1 00:00:09,190 --> 00:00:06,750 [Music] 2 00:00:10,629 --> 00:00:09,200 thank you again to the organizers as 3 00:00:12,310 --> 00:00:10,639 everyone has said it's absolutely 4 00:00:14,589 --> 00:00:12,320 required to thank them for winning such 5 00:00:16,030 --> 00:00:14,599 a great show here and especially to Rhea 6 00:00:19,240 --> 00:00:16,040 and Philippa for dealing with all of my 7 00:00:20,530 --> 00:00:19,250 registration issues in particular my 8 00:00:21,760 --> 00:00:20,540 voice is a bit weak today so I'm sorry 9 00:00:24,460 --> 00:00:21,770 I've had a bad call for a couple weeks 10 00:00:26,010 --> 00:00:24,470 hopefully it'll hold out so this is some 11 00:00:30,580 --> 00:00:26,020 work I've been doing with Toni del Genio 12 00:00:31,839 --> 00:00:30,590 for the last few years and I hope it'll 13 00:00:34,389 --> 00:00:31,849 convince you to think a bit more about 14 00:00:36,190 --> 00:00:34,399 Venus as an exoplanet in a sense because 15 00:00:37,480 --> 00:00:36,200 there might be some stuff that we're 16 00:00:39,220 --> 00:00:37,490 missing out there and I hope I can 17 00:00:43,390 --> 00:00:39,230 convince you that this is a possible 18 00:00:45,250 --> 00:00:43,400 scenario anyway amongst many others so 19 00:00:47,410 --> 00:00:45,260 what is the motivation in some sense for 20 00:00:49,540 --> 00:00:47,420 Venus as an exoplanet and only we should 21 00:00:50,680 --> 00:00:49,550 rely only upon Earth's through time as 22 00:00:52,510 --> 00:00:50,690 our only indicator of habitability 23 00:00:55,450 --> 00:00:52,520 that's what we really basically rely on 24 00:00:56,920 --> 00:00:55,460 today for most of our modeling of course 25 00:00:58,870 --> 00:00:56,930 paleo Mars and Paleo Venus may offer 26 00:01:00,910 --> 00:00:58,880 some useful habitats and hey maybe Venus 27 00:01:02,350 --> 00:01:00,920 is simply interesting I mean this is 28 00:01:04,240 --> 00:01:02,360 probably the first conference I've been 29 00:01:06,249 --> 00:01:04,250 to in a long time that wasn't a Venus 30 00:01:09,219 --> 00:01:06,259 conference where Venus was mentioned 31 00:01:11,349 --> 00:01:09,229 more than Mars so I gave you people a 32 00:01:12,789 --> 00:01:11,359 lot of crude kudos for that that's 33 00:01:18,190 --> 00:01:12,799 because it has interesting stuff in its 34 00:01:19,209 --> 00:01:18,200 atmosphere that okay so thankfully and I 35 00:01:21,129 --> 00:01:19,219 knew this before and that Laura was 36 00:01:24,129 --> 00:01:21,139 gonna talk about mag motion so that 37 00:01:25,719 --> 00:01:24,139 makes my life a lot easier but I think 38 00:01:27,809 --> 00:01:25,729 we have to basically scenarios here for 39 00:01:30,010 --> 00:01:27,819 a Venus could evolve through time 40 00:01:31,840 --> 00:01:30,020 well Earth and Venus probably start out 41 00:01:35,139 --> 00:01:31,850 as Laura was talking about and a magma 42 00:01:36,639 --> 00:01:35,149 ocean phase and after a few million 43 00:01:38,889 --> 00:01:36,649 years earth would have cooled down and 44 00:01:41,800 --> 00:01:38,899 had some sort of atmosphere as we know 45 00:01:43,330 --> 00:01:41,810 co2 dominated and n2 dominated the 46 00:01:44,739 --> 00:01:43,340 question is what could have happened to 47 00:01:46,929 --> 00:01:44,749 Venus could have ended up in a scenario 48 00:01:49,330 --> 00:01:46,939 where it also cooled down fairly rapidly 49 00:01:52,330 --> 00:01:49,340 after the magma ocean phase or has it 50 00:01:54,969 --> 00:01:52,340 always been this very dense co2 51 00:01:57,879 --> 00:01:54,979 dominated into 450 degree centigrade 52 00:02:02,349 --> 00:01:57,889 beast for its entire evolutionary 53 00:02:04,719 --> 00:02:02,359 history as I said that longevity of the 54 00:02:06,999 --> 00:02:04,729 magma ocean is crucial as Laura showed 55 00:02:09,749 --> 00:02:07,009 out there have been some very nice work 56 00:02:12,280 --> 00:02:09,759 by cake over mono that that Laura showed 57 00:02:14,590 --> 00:02:12,290 that basically shows that if the planet 58 00:02:16,960 --> 00:02:14,600 magma ocean stays around a bit too long 59 00:02:18,180 --> 00:02:16,970 say order 100 million years you outcast 60 00:02:20,580 --> 00:02:18,190 all of your bolts 61 00:02:22,380 --> 00:02:20,590 and this planet is bone-dry from a start 62 00:02:24,900 --> 00:02:22,390 and that work has been backed up by 63 00:02:26,460 --> 00:02:24,910 others since then if you look carefully 64 00:02:28,860 --> 00:02:26,470 at that mono paper though Venus it's 65 00:02:30,690 --> 00:02:28,870 right at the margins of where they 66 00:02:32,460 --> 00:02:30,700 believe that it will either go one way 67 00:02:34,320 --> 00:02:32,470 or that they'd be type 1 or type 2 so we 68 00:02:37,110 --> 00:02:34,330 actually don't know and we probably will 69 00:02:40,440 --> 00:02:37,120 never know until you people get us some 70 00:02:43,170 --> 00:02:40,450 exoplanet data on really young Venus's 71 00:02:44,910 --> 00:02:43,180 around g2 our stars right in the right 72 00:02:46,949 --> 00:02:44,920 phase and we can make some observations 73 00:02:48,720 --> 00:02:46,959 find out if we see a Venus that's only 74 00:02:51,059 --> 00:02:48,730 200 million years or say 50 million 75 00:02:52,530 --> 00:02:51,069 years old and has no magma ocean that 76 00:02:54,059 --> 00:02:52,540 that could be very interesting for 77 00:02:56,550 --> 00:02:54,069 understanding the evolution of these 78 00:02:59,400 --> 00:02:56,560 Magma's and in particular our own nearby 79 00:03:02,940 --> 00:02:59,410 neighbor so the question is was all the 80 00:03:05,750 --> 00:03:02,950 water lost and is it possible to get 81 00:03:08,180 --> 00:03:05,760 some water back through the late venire 82 00:03:10,380 --> 00:03:08,190 mm because we know that of course Earth 83 00:03:12,860 --> 00:03:10,390 it's Meg motion didn't stay around too 84 00:03:15,449 --> 00:03:12,870 long and there has been some work by 85 00:03:16,770 --> 00:03:15,459 Greenwood and others from 2018 that 86 00:03:18,809 --> 00:03:16,780 states the late veneer could have added 87 00:03:20,820 --> 00:03:18,819 between 5 and 30 percent of Earth's 88 00:03:22,199 --> 00:03:20,830 entire water budget now they're pushing 89 00:03:24,330 --> 00:03:22,209 the envelope of course on those kind of 90 00:03:26,099 --> 00:03:24,340 numbers but imagine if you could get the 91 00:03:29,099 --> 00:03:26,109 same kind of water delivery into Venus 92 00:03:30,660 --> 00:03:29,109 later on even if it lost its magma and 93 00:03:32,880 --> 00:03:30,670 as long as the surface is relatively 94 00:03:35,069 --> 00:03:32,890 cool in the atmosphere it's not crazy 95 00:03:35,819 --> 00:03:35,079 hot it may get a sick it may get a 96 00:03:39,140 --> 00:03:35,829 second chance 97 00:03:41,580 --> 00:03:39,150 actually at being a kind of a thin 98 00:03:42,930 --> 00:03:41,590 veneer of water and having some kind of 99 00:03:46,830 --> 00:03:42,940 the reasonable evolutionary history 100 00:03:49,110 --> 00:03:46,840 comparable to that of Earth okay so then 101 00:03:51,000 --> 00:03:49,120 the question becomes is there really any 102 00:03:54,660 --> 00:03:51,010 evidence for surface liquid water in 103 00:03:56,759 --> 00:03:54,670 Venus is history and if so then clouds 104 00:03:58,860 --> 00:03:56,769 in concert with rotation rate may have 105 00:04:01,080 --> 00:03:58,870 played a key role in Venus's climate 106 00:04:02,449 --> 00:04:01,090 evolution some of that is work that you 107 00:04:06,020 --> 00:04:02,459 all have seen before 108 00:04:08,220 --> 00:04:06,030 so did Venus have surface liquid water 109 00:04:09,210 --> 00:04:08,230 we believe for most of the planet 110 00:04:10,710 --> 00:04:09,220 formation models that they probably 111 00:04:12,690 --> 00:04:10,720 started out with around the same amount 112 00:04:14,520 --> 00:04:12,700 of water as Earth given their similar 113 00:04:17,120 --> 00:04:14,530 masses and given their proximity and the 114 00:04:19,349 --> 00:04:17,130 original disk of our solar system I 115 00:04:20,750 --> 00:04:19,359 mentioned this life and near business 116 00:04:23,250 --> 00:04:20,760 that would have also added some water 117 00:04:25,320 --> 00:04:23,260 the key measurement that we have for 118 00:04:27,210 --> 00:04:25,330 Venus it's really this high d2h ratio 119 00:04:29,190 --> 00:04:27,220 that's about 150 times time terrestrial 120 00:04:31,770 --> 00:04:29,200 they got from the Pioneer Venus mission 121 00:04:33,450 --> 00:04:31,780 way back in the 1970s 122 00:04:36,150 --> 00:04:33,460 the whole problem is that we don't know 123 00:04:37,680 --> 00:04:36,160 the time scale of this water loss we 124 00:04:39,330 --> 00:04:37,690 don't know if this was the original 125 00:04:41,160 --> 00:04:39,340 water with that original steam 126 00:04:44,910 --> 00:04:41,170 atmosphere from the magma ocean days or 127 00:04:46,890 --> 00:04:44,920 was this water lost very rapidly in the 128 00:04:49,080 --> 00:04:46,900 last hundred million years or was itwas 129 00:04:49,440 --> 00:04:49,090 lost very slowly over several billion 130 00:04:51,570 --> 00:04:49,450 years 131 00:04:54,900 --> 00:04:51,580 that's information we can get but which 132 00:04:56,820 --> 00:04:54,910 we did not have today there have been 133 00:04:59,040 --> 00:04:56,830 some other observations from Galileo 134 00:05:01,920 --> 00:04:59,050 NIMS this is a paper from Hashimoto in 135 00:05:04,110 --> 00:05:01,930 2018 who who came up with Vidya that's a 136 00:05:06,210 --> 00:05:04,120 lot of the highlands appear to be 137 00:05:07,680 --> 00:05:06,220 composed of felsic rocks and that could 138 00:05:09,450 --> 00:05:07,690 give us some indications that there's 139 00:05:11,640 --> 00:05:09,460 some granitic material there if you have 140 00:05:13,950 --> 00:05:11,650 been any material you have water at some 141 00:05:16,740 --> 00:05:13,960 point in its history whether everybody 142 00:05:17,160 --> 00:05:16,750 believes in this or not that's that's up 143 00:05:19,940 --> 00:05:17,170 for debate 144 00:05:22,110 --> 00:05:19,950 mmm but it's an it's an interesting idea 145 00:05:25,530 --> 00:05:22,120 then there's also this very interesting 146 00:05:28,440 --> 00:05:25,540 two papers from 1990 and then the work 147 00:05:31,950 --> 00:05:28,450 was done in 2019 as well by by shell nut 148 00:05:34,830 --> 00:05:31,960 that threw some quite modeling dependent 149 00:05:37,200 --> 00:05:34,840 aspects believe that veneer a probe 150 00:05:39,330 --> 00:05:37,210 might have encountered a fragment of a 151 00:05:40,890 --> 00:05:39,340 crust from the original Venus that 152 00:05:43,500 --> 00:05:40,900 presentable to trust your green stone 153 00:05:45,390 --> 00:05:43,510 Bell again very modeling dependent but 154 00:05:47,219 --> 00:05:45,400 very enticing but that's all we have 155 00:05:49,020 --> 00:05:47,229 basically that's the only evidence that 156 00:05:50,550 --> 00:05:49,030 we have that there might have been water 157 00:05:53,159 --> 00:05:50,560 on the surface of Venus at some point 158 00:05:55,140 --> 00:05:53,169 it's not very much I admit means that 159 00:05:58,680 --> 00:05:55,150 where a data star field is what it's 160 00:06:00,560 --> 00:05:58,690 telling you okay if we assume that we 161 00:06:03,390 --> 00:06:00,570 have some water on the surface 162 00:06:04,890 --> 00:06:03,400 let me go back to some really great work 163 00:06:07,500 --> 00:06:04,900 by joonyoung and some other people 164 00:06:08,880 --> 00:06:07,510 people in this room they show there's 165 00:06:10,230 --> 00:06:08,890 this very strong dependence on the inner 166 00:06:12,690 --> 00:06:10,240 edge of the habitable zone on planetary 167 00:06:14,250 --> 00:06:12,700 rotation rate so these are our two 168 00:06:16,290 --> 00:06:14,260 figures that people are using all the 169 00:06:18,510 --> 00:06:16,300 time now and on the x-axis here on the 170 00:06:20,130 --> 00:06:18,520 left you see the incident stellar flux 171 00:06:21,870 --> 00:06:20,140 on the world you can see an early Venus 172 00:06:23,340 --> 00:06:21,880 from about 40 years ago that's the kind 173 00:06:25,500 --> 00:06:23,350 of flux it would have had and even 174 00:06:27,630 --> 00:06:25,510 modern-day Venus and then each one of 175 00:06:31,080 --> 00:06:27,640 these curves is a rotation rate speed so 176 00:06:33,330 --> 00:06:31,090 one is Earth's rotation rate today 16 is 177 00:06:37,230 --> 00:06:33,340 16 times Earth's sidereal rotation rate 178 00:06:38,580 --> 00:06:37,240 64 128 and 256 and the key result from 179 00:06:40,920 --> 00:06:38,590 this paper of course is that this is 180 00:06:43,140 --> 00:06:40,930 kind of dichotomy between slow rotators 181 00:06:45,320 --> 00:06:43,150 and fast rotators so as you amp up your 182 00:06:48,140 --> 00:06:45,330 solar insolation on these worlds 183 00:06:50,450 --> 00:06:48,150 these fast rotators quickly go into a 184 00:06:52,610 --> 00:06:50,460 moister runaway greenhouse de whereas 185 00:06:55,820 --> 00:06:52,620 those slow rotators they heat up much 186 00:06:57,499 --> 00:06:55,830 much more slowly on the right you see 187 00:06:58,939 --> 00:06:57,509 the very similar figure for the same 188 00:07:00,230 --> 00:06:58,949 colors for the same rotation rates and 189 00:07:02,240 --> 00:07:00,240 what you see here is planetary albedo 190 00:07:05,119 --> 00:07:02,250 and the key thing here is you see the 191 00:07:10,219 --> 00:07:05,129 planet Obito is rocketing up on these 192 00:07:11,360 --> 00:07:10,229 slow rotators as I think most of you may 193 00:07:12,980 --> 00:07:11,370 know who knows something about these 194 00:07:15,200 --> 00:07:12,990 papers that's basically because the 195 00:07:17,149 --> 00:07:15,210 planet is slowing down of course the 196 00:07:19,249 --> 00:07:17,159 Hadley cells are increasing in size and 197 00:07:21,350 --> 00:07:19,259 you're getting a large cloud convective 198 00:07:23,089 --> 00:07:21,360 front at the substellar point a very 199 00:07:25,580 --> 00:07:23,099 massive sort of anvil cloud of the 200 00:07:26,959 --> 00:07:25,590 substellar point and that's shown in 201 00:07:29,300 --> 00:07:26,969 this very nice figure from joon-young on 202 00:07:30,589 --> 00:07:29,310 the Left we have a rapid rotator this is 203 00:07:33,230 --> 00:07:30,599 the percentage of clouds and you can see 204 00:07:34,879 --> 00:07:33,240 the cloud is a very banded structure and 205 00:07:37,339 --> 00:07:34,889 on the right you can see for the same 206 00:07:39,559 --> 00:07:37,349 solar insolation a slow rotator hundred 207 00:07:42,350 --> 00:07:39,569 twenty eight sidereal day we have this a 208 00:07:43,700 --> 00:07:42,360 massive cloud clean convective cloud at 209 00:07:45,950 --> 00:07:43,710 the subsolar point and this is what 210 00:07:47,659 --> 00:07:45,960 drives that very high planetary video 211 00:07:49,969 --> 00:07:47,669 and that's what keeps the surface warm 212 00:07:51,230 --> 00:07:49,979 and that's what allows the slow rotators 213 00:07:58,399 --> 00:07:51,240 to move the inner edge of the habitable 214 00:08:00,529 --> 00:07:58,409 zone in quite far okay now I need to ask 215 00:08:01,909 --> 00:08:00,539 you like what do we know about Venus's 216 00:08:04,909 --> 00:08:01,919 rotation and obliquity because I've just 217 00:08:07,100 --> 00:08:04,919 explained to you that if Venus has has 218 00:08:09,110 --> 00:08:07,110 had water it has to have the right 219 00:08:11,570 --> 00:08:09,120 rotation rate for it to have the climate 220 00:08:12,920 --> 00:08:11,580 that is that's possible for having some 221 00:08:15,200 --> 00:08:12,930 kind of habitable conditions so the 222 00:08:16,939 --> 00:08:15,210 question is as the rotation rate evolved 223 00:08:21,019 --> 00:08:16,949 through time and what are the prevailing 224 00:08:22,730 --> 00:08:21,029 theories today so there's a long history 225 00:08:25,219 --> 00:08:22,740 of looking at this stuff I think the 226 00:08:26,779 --> 00:08:25,229 most popular hypothesis is a paper that 227 00:08:28,490 --> 00:08:26,789 actually isn't even a paper it's just a 228 00:08:31,040 --> 00:08:28,500 conference abstract but everybody cites 229 00:08:33,529 --> 00:08:31,050 it like it's it's it's it's the greatest 230 00:08:36,889 --> 00:08:33,539 thing and you read you read popular 231 00:08:39,050 --> 00:08:36,899 science articles or you read even quite 232 00:08:40,819 --> 00:08:39,060 reasonable publications who say Venus's 233 00:08:42,740 --> 00:08:40,829 has the rotation rate and obliquity it 234 00:08:45,050 --> 00:08:42,750 has today because of a of a massive 235 00:08:46,939 --> 00:08:45,060 impactor but nobody's actually done the 236 00:08:48,410 --> 00:08:46,949 dirty work on this we can believe it no 237 00:08:50,000 --> 00:08:48,420 one's done a simulation anything like 238 00:08:52,639 --> 00:08:50,010 the work that random robin canook has 239 00:08:55,400 --> 00:08:52,649 done for our own planet moon it's never 240 00:08:56,960 --> 00:08:55,410 been done nobody's interested so it's 241 00:08:59,250 --> 00:08:56,970 low-hanging fruit for some ambitious 242 00:09:03,640 --> 00:08:59,260 graduate student in this world okay 243 00:09:07,660 --> 00:09:03,650 so we don't know then some earlier work 244 00:09:09,070 --> 00:09:07,670 from the 60 of 60s and 70s looking at 245 00:09:11,800 --> 00:09:09,080 core mental friction and atmosphere 246 00:09:13,420 --> 00:09:11,810 titled torques shown I've shown that 247 00:09:15,340 --> 00:09:13,430 it's possible for the Venus to evolve in 248 00:09:17,350 --> 00:09:15,350 time and also they involves some flips 249 00:09:19,540 --> 00:09:17,360 of the obliquity access basically to 250 00:09:20,800 --> 00:09:19,550 drive it into the state it has and 251 00:09:22,680 --> 00:09:20,810 that's really goes back to this like I 252 00:09:26,050 --> 00:09:22,690 said these papers from Goldman sodor 253 00:09:27,460 --> 00:09:26,060 gold Reich and Pele dobrovolsky and 254 00:09:28,690 --> 00:09:27,470 Ingersoll did the really first heavy 255 00:09:31,360 --> 00:09:28,700 lifting and then Lasker and Correa 256 00:09:34,330 --> 00:09:31,370 basically have done this too in finite 257 00:09:37,330 --> 00:09:34,340 detail since the Senate since 2001 and 258 00:09:39,310 --> 00:09:37,340 Ford one thing that I found really 259 00:09:40,650 --> 00:09:39,320 useful and interesting was this great 260 00:09:43,140 --> 00:09:40,660 paper by Jeremy Lacombe and 261 00:09:45,850 --> 00:09:43,150 collaborators from 2015 that show that 262 00:09:48,340 --> 00:09:45,860 all of these works here assuming that 263 00:09:50,140 --> 00:09:48,350 you have this 90 bar atmosphere and that 264 00:09:51,670 --> 00:09:50,150 is causing the title torque that keeps 265 00:09:55,180 --> 00:09:51,680 it in the retrograde rotation state 266 00:09:56,830 --> 00:09:55,190 basically the idea before was that you 267 00:09:58,420 --> 00:09:56,840 didn't have this super thick atmosphere 268 00:10:00,850 --> 00:09:58,430 the planet would eventually end up in a 269 00:10:02,080 --> 00:10:00,860 tightly lock state but Jeremy showed 270 00:10:04,570 --> 00:10:02,090 through some very nice simulations that 271 00:10:05,620 --> 00:10:04,580 even with a 1 bar atmosphere you can 272 00:10:08,580 --> 00:10:05,630 still end up in a retrograde rotation 273 00:10:11,380 --> 00:10:08,590 state which is really interesting for us 274 00:10:13,570 --> 00:10:11,390 ok so in the meantime we've done it a 275 00:10:15,790 --> 00:10:13,580 couple more simulations looking at solid 276 00:10:17,260 --> 00:10:15,800 body tidal dissipation and possible 277 00:10:18,900 --> 00:10:17,270 ocean cuddle dissipation which I think 278 00:10:21,190 --> 00:10:18,910 you might find interesting 279 00:10:23,110 --> 00:10:21,200 so these are some calculations that I've 280 00:10:25,120 --> 00:10:23,120 done using an equilibrium tide model 281 00:10:27,790 --> 00:10:25,130 developed by Rory Barnes at University 282 00:10:29,080 --> 00:10:27,800 of Washington on the left is a constant 283 00:10:30,460 --> 00:10:29,090 phase lag version of that model and 284 00:10:31,660 --> 00:10:30,470 constant time lag version I'm gonna 285 00:10:33,040 --> 00:10:31,670 constantly I'm gonna focus on the 286 00:10:35,350 --> 00:10:33,050 constant phase lag because it gives me 287 00:10:36,790 --> 00:10:35,360 the answers I want we don't know which 288 00:10:41,980 --> 00:10:36,800 one of these models is correct to be 289 00:10:44,170 --> 00:10:41,990 honest I use a keep win and a love 290 00:10:47,260 --> 00:10:44,180 number two that are values similar to 291 00:10:49,660 --> 00:10:47,270 earth or lack of having any reasonable Q 292 00:10:50,980 --> 00:10:49,670 values for ancient Venus and we have not 293 00:10:52,840 --> 00:10:50,990 really great constraints on either he's 294 00:10:55,480 --> 00:10:52,850 numbers for modern Venus either we just 295 00:10:56,500 --> 00:10:55,490 don't were just a data star field but 296 00:10:59,080 --> 00:10:56,510 the key on the left here is this 297 00:11:00,610 --> 00:10:59,090 constant phase lag model is that if 298 00:11:02,560 --> 00:11:00,620 Venus starts out with a three-day 299 00:11:04,750 --> 00:11:02,570 rotation period in this model and ends 300 00:11:08,350 --> 00:11:04,760 up synchronous 3 Earth Day rotation ends 301 00:11:10,450 --> 00:11:08,360 up synchronous in 684 million years if 302 00:11:12,030 --> 00:11:10,460 it starts out with a 15-day rotation 303 00:11:14,670 --> 00:11:12,040 period it go 304 00:11:17,040 --> 00:11:14,680 synchronous in 132 million years so the 305 00:11:19,650 --> 00:11:17,050 solid-body tides on Venus will slow this 306 00:11:22,530 --> 00:11:19,660 planet down fairly rapidly depending on 307 00:11:24,629 --> 00:11:22,540 what its initial rotation rate was this 308 00:11:26,490 --> 00:11:24,639 is context this is nice paper from Rory 309 00:11:29,819 --> 00:11:26,500 Barnes in 2018 where he uses the same 310 00:11:31,499 --> 00:11:29,829 model he assumes that if earth had not 311 00:11:33,720 --> 00:11:31,509 been hit by the moon and had started out 312 00:11:37,290 --> 00:11:33,730 with a three-day rotation period it 313 00:11:39,090 --> 00:11:37,300 would have gone synchronous about now so 314 00:11:40,710 --> 00:11:39,100 if we had had the moon impact earth 315 00:11:42,269 --> 00:11:40,720 would be approaching a title lock state 316 00:11:44,040 --> 00:11:42,279 as we speak which would be kind of 317 00:11:45,809 --> 00:11:44,050 interesting because we always have this 318 00:11:47,610 --> 00:11:45,819 idea when we do our modeling of 319 00:11:50,220 --> 00:11:47,620 exoplanets that all these planets have 320 00:11:51,780 --> 00:11:50,230 the same spin state as Earth right when 321 00:11:56,939 --> 00:11:51,790 they're out at Earth's orbit that may 322 00:11:58,769 --> 00:11:56,949 not be a very good assumption okay this 323 00:12:01,290 --> 00:11:58,779 is another paper that I've been working 324 00:12:04,620 --> 00:12:01,300 on with Matthias green at the school of 325 00:12:05,160 --> 00:12:04,630 ocean sciences in Bangor Wales and Rory 326 00:12:08,100 --> 00:12:05,170 Barnes 327 00:12:09,809 --> 00:12:08,110 mm-hmm a bit more speculative but the 328 00:12:11,430 --> 00:12:09,819 idea here is to use a numerical ocean 329 00:12:14,220 --> 00:12:11,440 type model that is very commonly used in 330 00:12:17,040 --> 00:12:14,230 the ocean sciences community we took a 331 00:12:19,500 --> 00:12:17,050 modern venous topography with a with two 332 00:12:21,120 --> 00:12:19,510 different kinds of depth ocean we did a 333 00:12:22,860 --> 00:12:21,130 whole suite of simulation using 334 00:12:26,790 --> 00:12:22,870 rotational periods from what Venus is 335 00:12:29,670 --> 00:12:26,800 today - 23 - pro-grade plus 64 sidereal 336 00:12:32,579 --> 00:12:29,680 day and the title dissipation just from 337 00:12:34,019 --> 00:12:32,589 the ocean varies by five orders of 338 00:12:35,519 --> 00:12:34,029 magnitude depending on where you are in 339 00:12:38,430 --> 00:12:35,529 this parameter space and the maximum 340 00:12:41,660 --> 00:12:38,440 slowdown for this model is that it will 341 00:12:43,980 --> 00:12:41,670 slow down by 72 days per million years 342 00:12:46,829 --> 00:12:43,990 so total dissipation from a shallow 343 00:12:48,120 --> 00:12:46,839 ocean on Venus is extremely efficient at 344 00:12:49,410 --> 00:12:48,130 slowing down the rotation rate of this 345 00:12:50,879 --> 00:12:49,420 world another thing we should be 346 00:12:54,059 --> 00:12:50,889 thinking about when we think about 347 00:12:55,530 --> 00:12:54,069 rotation rates of exoplanets should this 348 00:12:57,689 --> 00:12:55,540 be surprising I don't I'm not so sure 349 00:12:59,670 --> 00:12:57,699 because on earth we already know that 350 00:13:01,379 --> 00:12:59,680 the total love for the subtle earth is 351 00:13:03,360 --> 00:13:01,389 much lower than the total love for the 352 00:13:04,439 --> 00:13:03,370 ocean so we already know that the oceans 353 00:13:06,000 --> 00:13:04,449 are dissipating are much more 354 00:13:08,939 --> 00:13:06,010 dissipative on earth and the solid-body 355 00:13:10,110 --> 00:13:08,949 torques are so that shouldn't be so 356 00:13:12,210 --> 00:13:10,120 surprising although some of my friends 357 00:13:15,470 --> 00:13:12,220 who work in dynamics were surprised by 358 00:13:19,160 --> 00:13:17,750 okay so now that I've giving you all 359 00:13:20,510 --> 00:13:19,170 that and I'm gonna make these 360 00:13:22,430 --> 00:13:20,520 assumptions that the planet has been 361 00:13:26,450 --> 00:13:22,440 slit has been spinning slowly for most 362 00:13:28,550 --> 00:13:26,460 of its history and it had some kind of 363 00:13:31,340 --> 00:13:28,560 atmosphere early on and it's gonna show 364 00:13:34,400 --> 00:13:31,350 you some some fairly simple simulation 365 00:13:37,160 --> 00:13:34,410 so this is using our rocky 3d general 366 00:13:38,240 --> 00:13:37,170 circulation model and I'm just going to 367 00:13:39,800 --> 00:13:38,250 talk quickly about a couple different 368 00:13:42,230 --> 00:13:39,810 atmospheres of tried so we went back to 369 00:13:44,410 --> 00:13:42,240 4.2 giga years ago when the insulation 370 00:13:47,330 --> 00:13:44,420 that Venus was receiving was about 40% 371 00:13:50,660 --> 00:13:47,340 what earth receives today and I gave it 372 00:13:52,520 --> 00:13:50,670 a hundred percent co2 atmosphere because 373 00:13:53,960 --> 00:13:52,530 there are some models that show that 374 00:13:55,400 --> 00:13:53,970 early Earth's atmosphere could have been 375 00:13:57,350 --> 00:13:55,410 very I mean very early Earth's 376 00:13:59,420 --> 00:13:57,360 atmosphere could have been a pure co2 377 00:14:01,850 --> 00:13:59,430 atmosphere before the nitrogen started 378 00:14:03,050 --> 00:14:01,860 getting out mixing things up then we 379 00:14:04,310 --> 00:14:03,060 have another simulation a set of 380 00:14:06,590 --> 00:14:04,320 simulations at point seventy eighty 381 00:14:09,350 --> 00:14:06,600 years ago where we're receiving about 382 00:14:11,000 --> 00:14:09,360 70% more rated incidents flux than the 383 00:14:13,520 --> 00:14:11,010 nurse receiving we use a very modern 384 00:14:14,720 --> 00:14:13,530 earth composition in that sense assuming 385 00:14:15,980 --> 00:14:14,730 that some kind of carbon and silicate 386 00:14:17,510 --> 00:14:15,990 cycle would have taken place in the 387 00:14:19,400 --> 00:14:17,520 planet carbon would have been drawn down 388 00:14:22,550 --> 00:14:19,410 nitrogen would have gone up and other 389 00:14:24,590 --> 00:14:22,560 species would have been produced and 390 00:14:27,050 --> 00:14:24,600 then given the fact that Venus is 391 00:14:28,580 --> 00:14:27,060 topography from four billion years ago 392 00:14:30,770 --> 00:14:28,590 or 1 billion years ago it's completely 393 00:14:33,530 --> 00:14:30,780 unknown because the surface of Venus is 394 00:14:34,640 --> 00:14:33,540 is is one of the youngest surfaces in 395 00:14:36,350 --> 00:14:34,650 the solar system it's less than a 396 00:14:38,120 --> 00:14:36,360 billion years old we know that from 397 00:14:39,800 --> 00:14:38,130 crater counts I tried a whole slew of 398 00:14:41,480 --> 00:14:39,810 different we try to whole slew of 399 00:14:43,880 --> 00:14:41,490 different topography so the first one we 400 00:14:46,250 --> 00:14:43,890 did using the first we are using modern 401 00:14:47,240 --> 00:14:46,260 Venus topography in lieu of using 402 00:14:49,730 --> 00:14:47,250 anything else because there's sort of 403 00:14:51,530 --> 00:14:49,740 the least worst choice that we have the 404 00:14:53,870 --> 00:14:51,540 first one is an Ave type dune world 405 00:14:55,940 --> 00:14:53,880 where we only put twenty centimeters of 406 00:14:58,960 --> 00:14:55,950 water in the soil so that limits the 407 00:15:01,280 --> 00:14:58,970 amount of h2o into the atmosphere and 408 00:15:02,990 --> 00:15:01,290 basically eight h2o is an efficient 409 00:15:05,180 --> 00:15:03,000 greenhouse gases as Lara showed us with 410 00:15:06,470 --> 00:15:05,190 some of her stuff earlier then we have 411 00:15:08,930 --> 00:15:06,480 another simulation we put ten meter 412 00:15:10,400 --> 00:15:08,940 water equivalent layer and lakes in the 413 00:15:12,320 --> 00:15:10,410 lowest lying regions of the planet we 414 00:15:14,390 --> 00:15:12,330 let the planet evolve in time and we as 415 00:15:16,640 --> 00:15:14,400 a model decide where the water should 416 00:15:18,410 --> 00:15:16,650 actually go so it will do a calculation 417 00:15:20,630 --> 00:15:18,420 based on evaporation versus 418 00:15:21,980 --> 00:15:20,640 precipitation versus runoff and it 419 00:15:23,120 --> 00:15:21,990 distributes the model model quite 420 00:15:25,850 --> 00:15:23,130 differently than what you would expect 421 00:15:27,230 --> 00:15:25,860 from your initial conditions and the 422 00:15:29,360 --> 00:15:27,240 third one was a three ten meter deep 423 00:15:31,340 --> 00:15:29,370 ocean basically we use in our 424 00:15:33,410 --> 00:15:31,350 sixteen paper again using modern Venus 425 00:15:35,360 --> 00:15:33,420 topography and then because everyone 426 00:15:37,070 --> 00:15:35,370 uses modern modern earth topography we 427 00:15:39,110 --> 00:15:37,080 also did that for fun of course it never 428 00:15:40,519 --> 00:15:39,120 had modern orthography but we just use 429 00:15:42,890 --> 00:15:40,529 it for a different kind of topography 430 00:15:46,610 --> 00:15:42,900 with a three ten meter deep bathtub 431 00:15:48,560 --> 00:15:46,620 ocean we use these kind of depths of the 432 00:15:50,450 --> 00:15:48,570 ocean because the DTH ratio estimate 433 00:15:52,940 --> 00:15:50,460 does give us a very broad window the 434 00:15:54,800 --> 00:15:52,950 driver trucks through from the donahue 435 00:15:56,030 --> 00:15:54,810 and russell papers from the 80s they 436 00:15:59,750 --> 00:15:56,040 basically said that venus could have had 437 00:16:01,550 --> 00:15:59,760 anywhere between five and 550 meters of 438 00:16:03,230 --> 00:16:01,560 water water equivalent across the 439 00:16:05,660 --> 00:16:03,240 surface so that's why we have a lot of 440 00:16:06,800 --> 00:16:05,670 room to play with here and because aqua 441 00:16:08,840 --> 00:16:06,810 planets are very popular in this 442 00:16:12,410 --> 00:16:08,850 community we also did an aqua ponic just 443 00:16:14,000 --> 00:16:12,420 for fun so instead of showing you lots 444 00:16:16,460 --> 00:16:14,010 of plots with lots of lines and lots of 445 00:16:19,850 --> 00:16:16,470 points i've been inspired by calling 446 00:16:21,290 --> 00:16:19,860 Goldblatt's talk back in CC t p3 so you 447 00:16:23,300 --> 00:16:21,300 can crucify him if you don't like my 448 00:16:25,130 --> 00:16:23,310 cartoon drawing of what i'm about to 449 00:16:28,010 --> 00:16:25,140 show you so this is all of the 450 00:16:30,320 --> 00:16:28,020 simulations and a really fancy cartoon i 451 00:16:34,100 --> 00:16:30,330 would call it in a sense so what you see 452 00:16:35,510 --> 00:16:34,110 on the left here is the temperature of 453 00:16:38,240 --> 00:16:35,520 the world and then on the bottom axis 454 00:16:40,730 --> 00:16:38,250 you see a timeline from 4 Giga years ago 455 00:16:42,920 --> 00:16:40,740 where the insulation was 40% more than 456 00:16:45,829 --> 00:16:42,930 present-day earth 70 % and even i did 457 00:16:48,530 --> 00:16:45,839 some simulations today what happens here 458 00:16:50,920 --> 00:16:48,540 is still completely unknown and can stun 459 00:16:53,570 --> 00:16:50,930 constrained as Laura said we don't know 460 00:16:55,160 --> 00:16:53,580 how fast this planet cooled down we 461 00:16:56,630 --> 00:16:55,170 don't know the timescale we don't know 462 00:16:59,480 --> 00:16:56,640 what the atmosphere was even made of but 463 00:17:01,040 --> 00:16:59,490 I'm gonna assume because of the ideas of 464 00:17:02,930 --> 00:17:01,050 using compared to climatology they 465 00:17:04,910 --> 00:17:02,940 probably had a co2 down eight atmosphere 466 00:17:07,549 --> 00:17:04,920 if you take all those topographies I 467 00:17:09,470 --> 00:17:07,559 used for co2 dominated atmospheres the 468 00:17:11,960 --> 00:17:09,480 temperature ranges for any of those 469 00:17:13,520 --> 00:17:11,970 topographies even at a co2 dominated 470 00:17:15,679 --> 00:17:13,530 atmosphere because of the slow rotation 471 00:17:18,740 --> 00:17:15,689 of the world and the effects the clouds 472 00:17:20,090 --> 00:17:18,750 have on their planetary albedo I get a 473 00:17:24,679 --> 00:17:20,100 range of temperatures from somewhere 474 00:17:27,110 --> 00:17:24,689 around 30 to 50 degrees centigrade so 475 00:17:29,900 --> 00:17:27,120 it's not it's not a it's not a crazy 476 00:17:31,669 --> 00:17:29,910 world the stratosphere and some of these 477 00:17:33,710 --> 00:17:31,679 models does have a lot of water vapour 478 00:17:35,600 --> 00:17:33,720 in it which means the plan is going to 479 00:17:38,300 --> 00:17:35,610 lose what ocean it has over some time 480 00:17:39,440 --> 00:17:38,310 scale which we haven't calculated and 481 00:17:40,610 --> 00:17:39,450 then the idea again as I said is that 482 00:17:42,110 --> 00:17:40,620 there would be some kind of carbon in 483 00:17:43,280 --> 00:17:42,120 silicates cycle of course it won't be 484 00:17:44,720 --> 00:17:43,290 linear like this 485 00:17:46,460 --> 00:17:44,730 it'll go up and down and all kinds of 486 00:17:48,110 --> 00:17:46,470 things will happen but the last 487 00:17:51,140 --> 00:17:48,120 simulation or one of the last emulation 488 00:17:54,230 --> 00:17:51,150 she did was at 0.7 0.0 0.7 giggy years 489 00:17:56,870 --> 00:17:54,240 ago again with that into co2 dominate 490 00:17:57,800 --> 00:17:56,880 atmosphere and you get temperatures that 491 00:18:01,070 --> 00:17:57,810 are quite a bit lower 492 00:18:02,450 --> 00:18:01,080 they're basically between 15 and 30 493 00:18:05,390 --> 00:18:02,460 degrees centigrade no matter what your 494 00:18:07,040 --> 00:18:05,400 topography is now why did I kind of stop 495 00:18:08,630 --> 00:18:07,050 there because the surface is completely 496 00:18:10,700 --> 00:18:08,640 new to us we don't know what happened 497 00:18:13,520 --> 00:18:10,710 but the idea in this model would be that 498 00:18:15,200 --> 00:18:13,530 the planet evolved in time and that what 499 00:18:16,910 --> 00:18:15,210 drove the planet into its present-day 500 00:18:19,280 --> 00:18:16,920 state was some kind of major overturning 501 00:18:21,020 --> 00:18:19,290 event the results of which we see on the 502 00:18:23,240 --> 00:18:21,030 surface today that very new surface we 503 00:18:25,070 --> 00:18:23,250 see on Venus and that's what drove the 504 00:18:27,410 --> 00:18:25,080 planet into its present state where the 505 00:18:29,240 --> 00:18:27,420 co2 was released from the carbonate that 506 00:18:31,790 --> 00:18:29,250 were locked up on the surface into the 507 00:18:33,890 --> 00:18:31,800 atmosphere over a fairly short timescale 508 00:18:35,720 --> 00:18:33,900 say hundreds of millions of years it 509 00:18:36,830 --> 00:18:35,730 will not be a catastrophic resurfacing I 510 00:18:38,750 --> 00:18:36,840 think that's pretty much agreed in the 511 00:18:39,920 --> 00:18:38,760 Venus community now it's not like it's 512 00:18:41,660 --> 00:18:39,930 overturn event and the resurfacing 513 00:18:43,430 --> 00:18:41,670 happened like in the blink of an eye 514 00:18:44,540 --> 00:18:43,440 geologically which is 50 hundred million 515 00:18:47,000 --> 00:18:44,550 years we're talking about hundreds of 516 00:18:48,650 --> 00:18:47,010 millions of years but that would drive 517 00:18:51,650 --> 00:18:48,660 to pun it into the into the current 518 00:18:53,180 --> 00:18:51,660 runaway greenhouse date but we did do 519 00:18:54,860 --> 00:18:53,190 one more simulate a set of simulations 520 00:18:57,080 --> 00:18:54,870 again where we kept this set of modern 521 00:19:02,300 --> 00:18:57,090 day earth and to dominate atmosphere and 522 00:19:03,530 --> 00:19:02,310 even today at one point 999 time one 523 00:19:05,450 --> 00:19:03,540 point nine times what earth receives 524 00:19:07,190 --> 00:19:05,460 today in terms of solar insolation the 525 00:19:08,240 --> 00:19:07,200 temperature the atmosphere for any of 526 00:19:10,220 --> 00:19:08,250 these simulations didn't change very 527 00:19:11,600 --> 00:19:10,230 much and that corresponds actually to a 528 00:19:13,880 --> 00:19:11,610 couple of simulations that joonyoung 529 00:19:18,890 --> 00:19:13,890 actually did in this 2014 paper that 530 00:19:21,050 --> 00:19:18,900 don't get a lot of press so I think this 531 00:19:23,720 --> 00:19:21,060 fits kind of nicely in with an old paper 532 00:19:26,420 --> 00:19:23,730 that I really like from John Valle from 533 00:19:27,490 --> 00:19:26,430 2002 the papers titled a cool early 534 00:19:30,050 --> 00:19:27,500 Earth 535 00:19:33,380 --> 00:19:30,060 now John plots has access the other way 536 00:19:35,570 --> 00:19:33,390 so again I I took Liberty and redrew his 537 00:19:37,730 --> 00:19:35,580 plot for you so on the Left axis you see 538 00:19:39,830 --> 00:19:37,740 impact rate there's some kind of 539 00:19:42,470 --> 00:19:39,840 planetary accretion here and the planets 540 00:19:44,180 --> 00:19:42,480 he does a very nice job of looking at 541 00:19:47,030 --> 00:19:44,190 zircon ages he's gone all the way back 542 00:19:49,250 --> 00:19:47,040 to 4.3 Giga years ago now in his 2014 543 00:19:51,800 --> 00:19:49,260 paper to show that Earth probably had 544 00:19:54,920 --> 00:19:51,810 this cool period very early on in its 545 00:19:56,420 --> 00:19:54,930 history back then there were a lot more 546 00:19:57,200 --> 00:19:56,430 proponents I would say in the community 547 00:19:59,570 --> 00:19:57,210 for the LH 548 00:20:01,909 --> 00:19:59,580 but I think that a lot of that that 549 00:20:06,080 --> 00:20:01,919 enthusiasm has gone by the wayside in 550 00:20:08,029 --> 00:20:06,090 recent years but if this is true 551 00:20:09,919 --> 00:20:08,039 these zircon measurements by Valley and 552 00:20:11,870 --> 00:20:09,929 many others we probably certainly had 553 00:20:13,909 --> 00:20:11,880 most surface temperatures we had liquid 554 00:20:15,680 --> 00:20:13,919 water we have continental crust that's 555 00:20:17,000 --> 00:20:15,690 that's work that's also been supported 556 00:20:20,180 --> 00:20:17,010 by a couple of really nice papers by 557 00:20:24,019 --> 00:20:20,190 Corey Naga and collaborators and just 558 00:20:26,630 --> 00:20:24,029 yesterday I saw this paper by Moses and 559 00:20:28,789 --> 00:20:26,640 brass er who were at Colorado and lcn 560 00:20:29,960 --> 00:20:28,799 collaborators that say that show 561 00:20:31,760 --> 00:20:29,970 basically the same thing they have some 562 00:20:33,289 --> 00:20:31,770 very beautiful plots in there and their 563 00:20:35,659 --> 00:20:33,299 paper that show almost the same thing as 564 00:20:36,980 --> 00:20:35,669 valley has here but without the LHB 565 00:20:39,220 --> 00:20:36,990 because they are not good performance to 566 00:20:41,539 --> 00:20:39,230 the LHB the let you have a bombardment 567 00:20:42,889 --> 00:20:41,549 so this kind of fits nicely into that 568 00:20:45,260 --> 00:20:42,899 picture I showed you for Venus if the 569 00:20:47,180 --> 00:20:45,270 planet can cool down early then you end 570 00:20:49,730 --> 00:20:47,190 up in this very cool early phase pretty 571 00:20:53,480 --> 00:20:49,740 easily again depending on rotation rate 572 00:20:55,430 --> 00:20:53,490 for Venus and and that it has surface 573 00:20:56,870 --> 00:20:55,440 liquid water for Earth we don't have 574 00:20:58,100 --> 00:20:56,880 that problem but in the interest of 575 00:21:01,720 --> 00:20:58,110 compared to comet ology I thought this 576 00:21:05,570 --> 00:21:01,730 was a really interesting picture to see 577 00:21:07,190 --> 00:21:05,580 okay so I would also like to talk about 578 00:21:09,169 --> 00:21:07,200 this in the tents of the the Kane zone 579 00:21:11,299 --> 00:21:09,179 I'm sorry I meant that the Venus zone 580 00:21:13,330 --> 00:21:11,309 that's a reminder for you guys to all go 581 00:21:15,950 --> 00:21:13,340 look at Steven Kane's poster tomorrow on 582 00:21:19,639 --> 00:21:15,960 Venus as an exoplanet or ex planetary 583 00:21:20,810 --> 00:21:19,649 laboratory so idea here is that we have 584 00:21:22,159 --> 00:21:20,820 that this Venus own which people 585 00:21:24,649 --> 00:21:22,169 basically have been ignoring for years 586 00:21:25,970 --> 00:21:24,659 and in terms of the habitable zone and I 587 00:21:28,610 --> 00:21:25,980 once it I want to promote the idea of 588 00:21:30,409 --> 00:21:28,620 what I call the optimistic Venus zone we 589 00:21:32,060 --> 00:21:30,419 always think these ridiculous labels for 590 00:21:33,470 --> 00:21:32,070 things optimistic habitable zone you 591 00:21:35,659 --> 00:21:33,480 know pessimistic habitable zone 592 00:21:36,440 --> 00:21:35,669 conservative habitable zone pretty thing 593 00:21:38,570 --> 00:21:36,450 we're gonna have like the Trump 594 00:21:41,120 --> 00:21:38,580 habitable zone but I want to stick with 595 00:21:42,200 --> 00:21:41,130 the optimistic Venus zone it's what I 596 00:21:43,940 --> 00:21:42,210 want to promote to you and that we 597 00:21:46,220 --> 00:21:43,950 shouldn't discount all of these these 598 00:21:48,039 --> 00:21:46,230 worlds sitting in here we have to know 599 00:21:50,299 --> 00:21:48,049 the rotation rates of these planets 600 00:21:52,190 --> 00:21:50,309 before we really go looking at them and 601 00:21:53,720 --> 00:21:52,200 maybe more ten to twenty years away from 602 00:21:56,899 --> 00:21:53,730 from doing that depends on who you talk 603 00:21:58,070 --> 00:21:56,909 to and what they think our next 604 00:21:59,990 --> 00:21:58,080 generation of telescopes going to be 605 00:22:01,850 --> 00:22:00,000 capable of but we shouldn't discard all 606 00:22:03,500 --> 00:22:01,860 these just like we shouldn't discard our 607 00:22:05,360 --> 00:22:03,510 nearest neighbor which is completely 608 00:22:07,010 --> 00:22:05,370 neglected by the planetary science 609 00:22:09,019 --> 00:22:07,020 community for the most part I mean Mars 610 00:22:10,960 --> 00:22:09,029 gets a mission every 18 months or or 611 00:22:13,060 --> 00:22:10,970 more and Venus gets in 612 00:22:14,860 --> 00:22:13,070 maybe every 10 years if it's lucky we 613 00:22:18,250 --> 00:22:14,870 haven't had an institution mission to 614 00:22:19,240 --> 00:22:18,260 Venus since the 1980s basically that's 615 00:22:21,549 --> 00:22:19,250 why we don't know anything about this 616 00:22:22,810 --> 00:22:21,559 appointment and one other thing I want 617 00:22:24,700 --> 00:22:22,820 to show you very quickly that our model 618 00:22:25,990 --> 00:22:24,710 outputs at the very end is some direct 619 00:22:28,330 --> 00:22:26,000 imaging spectrum now there's no noise 620 00:22:29,830 --> 00:22:28,340 model in this or anything but on the 621 00:22:32,020 --> 00:22:29,840 left you can see that co2 dominate 622 00:22:34,029 --> 00:22:32,030 atmosphere is very easy to detect you 623 00:22:35,770 --> 00:22:34,039 have these very large bands co2 bands 624 00:22:37,930 --> 00:22:35,780 that were very easy to detect compared 625 00:22:39,700 --> 00:22:37,940 to the in to dominate atmosphere in 626 00:22:41,380 --> 00:22:39,710 terms of the thermal light that you can 627 00:22:44,049 --> 00:22:41,390 rip detection ones this is from 4 to 20 628 00:22:45,730 --> 00:22:44,059 microns so this kind of thing would be 629 00:22:47,440 --> 00:22:45,740 observable in a fairly even in a fairly 630 00:22:49,750 --> 00:22:47,450 young Venus even a few hundred million 631 00:22:53,500 --> 00:22:49,760 years old if it had this kind of surface 632 00:22:55,169 --> 00:22:53,510 habitable water conditions okay 633 00:22:57,730 --> 00:22:55,179 so I want to try to keep my talk short 634 00:22:59,200 --> 00:22:57,740 so my point is that if a cool early 635 00:23:00,700 --> 00:22:59,210 Venus had surface like what it's not 636 00:23:02,140 --> 00:23:00,710 clear that solar luminosity is the 637 00:23:04,930 --> 00:23:02,150 defining factor in its climate evolution 638 00:23:06,520 --> 00:23:04,940 why do I say that because I read things 639 00:23:08,560 --> 00:23:06,530 in the popular press about this all the 640 00:23:10,899 --> 00:23:08,570 time Venus had liquid oceans and if the 641 00:23:12,399 --> 00:23:10,909 Sun got warmer and warmer the oceans 642 00:23:14,680 --> 00:23:12,409 boiled off and then it was the end of 643 00:23:17,470 --> 00:23:14,690 the world our models do not ship it in 644 00:23:18,880 --> 00:23:17,480 any any way at all and and this guy is 645 00:23:20,260 --> 00:23:18,890 one of the guys to blame for it Paul 646 00:23:21,399 --> 00:23:20,270 Sutter at Ohio State here it is but as 647 00:23:22,990 --> 00:23:21,409 the Sun age that half of those own 648 00:23:24,010 --> 00:23:23,000 steadily moved outward and as Venus 649 00:23:26,500 --> 00:23:24,020 approached the inner edge of the zone 650 00:23:28,000 --> 00:23:26,510 things started to go haywire doesn't 651 00:23:33,669 --> 00:23:28,010 work in school okay 652 00:23:35,230 --> 00:23:33,679 anyway optimistic Venus zone exoplanet 653 00:23:36,490 --> 00:23:35,240 habitability essence require rotation 654 00:23:38,680 --> 00:23:36,500 rate knowledge I think I think it's do 655 00:23:40,930 --> 00:23:38,690 we need Venus in situ observations to 656 00:23:42,880 --> 00:23:40,940 Khmers geologic and volatile history 657 00:23:45,340 --> 00:23:42,890 that means all these beautiful noble 658 00:23:47,440 --> 00:23:45,350 gases and all of their isotopes it's the 659 00:23:49,779 --> 00:23:47,450 only way we're gonna know if this planet 660 00:23:51,490 --> 00:23:49,789 ever had liquid water in its surface and 661 00:23:54,159 --> 00:23:51,500 when it lost that water and how it lost 662 00:23:55,659 --> 00:23:54,169 that water no mapping mission nothing 663 00:23:57,399 --> 00:23:55,669 from orbits ever gonna tell us any of 664 00:23:58,690 --> 00:23:57,409 that so dude ever tells you I want to do 665 00:23:59,919 --> 00:23:58,700 an orbital mission for Venus it's gonna 666 00:24:03,220 --> 00:23:59,929 be so great we're gonna get all this you 667 00:24:05,500 --> 00:24:03,230 can tell them no we need noble gas 668 00:24:07,080 --> 00:24:05,510 abundances and so for this for this 669 00:24:09,640 --> 00:24:07,090 reason I give the Russians great credit 670 00:24:12,060 --> 00:24:09,650 they're really trying hard to redo the 671 00:24:15,460 --> 00:24:12,070 the Vega missions but kind of amped up 672 00:24:17,830 --> 00:24:15,470 once more to do one more mission to the 673 00:24:20,020 --> 00:24:17,840 surface some of us are going to Moscow 674 00:24:23,409 --> 00:24:20,030 next month to do some landing site 675 00:24:24,490 --> 00:24:23,419 selection and hope the NASA will pony up 676 00:24:25,840 --> 00:24:24,500 some money it is to put 677 00:24:27,790 --> 00:24:25,850 balloon instrument on this mission and 678 00:24:29,920 --> 00:24:27,800 get us these noble gas instruments 679 00:24:33,010 --> 00:24:29,930 Institute on the surface from that 680 00:24:34,660 --> 00:24:33,020 Russian spacecraft the question is will 681 00:24:36,730 --> 00:24:34,670 Venus is history constrained possible 682 00:24:37,900 --> 00:24:36,740 exoplanetary climates don't know it 683 00:24:39,520 --> 00:24:37,910 depends if we go back to the surface of 684 00:24:40,900 --> 00:24:39,530 Venus and otherwise if you're gonna tell 685 00:24:42,190 --> 00:24:40,910 us everything about Venus cuz we ain't 686 00:24:43,900 --> 00:24:42,200 gonna know our nearest neighbor is 687 00:24:45,850 --> 00:24:43,910 gonna be sittin there waiting for us to 688 00:24:56,770 --> 00:24:45,860 make some it anyway thank you very much 689 00:24:57,970 --> 00:24:56,780 I'm so glad my voice fell down we have 690 00:25:04,840 --> 00:24:57,980 time for questions 691 00:25:09,700 --> 00:25:07,450 Edwin kite University of Chicago what's 692 00:25:12,820 --> 00:25:09,710 observation either from liberal gases or 693 00:25:15,310 --> 00:25:12,830 other sources were disproved the early 694 00:25:17,500 --> 00:25:15,320 habitable fetus hypothesis what would 695 00:25:18,700 --> 00:25:17,510 disprove it well if we did find out that 696 00:25:21,820 --> 00:25:18,710 it lost all of its water in the first 697 00:25:24,010 --> 00:25:21,830 hundred million years that the noble 698 00:25:24,340 --> 00:25:24,020 gases will tell us that that's all we 699 00:25:31,000 --> 00:25:24,350 need 700 00:25:34,060 --> 00:25:31,010 I hate that was a excellent talk thank 701 00:25:36,040 --> 00:25:34,070 you a lot of the work that shows the 702 00:25:37,480 --> 00:25:36,050 dependence of the state of the 703 00:25:38,860 --> 00:25:37,490 sensitivity of the climate of the 704 00:25:41,110 --> 00:25:38,870 rotation rate will depend on cloud 705 00:25:43,360 --> 00:25:41,120 feedback parameters so as any of the 706 00:25:46,060 --> 00:25:43,370 uncertainty of that or maybe convection 707 00:25:48,220 --> 00:25:46,070 scale modeling being looked at not in 708 00:25:51,100 --> 00:25:48,230 not in detail no but it has been seen in 709 00:25:52,660 --> 00:25:51,110 three different GCMs that have coated up 710 00:25:54,760 --> 00:25:52,670 their cloud convection schemes in 711 00:25:59,280 --> 00:25:54,770 completely different ways so that's all 712 00:26:02,500 --> 00:25:59,290 I can say on that I was encouraged by 713 00:26:04,600 --> 00:26:02,510 awareness II was his talk I was anyway I 714 00:26:06,070 --> 00:26:04,610 was too conversed by this by this by by 715 00:26:08,050 --> 00:26:06,080 Dennis's talk sorry by Dennis's talk 716 00:26:10,150 --> 00:26:08,060 yesterday that showed this very detailed 717 00:26:12,760 --> 00:26:10,160 of cloud resolving model in its 718 00:26:14,080 --> 00:26:12,770 comparison to the GCM if I don't think 719 00:26:15,370 --> 00:26:14,090 he did it on purpose it was kind of 720 00:26:17,380 --> 00:26:15,380 portrayed like a GCM doesn't do a very 721 00:26:18,490 --> 00:26:17,390 good job but I actually think the GCM 722 00:26:20,350 --> 00:26:18,500 did a very good job if you look at his 723 00:26:22,450 --> 00:26:20,360 figures very carefully it mimics very 724 00:26:24,250 --> 00:26:22,460 nicely with the cloud resolving model 725 00:26:26,680 --> 00:26:24,260 legs are actually doing so I think the 726 00:26:28,600 --> 00:26:26,690 GCMs are doing a quiet good job we have 727 00:26:30,370 --> 00:26:28,610 also completely rewritten our claude 728 00:26:32,500 --> 00:26:30,380 convection scheme for our next version 729 00:26:33,940 --> 00:26:32,510 of the model but the earth climate model 730 00:26:35,680 --> 00:26:33,950 it's going to come out next year and 731 00:26:37,270 --> 00:26:35,690 we're going to release the planetary 732 00:26:38,289 --> 00:26:37,280 version of that it's one of the first 733 00:26:43,799 --> 00:26:38,299 things we're gonna chest out 734 00:26:54,430 --> 00:26:52,599 you methods obey from a Geneva 735 00:26:56,259 --> 00:26:54,440 Observatory I would like to know if you 736 00:26:58,509 --> 00:26:56,269 explore whether this crowd feedback 737 00:27:01,419 --> 00:26:58,519 could also work if the background 738 00:27:03,129 --> 00:27:01,429 pressure was ire and if they were like a 739 00:27:04,959 --> 00:27:03,139 freak suit atmosphere is it something 740 00:27:08,589 --> 00:27:04,969 that could be robust to thicker 741 00:27:11,049 --> 00:27:08,599 atmosphere I think it is I've only done 742 00:27:12,190 --> 00:27:11,059 a couple bars Co to my goal is to do up 743 00:27:14,469 --> 00:27:12,200 to ten bars because we have the 744 00:27:15,819 --> 00:27:14,479 radiation tables for that and I just 745 00:27:17,259 --> 00:27:15,829 haven't gotten around to it but I think 746 00:27:20,049 --> 00:27:17,269 it's a really great idea I mean I 747 00:27:22,149 --> 00:27:20,059 actually I put a proposal and recently 748 00:27:23,889 --> 00:27:22,159 to one of the Roses programs to work 749 00:27:26,379 --> 00:27:23,899 with Roxanna lucu who some of whose data 750 00:27:28,060 --> 00:27:26,389 Lara showed and Mark Marley and Kevin's 751 00:27:30,729 --> 00:27:28,070 on Lee and Stephen canes in that 752 00:27:32,859 --> 00:27:30,739 proposal to to really redo some of those 753 00:27:34,810 --> 00:27:32,869 tamaño models and loop whose models 754 00:27:36,879 --> 00:27:34,820 early on but put clouds and actually 755 00:27:38,279 --> 00:27:36,889 didn't have clouds in those models so we 756 00:27:41,799 --> 00:27:38,289 are going to put clouds in and then 757 00:27:44,289 --> 00:27:41,809 bring those models down from say you 758 00:27:46,269 --> 00:27:44,299 know thousand bar atmospheres whatever 759 00:27:48,549 --> 00:27:46,279 you want very high temperatures and then 760 00:27:50,769 --> 00:27:48,559 down to where my model can meet them say 761 00:27:52,749 --> 00:27:50,779 at ten thirty forty bars because their 762 00:27:54,519 --> 00:27:52,759 models are all you know much lower 763 00:27:56,019 --> 00:27:54,529 dimensionally models obviously and then 764 00:27:58,119 --> 00:27:56,029 see what we can see if we can if we can 765 00:28:00,399 --> 00:27:58,129 tie up assuming that their models are 766 00:28:01,930 --> 00:28:00,409 giving answers that are useful to our 767 00:28:09,149 --> 00:28:01,940 models inputs basically down the road 768 00:28:16,139 --> 00:28:13,629 you know so I'm going back to one of 769 00:28:19,569 --> 00:28:16,149 castings early papers he remarked that 770 00:28:22,930 --> 00:28:19,579 clouds could would tend to inhibit the 771 00:28:26,739 --> 00:28:22,940 the true runaway greenhouse of in for 772 00:28:28,690 --> 00:28:26,749 early Venus but but he argued that that 773 00:28:31,389 --> 00:28:28,700 the the moist green house effect or what 774 00:28:33,999 --> 00:28:31,399 I call the wet runaway would lose the 775 00:28:36,369 --> 00:28:34,009 water just fine anyway and so you 776 00:28:38,319 --> 00:28:36,379 mentioned that that your stratosphere is 777 00:28:41,919 --> 00:28:38,329 get moist in a lot of these cases and so 778 00:28:45,669 --> 00:28:41,929 I just knew wonder whether that just 779 00:28:48,039 --> 00:28:45,679 negates this whole added ability 780 00:28:50,709 --> 00:28:48,049 range yeah it's a good point right it 781 00:28:52,120 --> 00:28:50,719 depends on which simulation it is and 782 00:28:54,130 --> 00:28:52,130 the strategies are not all 783 00:28:56,320 --> 00:28:54,140 weighs the same witness and I haven't 784 00:28:57,850 --> 00:28:56,330 done any actual calculations to know you 785 00:29:01,090 --> 00:28:57,860 know what the longevity of those oceans 786 00:29:02,890 --> 00:29:01,100 are I mean in castings paper he loses a 787 00:29:05,320 --> 00:29:02,900 whole Earth's ocean but over four 788 00:29:07,630 --> 00:29:05,330 billion years so it's not like if the 789 00:29:08,890 --> 00:29:07,640 stratosphere is as wet as he says it is 790 00:29:10,570 --> 00:29:08,900 it's gonna lose it in the billionaires 791 00:29:12,700 --> 00:29:10,580 for 500 million years it depends on what 792 00:29:14,260 --> 00:29:12,710 the how much water vapor is up there and 793 00:29:16,090 --> 00:29:14,270 what is the incident flux on the 794 00:29:17,620 --> 00:29:16,100 atmosphere so it depends but you might 795 00:29:21,280 --> 00:29:17,630 like to know that Jim Pollock also wrote 796 00:29:23,590 --> 00:29:21,290 a paper in like this in 1977 I think 797 00:29:25,750 --> 00:29:23,600 where he does the same thing he uses a 798 00:29:28,270 --> 00:29:25,760 1d model he uses a hundred percent cloud 799 00:29:29,410 --> 00:29:28,280 cover for Venus and he gets 300 K for 800 00:29:31,660 --> 00:29:29,420 the surface temperature he's the first 801 00:29:32,980 --> 00:29:31,670 person to ever do that actually funny 802 00:29:35,500 --> 00:29:32,990 enough he didn't know why to use why 803 00:29:36,850 --> 00:29:35,510 he's 100 percent cloud cover but it 804 00:29:41,950 --> 00:29:36,860 turned out it was a good choice for 805 00:29:48,250 --> 00:29:41,960 reasons he didn't understand give you 806 00:29:50,350 --> 00:29:48,260 one more question so I'm gonna make it 807 00:29:51,430 --> 00:29:50,360 two but the first one is quick do you 808 00:29:54,850 --> 00:29:51,440 think we should go back to the surface 809 00:29:56,590 --> 00:29:54,860 of Venus no no okay okay the other is 810 00:29:59,860 --> 00:29:56,600 actually I got a little fixated on a 811 00:30:01,960 --> 00:29:59,870 small point you made about how it 812 00:30:02,860 --> 00:30:01,970 weren't through the impact that forms 813 00:30:04,720 --> 00:30:02,870 the moon the earth 814 00:30:07,090 --> 00:30:04,730 might be tightly synchronized by now 815 00:30:09,340 --> 00:30:07,100 yeah and so there's nice that set our 816 00:30:11,140 --> 00:30:09,350 expectations for exoplanets yes but then 817 00:30:13,390 --> 00:30:11,150 I'm also remembering that during Laura's 818 00:30:16,150 --> 00:30:13,400 talk you referenced some paper that 819 00:30:19,030 --> 00:30:16,160 predicted the planets should in general 820 00:30:20,530 --> 00:30:19,040 have a few impacts during the plant 821 00:30:21,940 --> 00:30:20,540 information process and then I'm 822 00:30:24,220 --> 00:30:21,950 wondering where 3 was what her model 823 00:30:25,720 --> 00:30:24,230 showed I think right and so if we think 824 00:30:28,060 --> 00:30:25,730 that most planets should have some 825 00:30:30,160 --> 00:30:28,070 impact how does that plus this 826 00:30:33,340 --> 00:30:30,170 information set our expectation for 827 00:30:36,970 --> 00:30:33,350 rotation rates terrestrial planet good 828 00:30:39,160 --> 00:30:36,980 question anyone like I said I would like 829 00:30:41,800 --> 00:30:39,170 someone to do the the moon impact for 830 00:30:43,090 --> 00:30:41,810 Venus and tell me can you get retrograde 831 00:30:44,890 --> 00:30:43,100 rotation rate out of that impact 832 00:30:47,080 --> 00:30:44,900 depending on what the rotation rate of 833 00:30:50,940 --> 00:30:47,090 the world was to start it's those are 834 00:30:52,830 --> 00:30:50,950 really good questions yeah we don't know