1 00:00:11,610 --> 00:00:08,910 we have the first part of our session 2 00:00:13,920 --> 00:00:11,620 today talks about exoplanets I'm so 3 00:00:15,990 --> 00:00:13,930 planets around other stars and how we're 4 00:00:18,359 --> 00:00:16,000 beginning to characterize them the 5 00:00:20,460 --> 00:00:18,369 second half of the sessions that we have 6 00:00:22,260 --> 00:00:20,470 today talks a little bit about earth 7 00:00:24,750 --> 00:00:22,270 analog environments for the planets in 8 00:00:27,210 --> 00:00:24,760 our own system so I wanted to go through 9 00:00:29,700 --> 00:00:27,220 a little bit of an introduction on what 10 00:00:32,009 --> 00:00:29,710 we have on the earth that allows us to 11 00:00:35,610 --> 00:00:32,019 learn about other planets and other 12 00:00:39,030 --> 00:00:35,620 objects in our solar system so the first 13 00:00:45,000 --> 00:00:39,040 question this might not work all right 14 00:00:47,969 --> 00:00:45,010 that's fine I'll stand over here great 15 00:00:49,680 --> 00:00:47,979 okay all right so we'll always will 16 00:00:51,469 --> 00:00:49,690 probably always have more data on the 17 00:00:54,450 --> 00:00:51,479 earth that we have one of anything else 18 00:00:56,130 --> 00:00:54,460 we're all here on the planet Earth it's 19 00:00:57,810 --> 00:00:56,140 much easier to get to places on the 20 00:00:59,490 --> 00:00:57,820 planet Earth than it is to go anywhere 21 00:01:00,869 --> 00:00:59,500 else so as much as we're all super 22 00:01:02,700 --> 00:01:00,879 interested in stuff which is not on 23 00:01:05,219 --> 00:01:02,710 earth if we can find a place on earth 24 00:01:08,090 --> 00:01:05,229 which looks very like the place that we 25 00:01:10,200 --> 00:01:08,100 would prefer to be then that's great 26 00:01:12,420 --> 00:01:10,210 also earth is the only planet with 27 00:01:15,539 --> 00:01:12,430 ubiquitous life right so we have an 28 00:01:17,880 --> 00:01:15,549 example here of an inhabited world and 29 00:01:19,230 --> 00:01:17,890 if we go anywhere on the earth right so 30 00:01:20,910 --> 00:01:19,240 far everywhere we've gone we've been 31 00:01:24,029 --> 00:01:20,920 able to find some organism which is 32 00:01:26,249 --> 00:01:24,039 living there thriving there so if you 33 00:01:28,349 --> 00:01:26,259 can go to an environment which is very 34 00:01:31,139 --> 00:01:28,359 like the surface of Mars say or very 35 00:01:33,419 --> 00:01:31,149 like the subsurface ocean on Europa and 36 00:01:35,730 --> 00:01:33,429 find life there well maybe you found 37 00:01:38,849 --> 00:01:35,740 candidate organisms that we might 38 00:01:40,889 --> 00:01:38,859 someday find on those other planets and 39 00:01:42,690 --> 00:01:40,899 then the other great thing about Earth 40 00:01:44,370 --> 00:01:42,700 is that we've been sort of in this 41 00:01:46,709 --> 00:01:44,380 cosmic minefield for four and a half 42 00:01:48,270 --> 00:01:46,719 billion years scooping up little bits of 43 00:01:50,370 --> 00:01:48,280 other planets that happen to be 44 00:01:53,039 --> 00:01:50,380 wandering around the solar system so 45 00:01:55,889 --> 00:01:53,049 we've got two talks this afternoon about 46 00:01:57,029 --> 00:01:55,899 Martian meteorites and then additional 47 00:01:59,399 --> 00:01:57,039 talks which are about meteorites which 48 00:02:01,200 --> 00:01:59,409 aren't from Mars these are samples of 49 00:02:03,149 --> 00:02:01,210 the rest of the universe which have 50 00:02:05,389 --> 00:02:03,159 landed on the earth and then been found 51 00:02:08,760 --> 00:02:05,399 by scientists and these are great 52 00:02:10,490 --> 00:02:08,770 laboratories for studying these objects 53 00:02:13,740 --> 00:02:10,500 because so far the only thing we've done 54 00:02:15,839 --> 00:02:13,750 to bring back parts of other objects in 55 00:02:18,970 --> 00:02:15,849 the solar system is bring back tiny I 56 00:02:23,360 --> 00:02:18,980 screens from a comment 57 00:02:24,620 --> 00:02:23,370 okay so a little bit about meteorites so 58 00:02:27,980 --> 00:02:24,630 there's a bunch of different classes of 59 00:02:30,050 --> 00:02:27,990 meteorite maybe the most important when 60 00:02:32,360 --> 00:02:30,060 you talk about the chemicals of life or 61 00:02:34,370 --> 00:02:32,370 finding chemicals of life in the 62 00:02:37,160 --> 00:02:34,380 universe are these carbonaceous 63 00:02:40,610 --> 00:02:37,170 chondrites so they're called chondrites 64 00:02:43,940 --> 00:02:40,620 because they have con jewels here's a 65 00:02:45,050 --> 00:02:43,950 con drool right this little speck here 66 00:02:47,540 --> 00:02:45,060 and there's lots of these other little 67 00:02:50,500 --> 00:02:47,550 circular spherical inclusions in 68 00:02:52,580 --> 00:02:50,510 meteorites which are called chondrules I 69 00:02:54,920 --> 00:02:52,590 don't know why they're called chondrules 70 00:02:57,890 --> 00:02:54,930 it comes from like some greek root 71 00:02:59,300 --> 00:02:57,900 probably that means spherical so the 72 00:03:02,240 --> 00:02:59,310 chondrules are surrounded by this dark 73 00:03:03,560 --> 00:03:02,250 matrix so if people talk about the 74 00:03:06,200 --> 00:03:03,570 matrix they're not talking about that 75 00:03:08,450 --> 00:03:06,210 movie they're talking about this dark 76 00:03:09,710 --> 00:03:08,460 organic rich material which cements 77 00:03:12,890 --> 00:03:09,720 together everything else in the 78 00:03:14,870 --> 00:03:12,900 meteorite so organics are most abundant 79 00:03:17,360 --> 00:03:14,880 in the matrix of chondritic meteorites 80 00:03:18,920 --> 00:03:17,370 or carbonaceous chondrites i'm so called 81 00:03:22,610 --> 00:03:18,930 because they have a lot of carbon that's 82 00:03:24,680 --> 00:03:22,620 what makes them black so if you actually 83 00:03:27,229 --> 00:03:24,690 go and scoop out a little bit of this 84 00:03:29,150 --> 00:03:27,239 matrix and look for organic molecules 85 00:03:32,360 --> 00:03:29,160 amino acids what have you you'll find 86 00:03:34,070 --> 00:03:32,370 them there so here's just a list of a 87 00:03:36,380 --> 00:03:34,080 whole bunch of different compounds which 88 00:03:37,760 --> 00:03:36,390 have been found in i believe the 89 00:03:40,310 --> 00:03:37,770 merchants and meteorite and this is a 90 00:03:42,770 --> 00:03:40,320 picture of the Murchison meteorite here 91 00:03:45,920 --> 00:03:42,780 I'm zsuzsa meteorite which fell in 92 00:03:48,350 --> 00:03:45,930 Australia people saw this streak of a 93 00:03:51,410 --> 00:03:48,360 meteorite meteor streaking across the 94 00:03:53,930 --> 00:03:51,420 sky landed just outside of town and like 95 00:03:55,970 --> 00:03:53,940 the whole town drove out there and their 96 00:03:57,560 --> 00:03:55,980 pickup trucks and found the meteorite 97 00:04:01,130 --> 00:03:57,570 some people reported that it had a very 98 00:04:02,540 --> 00:04:01,140 strong smell like ammonia and then they 99 00:04:04,699 --> 00:04:02,550 loaded it in the back of a pickup truck 100 00:04:06,410 --> 00:04:04,709 brought it into town put it in a bank 101 00:04:09,110 --> 00:04:06,420 vault and immediately called the 102 00:04:13,040 --> 00:04:09,120 scientists like a hundred percent 103 00:04:15,920 --> 00:04:13,050 correct great job because these people 104 00:04:17,690 --> 00:04:15,930 preserve the meteorite from alteration 105 00:04:19,120 --> 00:04:17,700 most meteorites that we find have been 106 00:04:21,530 --> 00:04:19,130 sitting there for god knows how long 107 00:04:24,320 --> 00:04:21,540 they've been subject to weathering on 108 00:04:26,480 --> 00:04:24,330 the Earth's surface but these people got 109 00:04:28,730 --> 00:04:26,490 there in time to smell the organics 110 00:04:30,230 --> 00:04:28,740 coming off of the meteorite and then 111 00:04:31,140 --> 00:04:30,240 they immediately put it in a sterile 112 00:04:35,760 --> 00:04:31,150 environment and call 113 00:04:37,560 --> 00:04:35,770 the experts so here's an example of 114 00:04:38,790 --> 00:04:37,570 stuff that's been found in these 115 00:04:40,440 --> 00:04:38,800 meteorites if you're sufficiently 116 00:04:42,420 --> 00:04:40,450 impressive you can like right away to 117 00:04:44,910 --> 00:04:42,430 NASA and say please send me part of a 118 00:04:46,860 --> 00:04:44,920 meteorite and they will send you part of 119 00:04:49,500 --> 00:04:46,870 a meteorite um you can also go and buy 120 00:04:51,840 --> 00:04:49,510 slightly less rare meteorites at your 121 00:04:53,670 --> 00:04:51,850 local gem and mineral show so if you 122 00:04:55,500 --> 00:04:53,680 haven't like an extra 50 bucks and you 123 00:04:59,670 --> 00:04:55,510 want a piece of space you can go there 124 00:05:02,610 --> 00:04:59,680 and purchase one yeah so in addition to 125 00:05:04,890 --> 00:05:02,620 just finding this stuff in these in the 126 00:05:08,870 --> 00:05:04,900 matrix of these meteorites you can also 127 00:05:11,430 --> 00:05:08,880 do a lot of detailed analysis of the 128 00:05:13,620 --> 00:05:11,440 particular kinds of amino acids that 129 00:05:15,330 --> 00:05:13,630 you're finding the particular abundances 130 00:05:17,790 --> 00:05:15,340 of the organic molecules that you find 131 00:05:19,350 --> 00:05:17,800 and the abundances that you see might 132 00:05:21,510 --> 00:05:19,360 give clues to the formation conditions 133 00:05:23,520 --> 00:05:21,520 so basically you build a laboratory 134 00:05:25,530 --> 00:05:23,530 meteorite under a bunch of different 135 00:05:27,360 --> 00:05:25,540 temperature pressure conditions you run 136 00:05:29,220 --> 00:05:27,370 a bunch of syntheses and you see what 137 00:05:30,750 --> 00:05:29,230 you get out in terms of the abundance of 138 00:05:33,240 --> 00:05:30,760 the amino acids that you produce and 139 00:05:34,260 --> 00:05:33,250 this might tell you something about what 140 00:05:35,730 --> 00:05:34,270 the conditions were like in the 141 00:05:39,420 --> 00:05:35,740 meteorite when those amino acids were 142 00:05:42,450 --> 00:05:39,430 forming and in addition some people 143 00:05:45,960 --> 00:05:42,460 think that these organic molecules were 144 00:05:47,940 --> 00:05:45,970 the seeds of life so life and organic 145 00:05:49,860 --> 00:05:47,950 molecules didn't begin on the earth it 146 00:05:51,750 --> 00:05:49,870 began in meteorites and then was brought 147 00:05:56,010 --> 00:05:51,760 to the earth and then the organic 148 00:05:57,300 --> 00:05:56,020 molecules provided the start of life I 149 00:05:58,890 --> 00:05:57,310 mean I don't know if you've seen 150 00:06:01,590 --> 00:05:58,900 recently it's been going around on 151 00:06:04,020 --> 00:06:01,600 facebook and all over the place like 152 00:06:06,510 --> 00:06:04,030 scientists old 3.5 billion year old 153 00:06:09,330 --> 00:06:06,520 mystery of life and it's basically one 154 00:06:11,340 --> 00:06:09,340 particular group has this idea that if 155 00:06:14,220 --> 00:06:11,350 only they could get a fancy kind of 156 00:06:15,690 --> 00:06:14,230 phosphate they could make life and then 157 00:06:18,330 --> 00:06:15,700 they said let's just get it from 158 00:06:20,580 --> 00:06:18,340 meteorites we'll bring it all in from 159 00:06:22,050 --> 00:06:20,590 outer space all these meteorites will in 160 00:06:24,420 --> 00:06:22,060 on the earth and give us the phosphates 161 00:06:28,020 --> 00:06:24,430 that we need in order to start life out 162 00:06:30,810 --> 00:06:28,030 so not so much solving a 3.5 billion 163 00:06:34,080 --> 00:06:30,820 year old mystery as pushing it back a 164 00:06:41,210 --> 00:06:34,090 step to actually being in the meteorites 165 00:06:44,100 --> 00:06:41,220 and now I need to log in again all right 166 00:06:45,740 --> 00:06:44,110 okay so questions worth asking when we 167 00:06:47,820 --> 00:06:45,750 talk about amino acids and meteorites 168 00:06:49,350 --> 00:06:47,830 how well-known are the formation 169 00:06:52,350 --> 00:06:49,360 mechanisms right so we talked about 170 00:06:54,720 --> 00:06:52,360 maybe characterizing a meteorite on the 171 00:06:56,280 --> 00:06:54,730 basis of running a bunch of reactions in 172 00:06:58,530 --> 00:06:56,290 the lab right you can only run certain 173 00:07:00,090 --> 00:06:58,540 reactions so how well do we know what 174 00:07:01,830 --> 00:07:00,100 mechanisms might have been operating in 175 00:07:03,960 --> 00:07:01,840 the meteorites when the amino acids 176 00:07:07,320 --> 00:07:03,970 actually formed and if we're looking at 177 00:07:10,080 --> 00:07:07,330 meteorites is a source for for what 178 00:07:11,790 --> 00:07:10,090 happened early on in Earth history maybe 179 00:07:13,200 --> 00:07:11,800 a source for the phosphates are the 180 00:07:15,180 --> 00:07:13,210 organic molecules that you need to get 181 00:07:16,740 --> 00:07:15,190 life going it's worthwhile to ask 182 00:07:18,390 --> 00:07:16,750 whether the meteorites that fell on 183 00:07:20,160 --> 00:07:18,400 earth when life was beginning even or 184 00:07:21,570 --> 00:07:20,170 even still around right the Earth's 185 00:07:23,060 --> 00:07:21,580 surface has been highly processed over 186 00:07:25,890 --> 00:07:23,070 the last four and a half billion years 187 00:07:27,630 --> 00:07:25,900 maybe we don't even have samples of the 188 00:07:29,690 --> 00:07:27,640 stuff that fell on the earth and might 189 00:07:31,740 --> 00:07:29,700 have gotten life started um and 190 00:07:34,070 --> 00:07:31,750 questions always worth asking whenever 191 00:07:36,510 --> 00:07:34,080 people say oh life came from space is 192 00:07:40,530 --> 00:07:36,520 what would there have even been a high 193 00:07:43,140 --> 00:07:40,540 enough impact flux right to matter could 194 00:07:45,240 --> 00:07:43,150 you ever have put enough stuff on the 195 00:07:47,280 --> 00:07:45,250 surface of the earth that you could get 196 00:07:50,310 --> 00:07:47,290 these things started so even if you have 197 00:07:53,130 --> 00:07:50,320 no idea what people to say in the talk 198 00:07:55,200 --> 00:07:53,140 on meteorites or origin of life beyond 199 00:07:57,120 --> 00:07:55,210 Earth you can ask any of these questions 200 00:08:00,870 --> 00:07:57,130 and they better have a good answer at 201 00:08:03,600 --> 00:08:00,880 least a scientific sounding answer okay 202 00:08:05,370 --> 00:08:03,610 so another analog environment that 203 00:08:08,220 --> 00:08:05,380 people look at Britney this afternoon is 204 00:08:11,790 --> 00:08:08,230 going to be talking about ice and in 205 00:08:13,650 --> 00:08:11,800 particular life under ice um so some 206 00:08:16,050 --> 00:08:13,660 people think that if you want to get 207 00:08:19,310 --> 00:08:16,060 life started you need oh Sh ins worth of 208 00:08:22,200 --> 00:08:19,320 water in contact with a silicate 209 00:08:24,150 --> 00:08:22,210 exterior of a planet right so it's not 210 00:08:27,440 --> 00:08:24,160 enough to just have like one pond on the 211 00:08:29,760 --> 00:08:27,450 surface of Mars you need a whole ocean 212 00:08:31,800 --> 00:08:29,770 not everybody is on board with that but 213 00:08:34,770 --> 00:08:31,810 some people really believe that you need 214 00:08:36,990 --> 00:08:34,780 a whole ocean and in contact with a 215 00:08:38,640 --> 00:08:37,000 silicate crust and if you believe that 216 00:08:41,160 --> 00:08:38,650 then one of the best places to look for 217 00:08:44,760 --> 00:08:41,170 life in the solar system may be in the 218 00:08:47,250 --> 00:08:44,770 universe are the Jovian moons because 219 00:08:49,230 --> 00:08:47,260 they actually have more water in contact 220 00:08:51,810 --> 00:08:49,240 with more silicate mantle than the earth 221 00:08:53,460 --> 00:08:51,820 does so 222 00:08:55,680 --> 00:08:53,470 if you believe that life can only begin 223 00:08:58,260 --> 00:08:55,690 when you have an ocean in contact with a 224 00:09:00,300 --> 00:08:58,270 silicate crust then you want to go 225 00:09:01,650 --> 00:09:00,310 Europa and look for stuff there and 226 00:09:06,450 --> 00:09:01,660 there's a couple places so let's go 227 00:09:08,010 --> 00:09:06,460 let's go to Europa so if you're on the 228 00:09:09,420 --> 00:09:08,020 surface of Europa right there are a 229 00:09:12,000 --> 00:09:09,430 couple ideas for where you might have 230 00:09:15,240 --> 00:09:12,010 your like cactus right living here 231 00:09:17,520 --> 00:09:15,250 getting some sunlight but you need to 232 00:09:19,620 --> 00:09:17,530 always be asking where the nutrients 233 00:09:21,270 --> 00:09:19,630 coming from where are the oxidants 234 00:09:23,940 --> 00:09:21,280 coming from where the reductants coming 235 00:09:27,060 --> 00:09:23,950 from complex life on earth requires 236 00:09:31,650 --> 00:09:27,070 oxygen we get that oxygen from oxygenic 237 00:09:35,970 --> 00:09:31,660 photosynthesis and if you think about 238 00:09:40,770 --> 00:09:35,980 these systems where deep under the 239 00:09:45,510 --> 00:09:40,780 Earth's oceans we have superheated water 240 00:09:48,480 --> 00:09:45,520 but then also oxygen in the oceans which 241 00:09:50,460 --> 00:09:48,490 is acting as a battery that life is 242 00:09:52,260 --> 00:09:50,470 exploiting right so you've got oxidants 243 00:09:54,150 --> 00:09:52,270 coming in from outside you've got 244 00:09:56,850 --> 00:09:54,160 reductants coming out from the inside of 245 00:09:59,550 --> 00:09:56,860 the earth and life can exploit the fact 246 00:10:02,280 --> 00:09:59,560 that oxidation wants to happen in order 247 00:10:05,340 --> 00:10:02,290 to exist but you need an oxidant and you 248 00:10:07,170 --> 00:10:05,350 need a reductant on Europa the idea is 249 00:10:09,630 --> 00:10:07,180 that you can take a whole bunch of stuff 250 00:10:13,080 --> 00:10:09,640 from the ambient environment around 251 00:10:16,650 --> 00:10:13,090 Jupiter smash it into the surface and 252 00:10:19,710 --> 00:10:16,660 then take that stuff under the shell so 253 00:10:21,660 --> 00:10:19,720 that you introduce a lot of oxidants 254 00:10:23,550 --> 00:10:21,670 into the Europa environment and that's 255 00:10:26,940 --> 00:10:23,560 the only way that you could get a source 256 00:10:28,890 --> 00:10:26,950 of oxidation for the life that may or 257 00:10:30,530 --> 00:10:28,900 may not exist inside like your little 258 00:10:34,650 --> 00:10:30,540 cockroaches that may or may not exist 259 00:10:35,760 --> 00:10:34,660 near in the near surface of Europa so I 260 00:10:39,210 --> 00:10:35,770 think Brittany's going to talk about 261 00:10:42,300 --> 00:10:39,220 finding stuff underneath the ice that 262 00:10:44,250 --> 00:10:42,310 has been found in Antarctica so this is 263 00:10:46,020 --> 00:10:44,260 maybe a new environment most people when 264 00:10:47,730 --> 00:10:46,030 they think of Europa they think of this 265 00:10:49,740 --> 00:10:47,740 kind of environment black smoke or deep 266 00:10:51,570 --> 00:10:49,750 underneath the ocean we'd have to send 267 00:10:53,580 --> 00:10:51,580 like a submarine all the way down to the 268 00:10:55,560 --> 00:10:53,590 bottom of the ocean on Europa but maybe 269 00:10:58,470 --> 00:10:55,570 we could find life really close 270 00:10:59,640 --> 00:10:58,480 underneath the ice I'm so questions 271 00:11:01,110 --> 00:10:59,650 worth asking you know where is 272 00:11:03,660 --> 00:11:01,120 everything coming from what's the source 273 00:11:05,190 --> 00:11:03,670 of nutrients oxidants reductants and 274 00:11:07,200 --> 00:11:05,200 energy and 275 00:11:10,350 --> 00:11:07,210 how quickly could any of those be de 276 00:11:14,280 --> 00:11:10,360 plena SH by life we've depleted by life 277 00:11:16,080 --> 00:11:14,290 or replenished by life so you can't just 278 00:11:18,090 --> 00:11:16,090 have all four of these things in one 279 00:11:21,060 --> 00:11:18,100 place for 30 minutes and then you have 280 00:11:22,800 --> 00:11:21,070 life right it may have taken a great 281 00:11:25,260 --> 00:11:22,810 deal of time for life to get started on 282 00:11:26,400 --> 00:11:25,270 the earth so even if you have all four 283 00:11:27,690 --> 00:11:26,410 of these things you need to make sure 284 00:11:29,910 --> 00:11:27,700 that they're there for long enough and 285 00:11:36,000 --> 00:11:29,920 that any life doesn't just get rid of 286 00:11:39,300 --> 00:11:36,010 them right away let's go to Mars so Mars 287 00:11:41,250 --> 00:11:39,310 today is very dry there's lots of 288 00:11:43,350 --> 00:11:41,260 evidence for water in the past but if 289 00:11:45,150 --> 00:11:43,360 you put a cup of liquid water out on the 290 00:11:49,170 --> 00:11:45,160 surface of Mars today it would either 291 00:11:51,000 --> 00:11:49,180 boil or freeze so why is that so here's 292 00:11:53,220 --> 00:11:51,010 a plot with temperature on the 293 00:11:55,470 --> 00:11:53,230 horizontal axis pressure on the vertical 294 00:11:57,510 --> 00:11:55,480 axis and this is a phase diagram so at 295 00:11:59,400 --> 00:11:57,520 any particular pressure temperature pair 296 00:12:03,060 --> 00:11:59,410 water will be in one of three phases 297 00:12:05,160 --> 00:12:03,070 right solid liquid or vapor at the earth 298 00:12:07,500 --> 00:12:05,170 which has an atmosphere pressure of one 299 00:12:10,050 --> 00:12:07,510 atmosphere and this temperature range 300 00:12:12,200 --> 00:12:10,060 indicated by the yellow line water can 301 00:12:16,520 --> 00:12:12,210 be in all three phases solid liquid or 302 00:12:19,560 --> 00:12:16,530 gas but at Mars which is that these 303 00:12:21,990 --> 00:12:19,570 Arnold's head exploding pressures of 304 00:12:24,330 --> 00:12:22,000 what point zero zero six atmospheres 305 00:12:27,300 --> 00:12:24,340 right you're down below the triple point 306 00:12:29,520 --> 00:12:27,310 of water so you can never have liquid 307 00:12:31,980 --> 00:12:29,530 water on the surface of Mars I'm you can 308 00:12:34,320 --> 00:12:31,990 only have solid or vapor now this is 309 00:12:35,790 --> 00:12:34,330 water in its pure form right you can 310 00:12:38,520 --> 00:12:35,800 like totally throw a whole bunch of 311 00:12:40,590 --> 00:12:38,530 chloride salts in there and maybe get 312 00:12:43,110 --> 00:12:40,600 water to stay liquid right just like 313 00:12:45,300 --> 00:12:43,120 when they put de-icers on the road the 314 00:12:49,290 --> 00:12:45,310 water stays liquid instead of freezing 315 00:12:51,120 --> 00:12:49,300 and killing everybody all right so 316 00:12:53,300 --> 00:12:51,130 there's lots of evidence for past water 317 00:12:56,430 --> 00:12:53,310 even if they can't be liquid water on 318 00:12:58,020 --> 00:12:56,440 Mars today there's shape evidence or 319 00:13:01,580 --> 00:12:58,030 morphological evidence in the form of 320 00:13:03,960 --> 00:13:01,590 these river deltas all over Mars you see 321 00:13:06,600 --> 00:13:03,970 shapes which can only be formed by water 322 00:13:09,240 --> 00:13:06,610 which was flowing it's still an open 323 00:13:11,610 --> 00:13:09,250 question as to how much water was 324 00:13:13,830 --> 00:13:11,620 required to create these features some 325 00:13:16,380 --> 00:13:13,840 people think that Mars was very cold and 326 00:13:18,130 --> 00:13:16,390 dry even when it was warm and wet right 327 00:13:20,620 --> 00:13:18,140 it was cold and dry in comparison 328 00:13:23,470 --> 00:13:20,630 the earth we can also look at 329 00:13:25,240 --> 00:13:23,480 mineralogical evidence so the color is 330 00:13:27,040 --> 00:13:25,250 in this image which is of jezero crater 331 00:13:30,480 --> 00:13:27,050 I believe it was one of the potential 332 00:13:32,500 --> 00:13:30,490 landing sites for the Curiosity rover 333 00:13:34,690 --> 00:13:32,510 eventually they chose gale crater over 334 00:13:35,980 --> 00:13:34,700 jezero but the reason why it was even 335 00:13:38,890 --> 00:13:35,990 being considered is because of all this 336 00:13:41,560 --> 00:13:38,900 blue and green which is a mineralogical 337 00:13:43,540 --> 00:13:41,570 indication that there are clays there 338 00:13:46,330 --> 00:13:43,550 and these clays on which are called 339 00:13:48,520 --> 00:13:46,340 phyllosilicates because they have silica 340 00:13:52,060 --> 00:13:48,530 and because they're layered like phyllo 341 00:13:54,880 --> 00:13:52,070 dough these clays require water in order 342 00:13:57,280 --> 00:13:54,890 to form so if you have water and you 343 00:13:59,080 --> 00:13:57,290 have silicates you can make a clay make 344 00:14:01,690 --> 00:13:59,090 a phyllosilicate clay and that's what 345 00:14:04,930 --> 00:14:01,700 we're seeing from space here via 346 00:14:08,230 --> 00:14:04,940 infrared spectroscopy at least that's 347 00:14:10,600 --> 00:14:08,240 what we think we're seeing you can never 348 00:14:13,600 --> 00:14:10,610 really be sure until you go there and 349 00:14:15,820 --> 00:14:13,610 pick up a sample and do detailed 350 00:14:18,070 --> 00:14:15,830 mineralogy so we'll have a talk this 351 00:14:19,780 --> 00:14:18,080 afternoon about cerro negro and 352 00:14:21,970 --> 00:14:19,790 Nicaragua which is one of the youngest 353 00:14:26,370 --> 00:14:21,980 volcanoes on the earth Emma when did it 354 00:14:30,820 --> 00:14:28,810 1850 right so there's a historical 355 00:14:32,440 --> 00:14:30,830 record of every single eruption that 356 00:14:33,640 --> 00:14:32,450 Cerro Negro has experienced which means 357 00:14:35,710 --> 00:14:33,650 if you go there and you're like look at 358 00:14:38,200 --> 00:14:35,720 this interesting rock you can like look 359 00:14:40,480 --> 00:14:38,210 up in the historical Almanac exactly 360 00:14:43,140 --> 00:14:40,490 when that rock was in place right 361 00:14:45,040 --> 00:14:43,150 exactly when it happened so we have a 362 00:14:47,050 --> 00:14:45,050 historical record of the formation 363 00:14:53,190 --> 00:14:47,060 environment for every rock that you 364 00:14:56,860 --> 00:14:55,600 for every rock that you might find at 365 00:14:58,330 --> 00:14:56,870 Cerro Negro so you can actually go there 366 00:14:59,890 --> 00:14:58,340 and Emmas going to talk about her work 367 00:15:02,590 --> 00:14:59,900 where she went there with a portable 368 00:15:04,060 --> 00:15:02,600 spectrometer infrared spectrometer put 369 00:15:06,190 --> 00:15:04,070 it right up next to the rock and then 370 00:15:08,350 --> 00:15:06,200 brought those rocks back for analysis so 371 00:15:10,600 --> 00:15:08,360 we can actually do a detailed comparison 372 00:15:11,920 --> 00:15:10,610 of what you might see on the ground to 373 00:15:13,450 --> 00:15:11,930 what you do see from space will have 374 00:15:16,480 --> 00:15:13,460 several other talks about that as well 375 00:15:17,860 --> 00:15:16,490 um so here's what you do here's what you 376 00:15:20,830 --> 00:15:17,870 see from space right here's some more 377 00:15:24,070 --> 00:15:20,840 blue stuff right that blue stuff here is 378 00:15:25,510 --> 00:15:24,080 this iron magnesium smectite clay right 379 00:15:27,400 --> 00:15:25,520 so whenever you hear the word smectite 380 00:15:28,660 --> 00:15:27,410 you should just think clay whenever hear 381 00:15:31,000 --> 00:15:28,670 the word clay you should think water 382 00:15:31,630 --> 00:15:31,010 right so this the idea here is that this 383 00:15:33,910 --> 00:15:31,640 particular 384 00:15:35,650 --> 00:15:33,920 band structure which we think we're 385 00:15:38,820 --> 00:15:35,660 observing based on the fit to the 386 00:15:43,360 --> 00:15:38,830 spacecraft observe spectra is 387 00:15:47,830 --> 00:15:43,370 characteristic of clay so you have this 388 00:15:49,720 --> 00:15:47,840 lava rich unit up here this ultramafic 389 00:15:52,720 --> 00:15:49,730 unit which is basically just love and it 390 00:15:55,000 --> 00:15:52,730 came straight out of a volcano later on 391 00:16:00,310 --> 00:15:55,010 water can flow through and alter that 392 00:16:01,720 --> 00:16:00,320 lava to make the smectite clays so there 393 00:16:03,610 --> 00:16:01,730 are a lot of images like this in the 394 00:16:05,620 --> 00:16:03,620 literature on Mars I'm Bethenny ailment 395 00:16:06,820 --> 00:16:05,630 is a specialist in this sort of thing so 396 00:16:09,900 --> 00:16:06,830 if you've ever read a paper of hers 397 00:16:13,930 --> 00:16:09,910 she's got lots of these images showing 398 00:16:15,430 --> 00:16:13,940 orbital spectra of Mars that say where 399 00:16:18,280 --> 00:16:15,440 the water is but you should always keep 400 00:16:20,260 --> 00:16:18,290 in mind that we need to know what it 401 00:16:22,120 --> 00:16:20,270 looked like what it looks like on the 402 00:16:23,680 --> 00:16:22,130 ground one way that we can tell what it 403 00:16:31,230 --> 00:16:23,690 looks like on the ground is with these 404 00:16:35,740 --> 00:16:33,550 on to Antarctica and they bring their 405 00:16:37,000 --> 00:16:35,750 baseball mitts and they catch meteorites 406 00:16:40,030 --> 00:16:37,010 as they come in right because it's very 407 00:16:41,980 --> 00:16:40,040 wide and flat it's very white so you can 408 00:16:43,300 --> 00:16:41,990 see the meteorites coming and you can 409 00:16:46,720 --> 00:16:43,310 actually go and catch them before they 410 00:16:48,070 --> 00:16:46,730 ever hit the ground so this is this is a 411 00:16:51,190 --> 00:16:48,080 story they tell what they actually do is 412 00:16:54,160 --> 00:16:51,200 they the meteorites land in Antarctica 413 00:16:56,770 --> 00:16:54,170 there's kilometers of ice above any 414 00:16:59,110 --> 00:16:56,780 rocks that came from Earth and then 415 00:17:00,880 --> 00:16:59,120 there's some rocks on top and so if you 416 00:17:04,270 --> 00:17:00,890 see rocks on top of those kilometers of 417 00:17:07,150 --> 00:17:04,280 ice probably they came from space and in 418 00:17:09,040 --> 00:17:07,160 addition they go to particular regions 419 00:17:12,640 --> 00:17:09,050 of Antarctica where the ice has flowed 420 00:17:14,890 --> 00:17:12,650 and been brought up to the surface so 421 00:17:16,510 --> 00:17:14,900 that you get a collection of a very wide 422 00:17:20,170 --> 00:17:16,520 area where the meteorites may have 423 00:17:21,610 --> 00:17:20,180 fallen so they go there they they stay 424 00:17:25,390 --> 00:17:21,620 in tents which are specifically designed 425 00:17:27,579 --> 00:17:25,400 to explode if the weather gets bad 426 00:17:28,780 --> 00:17:27,589 enough so that it doesn't collapse on 427 00:17:30,130 --> 00:17:28,790 you right because the worst thing would 428 00:17:31,990 --> 00:17:30,140 be if the weather gets really bad then 429 00:17:34,120 --> 00:17:32,000 you're like impaled on your tent poles 430 00:17:36,430 --> 00:17:34,130 right so these are like Scott tents 431 00:17:38,400 --> 00:17:36,440 where if the wind gets fast enough that 432 00:17:41,470 --> 00:17:38,410 top will literally blow off of the tent 433 00:17:44,920 --> 00:17:41,480 and they eat like nothing but frozen 434 00:17:45,549 --> 00:17:44,930 steak for months and every day they get 435 00:17:49,899 --> 00:17:45,559 out and 436 00:17:51,519 --> 00:17:49,909 walk like 10 meters away from every 437 00:17:54,489 --> 00:17:51,529 other person in the expedition across 438 00:18:00,399 --> 00:17:54,499 the ice and they look for rocks on top 439 00:18:02,289 --> 00:18:00,409 of the ice so this is the this was found 440 00:18:04,749 --> 00:18:02,299 in the Allen Hills region of Antarctica 441 00:18:06,610 --> 00:18:04,759 in 1984 and it was considered the first 442 00:18:08,769 --> 00:18:06,620 most interesting meteorite they found in 443 00:18:11,320 --> 00:18:08,779 that year because inside this meteorite 444 00:18:12,850 --> 00:18:11,330 or trapped bubbles of gas which exactly 445 00:18:14,850 --> 00:18:12,860 matched the composition of the Martian 446 00:18:21,070 --> 00:18:14,860 atmosphere so this is a piece of Mars 447 00:18:23,350 --> 00:18:21,080 now I have to log in again this came 448 00:18:24,730 --> 00:18:23,360 from Mars we can tell from multiple 449 00:18:26,259 --> 00:18:24,740 lines of evidence not just the bubbles 450 00:18:28,720 --> 00:18:26,269 of gas which are trapped inside it and 451 00:18:30,639 --> 00:18:28,730 so if you're really very very impressive 452 00:18:32,859 --> 00:18:30,649 you can write to NASA and say please 453 00:18:36,970 --> 00:18:32,869 send me a piece of Mars I would like to 454 00:18:39,609 --> 00:18:36,980 do science on it and in the 90s this 455 00:18:42,070 --> 00:18:39,619 meteorite was the subject of much public 456 00:18:43,869 --> 00:18:42,080 fascination because at least one 457 00:18:47,609 --> 00:18:43,879 scientist became convinced that they 458 00:18:50,409 --> 00:18:47,619 were found fossil life in this meteorite 459 00:18:51,460 --> 00:18:50,419 and there were three independent lines 460 00:18:53,230 --> 00:18:51,470 of evidence presented in the original 461 00:18:54,519 --> 00:18:53,240 paper problem is that when you're 462 00:18:56,409 --> 00:18:54,529 talking about finding life on another 463 00:18:58,749 --> 00:18:56,419 planet even three independent lines of 464 00:19:01,239 --> 00:18:58,759 evidence is not enough and subsequently 465 00:19:04,509 --> 00:19:01,249 I believe all three have been separately 466 00:19:09,460 --> 00:19:04,519 shown to be capable of being produced by 467 00:19:13,629 --> 00:19:09,470 abiotic means so I but does anybody 468 00:19:20,169 --> 00:19:13,639 remember the name of the guy Chris McKay 469 00:19:22,779 --> 00:19:20,179 um so he he was conceived McKay was was 470 00:19:26,200 --> 00:19:22,789 uh he believed yeah he believed until 471 00:19:28,749 --> 00:19:26,210 his death that he had found life on Mars 472 00:19:30,070 --> 00:19:28,759 in this meteorite um but you always have 473 00:19:31,299 --> 00:19:30,080 to wonder right because I mean who knows 474 00:19:33,340 --> 00:19:31,309 how long this was sitting there before 475 00:19:35,919 --> 00:19:33,350 nineteen eighty-four right maybe it was 476 00:19:38,169 --> 00:19:35,929 Antarctic life that like got in there 477 00:19:41,590 --> 00:19:38,179 and left those fossils right a million 478 00:19:43,299 --> 00:19:41,600 years ago so we'll have a talk about 479 00:19:45,700 --> 00:19:43,309 differentiating between Antarctic 480 00:19:46,840 --> 00:19:45,710 weathering and meteorites and what may 481 00:19:49,419 --> 00:19:46,850 have been the original formation 482 00:19:52,749 --> 00:19:49,429 environment on Mars and you can tell a 483 00:19:54,450 --> 00:19:52,759 lot from the mineralogy and petrology of 484 00:19:56,499 --> 00:19:54,460 these rocks where they came from on Mars 485 00:19:58,029 --> 00:19:56,509 and I think actually this one turns out 486 00:19:58,670 --> 00:19:58,039 to be a little bit weird and comparison 487 00:20:05,300 --> 00:19:58,680 to the other more 488 00:20:06,950 --> 00:20:05,310 meteorites that all right so questions 489 00:20:08,500 --> 00:20:06,960 worth asking right what alternate 490 00:20:11,450 --> 00:20:08,510 formation mechanisms did you investigate 491 00:20:13,460 --> 00:20:11,460 M is going to talk this afternoon about 492 00:20:16,850 --> 00:20:13,470 her work in sierra negra were actually 493 00:20:19,060 --> 00:20:16,860 they find phyllosilicate clays in this 494 00:20:21,830 --> 00:20:19,070 very definitely volcanic environment 495 00:20:23,570 --> 00:20:21,840 right so there has been a cuius 496 00:20:25,160 --> 00:20:23,580 alteration there but not of the kind 497 00:20:27,260 --> 00:20:25,170 that we would expect in like a riverbed 498 00:20:29,330 --> 00:20:27,270 right so when people see phyllosilicates 499 00:20:30,800 --> 00:20:29,340 on Mars maybe they were formed in a 500 00:20:32,750 --> 00:20:30,810 different way than we would expect maybe 501 00:20:34,310 --> 00:20:32,760 we were fooling ourselves that there's a 502 00:20:36,380 --> 00:20:34,320 lot of water there so you can always ask 503 00:20:38,210 --> 00:20:36,390 what alternate formation mechanism best 504 00:20:39,770 --> 00:20:38,220 agay tanned then all of these studies of 505 00:20:41,270 --> 00:20:39,780 analog environments are always missing 506 00:20:43,730 --> 00:20:41,280 something right because they're on earth 507 00:20:45,260 --> 00:20:43,740 they're not on the other planet so what 508 00:20:47,450 --> 00:20:45,270 is it it's missing what is it that's 509 00:20:50,540 --> 00:20:47,460 wrong about your analog environment what 510 00:20:52,880 --> 00:20:50,550 didn't you consider okay so on 511 00:20:54,410 --> 00:20:52,890 particular analog environment that a lot 512 00:20:57,290 --> 00:20:54,420 of people study are these Antarctic Dry 513 00:21:00,020 --> 00:20:57,300 Valleys so they are right here in 514 00:21:02,630 --> 00:21:00,030 Antarctica these dry valleys and that's 515 00:21:04,190 --> 00:21:02,640 also so if you zoom in on a map of 516 00:21:05,960 --> 00:21:04,200 Antarctica not all of Antarctica is 517 00:21:08,900 --> 00:21:05,970 completely covered in ice parts of it 518 00:21:11,860 --> 00:21:08,910 are very dry and don't experience any 519 00:21:16,460 --> 00:21:11,870 snow over the course of a typical year 520 00:21:17,750 --> 00:21:16,470 so people go to these valleys they're 521 00:21:20,000 --> 00:21:17,760 actually like right here in this 522 00:21:21,620 --> 00:21:20,010 background image of the earth people go 523 00:21:23,120 --> 00:21:21,630 to these valleys and they camp out and 524 00:21:25,310 --> 00:21:23,130 again these tents which are designed to 525 00:21:26,990 --> 00:21:25,320 explode if the weather gets too bad and 526 00:21:29,030 --> 00:21:27,000 these valleys are incredibly well 527 00:21:31,790 --> 00:21:29,040 protected in terms of what you are 528 00:21:33,590 --> 00:21:31,800 required to do in order to go there the 529 00:21:37,040 --> 00:21:33,600 people who go there have to bottle their 530 00:21:38,480 --> 00:21:37,050 urine and take their urine out because 531 00:21:41,210 --> 00:21:38,490 it might contaminate the local 532 00:21:43,340 --> 00:21:41,220 environment and in particular the 533 00:21:45,760 --> 00:21:43,350 microbes that live in this lake down 534 00:21:49,070 --> 00:21:45,770 here wouldn't necessarily like 535 00:21:50,630 --> 00:21:49,080 contaminants getting in there I'm so 536 00:21:51,950 --> 00:21:50,640 these analog environments are really 537 00:21:53,800 --> 00:21:51,960 great for a variety of reasons they're 538 00:21:56,120 --> 00:21:53,810 the coldest driest places on the earth 539 00:21:58,040 --> 00:21:56,130 there's still a heck of a lot warmer and 540 00:22:00,350 --> 00:21:58,050 wetter than a typical place on Mars but 541 00:22:02,030 --> 00:22:00,360 they're the closest that you can get and 542 00:22:05,770 --> 00:22:02,040 occasionally you see things like this 543 00:22:09,440 --> 00:22:05,780 right here forming in these valleys and 544 00:22:11,570 --> 00:22:09,450 these are formed when water flows in the 545 00:22:12,980 --> 00:22:11,580 valley and darkens the soil periodically 546 00:22:15,190 --> 00:22:12,990 we also see these 547 00:22:18,080 --> 00:22:15,200 mars we call them slope streaks there 548 00:22:20,540 --> 00:22:18,090 and they're persistent throughout the 549 00:22:22,280 --> 00:22:20,550 high latitudes on Mars there I believe 550 00:22:24,590 --> 00:22:22,290 they're also seasonal and they've been 551 00:22:27,230 --> 00:22:24,600 observed not only to exist but also to 552 00:22:28,280 --> 00:22:27,240 change over the course of a reasonable 553 00:22:31,100 --> 00:22:28,290 time spent so you'll see them like 554 00:22:33,140 --> 00:22:31,110 expand and propagate there are a lot of 555 00:22:35,299 --> 00:22:33,150 proposed formation mechanisms for these 556 00:22:36,980 --> 00:22:35,309 some of which do not require water which 557 00:22:38,510 --> 00:22:36,990 gets back to that question right what 558 00:22:40,520 --> 00:22:38,520 alternate formation mechanisms might 559 00:22:43,100 --> 00:22:40,530 there be just because this thing we see 560 00:22:45,460 --> 00:22:43,110 on the earth requires water doesn't mean 561 00:22:48,620 --> 00:22:45,470 that these things that we see on Mars 562 00:22:50,630 --> 00:22:48,630 necessarily require water I'm still have 563 00:22:53,240 --> 00:22:50,640 a talk about slope streaks this 564 00:22:54,770 --> 00:22:53,250 afternoon another thing that you see in 565 00:22:59,299 --> 00:22:54,780 these dry valleys are these really brine 566 00:23:01,460 --> 00:22:59,309 rich ponds and if water exists on Mars 567 00:23:05,530 --> 00:23:01,470 today is almost certainly in the form of 568 00:23:08,419 --> 00:23:05,540 brians and one interesting thing that 569 00:23:11,090 --> 00:23:08,429 was recently discovered in 2006 by the 570 00:23:15,530 --> 00:23:11,100 Phoenix lander are perchlorates or 571 00:23:17,090 --> 00:23:15,540 chlorine salts that were found on the 572 00:23:18,470 --> 00:23:17,100 surface of Mars they're completely onyx 573 00:23:20,960 --> 00:23:18,480 they're completely unexpected when they 574 00:23:22,970 --> 00:23:20,970 were found so the Phoenix lander 575 00:23:26,480 --> 00:23:22,980 contained a wet chemistry or a wet soil 576 00:23:28,280 --> 00:23:26,490 analyzer that went to the North Pole of 577 00:23:30,919 --> 00:23:28,290 Mars scooped up a little bit of soil and 578 00:23:33,440 --> 00:23:30,929 looked at what was in that soil found 579 00:23:35,630 --> 00:23:33,450 these perchlorate salts that may explain 580 00:23:38,930 --> 00:23:35,640 one of the mysteries of the early Viking 581 00:23:40,730 --> 00:23:38,940 landers as to why the life detection 582 00:23:43,330 --> 00:23:40,740 experiments at two positives and two 583 00:23:47,390 --> 00:23:43,340 negatives but these perchlorate salts 584 00:23:49,730 --> 00:23:47,400 were found and these are actually really 585 00:23:52,910 --> 00:23:49,740 good at acting as antifreeze for water 586 00:23:55,580 --> 00:23:52,920 so they'll absorb water out of the 587 00:23:57,200 --> 00:23:55,590 atmosphere and create a brine even at 588 00:24:00,500 --> 00:23:57,210 the low water concentrations that you 589 00:24:02,330 --> 00:24:00,510 see in the atmosphere of Mars one 590 00:24:04,040 --> 00:24:02,340 proposed formation mechanism is that 591 00:24:06,080 --> 00:24:04,050 they're produced by UV light interacting 592 00:24:08,210 --> 00:24:06,090 with chloride rich soils so there's a 593 00:24:10,790 --> 00:24:08,220 Death Valley analogue where if you leave 594 00:24:13,850 --> 00:24:10,800 a lot of chloride rich soil out for very 595 00:24:16,790 --> 00:24:13,860 long time under UV light you can maybe 596 00:24:19,850 --> 00:24:16,800 get these perchlorates to form this is a 597 00:24:21,950 --> 00:24:19,860 picture of a trench that was dug by the 598 00:24:23,390 --> 00:24:21,960 Phoenix lander I like to tell my 599 00:24:26,630 --> 00:24:23,400 students when I teach an intro class 600 00:24:28,070 --> 00:24:26,640 that planetary science is still so new 601 00:24:29,870 --> 00:24:28,080 that if you send a shovel to another 602 00:24:34,910 --> 00:24:29,880 planet you're doing literally 603 00:24:36,710 --> 00:24:34,920 groundbreaking science so being excited 604 00:24:39,350 --> 00:24:36,720 this little scoop that scooped out a 605 00:24:41,450 --> 00:24:39,360 little bit of soil and then it saw these 606 00:24:43,490 --> 00:24:41,460 white spots disappear over the course of 607 00:24:47,000 --> 00:24:43,500 several days the interpretation was that 608 00:24:49,130 --> 00:24:47,010 there's subsurface ice all throughout 609 00:24:53,090 --> 00:24:49,140 the north and latitudes of Mars this is 610 00:24:56,180 --> 00:24:53,100 consistent with observations of neutrons 611 00:24:57,710 --> 00:24:56,190 which are made from orbit there's the 612 00:24:59,870 --> 00:24:57,720 subsurface ice mantle tends to absorb 613 00:25:02,900 --> 00:24:59,880 neutrons quite well so there's sort of 614 00:25:05,210 --> 00:25:02,910 gaps in what we would expect in these 615 00:25:12,020 --> 00:25:05,220 northerly latitudes I really got to fix 616 00:25:14,810 --> 00:25:12,030 this login problem I suppose I could 617 00:25:16,880 --> 00:25:14,820 plug in I'm really close to the end so 618 00:25:19,520 --> 00:25:16,890 I'm just going to keep going all right 619 00:25:21,290 --> 00:25:19,530 so questions worth asking right whenever 620 00:25:24,140 --> 00:25:21,300 you talk about an analog environment or 621 00:25:26,540 --> 00:25:24,150 any of these brines or slope streaks you 622 00:25:28,160 --> 00:25:26,550 could ask could any microbe could any 623 00:25:29,420 --> 00:25:28,170 known microbes survive in the 624 00:25:31,870 --> 00:25:29,430 environment that you're talking about 625 00:25:34,370 --> 00:25:31,880 and there are people working on this if 626 00:25:36,500 --> 00:25:34,380 nothing on earth could survive in that 627 00:25:37,850 --> 00:25:36,510 environment well then you have a little 628 00:25:39,410 --> 00:25:37,860 bit more of a case to make about why 629 00:25:42,800 --> 00:25:39,420 this might be Astro biologically 630 00:25:45,050 --> 00:25:42,810 relevant and then how long if there was 631 00:25:47,450 --> 00:25:45,060 life earlier on when conditions were 632 00:25:49,610 --> 00:25:47,460 maybe a little bit better but things got 633 00:25:52,310 --> 00:25:49,620 worse how long would you preserve any 634 00:25:54,380 --> 00:25:52,320 fossil life are these slope streaks a 635 00:25:56,390 --> 00:25:54,390 good place to look for currently extent 636 00:25:58,760 --> 00:25:56,400 microbes right we'll you'll find 637 00:26:00,470 --> 00:25:58,770 microfossils or like little fish fossils 638 00:26:04,760 --> 00:26:00,480 and these slope streaks when the water 639 00:26:06,710 --> 00:26:04,770 burst out it's a worthwhile question to 640 00:26:08,000 --> 00:26:06,720 ask because if you're making a case that 641 00:26:11,450 --> 00:26:08,010 this is an astro biologically 642 00:26:13,910 --> 00:26:11,460 interesting phenomenon we got to talk 643 00:26:16,370 --> 00:26:13,920 about whether or not life could exist or 644 00:26:19,870 --> 00:26:16,380 whether we could see evidence of fossil 645 00:26:22,040 --> 00:26:19,880 life alright so that's all that I have 646 00:26:23,870 --> 00:26:22,050 we're going to have I think that I've 647 00:26:26,630 --> 00:26:23,880 covered everybody's talks that I was 648 00:26:29,150 --> 00:26:26,640 supposed to cover if you have questions 649 00:26:32,330 --> 00:26:29,160 you can either ask me and if i don't 650 00:26:33,740 --> 00:26:32,340 know i will tell you to ask the people 651 00:26:35,120 --> 00:26:33,750 who actually know which is people who 652 00:26:43,680 --> 00:26:35,130 are presenting in the afternoon thanks 653 00:26:43,690 --> 00:27:18,480 question 654 00:27:21,870 --> 00:27:20,520 okay yeah so I'm going to repeat the 655 00:27:24,630 --> 00:27:21,880 question for the benefit of people who 656 00:27:26,220 --> 00:27:24,640 may be watching online so the question 657 00:27:28,260 --> 00:27:26,230 is whether if there is a global 658 00:27:30,390 --> 00:27:28,270 subsurface ice layer or if there is a 659 00:27:33,120 --> 00:27:30,400 subsurface ice layer on Mars what would 660 00:27:36,330 --> 00:27:33,130 be the implications for the stuff that's 661 00:27:37,890 --> 00:27:36,340 above that ice layer in particular when 662 00:27:39,480 --> 00:27:37,900 we talk about Antarctica we have this 663 00:27:42,630 --> 00:27:39,490 thick ice layer the stuff on top is 664 00:27:45,600 --> 00:27:42,640 interpreted as having come from space so 665 00:27:47,520 --> 00:27:45,610 one thing is on Mars on the ice layer is 666 00:27:50,820 --> 00:27:47,530 not necessarily global I misspoke when I 667 00:27:52,380 --> 00:27:50,830 said global earlier so it's mostly in 668 00:27:54,690 --> 00:27:52,390 the northerly latitude so north of about 669 00:27:58,980 --> 00:27:54,700 60 degrees or south of about 60 degrees 670 00:28:01,410 --> 00:27:58,990 latitude and I I'm not entirely sure but 671 00:28:04,590 --> 00:28:01,420 I believe that the idea here is that 672 00:28:06,240 --> 00:28:04,600 very early on in Mars history the water 673 00:28:08,310 --> 00:28:06,250 sort of settled out in the permafrost 674 00:28:10,560 --> 00:28:08,320 layer like very like we have in the 675 00:28:12,780 --> 00:28:10,570 northerly latitudes on the earth so once 676 00:28:14,850 --> 00:28:12,790 Mars gets cold enough the water ice is 677 00:28:16,560 --> 00:28:14,860 stable not on the surface but in the 678 00:28:18,750 --> 00:28:16,570 subsurface right if it's on the surface 679 00:28:21,390 --> 00:28:18,760 it'll vaporize and deposit elsewhere 680 00:28:24,870 --> 00:28:21,400 maybe later get buried so you could get 681 00:28:28,980 --> 00:28:24,880 like layers of soil and ice and soil and 682 00:28:30,990 --> 00:28:28,990 ice and I mean as far as I know Phoenix 683 00:28:32,730 --> 00:28:31,000 Doug like a couple trenches and then 684 00:28:35,880 --> 00:28:32,740 that was it right it was buried under 685 00:28:39,110 --> 00:28:35,890 the seasonal co2 frost which is 686 00:28:41,190 --> 00:28:39,120 deposited every winter on Mars and then 687 00:28:42,810 --> 00:28:41,200 so if you want you could send a bigger 688 00:28:45,360 --> 00:28:42,820 shovel and that would be like a 689 00:28:48,330 --> 00:28:45,370 geologist dream send a bigger shovel to 690 00:28:51,360 --> 00:28:48,340 Mars really scoop out some stuff and see 691 00:28:53,940 --> 00:28:51,370 if we can like see the strata you see it 692 00:28:57,030 --> 00:28:53,950 a lot in road cuts on the earth right 693 00:28:59,310 --> 00:28:57,040 when you cut through a ridge and you can 694 00:29:01,320 --> 00:28:59,320 see the layers right geologists would 695 00:29:02,970 --> 00:29:01,330 love to do that on Mars right build it 696 00:29:10,380 --> 00:29:02,980 build a highway on Mars and then drive