1 00:00:04,070 --> 00:00:02,270 good evening ladies and gentlemen and 2 00:00:06,559 --> 00:00:04,080 welcome to the Space Telescope Science 3 00:00:08,299 --> 00:00:06,569 Institute I'm your host dr. Frank 4 00:00:12,140 --> 00:00:08,309 summers and it is my pleasure to welcome 5 00:00:14,539 --> 00:00:12,150 you for our public lecture series when 6 00:00:16,460 --> 00:00:14,549 you came in I hope that you are 7 00:00:19,370 --> 00:00:16,470 accustomed now to getting pretty 8 00:00:21,370 --> 00:00:19,380 pictures either on that table or I got 9 00:00:24,019 --> 00:00:21,380 smart I put them on this side as well so 10 00:00:26,810 --> 00:00:24,029 tonight's pretty picture that we have is 11 00:00:29,450 --> 00:00:26,820 the core of the globular cluster omega 12 00:00:30,679 --> 00:00:29,460 centauri if that doesn't make any sense 13 00:00:32,450 --> 00:00:30,689 to you turnover 14 00:00:34,639 --> 00:00:32,460 there are a few hundred words to explain 15 00:00:37,310 --> 00:00:34,649 it on the back and if you want to know 16 00:00:40,369 --> 00:00:37,320 even more tom says he's going to be 17 00:00:42,350 --> 00:00:40,379 featuring this in part of his talk 18 00:00:46,279 --> 00:00:42,360 tonight you didn't get it on your way in 19 00:00:48,740 --> 00:00:46,289 please grab one on the way out our talk 20 00:00:50,840 --> 00:00:48,750 tonight is on the trail of the missing 21 00:00:54,979 --> 00:00:50,850 galaxies the oldest stars in the 22 00:00:57,590 --> 00:00:54,989 neighborhood by Tom Brown coming up next 23 00:01:00,439 --> 00:00:57,600 month we have a multi-wavelength view of 24 00:01:03,650 --> 00:01:00,449 stellar life in death in the galaxy 25 00:01:05,560 --> 00:01:03,660 Messier 83 by Bill Blair who's from 26 00:01:08,420 --> 00:01:05,570 across the street at Johns Hopkins 27 00:01:11,810 --> 00:01:08,430 November first we have the infinite the 28 00:01:14,090 --> 00:01:11,820 infamous TBA which means I'm trying to 29 00:01:15,679 --> 00:01:14,100 get somebody to talk I was hoping 30 00:01:17,840 --> 00:01:15,689 somebody will come in and do a talk like 31 00:01:21,289 --> 00:01:17,850 make the universe great again right 32 00:01:23,240 --> 00:01:21,299 because of course this is one week 33 00:01:25,880 --> 00:01:23,250 before Election Day it's not election 34 00:01:27,590 --> 00:01:25,890 night usually in election years my 35 00:01:29,870 --> 00:01:27,600 November talk has to be pushed back a 36 00:01:33,740 --> 00:01:29,880 week here it's just fine because 37 00:01:37,100 --> 00:01:33,750 election is actually on November 8th on 38 00:01:39,050 --> 00:01:37,110 December 6 the talk is to be a to be 39 00:01:41,450 --> 00:01:39,060 decided upon but the speaker is 40 00:01:42,740 --> 00:01:41,460 Christine Chen who will be giving she's 41 00:01:45,469 --> 00:01:42,750 given a talk here before she does 42 00:01:48,249 --> 00:01:45,479 wonderful talks she just hasn't told me 43 00:01:52,010 --> 00:01:48,259 what she's going to talk about this time 44 00:01:53,539 --> 00:01:52,020 hahaha or one of our one of our one of 45 00:01:55,399 --> 00:01:53,549 the campaign surrogates can go and give 46 00:01:57,859 --> 00:01:55,409 the November first talk I'm sure this is 47 00:01:59,630 --> 00:01:57,869 a very coveted audience yeah Maryland it 48 00:02:07,069 --> 00:01:59,640 Maryland is a state that could go either 49 00:02:08,900 --> 00:02:07,079 way right all right construction update 50 00:02:12,559 --> 00:02:08,910 and there really is an update this month 51 00:02:13,730 --> 00:02:12,569 okay it has been closed this is phase 1 52 00:02:17,480 --> 00:02:13,740 has been closed since 53 00:02:20,690 --> 00:02:17,490 of 2016 however next week 54 00:02:22,550 --> 00:02:20,700 phase two and phase three at the north 55 00:02:25,820 --> 00:02:22,560 and south ends the project will begin on 56 00:02:27,800 --> 00:02:25,830 Monday September 12th okay so this is 57 00:02:29,360 --> 00:02:27,810 the last public lecture series of this 58 00:02:31,520 --> 00:02:29,370 year that you could approach from the 59 00:02:33,890 --> 00:02:31,530 north you'll now have to approach from 60 00:02:37,220 --> 00:02:33,900 the south let me show you the map okay 61 00:02:39,530 --> 00:02:37,230 so you see this blue area here this is 62 00:02:41,180 --> 00:02:39,540 what's currently under construction that 63 00:02:45,890 --> 00:02:41,190 will stop being under construction 64 00:02:49,280 --> 00:02:45,900 as of next Monday okay then the part in 65 00:02:51,350 --> 00:02:49,290 red up here from our building here up to 66 00:02:54,410 --> 00:02:51,360 the north up up to University Parkway 67 00:02:56,630 --> 00:02:54,420 and down here in yellow along Wyman Park 68 00:03:00,860 --> 00:02:56,640 Drive those will be closed from 69 00:03:02,990 --> 00:03:00,870 September to December okay so next month 70 00:03:03,560 --> 00:03:03,000 in October when you come to the lecture 71 00:03:07,730 --> 00:03:03,570 series 72 00:03:10,010 --> 00:03:07,740 you must come via the South Gate into 73 00:03:12,800 --> 00:03:10,020 johns hopkins come up Weinman park drive 74 00:03:14,990 --> 00:03:12,810 to get to us here you cannot approach by 75 00:03:16,940 --> 00:03:15,000 a University Parkway this will all be 76 00:03:20,420 --> 00:03:16,950 closed through tool for the rest of this 77 00:03:25,460 --> 00:03:20,430 year okay if you need to know more about 78 00:03:27,140 --> 00:03:25,470 it here is the website I don't know have 79 00:03:29,060 --> 00:03:27,150 a way to memorize that just look for the 80 00:03:32,750 --> 00:03:29,070 San Martin project on the Johns Hopkins 81 00:03:34,850 --> 00:03:32,760 University website okay so next month 82 00:03:38,230 --> 00:03:34,860 north of st 2sc i will be closed 83 00:03:40,850 --> 00:03:38,240 approach STScI from the south all right 84 00:03:44,510 --> 00:03:40,860 hopefully I will see you all here next 85 00:03:47,540 --> 00:03:44,520 next month and you won't get lost our 86 00:03:51,140 --> 00:03:47,550 website if you need to check on things 87 00:03:53,660 --> 00:03:51,150 we have you can do our Hubbell site go 88 00:03:55,310 --> 00:03:53,670 tox link or just use your favorite 89 00:03:57,920 --> 00:03:55,320 search engine look for Hubble public 90 00:04:01,100 --> 00:03:57,930 talks you'll find this you have a list 91 00:04:03,770 --> 00:04:01,110 of the upcoming lectures you can watch 92 00:04:05,450 --> 00:04:03,780 the links to the live online webcasting 93 00:04:07,850 --> 00:04:05,460 from both on YouTube and SD s CI 94 00:04:11,390 --> 00:04:07,860 webcasting you can watch our past 95 00:04:13,100 --> 00:04:11,400 lectures all the way back to 2005 these 96 00:04:14,900 --> 00:04:13,110 wonderful folks have been webcasting it 97 00:04:17,120 --> 00:04:14,910 so there's lots of stuff and you can 98 00:04:19,370 --> 00:04:17,130 sign up for our public lecture series 99 00:04:21,650 --> 00:04:19,380 announcements a couple times a month we 100 00:04:23,720 --> 00:04:21,660 send out reminders of what's up and we 101 00:04:25,850 --> 00:04:23,730 tell you where the webcasts are posted 102 00:04:27,140 --> 00:04:25,860 if you want to see that a lecture that 103 00:04:29,659 --> 00:04:27,150 you missed 104 00:04:32,060 --> 00:04:29,669 um these are the announcements you can 105 00:04:34,010 --> 00:04:32,070 sign up at mail list at STScI to ddu 106 00:04:36,379 --> 00:04:34,020 it's easier to go to our web page 107 00:04:38,330 --> 00:04:36,389 actually we've gotten a ton of signups 108 00:04:41,300 --> 00:04:38,340 from our web page so that's probably the 109 00:04:43,340 --> 00:04:41,310 best thing to do if you need to if you 110 00:04:44,719 --> 00:04:43,350 would like to have a question i tom says 111 00:04:46,939 --> 00:04:44,729 something absolutely brilliant you want 112 00:04:50,210 --> 00:04:46,949 to ask him another question send it to 113 00:04:52,249 --> 00:04:50,220 public lecture at STScI to edu give us 114 00:04:53,659 --> 00:04:52,259 your comment and yet another way you 115 00:04:57,230 --> 00:04:53,669 could even sign up for the announcements 116 00:04:59,990 --> 00:04:57,240 alright on social media Hubble has 117 00:05:02,659 --> 00:05:00,000 Facebook to Twitter accounts it's on 118 00:05:04,159 --> 00:05:02,669 Google+ it's on Pinterest and maybe on a 119 00:05:07,490 --> 00:05:04,169 couple other places that I don't know 120 00:05:10,460 --> 00:05:07,500 about I myself am on Facebook Google+ 121 00:05:13,010 --> 00:05:10,470 and Twitter when I have time I don't do 122 00:05:16,279 --> 00:05:13,020 a heck of a lot of social media but I 123 00:05:18,860 --> 00:05:16,289 try to do a couple times a week uh there 124 00:05:21,409 --> 00:05:18,870 will not be an observatory tonight it 125 00:05:22,969 --> 00:05:21,419 probably is clear enough but the person 126 00:05:25,909 --> 00:05:22,979 running the observatory technician is 127 00:05:28,010 --> 00:05:25,919 out of town at the time okay so you will 128 00:05:30,260 --> 00:05:28,020 not have a Observatory but for those of 129 00:05:32,360 --> 00:05:30,270 you who are new usually after the 130 00:05:34,400 --> 00:05:32,370 lecture someone from the Maryland Space 131 00:05:35,570 --> 00:05:34,410 Grant observatory comes and will take 132 00:05:38,930 --> 00:05:35,580 you across the street to do some 133 00:05:42,640 --> 00:05:38,940 observing they do have a website MD 134 00:05:45,830 --> 00:05:42,650 space grant o RG and I believe they do 135 00:05:47,960 --> 00:05:45,840 open nights at the telescope every 136 00:05:49,550 --> 00:05:47,970 mostly every Friday okay so check their 137 00:05:51,080 --> 00:05:49,560 website to find out when their next 138 00:05:52,750 --> 00:05:51,090 observing session is because 139 00:05:56,089 --> 00:05:52,760 unfortunately we won't have it tonight 140 00:05:59,110 --> 00:05:56,099 okay now my favorite part of the night 141 00:06:03,680 --> 00:05:59,120 news from the universe for September 142 00:06:07,790 --> 00:06:03,690 2016 now everybody knows that August is 143 00:06:11,060 --> 00:06:07,800 a slow news month right not this month 144 00:06:12,860 --> 00:06:11,070 not for astronomy we had so much that I 145 00:06:14,659 --> 00:06:12,870 actually had to cut down so there's a 146 00:06:16,969 --> 00:06:14,669 bunch of cool news that I'm not going to 147 00:06:18,379 --> 00:06:16,979 get to tonight okay so let me just go 148 00:06:21,860 --> 00:06:18,389 through what I do have relatively 149 00:06:25,879 --> 00:06:21,870 quickly my top story or I guess I should 150 00:06:29,540 --> 00:06:25,889 say my top nan story is from curious to 151 00:06:32,029 --> 00:06:29,550 spurious I am talking about a something 152 00:06:34,250 --> 00:06:32,039 I noticed on Saturday August 27th an 153 00:06:38,570 --> 00:06:34,260 interesting set it SETI candidate in 154 00:06:40,760 --> 00:06:38,580 Hercules this was on a I noticed this on 155 00:06:42,950 --> 00:06:40,770 social media and that was 156 00:06:46,040 --> 00:06:42,960 to comment that there was a signal in 157 00:06:49,790 --> 00:06:46,050 the direction of the star HD 164 five 158 00:06:53,119 --> 00:06:49,800 nine five and that star is known to have 159 00:06:55,430 --> 00:06:53,129 an extrasolar planet around it okay and 160 00:06:58,219 --> 00:06:55,440 it came from the Ratan 600 radio 161 00:07:03,860 --> 00:06:58,229 telescope in some unpronounceable place 162 00:07:07,279 --> 00:07:03,870 in Russia okay um and so here is the 163 00:07:09,469 --> 00:07:07,289 signal that was published that you can 164 00:07:13,279 --> 00:07:09,479 see that the pink line is the actual 165 00:07:17,089 --> 00:07:13,289 signal and the green line is a fit for a 166 00:07:21,469 --> 00:07:17,099 point source located in the position of 167 00:07:23,899 --> 00:07:21,479 HD one six four five nine five so the 168 00:07:26,809 --> 00:07:23,909 conclusion of this article was not that 169 00:07:30,469 --> 00:07:26,819 oh my god we found aliens but it was 170 00:07:34,089 --> 00:07:30,479 rather softly stated the signal is 171 00:07:38,450 --> 00:07:34,099 interesting and merits further scrutiny 172 00:07:42,439 --> 00:07:38,460 however once the internet gets hold of 173 00:07:43,510 --> 00:07:42,449 it what do we get we get this SETI is 174 00:07:45,350 --> 00:07:43,520 investigating a possible 175 00:07:48,469 --> 00:07:45,360 extraterrestrial signal from deep space 176 00:07:52,249 --> 00:07:48,479 a strong signal that may originate from 177 00:07:57,110 --> 00:07:52,259 a sun-like star aliens sunlight being 178 00:07:59,170 --> 00:07:57,120 verified by SETI now okay so and it got 179 00:08:01,850 --> 00:07:59,180 off into all sorts of interesting 180 00:08:03,589 --> 00:08:01,860 conversations about extraterrestrial 181 00:08:05,540 --> 00:08:03,599 civilizations that have built a Dyson 182 00:08:08,029 --> 00:08:05,550 Sphere around their star and are 183 00:08:10,159 --> 00:08:08,039 capturing all the light from That star 184 00:08:12,080 --> 00:08:10,169 and for some reason then beaming all 185 00:08:13,969 --> 00:08:12,090 that energy right back out into space 186 00:08:17,089 --> 00:08:13,979 I'm not sure exactly why you would do 187 00:08:19,790 --> 00:08:17,099 that um I got home Monday night and my 188 00:08:22,969 --> 00:08:19,800 wife started telling me about an 189 00:08:25,399 --> 00:08:22,979 astronomy discovery my friends on 190 00:08:26,990 --> 00:08:25,409 Facebook my high school friends who I'm 191 00:08:28,309 --> 00:08:27,000 friends with on Facebook they always 192 00:08:29,330 --> 00:08:28,319 start to tag me whenever they see 193 00:08:32,690 --> 00:08:29,340 something interesting say Frank 194 00:08:35,029 --> 00:08:32,700 explained and explained so I had to kick 195 00:08:36,740 --> 00:08:35,039 in and I put up something a little less 196 00:08:38,480 --> 00:08:36,750 glamorous that said something like a 197 00:08:41,690 --> 00:08:38,490 single worth investigating but it's 198 00:08:43,159 --> 00:08:41,700 probably not aliens I wrote about ten or 199 00:08:45,079 --> 00:08:43,169 twelve paragraphs about it on my 200 00:08:46,340 --> 00:08:45,089 Facebook page so that I get explained to 201 00:08:48,310 --> 00:08:46,350 people well you know here's what's 202 00:08:51,980 --> 00:08:48,320 really going on 203 00:08:53,240 --> 00:08:51,990 meanwhile the folks who are actually 204 00:08:54,410 --> 00:08:53,250 going to follow up this investigation 205 00:08:57,949 --> 00:08:54,420 we're due 206 00:09:00,860 --> 00:08:57,959 to follow up this is the SETI folks here 207 00:09:02,540 --> 00:09:00,870 in the United States and this is their 208 00:09:05,389 --> 00:09:02,550 webpage that they put up to talk about 209 00:09:06,710 --> 00:09:05,399 this solar system 94 light-years away as 210 00:09:09,440 --> 00:09:06,720 a possible candidate 211 00:09:12,290 --> 00:09:09,450 well they immediately started turning 212 00:09:14,449 --> 00:09:12,300 their telescopes on to this star looking 213 00:09:17,030 --> 00:09:14,459 for something and they had ten times 214 00:09:19,100 --> 00:09:17,040 better sensitivity and they didn't find 215 00:09:23,780 --> 00:09:19,110 anything so they were pretty doubtful 216 00:09:25,460 --> 00:09:23,790 and then two days later on August 31st a 217 00:09:28,220 --> 00:09:25,470 press release came out from the Russian 218 00:09:29,960 --> 00:09:28,230 news agency Tass that said an additional 219 00:09:32,269 --> 00:09:29,970 check showed that it was emanating from 220 00:09:36,550 --> 00:09:32,279 a Soviet military satellite which had 221 00:09:40,160 --> 00:09:36,560 not be entered into any of the catalogs 222 00:09:41,870 --> 00:09:40,170 now we look at this we say Oh everyone's 223 00:09:42,379 --> 00:09:41,880 yo-yo everyone's making a big fuss over 224 00:09:46,389 --> 00:09:42,389 nothing 225 00:09:48,259 --> 00:09:46,399 um but this is how science is done okay 226 00:09:50,120 --> 00:09:48,269 astronomers who find something 227 00:09:52,579 --> 00:09:50,130 interesting and don't have enough 228 00:09:55,040 --> 00:09:52,589 sensitivity to really check it out tell 229 00:09:56,509 --> 00:09:55,050 others about it and then those go in and 230 00:09:58,310 --> 00:09:56,519 check it and see mmm and they 231 00:09:59,870 --> 00:09:58,320 cross-check it it has to be observed by 232 00:10:01,519 --> 00:09:59,880 multiple people using multiple 233 00:10:03,920 --> 00:10:01,529 instruments in order for people to 234 00:10:05,960 --> 00:10:03,930 really take it seriously so the science 235 00:10:07,880 --> 00:10:05,970 was done right because they said look 236 00:10:08,930 --> 00:10:07,890 we're not claiming extraterrestrials 237 00:10:09,470 --> 00:10:08,940 here we're just saying this is 238 00:10:11,780 --> 00:10:09,480 interesting 239 00:10:14,389 --> 00:10:11,790 somebody please follow up and the follow 240 00:10:17,180 --> 00:10:14,399 ups showed you oh sorry it isn't 241 00:10:21,170 --> 00:10:17,190 actually interesting okay however in the 242 00:10:24,250 --> 00:10:21,180 Internet age we have a moral to to go by 243 00:10:26,840 --> 00:10:24,260 here and the moral of the story is 244 00:10:29,900 --> 00:10:26,850 scientists must strive not to cry wolf 245 00:10:35,780 --> 00:10:29,910 because that's the job of the internet 246 00:10:38,360 --> 00:10:35,790 okay all right our second story we're 247 00:10:40,880 --> 00:10:38,370 doing to do some interplanetary mission 248 00:10:44,389 --> 00:10:40,890 updates the first update comes from the 249 00:10:46,490 --> 00:10:44,399 Juno mission to Jupiter and if you're 250 00:10:48,500 --> 00:10:46,500 here in July I told you about the Juno 251 00:10:50,900 --> 00:10:48,510 mission inserting itself into orbit 252 00:10:52,730 --> 00:10:50,910 around Jupiter the beginning of the Juno 253 00:10:54,559 --> 00:10:52,740 mission and the fact that it's going to 254 00:10:56,240 --> 00:10:54,569 go into this very tight orbit and go 255 00:10:58,269 --> 00:10:56,250 very far away and it's going to sample 256 00:11:01,939 --> 00:10:58,279 the full range of the magnetic field 257 00:11:04,840 --> 00:11:01,949 well it's on a very long orbit initially 258 00:11:08,360 --> 00:11:04,850 and it just got back for its first pass 259 00:11:10,850 --> 00:11:08,370 so in July 2016 is the insertion 260 00:11:12,710 --> 00:11:10,860 it's going to do two orbits with 53 and 261 00:11:15,200 --> 00:11:12,720 a half day period then it's going to 262 00:11:18,350 --> 00:11:15,210 follow that by 35 orbits with a 14-day 263 00:11:21,260 --> 00:11:18,360 period so on August 27th it made its 264 00:11:24,230 --> 00:11:21,270 first fly by of Jupiter and this image 265 00:11:27,230 --> 00:11:24,240 right here is as it's approaching for 266 00:11:28,730 --> 00:11:27,240 its first flyby okay and what we're 267 00:11:31,730 --> 00:11:28,740 going to get at least in the visible 268 00:11:35,060 --> 00:11:31,740 light images come from a camera called 269 00:11:37,579 --> 00:11:35,070 Juno cam and Juno cam is not a science 270 00:11:39,920 --> 00:11:37,589 camera all right I want to dent lesson 271 00:11:41,750 --> 00:11:39,930 your expectations here because it is an 272 00:11:43,880 --> 00:11:41,760 outreach camera it's just a 2 megapixel 273 00:11:45,829 --> 00:11:43,890 it's like a webcam sitting on the 274 00:11:48,110 --> 00:11:45,839 science a satellite ok it's going to get 275 00:11:50,690 --> 00:11:48,120 some cool pictures but it's not a 276 00:11:53,090 --> 00:11:50,700 science a real science deep science 277 00:11:54,860 --> 00:11:53,100 based eyes camera most of the science 278 00:11:56,390 --> 00:11:54,870 going to be done from Juno is about on 279 00:11:57,980 --> 00:11:56,400 the atmosphere and the magnetosphere 280 00:11:59,930 --> 00:11:57,990 it's going to have some ultraviolet 281 00:12:01,190 --> 00:11:59,940 imaging and some infrared imaging and 282 00:12:03,410 --> 00:12:01,200 it's going to look at the Aurora and 283 00:12:06,260 --> 00:12:03,420 such but the visible light images from 284 00:12:08,360 --> 00:12:06,270 Juno they aren't the highlight they are 285 00:12:11,140 --> 00:12:08,370 at the science goal of the mission ok 286 00:12:14,510 --> 00:12:11,150 but it did get some cool pictures 287 00:12:17,180 --> 00:12:14,520 because we have not studied the poles of 288 00:12:19,930 --> 00:12:17,190 Jupiter very very much the last time we 289 00:12:25,100 --> 00:12:19,940 saw the North Pole of Jupiter was in 290 00:12:27,590 --> 00:12:25,110 1974 well now we have these images okay 291 00:12:29,480 --> 00:12:27,600 so this is Jupiter's North Pole alright 292 00:12:31,040 --> 00:12:29,490 let me just go back to this one here you 293 00:12:32,480 --> 00:12:31,050 can see that most of Jupiter is this 294 00:12:34,490 --> 00:12:32,490 banded structure ok 295 00:12:36,620 --> 00:12:34,500 that's the stuff we're used to if we go 296 00:12:38,329 --> 00:12:36,630 look at the North Pole however you can 297 00:12:39,860 --> 00:12:38,339 start to see especially in this enhanced 298 00:12:42,260 --> 00:12:39,870 image that you've got all sorts of 299 00:12:45,140 --> 00:12:42,270 storminess going on in here you do not 300 00:12:47,390 --> 00:12:45,150 have that banded structure alright and 301 00:12:49,250 --> 00:12:47,400 what's really cool not just to see that 302 00:12:52,840 --> 00:12:49,260 the North Pole but they got this 303 00:12:55,310 --> 00:12:52,850 gorgeous picture of Jupiter's South Pole 304 00:12:57,920 --> 00:12:55,320 all right now can you see the amazing 305 00:12:59,630 --> 00:12:57,930 number of storms and there's still a 306 00:13:01,370 --> 00:12:59,640 little bit of banded nough stu the 307 00:13:02,900 --> 00:13:01,380 structure but there's a lot more 308 00:13:05,840 --> 00:13:02,910 turbulence going on 309 00:13:08,510 --> 00:13:05,850 there's slower speeds down here okay in 310 00:13:11,570 --> 00:13:08,520 a motion of it and so you can see that 311 00:13:14,570 --> 00:13:11,580 you've got an entire a different pattern 312 00:13:16,100 --> 00:13:14,580 on Jupiter at the poles than you do in 313 00:13:18,110 --> 00:13:16,110 that space star standard banded 314 00:13:20,210 --> 00:13:18,120 structure that runs around most of the 315 00:13:21,420 --> 00:13:20,220 planet so this is really cool because 316 00:13:23,820 --> 00:13:21,430 we've really not 317 00:13:25,980 --> 00:13:23,830 in the polls of Jupiter and we will get 318 00:13:28,920 --> 00:13:25,990 more of these as the mission continues 319 00:13:30,930 --> 00:13:28,930 okay but the next pass won't be until 320 00:13:33,660 --> 00:13:30,940 October at that time they're going to do 321 00:13:36,570 --> 00:13:33,670 a burn to go into the 14-day orbit so 322 00:13:39,540 --> 00:13:36,580 Juno has gone into it's serious science 323 00:13:41,460 --> 00:13:39,550 mode all right it's getting great great 324 00:13:43,650 --> 00:13:41,470 observations and we look forward to more 325 00:13:45,840 --> 00:13:43,660 cool pictures but really a lot more 326 00:13:49,590 --> 00:13:45,850 serious science about the atmosphere to 327 00:13:52,889 --> 00:13:49,600 come our second mission update is about 328 00:13:56,250 --> 00:13:52,899 Rosetta the Rosetta mission and the 329 00:13:58,530 --> 00:13:56,260 lander feel a now if you remember how 330 00:14:01,370 --> 00:13:58,540 many of you were you he we're coming to 331 00:14:05,570 --> 00:14:01,380 the public lecture series back in 2014 332 00:14:10,199 --> 00:14:05,580 okay do you remember November 2014 333 00:14:11,550 --> 00:14:10,209 because that's when we had a particular 334 00:14:13,740 --> 00:14:11,560 event now let me just go through his 335 00:14:16,590 --> 00:14:13,750 throw over this okay so the Rosetta 336 00:14:22,050 --> 00:14:16,600 mission its final goal was to comment 337 00:14:24,389 --> 00:14:22,060 67p churyumov-gerasimenko okay or just 338 00:14:29,160 --> 00:14:24,399 to make it easier we like to call it 339 00:14:32,220 --> 00:14:29,170 Comet rubber ducky simply because of its 340 00:14:35,640 --> 00:14:32,230 shape now so 67p was the target of it 341 00:14:40,829 --> 00:14:35,650 okay and the Rosetta main orbiter went 342 00:14:46,040 --> 00:14:40,839 into orbit around 67p the feel a lander 343 00:14:48,150 --> 00:14:46,050 was released in November 2014 to land on 344 00:14:51,480 --> 00:14:48,160 actually uh what would be the head of 345 00:14:54,630 --> 00:14:51,490 the duck okay and it dropped on down for 346 00:14:56,490 --> 00:14:54,640 seven hours and when it hit two harpoons 347 00:14:59,970 --> 00:14:56,500 were supposed to dig into the ice and 348 00:15:02,850 --> 00:14:59,980 hold it on well the harpoons didn't go 349 00:15:05,250 --> 00:15:02,860 so instead fillet bounced it bounced a 350 00:15:07,170 --> 00:15:05,260 kilometer upward okay 351 00:15:08,880 --> 00:15:07,180 relatively low gravity you know it could 352 00:15:12,480 --> 00:15:08,890 jump really high and actually did a 353 00:15:15,540 --> 00:15:12,490 second bounce and settled into a an 354 00:15:18,240 --> 00:15:15,550 unknown region on the surface of the 355 00:15:20,090 --> 00:15:18,250 comet it was obviously not pointed 356 00:15:22,800 --> 00:15:20,100 upward because it couldn't communicate 357 00:15:25,590 --> 00:15:22,810 it got they got a few pictures from it 358 00:15:27,840 --> 00:15:25,600 but they couldn't keep it alive and the 359 00:15:29,960 --> 00:15:27,850 feel a lander was declared a loss in 360 00:15:32,580 --> 00:15:29,970 March of 2016 361 00:15:34,650 --> 00:15:32,590 however they 362 00:15:36,870 --> 00:15:34,660 knew where it was and the rosetta 363 00:15:38,700 --> 00:15:36,880 mission main orbiter kept orbiting 364 00:15:40,800 --> 00:15:38,710 around it and actually moved into closer 365 00:15:43,820 --> 00:15:40,810 and closer orbits as the mission 366 00:15:49,110 --> 00:15:43,830 continued and they searched for it and 367 00:15:52,560 --> 00:15:49,120 just a few days ago they found it now 368 00:15:54,270 --> 00:15:52,570 can you spot the feel a lander those of 369 00:16:00,270 --> 00:15:54,280 you who know where it is yes it's 370 00:16:02,160 --> 00:16:00,280 actually over there all right let me 371 00:16:04,010 --> 00:16:02,170 give you the blow-up okay this is an 372 00:16:07,650 --> 00:16:04,020 amazing image by the way it's 5 373 00:16:09,870 --> 00:16:07,660 centimeters per pixel okay 5 centimeters 374 00:16:10,530 --> 00:16:09,880 per pixel amazing stuff of the surface 375 00:16:12,720 --> 00:16:10,540 of a comet 376 00:16:15,570 --> 00:16:12,730 here is the feel a lander they found it 377 00:16:17,340 --> 00:16:15,580 ok and you can see it's tipped over on 378 00:16:19,590 --> 00:16:17,350 its side so of course it's not going to 379 00:16:22,170 --> 00:16:19,600 have good communication with the with 380 00:16:24,420 --> 00:16:22,180 the orbiter all right and here is a 381 00:16:27,630 --> 00:16:24,430 diagram annotated diagram to help you 382 00:16:31,800 --> 00:16:27,640 understand that the there the legs of 383 00:16:34,400 --> 00:16:31,810 the lander on huh where's the ice the 384 00:16:37,530 --> 00:16:34,410 whole the whole comet is is ice and rock 385 00:16:39,120 --> 00:16:37,540 yes but if you know the the surface of a 386 00:16:42,420 --> 00:16:39,130 comet is generally a sort of a tar-like 387 00:16:45,390 --> 00:16:42,430 substance ok because the volatiles have 388 00:16:47,460 --> 00:16:45,400 have gone away all right this one this 389 00:16:50,130 --> 00:16:47,470 comment only gets into about 1.2 390 00:16:52,410 --> 00:16:50,140 astronomical units as closest approach 391 00:16:56,160 --> 00:16:52,420 to the Sun but still the volatiles will 392 00:16:57,960 --> 00:16:56,170 will go away you get inside 3a you then 393 00:17:01,560 --> 00:16:57,970 the volatiles on the surface will 394 00:17:03,330 --> 00:17:01,570 definitely definitely go away ok so it 395 00:17:06,510 --> 00:17:03,340 actually one of the reasons why the 396 00:17:08,220 --> 00:17:06,520 field a lander bounced was at the 397 00:17:11,699 --> 00:17:08,230 surface was was harder than they 398 00:17:13,110 --> 00:17:11,709 expected it to be okay based on pron 399 00:17:16,199 --> 00:17:13,120 previous things the deep impact they 400 00:17:17,550 --> 00:17:16,209 expected a softer surface alright so 401 00:17:19,860 --> 00:17:17,560 this is the feel a lander here 402 00:17:27,110 --> 00:17:19,870 unfortunately it's unrecoverable all 403 00:17:30,960 --> 00:17:27,120 right ah call Bruce Willis there you go 404 00:17:32,670 --> 00:17:30,970 alright so here's what I just I just 405 00:17:35,390 --> 00:17:32,680 want to recap for you the rosetta 406 00:17:39,450 --> 00:17:35,400 mission okay it was launched in March of 407 00:17:42,270 --> 00:17:39,460 2004 it had flybys of Earth three times 408 00:17:45,810 --> 00:17:42,280 it flew by Mars once it flew by two 409 00:17:48,230 --> 00:17:45,820 different asteroids it 410 00:17:51,150 --> 00:17:48,240 five dat 67p in August the feel a 411 00:17:54,840 --> 00:17:51,160 landing was in November 2014 412 00:17:56,400 --> 00:17:54,850 Rosetta stayed with 67p as it went came 413 00:17:59,850 --> 00:17:56,410 up approached the Sun went through 414 00:18:02,970 --> 00:17:59,860 perihelion last August and two years 415 00:18:05,100 --> 00:18:02,980 later now all right it's still with it 416 00:18:08,010 --> 00:18:05,110 and it's moved down to that very close 417 00:18:08,970 --> 00:18:08,020 orbit and the mission is finally going 418 00:18:12,810 --> 00:18:08,980 to end this month 419 00:18:15,120 --> 00:18:12,820 on September 30th they're going to take 420 00:18:18,060 --> 00:18:15,130 the main orbiter and have that also land 421 00:18:21,780 --> 00:18:18,070 on the comet now I say land in a general 422 00:18:25,410 --> 00:18:21,790 sense because as one one blog put it 423 00:18:27,420 --> 00:18:25,420 it'll be more like a soft crash because 424 00:18:29,880 --> 00:18:27,430 it doesn't have the kind of landing gear 425 00:18:33,030 --> 00:18:29,890 that filet was built with so it will 426 00:18:35,820 --> 00:18:33,040 effectively crash into 67p at the time 427 00:18:37,920 --> 00:18:35,830 and will continue to orbit with 67p for 428 00:18:40,470 --> 00:18:37,930 the rest of history alright so we can 429 00:18:41,910 --> 00:18:40,480 look for some really cool images from 430 00:18:44,220 --> 00:18:41,920 the Rosetta mission the end of this 431 00:18:46,050 --> 00:18:44,230 month on September 30th because as this 432 00:18:48,450 --> 00:18:46,060 main orbiter gets in close to the comet 433 00:18:50,400 --> 00:18:48,460 it's got a lot more science instruments 434 00:18:52,710 --> 00:18:50,410 that it can take all sorts of cool 435 00:18:55,440 --> 00:18:52,720 readings and get a lot of interesting 436 00:18:59,250 --> 00:18:55,450 science as it comes in for landing the 437 00:19:01,530 --> 00:18:59,260 end of this month okay alright I had to 438 00:19:03,060 --> 00:19:01,540 throw in one Hubble story I'm sorry Tom 439 00:19:05,250 --> 00:19:03,070 I'm taking so long but I had to throw it 440 00:19:07,350 --> 00:19:05,260 once one Hubble story because the rest 441 00:19:09,540 --> 00:19:07,360 of the stuff was from from elsewhere and 442 00:19:13,080 --> 00:19:09,550 our final story tonight is galaxies late 443 00:19:15,930 --> 00:19:13,090 bloomers okay so Hubble release these 444 00:19:20,730 --> 00:19:15,940 two cool images of this this month of 445 00:19:23,970 --> 00:19:20,740 Pisces a and Pisces B two dwarf galaxies 446 00:19:25,890 --> 00:19:23,980 alright and what's one of the really 447 00:19:28,620 --> 00:19:25,900 cool things was how these galaxies were 448 00:19:30,030 --> 00:19:28,630 discovered so when I say galaxies you 449 00:19:32,040 --> 00:19:30,040 probably think of something like the 450 00:19:36,560 --> 00:19:32,050 Whirlpool Galaxy sort of the standard 451 00:19:39,570 --> 00:19:36,570 big giant spiral galaxies okay but the 452 00:19:41,610 --> 00:19:39,580 Whirlpool Galaxy is actually bigger than 453 00:19:44,280 --> 00:19:41,620 you think because this is the visible 454 00:19:46,020 --> 00:19:44,290 light view if we go into the radio and 455 00:19:49,950 --> 00:19:46,030 search for the hydrogen gas the 456 00:19:53,460 --> 00:19:49,960 Whirlpool Galaxy looks like that there 457 00:19:55,980 --> 00:19:53,470 is a lot more hydrogen gas up there that 458 00:19:58,920 --> 00:19:55,990 we can see in radio than can be seen in 459 00:20:02,010 --> 00:19:58,930 the visible eye of stars so these 460 00:20:04,950 --> 00:20:02,020 or galaxies here were actually found in 461 00:20:07,800 --> 00:20:04,960 by radio searches looking for blobs of 462 00:20:09,780 --> 00:20:07,810 hydrogen it was actually a survey of the 463 00:20:13,410 --> 00:20:09,790 Milky Way galaxy looking for hydrogen 464 00:20:15,480 --> 00:20:13,420 clouds and they found 30 to 50 465 00:20:18,090 --> 00:20:15,490 candidates that might actually be 466 00:20:20,100 --> 00:20:18,100 external galaxies they went through and 467 00:20:22,620 --> 00:20:20,110 they narrowed them down to the top 10 or 468 00:20:24,540 --> 00:20:22,630 12 and they chose two of them that had 469 00:20:26,400 --> 00:20:24,550 the highest probability of actually 470 00:20:28,470 --> 00:20:26,410 being galaxies they didn't know they 471 00:20:30,120 --> 00:20:28,480 couldn't see the stars in these galaxies 472 00:20:32,340 --> 00:20:30,130 they could just see there was a blob of 473 00:20:35,190 --> 00:20:32,350 hydrogen there and when they looked with 474 00:20:37,950 --> 00:20:35,200 Hubble they found the two dwarf galaxies 475 00:20:40,260 --> 00:20:37,960 and with Hubble being able to resolve 476 00:20:43,050 --> 00:20:40,270 the stars and be able to do the stellar 477 00:20:45,600 --> 00:20:43,060 populations of it they were actually 478 00:20:49,140 --> 00:20:45,610 able to tell that these these dwarf 479 00:20:51,540 --> 00:20:49,150 galaxies are late bloomers they had a 480 00:20:53,850 --> 00:20:51,550 burst of star formation only a hundred 481 00:20:56,820 --> 00:20:53,860 million years ago all right now I know 482 00:20:59,280 --> 00:20:56,830 100 million years is really long to you 483 00:21:02,940 --> 00:20:59,290 and me but in terms of the cosmos that's 484 00:21:06,420 --> 00:21:02,950 13.8 billion years old 100 million years 485 00:21:09,540 --> 00:21:06,430 ago is way late in universe to have such 486 00:21:11,880 --> 00:21:09,550 a burst of star formation okay so these 487 00:21:13,560 --> 00:21:11,890 are galaxies that have been hanging out 488 00:21:16,260 --> 00:21:13,570 in what we call in what we call a void 489 00:21:18,720 --> 00:21:16,270 region of the universe they're very very 490 00:21:21,090 --> 00:21:18,730 slow developers they're late developers 491 00:21:23,130 --> 00:21:21,100 and only in the last hundred million 492 00:21:25,580 --> 00:21:23,140 years have they had a burst a 493 00:21:29,430 --> 00:21:25,590 significant amount of star formation 494 00:21:31,920 --> 00:21:29,440 okay so by using the radio to then 495 00:21:36,060 --> 00:21:31,930 follow up with optical we can actually 496 00:21:40,170 --> 00:21:36,070 find these rare small galaxies out in 497 00:21:41,940 --> 00:21:40,180 universe okay they're in the direction 498 00:21:43,680 --> 00:21:41,950 of Pisces they're not in the local group 499 00:21:45,720 --> 00:21:43,690 okay there's they're far enough away 500 00:21:48,840 --> 00:21:45,730 that that they're there they're outside 501 00:21:51,810 --> 00:21:48,850 the local group okay all right we got to 502 00:21:55,890 --> 00:21:51,820 get to our featured speaker all right 503 00:21:58,830 --> 00:21:55,900 let me switch over and our speaker 504 00:22:01,050 --> 00:21:58,840 tonight is Tom Brown and I want to thank 505 00:22:02,850 --> 00:22:01,060 him for postponing his talk from May so 506 00:22:05,490 --> 00:22:02,860 I could bring in sandy Faber back then 507 00:22:07,710 --> 00:22:05,500 and I know you guys enjoyed her talk 508 00:22:10,140 --> 00:22:07,720 you're definitely gonna enjoy Tom Tom 509 00:22:12,160 --> 00:22:10,150 got his degree across the street at 510 00:22:14,590 --> 00:22:12,170 Johns Hopkins University 511 00:22:16,810 --> 00:22:14,600 he did hippo stock down in Goddard Space 512 00:22:19,600 --> 00:22:16,820 Flight Center and then he came to work 513 00:22:22,660 --> 00:22:19,610 here at Space Telescope a very Maryland 514 00:22:25,570 --> 00:22:22,670 career here at Space Telescope he's done 515 00:22:27,130 --> 00:22:25,580 some amazing things he's worked on the 516 00:22:29,980 --> 00:22:27,140 Hubble Space Telescope he's worked on 517 00:22:33,070 --> 00:22:29,990 the James Webb Space Telescope and he is 518 00:22:36,730 --> 00:22:33,080 now the head of the Hubble mission here 519 00:22:39,039 --> 00:22:36,740 and he is a famous in astronomy circles 520 00:22:43,510 --> 00:22:39,049 for having taken the deepest visible 521 00:22:44,980 --> 00:22:43,520 light image ever of a star field in the 522 00:22:47,860 --> 00:22:44,990 andromeda galaxy 523 00:22:51,310 --> 00:22:47,870 we call it the stellar deep field and it 524 00:22:56,140 --> 00:22:51,320 was recently honored by being on the 525 00:22:59,049 --> 00:22:56,150 cover of david bowie's last album so a 526 00:23:07,390 --> 00:22:59,059 true true famous guy ladies and 527 00:23:08,770 --> 00:23:07,400 gentlemen Tom Brown all right thank you 528 00:23:09,640 --> 00:23:08,780 Frank thanks for that introduction can 529 00:23:11,409 --> 00:23:09,650 everyone hear me all right with the 530 00:23:12,820 --> 00:23:11,419 microphone all right and another thing 531 00:23:14,919 --> 00:23:12,830 you got to remind me now and then is I'm 532 00:23:16,299 --> 00:23:14,929 both a little hyperactive and I'm from 533 00:23:17,560 --> 00:23:16,309 New York so you got to slow me down now 534 00:23:20,140 --> 00:23:17,570 and then if I start going too quickly 535 00:23:22,180 --> 00:23:20,150 okay so again as Frank said I'll be 536 00:23:23,409 --> 00:23:22,190 talking today about the missing galaxies 537 00:23:25,120 --> 00:23:23,419 and the nearby universe this is 538 00:23:26,650 --> 00:23:25,130 something known as the missing satellite 539 00:23:28,390 --> 00:23:26,660 problem that astronomers have been 540 00:23:29,860 --> 00:23:28,400 studying for decades and one way to 541 00:23:32,860 --> 00:23:29,870 attack this problem is by looking at the 542 00:23:34,870 --> 00:23:32,870 oldest stars in the nearby universe so 543 00:23:36,460 --> 00:23:34,880 this is work I'm doing with the Hubble 544 00:23:37,900 --> 00:23:36,470 Space Telescope it's a program I put 545 00:23:40,539 --> 00:23:37,910 together a few years ago it was about 546 00:23:42,460 --> 00:23:40,549 113 orbits on Hubble and the team of 547 00:23:44,110 --> 00:23:42,470 folks I show here from around the world 548 00:23:45,669 --> 00:23:44,120 worked on it with me I've listed their 549 00:23:47,049 --> 00:23:45,679 names I won't go through them all but 550 00:23:48,700 --> 00:23:47,059 some of them are observers on Hubble 551 00:23:50,200 --> 00:23:48,710 like myself there's some folks here who 552 00:23:52,240 --> 00:23:50,210 had time on the Keck telescope in Hawaii 553 00:23:53,919 --> 00:23:52,250 and then there are also some theorists 554 00:23:56,080 --> 00:23:53,929 on this program who study both the 555 00:23:57,430 --> 00:23:56,090 evolution of galaxies and time the 556 00:23:59,140 --> 00:23:57,440 evolution of the universe and the 557 00:24:00,430 --> 00:23:59,150 evolution of stars so it's a good mix of 558 00:24:04,930 --> 00:24:00,440 people who use telescopes on the ground 559 00:24:06,669 --> 00:24:04,940 in space and then also theorists so this 560 00:24:08,860 --> 00:24:06,679 is a simulation from been more 561 00:24:10,840 --> 00:24:08,870 universities Uruk of how the structure 562 00:24:12,549 --> 00:24:10,850 of the universe evolved with time on the 563 00:24:14,169 --> 00:24:12,559 right hand side here so this little 564 00:24:15,250 --> 00:24:14,179 number cutting down here is red ship to 565 00:24:16,810 --> 00:24:15,260 those who are familiar with it so this 566 00:24:18,130 --> 00:24:16,820 is red shift going into the present and 567 00:24:20,380 --> 00:24:18,140 the beginning of the simulation I'll 568 00:24:21,580 --> 00:24:20,390 back up here when it stops so you can 569 00:24:24,100 --> 00:24:21,590 see it again the begin the simulation 570 00:24:25,660 --> 00:24:24,110 starts right after the Big Bang and then 571 00:24:27,640 --> 00:24:25,670 the matter in the universe call 572 00:24:30,040 --> 00:24:27,650 les is in this filamentary structure you 573 00:24:32,230 --> 00:24:30,050 see here this is how theorists predict 574 00:24:34,030 --> 00:24:32,240 the universe evolved under the paradigm 575 00:24:35,200 --> 00:24:34,040 of cold dark matter and the assumption 576 00:24:37,270 --> 00:24:35,210 here is that there is dark matter 577 00:24:37,750 --> 00:24:37,280 permeating the universe it's cold and 578 00:24:42,370 --> 00:24:37,760 dark 579 00:24:44,380 --> 00:24:42,380 and you can't see it but you do see are 580 00:24:45,700 --> 00:24:44,390 the galaxies that form in the filaments 581 00:24:48,670 --> 00:24:45,710 along the structure of cold dark matter 582 00:24:51,220 --> 00:24:48,680 so dark matter is the scaffolding upon 583 00:24:52,480 --> 00:24:51,230 which galaxies are built so the dark 584 00:24:53,710 --> 00:24:52,490 matter permeates the universe and then 585 00:24:55,540 --> 00:24:53,720 these filaments are where you have large 586 00:24:57,700 --> 00:24:55,550 galaxies so these bright red points here 587 00:24:59,110 --> 00:24:57,710 are galaxies like the Milky Way giant 588 00:25:00,790 --> 00:24:59,120 spiral galaxies are giant elliptical 589 00:25:04,690 --> 00:25:00,800 galaxies and the little tiny dots are 590 00:25:07,420 --> 00:25:04,700 satellite galaxies the cold egg matter 591 00:25:08,800 --> 00:25:07,430 theory confirm conforms with a lot of 592 00:25:11,470 --> 00:25:08,810 the observable phenomena in the universe 593 00:25:13,510 --> 00:25:11,480 but one thing it strikes out on is it 594 00:25:15,190 --> 00:25:13,520 over predicts the number of tiny little 595 00:25:17,040 --> 00:25:15,200 galaxies so that's Ana long-standing 596 00:25:19,960 --> 00:25:17,050 problem with the cold dark matter theory 597 00:25:21,910 --> 00:25:19,970 so here's a zoom in of an environment 598 00:25:23,650 --> 00:25:21,920 like our own Milky Way this is from my 599 00:25:25,630 --> 00:25:23,660 collaborator Jason Tomlinson who also 600 00:25:28,000 --> 00:25:25,640 works here at the Institute he's a 601 00:25:29,680 --> 00:25:28,010 theorist and observer and the simulation 602 00:25:31,750 --> 00:25:29,690 I'm showing here is about a million 603 00:25:33,430 --> 00:25:31,760 light years on aside and so this is the 604 00:25:35,410 --> 00:25:33,440 environment around a galaxy like our own 605 00:25:37,480 --> 00:25:35,420 Milky Way and this shows in his 606 00:25:39,310 --> 00:25:37,490 simulation here in Jason simulation the 607 00:25:41,080 --> 00:25:39,320 expectations for the distribution of 608 00:25:42,430 --> 00:25:41,090 dark matter in the nearby universe the 609 00:25:43,570 --> 00:25:42,440 very nearby universe within a million 610 00:25:45,820 --> 00:25:43,580 light years I might not sound that 611 00:25:47,380 --> 00:25:45,830 nearby but this is roughly the the 612 00:25:48,550 --> 00:25:47,390 sphere of influence of the Milky Way 613 00:25:50,290 --> 00:25:48,560 so the Milky Way would be sitting here 614 00:25:52,480 --> 00:25:50,300 at the center and we know there's a 615 00:25:53,710 --> 00:25:52,490 galaxy there it's the Milky Way and then 616 00:25:55,810 --> 00:25:53,720 there's all these little clumps of dark 617 00:25:57,820 --> 00:25:55,820 matter orbiting the gravitational well 618 00:26:00,220 --> 00:25:57,830 of the Milky Way and there are hundreds 619 00:26:01,600 --> 00:26:00,230 of them in this simulation and when you 620 00:26:02,740 --> 00:26:01,610 look at the number of galaxies actually 621 00:26:05,380 --> 00:26:02,750 orbiting the Milky Way there's only a 622 00:26:07,200 --> 00:26:05,390 few dozen so it's off by a large amount 623 00:26:09,730 --> 00:26:07,210 it's grossly off the number of observed 624 00:26:10,810 --> 00:26:09,740 satellite galaxies compared to the 625 00:26:13,030 --> 00:26:10,820 predictions of the cold dark matter 626 00:26:14,710 --> 00:26:13,040 theory so this is the missing satellite 627 00:26:16,000 --> 00:26:14,720 problem that call dark matter says 628 00:26:17,980 --> 00:26:16,010 there's lots of little clumps of dark 629 00:26:19,900 --> 00:26:17,990 matter out here and yet we only see a 630 00:26:21,730 --> 00:26:19,910 few dozen galaxies and these clumps to 631 00:26:23,500 --> 00:26:21,740 dark matter are the seeds of galaxy 632 00:26:25,120 --> 00:26:23,510 formation so this was a big shock when 633 00:26:27,730 --> 00:26:25,130 people started doing censuses of 634 00:26:28,990 --> 00:26:27,740 galaxies comparing them to theory and so 635 00:26:33,190 --> 00:26:29,000 things are off by more than an order of 636 00:26:34,540 --> 00:26:33,200 magnitude so that's it a summary theory 637 00:26:36,280 --> 00:26:34,550 predicts more dark matter clumps 638 00:26:38,020 --> 00:26:36,290 orbiting the Milky Way than the number 639 00:26:40,870 --> 00:26:38,030 of dwarf satellites we actually 640 00:26:43,390 --> 00:26:40,880 that's the missing satellite problem so 641 00:26:44,980 --> 00:26:43,400 a solution to this was proposed a while 642 00:26:47,500 --> 00:26:44,990 back and has to do with the realization 643 00:26:49,000 --> 00:26:47,510 of the universe so this is a cartoon I'm 644 00:26:50,980 --> 00:26:49,010 showing here with the big bang on the 645 00:26:52,390 --> 00:26:50,990 left and the modern era on the right and 646 00:26:54,130 --> 00:26:52,400 time is just progressing from left to 647 00:26:56,110 --> 00:26:54,140 right here in this cartoon this is the 648 00:26:58,720 --> 00:26:56,120 evolution of the universe so the Big 649 00:27:01,180 --> 00:26:58,730 Bang is right here right after the Big 650 00:27:03,250 --> 00:27:01,190 Bang there's a short pier here called 651 00:27:05,110 --> 00:27:03,260 the Dark Ages where the universe cooled 652 00:27:06,700 --> 00:27:05,120 enough to become neutral so you have 653 00:27:07,930 --> 00:27:06,710 hydrogen is neutral 654 00:27:10,480 --> 00:27:07,940 you just have electron orbiting the 655 00:27:13,480 --> 00:27:10,490 proton things have cooled down those 656 00:27:15,280 --> 00:27:13,490 stars have not yet come on then the 657 00:27:17,160 --> 00:27:15,290 first stars and galaxies are born right 658 00:27:19,090 --> 00:27:17,170 here shortly after the Big Bang and 659 00:27:20,590 --> 00:27:19,100 ironically what happens is when the 660 00:27:22,150 --> 00:27:20,600 first stars and galaxies come on they 661 00:27:24,370 --> 00:27:22,160 illuminate everything that actually 662 00:27:25,720 --> 00:27:24,380 snuffs out a lot of star formation all 663 00:27:27,070 --> 00:27:25,730 around the universe because that light 664 00:27:28,510 --> 00:27:27,080 comes on it's a very strong source of 665 00:27:30,130 --> 00:27:28,520 ultraviolet light and it blows out the 666 00:27:31,540 --> 00:27:30,140 gas out of a lot of little dark matter 667 00:27:33,550 --> 00:27:31,550 clumps and turns off the star formation 668 00:27:34,840 --> 00:27:33,560 that's the theory here so you have the 669 00:27:36,340 --> 00:27:34,850 first stars and galaxies come on they 670 00:27:37,840 --> 00:27:36,350 come on so rapidly they actually shut 671 00:27:40,330 --> 00:27:37,850 off the star formation in a lot of parts 672 00:27:42,100 --> 00:27:40,340 of the universe so this is the era of 673 00:27:43,900 --> 00:27:42,110 reionisation when the universe gets 674 00:27:47,260 --> 00:27:43,910 ionized from those first stars and 675 00:27:49,300 --> 00:27:47,270 galaxies forming then after that era is 676 00:27:51,160 --> 00:27:49,310 done galaxies continued evolve new stars 677 00:27:52,330 --> 00:27:51,170 are born from a rich enriched gas you've 678 00:27:54,100 --> 00:27:52,340 heard this before we're all made from 679 00:27:55,420 --> 00:27:54,110 star stuff so stars explode their 680 00:27:56,950 --> 00:27:55,430 material goes out into the interstellar 681 00:27:59,890 --> 00:27:56,960 medium new stars are born from that 682 00:28:01,870 --> 00:27:59,900 enriched gas and time goes on and here's 683 00:28:04,420 --> 00:28:01,880 when the Sun would be born at this point 684 00:28:05,440 --> 00:28:04,430 in history and here we are today so the 685 00:28:07,210 --> 00:28:05,450 Sun was born about four-and-a-half 686 00:28:08,380 --> 00:28:07,220 billion years ago here we are sitting 687 00:28:11,830 --> 00:28:08,390 here in the modern universe and we look 688 00:28:13,330 --> 00:28:11,840 back in time so now we return to Jason 689 00:28:15,070 --> 00:28:13,340 simulation so this is the Dark Matter 690 00:28:19,060 --> 00:28:15,080 distribution around a galaxy like our 691 00:28:21,010 --> 00:28:19,070 Milky Way and the theory goes he's 692 00:28:23,020 --> 00:28:21,020 highlighted here in green those are the 693 00:28:24,490 --> 00:28:23,030 satellite galaxies that formed lots of 694 00:28:26,410 --> 00:28:24,500 stars and that's why we know about them 695 00:28:28,540 --> 00:28:26,420 so for decades we've known about these 696 00:28:30,340 --> 00:28:28,550 satellite dwarf galaxies these clumps of 697 00:28:32,980 --> 00:28:30,350 dark matter were large enough to 698 00:28:34,930 --> 00:28:32,990 accumulate a bunch of gas have stars 699 00:28:36,970 --> 00:28:34,940 form and then they continued forming 700 00:28:39,490 --> 00:28:36,980 stars until the present era so these 701 00:28:40,990 --> 00:28:39,500 little clumps here all continued forming 702 00:28:42,430 --> 00:28:41,000 stars to the present day and this is 703 00:28:43,810 --> 00:28:42,440 what we knew about galaxies up until the 704 00:28:44,920 --> 00:28:43,820 stuff I'll show you tonight this is the 705 00:28:46,930 --> 00:28:44,930 assumption that's been made about all 706 00:28:49,030 --> 00:28:46,940 galaxies that galaxies are groups of 707 00:28:51,280 --> 00:28:49,040 stars built upon dark matter that have a 708 00:28:51,520 --> 00:28:51,290 wide range of Ages as stars born in the 709 00:28:53,080 --> 00:28:51,530 early 710 00:28:54,640 --> 00:28:53,090 University of Stars continuing to form 711 00:28:56,320 --> 00:28:54,650 up until today I mean Frank just showed 712 00:28:58,570 --> 00:28:56,330 this press release with these galaxies 713 00:29:01,090 --> 00:28:58,580 form stars very recently so until 714 00:29:02,850 --> 00:29:01,100 recently every single galaxy had not 715 00:29:06,460 --> 00:29:02,860 only old stars but younger stars as well 716 00:29:08,920 --> 00:29:06,470 what's that okay that's I thought maybe 717 00:29:10,840 --> 00:29:08,930 it was me sorry I thought I'd turn off 718 00:29:12,160 --> 00:29:10,850 my phone as a string okay so so anyway 719 00:29:14,620 --> 00:29:12,170 this is the theory this is the 720 00:29:16,360 --> 00:29:14,630 theoretical prediction for the kinds of 721 00:29:17,850 --> 00:29:16,370 galaxies we've known about forever for 722 00:29:19,840 --> 00:29:17,860 decades orbiting the Milky Way the 723 00:29:21,370 --> 00:29:19,850 problem is here you see that a lot of 724 00:29:22,840 --> 00:29:21,380 these little clumps of dark matter don't 725 00:29:24,550 --> 00:29:22,850 aren't highlighted they just stay dark 726 00:29:25,990 --> 00:29:24,560 this is what the theory predicts that 727 00:29:27,310 --> 00:29:26,000 most of this guy most of these Dark 728 00:29:28,150 --> 00:29:27,320 Matter clumps and never form stars and 729 00:29:29,920 --> 00:29:28,160 that's why you don't know they're there 730 00:29:31,630 --> 00:29:29,930 but they are there it's just clumps of 731 00:29:34,330 --> 00:29:31,640 dark matter orbiting the Milky Way if 732 00:29:36,430 --> 00:29:34,340 this is true here are these red ones 733 00:29:38,080 --> 00:29:36,440 I've highlighted there should be fossil 734 00:29:40,210 --> 00:29:38,090 galaxies out there that we didn't know 735 00:29:41,560 --> 00:29:40,220 about that are just ancient and are made 736 00:29:43,720 --> 00:29:41,570 from pristine gas the early universe 737 00:29:45,220 --> 00:29:43,730 form stars and then we're shut off by 738 00:29:47,290 --> 00:29:45,230 the realisation universe so these ones 739 00:29:48,580 --> 00:29:47,300 are on the cusp you have the galaxies 740 00:29:50,110 --> 00:29:48,590 that kept forming stars because they 741 00:29:52,210 --> 00:29:50,120 were big then you have these smaller 742 00:29:53,350 --> 00:29:52,220 guys that started to form stars in the 743 00:29:54,940 --> 00:29:53,360 early universe and then with the lights 744 00:29:56,740 --> 00:29:54,950 came on and they snuffed them out and 745 00:29:58,090 --> 00:29:56,750 they never formed stars again so these 746 00:30:00,310 --> 00:29:58,100 are ones a kind of like a transition 747 00:30:01,720 --> 00:30:00,320 between the galaxies that kept forming 748 00:30:04,780 --> 00:30:01,730 stars and the ones that never form stars 749 00:30:06,220 --> 00:30:04,790 at all and then here I'm highlighting 750 00:30:07,690 --> 00:30:06,230 both so in green now these are the 751 00:30:09,070 --> 00:30:07,700 galaxies that continue to form stars 752 00:30:10,660 --> 00:30:09,080 these are the classical satellites we've 753 00:30:12,970 --> 00:30:10,670 known about for decades in red and pink 754 00:30:14,800 --> 00:30:12,980 here these are the galaxies that got 755 00:30:16,810 --> 00:30:14,810 snuffed out right after the Big Bang and 756 00:30:18,790 --> 00:30:16,820 then most of these little clumps never 757 00:30:21,160 --> 00:30:18,800 form stars at all and that's the 758 00:30:22,450 --> 00:30:21,170 possible theoretical solution to the 759 00:30:23,680 --> 00:30:22,460 missing satellite problem is that these 760 00:30:24,850 --> 00:30:23,690 dark matter clumps are just sitting out 761 00:30:26,980 --> 00:30:24,860 there orbiting around they didn't form 762 00:30:30,640 --> 00:30:26,990 enough stars for us to see them so this 763 00:30:32,530 --> 00:30:30,650 is true if this is true we need to find 764 00:30:34,240 --> 00:30:32,540 these fossil galaxies these ones in red 765 00:30:35,920 --> 00:30:34,250 we've known about these ones in green 766 00:30:37,060 --> 00:30:35,930 for a long time and Frank showed some of 767 00:30:39,490 --> 00:30:37,070 those tonight I'll show you some 768 00:30:40,840 --> 00:30:39,500 pictures of other ones the key here 769 00:30:42,760 --> 00:30:40,850 since we can't see the dark matter 770 00:30:44,080 --> 00:30:42,770 clumps without stars to prove this 771 00:30:45,490 --> 00:30:44,090 theory you got to look at these pink 772 00:30:47,260 --> 00:30:45,500 ones and find evidence for fossil 773 00:30:48,750 --> 00:30:47,270 galaxies so that was the goal of a 774 00:30:53,170 --> 00:30:48,760 Hubble program we decided to undertake 775 00:30:54,790 --> 00:30:53,180 so if this theory is true we should have 776 00:30:55,840 --> 00:30:54,800 ancient dwarf galaxies besides the 777 00:30:57,490 --> 00:30:55,850 bright galaxies we've known about for 778 00:30:58,900 --> 00:30:57,500 decades this is Fornax one of the 779 00:31:01,930 --> 00:30:58,910 brightest satellite galaxies of the 780 00:31:04,840 --> 00:31:01,940 Milky Way it's a group of stars millions 781 00:31:07,630 --> 00:31:04,850 of stars with a very wide range of rage 782 00:31:09,310 --> 00:31:07,640 of ranges a range of Ages and a wide 783 00:31:10,570 --> 00:31:09,320 range of chemistry so I talk about 784 00:31:12,040 --> 00:31:10,580 chemistry I'm always talking irrelevant 785 00:31:14,200 --> 00:31:12,050 to the Sun so there's some stars that 786 00:31:16,780 --> 00:31:14,210 have just as many chemical but chemists 787 00:31:18,550 --> 00:31:16,790 chemical abundances as the Sun and we 788 00:31:19,990 --> 00:31:18,560 have some stars that are much much more 789 00:31:21,910 --> 00:31:20,000 metal-poor than the Sun there's like one 790 00:31:23,500 --> 00:31:21,920 percent of the metals the Sun has so 791 00:31:25,270 --> 00:31:23,510 wide range in chemistry wide range in 792 00:31:27,250 --> 00:31:25,280 ages from right after the Big Bang 13 793 00:31:28,810 --> 00:31:27,260 billion years old to up to just a few 794 00:31:33,400 --> 00:31:28,820 hundred million years old so this is 795 00:31:34,660 --> 00:31:33,410 Fornax has a wide range of Ages so a big 796 00:31:36,070 --> 00:31:34,670 step forward in the missing satellite 797 00:31:38,290 --> 00:31:36,080 problem is the Sloan Digital Sky Survey 798 00:31:39,970 --> 00:31:38,300 this was a survey of a wide range of the 799 00:31:42,010 --> 00:31:39,980 sky done with a small telescope on the 800 00:31:43,780 --> 00:31:42,020 ground New Mexico it's done from the 801 00:31:45,520 --> 00:31:43,790 ground this patch of sky is the 802 00:31:47,350 --> 00:31:45,530 summation of all the data from the 803 00:31:50,110 --> 00:31:47,360 Digital Sky Survey from a paper from 804 00:31:51,490 --> 00:31:50,120 Bella Cerf at all in 2007 this is tens 805 00:31:52,990 --> 00:31:51,500 of degrees across in the sky and they 806 00:31:55,210 --> 00:31:53,000 basically he basically summed up all the 807 00:31:57,280 --> 00:31:55,220 data from this scan of the sky and this 808 00:31:58,300 --> 00:31:57,290 scan revealed a lot of structure in the 809 00:31:59,380 --> 00:31:58,310 nearby universe we didn't know about 810 00:32:00,940 --> 00:31:59,390 before and you're Ike is already 811 00:32:03,310 --> 00:32:00,950 probably picking up on some of it but 812 00:32:05,170 --> 00:32:03,320 I'll highlight it here so in white I've 813 00:32:07,090 --> 00:32:05,180 highlighted three streams of tidal 814 00:32:09,490 --> 00:32:07,100 debris so this is the Sagittarii stream 815 00:32:10,750 --> 00:32:09,500 along here this is the orphan stream 816 00:32:13,570 --> 00:32:10,760 over here and this is the Montessori 817 00:32:15,280 --> 00:32:13,580 ring these are debris streams from 818 00:32:16,660 --> 00:32:15,290 satellite galaxies that fell into the 819 00:32:18,340 --> 00:32:16,670 gravitational well the Milky Way and 820 00:32:20,350 --> 00:32:18,350 then got disrupted by the tidal forces 821 00:32:22,480 --> 00:32:20,360 so the GAT the galaxies not really there 822 00:32:24,400 --> 00:32:22,490 anymore it's getting eaten alive by the 823 00:32:26,170 --> 00:32:24,410 Milky Way's gravitational well and it's 824 00:32:29,020 --> 00:32:26,180 just strewn across the sky this stream 825 00:32:30,580 --> 00:32:29,030 of stars here then they also found a lot 826 00:32:32,020 --> 00:32:30,590 of other little satellite galaxies which 827 00:32:33,550 --> 00:32:32,030 I've highlighted here in pink so these 828 00:32:34,660 --> 00:32:33,560 are new galaxies that were too faint to 829 00:32:36,880 --> 00:32:34,670 be noticed before but they're little 830 00:32:38,710 --> 00:32:36,890 over densities of stars so this went 831 00:32:40,210 --> 00:32:38,720 part of the way towards solving the 832 00:32:42,190 --> 00:32:40,220 missing satellite problems we had a few 833 00:32:43,690 --> 00:32:42,200 dozen galaxies and this found that well 834 00:32:44,980 --> 00:32:43,700 okay some of them are being disrupted 835 00:32:46,690 --> 00:32:44,990 which is making them hard to see these 836 00:32:48,640 --> 00:32:46,700 big streams and then other little ones 837 00:32:50,920 --> 00:32:48,650 were too faint to see these little faint 838 00:32:52,510 --> 00:32:50,930 ones are excellent candidates for these 839 00:32:53,830 --> 00:32:52,520 fossil galaxies that the theorists 840 00:32:55,570 --> 00:32:53,840 predicted they said okay well we didn't 841 00:32:57,580 --> 00:32:55,580 know about this ones before maybe these 842 00:32:59,830 --> 00:32:57,590 are these ancient fossil galaxies and 843 00:33:02,020 --> 00:32:59,840 there should be a big support for this 844 00:33:03,390 --> 00:33:02,030 theory so these ones we decided at 845 00:33:05,530 --> 00:33:03,400 Target with Hubble 846 00:33:07,420 --> 00:33:05,540 before I go on to that this is the dark 847 00:33:09,520 --> 00:33:07,430 energy survey this came out with results 848 00:33:11,620 --> 00:33:09,530 last year it found nine new satellite 849 00:33:12,970 --> 00:33:11,630 galaxies this is a projection on the sky 850 00:33:15,250 --> 00:33:12,980 of where they found them highlighted in 851 00:33:16,540 --> 00:33:15,260 blue here here's where they are in a 852 00:33:17,690 --> 00:33:16,550 different projection from two different 853 00:33:19,160 --> 00:33:17,700 papers that came out last year 854 00:33:20,780 --> 00:33:19,170 there are a lot of surveys right now 855 00:33:22,340 --> 00:33:20,790 from the ground this is a really active 856 00:33:23,660 --> 00:33:22,350 subfield of astronomer people are 857 00:33:25,250 --> 00:33:23,670 banging away it's mapping the whole sky 858 00:33:26,270 --> 00:33:25,260 trying to find the missing satellites 859 00:33:27,800 --> 00:33:26,280 but they're not coming up to the 860 00:33:29,150 --> 00:33:27,810 hundreds of satellites that theory 861 00:33:30,500 --> 00:33:29,160 predicts they're getting out there 862 00:33:32,540 --> 00:33:30,510 increasing the number from you know a 863 00:33:33,710 --> 00:33:32,550 few dozen to several more dozen but 864 00:33:35,300 --> 00:33:33,720 they're not coming up to the hundreds 865 00:33:37,100 --> 00:33:35,310 and that's because most of those 866 00:33:39,200 --> 00:33:37,110 galaxies are probably dark they have no 867 00:33:41,860 --> 00:33:39,210 stars that just comes to Dark Matter but 868 00:33:43,790 --> 00:33:41,870 we are finding more and more satellites 869 00:33:45,530 --> 00:33:43,800 so just to put things in perspective 870 00:33:47,480 --> 00:33:45,540 just to give you a sense of scale here 871 00:33:48,860 --> 00:33:47,490 here's a giant spiral galaxy of about a 872 00:33:50,990 --> 00:33:48,870 hundred billion stars in the upper left 873 00:33:53,720 --> 00:33:51,000 this is like the Milky Way or in 874 00:33:54,950 --> 00:33:53,730 Andromeda and down here is New York City 875 00:33:56,330 --> 00:33:54,960 I'm from New York's is the comparison 876 00:33:59,320 --> 00:33:56,340 going to use so this is 10 million 877 00:34:01,670 --> 00:33:59,330 people okay in the city of New York 878 00:34:03,380 --> 00:34:01,680 typical galaxies that orbit the Milky 879 00:34:05,090 --> 00:34:03,390 Way that we've known about for decades I 880 00:34:07,100 --> 00:34:05,100 like this here like for next 10 million 881 00:34:08,480 --> 00:34:07,110 stars scale down New York City you're 882 00:34:10,550 --> 00:34:08,490 talking about one theater showing The 883 00:34:11,600 --> 00:34:10,560 Lion King in New York City so this is 884 00:34:14,680 --> 00:34:11,610 the relative scale here we're talking 885 00:34:17,300 --> 00:34:14,690 about these ultra faint dwarf galaxies 886 00:34:18,980 --> 00:34:17,310 go down even further so they only have 887 00:34:20,600 --> 00:34:18,990 10,000 stars in them they're barely a 888 00:34:22,460 --> 00:34:20,610 galaxy at all and now you're talking 889 00:34:23,960 --> 00:34:22,470 about one guy in New York the host of 890 00:34:25,070 --> 00:34:23,970 the Jimmy Fallon show that sounds the 891 00:34:27,890 --> 00:34:25,080 relative scales here we're talking about 892 00:34:29,690 --> 00:34:27,900 so the Giants file like Andromeda or the 893 00:34:31,580 --> 00:34:29,700 Milky Way a classical dwarf like Fornax 894 00:34:35,419 --> 00:34:31,590 and these new ultra faint dwarf galaxies 895 00:34:37,190 --> 00:34:35,429 that were only recently discovered so 896 00:34:38,570 --> 00:34:37,200 when you show people the especially 897 00:34:39,830 --> 00:34:38,580 astronomers when I give this talk to 898 00:34:41,210 --> 00:34:39,840 professional astronomers in particular I 899 00:34:42,530 --> 00:34:41,220 sometimes get into arguments afterwards 900 00:34:44,270 --> 00:34:42,540 they say well why is that even a galaxy 901 00:34:45,440 --> 00:34:44,280 if it only has 10 mm stars in it because 902 00:34:47,990 --> 00:34:45,450 there are star clusters that have many 903 00:34:49,700 --> 00:34:48,000 more stars and that's true so this is a 904 00:34:51,050 --> 00:34:49,710 globular star cluster like the picture 905 00:34:53,150 --> 00:34:51,060 the Frank handed out tonight like a mega 906 00:34:54,710 --> 00:34:53,160 sin this one's actually a picture from 907 00:34:56,900 --> 00:34:54,720 that Andromeda image I took awhile ago 908 00:34:58,100 --> 00:34:56,910 that's a star cluster and Andromeda it's 909 00:34:59,780 --> 00:34:58,110 a cloud of the star cluster of a hundred 910 00:35:01,610 --> 00:34:59,790 thousand stars and this is an ultra 911 00:35:03,500 --> 00:35:01,620 faint dwarf galaxy of 10,000 stars so 912 00:35:04,880 --> 00:35:03,510 why is this a galaxy and that's a star 913 00:35:06,860 --> 00:35:04,890 cluster and the reason is because it's 914 00:35:08,990 --> 00:35:06,870 dark matter as well as talked about 915 00:35:10,700 --> 00:35:09,000 earlier globular clusters as far as we 916 00:35:12,440 --> 00:35:10,710 can tell have little to no dark matter 917 00:35:13,730 --> 00:35:12,450 so if you measure the mass to light 918 00:35:16,070 --> 00:35:13,740 ratio which is something astronomers 919 00:35:18,710 --> 00:35:16,080 doing these objects in units of the Sun 920 00:35:20,390 --> 00:35:18,720 you can amass the light ratio of about 921 00:35:21,740 --> 00:35:20,400 two which is consistent with an old 922 00:35:23,330 --> 00:35:21,750 population of stars that means there's 923 00:35:25,040 --> 00:35:23,340 compared to the Sun there's a you know 924 00:35:27,320 --> 00:35:25,050 the ratio of mass to light in the Sun 925 00:35:28,250 --> 00:35:27,330 these globular clusters have about twice 926 00:35:29,720 --> 00:35:28,260 as much mass to 927 00:35:31,310 --> 00:35:29,730 ratio and that's because most of the 928 00:35:33,230 --> 00:35:31,320 stars are really faint and dim compared 929 00:35:34,580 --> 00:35:33,240 to the Sun most stars and universe are 930 00:35:37,340 --> 00:35:34,590 really faint endemic compared to the Sun 931 00:35:40,010 --> 00:35:37,350 in contrast these ultra faint Dorf 932 00:35:41,360 --> 00:35:40,020 galaxies have a lot of dark matter again 933 00:35:43,250 --> 00:35:41,370 because dark matter is the scaffolding 934 00:35:44,570 --> 00:35:43,260 upon which galaxies are built so 935 00:35:46,370 --> 00:35:44,580 galaxies have significant dark matter 936 00:35:47,630 --> 00:35:46,380 the classical dwarf galaxies we've known 937 00:35:50,300 --> 00:35:47,640 about for decades have mass-to-light 938 00:35:51,980 --> 00:35:50,310 ratios exceeding 10 and the ultra faint 939 00:35:54,320 --> 00:35:51,990 dwarf galaxies have master light ratios 940 00:35:56,030 --> 00:35:54,330 exceeding 100 so these new galaxies are 941 00:35:57,320 --> 00:35:56,040 almost entirely dark matter this is the 942 00:35:59,030 --> 00:35:57,330 big clump of dark matter there with a 943 00:36:00,410 --> 00:35:59,040 few stars sprinkled on top which is 944 00:36:02,090 --> 00:36:00,420 consistent with this theory that the 945 00:36:03,380 --> 00:36:02,100 theorists used to predict you know the 946 00:36:04,910 --> 00:36:03,390 solutions the missing satellite problem 947 00:36:06,590 --> 00:36:04,920 is that they had the Dark Matter they're 948 00:36:07,760 --> 00:36:06,600 a few stars formed and then things were 949 00:36:09,380 --> 00:36:07,770 turned off the lights were turned off 950 00:36:12,260 --> 00:36:09,390 when when the most of the universe came 951 00:36:13,790 --> 00:36:12,270 out in the star formation another big 952 00:36:15,020 --> 00:36:13,800 difference is that globular clusters are 953 00:36:17,330 --> 00:36:15,030 usually what we call simple stellar 954 00:36:18,620 --> 00:36:17,340 populations all the stars to first order 955 00:36:20,540 --> 00:36:18,630 are just one age and one chemical 956 00:36:24,140 --> 00:36:20,550 composition you have a cloud out there 957 00:36:25,760 --> 00:36:24,150 in space it collapses you form a bunch 958 00:36:27,770 --> 00:36:25,770 of stars they all have one age one 959 00:36:29,660 --> 00:36:27,780 chemical composition galaxies have a 960 00:36:31,070 --> 00:36:29,670 wide range in ages and a wide range of 961 00:36:32,630 --> 00:36:31,080 chemical composition that's true of 962 00:36:35,420 --> 00:36:32,640 every galaxy that we've known about 963 00:36:37,040 --> 00:36:35,430 until the ones I'll show you tonight so 964 00:36:38,030 --> 00:36:37,050 this is a plot now of just put these 965 00:36:40,040 --> 00:36:38,040 things into perspective this is 966 00:36:42,080 --> 00:36:40,050 luminosity relative to the Sun so 10 to 967 00:36:43,820 --> 00:36:42,090 the 6 is a million times luminosity of 968 00:36:46,550 --> 00:36:43,830 the Sun this is diameter in lightyears 969 00:36:47,840 --> 00:36:46,560 from one to a thousand so star clusters 970 00:36:49,520 --> 00:36:47,850 fall over here these are globular 971 00:36:51,020 --> 00:36:49,530 clusters they have up to a million times 972 00:36:52,340 --> 00:36:51,030 the luminosity the Sun or maybe even a 973 00:36:53,720 --> 00:36:52,350 thousand times the luminosity of the Sun 974 00:36:55,730 --> 00:36:53,730 but they're pretty compact than the 975 00:36:57,380 --> 00:36:55,740 left-hand side of this diagram the 976 00:36:58,910 --> 00:36:57,390 classical dwarf galaxies are shown here 977 00:37:00,470 --> 00:36:58,920 in blue so they're much more extended 978 00:37:01,880 --> 00:37:00,480 and they're generally brighter than star 979 00:37:03,980 --> 00:37:01,890 clusters they're up and to the right 980 00:37:05,750 --> 00:37:03,990 these ultra faint dork galaxies are down 981 00:37:07,610 --> 00:37:05,760 here they're an extension of these dwarf 982 00:37:09,620 --> 00:37:07,620 galaxies to faint your luminosities and 983 00:37:11,810 --> 00:37:09,630 smaller sizes but they're not as compact 984 00:37:13,610 --> 00:37:11,820 as globular clusters so they're mostly 985 00:37:15,730 --> 00:37:13,620 dark matter and they're these wispy 986 00:37:18,200 --> 00:37:15,740 things with just a few stars on them and 987 00:37:19,610 --> 00:37:18,210 so we decide to look at these six very 988 00:37:21,230 --> 00:37:19,620 closely with Hubble because Hubble is 989 00:37:25,760 --> 00:37:21,240 excellent in measuring the ages of stars 990 00:37:27,200 --> 00:37:25,770 to test these theories so how do we know 991 00:37:28,610 --> 00:37:27,210 of a group of stars is old well there's 992 00:37:29,900 --> 00:37:28,620 two ways you can go about it one is to 993 00:37:31,190 --> 00:37:29,910 get spectra these stars you take the 994 00:37:33,080 --> 00:37:31,200 light from the stars you've spread it 995 00:37:35,090 --> 00:37:33,090 out into its rainbow and then you look 996 00:37:36,560 --> 00:37:35,100 for features in that spectrum to see 997 00:37:38,510 --> 00:37:36,570 what kind of metal abundances there are 998 00:37:39,890 --> 00:37:38,520 and so if we want to see if it's old it 999 00:37:41,560 --> 00:37:39,900 should have a low abundance of metals if 1000 00:37:42,940 --> 00:37:41,570 it was born in the early universe before 1001 00:37:44,650 --> 00:37:42,950 there are many generations of stars the 1002 00:37:45,790 --> 00:37:44,660 gas should be pretty pristine and so 1003 00:37:48,040 --> 00:37:45,800 there shouldn't be a very high chemical 1004 00:37:49,150 --> 00:37:48,050 composition in these stars we also do 1005 00:37:51,070 --> 00:37:49,160 photometry we measure the brightness 1006 00:37:52,750 --> 00:37:51,080 --is and colors of the stars and when we 1007 00:37:55,750 --> 00:37:52,760 do that we can see what masses are left 1008 00:37:57,250 --> 00:37:55,760 only low mass stars less massive than 1009 00:37:59,500 --> 00:37:57,260 the Sun should be present if it's old 1010 00:38:01,870 --> 00:37:59,510 because massive stars more massive than 1011 00:38:03,250 --> 00:38:01,880 the Sun die very quickly so these are 1012 00:38:07,150 --> 00:38:03,260 the two tests we do to see if these 1013 00:38:09,220 --> 00:38:07,160 things are actually old galaxies so 1014 00:38:11,110 --> 00:38:09,230 here's a spectrum from ultra main Dorf 1015 00:38:12,220 --> 00:38:11,120 galaxies and it tells us a couple 1016 00:38:13,690 --> 00:38:12,230 different things so well you know it 1017 00:38:15,880 --> 00:38:13,700 gets broken into its constituent light 1018 00:38:17,200 --> 00:38:15,890 from blue green to red and these little 1019 00:38:19,060 --> 00:38:17,210 dark patches and their absorption 1020 00:38:21,340 --> 00:38:19,070 features from metals in the atmosphere 1021 00:38:23,830 --> 00:38:21,350 of the star so by usually measuring the 1022 00:38:25,240 --> 00:38:23,840 velocities we from the Doppler effect of 1023 00:38:26,950 --> 00:38:25,250 these absorption features we can measure 1024 00:38:28,450 --> 00:38:26,960 the motions of these stars and the 1025 00:38:30,280 --> 00:38:28,460 motions of the stars and the old faint 1026 00:38:32,950 --> 00:38:30,290 Dorf galaxies imply there's a lot of 1027 00:38:35,230 --> 00:38:32,960 dark matter there so the matter in these 1028 00:38:36,700 --> 00:38:35,240 galaxies the luminous matter is feeling 1029 00:38:39,190 --> 00:38:36,710 the presence of the gravity gravity from 1030 00:38:40,660 --> 00:38:39,200 the dark matter the absorption features 1031 00:38:42,340 --> 00:38:40,670 these little patches here are also very 1032 00:38:44,440 --> 00:38:42,350 weak so it means these stars have a 1033 00:38:46,570 --> 00:38:44,450 hundred to ten thousand times fewer 1034 00:38:48,070 --> 00:38:46,580 metals than the Sun so these stars were 1035 00:38:49,630 --> 00:38:48,080 really born in the early universe when 1036 00:38:51,730 --> 00:38:49,640 the gas was still pretty pristine and 1037 00:38:53,440 --> 00:38:51,740 many this is also a little cottage 1038 00:38:54,790 --> 00:38:53,450 industry in astronomy a lot of people 1039 00:38:56,380 --> 00:38:54,800 are looking for the first stars and the 1040 00:38:57,790 --> 00:38:56,390 earliest stars and oldest stars and 1041 00:38:59,110 --> 00:38:57,800 folks who are looking for the most 1042 00:39:00,640 --> 00:38:59,120 metal-poor stars have found a lot of 1043 00:39:01,870 --> 00:39:00,650 them in these ultra faint dwarf galaxies 1044 00:39:05,560 --> 00:39:01,880 so this is fertile ground for these 1045 00:39:06,910 --> 00:39:05,570 searches so this is the same handout you 1046 00:39:08,590 --> 00:39:06,920 have tonight this Omega sign so it's 1047 00:39:10,480 --> 00:39:08,600 fortunate that Frank came to that hands 1048 00:39:11,710 --> 00:39:10,490 out I'm going to sort this is an image 1049 00:39:13,780 --> 00:39:11,720 from Hubble with the Wide Field Camera 3 1050 00:39:15,250 --> 00:39:13,790 is a camera I worked on before I 1051 00:39:17,080 --> 00:39:15,260 switched over to James Webb for a while 1052 00:39:20,140 --> 00:39:17,090 I'm going to sort this this is from my 1053 00:39:21,820 --> 00:39:20,150 collaborator colleague J Anderson we 1054 00:39:23,890 --> 00:39:21,830 sort this in color first from left to 1055 00:39:25,840 --> 00:39:23,900 right so hotter stars that are blue will 1056 00:39:28,930 --> 00:39:25,850 be on the Left cooler stars that are red 1057 00:39:30,220 --> 00:39:28,940 will be on the right then we're going to 1058 00:39:31,900 --> 00:39:30,230 sort it in luminosity with brighter 1059 00:39:35,380 --> 00:39:31,910 stars at the top fainter stars at the 1060 00:39:37,450 --> 00:39:35,390 bottom when you do that you see that 1061 00:39:39,370 --> 00:39:37,460 stars don't just have random colors and 1062 00:39:40,930 --> 00:39:39,380 random brightnesses it actually traced 1063 00:39:42,490 --> 00:39:40,940 out a very specific pattern my wife 1064 00:39:44,590 --> 00:39:42,500 calls this the duct diagram because our 1065 00:39:46,090 --> 00:39:44,600 minds are of a duct but anyway here's 1066 00:39:48,010 --> 00:39:46,100 the body here's the neck who's the beak 1067 00:39:50,110 --> 00:39:48,020 but main sequence stars like the Sun 1068 00:39:53,260 --> 00:39:50,120 that are burning hydrogen fall down here 1069 00:39:54,460 --> 00:39:53,270 and then have to exhaust their hydrogen 1070 00:39:55,330 --> 00:39:54,470 they go up here and become red giant 1071 00:39:57,370 --> 00:39:55,340 stars 1072 00:39:58,570 --> 00:39:57,380 and then they finally burn helium they 1073 00:40:00,070 --> 00:39:58,580 become this thing called horizontal 1074 00:40:02,260 --> 00:40:00,080 branch stars because this distributions 1075 00:40:04,450 --> 00:40:02,270 horizontal say burn helium then they die 1076 00:40:06,280 --> 00:40:04,460 as white dwarfs so when you sort a 1077 00:40:08,050 --> 00:40:06,290 population of stars by brightness and 1078 00:40:09,490 --> 00:40:08,060 color they're not random they trace had 1079 00:40:11,800 --> 00:40:09,500 a very specific pattern that's the life 1080 00:40:13,330 --> 00:40:11,810 cycle of the star and that's how we can 1081 00:40:15,790 --> 00:40:13,340 use that information to tell how old a 1082 00:40:17,260 --> 00:40:15,800 group of stars of this so that's where 1083 00:40:18,700 --> 00:40:17,270 those stars now fall in that image of a 1084 00:40:24,220 --> 00:40:18,710 magazine which is on the handout over 1085 00:40:25,990 --> 00:40:24,230 here so here's measurements of a galaxy 1086 00:40:27,550 --> 00:40:26,000 this is brightness again on the y axis 1087 00:40:29,650 --> 00:40:27,560 here in these funny hoots astronomers 1088 00:40:32,770 --> 00:40:29,660 use so this is in a filter 8:14 so 800 1089 00:40:35,080 --> 00:40:32,780 nanometer filter 606 minus 814 600 1090 00:40:36,490 --> 00:40:35,090 nanometer minus 800 nanometer filter so 1091 00:40:38,530 --> 00:40:36,500 this is a color with redder stars on the 1092 00:40:40,120 --> 00:40:38,540 right bluer stars on the left brighter 1093 00:40:42,580 --> 00:40:40,130 stars at the top fainter stars at the 1094 00:40:45,520 --> 00:40:42,590 bottom hydrogen burning stars fall along 1095 00:40:47,440 --> 00:40:45,530 here here's this kink and then they 1096 00:40:49,000 --> 00:40:47,450 exhaust hydrogen the core and then you 1097 00:40:51,070 --> 00:40:49,010 become a red giant star and that's how 1098 00:40:54,070 --> 00:40:51,080 you measure the age of a population so 1099 00:40:55,840 --> 00:40:54,080 these are low mass hydrogen burning 1100 00:40:57,520 --> 00:40:55,850 stars more massive hydrogen burning 1101 00:41:00,130 --> 00:40:57,530 stars and then they peel off and become 1102 00:41:02,080 --> 00:41:00,140 red giants so these are stars that are 1103 00:41:03,520 --> 00:41:02,090 still burning hydrogen in the core these 1104 00:41:06,400 --> 00:41:03,530 are stars that exhausted hydrogen the 1105 00:41:08,380 --> 00:41:06,410 quorum become Giants so that's the clock 1106 00:41:09,940 --> 00:41:08,390 that little kink right there tells you 1107 00:41:10,900 --> 00:41:09,950 that's the best clock in astronomy right 1108 00:41:12,250 --> 00:41:10,910 now there's a lot of different ways to 1109 00:41:13,780 --> 00:41:12,260 measure the ages of stars but that's the 1110 00:41:17,410 --> 00:41:13,790 gold standard since Allan Sandage 1111 00:41:19,150 --> 00:41:17,420 started doing this in the 50s so this is 1112 00:41:20,920 --> 00:41:19,160 for you get for a population that's 13 1113 00:41:22,120 --> 00:41:20,930 billion years old an ancient population 1114 00:41:23,550 --> 00:41:22,130 and that's what it would look like for a 1115 00:41:25,600 --> 00:41:23,560 population that's 6 billion years old 1116 00:41:26,470 --> 00:41:25,610 and that's what it is for 13 billion 1117 00:41:28,030 --> 00:41:26,480 years old it's a very dramatic 1118 00:41:29,590 --> 00:41:28,040 difference and the reason why is because 1119 00:41:31,780 --> 00:41:29,600 the massive stars die more quickly than 1120 00:41:32,980 --> 00:41:31,790 the less massive stars ironically if 1121 00:41:34,360 --> 00:41:32,990 you're a massive star you have a lot of 1122 00:41:35,590 --> 00:41:34,370 fuel but you're very bright you burn it 1123 00:41:37,630 --> 00:41:35,600 very quickly so you'll leave the main 1124 00:41:41,560 --> 00:41:37,640 sequence to become a giant more rapidly 1125 00:41:44,020 --> 00:41:41,570 than these stars down here so here's the 1126 00:41:46,780 --> 00:41:44,030 Carina two classical dwarf galaxies is 1127 00:41:48,670 --> 00:41:46,790 out in the local group again a pretty 1128 00:41:51,160 --> 00:41:48,680 massive dwarf galaxy we've known about 1129 00:41:52,750 --> 00:41:51,170 for decades and here's its color 1130 00:41:54,460 --> 00:41:52,760 magnitude diagram so this is brightness 1131 00:41:56,940 --> 00:41:54,470 on the y axis color on the x axis and 1132 00:41:59,350 --> 00:41:56,950 you get these three distinct little 1133 00:42:01,210 --> 00:41:59,360 shapes here each of those is from a 1134 00:42:04,000 --> 00:42:01,220 burst of star formation if I put models 1135 00:42:05,410 --> 00:42:04,010 on top of that this is where stars about 1136 00:42:07,540 --> 00:42:05,420 half a billion years old would lie and 1137 00:42:08,890 --> 00:42:07,550 this brighter curve here stars five 1138 00:42:10,390 --> 00:42:08,900 billion years old with 1139 00:42:12,220 --> 00:42:10,400 along this intermediate curve here and 1140 00:42:14,020 --> 00:42:12,230 really old stars 11 billion years old 1141 00:42:15,550 --> 00:42:14,030 would lie here so this is a kind of 1142 00:42:17,590 --> 00:42:15,560 curious galaxy you don't usually see 1143 00:42:18,910 --> 00:42:17,600 these episodes of star formation but in 1144 00:42:20,140 --> 00:42:18,920 this one you did and it makes it kind of 1145 00:42:22,360 --> 00:42:20,150 interesting to show the clock in three 1146 00:42:24,280 --> 00:42:22,370 different paces one two three and this 1147 00:42:25,600 --> 00:42:24,290 is similar to the stories we've seen for 1148 00:42:27,070 --> 00:42:25,610 a lot of dwarf galaxies there's a wide 1149 00:42:28,120 --> 00:42:27,080 range of Ages you know you don't see 1150 00:42:29,560 --> 00:42:28,130 just old stars you know interesting 1151 00:42:32,980 --> 00:42:29,570 young stars usually see a wide range of 1152 00:42:34,270 --> 00:42:32,990 Ages so here's the ones we decided to 1153 00:42:36,490 --> 00:42:34,280 look at again tonight the ultra main 1154 00:42:39,640 --> 00:42:36,500 doors and again I looked at these with 1155 00:42:41,080 --> 00:42:39,650 Hubble they're kind of a sample of that 1156 00:42:43,390 --> 00:42:41,090 six galaxies out of the recently 1157 00:42:44,650 --> 00:42:43,400 discovered ones from Sloan and this is 1158 00:42:46,120 --> 00:42:44,660 what it looks like when Hubble looks at 1159 00:42:47,920 --> 00:42:46,130 one of these so in the background here 1160 00:42:49,780 --> 00:42:47,930 I'm showing a Digital Sky Survey image 1161 00:42:51,040 --> 00:42:49,790 and then Hubble has a pretty small field 1162 00:42:53,140 --> 00:42:51,050 of view compared to some of these ground 1163 00:42:54,730 --> 00:42:53,150 telescopes so the footprint from Hubble 1164 00:42:56,920 --> 00:42:54,740 from its advanced camera for surveys is 1165 00:42:59,650 --> 00:42:56,930 one of these blue tiles here we kind of 1166 00:43:01,840 --> 00:42:59,660 went and tile that part of the galaxy we 1167 00:43:03,850 --> 00:43:01,850 turned on Wide Field Camera 3 in pink 1168 00:43:05,050 --> 00:43:03,860 here in parallel it kind of missed the 1169 00:43:06,160 --> 00:43:05,060 galaxies here so it was just getting a 1170 00:43:08,950 --> 00:43:06,170 sample of some of the stars in the 1171 00:43:12,400 --> 00:43:08,960 background this is about 200 arc seconds 1172 00:43:14,560 --> 00:43:12,410 on the side this is Leo 4 so this 1173 00:43:15,970 --> 00:43:14,570 galaxies further out from the Milky Way 1174 00:43:17,380 --> 00:43:15,980 so it's a little more compact on the sky 1175 00:43:18,790 --> 00:43:17,390 so if you look carefully you can see 1176 00:43:20,620 --> 00:43:18,800 there's an over density of stars right 1177 00:43:22,480 --> 00:43:20,630 here compared to the background and so 1178 00:43:24,280 --> 00:43:22,490 we stuck a CS the advanced camera for 1179 00:43:25,540 --> 00:43:24,290 surveys right here we stuck will feel 1180 00:43:27,730 --> 00:43:25,550 camera 3 out here it got pretty much 1181 00:43:31,000 --> 00:43:27,740 nothing but this one measured the 1182 00:43:34,450 --> 00:43:31,010 galaxies and so that's the image we got 1183 00:43:37,870 --> 00:43:34,460 of Leo 4 in that patch that's this patch 1184 00:43:39,730 --> 00:43:37,880 of sky right here this is the Hubble 1185 00:43:41,080 --> 00:43:39,740 image it's about 16 orbits we hand out 1186 00:43:42,310 --> 00:43:41,090 time on Hubble and units of orbits 1187 00:43:43,870 --> 00:43:42,320 Hubble goes around the earth every 96 1188 00:43:45,940 --> 00:43:43,880 minutes that's the currency and Hubble 1189 00:43:48,460 --> 00:43:45,950 so you know people asked for 5 orbits 10 1190 00:43:50,140 --> 00:43:48,470 orbits 100 orbits this was 16 orbits on 1191 00:43:52,270 --> 00:43:50,150 this one galaxy we looked at six 1192 00:43:53,860 --> 00:43:52,280 galaxies in total it's a fairly deep 1193 00:43:55,210 --> 00:43:53,870 image like a lot of images with Hubble 1194 00:43:56,020 --> 00:43:55,220 when you're trying to go deep you get 1195 00:43:57,070 --> 00:43:56,030 the rest of the universe in the 1196 00:43:58,990 --> 00:43:57,080 background so there's all these really 1197 00:44:00,190 --> 00:43:59,000 pretty galaxies in the background and a 1198 00:44:01,420 --> 00:44:00,200 lot of people like those because the 1199 00:44:03,070 --> 00:44:01,430 stars are just points that are kind of 1200 00:44:04,000 --> 00:44:03,080 boring but for me it's wasted real 1201 00:44:04,990 --> 00:44:04,010 estate because every one of these 1202 00:44:06,400 --> 00:44:05,000 patches is where I can't make 1203 00:44:07,780 --> 00:44:06,410 measurements of the star so people like 1204 00:44:10,450 --> 00:44:07,790 these galaxies they're just kind of 1205 00:44:12,190 --> 00:44:10,460 irritating to me but I'll zoom in on a 1206 00:44:14,470 --> 00:44:12,200 patch here so here's this yellow box 1207 00:44:15,850 --> 00:44:14,480 that I'm going to zoom in so again you 1208 00:44:17,590 --> 00:44:15,860 have these nice beautiful galaxies in 1209 00:44:19,660 --> 00:44:17,600 the background which I just mask out and 1210 00:44:22,270 --> 00:44:19,670 far away and then you have these points 1211 00:44:24,280 --> 00:44:22,280 which are stars in Leo for 1212 00:44:26,050 --> 00:44:24,290 I like two of them these are the most 1213 00:44:28,570 --> 00:44:26,060 massive hydrogen burning stars in Leo 1214 00:44:29,980 --> 00:44:28,580 four so these tell you the clock so when 1215 00:44:31,780 --> 00:44:29,990 you get measurements of the brightness 1216 00:44:33,520 --> 00:44:31,790 and colors of these stars that tells you 1217 00:44:35,320 --> 00:44:33,530 how well the galaxy is so these are the 1218 00:44:39,310 --> 00:44:35,330 brightest hydrogen burning stars in Leo 1219 00:44:40,900 --> 00:44:39,320 four so here's the image again and what 1220 00:44:43,300 --> 00:44:40,910 I'm going to do now is highlight the 1221 00:44:45,310 --> 00:44:43,310 stars in this image and show you how 1222 00:44:46,660 --> 00:44:45,320 they tell us the clock for the galaxies 1223 00:44:48,580 --> 00:44:46,670 so this is the these are the stars in 1224 00:44:50,740 --> 00:44:48,590 Leo 4 if I sort them in color and 1225 00:44:52,480 --> 00:44:50,750 luminosity that's where they fall at an 1226 00:44:54,880 --> 00:44:52,490 age of around 13 billion years and now I 1227 00:44:56,770 --> 00:44:54,890 can use theory of stellar evolution to 1228 00:44:58,210 --> 00:44:56,780 roll back the clock here so now I'm 1229 00:44:59,710 --> 00:44:58,220 taking the data and just morphing it 1230 00:45:01,390 --> 00:44:59,720 backwards in time towards the Big Bang 1231 00:45:03,040 --> 00:45:01,400 so now this is what the data would look 1232 00:45:05,190 --> 00:45:03,050 like if we made that measurement a 1233 00:45:07,570 --> 00:45:05,200 billion years after the galaxy was born 1234 00:45:09,490 --> 00:45:07,580 so this brightness over here color over 1235 00:45:11,770 --> 00:45:09,500 here and now the clocks rolling forwards 1236 00:45:13,120 --> 00:45:11,780 to the present era so five billion years 1237 00:45:14,710 --> 00:45:13,130 six million years and here's the clock 1238 00:45:17,560 --> 00:45:14,720 is right here this kink this tells you 1239 00:45:18,910 --> 00:45:17,570 how old the population of stars is until 1240 00:45:21,310 --> 00:45:18,920 you get to the galaxy being about 13 1241 00:45:22,690 --> 00:45:21,320 billion years old today and those are 1242 00:45:28,630 --> 00:45:22,700 the points and this is where they fall 1243 00:45:30,550 --> 00:45:28,640 in that image so these the data we got 1244 00:45:31,780 --> 00:45:30,560 so we got six of these duck diagrams 1245 00:45:33,280 --> 00:45:31,790 like I said these contracted diaries 1246 00:45:35,140 --> 00:45:33,290 with my wife calls on duck diagrams and 1247 00:45:36,910 --> 00:45:35,150 the first one we got was here and now 1248 00:45:38,410 --> 00:45:36,920 here's full disclosure I'm an observer I 1249 00:45:40,330 --> 00:45:38,420 have a team of folks on here some work 1250 00:45:42,160 --> 00:45:40,340 on Hubble like me some work on Keck I 1251 00:45:44,020 --> 00:45:42,170 have some theorists on the team and I'm 1252 00:45:45,850 --> 00:45:44,030 used to theorist not to be disparaging a 1253 00:45:47,410 --> 00:45:45,860 theorist coming up with a theory and 1254 00:45:49,900 --> 00:45:47,420 then you go test and you go well let me 1255 00:45:51,850 --> 00:45:49,910 revise that theory so we got these data 1256 00:45:53,590 --> 00:45:51,860 right here and because I work on these 1257 00:45:54,970 --> 00:45:53,600 kind of diagrams a lot I immediately saw 1258 00:45:57,010 --> 00:45:54,980 in my office that this was a very 1259 00:45:57,850 --> 00:45:57,020 ancient population which is not what I 1260 00:45:59,950 --> 00:45:57,860 was expecting 1261 00:46:01,660 --> 00:45:59,960 I wrote this proposal to measure how all 1262 00:46:03,130 --> 00:46:01,670 these stars were and I was sure just 1263 00:46:04,570 --> 00:46:03,140 like every galaxy we've ever measured 1264 00:46:06,820 --> 00:46:04,580 before there would be young stars and 1265 00:46:09,100 --> 00:46:06,830 old stars but instead the stars were all 1266 00:46:10,150 --> 00:46:09,110 just old and I almost fell out of my 1267 00:46:11,290 --> 00:46:10,160 chair and you're looking at these and 1268 00:46:13,240 --> 00:46:11,300 going okay it's a bunch of yellow dots 1269 00:46:14,860 --> 00:46:13,250 but for me it was really surprising 1270 00:46:16,570 --> 00:46:14,870 because I did not expect the theory to 1271 00:46:18,100 --> 00:46:16,580 be true and so I called up Jason 1272 00:46:19,930 --> 00:46:18,110 Tomlinson who made that simulation in 1273 00:46:21,220 --> 00:46:19,940 the beginning of my talk tried him down 1274 00:46:22,630 --> 00:46:21,230 to my office he works one floor up for 1275 00:46:23,650 --> 00:46:22,640 me here in this building and he said 1276 00:46:24,880 --> 00:46:23,660 well yeah that's what's supposed to do 1277 00:46:26,170 --> 00:46:24,890 they're supposed to be old and I said 1278 00:46:27,640 --> 00:46:26,180 yeah but I didn't think that was really 1279 00:46:28,630 --> 00:46:27,650 going to happen I thought there was 1280 00:46:30,160 --> 00:46:28,640 going to be young stars and old stars 1281 00:46:32,230 --> 00:46:30,170 just like every galaxy we've ever looked 1282 00:46:33,930 --> 00:46:32,240 at before so those were the first data 1283 00:46:35,960 --> 00:46:33,940 that executed the program Hercules 1284 00:46:37,880 --> 00:46:35,970 satellite the Milky Way and then 1285 00:46:39,470 --> 00:46:37,890 got the other five galaxies and they're 1286 00:46:40,520 --> 00:46:39,480 all in different positions in each of 1287 00:46:41,599 --> 00:46:40,530 these diagrams here cuz some are closed 1288 00:46:44,150 --> 00:46:41,609 or some are furthest that makes the 1289 00:46:45,230 --> 00:46:44,160 stars brighter and fainter but if you do 1290 00:46:46,880 --> 00:46:45,240 this kind of work you look at each of 1291 00:46:48,140 --> 00:46:46,890 these you say oh my god the stars are 1292 00:46:49,609 --> 00:46:48,150 really ancient every one of these 1293 00:46:50,990 --> 00:46:49,619 galaxies they also look very similar 1294 00:46:53,109 --> 00:46:51,000 these diagrams all look very similar to 1295 00:46:56,000 --> 00:46:53,119 each other so just for a comparison 1296 00:46:57,740 --> 00:46:56,010 without using any theory I'm going to 1297 00:46:59,540 --> 00:46:57,750 take data from another well studied 1298 00:47:00,710 --> 00:46:59,550 object that we use to make comparisons 1299 00:47:03,620 --> 00:47:00,720 the data like I just showed you this is 1300 00:47:05,480 --> 00:47:03,630 m92 NGC 634 one it's one of the most 1301 00:47:06,080 --> 00:47:05,490 well studied ancient objects in the 1302 00:47:08,030 --> 00:47:06,090 universe 1303 00:47:10,339 --> 00:47:08,040 it's a metal-poor star cluster Allan 1304 00:47:12,410 --> 00:47:10,349 Sandage looked at this in the 1950s to 1305 00:47:13,640 --> 00:47:12,420 figure out how stars evolve it's an 1306 00:47:15,589 --> 00:47:13,650 ancient star cluster 1307 00:47:17,089 --> 00:47:15,599 its chemical abundances are such that 1308 00:47:19,370 --> 00:47:17,099 the metals in the atmosphere are less 1309 00:47:21,620 --> 00:47:19,380 than 1% of the abundance in the Sun it's 1310 00:47:24,230 --> 00:47:21,630 a globular cluster this is a half second 1311 00:47:25,460 --> 00:47:24,240 exposure on Hubble Allan Sandage would 1312 00:47:26,720 --> 00:47:25,470 spend nights of the telescope in the 1313 00:47:27,440 --> 00:47:26,730 ground looking at this with Hubble's so 1314 00:47:28,970 --> 00:47:27,450 powerful this is 1315 00:47:30,710 --> 00:47:28,980 oops this is just a half second exposure 1316 00:47:33,440 --> 00:47:30,720 this is the advanced camera for surveys 1317 00:47:35,450 --> 00:47:33,450 it's kind of like your CC the CCD chip 1318 00:47:37,640 --> 00:47:35,460 on here is kind of like your chip on 1319 00:47:39,290 --> 00:47:37,650 your digital camera now there's a crack 1320 00:47:41,329 --> 00:47:39,300 down the middle here splits the chip 1321 00:47:42,950 --> 00:47:41,339 into two halves so that's why you see 1322 00:47:44,900 --> 00:47:42,960 this two sections here but it's a 4k by 1323 00:47:46,940 --> 00:47:44,910 4k image the 16 megapixel camera 1324 00:47:49,810 --> 00:47:46,950 basically on Hubble and all these are 1325 00:47:52,910 --> 00:47:49,820 stars in this globular cluster m92 1326 00:47:55,430 --> 00:47:52,920 this is the climactic diagram from those 1327 00:47:56,960 --> 00:47:55,440 data so this is the luminosity here 1328 00:47:59,390 --> 00:47:56,970 bright stars at the top here's the color 1329 00:48:00,650 --> 00:47:59,400 red stars on the right and again stars 1330 00:48:02,150 --> 00:48:00,660 don't just have random colors and 1331 00:48:04,430 --> 00:48:02,160 brightnesses they trace out this very 1332 00:48:05,960 --> 00:48:04,440 specific pattern that's the lifecycle of 1333 00:48:07,310 --> 00:48:05,970 the star hydrogen burning stars the 1334 00:48:08,390 --> 00:48:07,320 exhaust hydrogen go up here become red 1335 00:48:11,060 --> 00:48:08,400 giants that come over here and burn 1336 00:48:13,130 --> 00:48:11,070 helium and this is the kink right here 1337 00:48:15,500 --> 00:48:13,140 it tells you the age so what I can do is 1338 00:48:17,329 --> 00:48:15,510 I can say all right I'll highlight the 1339 00:48:19,339 --> 00:48:17,339 helium burning stars over here and then 1340 00:48:21,290 --> 00:48:19,349 I'll draw a curve through this and I'll 1341 00:48:22,970 --> 00:48:21,300 just compare that to the data I got on 1342 00:48:24,530 --> 00:48:22,980 those galaxies this is an ancient star 1343 00:48:27,859 --> 00:48:24,540 cluster 13 billion years old that's been 1344 00:48:29,690 --> 00:48:27,869 studied for 60 years so here are the 1345 00:48:32,900 --> 00:48:29,700 data on the new galaxies that we found 1346 00:48:33,980 --> 00:48:32,910 and here's where the m92 data fall when 1347 00:48:35,960 --> 00:48:33,990 you superimpose them at the same 1348 00:48:38,359 --> 00:48:35,970 distance and goes right through the data 1349 00:48:39,500 --> 00:48:38,369 in every case and really this was I know 1350 00:48:41,089 --> 00:48:39,510 how shocking is to you but I was 1351 00:48:42,470 --> 00:48:41,099 flabbergasted when we did this that all 1352 00:48:44,030 --> 00:48:42,480 these galaxies which like I said 1353 00:48:45,560 --> 00:48:44,040 galaxies by definition usually have a 1354 00:48:47,540 --> 00:48:45,570 wide range in age every single one of 1355 00:48:49,190 --> 00:48:47,550 them looks like I'm 92 so not only do 1356 00:48:50,270 --> 00:48:49,200 they all look exactly like each 1357 00:48:52,370 --> 00:48:50,280 there - first order you know it's at 1358 00:48:53,750 --> 00:48:52,380 least by I so this was kind of 1359 00:48:56,030 --> 00:48:53,760 astonishing but it's a pretty good 1360 00:48:57,320 --> 00:48:56,040 support for this theory of what's 1361 00:48:59,120 --> 00:48:57,330 happening to missing satellites we've 1362 00:49:01,700 --> 00:48:59,130 known about these galaxies for decades 1363 00:49:03,650 --> 00:49:01,710 that form a wide range of stars or wide 1364 00:49:05,600 --> 00:49:03,660 range ages but the theory of the missing 1365 00:49:07,370 --> 00:49:05,610 satellites you know why we don't find 1366 00:49:09,140 --> 00:49:07,380 them is that most of them never form 1367 00:49:10,940 --> 00:49:09,150 stars at all and between those two 1368 00:49:12,230 --> 00:49:10,950 categories the ones that been forming 1369 00:49:14,060 --> 00:49:12,240 stars forever the ones that never form 1370 00:49:16,460 --> 00:49:14,070 stars at all should be this transition 1371 00:49:18,020 --> 00:49:16,470 group of galaxies that just formed old 1372 00:49:19,190 --> 00:49:18,030 stars and then we're snuffed out in the 1373 00:49:20,900 --> 00:49:19,200 early universe and that's what this is 1374 00:49:22,910 --> 00:49:20,910 telling us these galaxies form stars 1375 00:49:24,890 --> 00:49:22,920 right around the same time m92 was 1376 00:49:27,950 --> 00:49:24,900 formed and then we're snuffed out when 1377 00:49:29,420 --> 00:49:27,960 the lights came on these are pretty 1378 00:49:31,160 --> 00:49:29,430 boring data about just show them this is 1379 00:49:33,230 --> 00:49:31,170 the Keck data we got so this is number 1380 00:49:35,750 --> 00:49:33,240 of stars versus the chemical composition 1381 00:49:37,670 --> 00:49:35,760 so four stars here this is one percent 1382 00:49:40,010 --> 00:49:37,680 of the subtler composition this is 0.1% 1383 00:49:41,690 --> 00:49:40,020 this is 0.01 percent so these are very 1384 00:49:43,270 --> 00:49:41,700 low metallicity compared to the sun and 1385 00:49:45,710 --> 00:49:43,280 this is number of stars in the galaxy 1386 00:49:47,540 --> 00:49:45,720 compared to what fraction of the solar 1387 00:49:49,610 --> 00:49:47,550 composition there is so most of the 1388 00:49:51,200 --> 00:49:49,620 stars fall between 0.1 percent and 10 1389 00:49:53,150 --> 00:49:51,210 percent of the solar composition so the 1390 00:49:54,620 --> 00:49:53,160 stars are very metal-poor they're very 1391 00:49:56,360 --> 00:49:54,630 few metals so they're born from pristine 1392 00:49:57,590 --> 00:49:56,370 gas in the early universe this is again 1393 00:50:00,380 --> 00:49:57,600 supporting evidence that these are 1394 00:50:01,700 --> 00:50:00,390 pristine ancient galaxies m92 just for 1395 00:50:04,310 --> 00:50:01,710 comparison is right here where the green 1396 00:50:05,900 --> 00:50:04,320 line is so m92 is a little less than 1% 1397 00:50:09,800 --> 00:50:05,910 the composition of the Sun it's also 1398 00:50:12,710 --> 00:50:09,810 ancient and metal-poor so just for 1399 00:50:14,840 --> 00:50:12,720 another way to compare these data these 1400 00:50:16,850 --> 00:50:14,850 are the data from Hercules I'm zooming 1401 00:50:17,990 --> 00:50:16,860 in here now on the clock so the little 1402 00:50:19,670 --> 00:50:18,000 kink right here again this brightness 1403 00:50:21,080 --> 00:50:19,680 versus color and I'm going to take the 1404 00:50:22,610 --> 00:50:21,090 data from all the other galaxies and 1405 00:50:24,380 --> 00:50:22,620 superimpose them on here just to show 1406 00:50:28,250 --> 00:50:24,390 how similar they are so this is Hercules 1407 00:50:29,360 --> 00:50:28,260 in yellow that's Leo four in green and 1408 00:50:30,290 --> 00:50:29,370 as you said well I can't really see it 1409 00:50:34,790 --> 00:50:30,300 that well to us they're right on top of 1410 00:50:37,610 --> 00:50:34,800 each other that's CVN - and purple that 1411 00:50:40,310 --> 00:50:37,620 sort some major one in blue that's 1412 00:50:42,350 --> 00:50:40,320 bootys one in red and that's cone barren 1413 00:50:43,760 --> 00:50:42,360 brown so if you put all these galaxies 1414 00:50:45,500 --> 00:50:43,770 in the same reference frame their data 1415 00:50:47,240 --> 00:50:45,510 fall right on top of each other these 1416 00:50:49,220 --> 00:50:47,250 are six satellite galaxies of the Milky 1417 00:50:51,170 --> 00:50:49,230 Way all at different distances from the 1418 00:50:52,940 --> 00:50:51,180 Milky Way all different parts of the sky 1419 00:50:55,370 --> 00:50:52,950 and they all look exactly the same to 1420 00:50:57,320 --> 00:50:55,380 the eye so that implies some kind of 1421 00:50:58,880 --> 00:50:57,330 global influence effected all of them 1422 00:51:00,440 --> 00:50:58,890 and there's a lot of things going on 1423 00:51:01,940 --> 00:51:00,450 with galaxies form supernovae blow off 1424 00:51:03,080 --> 00:51:01,950 all the gas out of the stars new 1425 00:51:04,940 --> 00:51:03,090 generations of stars are born 1426 00:51:07,040 --> 00:51:04,950 it's a chaotic process but something 1427 00:51:08,690 --> 00:51:07,050 synchronized the star formation in all 1428 00:51:11,000 --> 00:51:08,700 six of these galaxies to a very high 1429 00:51:12,170 --> 00:51:11,010 degree and one possible thing that's 1430 00:51:13,370 --> 00:51:12,180 obvious here after you've heard the 1431 00:51:14,510 --> 00:51:13,380 pitch in the beginning is that it was 1432 00:51:15,860 --> 00:51:14,520 Rihanna's ation in the universe that 1433 00:51:18,470 --> 00:51:15,870 would be a global influence that 1434 00:51:20,300 --> 00:51:18,480 affected all the galaxies this is where 1435 00:51:21,890 --> 00:51:20,310 theory tells us the star should fall if 1436 00:51:23,450 --> 00:51:21,900 all the stars were between 12 and 13 1437 00:51:25,190 --> 00:51:23,460 billion years old they would fall on 1438 00:51:26,960 --> 00:51:25,200 this great curve here which is a good 1439 00:51:28,160 --> 00:51:26,970 match to the data the data spread out a 1440 00:51:29,900 --> 00:51:28,170 little bit more down here because there 1441 00:51:31,310 --> 00:51:29,910 are a little noisier as you go faint but 1442 00:51:35,720 --> 00:51:31,320 this is where the stars would have been 1443 00:51:36,590 --> 00:51:35,730 born right along this curve so just to 1444 00:51:38,690 --> 00:51:36,600 show you now a little more 1445 00:51:42,170 --> 00:51:38,700 quantitatively this is the zoom in now 1446 00:51:43,820 --> 00:51:42,180 on the clock for Hercules and the 1447 00:51:45,020 --> 00:51:43,830 theoretical prediction a random draw on 1448 00:51:46,580 --> 00:51:45,030 the theoretical prediction of where the 1449 00:51:48,260 --> 00:51:46,590 star should fall so one of these panels 1450 00:51:49,820 --> 00:51:48,270 is the data one is the model I won't 1451 00:51:51,320 --> 00:51:49,830 make you guess which one is which but 1452 00:51:53,270 --> 00:51:51,330 you can see the model and the data look 1453 00:51:54,950 --> 00:51:53,280 very similar the green curve is there 92 1454 00:51:58,280 --> 00:51:54,960 again just for comparison so that's 1455 00:52:01,610 --> 00:51:58,290 Hercules ones data ones the model that's 1456 00:52:03,020 --> 00:52:01,620 all six of the galaxies so in one panel 1457 00:52:04,160 --> 00:52:03,030 I'm showing you the theoretical 1458 00:52:05,630 --> 00:52:04,170 prediction for how the Stars should be 1459 00:52:06,950 --> 00:52:05,640 scattered around a diagram like this and 1460 00:52:08,840 --> 00:52:06,960 other ones the real data from Hubble and 1461 00:52:10,340 --> 00:52:08,850 each panel here they look very similar 1462 00:52:12,980 --> 00:52:10,350 right the distribution of stars is very 1463 00:52:14,510 --> 00:52:12,990 similar in each case and so what is in 1464 00:52:17,840 --> 00:52:14,520 each case is the models on the right and 1465 00:52:19,310 --> 00:52:17,850 the data on the left and the theoretical 1466 00:52:20,870 --> 00:52:19,320 prediction for where the stars ripple in 1467 00:52:23,270 --> 00:52:20,880 this diagram matches the data very well 1468 00:52:24,770 --> 00:52:23,280 I can show it this way to the grey 1469 00:52:26,900 --> 00:52:24,780 shading here is where the month the 1470 00:52:28,400 --> 00:52:26,910 theory says the star should fall and the 1471 00:52:30,050 --> 00:52:28,410 other points are where the stars do fall 1472 00:52:32,540 --> 00:52:30,060 and there's excellent agreement in all 1473 00:52:34,130 --> 00:52:32,550 six galaxies so this really tells us 1474 00:52:35,480 --> 00:52:34,140 that these are fossil galaxies now it 1475 00:52:37,160 --> 00:52:35,490 may not be true that the reorganization 1476 00:52:40,190 --> 00:52:37,170 of the universe is what made them old 1477 00:52:41,810 --> 00:52:40,200 but we were testing that theory we said 1478 00:52:43,190 --> 00:52:41,820 if there are ancient fossil galaxies 1479 00:52:44,810 --> 00:52:43,200 these would be excellent candidates for 1480 00:52:45,920 --> 00:52:44,820 being fossil galaxies we looked at them 1481 00:52:47,300 --> 00:52:45,930 closely with Hubble and they do seem 1482 00:52:49,100 --> 00:52:47,310 like they're very pristine and they're 1483 00:52:50,690 --> 00:52:49,110 metallicity and they're very very old 1484 00:52:52,970 --> 00:52:50,700 they're about 13 billion years old the 1485 00:52:54,320 --> 00:52:52,980 average age in each of these fits here 1486 00:52:56,060 --> 00:52:54,330 this is thirteen point three billion 1487 00:52:57,620 --> 00:52:56,070 years old thirteen point six billion 1488 00:52:58,820 --> 00:52:57,630 years old this is thirteen point nine 1489 00:52:59,960 --> 00:52:58,830 billion years old and I know some of 1490 00:53:00,800 --> 00:52:59,970 you're going to go wait a minute Frank a 1491 00:53:02,480 --> 00:53:00,810 little while ago to start my the 1492 00:53:04,250 --> 00:53:02,490 universe is only 13.8 billion years old 1493 00:53:06,290 --> 00:53:04,260 there's about half a billion years of 1494 00:53:08,270 --> 00:53:06,300 uncertainty and these fits do to the 1495 00:53:09,200 --> 00:53:08,280 models so it's consistent with the age 1496 00:53:10,430 --> 00:53:09,210 of the universe it's not like we're 1497 00:53:12,290 --> 00:53:10,440 saying this galaxy is older than the 1498 00:53:13,940 --> 00:53:12,300 universe but within the uncertainties 1499 00:53:14,870 --> 00:53:13,950 these galaxies were all born right after 1500 00:53:16,730 --> 00:53:14,880 the Big Bang 1501 00:53:18,560 --> 00:53:16,740 this one's 13 point 1 billion 1502 00:53:20,770 --> 00:53:18,570 years old 13 point 1 billion years old 1503 00:53:23,090 --> 00:53:20,780 12 point 7 billion years old on average 1504 00:53:25,130 --> 00:53:23,100 so these are the oldest known galaxies 1505 00:53:26,960 --> 00:53:25,140 these 6 use the only galaxies where 1506 00:53:29,540 --> 00:53:26,970 we've measured ages to this accuracy and 1507 00:53:33,410 --> 00:53:29,550 all of them are older than any galaxy 1508 00:53:34,370 --> 00:53:33,420 we've ever measured before this is 1509 00:53:36,530 --> 00:53:34,380 another way of showing the same thing 1510 00:53:39,350 --> 00:53:36,540 this is a fraction of stars born in the 1511 00:53:40,790 --> 00:53:39,360 galaxy versus time on the x axis so what 1512 00:53:42,560 --> 00:53:40,800 happens here so this is looking back in 1513 00:53:45,050 --> 00:53:42,570 time to the early universe 14 billion 1514 00:53:47,300 --> 00:53:45,060 years ago or so and star formation 1515 00:53:49,220 --> 00:53:47,310 starts very quickly 80% of the stars are 1516 00:53:51,350 --> 00:53:49,230 formed in the very first billion years 1517 00:53:52,850 --> 00:53:51,360 and then they kind of tapers off and 1518 00:53:54,530 --> 00:53:52,860 there's the width here is just the 1519 00:53:55,940 --> 00:53:54,540 uncertainty in the model so this would 1520 00:53:58,280 --> 00:53:55,950 be a narrow curve of our models were 1521 00:53:59,600 --> 00:53:58,290 better but so the star creation comes on 1522 00:54:01,640 --> 00:53:59,610 very suddenly and then this little tail 1523 00:54:03,500 --> 00:54:01,650 as realization starts to shut things 1524 00:54:05,030 --> 00:54:03,510 down in these galaxies so this is the 1525 00:54:07,070 --> 00:54:05,040 this is a fit to the data for Hercules 1526 00:54:08,450 --> 00:54:07,080 this is what it looks like for all six 1527 00:54:10,130 --> 00:54:08,460 galaxies the star form and they all look 1528 00:54:11,840 --> 00:54:10,140 very similar star formation comes on 1529 00:54:13,520 --> 00:54:11,850 very rapidly if none of the stars are 1530 00:54:15,290 --> 00:54:13,530 formed right after the Big Bang and then 1531 00:54:16,609 --> 00:54:15,300 there's a little tail going on for a few 1532 00:54:18,170 --> 00:54:16,619 billion years afterwards as it the 1533 00:54:22,599 --> 00:54:18,180 realisation the universe shuts off the 1534 00:54:24,590 --> 00:54:22,609 galaxies and their stars so 1535 00:54:25,730 --> 00:54:24,600 unfortunately for where we live or maybe 1536 00:54:27,349 --> 00:54:25,740 fortunately maybe it wouldn't be such a 1537 00:54:29,030 --> 00:54:27,359 great place to live we live in kind of a 1538 00:54:30,980 --> 00:54:29,040 cosmological backwater there's not a lot 1539 00:54:33,349 --> 00:54:30,990 going on in the local group so this is a 1540 00:54:35,270 --> 00:54:33,359 box here showing us part of the local 1541 00:54:37,070 --> 00:54:35,280 universe 80 million light years on aside 1542 00:54:39,260 --> 00:54:37,080 and the kind of work I'm talking about 1543 00:54:42,050 --> 00:54:39,270 here where you can use Hubble to measure 1544 00:54:43,010 --> 00:54:42,060 ages of stars very very accurately there 1545 00:54:44,870 --> 00:54:43,020 are a lot of ways to measure stellar 1546 00:54:46,670 --> 00:54:44,880 ages that you could do less accurately 1547 00:54:48,050 --> 00:54:46,680 you can do them far away but for doing 1548 00:54:50,000 --> 00:54:48,060 really accurate ages you can only do it 1549 00:54:51,650 --> 00:54:50,010 relatively nearby and Hubble can do this 1550 00:54:53,690 --> 00:54:51,660 kind of work in this yellow sphere right 1551 00:54:54,980 --> 00:54:53,700 here so that's where we can do the kind 1552 00:54:56,840 --> 00:54:54,990 of work I'm talking about right now and 1553 00:54:57,770 --> 00:54:56,850 it's not a really interesting patch of 1554 00:55:00,620 --> 00:54:57,780 the universe where we live unfortunately 1555 00:55:02,210 --> 00:55:00,630 so the symbols here these paperclip 1556 00:55:03,260 --> 00:55:02,220 looking things that I drew here is my 1557 00:55:05,300 --> 00:55:03,270 lame attempt to make a spiral galaxy 1558 00:55:06,650 --> 00:55:05,310 these are giant spiral galaxies the 1559 00:55:08,930 --> 00:55:06,660 Milky Way's right here at the center 1560 00:55:11,180 --> 00:55:08,940 Andromeda is our only other nearby giant 1561 00:55:12,770 --> 00:55:11,190 spiral these big red things are 1562 00:55:14,240 --> 00:55:12,780 elliptical galaxies giant elliptical 1563 00:55:15,500 --> 00:55:14,250 galaxies and the little brown dots are 1564 00:55:17,330 --> 00:55:15,510 dwarf galaxies like I've been talking 1565 00:55:18,859 --> 00:55:17,340 about tonight so we live in kind of a 1566 00:55:20,359 --> 00:55:18,869 boring part of the universe it's out in 1567 00:55:22,310 --> 00:55:20,369 the boonies there's not a lot going on 1568 00:55:24,560 --> 00:55:22,320 here it's the Milky Way Andromeda and a 1569 00:55:27,290 --> 00:55:24,570 few dozens Dorf galaxies and Hubble can 1570 00:55:29,120 --> 00:55:27,300 measure the ages of these galaxies the 1571 00:55:30,470 --> 00:55:29,130 James Webb Space Telescope is launching 1572 00:55:31,849 --> 00:55:30,480 in 2018 1573 00:55:33,200 --> 00:55:31,859 it could do the kind of work I'm talking 1574 00:55:34,880 --> 00:55:33,210 about tonight and volume three times 1575 00:55:36,319 --> 00:55:34,890 larger so it gets a lot more dwarf 1576 00:55:38,150 --> 00:55:36,329 galaxies who starts to get to the spiral 1577 00:55:39,890 --> 00:55:38,160 galaxy that's not what it was built for 1578 00:55:41,390 --> 00:55:39,900 though it looks in the infrared it's got 1579 00:55:42,920 --> 00:55:41,400 a much bigger mirror it's going to 1580 00:55:44,599 --> 00:55:42,930 measure the ages of galaxies by looking 1581 00:55:46,370 --> 00:55:44,609 directly back in time at high redshift 1582 00:55:48,500 --> 00:55:46,380 so you know if you look very far away 1583 00:55:49,790 --> 00:55:48,510 you're looking in time so James Webb is 1584 00:55:51,620 --> 00:55:49,800 going to look at the most distant 1585 00:55:53,120 --> 00:55:51,630 galaxies and observe them evolving 1586 00:55:53,900 --> 00:55:53,130 directly it's not going to do the kind 1587 00:55:55,670 --> 00:55:53,910 of stuff I'm talking about tonight 1588 00:55:56,750 --> 00:55:55,680 primarily but it will do some of that 1589 00:55:59,660 --> 00:55:56,760 kind of work and it could do it a little 1590 00:56:01,579 --> 00:55:59,670 better than Hubble folks are also 1591 00:56:02,990 --> 00:56:01,589 looking at building much bigger versions 1592 00:56:04,940 --> 00:56:03,000 of Hubble's this is an active thing 1593 00:56:06,109 --> 00:56:04,950 going on right now there's a lot of 1594 00:56:07,760 --> 00:56:06,119 folks looking to see what are the next 1595 00:56:09,380 --> 00:56:07,770 big NASA missions in the next couple 1596 00:56:11,180 --> 00:56:09,390 decades and people are talking about 1597 00:56:12,530 --> 00:56:11,190 building a UV optical telescope like 1598 00:56:15,440 --> 00:56:12,540 Hubble that it would have an 8 meter 1599 00:56:17,990 --> 00:56:15,450 mirror so Hubble's got a two point four 1600 00:56:19,490 --> 00:56:18,000 meter mirror people are looking at an 8 1601 00:56:21,680 --> 00:56:19,500 meter mirror that would get out of our 1602 00:56:23,150 --> 00:56:21,690 little you know middle of nowhere patch 1603 00:56:25,310 --> 00:56:23,160 of the universe you could start doing 1604 00:56:26,810 --> 00:56:25,320 this kind of work in spiral galaxies out 1605 00:56:28,250 --> 00:56:26,820 in the nearest towns you can actually 1606 00:56:30,560 --> 00:56:28,260 pick up an elliptical galaxy and lots of 1607 00:56:32,060 --> 00:56:30,570 other types of galaxies there are folks 1608 00:56:33,560 --> 00:56:32,070 who are really ambitious who are talking 1609 00:56:35,480 --> 00:56:33,570 about building a 16 meter version or 1610 00:56:36,980 --> 00:56:35,490 Hubble and this is really something that 1611 00:56:38,569 --> 00:56:36,990 people are looking at right now the 1612 00:56:40,520 --> 00:56:38,579 primary motivation for this is to look 1613 00:56:42,020 --> 00:56:40,530 for life around other stars so this is 1614 00:56:43,550 --> 00:56:42,030 the kind of telescope you need if you 1615 00:56:45,470 --> 00:56:43,560 want to be able to detect life directly 1616 00:56:46,550 --> 00:56:45,480 on planets orbiting other stars and if 1617 00:56:47,630 --> 00:56:46,560 you're going to build such a telescope 1618 00:56:49,190 --> 00:56:47,640 people can use your further stuff too 1619 00:56:50,180 --> 00:56:49,200 and people like me out the light looking 1620 00:56:51,650 --> 00:56:50,190 for life around other stars it's 1621 00:56:53,599 --> 00:56:51,660 obviously very exciting I measure the 1622 00:56:55,430 --> 00:56:53,609 ages of stars you could do what I'm 1623 00:56:56,630 --> 00:56:55,440 talking about tonight in this volume of 1624 00:56:58,579 --> 00:56:56,640 the universe and that would be a true 1625 00:57:00,290 --> 00:56:58,589 census of the local universe you get 1626 00:57:02,030 --> 00:57:00,300 lots of giant elliptical galaxies these 1627 00:57:03,470 --> 00:57:02,040 red things you get tons of spiral 1628 00:57:05,240 --> 00:57:03,480 galaxies many more hundreds of dwarf 1629 00:57:07,190 --> 00:57:05,250 galaxies you could really get a sense of 1630 00:57:08,660 --> 00:57:07,200 how the universe has formed it stars in 1631 00:57:10,220 --> 00:57:08,670 the nearby University of that kind of 1632 00:57:11,480 --> 00:57:10,230 telescope I probably would not get a 1633 00:57:12,559 --> 00:57:11,490 gigantic fraction of the time most the 1634 00:57:14,240 --> 00:57:12,569 time it will be looking for life front 1635 00:57:16,880 --> 00:57:14,250 other stars but you could get some time 1636 00:57:18,589 --> 00:57:16,890 doing this type of work so this is the 1637 00:57:19,420 --> 00:57:18,599 Hubble Space Telescope and low-earth 1638 00:57:21,470 --> 00:57:19,430 orbit 1639 00:57:23,599 --> 00:57:21,480 most of our carbon torment tonight comes 1640 00:57:25,520 --> 00:57:23,609 from Hubble also comes from Keck I 1641 00:57:27,140 --> 00:57:25,530 worked previously up until a few months 1642 00:57:29,450 --> 00:57:27,150 ago on the James Webb Space Telescope 1643 00:57:30,589 --> 00:57:29,460 for the last eight years so I'll just 1644 00:57:32,450 --> 00:57:30,599 give you a little update on that this is 1645 00:57:34,190 --> 00:57:32,460 James Webb it has unlike a two point 1646 00:57:36,230 --> 00:57:34,200 four meter mirror it has a six and a 1647 00:57:38,270 --> 00:57:36,240 half meter mirror coated in gold it's a 1648 00:57:39,859 --> 00:57:38,280 beryllium mirror and then just to give 1649 00:57:41,990 --> 00:57:39,869 you a sense of scale this is the light 1650 00:57:43,460 --> 00:57:42,000 shield this is the Sun shield it's about 1651 00:57:45,109 --> 00:57:43,470 the size of a tennis court 1652 00:57:47,359 --> 00:57:45,119 made of a material similar to like candy 1653 00:57:48,890 --> 00:57:47,369 wrappers it's got five layers here keeps 1654 00:57:50,690 --> 00:57:48,900 the instruments in the telescope in the 1655 00:57:54,130 --> 00:57:50,700 shade while it's orbiting out around the 1656 00:57:56,660 --> 00:57:54,140 Sun we're launching that in October 2018 1657 00:57:58,220 --> 00:57:56,670 these are the main science goals of 1658 00:57:59,810 --> 00:57:58,230 James Webb so it's going to look at the 1659 00:58:01,190 --> 00:57:59,820 first galaxies in the universe so again 1660 00:58:02,480 --> 00:58:01,200 it will be measuring the evolution of 1661 00:58:03,920 --> 00:58:02,490 galaxies but in a very different way 1662 00:58:06,080 --> 00:58:03,930 it's going to look directly back in time 1663 00:58:07,760 --> 00:58:06,090 of the most distant galaxies it's going 1664 00:58:09,770 --> 00:58:07,770 to watch over that cosmic time how 1665 00:58:11,330 --> 00:58:09,780 galaxies evolve because it's looking in 1666 00:58:13,940 --> 00:58:11,340 the infrared it can peer through dust 1667 00:58:15,560 --> 00:58:13,950 and gas to see stars and Galant planets 1668 00:58:17,420 --> 00:58:15,570 being born and it's gonna be able to 1669 00:58:20,650 --> 00:58:17,430 look for the origin of life so these are 1670 00:58:23,660 --> 00:58:20,660 the main science themes of James Webb 1671 00:58:25,700 --> 00:58:23,670 just for comparison Hubble is in 1672 00:58:26,930 --> 00:58:25,710 low-earth orbit you know on this scale 1673 00:58:28,190 --> 00:58:26,940 you wouldn't be able to see how far away 1674 00:58:29,990 --> 00:58:28,200 from Earth it is it'd be orbiting right 1675 00:58:32,089 --> 00:58:30,000 there James Webb is going to go out here 1676 00:58:33,530 --> 00:58:32,099 to a point we called Lagrange two it's 1677 00:58:37,640 --> 00:58:33,540 four times further away than the moon 1678 00:58:38,810 --> 00:58:37,650 one and a half kilometers away and then 1679 00:58:43,220 --> 00:58:38,820 just here's a comparison of the 1680 00:58:45,620 --> 00:58:43,230 telescope sizes here's a person 1.75 1681 00:58:47,470 --> 00:58:45,630 meters tall here's Hubble's meter 2.4 1682 00:58:52,160 --> 00:58:47,480 meters tall and here's James Webb 1683 00:58:54,560 --> 00:58:52,170 six-and-a-half meters tall in 18 1684 00:58:56,270 --> 00:58:54,570 segments that's ground testing down a 1685 00:58:57,829 --> 00:58:56,280 NASA of some of the mirror segments 1686 00:58:58,910 --> 00:58:57,839 again coated in gold people freaked out 1687 00:59:00,620 --> 00:58:58,920 a little bit you say the mirror is made 1688 00:59:02,690 --> 00:59:00,630 of gold oh my god that's it's wasting so 1689 00:59:04,400 --> 00:59:02,700 much money the whole mirror has about 1690 00:59:05,839 --> 00:59:04,410 this much gold on the coating of it okay 1691 00:59:10,339 --> 00:59:05,849 so just for comparison so it's a very 1692 00:59:12,200 --> 00:59:10,349 thin layer on the surface here are the 1693 00:59:13,730 --> 00:59:12,210 instruments so we were testing the 1694 00:59:15,500 --> 00:59:13,740 instruments individually at different 1695 00:59:16,760 --> 00:59:15,510 locations around the world up until a 1696 00:59:18,140 --> 00:59:16,770 few years ago and then we started 1697 00:59:19,520 --> 00:59:18,150 integrating them into the integrated 1698 00:59:21,410 --> 00:59:19,530 science instrument module that got 1699 00:59:23,510 --> 00:59:21,420 tested last year Goddard so it's near 1700 00:59:25,099 --> 00:59:23,520 cam which is a near infrared camera Miri 1701 00:59:27,500 --> 00:59:25,109 which is a mid infrared instrument also 1702 00:59:29,480 --> 00:59:27,510 camera and a spectrograph near spec and 1703 00:59:32,300 --> 00:59:29,490 your infrared spectrograph and near us 1704 00:59:33,950 --> 00:59:32,310 also a near infrared camera hence 1705 00:59:38,120 --> 00:59:33,960 spectrograph specifically designed for 1706 00:59:39,710 --> 00:59:38,130 exoplanet searches and here's the test 1707 00:59:41,150 --> 00:59:39,720 chamber at Goddard where we were just 1708 00:59:44,950 --> 00:59:41,160 testing we wrapped up testing of the 1709 00:59:47,599 --> 00:59:44,960 instruments this last year in February 1710 00:59:48,980 --> 00:59:47,609 this is the chamber that will be used to 1711 00:59:51,680 --> 00:59:48,990 test the instruments and the mirror 1712 00:59:53,030 --> 00:59:51,690 together next year in April this is the 1713 00:59:54,589 --> 00:59:53,040 same chamber that was used for the 1714 00:59:56,180 --> 00:59:54,599 Apollo Lunar Module 1715 00:59:56,839 --> 00:59:56,190 I walked around inside this a few years 1716 00:59:57,890 --> 00:59:56,849 ago before they 1717 00:59:59,299 --> 00:59:57,900 started cleaning it out and for the 1718 01:00:00,710 --> 00:59:59,309 testing I have to say it's crazy 1719 01:00:02,329 --> 01:00:00,720 impressive and those are people standing 1720 01:00:03,799 --> 01:00:02,339 here so you walk around inside the 1721 01:00:05,569 --> 01:00:03,809 scaffolding it's the same chamber those 1722 01:00:07,009 --> 01:00:05,579 used to test the Apollo missions and 1723 01:00:10,099 --> 01:00:07,019 we'll it's at Johnson Space Center will 1724 01:00:11,539 --> 01:00:10,109 be starting testing there next year and 1725 01:00:12,710 --> 01:00:11,549 that's what it look like so James Webb 1726 01:00:14,690 --> 01:00:12,720 will be what we call the cup up 1727 01:00:16,160 --> 01:00:14,700 configuration so the mirror is facing up 1728 01:00:17,839 --> 01:00:16,170 the instruments are sitting here facing 1729 01:00:19,339 --> 01:00:17,849 down and we'll do some simulations of 1730 01:00:22,940 --> 01:00:19,349 the conditions in space to test it 1731 01:00:24,979 --> 01:00:22,950 before we launch it so just to summarize 1732 01:00:26,960 --> 01:00:24,989 the ultra faint dwarf galaxies are 1733 01:00:28,789 --> 01:00:26,970 extremely metal-poor some of the most 1734 01:00:30,410 --> 01:00:28,799 metal-poor stars in the universe that we 1735 01:00:31,640 --> 01:00:30,420 know about are found in these ultra 1736 01:00:33,049 --> 01:00:31,650 faint dwarf galaxies and their chemical 1737 01:00:34,640 --> 01:00:33,059 abundances and most of the stars are a 1738 01:00:36,769 --> 01:00:34,650 tenth of a percent to one percent of 1739 01:00:38,049 --> 01:00:36,779 those we found in the Sun the ultra 1740 01:00:40,880 --> 01:00:38,059 faint dwarf galaxies are ancient 1741 01:00:42,349 --> 01:00:40,890 three-quarters of the stars formed their 1742 01:00:44,210 --> 01:00:42,359 star three-quarters of the stars were 1743 01:00:46,400 --> 01:00:44,220 formed more than 13 billion years ago 1744 01:00:48,769 --> 01:00:46,410 so these galaxies are truly ancient 1745 01:00:50,210 --> 01:00:48,779 there are known as far as we can tell 1746 01:00:51,559 --> 01:00:50,220 intermediate stars are nothing really 1747 01:00:53,479 --> 01:00:51,569 younger than 10 billion years old on 1748 01:00:54,799 --> 01:00:53,489 these stars and that's very distinct 1749 01:00:56,150 --> 01:00:54,809 from pretty much not only the classical 1750 01:00:57,769 --> 01:00:56,160 dwarf galaxies every other galaxies that 1751 01:01:00,859 --> 01:00:57,779 ever been studied most galaxies have a 1752 01:01:02,150 --> 01:01:00,869 young stars and old stars star formation 1753 01:01:03,589 --> 01:01:02,160 appears to be synchronised in these 1754 01:01:04,999 --> 01:01:03,599 objects even though there's six 1755 01:01:06,859 --> 01:01:05,009 different galaxies spread out on the sky 1756 01:01:07,849 --> 01:01:06,869 they all have pretty much the same star 1757 01:01:09,049 --> 01:01:07,859 formation history it's like a guillotine 1758 01:01:10,219 --> 01:01:09,059 came along and shut off the star 1759 01:01:12,019 --> 01:01:10,229 information in all these at the same 1760 01:01:13,339 --> 01:01:12,029 time and that's what you would expect if 1761 01:01:14,779 --> 01:01:13,349 they were all snuffed out by the 1762 01:01:16,640 --> 01:01:14,789 reorganization of the universe shortly 1763 01:01:18,440 --> 01:01:16,650 after the Big Bang and this is 1764 01:01:19,999 --> 01:01:18,450 consistent with pollutions that are 1765 01:01:22,099 --> 01:01:20,009 opposed to the missing satellite problem 1766 01:01:23,690 --> 01:01:22,109 most of the missing satellites are there 1767 01:01:25,819 --> 01:01:23,700 but they just have fewer know stars so 1768 01:01:28,130 --> 01:01:25,829 we can't see them thanks and I'll show 1769 01:01:29,150 --> 01:01:28,140 this video of the j2 ST deployment in 1770 01:02:05,749 --> 01:01:29,160 two years while I answer questions 1771 01:02:10,630 --> 01:02:07,569 so dark matters just matter that's not 1772 01:02:14,059 --> 01:02:10,640 luminous so I mean dark matter is it 1773 01:02:15,529 --> 01:02:14,069 right but people are trying to figure 1774 01:02:16,910 --> 01:02:15,539 out what dark matter is so we don't 1775 01:02:18,559 --> 01:02:16,920 really have a good handle on what dark 1776 01:02:19,910 --> 01:02:18,569 matter is people are searching for there 1777 01:02:21,859 --> 01:02:19,920 and we know it's there from its 1778 01:02:23,359 --> 01:02:21,869 gravitational effects but you can't 1779 01:02:32,959 --> 01:02:23,369 observe it directly you just see it's in 1780 01:02:34,130 --> 01:02:32,969 dirt you know well in these galaxies 1781 01:02:35,719 --> 01:02:34,140 they're dark but we call it dark matter 1782 01:02:37,249 --> 01:02:35,729 dominated so the ones I showed you 1783 01:02:38,959 --> 01:02:37,259 tonight there's very little like so 1784 01:02:40,219 --> 01:02:38,969 there's only a few stars and then you 1785 01:02:41,779 --> 01:02:40,229 know there's dark matter there because 1786 01:02:42,829 --> 01:02:41,789 of the orbits of those stars but then 1787 01:02:44,120 --> 01:02:42,839 there are other clumps of dark matter 1788 01:02:46,219 --> 01:02:44,130 out there where there's no stars in them 1789 01:02:53,209 --> 01:02:46,229 at all we just infer their presence from 1790 01:02:55,670 --> 01:02:53,219 from the gravitational pull the clumping 1791 01:02:56,569 --> 01:02:55,680 looks very similar in theory to that 1792 01:02:57,769 --> 01:02:56,579 simulation I showed in the beginning 1793 01:02:59,630 --> 01:02:57,779 with all the hundreds of little blue 1794 01:03:00,680 --> 01:02:59,640 points around the Milky Way but people 1795 01:03:03,890 --> 01:03:00,690 have been searching for dark matter 1796 01:03:05,420 --> 01:03:03,900 pretty strenuous ly and you know not 1797 01:03:07,009 --> 01:03:05,430 finding a lot of it so that's the 1798 01:03:08,930 --> 01:03:07,019 theoretical prediction of how it clumps 1799 01:03:10,069 --> 01:03:08,940 you know but how it actually clumps we 1800 01:03:20,259 --> 01:03:10,079 don't have a good handle on yet because 1801 01:03:24,439 --> 01:03:23,029 yeah B since we can't observe the clumps 1802 01:03:25,579 --> 01:03:24,449 that have no stars we really can't 1803 01:03:27,079 --> 01:03:25,589 observe those directly so what I'm 1804 01:03:29,479 --> 01:03:27,089 looking at here are the ones that just 1805 01:03:31,910 --> 01:03:29,489 formed a few stars and that's that gives 1806 01:03:33,049 --> 01:03:31,920 us credence to the theory that why the 1807 01:03:34,729 --> 01:03:33,059 missing silence are there would be great 1808 01:03:36,400 --> 01:03:34,739 if we actually observe those hundreds of 1809 01:03:42,290 --> 01:03:36,410 clumps that we don't have any stars in 1810 01:03:46,680 --> 01:03:45,120 so the oldest stars in those galaxies go 1811 01:03:48,210 --> 01:03:46,690 back to the Big Bang within the error 1812 01:03:49,770 --> 01:03:48,220 bars so back to the thirteen half 1813 01:03:51,030 --> 01:03:49,780 billion years old or so so that was the 1814 01:03:52,470 --> 01:03:51,040 image that's on the David Bowie album 1815 01:03:54,120 --> 01:03:52,480 that was the goal of that program was to 1816 01:03:56,340 --> 01:03:54,130 measure the range of Ages in Andromeda 1817 01:03:58,050 --> 01:03:56,350 out and it's halo stars and so we found 1818 01:03:59,280 --> 01:03:58,060 stars over 13 1/2 million years old we 1819 01:04:00,780 --> 01:03:59,290 found stars there were just a billion 1820 01:04:03,420 --> 01:04:00,790 years old know everything in between and 1821 01:04:04,620 --> 01:04:03,430 that's the case for the Milky Way that's 1822 01:04:06,060 --> 01:04:04,630 the case for Andromeda that's the case 1823 01:04:07,590 --> 01:04:06,070 for the satellite galaxies that we've 1824 01:04:09,630 --> 01:04:07,600 known about it's these Ultra faint 1825 01:04:11,310 --> 01:04:09,640 dwarfs that only have ancient stars 1826 01:04:12,660 --> 01:04:11,320 every other galaxy we've looked at as 1827 01:04:14,940 --> 01:04:12,670 young stars only young for an astronomer 1828 01:04:17,280 --> 01:04:14,950 you know it's definitely less than 10 1829 01:04:23,460 --> 01:04:17,290 billion years old and and old stars as 1830 01:04:25,350 --> 01:04:23,470 well is that the structure the Milky Way 1831 01:04:28,290 --> 01:04:25,360 believed to have formed around ten 1832 01:04:31,320 --> 01:04:28,300 billion years ago the structure of the 1833 01:04:34,140 --> 01:04:31,330 disk of the galaxy right so some stars 1834 01:04:41,040 --> 01:04:34,150 are as well as the universe but the 1835 01:04:42,840 --> 01:04:41,050 structure itself is believed to be about 1836 01:04:44,610 --> 01:04:42,850 ten billion years old and we can see 1837 01:04:45,900 --> 01:04:44,620 that by looking at higher retro so if 1838 01:04:47,130 --> 01:04:45,910 you look at varied in the very distant 1839 01:04:48,780 --> 01:04:47,140 universe which is looking back in time 1840 01:04:50,130 --> 01:04:48,790 you can see mostly Universal smaller 1841 01:04:52,050 --> 01:04:50,140 galaxies and then they start clumping 1842 01:05:03,300 --> 01:04:52,060 together and forming more massive 1843 01:05:06,320 --> 01:05:03,310 galaxies as they merge so yeah well yeah 1844 01:05:25,110 --> 01:05:06,330 I mean there's one technical reason so 1845 01:05:26,760 --> 01:05:25,120 I'm yeah yeah right here yeah yeah I 1846 01:05:28,950 --> 01:05:26,770 mean is it Commission's commissioning on 1847 01:05:34,650 --> 01:05:28,960 James Webb last six months so it's a six 1848 01:05:36,090 --> 01:05:34,660 month process steps I mean hundreds and 1849 01:05:38,150 --> 01:05:36,100 hundreds of steps right oh so there's a 1850 01:05:44,190 --> 01:05:38,160 lot of steps different things unfurling 1851 01:05:46,440 --> 01:05:44,200 the folks yeah so it'll commit it'll 1852 01:05:48,420 --> 01:05:46,450 it'll be deploying on its way to the 1853 01:05:49,680 --> 01:05:48,430 Lagrangian right so and then we'll be 1854 01:05:50,730 --> 01:05:49,690 able monitoring it the whole time and 1855 01:05:51,830 --> 01:05:50,740 there's some things you don't want to do 1856 01:05:53,030 --> 01:05:51,840 until you tell 1857 01:05:55,310 --> 01:05:53,040 hope is cooled significantly it's 1858 01:05:57,230 --> 01:05:55,320 cooling off on the way there there's a 1859 01:05:58,460 --> 01:05:57,240 careful orchestration of events there as 1860 01:05:59,750 --> 01:05:58,470 well so you don't have like Isis 1861 01:06:01,310 --> 01:05:59,760 accumulating on the instruments and 1862 01:06:03,020 --> 01:06:01,320 their optics and so forth so it's a very 1863 01:06:04,760 --> 01:06:03,030 careful choreographic series of events 1864 01:06:06,020 --> 01:06:04,770 as it goes out to the crunch - and then 1865 01:06:09,260 --> 01:06:06,030 after the first six months is over we 1866 01:06:29,299 --> 01:06:09,270 start doing science that's the plan all 1867 01:06:33,870 --> 01:06:32,069 yeah so we use it because this that's a 1868 01:06:35,849 --> 01:06:33,880 very good explanation so the James Webb 1869 01:06:37,439 --> 01:06:35,859 Space Telescope works primarily in the 1870 01:06:39,509 --> 01:06:37,449 infrared at wavelengths longer than our 1871 01:06:41,219 --> 01:06:39,519 eyes work and a very good substance to 1872 01:06:44,159 --> 01:06:41,229 work with for reflectivity at those 1873 01:06:46,079 --> 01:06:44,169 wavelengths is gold right it's crazy 1874 01:06:55,039 --> 01:06:46,089 other week we in back sure okay wait 1875 01:06:59,759 --> 01:06:58,019 sure so the lights come on so when the 1876 01:07:01,439 --> 01:06:59,769 very first stars in galaxies form you 1877 01:07:03,479 --> 01:07:01,449 have these massive stars and universe 1878 01:07:05,219 --> 01:07:03,489 gets flooded with ultraviolet light so 1879 01:07:06,689 --> 01:07:05,229 it's very very energetic like x-ray 1880 01:07:08,249 --> 01:07:06,699 light as well even higher energy light 1881 01:07:09,390 --> 01:07:08,259 and what it goes it goes sweeping 1882 01:07:11,880 --> 01:07:09,400 through the universe and all this 1883 01:07:13,499 --> 01:07:11,890 neutral gas gets energized and rely on 1884 01:07:16,019 --> 01:07:13,509 eyes so basically the electrons get 1885 01:07:17,549 --> 01:07:16,029 stripped off the atoms and so that's a 1886 01:07:19,769 --> 01:07:17,559 very energetic process when the universe 1887 01:07:21,630 --> 01:07:19,779 very earlier on is much much hotter than 1888 01:07:22,799 --> 01:07:21,640 it is today today the temperature the 1889 01:07:25,469 --> 01:07:22,809 universe the Cosmic Microwave Background 1890 01:07:27,539 --> 01:07:25,479 is 2.7 Kelvin above you know so it's 1891 01:07:28,890 --> 01:07:27,549 three degrees above absolute zero back 1892 01:07:30,630 --> 01:07:28,900 in the early universe is much much 1893 01:07:31,949 --> 01:07:30,640 hotter and so what happens is this 1894 01:07:33,870 --> 01:07:31,959 energy goes sweeping through the 1895 01:07:34,949 --> 01:07:33,880 universe you have these clumps of dark 1896 01:07:36,239 --> 01:07:34,959 matter which are like little 1897 01:07:37,859 --> 01:07:36,249 gravitational wells 1898 01:07:39,509 --> 01:07:37,869 they have gas sitting there in the dark 1899 01:07:41,849 --> 01:07:39,519 with the dark matter and then this 1900 01:07:43,709 --> 01:07:41,859 energy comes sweeping through and sweeps 1901 01:07:45,870 --> 01:07:43,719 the gas out of those clumps of dark 1902 01:07:47,309 --> 01:07:45,880 matter it doesn't do that for the really 1903 01:07:48,569 --> 01:07:47,319 big clumps of dark matter so the really 1904 01:07:50,549 --> 01:07:48,579 big clumps of dark matter they don't 1905 01:07:52,499 --> 01:07:50,559 lose all their gas and also because they 1906 01:07:54,059 --> 01:07:52,509 have more gravity they react Yuma late 1907 01:07:56,130 --> 01:07:54,069 that ground quick gas and sweep it back 1908 01:07:57,890 --> 01:07:56,140 up but these small clumps of dark matter 1909 01:08:00,509 --> 01:07:57,900 the ones that don't really form stars 1910 01:08:02,849 --> 01:08:00,519 the gas is swept up and never comes back 1911 01:08:03,959 --> 01:08:02,859 and so they don't form stars and it's 1912 01:08:06,839 --> 01:08:03,969 just a clump of dark matter they've been 1913 01:08:09,209 --> 01:08:06,849 stripped of their gas so have it right 1914 01:08:31,390 --> 01:08:09,219 over here to the right you in the red 1915 01:08:37,450 --> 01:08:35,620 I find it yeah maybe you could repeat 1916 01:08:39,190 --> 01:08:37,460 one more time I'm actually not asking 1917 01:08:41,349 --> 01:08:39,200 why do we get the globular structures 1918 01:08:51,970 --> 01:08:41,359 and some some galaxies and the disk 1919 01:08:54,520 --> 01:08:51,980 structures and other galaxies so the 1920 01:08:56,079 --> 01:08:54,530 dark matters is driving the large-scale 1921 01:08:57,190 --> 01:08:56,089 structure of the universe if like I said 1922 01:08:59,170 --> 01:08:57,200 it's kind of like the scaffolding that 1923 01:09:01,090 --> 01:08:59,180 all the gas and matter in the universe 1924 01:09:03,190 --> 01:09:01,100 accretes along it and then much more 1925 01:09:05,349 --> 01:09:03,200 complex things happen on small scales 1926 01:09:07,450 --> 01:09:05,359 like like the Andromeda galaxy or the 1927 01:09:09,010 --> 01:09:07,460 Milky Way basically you have things 1928 01:09:10,780 --> 01:09:09,020 they're spinning and then they start to 1929 01:09:12,430 --> 01:09:10,790 collapse perpendicular to the direction 1930 01:09:14,079 --> 01:09:12,440 of spinning it makes a disc there's 1931 01:09:15,550 --> 01:09:14,089 still a swarm of stars kind of like a 1932 01:09:17,410 --> 01:09:15,560 bee swarm around that that's called the 1933 01:09:19,750 --> 01:09:17,420 halo so it's a very very complex 1934 01:09:21,550 --> 01:09:19,760 hydrodynamic oppresses I mean they don't 1935 01:09:23,380 --> 01:09:21,560 have a simulation new on my computer but 1936 01:09:24,820 --> 01:09:23,390 basically you have a lot of interactions 1937 01:09:26,740 --> 01:09:24,830 between the matter on the small scales 1938 01:09:28,570 --> 01:09:26,750 of a galaxy I'm galaxy is small for our 1939 01:09:30,430 --> 01:09:28,580 purposes here on the large scale of the 1940 01:09:32,230 --> 01:09:30,440 universe you have these filamentary 1941 01:09:34,090 --> 01:09:32,240 structure these filaments of dark matter 1942 01:09:35,530 --> 01:09:34,100 where everything all the matter kind of 1943 01:09:36,820 --> 01:09:35,540 collapses along those filaments and 1944 01:09:39,490 --> 01:09:36,830 we're a couple filaments come together 1945 01:09:40,780 --> 01:09:39,500 you have a galaxy form there so okay 1946 01:09:43,450 --> 01:09:40,790 Tom we've got a question from online 1947 01:09:45,340 --> 01:09:43,460 sure our ancient stars metal-poor 1948 01:09:48,099 --> 01:09:45,350 because there hasn't been a lot of star 1949 01:09:50,140 --> 01:09:48,109 recycling yet yes well ancients start if 1950 01:09:51,730 --> 01:09:50,150 you're if a star is ancient if it was 1951 01:09:54,700 --> 01:09:51,740 born in the early universe it won't have 1952 01:09:56,350 --> 01:09:54,710 many metals period then if stars are 1953 01:09:58,090 --> 01:09:56,360 born more recently they could be born 1954 01:09:59,620 --> 01:09:58,100 from pristine gas if they just happen to 1955 01:10:01,240 --> 01:09:59,630 be in a lucky patch of the universe but 1956 01:10:02,740 --> 01:10:01,250 more often than not because they've been 1957 01:10:04,720 --> 01:10:02,750 multiple generations of stars those 1958 01:10:06,220 --> 01:10:04,730 stars have pulled the oldest the stars 1959 01:10:08,020 --> 01:10:06,230 that have already blown up in supernovae 1960 01:10:09,460 --> 01:10:08,030 they've polluted the gas and then new 1961 01:10:20,800 --> 01:10:09,470 generations of stars are born they have 1962 01:10:24,530 --> 01:10:23,270 yeah I don't have opinion on it cuz I'm 1963 01:10:25,820 --> 01:10:24,540 not a theorist rep but people are still 1964 01:10:27,890 --> 01:10:25,830 arguing about it until we can actually 1965 01:10:29,419 --> 01:10:27,900 you know measure it more directly 1966 01:10:36,649 --> 01:10:29,429 there's not oh there's a lot of theories 1967 01:10:39,800 --> 01:10:36,659 out there right so yeah right here so 1968 01:10:41,689 --> 01:10:39,810 dark matters around 20-25 percent dark 1969 01:10:42,740 --> 01:10:41,699 energies around seventy percent or 1970 01:10:43,910 --> 01:10:42,750 something like that and then there's 1971 01:10:45,979 --> 01:10:43,920 just a few percent is baryonic matter 1972 01:11:01,750 --> 01:10:45,989 like you know we're made out of in what 1973 01:11:05,600 --> 01:11:03,950 because most of the matter in the 1974 01:11:15,350 --> 01:11:05,610 universe is dark so they're the biggest 1975 01:11:17,240 --> 01:11:15,360 source of gravity in the universe so not 1976 01:11:18,830 --> 01:11:17,250 that we know of in fact dark matter 1977 01:11:20,209 --> 01:11:18,840 itself doesn't we don't really even know 1978 01:11:21,830 --> 01:11:20,219 how much it interacts with normal matter 1979 01:11:23,570 --> 01:11:21,840 in fact I mean you have it we see the 1980 01:11:25,370 --> 01:11:23,580 effects of its gravity you can see the 1981 01:11:27,109 --> 01:11:25,380 motions of stars in the Milky Way are 1982 01:11:29,270 --> 01:11:27,119 moving in a way that implies there's a 1983 01:11:30,740 --> 01:11:29,280 lot more mass there than the mass of the 1984 01:11:31,970 --> 01:11:30,750 stars we can see so we know the dark 1985 01:11:34,100 --> 01:11:31,980 matter is there we know it has a 1986 01:11:35,240 --> 01:11:34,110 gravitational effect on things but other 1987 01:11:36,320 --> 01:11:35,250 than that we don't know a lot about it 1988 01:11:37,640 --> 01:11:36,330 we don't know how much it interacts with 1989 01:11:39,919 --> 01:11:37,650 itself how much it interact with other 1990 01:11:41,750 --> 01:11:39,929 matter yeah I figure to think about is 1991 01:11:44,450 --> 01:11:41,760 about eighty-five percent of the mass of 1992 01:11:46,939 --> 01:11:44,460 the gravity in the universe is dark 1993 01:11:59,709 --> 01:11:46,949 matter okay only ten to fifteen percent 1994 01:12:03,100 --> 01:12:01,390 just us it's pretty accessible and 1995 01:12:06,459 --> 01:12:03,110 stable so this is a good place to put it 1996 01:12:08,770 --> 01:12:06,469 out there we put other we oh okay sorry 1997 01:12:11,399 --> 01:12:08,780 yeah so the Lagrangian was chosen she 1998 01:12:14,620 --> 01:12:11,409 the the question was why was the 1999 01:12:16,000 --> 01:12:14,630 Lagrangian for JWST s orbit we actually 2000 01:12:17,890 --> 01:12:16,010 put a lot of satellites out there 2001 01:12:19,660 --> 01:12:17,900 because it's a relatively stable point 2002 01:12:21,250 --> 01:12:19,670 it doesn't take a lot of fuel to keep a 2003 01:12:23,140 --> 01:12:21,260 satellite in orbit around that LaGrant 2004 01:12:24,790 --> 01:12:23,150 and it's fairly accessible compared to 2005 01:12:26,200 --> 01:12:24,800 some Dettol L'Orange points which are on 2006 01:12:41,830 --> 01:12:26,210 the other side of the Sun and so forth 2007 01:12:44,290 --> 01:12:41,840 oh yeah hmm Wow there we go into space 2008 01:12:46,090 --> 01:12:44,300 they don't go swept away and forever I'm 2009 01:12:48,010 --> 01:12:46,100 saying that the gas in a local sense 2010 01:12:49,990 --> 01:12:48,020 becomes so hot that the protons 2011 01:12:51,160 --> 01:12:50,000 electrons separate but it's not like 2012 01:12:52,149 --> 01:12:51,170 they're going to different parts of the 2013 01:12:58,030 --> 01:12:52,159 universe they're all local they're 2014 01:12:59,140 --> 01:12:58,040 together and get oh well okay it's a 2015 01:13:02,680 --> 01:12:59,150 couple different things going on in 2016 01:13:04,300 --> 01:13:02,690 there so the gas gets very energized by 2017 01:13:06,970 --> 01:13:04,310 the Stars coming on so it becomes 2018 01:13:08,620 --> 01:13:06,980 ionized and then also it basically boils 2019 01:13:10,720 --> 01:13:08,630 out of the gravitational wells of these 2020 01:13:12,399 --> 01:13:10,730 Dark Matter clumps so the escape 2021 01:13:14,350 --> 01:13:12,409 velocity basically becomes such that it 2022 01:13:16,479 --> 01:13:14,360 escapes these Dark Matter clumps if the 2023 01:13:17,620 --> 01:13:16,489 Dark Matter clump is large enough the 2024 01:13:19,060 --> 01:13:17,630 gas will fall back into the 2025 01:13:21,340 --> 01:13:19,070 gravitational well and continue forming 2026 01:13:23,169 --> 01:13:21,350 stars which is what most galaxies do but 2027 01:13:24,399 --> 01:13:23,179 if it's not the gas just goes on into 2028 01:13:26,020 --> 01:13:24,409 the intergalactic medium between the 2029 01:13:27,520 --> 01:13:26,030 galaxies so there is a lot of gas out 2030 01:13:28,930 --> 01:13:27,530 there I mean one of the press releases 2031 01:13:31,120 --> 01:13:28,940 Frank talked about people even look for 2032 01:13:32,470 --> 01:13:31,130 galaxies by looking for neutral gas and 2033 01:13:41,220 --> 01:13:32,480 so forth so there's gas between the 2034 01:13:44,859 --> 01:13:43,660 it does it's no longer in those dark 2035 01:13:59,350 --> 01:13:44,869 matter clumps it gets swept out in 2036 01:14:01,209 --> 01:13:59,360 between the clumps yeah yeah I have no 2037 01:14:03,160 --> 01:14:01,219 idea off the top of my head I mean some 2038 01:14:04,750 --> 01:14:03,170 of these things some of these things you 2039 01:14:05,680 --> 01:14:04,760 know there's an economy of scale that 2040 01:14:06,970 --> 01:14:05,690 you know that people are trying to 2041 01:14:08,379 --> 01:14:06,980 leverage when they look at these future 2042 01:14:09,729 --> 01:14:08,389 missions but it would be very expensive 2043 01:14:11,589 --> 01:14:09,739 I'm not saying it would be 2044 01:14:12,970 --> 01:14:11,599 technologically trivial either we would 2045 01:14:14,080 --> 01:14:12,980 have to work very hard on it as well 2046 01:14:16,300 --> 01:14:14,090 it's not it's not like it would be a 2047 01:14:18,220 --> 01:14:16,310 piece of cake but uh but it's within the 2048 01:14:20,050 --> 01:14:18,230 grasp of today's technology you know if 2049 01:14:22,770 --> 01:14:20,060 if the money was there but it would be a 2050 01:14:26,589 --> 01:14:22,780 lot more expensive than James Webb Rahal 2051 01:14:30,250 --> 01:14:26,599 8 billion okay another question from 2052 01:14:32,560 --> 01:14:30,260 online would a 16 meter mirror telescope 2053 01:14:34,780 --> 01:14:32,570 be able to directly image low mass 2054 01:14:36,430 --> 01:14:34,790 worlds such as Earth or Mars 2055 01:14:37,870 --> 01:14:36,440 yeah that's the goal I mean depends on 2056 01:14:40,330 --> 01:14:37,880 how well separated they are from their 2057 01:14:43,120 --> 01:14:40,340 host star but if they were separated 2058 01:14:45,129 --> 01:14:43,130 enough then does that be the goal to see 2059 01:14:53,140 --> 01:14:45,139 you know habitable worlds with such a 2060 01:14:54,609 --> 01:14:53,150 telescope to directly image them yeah as 2061 01:14:55,839 --> 01:14:54,619 far as we know we don't think I mean 2062 01:14:57,280 --> 01:14:55,849 darknet we again we don't know how much 2063 01:14:58,870 --> 01:14:57,290 dark matter interacts with normal matter 2064 01:15:00,040 --> 01:14:58,880 and energy and so forth so it has a 2065 01:15:01,750 --> 01:15:00,050 gravitational effect other than that I 2066 01:15:03,160 --> 01:15:01,760 don't know a lot about dark matter you 2067 01:15:05,080 --> 01:15:03,170 know there's a lot of theories about it 2068 01:15:06,070 --> 01:15:05,090 but no mostly the realization when you 2069 01:15:08,770 --> 01:15:06,080 talk about randomization you talk about 2070 01:15:16,479 --> 01:15:08,780 the baryonic matter this gentleman over 2071 01:15:20,180 --> 01:15:18,589 so the question is how do black holes 2072 01:15:21,770 --> 01:15:20,190 interact with dark matter black holes 2073 01:15:23,629 --> 01:15:21,780 are a form of dark matter we don't think 2074 01:15:25,250 --> 01:15:23,639 they make up a large part of the budget 2075 01:15:26,899 --> 01:15:25,260 of dark matter but they interact 2076 01:15:29,720 --> 01:15:26,909 gravitationally with dark matter as well 2077 01:15:31,129 --> 01:15:29,730 so you know dark matter can interact 2078 01:15:32,479 --> 01:15:31,139 with a black hole gravitationally other 2079 01:15:34,879 --> 01:15:32,489 than that we don't know how dark matter 2080 01:15:36,200 --> 01:15:34,889 interacts with ordinary matter yeah we 2081 01:15:38,089 --> 01:15:36,210 actually had a discussion about dark 2082 01:15:39,620 --> 01:15:38,099 matter online during your talk okay 2083 01:15:41,540 --> 01:15:39,630 people wanting to know well what is dark 2084 01:15:53,200 --> 01:15:41,550 matter I said it if I knew that I'd be 2085 01:15:53,210 --> 01:16:04,680 yep 2086 01:16:09,669 --> 01:16:07,060 well I mean I could use another analogy 2087 01:16:11,260 --> 01:16:09,679 but to me the dark matter is traced 2088 01:16:13,750 --> 01:16:11,270 throughout the universe in these 2089 01:16:16,270 --> 01:16:13,760 filaments and then the thin layer of gas 2090 01:16:17,379 --> 01:16:16,280 and the leftover matter that the kind of 2091 01:16:19,240 --> 01:16:17,389 matter of mater kind of falls 2092 01:16:20,770 --> 01:16:19,250 gravitationally on top of that and where 2093 01:16:23,169 --> 01:16:20,780 it collapses together due to gravity it 2094 01:16:24,549 --> 01:16:23,179 starts forming stars so to me it's the 2095 01:16:25,720 --> 01:16:24,559 structure upon which everything else is 2096 01:16:27,100 --> 01:16:25,730 built when you see the large scale 2097 01:16:29,020 --> 01:16:27,110 structure in the universe it's defined 2098 01:16:30,459 --> 01:16:29,030 by dark matter the same way that the 2099 01:16:32,140 --> 01:16:30,469 scaffolding of a building defines the 2100 01:17:00,040 --> 01:16:32,150 structure of a building but I mean there 2101 01:17:01,709 --> 01:17:00,050 might be better analogies try and 2102 01:17:04,330 --> 01:17:01,719 summarize that question for the yeah so 2103 01:17:05,950 --> 01:17:04,340 for the online folks how confident we 2104 01:17:08,709 --> 01:17:05,960 are in the algorithms that allow us to 2105 01:17:10,299 --> 01:17:08,719 reduce the data basically so pretty 2106 01:17:11,740 --> 01:17:10,309 confident because we came at this a 2107 01:17:14,109 --> 01:17:11,750 couple different ways as I showed in the 2108 01:17:16,419 --> 01:17:14,119 talk we have comparison populations that 2109 01:17:18,040 --> 01:17:16,429 are very very well studied so we use 2110 01:17:19,510 --> 01:17:18,050 this camera there's a very very sense of 2111 01:17:21,399 --> 01:17:19,520 camera Hubble we measure the brightness 2112 01:17:23,649 --> 01:17:21,409 is in the colors of the stars and then 2113 01:17:25,060 --> 01:17:23,659 we use the same exact camryn filters to 2114 01:17:26,470 --> 01:17:25,070 measure a well-studied object and that's 2115 01:17:28,689 --> 01:17:26,480 our controls in this case I showed them 2116 01:17:30,640 --> 01:17:28,699 92 we've actually used it for loads of 2117 01:17:32,620 --> 01:17:30,650 Studies on Hubble but I'm going to do is 2118 01:17:34,209 --> 01:17:32,630 the best comparison here so you can do 2119 01:17:35,470 --> 01:17:34,219 an apples-to-apples comparison where a 2120 01:17:36,490 --> 01:17:35,480 lot of the systematics you might be 2121 01:17:37,660 --> 01:17:36,500 worried about just dropped by the 2122 01:17:39,609 --> 01:17:37,670 wayside because you're doing the same 2123 01:17:41,530 --> 01:17:39,619 exact thing with both our 92 and these 2124 01:17:42,729 --> 01:17:41,540 galaxies and then we also come at it 2125 01:17:45,189 --> 01:17:42,739 from a different angle we take the 2126 01:17:46,959 --> 01:17:45,199 theory of how stars evolved that pattern 2127 01:17:49,270 --> 01:17:46,969 they trace out in the diagram and we 2128 01:17:50,680 --> 01:17:49,280 calibrate those theoretical models to 2129 01:17:51,790 --> 01:17:50,690 the data that we've taken with this 2130 01:17:53,109 --> 01:17:51,800 camera over and over and over again so 2131 01:17:54,160 --> 01:17:53,119 that's another way of doing it so now 2132 01:17:55,810 --> 01:17:54,170 we're pretty confident and then 2133 01:17:58,030 --> 01:17:55,820 measuring the stars the signal noise for 2134 01:17:59,410 --> 01:17:58,040 to get this accuracy in the ages we got 2135 01:18:01,180 --> 01:17:59,420 two solenoids of 100 since you mentioned 2136 01:18:02,919 --> 01:18:01,190 signal noise so the signal noise ratio 2137 01:18:04,930 --> 01:18:02,929 is 100 so it's very very you know what 2138 01:18:07,109 --> 01:18:04,940 percent photometry and let me just say 2139 01:18:10,000 --> 01:18:07,119 the folks in this building are brilliant 2140 01:18:12,760 --> 01:18:10,010 I'm not an observer ok you guys are 2141 01:18:14,330 --> 01:18:12,770 absolutely brilliant at characterizing 2142 01:18:16,330 --> 01:18:14,340 all of the artifacts 2143 01:18:19,850 --> 01:18:16,340 could be possible in Hubble images okay 2144 01:18:21,440 --> 01:18:19,860 they have I mean they've had 25 years to 2145 01:18:23,630 --> 01:18:21,450 work at this and really understand all 2146 01:18:25,640 --> 01:18:23,640 the stuff and they do amazing stuff at 2147 01:18:28,070 --> 01:18:25,650 being able to really pull out what 2148 01:18:29,870 --> 01:18:28,080 signal and what's noise out of these out 2149 01:18:31,280 --> 01:18:29,880 of the datasets and a lot of the sources 2150 01:18:32,810 --> 01:18:31,290 of systematic error like for example 2151 01:18:35,330 --> 01:18:32,820 this object right here that I'm moving 2152 01:18:40,430 --> 01:18:35,340 to well I probably blew past it just now 2153 01:18:42,020 --> 01:18:40,440 but uh m92 m92 is a very crowded star 2154 01:18:44,540 --> 01:18:42,030 field so it gets a little noisier in the 2155 01:18:46,940 --> 01:18:44,550 data well I'll show you this these are 2156 01:18:48,800 --> 01:18:46,950 very this is a very sparse scar field so 2157 01:18:51,590 --> 01:18:48,810 it's pretty easy to measure the here me 2158 01:18:54,020 --> 01:18:51,600 show you again here that's a very sparse 2159 01:18:55,460 --> 01:18:54,030 image and if i zoom in on it here it's 2160 01:18:56,750 --> 01:18:55,470 pretty easy to measure the brightness of 2161 01:18:58,250 --> 01:18:56,760 this star the brightness of this star 2162 01:18:59,540 --> 01:18:58,260 and so forth because they're not 2163 01:19:00,980 --> 01:18:59,550 stepping on top of each other you know 2164 01:19:03,110 --> 01:19:00,990 it's just a nice way so well isolated 2165 01:19:04,430 --> 01:19:03,120 star so really this is we tried to make 2166 01:19:05,960 --> 01:19:04,440 this measurement a turkey shoot we did 2167 01:19:08,210 --> 01:19:05,970 very long exposures left the shutter 2168 01:19:09,440 --> 01:19:08,220 open for 16 orbits really get accurate 2169 01:19:10,790 --> 01:19:09,450 measurements of each of these stars and 2170 01:19:13,010 --> 01:19:10,800 there they're not crowding on top of 2171 01:19:14,450 --> 01:19:13,020 each other or anything so I'm like m92 2172 01:19:23,450 --> 01:19:14,460 it's a little harder because the stars 2173 01:19:25,070 --> 01:19:23,460 are crowding yeah gravity itself so self 2174 01:19:26,770 --> 01:19:25,080 gravity it's just it has a gravitational 2175 01:19:36,200 --> 01:19:26,780 influence on the rest of the dark matter 2176 01:19:40,850 --> 01:19:36,210 so it just collapses on itself Albert 2177 01:19:52,100 --> 01:19:40,860 Einstein to care all right any last 2178 01:19:54,050 --> 01:19:52,110 questions back corner up there I mean it 2179 01:19:56,090 --> 01:19:54,060 could happen if Elon Musk wants to you 2180 01:19:57,860 --> 01:19:56,100 know say must wants to say hey I want 2181 01:19:59,240 --> 01:19:57,870 you to launch a satellite on the SpaceX 2182 01:20:01,670 --> 01:19:59,250 for you guys or whatever you know it's 2183 01:20:02,660 --> 01:20:01,680 possible right now the discussions that 2184 01:20:04,160 --> 01:20:02,670 you know people are talking about 2185 01:20:05,270 --> 01:20:04,170 they're all talking about NASA launches 2186 01:20:06,470 --> 01:20:05,280 but you know it could happen in 2187 01:20:12,980 --> 01:20:06,480 partnership with private industry who 2188 01:20:14,000 --> 01:20:12,990 knows it's possible yeah so what which 2189 01:20:15,860 --> 01:20:14,010 many like to see the two newest 2190 01:20:21,470 --> 01:20:15,870 degeneracy videos or the deployment 2191 01:20:23,120 --> 01:20:21,480 video sure yeah there's a better one 2192 01:20:25,010 --> 01:20:23,130 available on the web now since I put 2193 01:20:26,900 --> 01:20:25,020 that one in the slide that is a little 2194 01:20:28,880 --> 01:20:26,910 more exciting this one is almost like 2195 01:20:30,050 --> 01:20:28,890 you know scale equals one time it almost 2196 01:20:34,820 --> 01:20:30,060 happens you have to it almost takes like 2197 01:20:36,260 --> 01:20:34,830 six months to watch it but uh we both is 2198 01:20:37,820 --> 01:20:36,270 this is why I don't put transitions in 2199 01:20:43,880 --> 01:20:37,830 my slides most of the time because I 2200 01:20:46,300 --> 01:20:43,890 hate waiting for those okay well well 2201 01:20:50,600 --> 01:20:46,310 while you play the video one more time 2202 01:20:52,550 --> 01:20:50,610 here's a question from online is it 2203 01:20:54,500 --> 01:20:52,560 possible that there could be planets 2204 01:20:56,270 --> 01:20:54,510 orbiting the stars in these small 2205 01:20:58,340 --> 01:20:56,280 galaxies these galaxies were formed 2206 01:21:01,400 --> 01:20:58,350 thirteen billion years ago they're low 2207 01:21:03,370 --> 01:21:01,410 metallicity the problem are you are we 2208 01:21:05,360 --> 01:21:03,380 going to find planets around them so 2209 01:21:08,150 --> 01:21:05,370 astronomers when they look for planets 2210 01:21:09,530 --> 01:21:08,160 around stars they you know planets are 2211 01:21:10,850 --> 01:21:09,540 very abundant and we're finding out that 2212 01:21:12,830 --> 01:21:10,860 they're that we find them around stars 2213 01:21:15,650 --> 01:21:12,840 all over the place on nearby stars but 2214 01:21:17,840 --> 01:21:15,660 the as Frank was just saying these stars 2215 01:21:19,760 --> 01:21:17,850 were born in clouds of gas that were 2216 01:21:22,160 --> 01:21:19,770 very pristine not a lot of material for 2217 01:21:23,510 --> 01:21:22,170 building planets so there's not a lot of 2218 01:21:25,520 --> 01:21:23,520 likelihood here that there would be 2219 01:21:27,590 --> 01:21:25,530 planets around the stars in these ultra 2220 01:21:29,920 --> 01:21:27,600 faint dwarf galaxies the analogy I can 2221 01:21:32,240 --> 01:21:29,930 make is that Hubble did a very very 2222 01:21:33,800 --> 01:21:32,250 thorough search for planets in a 2223 01:21:36,620 --> 01:21:33,810 globular cluster I guess it was around 2224 01:21:38,060 --> 01:21:36,630 15 years ago now 47 talk which is not 2225 01:21:39,950 --> 01:21:38,070 even as metal-poor as these ultra faint 2226 01:21:41,600 --> 01:21:39,960 dwarf galaxies it's a little bit it's a 2227 01:21:43,520 --> 01:21:41,610 little more metallicity than 10% solar 2228 01:21:45,290 --> 01:21:43,530 so it's not like 1% or a thousandth of 2229 01:21:47,230 --> 01:21:45,300 solar like these and they didn't find 2230 01:21:48,670 --> 01:21:47,240 any planets around 2231 01:21:50,200 --> 01:21:48,680 so really if you want to look for 2232 01:21:51,850 --> 01:21:50,210 planets you look for stars that are 2233 01:21:53,350 --> 01:21:51,860 closer and metallicity to the Sun 2234 01:21:55,150 --> 01:21:53,360 because those are more likely to be born 2235 01:21:56,440 --> 01:21:55,160 from material with a lot of enriched gas 2236 01:21:58,330 --> 01:21:56,450 and so forth around where you have the 2237 01:21:59,680 --> 01:21:58,340 building blocks of planets as well so 2238 01:22:01,240 --> 01:21:59,690 there's probably not a lot of planets in 2239 01:22:04,000 --> 01:22:01,250 these galaxies and these ultra faint 2240 01:22:05,740 --> 01:22:04,010 door galaxies okay well thank you all 2241 01:22:08,380 --> 01:22:05,750 for coming tonight if you have any last 2242 01:22:11,320 --> 01:22:08,390 questions come up and see if we can chat 2243 01:22:14,040 --> 01:22:11,330 next month um bill Blair will be talking 2244 01:22:16,480 --> 01:22:14,050 about Stella populations in Messier III 2245 01:22:18,190 --> 01:22:16,490 remember that next month you must 2246 01:22:21,310 --> 01:22:18,200 approach from the south not from the 2247 01:22:28,130 --> 01:22:21,320 north and let us give Tom another warm 2248 01:22:45,560 --> 01:22:43,220 I went when I got out of graduate school