of twenty or something versus earth for 1416 00:51:57,760 --> 00:51:53,000 the rest of the spectrum i believe that 1417 00:52:02,170 --> 00:51:57,770 was right ha open up the business DNA 1418 00:52:05,349 --> 00:52:02,180 damages what age of story that would 1419 00:52:09,970 --> 00:52:05,359 change certainly for an early she starts 1420 00:52:12,579 --> 00:52:09,980 early early history how did you I think 1421 00:52:14,849 --> 00:52:12,589 the f star was probably older and I mean 1422 00:52:19,570 --> 00:52:14,859 we plotted the UV that we had for those 1423 00:52:21,550 --> 00:52:19,580 the the mville the a dealio one was 1424 00:52:23,470 --> 00:52:21,560 actually you know outrageously active I 1425 00:52:25,180 --> 00:52:23,480 didn't I didn't show that one the case 1426 00:52:26,859 --> 00:52:25,190 how I can't remember what age it wants 1427 00:52:28,270 --> 00:52:26,869 but that's certainly true that you know 1428 00:52:30,790 --> 00:52:28,280 very early on you would have the higher 1429 00:52:32,170 --> 00:52:30,800 UV fluxes in the activity so Sofia 1430 00:52:33,880 --> 00:52:32,180 fluxes we calculate a word for the age 1431 00:52:35,200 --> 00:52:33,890 of the stars that we chose and I can't 1432 00:52:36,930 --> 00:52:35,210 remember exactly what they were but I 1433 00:52:39,490 --> 00:52:36,940 think their order of billions of years 1434 00:52:41,370 --> 00:52:39,500 can you looked into absorption spectra 1435 00:52:46,180 --> 00:52:41,380 that we might hope to get as we 1436 00:52:48,190 --> 00:52:46,190 with a chesty for transiting planets I 1437 00:52:49,690 --> 00:52:48,200 haven't looked into that but Giovanna 1438 00:52:51,730 --> 00:52:49,700 tinetti who is one of our former 1439 00:52:53,680 --> 00:52:51,740 postdocs and I was working EFA in Paris 1440 00:52:56,650 --> 00:52:53,690 she's specifically using these types of 1441 00:52:59,080 --> 00:52:56,660 models to look at trends spectra through 1442 00:53:01,420 --> 00:52:59,090 terrestrial planet atmosphere for these 1443 00:53:03,940 --> 00:53:01,430 types of transits as well and also for 1444 00:53:06,610 --> 00:53:03,950 Jovians so she's working on that we are 1445 00:53:08,320 --> 00:53:06,620 not what do you suggest it to me that 1446 00:53:10,840 --> 00:53:08,330 these spectral searches should include 1447 00:53:15,490 --> 00:53:10,850 designer molecules of advanced life like 1448 00:53:16,990 --> 00:53:15,500 free on 06 um yeah um okay I'm 1449 00:53:18,940 --> 00:53:17,000 interesting respond to that he's are 1450 00:53:20,560 --> 00:53:18,950 your doober that up um yes that's 1451 00:53:21,910 --> 00:53:20,570 conceivable as some of these have very 1452 00:53:23,800 --> 00:53:21,920 narrow features of Khmer only really 1453 00:53:24,910 --> 00:53:23,810 seen it at relatively high resolution so 1454 00:53:26,290 --> 00:53:24,920 some of them are difficult to detect 1455 00:53:27,610 --> 00:53:26,300 others are so diffuse they're also 1456 00:53:31,390 --> 00:53:27,620 difficult to detect on low 1457 00:53:33,220 --> 00:53:31,400 signal-to-noise my my maybe flip but but 1458 00:53:34,420 --> 00:53:33,230 this is the way I feel answer is first 1459 00:53:38,770 --> 00:53:34,430 of all we really want to find these 1460 00:53:40,750 --> 00:53:38,780 things and secondly I think that 1461 00:53:42,730 --> 00:53:40,760 astronomically speaking unless the 1462 00:53:45,100 --> 00:53:42,740 civilization is really dumb and kills 1463 00:53:46,780 --> 00:53:45,110 itself those signatures should only be 1464 00:53:49,180 --> 00:53:46,790 around for a very small period of time 1465 00:53:51,130 --> 00:53:49,190 until the civilization realizes what the 1466 00:53:53,020 --> 00:53:51,140 heck is doing and then scrubs them out 1467 00:53:54,190 --> 00:53:53,030 of the atmosphere and I think in the 1468 00:53:55,690 --> 00:53:54,200 case of the earth who would have seen 1469 00:53:58,210 --> 00:53:55,700 these build up and then we will see them 1470 00:53:59,920 --> 00:53:58,220 go down on a very short span compared 1471 00:54:01,330 --> 00:53:59,930 with the age of the star and so 1472 00:54:04,120 --> 00:54:01,340 astronomically when we go and look out 1473 00:54:05,050 --> 00:54:04,130 for TPF you know around other stars I 1474 00:54:06,760 --> 00:54:05,060 don't think there's a very high 1475 00:54:08,800 --> 00:54:06,770 statistical probability that will see it 1476 00:54:10,300 --> 00:54:08,810 unless they really do destroy their 1477 00:54:11,850 --> 00:54:10,310 peril and I would argue just bring the 1478 00:54:13,960 --> 00:54:11,860 equivalent of your narrow spectral 1479 00:54:16,270 --> 00:54:13,970 signature big you that you don't define 1480 00:54:17,380 --> 00:54:16,280 too much I'll chillin on earth yeah so 1481 00:54:18,640 --> 00:54:17,390 that's the other thing if we hadn't 1482 00:54:20,350 --> 00:54:18,650 filled matched filter bands you'd never 1483 00:54:31,719 --> 00:54:20,360 see those so again if he nice to have 1484 00:54:36,739 --> 00:54:34,459 right we do have some without an oxygen 1485 00:54:39,170 --> 00:54:36,749 carbonyl sulfide can be measured in 1486 00:54:40,849 --> 00:54:39,180 those particular wavelength ranges they 1487 00:54:44,120 --> 00:54:40,859 are in the same regime there was water 1488 00:54:45,229 --> 00:54:44,130 in methane so if water a methane at 1489 00:54:47,420 --> 00:54:45,239 present and if you want a habitable 1490 00:54:50,390 --> 00:54:47,430 planet water will be that does make it 1491 00:54:52,339 --> 00:54:50,400 quite difficult to pull out so so they 1492 00:54:53,959 --> 00:54:52,349 are there that there theoretically we 1493 00:54:55,819 --> 00:54:53,969 could observe them but it may be 1494 00:54:57,920 --> 00:54:55,829 difficult on actual habitable planets 1495 00:54:59,599 --> 00:54:57,930 ironically on an uninhabited planet they 1496 00:55:00,799 --> 00:54:59,609 stick out like a sore thumb one on Venus 1497 00:55:03,559 --> 00:55:00,809 you know they're much much easier to 1498 00:55:05,329 --> 00:55:03,569 detect overall but certainly something 1499 00:55:07,160 --> 00:55:05,339 we could look for and I know Carl has 1500 00:55:08,959 --> 00:55:07,170 also been looking at dimethyl sulfide 1501 00:55:10,839 --> 00:55:08,969 for example as an output and it has a 1502 00:55:14,509 --> 00:55:10,849 very strong feature also in that range 1503 00:55:31,820 --> 00:55:14,519 I'm actually asking she was it let's 1504 00:55:41,640 --> 00:55:39,630 go with you I assume you're gonna see a 1505 00:55:43,020 --> 00:55:41,650 lot of methane right so they'll be 1506 00:55:45,360 --> 00:55:43,030 methane and water which would actually 1507 00:55:46,800 --> 00:55:45,370 serve to mask a lot of that we could 1508 00:55:47,940 --> 00:55:46,810 certainly try modeling it and see if 1509 00:55:49,230 --> 00:55:47,950 there's anything there that that makes 1510 00:55:50,790 --> 00:55:49,240 its way out i'm trying to think of this 1511 00:55:54,900 --> 00:55:50,800 anything up in that way it would be I 1512 00:55:57,210 --> 00:55:54,910 think extremely all of it okay and well 1513 00:56:05,250 --> 00:55:57,220 you see my goal to biomass and you had 1514 00:56:06,300 --> 00:56:05,260 working at any happens a lot right well 1515 00:56:08,070 --> 00:56:06,310 you saw what happened when we had a 1516 00:56:09,840 --> 00:56:08,080 dense co2 atmosphere mean pretty much 1517 00:56:13,470 --> 00:56:09,850 most of that vision the men afraid with 1518 00:56:15,150 --> 00:56:13,480 eaten away by co2 absorption but I mean 1519 00:56:16,710 --> 00:56:15,160 I think I can't answer that without 1520 00:56:18,600 --> 00:56:16,720 doing a model to see if something could 1521 00:56:20,250 --> 00:56:18,610 slip between the gaps between co2 and 1522 00:56:22,530 --> 00:56:20,260 methane that might be detectable like 1523 00:56:24,900 --> 00:56:22,540 so2 or the other thing too is the 1524 00:56:26,640 --> 00:56:24,910 arguments Jim casting also is pointed 1525 00:56:28,980 --> 00:56:26,650 this out if that the sulfur gas is tend 1526 00:56:30,420 --> 00:56:28,990 to be very soluble in water and so if 1527 00:56:31,440 --> 00:56:30,430 you had an ocean you might end up 1528 00:56:34,020 --> 00:56:31,450 scrubbing them out of the atmosphere 1529 00:56:36,330 --> 00:56:34,030 pretty fast but as in the case of oxygen 1530 00:56:37,710 --> 00:56:36,340 sinks can be overwhelmed and so you know 1531 00:56:39,750 --> 00:56:37,720 you might argue that potentially you 1532 00:56:41,070 --> 00:56:39,760 could build up sulfur dioxide the other 1533 00:56:43,530 --> 00:56:41,080 thing is discriminating that from 1534 00:56:45,480 --> 00:56:43,540 volcanism at that time because the 1535 00:56:47,490 --> 00:56:45,490 location also put a lot of sulfur gases 1536 00:56:48,540 --> 00:56:47,500 into the atmosphere other thing is life 1537 00:56:50,130 --> 00:56:48,550 to himself against this in the 1538 00:56:52,470 --> 00:56:50,140 atmosphere can be fairly short against 1539 00:56:55,170 --> 00:56:52,480 catalysis so depending on what haze we 1540 00:56:56,550 --> 00:56:55,180 have available so it's a toughy but I 1541 00:57:04,590 --> 00:56:56,560 mean we could we could try modeling it 1542 00:57:10,420 --> 00:57:07,660 that we can get you so we have a 1543 00:57:12,610 --> 00:57:10,430 question from outside Seattle are are 1544 00:57:19,830 --> 00:57:12,620 there any questions from Ames or any 1545 00:57:22,620 --> 00:57:19,840 other we don't have any questions here 1546 00:57:26,890 --> 00:57:22,630 so we have time for one or two more here 1547 00:57:29,650 --> 00:57:26,900 yeah well if students and I your 1548 00:57:38,080 --> 00:57:29,660 region/sector compared to observe 1549 00:57:39,970 --> 00:57:38,090 specter of the earth the Sun right well 1550 00:57:41,590 --> 00:57:39,980 we have all of the Earth's spectra that 1551 00:57:44,290 --> 00:57:41,600 I should have been validated against 1552 00:57:46,330 --> 00:57:44,300 discount observations from the test 1553 00:57:48,580 --> 00:57:46,340 instrument whereas it was going to Mars 1554 00:57:50,710 --> 00:57:48,590 it looks back and took a spectra and 1555 00:57:52,630 --> 00:57:50,720 then in the optical invalidated against 1556 00:57:54,460 --> 00:57:52,640 earth science retro Louise party at a 1557 00:57:56,440 --> 00:57:54,470 restaurant your conference contained 1558 00:57:59,200 --> 00:57:56,450 left and three participants at this time 1559 00:58:01,270 --> 00:57:59,210 if you would like to continue that's our 1560 00:58:06,460 --> 00:58:01,280 one yeah for the conference will be 1561 00:58:08,050 --> 00:58:06,470 terminated spacecraft observations of 1562 00:58:09,100 --> 00:58:08,060 discouraged data coming back so that's 1563 00:58:12,340 --> 00:58:09,110 the first thing we do before we do 1564 00:58:16,330 --> 00:58:12,350 anything else and you know all those any 1565 00:58:18,460 --> 00:58:16,340 hacking yeah you do have to get the 1566 00:58:20,590 --> 00:58:18,470 right cloud balance which is variable on 1567 00:58:22,300 --> 00:58:20,600 the day and so what we try to do is go 1568 00:58:24,490 --> 00:58:22,310 and get the motor stator for the cloud 1569 00:58:26,050 --> 00:58:24,500 on the day so that we have you know at 1570 00:58:28,330 --> 00:58:26,060 least some good approximation of what's 1571 00:58:30,070 --> 00:58:28,340 going on and that's that's what we try 1572 00:58:31,660 --> 00:58:30,080 to use but certainly if you were doing 1573 00:58:33,460 --> 00:58:31,670 it just cold not knowing what the cloud 1574 00:58:36,310 --> 00:58:33,470 distribution and type was on the day 1575 00:58:38,380 --> 00:58:36,320 then you would have to tweak cloud types 1576 00:58:40,060 --> 00:58:38,390 and abundances to try and get a match to 1577 00:58:41,579 --> 00:58:40,070 the discouraged entrance but that's the 1578 00:58:46,510 --> 00:58:41,589 main variable is a cloud