1 00:00:09,650 --> 00:00:07,820 good afternoon my name is Dorian Brown 2 00:00:12,650 --> 00:00:09,660 with the Office of Communications and 3 00:00:15,350 --> 00:00:12,660 welcome to NASA headquarters today 4 00:00:18,140 --> 00:00:15,360 science update will feature new theories 5 00:00:22,130 --> 00:00:18,150 concerning Jupiter's icy moon Europa 6 00:00:25,210 --> 00:00:22,140 more specifically Hidden Lakes when 7 00:00:28,970 --> 00:00:25,220 Europa in fact what you will hear today 8 00:00:31,279 --> 00:00:28,980 opens up compelling possibilities in the 9 00:00:33,940 --> 00:00:31,289 search for life elsewhere in the 10 00:00:38,450 --> 00:00:33,950 universe and the findings I published in 11 00:00:40,160 --> 00:00:38,460 the journal Nature we're going to have 12 00:00:41,720 --> 00:00:40,170 brief presentations from my speakers 13 00:00:43,610 --> 00:00:41,730 then we'll open it up for questions 14 00:00:46,220 --> 00:00:43,620 starting here in Washington on NASA 15 00:00:48,229 --> 00:00:46,230 centers and our phone lines before we 16 00:00:53,029 --> 00:00:48,239 get started let me introduce you to 17 00:00:59,360 --> 00:00:53,039 today's speakers first up Brittany 18 00:01:02,330 --> 00:00:59,370 Schmidt post-doctorate fellow Institute 19 00:01:08,710 --> 00:01:02,340 for geophysics University of Texas and 20 00:01:12,530 --> 00:01:08,720 Austin Tom Wagner program scientists 21 00:01:16,990 --> 00:01:12,540 across spheric sciences prep science 22 00:01:23,719 --> 00:01:21,320 sorry polar astrobiologists and senior 23 00:01:27,789 --> 00:01:23,729 research scientist NASA's Ames Research 24 00:01:35,359 --> 00:01:33,319 Annelise Proctor planetary scientists at 25 00:01:39,230 --> 00:01:35,369 the Johns Hopkins University Applied 26 00:01:41,810 --> 00:01:39,240 Physics Laboratory in Laurel Maryland so 27 00:01:44,660 --> 00:01:41,820 let's get started and I'll toss it over 28 00:01:46,730 --> 00:01:44,670 to Brittany thanks Wayne well I'm 29 00:01:49,280 --> 00:01:46,740 excited to be here with you today to 30 00:01:52,580 --> 00:01:49,290 tell you a little bit about an icy moon 31 00:01:55,010 --> 00:01:52,590 of Jupiter called Europa which we will 32 00:01:58,459 --> 00:01:55,020 show today evidence from recent work 33 00:02:01,730 --> 00:01:58,469 that my team has done my team Don 34 00:02:04,910 --> 00:02:01,740 Blankenship west paterson and paul shank 35 00:02:08,839 --> 00:02:04,920 and i have worked really hard on this 36 00:02:10,520 --> 00:02:08,849 project and if to put jupiter to put a 37 00:02:12,920 --> 00:02:10,530 rope in a little bit of context this is 38 00:02:13,700 --> 00:02:12,930 an image of Europa if you were to look 39 00:02:16,340 --> 00:02:13,710 up into the night 40 00:02:18,800 --> 00:02:16,350 sky tonight much like Galileo did 400 41 00:02:20,390 --> 00:02:18,810 years ago you would see the brightest 42 00:02:22,670 --> 00:02:20,400 point of light in the sky is actually 43 00:02:24,470 --> 00:02:22,680 Jupiter and if you looked at it with 44 00:02:26,600 --> 00:02:24,480 binoculars or a small telescope you'd 45 00:02:28,970 --> 00:02:26,610 notice four tiny bright flashes of light 46 00:02:31,550 --> 00:02:28,980 these are the Galilean satellites of 47 00:02:34,100 --> 00:02:31,560 these Europa is the second most our 48 00:02:36,290 --> 00:02:34,110 second innermost moon and the first icy 49 00:02:39,140 --> 00:02:36,300 moon of Jupiter Europa is covered by a 50 00:02:42,590 --> 00:02:39,150 thick layer of ice containing a 51 00:02:45,440 --> 00:02:42,600 subsurface ocean and then a deeper rocky 52 00:02:47,180 --> 00:02:45,450 mantle and possibly iron core we're 53 00:02:49,910 --> 00:02:47,190 excited about Europa because it 54 00:02:52,370 --> 00:02:49,920 represents a place that's somehow alien 55 00:02:55,370 --> 00:02:52,380 and yet strangely familiar and maybe a 56 00:02:58,310 --> 00:02:55,380 place where there's existence of life in 57 00:03:00,710 --> 00:02:58,320 the solar system today and so I'm 58 00:03:03,590 --> 00:03:00,720 excited to tell you about lakes on 59 00:03:08,690 --> 00:03:03,600 Europa so if I could have the first 60 00:03:10,790 --> 00:03:08,700 graphic these are two images of geologic 61 00:03:12,800 --> 00:03:10,800 terrain taken by the Galileo spacecraft 62 00:03:15,860 --> 00:03:12,810 and they show what's called chaos 63 00:03:18,290 --> 00:03:15,870 terrain these are broken up regions of 64 00:03:20,690 --> 00:03:18,300 the surface characterized by a hummocky 65 00:03:24,200 --> 00:03:20,700 Brown textured material we call matrix 66 00:03:27,140 --> 00:03:24,210 and large icebergs in many cases which 67 00:03:28,970 --> 00:03:27,150 you can see in both of these images one 68 00:03:30,800 --> 00:03:28,980 of the motivations for this study was to 69 00:03:34,760 --> 00:03:30,810 try to understand why are these two 70 00:03:37,880 --> 00:03:34,770 features so similar and so different on 71 00:03:39,710 --> 00:03:37,890 the Left you're seeing thera macula and 72 00:03:42,170 --> 00:03:39,720 on the right you're saying connemara 73 00:03:45,080 --> 00:03:42,180 chaos connemara chaos is in fact perhaps 74 00:03:48,530 --> 00:03:45,090 the archetype of chaos terrain and gives 75 00:03:49,970 --> 00:03:48,540 us a picture of what Europa's activity 76 00:03:51,110 --> 00:03:49,980 may have looked like and it's been 77 00:03:53,300 --> 00:03:51,120 thought for some time that this 78 00:03:55,850 --> 00:03:53,310 represented the interaction of ice and 79 00:03:59,870 --> 00:03:55,860 water but how that how that actually 80 00:04:03,440 --> 00:03:59,880 works out has been has needed more 81 00:04:06,440 --> 00:04:03,450 explanation and so we went to work on 82 00:04:09,830 --> 00:04:06,450 trying to understand this and so the way 83 00:04:12,380 --> 00:04:09,840 that we gave perspective to the problem 84 00:04:14,180 --> 00:04:12,390 of chaos formation on Europa was to look 85 00:04:17,270 --> 00:04:14,190 at environments on earth where water and 86 00:04:20,000 --> 00:04:17,280 ice interact these two important analogs 87 00:04:22,840 --> 00:04:20,010 or examples of this process here on 88 00:04:26,060 --> 00:04:22,850 earth are sub Glacial volcanoes and 89 00:04:27,230 --> 00:04:26,070 collapsing ice shelves and so in a sub 90 00:04:28,610 --> 00:04:27,240 glacial volcano as 91 00:04:31,010 --> 00:04:28,620 essentially what you have is a heat 92 00:04:33,770 --> 00:04:31,020 source underneath the thick cover of ice 93 00:04:37,150 --> 00:04:33,780 and what it does is to create localized 94 00:04:40,100 --> 00:04:37,160 melt that actually forms a lens shaped 95 00:04:42,559 --> 00:04:40,110 lens shaped lake just below the surface 96 00:04:44,270 --> 00:04:42,569 of the ice what's interesting about that 97 00:04:46,150 --> 00:04:44,280 is that the water kind of sits there and 98 00:04:48,680 --> 00:04:46,160 gets to interact with the ice above in 99 00:04:50,719 --> 00:04:48,690 Antarctica we see great examples of 100 00:04:52,400 --> 00:04:50,729 collapsing ice shelves what these ice 101 00:04:54,680 --> 00:04:52,410 shelves do is they sit there for 102 00:04:56,990 --> 00:04:54,690 millions of years and then fill up with 103 00:04:58,760 --> 00:04:57,000 fractures and then break under their own 104 00:05:00,080 --> 00:04:58,770 weight or with help from the water that 105 00:05:02,960 --> 00:05:00,090 gets into fractures in those 106 00:05:04,969 --> 00:05:02,970 environments and so with that context we 107 00:05:06,439 --> 00:05:04,979 formulated a model for how Europa might 108 00:05:08,089 --> 00:05:06,449 work so I'm going to show you a little 109 00:05:13,370 --> 00:05:08,099 demonstration before I show you an image 110 00:05:15,559 --> 00:05:13,380 so if you imagine that we start off with 111 00:05:18,379 --> 00:05:15,569 Europa basically made up of ice that's 112 00:05:20,390 --> 00:05:18,389 fractured but basically just sitting 113 00:05:22,490 --> 00:05:20,400 there and then we add some water this 114 00:05:24,260 --> 00:05:22,500 water comes up from below is cause it's 115 00:05:26,180 --> 00:05:24,270 melting that's caused by a plume of 116 00:05:28,670 --> 00:05:26,190 material much like a mantle plume on the 117 00:05:31,550 --> 00:05:28,680 earth coming up underneath this brittle 118 00:05:33,560 --> 00:05:31,560 ice and filling it up with water as the 119 00:05:35,570 --> 00:05:33,570 lake forms you actually start to see the 120 00:05:37,399 --> 00:05:35,580 icebergs float you've noticed that these 121 00:05:39,469 --> 00:05:37,409 have been turning around and rotating in 122 00:05:41,330 --> 00:05:39,479 the glass in the case of Europa there's 123 00:05:44,839 --> 00:05:41,340 also a thick material called matrix 124 00:05:46,610 --> 00:05:44,849 material that's crushed up ice that 125 00:05:48,439 --> 00:05:46,620 sticks also on the surface of the water 126 00:05:50,209 --> 00:05:48,449 so you never have liquid water really on 127 00:05:52,219 --> 00:05:50,219 the surface but the water is actually 128 00:05:54,740 --> 00:05:52,229 causing the icebergs to float and rotate 129 00:05:56,209 --> 00:05:54,750 and to break up the ice around it what's 130 00:05:58,520 --> 00:05:56,219 interesting is that if you were to go 131 00:06:01,309 --> 00:05:58,530 back and look at this particular Lake on 132 00:06:02,930 --> 00:06:01,319 Europa much later it would actually be 133 00:06:04,670 --> 00:06:02,940 frozen out it may be resemble something 134 00:06:07,219 --> 00:06:04,680 like this where you've got icebergs and 135 00:06:10,219 --> 00:06:07,229 matrix material pushed up but the entire 136 00:06:11,719 --> 00:06:10,229 thing frozen out and so in the next 137 00:06:13,159 --> 00:06:11,729 slide we have an image of what that 138 00:06:15,230 --> 00:06:13,169 process might look like it's just a 139 00:06:17,719 --> 00:06:15,240 cartoon image on the Left we're showing 140 00:06:19,999 --> 00:06:17,729 a collapsing Lake with icebergs popped 141 00:06:21,740 --> 00:06:20,009 up above the surface and imaged and the 142 00:06:24,820 --> 00:06:21,750 matrix materials starting to fill up 143 00:06:27,290 --> 00:06:24,830 with salt rich water from the lake below 144 00:06:28,969 --> 00:06:27,300 this is the process that breaks up the 145 00:06:31,969 --> 00:06:28,979 surface and causes it to look the way we 146 00:06:34,279 --> 00:06:31,979 think it does on the right hand side we 147 00:06:37,339 --> 00:06:34,289 see a snapshot of this process much 148 00:06:39,379 --> 00:06:37,349 later once the ice or once the water in 149 00:06:41,060 --> 00:06:39,389 the lake has actually frozen out one of 150 00:06:42,920 --> 00:06:41,070 the interesting observations of your 151 00:06:44,330 --> 00:06:42,930 has been that there are Kaos features 152 00:06:46,670 --> 00:06:44,340 that are dropped down below the surface 153 00:06:48,440 --> 00:06:46,680 and cast features they're perched up 154 00:06:51,230 --> 00:06:48,450 above the surface with these dome-like 155 00:06:53,810 --> 00:06:51,240 textures they always have in common some 156 00:06:55,520 --> 00:06:53,820 icebergs or some broken up material but 157 00:06:57,470 --> 00:06:55,530 ones down and ones high and what this 158 00:07:00,050 --> 00:06:57,480 does is to put those in perspective as 159 00:07:01,820 --> 00:07:00,060 kind of like a time scale drop down 160 00:07:05,060 --> 00:07:01,830 means active today with liquid water 161 00:07:08,240 --> 00:07:05,070 lens and frozen out is popped up above 162 00:07:10,130 --> 00:07:08,250 the surface with domes and and and solid 163 00:07:12,440 --> 00:07:10,140 icebergs and so if you go to the next 164 00:07:14,690 --> 00:07:12,450 slide this is that first image that I 165 00:07:16,070 --> 00:07:14,700 showed you of the two Kaos terrains but 166 00:07:17,870 --> 00:07:16,080 in fact in this case we're showing you 167 00:07:21,470 --> 00:07:17,880 the topography overlaid on top of the 168 00:07:24,140 --> 00:07:21,480 image in this image blue means low and 169 00:07:26,060 --> 00:07:24,150 red means high if you look at the image 170 00:07:28,130 --> 00:07:26,070 on the Left which is thera macula you'll 171 00:07:30,590 --> 00:07:28,140 notice that the center of the feature is 172 00:07:33,470 --> 00:07:30,600 depressed down below the surface in fact 173 00:07:35,450 --> 00:07:33,480 as much as 400 to 800 meters which means 174 00:07:38,420 --> 00:07:35,460 that a giant pocket of liquid water 175 00:07:40,040 --> 00:07:38,430 still exists below this body today was 176 00:07:42,320 --> 00:07:40,050 also interesting is just like in this 177 00:07:44,450 --> 00:07:42,330 glass of water the icebergs are popped 178 00:07:46,250 --> 00:07:44,460 up above the surface if we look on the 179 00:07:48,350 --> 00:07:46,260 right image of Connemara chaos you'll 180 00:07:50,750 --> 00:07:48,360 notice that instead the terrain is much 181 00:07:52,580 --> 00:07:50,760 lumpier and it's characterized by this 182 00:07:54,620 --> 00:07:52,590 reddish color which means that the 183 00:07:56,780 --> 00:07:54,630 surface is popped up and it's filled 184 00:07:58,880 --> 00:07:56,790 with water and then frozen and so on the 185 00:08:01,070 --> 00:07:58,890 Left we have an active feature on the 186 00:08:02,930 --> 00:08:01,080 right we have an older feature that had 187 00:08:05,090 --> 00:08:02,940 a lake at one time but might have 188 00:08:07,070 --> 00:08:05,100 already frozen out today we've also 189 00:08:09,170 --> 00:08:07,080 prepared a video for you of the profile 190 00:08:12,440 --> 00:08:09,180 the process might look on Europa so 191 00:08:14,750 --> 00:08:12,450 we're going to show you that as we come 192 00:08:17,930 --> 00:08:14,760 into the video you're going to see we're 193 00:08:20,060 --> 00:08:17,940 flying by Jupiter zooming into Europa 194 00:08:22,310 --> 00:08:20,070 that second second moon of Jupiter 195 00:08:24,650 --> 00:08:22,320 covered with ice and we're snapping into 196 00:08:26,540 --> 00:08:24,660 a thin section so you can see in fact 197 00:08:28,700 --> 00:08:26,550 the process start to happen if you 198 00:08:31,850 --> 00:08:28,710 notice there's warm ice down from the 199 00:08:35,030 --> 00:08:31,860 bottom right near the ocean interface 200 00:08:37,040 --> 00:08:35,040 moving its way up causing warming and 201 00:08:38,810 --> 00:08:37,050 causing melting kind of right in the 202 00:08:40,880 --> 00:08:38,820 middle of the ice shell as that lake 203 00:08:43,459 --> 00:08:40,890 starts to form it brings the surface 204 00:08:46,010 --> 00:08:43,469 down because water takes up less volume 205 00:08:47,930 --> 00:08:46,020 than the ice it replaces so the surface 206 00:08:50,270 --> 00:08:47,940 collapses down the icebergs start to 207 00:08:52,730 --> 00:08:50,280 float around break up the ice around it 208 00:08:54,430 --> 00:08:52,740 and then as it refreezes it's free to 209 00:08:56,139 --> 00:08:54,440 dome back up and 210 00:08:58,840 --> 00:08:56,149 the features that we see today that look 211 00:09:00,910 --> 00:08:58,850 like connemara chaos so this is in fact 212 00:09:04,720 --> 00:09:00,920 what we think it might be like on Europa 213 00:09:07,030 --> 00:09:04,730 as these features are forming and to 214 00:09:09,550 --> 00:09:07,040 turn back to the earth example here is a 215 00:09:11,860 --> 00:09:09,560 video of this process happening in a 216 00:09:13,929 --> 00:09:11,870 Greenland a very similar process what 217 00:09:16,600 --> 00:09:13,939 you're looking at is Jakob saman glacier 218 00:09:19,420 --> 00:09:16,610 as icebergs calve from the front of the 219 00:09:21,579 --> 00:09:19,430 glacier turn over and exist there you go 220 00:09:25,030 --> 00:09:21,589 big big iceberg flipping over and 221 00:09:27,189 --> 00:09:25,040 floating around in a matrix of broken up 222 00:09:29,679 --> 00:09:27,199 brash eyes which is rich in water but 223 00:09:31,090 --> 00:09:29,689 still really a solid so this is what it 224 00:09:35,050 --> 00:09:31,100 might look like on Europa if we were 225 00:09:36,790 --> 00:09:35,060 witnessing it relatively live so Tom 226 00:09:38,350 --> 00:09:36,800 Wagner is going to tell you a little bit 227 00:09:40,329 --> 00:09:38,360 more about the Earth's frozen 228 00:09:43,749 --> 00:09:40,339 environments and if we could have the 229 00:09:45,220 --> 00:09:43,759 first slide I thought we'd start with 230 00:09:46,749 --> 00:09:45,230 just a really brief description of ice 231 00:09:48,460 --> 00:09:46,759 shelves which as brittany pointed out is 232 00:09:50,650 --> 00:09:48,470 probably our best analog for what's 233 00:09:51,999 --> 00:09:50,660 happened with the ice on Europa and what 234 00:09:53,710 --> 00:09:52,009 happens is this you take a place at 235 00:09:55,480 --> 00:09:53,720 Greenland Antarctica you build up a lot 236 00:09:57,340 --> 00:09:55,490 of ice and snow in the middle until it 237 00:09:59,110 --> 00:09:57,350 literally gets miles thick and then it 238 00:10:00,699 --> 00:09:59,120 begins to flow to the sides just like if 239 00:10:02,889 --> 00:10:00,709 I poured honey on the table right here 240 00:10:04,300 --> 00:10:02,899 how it would flow out but what happens 241 00:10:06,639 --> 00:10:04,310 when that ice hits the ocean is that 242 00:10:09,280 --> 00:10:06,649 begins to float and that floating 243 00:10:11,470 --> 00:10:09,290 glacier is what an ice shelf is they can 244 00:10:14,170 --> 00:10:11,480 be many hundreds of feet thick they can 245 00:10:16,389 --> 00:10:14,180 extend out many many many miles hundreds 246 00:10:17,980 --> 00:10:16,399 of miles in some cases in fact the Ross 247 00:10:21,730 --> 00:10:17,990 Ice Shelf is the size of France in 248 00:10:24,100 --> 00:10:21,740 Antarctica next slide but ice shelves 249 00:10:25,600 --> 00:10:24,110 are also remarkably dynamic features 250 00:10:28,990 --> 00:10:25,610 most people had thought they were kind 251 00:10:30,600 --> 00:10:29,000 of stable but here we saw in 2008 the 252 00:10:32,650 --> 00:10:30,610 Wilkins ice shelf in Antarctica 253 00:10:34,509 --> 00:10:32,660 literally over the course of a couple of 254 00:10:36,579 --> 00:10:34,519 weeks it blew apart and one of what my 255 00:10:38,920 --> 00:10:36,589 colleagues describes as the mosh pit and 256 00:10:40,660 --> 00:10:38,930 what happened was this ice as it flowed 257 00:10:42,100 --> 00:10:40,670 out it got a little thinner eventually 258 00:10:43,480 --> 00:10:42,110 it triggered a collapse which then 259 00:10:45,819 --> 00:10:43,490 triggered a further collapse and it 260 00:10:48,400 --> 00:10:45,829 tumbled away like giant dominoes next 261 00:10:50,679 --> 00:10:48,410 slide some of these dominoes though are 262 00:10:52,929 --> 00:10:50,689 miles long and hundreds of feet thick 263 00:10:54,369 --> 00:10:52,939 and they turn over and rotate and also 264 00:10:56,740 --> 00:10:54,379 as brittany point out that matrix 265 00:10:58,210 --> 00:10:56,750 material that we see on europa probably 266 00:11:00,069 --> 00:10:58,220 would look something like this which is 267 00:11:01,929 --> 00:11:00,079 brash ice which is the broken up bits 268 00:11:04,030 --> 00:11:01,939 that fill in beneath these between these 269 00:11:07,299 --> 00:11:04,040 birds as they bump into each other next 270 00:11:08,210 --> 00:11:07,309 slide this process is profoundly 271 00:11:09,980 --> 00:11:08,220 important for us 272 00:11:11,480 --> 00:11:09,990 on earth also and this example is the 273 00:11:12,980 --> 00:11:11,490 Larsen Ice Shelf which is on the 274 00:11:16,220 --> 00:11:12,990 Antarctic Peninsula that extends up 275 00:11:17,990 --> 00:11:16,230 towards South America in 2002 an area 276 00:11:19,400 --> 00:11:18,000 the size of Rhode Island again collapsed 277 00:11:22,100 --> 00:11:19,410 just over the course of a couple of 278 00:11:23,780 --> 00:11:22,110 weeks picture giant tablets just 279 00:11:26,000 --> 00:11:23,790 tumbling away things hundreds of feet 280 00:11:28,880 --> 00:11:26,010 thick right over a giant like as big as 281 00:11:31,280 --> 00:11:28,890 a US state what happened though that was 282 00:11:33,440 --> 00:11:31,290 so remarkable was that the glaciers on 283 00:11:34,850 --> 00:11:33,450 the land behind it off to the left side 284 00:11:37,340 --> 00:11:34,860 of the screen that you're looking at 285 00:11:39,320 --> 00:11:37,350 they sped up dramatically as you kind of 286 00:11:41,000 --> 00:11:39,330 popped the cork or pulled away this ice 287 00:11:43,460 --> 00:11:41,010 shelf some of them increased their speed 288 00:11:45,200 --> 00:11:43,470 Eightfold they went so fast that they 289 00:11:47,510 --> 00:11:45,210 drained all the ice that was behind them 290 00:11:49,580 --> 00:11:47,520 and the surface deflated by over a 291 00:11:52,010 --> 00:11:49,590 hundred and fifty feet in some cases 292 00:11:53,750 --> 00:11:52,020 over six hundred feet in other cases 293 00:11:55,970 --> 00:11:53,760 just over the course of five or six 294 00:11:57,380 --> 00:11:55,980 years so this is really important 295 00:11:59,750 --> 00:11:57,390 because when we try to project future 296 00:12:01,100 --> 00:11:59,760 sea-level rise on the planet we think 297 00:12:02,750 --> 00:12:01,110 that this is probably the most dynamic 298 00:12:04,130 --> 00:12:02,760 element that we have to take into 299 00:12:07,760 --> 00:12:04,140 account because there's ice shelves all 300 00:12:09,080 --> 00:12:07,770 around Antarctica next slide and this is 301 00:12:10,730 --> 00:12:09,090 one of the most important ice shelves 302 00:12:11,690 --> 00:12:10,740 for that sea level rise work that I 303 00:12:15,200 --> 00:12:11,700 spoke about this is the Pine Island 304 00:12:17,120 --> 00:12:15,210 glacier ice shelf and this is we studied 305 00:12:18,290 --> 00:12:17,130 these processes in great detail one 306 00:12:20,270 --> 00:12:18,300 thing you should realize is that it's 307 00:12:22,250 --> 00:12:20,280 not a huge extrapolation to go from what 308 00:12:24,110 --> 00:12:22,260 we're doing on earth to Europa because 309 00:12:25,790 --> 00:12:24,120 we have satellites and aircraft where we 310 00:12:27,950 --> 00:12:25,800 can study these things all the way down 311 00:12:29,420 --> 00:12:27,960 to the base levels in this case what 312 00:12:31,220 --> 00:12:29,430 you're looking at the grey is the 313 00:12:32,900 --> 00:12:31,230 surface of the ice shelf which was shot 314 00:12:34,640 --> 00:12:32,910 by lidar from an aircraft literally a 315 00:12:36,920 --> 00:12:34,650 little laser rastering over the surface 316 00:12:38,480 --> 00:12:36,930 underneath that the next layer that kind 317 00:12:40,310 --> 00:12:38,490 of mountainous coloured stuff is the 318 00:12:42,500 --> 00:12:40,320 base of the ice shelf which was with 319 00:12:44,270 --> 00:12:42,510 radar as amazing as it sounds we can put 320 00:12:45,710 --> 00:12:44,280 a radar under an airplane and map the 321 00:12:47,480 --> 00:12:45,720 structure of the ice and the bottom of 322 00:12:49,130 --> 00:12:47,490 the ice under there would be the ocean 323 00:12:51,410 --> 00:12:49,140 and then the bottom is actually the seat 324 00:12:52,610 --> 00:12:51,420 flow which we map by a gravimeter it's 325 00:12:55,400 --> 00:12:52,620 really important to us because again 326 00:12:57,230 --> 00:12:55,410 like the Europa case where you have warm 327 00:12:59,360 --> 00:12:57,240 water that's causing melting and 328 00:13:01,760 --> 00:12:59,370 fracturing and things what our big fear 329 00:13:03,620 --> 00:13:01,770 on earth is that warm water in the ocean 330 00:13:05,810 --> 00:13:03,630 is getting underneath these ice shelves 331 00:13:07,370 --> 00:13:05,820 and destabilizing them and what we have 332 00:13:08,570 --> 00:13:07,380 to do is we have to get the topography 333 00:13:09,860 --> 00:13:08,580 of the under ice shelf we have to get 334 00:13:12,140 --> 00:13:09,870 the topography of the seafloor 335 00:13:14,840 --> 00:13:12,150 to understand how coastal waters mix in 336 00:13:16,550 --> 00:13:14,850 next slide but the last slide that I 337 00:13:18,890 --> 00:13:16,560 want to show you is actually a radar 338 00:13:20,270 --> 00:13:18,900 image over a sub glacial lake literally 339 00:13:21,259 --> 00:13:20,280 like one of these perch lakes we're 340 00:13:23,179 --> 00:13:21,269 talking about on your 341 00:13:25,699 --> 00:13:23,189 in Antarctica there are only over a 342 00:13:27,259 --> 00:13:25,709 hundred and forty of these lakes it's it 343 00:13:29,179 --> 00:13:27,269 was shocking to me I started working in 344 00:13:30,739 --> 00:13:29,189 the Antarctic world probably about seven 345 00:13:32,840 --> 00:13:30,749 or eight years ago we didn't really know 346 00:13:34,819 --> 00:13:32,850 there was that much water around and now 347 00:13:37,040 --> 00:13:34,829 to radar studies like this that vertical 348 00:13:38,869 --> 00:13:37,050 scale is about four kilometres and you 349 00:13:40,549 --> 00:13:38,879 see the flat line in the bottom that's 350 00:13:42,889 --> 00:13:40,559 where the radar waves have bounced off 351 00:13:45,590 --> 00:13:42,899 the surface of the lake that lake is the 352 00:13:47,030 --> 00:13:45,600 size of Lake Ontario and with that I'll 353 00:13:49,160 --> 00:13:47,040 pass off to Tori who's gonna tell us 354 00:13:50,989 --> 00:13:49,170 about habitability on Europa thanks Tom 355 00:13:52,970 --> 00:13:50,999 so one of the things that makes Europa 356 00:13:55,340 --> 00:13:52,980 so exciting that has made it such a 357 00:13:57,139 --> 00:13:55,350 compelling object of study for decades 358 00:13:59,540 --> 00:13:57,149 is the presence of this liquid water 359 00:14:00,889 --> 00:13:59,550 ocean that meets one of the critical 360 00:14:03,319 --> 00:14:00,899 requirements for life and what you're 361 00:14:05,239 --> 00:14:03,329 hearing about today from Brittany bears 362 00:14:06,799 --> 00:14:05,249 on a second of life crucial requirements 363 00:14:09,259 --> 00:14:06,809 and that is the requirement for energy 364 00:14:10,790 --> 00:14:09,269 so habitability is a concept that we all 365 00:14:12,889 --> 00:14:10,800 can relate to personal experience as 366 00:14:14,150 --> 00:14:12,899 living organisms anybody on the street 367 00:14:15,829 --> 00:14:14,160 could give you a pretty good accounting 368 00:14:19,309 --> 00:14:15,839 of what it takes to stay alive water 369 00:14:20,629 --> 00:14:19,319 food shelter air to breathe so if we 370 00:14:22,309 --> 00:14:20,639 think about these things in the context 371 00:14:24,169 --> 00:14:22,319 of Europa there is absolutely no 372 00:14:26,419 --> 00:14:24,179 shortage of water there that we know and 373 00:14:27,980 --> 00:14:26,429 have known for more than a decade as far 374 00:14:29,569 --> 00:14:27,990 as we know the environment is relatively 375 00:14:31,429 --> 00:14:29,579 sheltering if we think about shelter is 376 00:14:33,949 --> 00:14:31,439 the set of conditions that allow life to 377 00:14:35,480 --> 00:14:33,959 persist in an environmental context most 378 00:14:36,829 --> 00:14:35,490 of what we can see can conceive as a 379 00:14:39,530 --> 00:14:36,839 potential your open ocean chemistry 380 00:14:41,569 --> 00:14:39,540 would be reasonably suitable for life 381 00:14:42,980 --> 00:14:41,579 but the big an open question has been 382 00:14:45,049 --> 00:14:42,990 one of energy and when we talk about 383 00:14:46,280 --> 00:14:45,059 food to eat and air to breathe what 384 00:14:48,619 --> 00:14:46,290 we're really talking about is our 385 00:14:50,239 --> 00:14:48,629 requirement for energy and I've tried to 386 00:14:51,769 --> 00:14:50,249 conceptualize how to how to think of 387 00:14:53,629 --> 00:14:51,779 this in terms of a figure so you could 388 00:14:56,929 --> 00:14:53,639 view Europa as something like a great 389 00:14:58,429 --> 00:14:56,939 big battery it's stored energy and the 390 00:15:00,350 --> 00:14:58,439 question has been whether or not that 391 00:15:04,039 --> 00:15:00,360 stored energy is actually available for 392 00:15:06,109 --> 00:15:04,049 life on Europa so if you took a normal 393 00:15:07,730 --> 00:15:06,119 d-cell battery and cut it away what we 394 00:15:09,769 --> 00:15:07,740 would see is chemically different layers 395 00:15:11,569 --> 00:15:09,779 that are isolated from one another its 396 00:15:13,220 --> 00:15:11,579 energy that's stored and the way to tap 397 00:15:15,710 --> 00:15:13,230 that energy as you can see in the second 398 00:15:16,910 --> 00:15:15,720 slide is to connect the terminals when 399 00:15:18,919 --> 00:15:16,920 you connect the terminals with a wire 400 00:15:20,329 --> 00:15:18,929 electrons flow from place to place that 401 00:15:22,129 --> 00:15:20,339 flow of electrons is what we call 402 00:15:23,840 --> 00:15:22,139 electricity but in essence what's 403 00:15:25,789 --> 00:15:23,850 happening is a movement of material from 404 00:15:28,220 --> 00:15:25,799 the outer layer to the inner layer that 405 00:15:30,139 --> 00:15:28,230 serves to release energy so in the next 406 00:15:32,360 --> 00:15:30,149 slide you can see that we can view 407 00:15:34,220 --> 00:15:32,370 Europa in much the same way we know from 408 00:15:34,790 --> 00:15:34,230 spacecraft observations of surface 409 00:15:39,230 --> 00:15:34,800 chemistry 410 00:15:41,150 --> 00:15:39,240 Europa's crust that it represents in 411 00:15:43,880 --> 00:15:41,160 essence stored energy but with this big 412 00:15:45,650 --> 00:15:43,890 thick 10 kilometer or more I show the 413 00:15:47,240 --> 00:15:45,660 big open question has been does that 414 00:15:49,100 --> 00:15:47,250 energy ever get released is it ever 415 00:15:50,600 --> 00:15:49,110 available in the ocean what you're 416 00:15:52,730 --> 00:15:50,610 hearing about here today if we can have 417 00:15:54,949 --> 00:15:52,740 the last slide would be a way to take 418 00:15:56,630 --> 00:15:54,959 this surface material transport it 419 00:15:59,240 --> 00:15:56,640 potentially down into the ocean and in 420 00:16:00,829 --> 00:15:59,250 essence tap Europa's battery and you tap 421 00:16:02,300 --> 00:16:00,839 that battery you've moved from a system 422 00:16:04,550 --> 00:16:02,310 that checks one of the requirements for 423 00:16:06,199 --> 00:16:04,560 a life to a system that checks a second 424 00:16:07,670 --> 00:16:06,209 critical requirement for life and I 425 00:16:10,310 --> 00:16:07,680 think this really impacts the way that 426 00:16:11,360 --> 00:16:10,320 we consider habitability on Europa so 427 00:16:13,639 --> 00:16:11,370 how should we view this in the big 428 00:16:15,350 --> 00:16:13,649 context of your open ocean exploration I 429 00:16:18,410 --> 00:16:15,360 think Louise is the person to address 430 00:16:20,780 --> 00:16:18,420 this thank you sorry well this new model 431 00:16:22,400 --> 00:16:20,790 is very exciting in many respects 432 00:16:24,740 --> 00:16:22,410 because it ties together a lot of loose 433 00:16:27,319 --> 00:16:24,750 ends from Europa studies that have 434 00:16:31,030 --> 00:16:27,329 spanned most the last decade here in the 435 00:16:33,680 --> 00:16:31,040 first slide I am showing a figure that 436 00:16:36,319 --> 00:16:33,690 represents two previous models for 437 00:16:38,960 --> 00:16:36,329 Europa's shell the one on the left shows 438 00:16:40,579 --> 00:16:38,970 the ocean and the ice shell the total 439 00:16:42,650 --> 00:16:40,589 thickness of this is about 150 440 00:16:44,500 --> 00:16:42,660 kilometers but here the shell is 441 00:16:47,449 --> 00:16:44,510 depicted as being very thin maybe only 442 00:16:50,420 --> 00:16:47,459 five kilometers or less and the plumes 443 00:16:52,460 --> 00:16:50,430 that you're seeing here would be in the 444 00:16:54,769 --> 00:16:52,470 ocean there hydrothermal plumes from the 445 00:16:57,319 --> 00:16:54,779 floor from where the ocean floor meets 446 00:16:59,900 --> 00:16:57,329 the mantle of Europa on the right hand 447 00:17:02,180 --> 00:16:59,910 side is a depiction of a thicker shell 448 00:17:04,730 --> 00:17:02,190 model where the shell here would be 449 00:17:07,850 --> 00:17:04,740 about 15 to 30 kilometers it's not quite 450 00:17:09,169 --> 00:17:07,860 to scale but the underlying plumes from 451 00:17:11,210 --> 00:17:09,179 the ocean floor would impinge on the 452 00:17:13,760 --> 00:17:11,220 bottom of the ice shell and would warm 453 00:17:15,949 --> 00:17:13,770 it and as such would create plumes 454 00:17:18,650 --> 00:17:15,959 within the shell these are convective 455 00:17:20,090 --> 00:17:18,660 plumes so it's actually solid material 456 00:17:21,710 --> 00:17:20,100 that is mobilized because it's slightly 457 00:17:23,510 --> 00:17:21,720 warmer than their surroundings so 458 00:17:26,120 --> 00:17:23,520 similar to what you would see in a 459 00:17:28,130 --> 00:17:26,130 saucepan of bubbling soup I'm told me so 460 00:17:30,020 --> 00:17:28,140 soup does this very well but you can see 461 00:17:32,150 --> 00:17:30,030 different convection cells and material 462 00:17:34,340 --> 00:17:32,160 moves upwards in the center and down at 463 00:17:36,860 --> 00:17:34,350 the margins and these two models have 464 00:17:38,360 --> 00:17:36,870 been used to explain some of the 465 00:17:41,270 --> 00:17:38,370 observations we've seen on the surface 466 00:17:43,220 --> 00:17:41,280 of Europa but neither of them have been 467 00:17:43,730 --> 00:17:43,230 able to explain everything we see and 468 00:17:46,070 --> 00:17:43,740 that's been 469 00:17:47,330 --> 00:17:46,080 big problem for us but with a new model 470 00:17:49,190 --> 00:17:47,340 that Brittany and her colleagues have 471 00:17:51,560 --> 00:17:49,200 put together we can now explain pretty 472 00:17:54,350 --> 00:17:51,570 much every geological observation that 473 00:17:56,330 --> 00:17:54,360 we see surrounding chaos on Europa so 474 00:17:57,530 --> 00:17:56,340 it's really sort of come along and and 475 00:18:00,530 --> 00:17:57,540 joined together 476 00:18:03,320 --> 00:18:00,540 a lot of dots so we're very happy to see 477 00:18:06,950 --> 00:18:03,330 that next I want to talk about the 478 00:18:09,740 --> 00:18:06,960 distribution of chaos and its age if you 479 00:18:11,960 --> 00:18:09,750 look at this image of Europa you can see 480 00:18:14,540 --> 00:18:11,970 that the surface looks very different 481 00:18:17,060 --> 00:18:14,550 from say the surface of the Moon or 482 00:18:18,860 --> 00:18:17,070 mercury those bodies are very heavily 483 00:18:20,870 --> 00:18:18,870 impact crater they've got a lot of 484 00:18:23,630 --> 00:18:20,880 cratering scars on them 485 00:18:24,980 --> 00:18:23,640 whereas Europa you can see has hardly 486 00:18:27,440 --> 00:18:24,990 any in fact I'm not sure you can even 487 00:18:28,910 --> 00:18:27,450 make any out of this scale now we use 488 00:18:31,010 --> 00:18:28,920 the number of impact craters on the 489 00:18:33,560 --> 00:18:31,020 surface of the body as a proxy for age 490 00:18:35,240 --> 00:18:33,570 we assume that things like comets and 491 00:18:37,669 --> 00:18:35,250 meteorites that are coming into a system 492 00:18:40,340 --> 00:18:37,679 impact the surface on a fairly constant 493 00:18:41,600 --> 00:18:40,350 basis and so if something has a lot of 494 00:18:43,669 --> 00:18:41,610 them that means that it's been sitting 495 00:18:45,380 --> 00:18:43,679 there getting this weathering process 496 00:18:46,910 --> 00:18:45,390 for a very long time whereas if 497 00:18:48,830 --> 00:18:46,920 something doesn't have many craters it's 498 00:18:51,320 --> 00:18:48,840 probably very young and in the case of 499 00:18:54,740 --> 00:18:51,330 Europa something has happened to erase 500 00:18:56,840 --> 00:18:54,750 the impact scars from the surface and in 501 00:18:59,360 --> 00:18:56,850 this case it could be tectonic features 502 00:19:01,549 --> 00:18:59,370 so faults and fractures on the surface 503 00:19:03,410 --> 00:19:01,559 that could erase whatever has come 504 00:19:05,180 --> 00:19:03,420 before it could be some kind of cryo 505 00:19:07,160 --> 00:19:05,190 volcanism and it certainly could be 506 00:19:09,770 --> 00:19:07,170 chaos so if we can start the movie 507 00:19:11,960 --> 00:19:09,780 please and in fact the average age of 508 00:19:14,330 --> 00:19:11,970 Europa is thought to only be about 60 509 00:19:16,010 --> 00:19:14,340 million years now on human timescales 510 00:19:17,870 --> 00:19:16,020 that's a very long time but in 511 00:19:19,490 --> 00:19:17,880 geological timescales that's the blink 512 00:19:22,340 --> 00:19:19,500 of an eye it was almost born yesterday 513 00:19:25,640 --> 00:19:22,350 on the surface so Europa already has a 514 00:19:28,490 --> 00:19:25,650 very young surface age and here we're 515 00:19:31,190 --> 00:19:28,500 zooming into sera macula on the Left 516 00:19:33,799 --> 00:19:31,200 which Britney talked about earlier and a 517 00:19:34,940 --> 00:19:33,809 chaos very close to it Thrace macula on 518 00:19:35,750 --> 00:19:34,950 the right as you can see they're both 519 00:19:38,419 --> 00:19:35,760 quite large 520 00:19:41,419 --> 00:19:38,429 Sarah is about 80 kilometers maybe a 521 00:19:42,890 --> 00:19:41,429 little over 50 miles across and notice 522 00:19:44,570 --> 00:19:42,900 that these are very different from their 523 00:19:47,419 --> 00:19:44,580 surroundings are both very dark 524 00:19:48,919 --> 00:19:47,429 they have unusual scalloped margins as 525 00:19:51,169 --> 00:19:48,929 they don't look like a lot of the long 526 00:19:53,419 --> 00:19:51,179 linear features that we see that appear 527 00:19:54,890 --> 00:19:53,429 to be faults and fractures these two 528 00:19:57,140 --> 00:19:54,900 arrows are pointing towards a 529 00:20:00,140 --> 00:19:57,150 semicircular Frank 530 00:20:01,460 --> 00:20:00,150 system that was once intact we're 531 00:20:03,560 --> 00:20:01,470 looking at the two sides in it and you 532 00:20:06,049 --> 00:20:03,570 can see that Thrace macula on the right 533 00:20:08,420 --> 00:20:06,059 has actually disrupted the middle of 534 00:20:10,340 --> 00:20:08,430 that is completely destroyed in fact and 535 00:20:12,590 --> 00:20:10,350 so this shows that this chaos region 536 00:20:14,630 --> 00:20:12,600 over lies those tectonic features and so 537 00:20:17,210 --> 00:20:14,640 it's much younger so what we're showing 538 00:20:20,090 --> 00:20:17,220 here is not only is Europa's surface 539 00:20:22,580 --> 00:20:20,100 young but chaos is very young still and 540 00:20:24,740 --> 00:20:22,590 in fact it's one of the youngest future 541 00:20:27,020 --> 00:20:24,750 types is not the major young land form 542 00:20:29,570 --> 00:20:27,030 on the surface so it's very very young 543 00:20:33,380 --> 00:20:29,580 here I'm just zooming out showing you 544 00:20:35,299 --> 00:20:33,390 the equator there's a big X just off the 545 00:20:36,919 --> 00:20:35,309 center to the left just as the south of 546 00:20:38,630 --> 00:20:36,929 that is connemara chaos which Britney 547 00:20:40,940 --> 00:20:38,640 also mentioned earlier you can see all 548 00:20:43,250 --> 00:20:40,950 this brown mottled material over the 549 00:20:46,370 --> 00:20:43,260 surface all of that is chaos terrain 550 00:20:49,190 --> 00:20:46,380 it's very widespread in fact we think 551 00:20:50,930 --> 00:20:49,200 you know estimates vary because we don't 552 00:20:52,430 --> 00:20:50,940 have particularly good imaging data of 553 00:20:54,590 --> 00:20:52,440 much of Europa but we think it could be 554 00:20:56,990 --> 00:20:54,600 as much as 50 percent of the surface has 555 00:20:59,690 --> 00:20:57,000 been completely destroyed in recent eyes 556 00:21:02,240 --> 00:20:59,700 by this chaos formation and so to 557 00:21:03,919 --> 00:21:02,250 summarize this is very important result 558 00:21:05,780 --> 00:21:03,929 because first of all it draws together 559 00:21:09,290 --> 00:21:05,790 many of the conflicting observations 560 00:21:10,640 --> 00:21:09,300 that we've seen in the last 10 years but 561 00:21:13,850 --> 00:21:10,650 secondly it shows that there could be 562 00:21:16,910 --> 00:21:13,860 these huge hidden lakes in Europa's 563 00:21:19,100 --> 00:21:16,920 shale widespread bodies of water may be 564 00:21:22,640 --> 00:21:19,110 taking up as much as half of the upper 565 00:21:24,680 --> 00:21:22,650 shell of Europa and so chaos regions are 566 00:21:26,660 --> 00:21:24,690 going to be extremely important as 567 00:21:28,910 --> 00:21:26,670 possible future targets for exploration 568 00:21:30,980 --> 00:21:28,920 and with that I'll pass back toward 569 00:21:32,810 --> 00:21:30,990 Wayne thank you thank you all so um what 570 00:21:34,130 --> 00:21:32,820 we're gonna do is we're gonna start here 571 00:21:35,690 --> 00:21:34,140 with a question and if you can wait for 572 00:21:38,299 --> 00:21:35,700 the microphone and give your name and 573 00:21:41,480 --> 00:21:38,309 affiliation and then we'll go to the 574 00:21:43,190 --> 00:21:41,490 phone lines randy Shostak reported with 575 00:21:45,169 --> 00:21:43,200 AOS newspaper of the american 576 00:21:46,910 --> 00:21:45,179 geophysical union this is very 577 00:21:48,830 --> 00:21:46,920 interesting information and some I guess 578 00:21:51,020 --> 00:21:48,840 I have sort of a basic question I'd 579 00:21:55,040 --> 00:21:51,030 appreciate if you could describe further 580 00:21:58,580 --> 00:21:55,050 the other models that you investigated 581 00:22:00,500 --> 00:21:58,590 and explored and perhaps discarded what 582 00:22:02,930 --> 00:22:00,510 are the weaknesses in those models for 583 00:22:04,520 --> 00:22:02,940 describing europa and do you believe 584 00:22:08,480 --> 00:22:04,530 that the model that you've outlined 585 00:22:10,060 --> 00:22:08,490 today is the only model that now is 586 00:22:12,340 --> 00:22:10,070 useful in this 587 00:22:14,320 --> 00:22:12,350 in Europa sufficiently or could there 588 00:22:19,870 --> 00:22:14,330 potentially be other models that might 589 00:22:22,600 --> 00:22:19,880 be useful here for a long time we've 590 00:22:25,450 --> 00:22:22,610 thought that Kaos terrain is formed in 591 00:22:28,390 --> 00:22:25,460 the presence of some amount of water one 592 00:22:30,760 --> 00:22:28,400 of the key unknowns is how you get those 593 00:22:33,160 --> 00:22:30,770 surfaces like connemara chaos to 594 00:22:35,770 --> 00:22:33,170 actually produce domes up above the 595 00:22:38,710 --> 00:22:35,780 surface it's actually very hard to do 596 00:22:40,480 --> 00:22:38,720 with most models there have been a 597 00:22:42,370 --> 00:22:40,490 couple of models suggested at all highly 598 00:22:46,000 --> 00:22:42,380 two of them one is that you completely 599 00:22:48,040 --> 00:22:46,010 melt the ice shell and that that the 600 00:22:50,410 --> 00:22:48,050 matrix material represents places where 601 00:22:52,240 --> 00:22:50,420 liquid water flowed on the surface that 602 00:22:54,100 --> 00:22:52,250 has some problems just because of the 603 00:22:56,170 --> 00:22:54,110 cold surface temperatures of Europa and 604 00:22:57,850 --> 00:22:56,180 because other observations of Europa 605 00:23:00,670 --> 00:22:57,860 suggest that the shell is incredibly 606 00:23:03,430 --> 00:23:00,680 thick on the other hand there's been 607 00:23:06,310 --> 00:23:03,440 models of convection and diapir ISM 608 00:23:09,430 --> 00:23:06,320 where the goal was to try to look at if 609 00:23:12,460 --> 00:23:09,440 plumes could survive up into the surface 610 00:23:14,710 --> 00:23:12,470 ice - cause that doming well if you 611 00:23:17,020 --> 00:23:14,720 relaxed that constraint and think about 612 00:23:20,110 --> 00:23:17,030 what happens when ice actually gets 613 00:23:22,840 --> 00:23:20,120 heated is it melts and so in fact the 614 00:23:26,110 --> 00:23:22,850 opposite of what what was the goal 615 00:23:27,940 --> 00:23:26,120 happens and that as the ice melts it 616 00:23:30,340 --> 00:23:27,950 contracts and causes the surface to 617 00:23:32,380 --> 00:23:30,350 depress but what that also does is it 618 00:23:34,660 --> 00:23:32,390 gives a chance for the surface to break 619 00:23:36,760 --> 00:23:34,670 up to fracture just like ice shelves on 620 00:23:38,740 --> 00:23:36,770 the earth why that's important is that 621 00:23:41,730 --> 00:23:38,750 we see icebergs on Europa 622 00:23:44,020 --> 00:23:41,740 seem to follow pre-existing lines 623 00:23:45,310 --> 00:23:44,030 fractures that already existed so it's 624 00:23:47,260 --> 00:23:45,320 like it's being opened up from the 625 00:23:49,600 --> 00:23:47,270 bottom water is getting in there and 626 00:23:51,520 --> 00:23:49,610 breaking off those chunks of ice when 627 00:23:53,230 --> 00:23:51,530 you do that you've mixed up all the 628 00:23:56,020 --> 00:23:53,240 other stuff we mentioned a mosh pit of 629 00:23:58,390 --> 00:23:56,030 ice earlier as those big strong icebergs 630 00:24:00,640 --> 00:23:58,400 move around they can break up all of the 631 00:24:03,070 --> 00:24:00,650 weak ice in between which can fill with 632 00:24:05,860 --> 00:24:03,080 water still not be liquid but fill with 633 00:24:08,050 --> 00:24:05,870 water as you freeze that out the 634 00:24:10,300 --> 00:24:08,060 expansion happens again so just as the 635 00:24:12,670 --> 00:24:10,310 ice when it melted caused thermal 636 00:24:15,130 --> 00:24:12,680 contraction when it refreezes it causes 637 00:24:17,140 --> 00:24:15,140 thermal expansion and that gives you the 638 00:24:19,180 --> 00:24:17,150 extra boost needed to kind of pop that 639 00:24:22,990 --> 00:24:19,190 surface back up into a dome because 640 00:24:23,560 --> 00:24:23,000 you've entrained salt rich water into 641 00:24:28,270 --> 00:24:23,570 that 642 00:24:30,280 --> 00:24:28,280 texture on the surface so it's not the 643 00:24:32,560 --> 00:24:30,290 only model that's out there but one of 644 00:24:35,500 --> 00:24:32,570 the exciting things about it is that it 645 00:24:37,780 --> 00:24:35,510 does kind of explain why we see icebergs 646 00:24:39,360 --> 00:24:37,790 which might seem to think seem to make 647 00:24:42,370 --> 00:24:39,370 you think that the ice shell is thin but 648 00:24:46,170 --> 00:24:42,380 also this matrix material in these domes 649 00:24:51,090 --> 00:24:49,690 okay let's go to the phone lines and 650 00:24:53,710 --> 00:24:51,100 we're gonna head out to the west coast 651 00:24:59,230 --> 00:24:53,720 with David Pearlman from the San 652 00:25:04,570 --> 00:24:59,240 Francisco Chronicle David hey thank you 653 00:25:07,570 --> 00:25:04,580 very much just two questions quickly one 654 00:25:10,090 --> 00:25:07,580 is a NASA seems to have placed a 655 00:25:13,690 --> 00:25:10,100 priority in the search for lights on 656 00:25:18,250 --> 00:25:13,700 life on these Jovian moons and others 657 00:25:20,890 --> 00:25:18,260 and Enceladus and Titan seem to be the 658 00:25:24,460 --> 00:25:20,900 higher priority targets are you people 659 00:25:28,540 --> 00:25:24,470 making a pitch for more attention being 660 00:25:32,910 --> 00:25:28,550 paid to Europa and if so how do you make 661 00:25:36,940 --> 00:25:32,920 that pitch besides a forum like this and 662 00:25:40,210 --> 00:25:36,950 incidentally is this theory about chaos 663 00:25:44,080 --> 00:25:40,220 terrain being published or has it been 664 00:25:48,670 --> 00:25:44,090 published in the literature and I'll 665 00:25:50,740 --> 00:25:48,680 take the answer right now I think what 666 00:25:53,170 --> 00:25:50,750 we're saying is that Europa continues to 667 00:25:56,320 --> 00:25:53,180 be an interesting priority for 668 00:26:00,010 --> 00:25:56,330 exploration which it has been for for 30 669 00:26:02,680 --> 00:26:00,020 years or more yes the the paper has been 670 00:26:05,530 --> 00:26:02,690 published it was just released advanced 671 00:26:08,350 --> 00:26:05,540 online publication by Nature today and 672 00:26:12,100 --> 00:26:08,360 will appear in the print version of the 673 00:26:17,320 --> 00:26:12,110 magazine next week can I just add to 674 00:26:20,340 --> 00:26:17,330 that the the National Academy of 675 00:26:23,440 --> 00:26:20,350 Sciences published a decadal survey for 676 00:26:25,660 --> 00:26:23,450 exploration which was the science 677 00:26:27,820 --> 00:26:25,670 community giving NASA its suggested 678 00:26:29,810 --> 00:26:27,830 priorities for exploration of the next 679 00:26:31,190 --> 00:26:29,820 and I was actually part of the 680 00:26:33,230 --> 00:26:31,200 satellites panel that looks at both 681 00:26:35,390 --> 00:26:33,240 Titan and Europa and they are both 682 00:26:37,790 --> 00:26:35,400 considered to be extremely important 683 00:26:39,950 --> 00:26:37,800 targets and both have astrobiological 684 00:26:42,470 --> 00:26:39,960 potential for different reasons 685 00:26:45,530 --> 00:26:42,480 but at this time that panel felt that 686 00:26:48,080 --> 00:26:45,540 Europa was more compelling and partly 687 00:26:50,540 --> 00:26:48,090 because Titan does need some technology 688 00:26:52,520 --> 00:26:50,550 development to do certain types of 689 00:26:54,710 --> 00:26:52,530 missions there so they are both very 690 00:26:56,090 --> 00:26:54,720 important targets but at this time it 691 00:26:57,770 --> 00:26:56,100 was felt that you know the 692 00:27:02,000 --> 00:26:57,780 recommendation from that panel was that 693 00:27:06,620 --> 00:27:02,010 Patsy Roper was of a higher priority at 694 00:27:08,650 --> 00:27:06,630 the moment okay I actually have two 695 00:27:10,820 --> 00:27:08,660 questions here the first one is for 696 00:27:13,490 --> 00:27:10,830 Brittany from one of the dot-coms and 697 00:27:15,770 --> 00:27:13,500 then for Tom Wagner so the question is 698 00:27:18,170 --> 00:27:15,780 very simple what are the next steps with 699 00:27:20,900 --> 00:27:18,180 presenting this in the data that you 700 00:27:24,970 --> 00:27:20,910 have now I'm glad to answer that 701 00:27:27,560 --> 00:27:24,980 question for us the next steps with 702 00:27:29,060 --> 00:27:27,570 understanding chaos formation and 703 00:27:31,850 --> 00:27:29,070 whether this Lake model really is 704 00:27:35,690 --> 00:27:31,860 correct is to look at the entire surface 705 00:27:38,690 --> 00:27:35,700 there's still data to be used in the 706 00:27:41,210 --> 00:27:38,700 Galileo archives that we can use to 707 00:27:44,270 --> 00:27:41,220 compare this model to other models and 708 00:27:46,100 --> 00:27:44,280 really rigorously test it and then and 709 00:27:47,870 --> 00:27:46,110 then we'll be ready to go on and test 710 00:27:54,610 --> 00:27:47,880 hypotheses in the future with 711 00:27:56,570 --> 00:27:54,620 exploration as the earth scientists 712 00:27:58,700 --> 00:27:56,580 personally what are your feelings on 713 00:28:00,920 --> 00:27:58,710 what you're seeing here how it relates 714 00:28:02,540 --> 00:28:00,930 to your research I think it's fantastic 715 00:28:04,370 --> 00:28:02,550 you know we don't have that many of 716 00:28:06,080 --> 00:28:04,380 these examples even on the earth of ice 717 00:28:08,030 --> 00:28:06,090 shelves collapsing so anytime we can go 718 00:28:09,500 --> 00:28:08,040 and see something like this and also the 719 00:28:10,550 --> 00:28:09,510 scale is tremendous you know that's one 720 00:28:12,710 --> 00:28:10,560 of the things the Europa scale is a 721 00:28:14,150 --> 00:28:12,720 little bit bigger but that in the future 722 00:28:14,750 --> 00:28:14,160 may be something that's more relevant to 723 00:28:16,220 --> 00:28:14,760 us here on earth 724 00:28:17,750 --> 00:28:16,230 so I think it's an exciting research 725 00:28:19,850 --> 00:28:17,760 example for us to continue to work 726 00:28:23,150 --> 00:28:19,860 together on we have any other questions 727 00:28:25,010 --> 00:28:23,160 here good I guess I'd just like to 728 00:28:27,770 --> 00:28:25,020 follow up on that last question that was 729 00:28:29,270 --> 00:28:27,780 asked in your response during your 730 00:28:32,270 --> 00:28:29,280 presentation and talked a lot about what 731 00:28:33,920 --> 00:28:32,280 the earth might help us to how the earth 732 00:28:35,450 --> 00:28:33,930 might help us to understand Europa if 733 00:28:37,160 --> 00:28:35,460 you can elaborate a little bit more on 734 00:28:39,740 --> 00:28:37,170 how Europa might help us to understand 735 00:28:41,360 --> 00:28:39,750 more about Earth processes yeah sure you 736 00:28:42,710 --> 00:28:41,370 know one of the big things is 737 00:28:44,420 --> 00:28:42,720 we're kind of in a new state on the 738 00:28:48,020 --> 00:28:44,430 planet you know and when we try to 739 00:28:49,549 --> 00:28:48,030 understand say the Pine Island area we 740 00:28:51,350 --> 00:28:49,559 try to understand that large large large 741 00:28:53,990 --> 00:28:51,360 ice shelf and how it's going to interact 742 00:28:55,940 --> 00:28:54,000 with the art with the ocean how one of 743 00:28:58,970 --> 00:28:55,950 the theories right now is this that 744 00:29:01,400 --> 00:28:58,980 you've got lack of sea ice and anomalous 745 00:29:03,230 --> 00:29:01,410 winds blowing warm water up onto the 746 00:29:05,810 --> 00:29:03,240 continental shelf around Antarctica and 747 00:29:06,980 --> 00:29:05,820 that's causing the ice shelves to thin 748 00:29:09,230 --> 00:29:06,990 and that's causing something to 749 00:29:10,580 --> 00:29:09,240 destabilize and breakup well we've seen 750 00:29:12,470 --> 00:29:10,590 that happen but we've only seen it 751 00:29:14,150 --> 00:29:12,480 happen right now in kind of small places 752 00:29:16,040 --> 00:29:14,160 around the fringe how is it gonna happen 753 00:29:18,140 --> 00:29:16,050 in bigger places you know what's gonna 754 00:29:20,330 --> 00:29:18,150 happen is that warm water gets in deeper 755 00:29:21,380 --> 00:29:20,340 and said something that we're gonna get 756 00:29:23,660 --> 00:29:21,390 are just simple things even like 757 00:29:25,040 --> 00:29:23,670 geometric constraints right like you 758 00:29:27,140 --> 00:29:25,050 know what's gonna happen to a really 759 00:29:29,030 --> 00:29:27,150 thick area as it breaks up and something 760 00:29:30,650 --> 00:29:29,040 that I didn't talk that much about the 761 00:29:32,419 --> 00:29:30,660 Wilkins Ice Shelf that I showed first 762 00:29:33,590 --> 00:29:32,429 the reason for show that's so 763 00:29:35,960 --> 00:29:33,600 interesting is that it was kind of 764 00:29:37,700 --> 00:29:35,970 mechanical breakup in that the ice shelf 765 00:29:38,720 --> 00:29:37,710 had flowed out and as it flows out in 766 00:29:40,490 --> 00:29:38,730 the ocean and gets thinner and thinner 767 00:29:41,960 --> 00:29:40,500 and thinner just like I say picture it 768 00:29:43,760 --> 00:29:41,970 like spreading pancake batter you know 769 00:29:45,230 --> 00:29:43,770 it just gets thinner as it goes out and 770 00:29:47,660 --> 00:29:45,240 then eventually destabilizes and breaks 771 00:29:49,370 --> 00:29:47,670 up and it triggers with the larsen ice 772 00:29:50,900 --> 00:29:49,380 shelf case one of the theories is that 773 00:29:52,669 --> 00:29:50,910 you had surface melting so you had 774 00:29:54,650 --> 00:29:52,679 warming of the surrounding area of water 775 00:29:56,000 --> 00:29:54,660 form and then kind of like the Europa 776 00:29:58,760 --> 00:29:56,010 example except kind of in the reverse 777 00:30:00,760 --> 00:29:58,770 way that water percolated down forced 778 00:30:02,660 --> 00:30:00,770 its way through cracks created cracks 779 00:30:04,760 --> 00:30:02,670 destabilize the ice shelf and it could 780 00:30:05,900 --> 00:30:04,770 break apart along those things so 781 00:30:07,700 --> 00:30:05,910 there's you know those are kind of two 782 00:30:09,350 --> 00:30:07,710 end member cases that we're trying to 783 00:30:12,710 --> 00:30:09,360 test between and Europe is now another 784 00:30:15,049 --> 00:30:12,720 example for us to think about okay what 785 00:30:17,600 --> 00:30:15,059 we're gonna do is actually they've done 786 00:30:18,830 --> 00:30:17,610 such a great job explaining that we have 787 00:30:20,780 --> 00:30:18,840 no further questions on the line 788 00:30:22,160 --> 00:30:20,790 although we have numerous media that are 789 00:30:24,950 --> 00:30:22,170 listening in so I want to thank you all 790 00:30:30,140 --> 00:30:24,960 for joining us obviously information go