1 00:00:05,269 --> 00:00:03,830 welcome to the space telescope public 2 00:00:08,150 --> 00:00:05,279 lecture series 3 00:00:09,030 --> 00:00:08,160 tonight's talk the darkest secrets of 4 00:00:14,150 --> 00:00:09,040 the universe 5 00:00:18,230 --> 00:00:16,150 this i'm dr frank summers of the space 6 00:00:20,950 --> 00:00:18,240 telescope science institute 7 00:00:21,670 --> 00:00:20,960 and um as we have so told you in past 8 00:00:23,670 --> 00:00:21,680 months the 9 00:00:25,189 --> 00:00:23,680 space telescope public ledger series 10 00:00:27,830 --> 00:00:25,199 will be online only 11 00:00:29,669 --> 00:00:27,840 until further notice thanks to our 12 00:00:30,950 --> 00:00:29,679 amazing tech team that helps us get it 13 00:00:34,549 --> 00:00:30,960 out there online 14 00:00:37,990 --> 00:00:34,559 thomas marufu and grant justice 15 00:00:41,110 --> 00:00:38,000 our upcoming talks include in february 16 00:00:42,869 --> 00:00:41,120 the milky way versus andromeda when 17 00:00:45,910 --> 00:00:42,879 galaxies collide 18 00:00:47,830 --> 00:00:45,920 it's a titanic battle for supremacy in 19 00:00:51,029 --> 00:00:47,840 the local group of galaxies 20 00:00:53,510 --> 00:00:51,039 who will win tune in next 21 00:00:55,990 --> 00:00:53,520 month uh laura pritchard will discuss 22 00:00:59,830 --> 00:00:56,000 that and reveal the answers 23 00:01:01,830 --> 00:00:59,840 in march uh tom brown head of the hubble 24 00:01:04,789 --> 00:01:01,840 mission office here at space telescope 25 00:01:06,630 --> 00:01:04,799 will give a wonderful overview talk 26 00:01:09,510 --> 00:01:06,640 called the hubble space telescope 27 00:01:11,109 --> 00:01:09,520 from cosmological conflict to alien 28 00:01:14,149 --> 00:01:11,119 atmospheres 29 00:01:16,310 --> 00:01:14,159 and in april we have a special guest 30 00:01:17,270 --> 00:01:16,320 author christopher wanzek will come and 31 00:01:19,990 --> 00:01:17,280 talk to us about 32 00:01:20,870 --> 00:01:20,000 space farers how humans will settle the 33 00:01:24,310 --> 00:01:20,880 moon 34 00:01:26,469 --> 00:01:24,320 mars and beyond we have talks scheduled 35 00:01:28,149 --> 00:01:26,479 throughout the year and if you want to 36 00:01:30,710 --> 00:01:28,159 find out about them 37 00:01:31,710 --> 00:01:30,720 you can go to our website if you just 38 00:01:34,469 --> 00:01:31,720 type in 39 00:01:37,749 --> 00:01:34,479 sdsci.edu public hyphen 40 00:01:39,830 --> 00:01:37,759 lectures you'll find this webpage 41 00:01:41,670 --> 00:01:39,840 and in the lower left you can see the 42 00:01:44,069 --> 00:01:41,680 links to our webcasts 43 00:01:44,789 --> 00:01:44,079 both on the space telescope webcasting 44 00:01:48,069 --> 00:01:44,799 page 45 00:01:50,230 --> 00:01:48,079 and our youtube playlist if you would 46 00:01:52,069 --> 00:01:50,240 like to be reminded monthly about it 47 00:01:54,149 --> 00:01:52,079 in the lower right you can see how to 48 00:01:57,510 --> 00:01:54,159 subscribe to 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00:02:35,840 um that when if you subscribe you'll get 65 00:02:39,990 --> 00:02:36,959 new video notices 66 00:02:42,150 --> 00:02:40,000 and reminders of live events 67 00:02:43,509 --> 00:02:42,160 if you have comments or questions you 68 00:02:47,150 --> 00:02:43,519 can send them to us 69 00:02:49,750 --> 00:02:47,160 via the email address public lecture 70 00:02:52,229 --> 00:02:49,760 stsci.edu 71 00:02:52,869 --> 00:02:52,239 if you want other information about 72 00:02:54,949 --> 00:02:52,879 hubble 73 00:02:56,949 --> 00:02:54,959 or the james webb space telescope or the 74 00:03:00,229 --> 00:02:56,959 space telescope science institute 75 00:03:02,309 --> 00:03:00,239 you can follow us on facebook on twitter 76 00:03:04,309 --> 00:03:02,319 uh our youtube channels both for hubble 77 00:03:07,910 --> 00:03:04,319 and for and for web um 78 00:03:09,110 --> 00:03:07,920 and on instagram myself i do a tiny bit 79 00:03:11,670 --> 00:03:09,120 of social media 80 00:03:13,509 --> 00:03:11,680 on facebook and on twitter if you want 81 00:03:15,750 --> 00:03:13,519 to hear what's up with me 82 00:03:18,149 --> 00:03:15,760 but what's usually up with me is this 83 00:03:20,830 --> 00:03:18,159 part of the program where i give you 84 00:03:23,110 --> 00:03:20,840 the news from the universe for january 85 00:03:26,149 --> 00:03:23,120 2021 86 00:03:29,110 --> 00:03:26,159 and our first story tonight the 87 00:03:29,430 --> 00:03:29,120 darkest sky you ever thought about you 88 00:03:31,270 --> 00:03:29,440 know 89 00:03:33,589 --> 00:03:31,280 getting out if you want to see the stars 90 00:03:36,710 --> 00:03:33,599 you've got to get out to a dark sky 91 00:03:38,390 --> 00:03:36,720 well i was in new york city and worked 92 00:03:39,910 --> 00:03:38,400 at the hayden planetarium the american 93 00:03:42,789 --> 00:03:39,920 museum of natural history 94 00:03:44,550 --> 00:03:42,799 and we used to do stargazing parties in 95 00:03:47,670 --> 00:03:44,560 central park 96 00:03:49,509 --> 00:03:47,680 this image here is uh from urban scopes 97 00:03:52,309 --> 00:03:49,519 and you can see they're actually using 98 00:03:54,470 --> 00:03:52,319 telescopes in new york city 99 00:03:56,070 --> 00:03:54,480 uh which you generally don't recommend 100 00:03:58,070 --> 00:03:56,080 because of all the light pollution with 101 00:03:59,910 --> 00:03:58,080 all those bright lights of the city 102 00:04:01,270 --> 00:03:59,920 you really can't see many stars matter 103 00:04:03,509 --> 00:04:01,280 of fact in this picture there are 104 00:04:05,030 --> 00:04:03,519 zero stars in the background although i 105 00:04:05,830 --> 00:04:05,040 will tell you that having done it in 106 00:04:07,990 --> 00:04:05,840 central park 107 00:04:09,910 --> 00:04:08,000 you can see a smattering of stars and 108 00:04:12,630 --> 00:04:09,920 sun and and the planets 109 00:04:15,110 --> 00:04:12,640 and the moon for that but if you really 110 00:04:17,189 --> 00:04:15,120 want to get a dark sky 111 00:04:19,430 --> 00:04:17,199 i would suggest going to a national park 112 00:04:21,349 --> 00:04:19,440 like yosemite okay 113 00:04:22,469 --> 00:04:21,359 when my family took a vacation to 114 00:04:25,830 --> 00:04:22,479 yosemite 115 00:04:27,590 --> 00:04:25,840 oh gosh it's coming out 15 years ago 116 00:04:29,110 --> 00:04:27,600 i took my son out into the middle of 117 00:04:31,909 --> 00:04:29,120 yosemite valley and we 118 00:04:33,830 --> 00:04:31,919 looked up and we saw one of the darkest 119 00:04:35,990 --> 00:04:33,840 guys we'd ever seen 120 00:04:37,670 --> 00:04:36,000 we saw so many stars that i as a 121 00:04:39,270 --> 00:04:37,680 professional astronomer 122 00:04:41,110 --> 00:04:39,280 couldn't make sense of them because 123 00:04:43,749 --> 00:04:41,120 there were too many of them 124 00:04:45,350 --> 00:04:43,759 there were so many stars so getting out 125 00:04:47,590 --> 00:04:45,360 to like national parks will give you a 126 00:04:51,030 --> 00:04:47,600 really good dark sky 127 00:04:51,590 --> 00:04:51,040 but even the darkest sky on earth isn't 128 00:04:54,790 --> 00:04:51,600 really 129 00:04:55,590 --> 00:04:54,800 fully dark and one of the reasons is 130 00:04:58,230 --> 00:04:55,600 because 131 00:05:00,230 --> 00:04:58,240 of something called the zodiacal light 132 00:05:04,070 --> 00:05:00,240 now this is shown in this diagram 133 00:05:06,310 --> 00:05:04,080 here okay so this band on the right here 134 00:05:07,909 --> 00:05:06,320 this is the milky way this is the band 135 00:05:09,029 --> 00:05:07,919 of the milky way that goes across the 136 00:05:11,350 --> 00:05:09,039 sky 137 00:05:13,350 --> 00:05:11,360 but this other band this bright light 138 00:05:16,629 --> 00:05:13,360 over here on the left 139 00:05:17,350 --> 00:05:16,639 that is the zodiacal light now what this 140 00:05:20,230 --> 00:05:17,360 really is 141 00:05:20,790 --> 00:05:20,240 is dust in the plane of our solar system 142 00:05:22,469 --> 00:05:20,800 okay 143 00:05:24,950 --> 00:05:22,479 the planets are all in a plane and 144 00:05:26,790 --> 00:05:24,960 there's bits of dust within that plane 145 00:05:28,629 --> 00:05:26,800 that scatter some of the light from the 146 00:05:31,830 --> 00:05:28,639 sun so 147 00:05:34,230 --> 00:05:31,840 we on earth being embedded in 148 00:05:35,110 --> 00:05:34,240 that milky way in that solar system 149 00:05:36,870 --> 00:05:35,120 plane 150 00:05:38,950 --> 00:05:36,880 are always going to be looking a little 151 00:05:42,230 --> 00:05:38,960 bit through that zodiacal 152 00:05:45,110 --> 00:05:42,240 dust so our dark knights 153 00:05:46,710 --> 00:05:45,120 aren't as dark as they really could be 154 00:05:47,430 --> 00:05:46,720 how are we going to find out how dark 155 00:05:51,110 --> 00:05:47,440 the nice guy 156 00:05:53,510 --> 00:05:51,120 really really really really is well 157 00:05:54,629 --> 00:05:53,520 we need to get outside the solar system 158 00:05:56,710 --> 00:05:54,639 fortunately 159 00:05:59,029 --> 00:05:56,720 we happen to have a space mission that 160 00:06:01,430 --> 00:05:59,039 has got has done just that 161 00:06:03,909 --> 00:06:01,440 this is an artist's depiction of the new 162 00:06:05,909 --> 00:06:03,919 horizons spacecraft craft 163 00:06:07,670 --> 00:06:05,919 and if you remember new horizons went 164 00:06:10,390 --> 00:06:07,680 out and visited the pluto 165 00:06:12,870 --> 00:06:10,400 karen system and it also went past a 166 00:06:16,070 --> 00:06:12,880 kuiper belt object called erikoff 167 00:06:16,950 --> 00:06:16,080 and uh it's now out you know 40 50 a.u 168 00:06:21,749 --> 00:06:16,960 outside 169 00:06:24,390 --> 00:06:21,759 almost all of that sodium dust 170 00:06:26,790 --> 00:06:24,400 so what the what the experiment they did 171 00:06:29,430 --> 00:06:26,800 was using new horizons 172 00:06:30,230 --> 00:06:29,440 to measure the darkness of the night sky 173 00:06:33,350 --> 00:06:30,240 the true 174 00:06:36,469 --> 00:06:33,360 darkness of the night sky and what they 175 00:06:38,950 --> 00:06:36,479 found is that when you measure 176 00:06:40,070 --> 00:06:38,960 the deepest darkest black that new 177 00:06:43,670 --> 00:06:40,080 horizons 178 00:06:46,629 --> 00:06:43,680 gets out there um and you consider 179 00:06:48,390 --> 00:06:46,639 what hubble has seen like if you take 180 00:06:49,270 --> 00:06:48,400 all the galaxies this is an image of the 181 00:06:51,350 --> 00:06:49,280 ultra deep field 182 00:06:52,309 --> 00:06:51,360 you take all the the light that that 183 00:06:54,309 --> 00:06:52,319 hubble has seen 184 00:06:56,070 --> 00:06:54,319 and you add them up and then you look 185 00:06:58,710 --> 00:06:56,080 for you say what's missing 186 00:06:59,510 --> 00:06:58,720 okay um the brightness of the night sky 187 00:07:01,110 --> 00:06:59,520 the absolute 188 00:07:02,870 --> 00:07:01,120 final brightness of the night sky the 189 00:07:06,150 --> 00:07:02,880 what we call the optical sky 190 00:07:09,189 --> 00:07:06,160 background is about twice as bright 191 00:07:11,990 --> 00:07:09,199 as all the stuff that hubble sees so 192 00:07:14,550 --> 00:07:12,000 the idea being that there are unresolved 193 00:07:17,830 --> 00:07:14,560 galaxies galaxies that hubble can't see 194 00:07:19,589 --> 00:07:17,840 too small too faint just too spread out 195 00:07:21,909 --> 00:07:19,599 that hubble can't see them 196 00:07:23,029 --> 00:07:21,919 and the light the combined light from 197 00:07:25,430 --> 00:07:23,039 all those 198 00:07:27,189 --> 00:07:25,440 is about equal to the light from all the 199 00:07:29,830 --> 00:07:27,199 stuff that it can see 200 00:07:30,550 --> 00:07:29,840 so maybe like half of the galaxies out 201 00:07:32,870 --> 00:07:30,560 in the universe 202 00:07:34,870 --> 00:07:32,880 are stuff hubble can't see and that 203 00:07:36,469 --> 00:07:34,880 actually contrasts against a previous 204 00:07:38,790 --> 00:07:36,479 estimate that was done with simulations 205 00:07:41,990 --> 00:07:38,800 that said oh no no hubble only sees 10 206 00:07:43,589 --> 00:07:42,000 of the light in the universe actually um 207 00:07:45,909 --> 00:07:43,599 what the new horizons measurement seems 208 00:07:48,550 --> 00:07:45,919 to be that hubble sees about 50 209 00:07:49,830 --> 00:07:48,560 of the light in the universe so with new 210 00:07:52,629 --> 00:07:49,840 horizons being 211 00:07:53,350 --> 00:07:52,639 outside of the main part of the solar 212 00:07:55,350 --> 00:07:53,360 system 213 00:07:56,950 --> 00:07:55,360 we're actually able to able to level the 214 00:08:00,309 --> 00:07:56,960 true black level 215 00:08:04,150 --> 00:08:02,469 our second story for you tonight is 216 00:08:07,589 --> 00:08:04,160 called the fading glory 217 00:08:10,150 --> 00:08:07,599 of the stingray nebula now this 218 00:08:10,869 --> 00:08:10,160 is the stingray nebula and it sort of 219 00:08:12,869 --> 00:08:10,879 gets this 220 00:08:14,950 --> 00:08:12,879 uh it sort of kind of looks like a 221 00:08:16,950 --> 00:08:14,960 stingray um but it has nothing to do 222 00:08:19,990 --> 00:08:16,960 with actual an actual stingray 223 00:08:21,830 --> 00:08:20,000 it is a planetary nebula which also 224 00:08:24,869 --> 00:08:21,840 actually has nothing to do with planets 225 00:08:26,950 --> 00:08:24,879 all right so planetary nebula were a 226 00:08:28,230 --> 00:08:26,960 category created by people who said hey 227 00:08:28,869 --> 00:08:28,240 they look round they look sort of like 228 00:08:30,950 --> 00:08:28,879 planets 229 00:08:32,230 --> 00:08:30,960 we'll call them a planetary nebula they 230 00:08:34,709 --> 00:08:32,240 have nothing to do with planets it's 231 00:08:37,829 --> 00:08:34,719 actually a dying star 232 00:08:41,350 --> 00:08:37,839 this star here in the center 233 00:08:43,829 --> 00:08:41,360 is a star at the end of its life and 234 00:08:45,269 --> 00:08:43,839 it's blowing off its outer layers okay 235 00:08:46,310 --> 00:08:45,279 it's gone through its hydrogen and 236 00:08:48,870 --> 00:08:46,320 helium fusion 237 00:08:49,509 --> 00:08:48,880 um and it's blowing off its outer layers 238 00:08:51,990 --> 00:08:49,519 this 239 00:08:52,870 --> 00:08:52,000 gas that you see around it is gas that 240 00:08:55,590 --> 00:08:52,880 have been 241 00:08:56,630 --> 00:08:55,600 ejected from the star during its death 242 00:08:58,150 --> 00:08:56,640 and that star 243 00:09:00,630 --> 00:08:58,160 is really really bright and really 244 00:09:03,829 --> 00:09:00,640 really hot and is illuminating 245 00:09:05,670 --> 00:09:03,839 and ionizing the gases around it but 246 00:09:08,070 --> 00:09:05,680 this is the way the stingray nebula 247 00:09:09,990 --> 00:09:08,080 looked in 1996 248 00:09:11,750 --> 00:09:10,000 and hubble has taken more than one image 249 00:09:14,790 --> 00:09:11,760 of the stingray nebula 250 00:09:19,190 --> 00:09:14,800 and by the time it got to 2016 251 00:09:26,949 --> 00:09:22,630 yeah that's interesting it went from 252 00:09:29,829 --> 00:09:26,959 really bright in in 1996 to really dim 253 00:09:31,670 --> 00:09:29,839 in 2016 much dimmer matter of fact 254 00:09:33,590 --> 00:09:31,680 here's an animated gif of it 255 00:09:35,430 --> 00:09:33,600 and you can see the stingray nebula 256 00:09:38,550 --> 00:09:35,440 slowly fading 257 00:09:41,590 --> 00:09:38,560 over 20 years what's 258 00:09:44,870 --> 00:09:41,600 going on here i mean we just don't 259 00:09:48,310 --> 00:09:44,880 see things like this fade that quickly 260 00:09:49,030 --> 00:09:48,320 all right so here's uh the 1996 on the 261 00:09:52,389 --> 00:09:49,040 left 262 00:09:54,630 --> 00:09:52,399 2016 on the right so this is 263 00:09:56,310 --> 00:09:54,640 this is really kind of an unprecedented 264 00:09:59,190 --> 00:09:56,320 change in the light admitted 265 00:10:00,470 --> 00:09:59,200 and this is hot nitrogen hydrogen and 266 00:10:02,949 --> 00:10:00,480 oxygen emission 267 00:10:04,550 --> 00:10:02,959 and these lines are ionized by that 268 00:10:07,590 --> 00:10:04,560 central star 269 00:10:10,470 --> 00:10:07,600 so in particular the oxygen emission 270 00:10:13,269 --> 00:10:10,480 has dropped by a factor of a thousand 271 00:10:16,310 --> 00:10:13,279 over the course of 20 years 272 00:10:21,910 --> 00:10:16,320 this means that the central star 273 00:10:25,590 --> 00:10:21,920 which has a phone number of sao244567 274 00:10:27,590 --> 00:10:25,600 is decreasing its ionizing output 275 00:10:30,389 --> 00:10:27,600 the gases are still there they're just 276 00:10:33,269 --> 00:10:30,399 not being ionized by that central star 277 00:10:33,910 --> 00:10:33,279 so they aren't glowing as much and the 278 00:10:36,389 --> 00:10:33,920 idea 279 00:10:38,470 --> 00:10:36,399 is that the central star was really 280 00:10:41,829 --> 00:10:38,480 bright in in 1996 281 00:10:42,150 --> 00:10:41,839 but it has expanded and when you expand 282 00:10:47,350 --> 00:10:42,160 you 283 00:10:49,509 --> 00:10:47,360 ionizing radiation 284 00:10:52,310 --> 00:10:49,519 right matter of fact observations from 285 00:10:54,230 --> 00:10:52,320 1971 to 2002 286 00:10:56,389 --> 00:10:54,240 showed that the temperature of this star 287 00:10:59,430 --> 00:10:56,399 actually increased by a factor of 288 00:11:00,310 --> 00:10:59,440 two and a half during that time so over 289 00:11:02,150 --> 00:11:00,320 30 years 290 00:11:03,350 --> 00:11:02,160 its temperature increased by a factor of 291 00:11:06,550 --> 00:11:03,360 two and a half 292 00:11:08,550 --> 00:11:06,560 and now it appears to be cooling again 293 00:11:09,670 --> 00:11:08,560 uh one of the research main researchers 294 00:11:12,710 --> 00:11:09,680 on this surmised 295 00:11:13,750 --> 00:11:12,720 that perhaps there was a brief flash of 296 00:11:18,069 --> 00:11:13,760 helium 297 00:11:20,389 --> 00:11:18,079 around the core of the star 298 00:11:21,110 --> 00:11:20,399 so the idea would be that that the star 299 00:11:23,750 --> 00:11:21,120 collapsed 300 00:11:25,430 --> 00:11:23,760 in ignited a little bit of helium helium 301 00:11:28,470 --> 00:11:25,440 fusion around the core 302 00:11:30,949 --> 00:11:28,480 that a helium fusion caused it to 303 00:11:33,190 --> 00:11:30,959 to brighten and get hot high temperature 304 00:11:36,470 --> 00:11:33,200 it made a lot of ionizing radiation 305 00:11:37,590 --> 00:11:36,480 but it also caused it to expand and then 306 00:11:40,069 --> 00:11:37,600 cool 307 00:11:42,069 --> 00:11:40,079 and the really crazy thing about this as 308 00:11:45,350 --> 00:11:42,079 this is all happened on a time scale 309 00:11:47,670 --> 00:11:45,360 of about 50 years i mean when when we 310 00:11:50,629 --> 00:11:47,680 think of astronomy we don't think of 311 00:11:52,710 --> 00:11:50,639 you know nebulae like this ex changing 312 00:11:55,670 --> 00:11:52,720 over the time scale of 50 years 313 00:11:55,990 --> 00:11:55,680 this is a very brief event and it's 314 00:11:58,150 --> 00:11:56,000 really 315 00:11:59,030 --> 00:11:58,160 cool we'll be studying it and we'll be 316 00:12:01,030 --> 00:11:59,040 watching it 317 00:12:02,550 --> 00:12:01,040 because if it continues to fade at the 318 00:12:05,190 --> 00:12:02,560 way it is matter of fact 319 00:12:06,150 --> 00:12:05,200 the stingray nebula will barely be 320 00:12:09,110 --> 00:12:06,160 detectable 321 00:12:10,230 --> 00:12:09,120 in another couple of decades so stay 322 00:12:15,829 --> 00:12:10,240 tuned to see how 323 00:12:22,550 --> 00:12:19,030 and now we go to our speaker tonight 324 00:12:23,910 --> 00:12:22,560 um our speaker tonight um is raja gujata 325 00:12:27,190 --> 00:12:23,920 kurta 326 00:12:29,990 --> 00:12:27,200 and he is the a professor 327 00:12:31,030 --> 00:12:30,000 and the department chair and astronomy 328 00:12:33,190 --> 00:12:31,040 and after physics 329 00:12:34,790 --> 00:12:33,200 at the university of california santa 330 00:12:36,629 --> 00:12:34,800 cruz 331 00:12:38,389 --> 00:12:36,639 i'm told that i'm only allowed to say 332 00:12:38,949 --> 00:12:38,399 condolences on him being department 333 00:12:42,150 --> 00:12:38,959 chair 334 00:12:42,550 --> 00:12:42,160 because that is actually quite true you 335 00:12:44,069 --> 00:12:42,560 end up 336 00:12:45,910 --> 00:12:44,079 having to do an awful lot of work as 337 00:12:48,230 --> 00:12:45,920 department chair and it interrupts the 338 00:12:50,230 --> 00:12:48,240 flow of your research and raja has been 339 00:12:53,110 --> 00:12:50,240 an amazing researcher 340 00:12:54,310 --> 00:12:53,120 ah gosh we first met in the early 90s at 341 00:12:56,230 --> 00:12:54,320 princeton 342 00:12:58,230 --> 00:12:56,240 um uh when we went there and he was 343 00:13:00,870 --> 00:12:58,240 doing some marvelous stuff there 344 00:13:01,590 --> 00:13:00,880 he's worked on all sorts of things a lot 345 00:13:03,910 --> 00:13:01,600 most of them 346 00:13:05,030 --> 00:13:03,920 are concerning galaxies uh he's worked 347 00:13:07,750 --> 00:13:05,040 on various large 348 00:13:09,990 --> 00:13:07,760 surveys he's worked on especially the 349 00:13:12,870 --> 00:13:10,000 andromeda galaxy doing surveys of 350 00:13:13,430 --> 00:13:12,880 looking deep into the andromeda galaxies 351 00:13:17,350 --> 00:13:13,440 um 352 00:13:19,190 --> 00:13:17,360 know one of the people that i always 353 00:13:19,990 --> 00:13:19,200 listen to at conferences because i know 354 00:13:21,670 --> 00:13:20,000 that when he does 355 00:13:23,990 --> 00:13:21,680 it he's going to do it right and he's 356 00:13:26,069 --> 00:13:24,000 going to explain it well 357 00:13:27,350 --> 00:13:26,079 he's received numerous awards including 358 00:13:30,790 --> 00:13:27,360 a hubble fellowship 359 00:13:34,470 --> 00:13:30,800 an alfred sloan research fellowship um 360 00:13:39,350 --> 00:13:34,480 and the beverly sackler lecturer 361 00:13:40,870 --> 00:13:39,360 award um and so raja's been you know 362 00:13:42,470 --> 00:13:40,880 somebody that i've looked to for you 363 00:13:45,189 --> 00:13:42,480 know for well it's almost 364 00:13:46,710 --> 00:13:45,199 for 30 years now uh he got i didn't 365 00:13:47,990 --> 00:13:46,720 mention where he got his degrees he got 366 00:13:50,949 --> 00:13:48,000 his bachelor's uh 367 00:13:52,389 --> 00:13:50,959 from xavier's college in kolkata in 368 00:13:54,629 --> 00:13:52,399 india 369 00:13:56,069 --> 00:13:54,639 and he got his phd at princeton 370 00:13:58,949 --> 00:13:56,079 university 371 00:13:59,750 --> 00:13:58,959 uh one thing to tell about him is that 372 00:14:03,509 --> 00:13:59,760 actually 373 00:14:05,269 --> 00:14:03,519 despite all the success um astronomy was 374 00:14:08,150 --> 00:14:05,279 his plan b 375 00:14:09,350 --> 00:14:08,160 when raja wanted to was thinking about 376 00:14:10,069 --> 00:14:09,360 what he was going to be in life he 377 00:14:12,870 --> 00:14:10,079 wanted to be an 378 00:14:14,550 --> 00:14:12,880 artist i understand he is a quite an 379 00:14:16,550 --> 00:14:14,560 accomplished painter 380 00:14:17,670 --> 00:14:16,560 and he can tell you more about that but 381 00:14:24,949 --> 00:14:17,680 ladies and gentlemen 382 00:14:28,230 --> 00:14:27,030 thank you so much frank for that kind 383 00:14:31,990 --> 00:14:28,240 introduction 384 00:14:33,990 --> 00:14:32,000 uh it's a real pleasure to be 385 00:14:36,150 --> 00:14:34,000 giving this public lecture this is going 386 00:14:38,470 --> 00:14:36,160 to be my largest 387 00:14:40,550 --> 00:14:38,480 in terms of audience largest public 388 00:14:45,269 --> 00:14:40,560 lecture it's an online lecture 389 00:14:47,990 --> 00:14:45,279 and i'm really privileged to be 390 00:14:49,829 --> 00:14:48,000 a speaker in this series the space 391 00:14:50,230 --> 00:14:49,839 telescope science institute feels like 392 00:14:52,550 --> 00:14:50,240 home 393 00:14:54,310 --> 00:14:52,560 i was an employee of the space telescope 394 00:14:58,470 --> 00:14:54,320 science institute 395 00:15:01,750 --> 00:14:58,480 it was 20 27 years ago 396 00:15:03,590 --> 00:15:01,760 and um also i was happy to see that the 397 00:15:05,030 --> 00:15:03,600 following speakers in the series laura 398 00:15:06,710 --> 00:15:05,040 pritchard was my 399 00:15:08,150 --> 00:15:06,720 student when she was an undergraduate 400 00:15:09,269 --> 00:15:08,160 and a master's student she did her 401 00:15:10,870 --> 00:15:09,279 research with me 402 00:15:12,310 --> 00:15:10,880 and tom brown has been a longtime 403 00:15:14,949 --> 00:15:12,320 collaborator 404 00:15:15,750 --> 00:15:14,959 so i'm going to speak about the darkest 405 00:15:19,189 --> 00:15:15,760 secrets 406 00:15:20,710 --> 00:15:19,199 of the universe i in addition to being 407 00:15:23,910 --> 00:15:20,720 at santa cruz for 408 00:15:26,310 --> 00:15:23,920 now coming up on uh 27 years 409 00:15:28,470 --> 00:15:26,320 i was five years ago i was visiting 410 00:15:29,990 --> 00:15:28,480 faculty at google's headquarters in 411 00:15:32,949 --> 00:15:30,000 mountain view where they've 412 00:15:34,550 --> 00:15:32,959 really helped me with my educational 413 00:15:37,350 --> 00:15:34,560 projects you know bringing 414 00:15:38,629 --> 00:15:37,360 stem research to high school students i 415 00:15:40,230 --> 00:15:38,639 won't say much about that 416 00:15:41,749 --> 00:15:40,240 in my talk but if you're interested 417 00:15:45,269 --> 00:15:41,759 please ask questions 418 00:15:48,870 --> 00:15:45,279 all right so i'm going to 419 00:15:51,990 --> 00:15:48,880 plunge right in and focus on certain 420 00:15:53,910 --> 00:15:52,000 aspects of the of the universe 421 00:15:55,670 --> 00:15:53,920 certain dark secrets there are many dark 422 00:15:59,829 --> 00:15:55,680 secrets i'll focus on 423 00:16:02,550 --> 00:15:59,839 a few of them in particular i want to 424 00:16:05,509 --> 00:16:02,560 talk about galaxies because they are 425 00:16:08,069 --> 00:16:05,519 basic building blocks of the cosmos 426 00:16:09,189 --> 00:16:08,079 in the same way that atoms are basic 427 00:16:13,189 --> 00:16:09,199 building blocks 428 00:16:17,430 --> 00:16:16,629 what atoms are to matter galaxies are to 429 00:16:20,629 --> 00:16:17,440 the universe 430 00:16:22,389 --> 00:16:20,639 and here's what i mean by this atoms are 431 00:16:23,269 --> 00:16:22,399 not the smallest building blocks of 432 00:16:26,069 --> 00:16:23,279 matter 433 00:16:27,030 --> 00:16:26,079 clearly atoms can be broken up into 434 00:16:31,110 --> 00:16:27,040 smaller 435 00:16:33,350 --> 00:16:31,120 into 436 00:16:36,790 --> 00:16:33,360 protons neutrons electrons protons and 437 00:16:38,470 --> 00:16:36,800 neutrons can be broken up further 438 00:16:39,990 --> 00:16:38,480 and you know of course you can have 439 00:16:41,430 --> 00:16:40,000 larger building blocks than atoms you 440 00:16:43,030 --> 00:16:41,440 can have molecules which is something 441 00:16:44,710 --> 00:16:43,040 we'll talk about in a minute you can 442 00:16:45,749 --> 00:16:44,720 have you know brick and mortar you can 443 00:16:48,389 --> 00:16:45,759 have 444 00:16:49,590 --> 00:16:48,399 concrete bars that you know metal rods 445 00:16:52,230 --> 00:16:49,600 that make up buildings 446 00:16:54,629 --> 00:16:52,240 in the same way galaxies are not the 447 00:16:56,310 --> 00:16:54,639 smallest nor the 448 00:16:57,829 --> 00:16:56,320 largest building blocks of the cosmos 449 00:16:59,030 --> 00:16:57,839 you know clearly stars and planets are 450 00:17:01,509 --> 00:16:59,040 smaller building blocks 451 00:17:03,189 --> 00:17:01,519 and clusters of galaxies and super 452 00:17:06,150 --> 00:17:03,199 clusters are bigger structures 453 00:17:07,510 --> 00:17:06,160 however atoms are super important to 454 00:17:10,630 --> 00:17:07,520 matter because 455 00:17:12,150 --> 00:17:10,640 our understanding of atoms led to some 456 00:17:15,110 --> 00:17:12,160 of the biggest revolutions 457 00:17:17,590 --> 00:17:15,120 in physics understanding the you know 458 00:17:20,710 --> 00:17:17,600 understanding sort of the 459 00:17:22,870 --> 00:17:20,720 very fabric of matter itself 460 00:17:24,309 --> 00:17:22,880 made huge progress human beings made 461 00:17:25,510 --> 00:17:24,319 huge progress in our understanding of 462 00:17:28,150 --> 00:17:25,520 matter itself 463 00:17:30,150 --> 00:17:28,160 when we understood the nature of atoms 464 00:17:31,750 --> 00:17:30,160 this was the birth of quantum mechanics 465 00:17:33,350 --> 00:17:31,760 in the same way i will argue that 466 00:17:34,549 --> 00:17:33,360 galaxies are really important even 467 00:17:35,510 --> 00:17:34,559 though they are not the biggest nor 468 00:17:37,510 --> 00:17:35,520 smallest 469 00:17:39,190 --> 00:17:37,520 they're the most important because if it 470 00:17:42,549 --> 00:17:39,200 weren't for the fact that 471 00:17:45,990 --> 00:17:42,559 you and i and frank and thomas 472 00:17:49,590 --> 00:17:46,000 and grant the fact that we are live in 473 00:17:51,190 --> 00:17:49,600 a galaxy makes us who we are 474 00:17:53,270 --> 00:17:51,200 the fact that we live not just in a 475 00:17:56,230 --> 00:17:53,280 galaxy we live in a large 476 00:17:57,190 --> 00:17:56,240 dark matter dominated galaxy is really 477 00:17:59,510 --> 00:17:57,200 what 478 00:18:00,710 --> 00:17:59,520 makes complex life here on earth 479 00:18:02,310 --> 00:18:00,720 possible 480 00:18:05,430 --> 00:18:02,320 let me illustrate this with my next 481 00:18:05,830 --> 00:18:05,440 slide i like to open with a picture of 482 00:18:08,310 --> 00:18:05,840 my 483 00:18:10,390 --> 00:18:08,320 son lounging on the carpet you know 484 00:18:13,590 --> 00:18:10,400 there he is 485 00:18:16,390 --> 00:18:13,600 i didn't promise he'd be human 486 00:18:17,669 --> 00:18:16,400 so there's an example of canine life and 487 00:18:19,990 --> 00:18:17,679 let me show you two other 488 00:18:21,750 --> 00:18:20,000 examples of life there's a particular 489 00:18:23,669 --> 00:18:21,760 form of life that's been 490 00:18:25,190 --> 00:18:23,679 really capturing our attention more than 491 00:18:27,430 --> 00:18:25,200 just our attention of late 492 00:18:29,270 --> 00:18:27,440 and that's the coronavirus and there's a 493 00:18:31,350 --> 00:18:29,280 picture of a human being 494 00:18:33,350 --> 00:18:31,360 so three forms of life right there in 495 00:18:34,310 --> 00:18:33,360 one picture you have two in the inset 496 00:18:36,870 --> 00:18:34,320 one in the main 497 00:18:39,510 --> 00:18:36,880 picture and the story i'm about to tell 498 00:18:42,549 --> 00:18:39,520 you applies to all forms of life 499 00:18:45,909 --> 00:18:42,559 mammals viruses 500 00:18:49,110 --> 00:18:45,919 and everything in between 501 00:18:52,950 --> 00:18:49,120 the complexity richness 502 00:18:57,669 --> 00:18:52,960 and diversity of form and function 503 00:19:00,789 --> 00:18:57,679 of life on earth as we know it 504 00:19:04,230 --> 00:19:00,799 is directly 505 00:19:06,630 --> 00:19:04,240 caused by the fact that 506 00:19:08,549 --> 00:19:06,640 life is made up of complex molecules 507 00:19:11,990 --> 00:19:08,559 living things are made up of complex 508 00:19:13,270 --> 00:19:12,000 molecules if the molecules you had to 509 00:19:15,830 --> 00:19:13,280 build life were simple 510 00:19:18,230 --> 00:19:15,840 like carbon dioxide or water you would 511 00:19:19,350 --> 00:19:18,240 not get this range of diversity richness 512 00:19:21,430 --> 00:19:19,360 or complexity 513 00:19:23,430 --> 00:19:21,440 so here's an example a graphical 514 00:19:24,230 --> 00:19:23,440 representation of a complex molecule 515 00:19:26,150 --> 00:19:24,240 this is 516 00:19:28,029 --> 00:19:26,160 representation of a protein molecule but 517 00:19:30,549 --> 00:19:28,039 of course 518 00:19:32,150 --> 00:19:30,559 deoxyribonucleic acid dna is a very 519 00:19:34,230 --> 00:19:32,160 important complex molecule 520 00:19:35,270 --> 00:19:34,240 for the structure of basic structure of 521 00:19:37,350 --> 00:19:35,280 life and 522 00:19:39,190 --> 00:19:37,360 in this representation every colored 523 00:19:41,270 --> 00:19:39,200 sphere represents a different kind of 524 00:19:42,870 --> 00:19:41,280 atom in the periodic table 525 00:19:46,630 --> 00:19:42,880 so you know you might have carbon 526 00:19:49,430 --> 00:19:46,640 nitrogen oxygen hydrogen helium 527 00:19:50,310 --> 00:19:49,440 these are of course important elements 528 00:19:52,870 --> 00:19:50,320 in these 529 00:19:54,870 --> 00:19:52,880 organic molecules and you know why is it 530 00:19:56,710 --> 00:19:54,880 that it's carbon nitrogen oxygen why not 531 00:19:58,950 --> 00:19:56,720 hydrogen hydrogen is a very common 532 00:20:01,350 --> 00:19:58,960 element why why isn't it so important 533 00:20:03,350 --> 00:20:01,360 hydrogen is important but not nearly as 534 00:20:06,470 --> 00:20:03,360 important as these more complex 535 00:20:08,390 --> 00:20:06,480 heavy atoms it's really cn and o that 536 00:20:09,590 --> 00:20:08,400 are really important carbon nitrogen and 537 00:20:11,510 --> 00:20:09,600 oxygen these are 538 00:20:12,950 --> 00:20:11,520 elements that are present in abundance 539 00:20:15,270 --> 00:20:12,960 here on earth 540 00:20:16,149 --> 00:20:15,280 why am i talking about cn and oh why not 541 00:20:19,669 --> 00:20:16,159 hydrogen 542 00:20:23,270 --> 00:20:19,679 form 543 00:20:25,110 --> 00:20:23,280 one chemical bond so it can be at the 544 00:20:25,990 --> 00:20:25,120 periphery of these large molecules but 545 00:20:30,630 --> 00:20:26,000 it can't be a 546 00:20:33,990 --> 00:20:30,640 these complex molecules 547 00:20:36,870 --> 00:20:34,000 so it's like a one armed atom that 548 00:20:37,430 --> 00:20:36,880 can form hold one hand of the hand of 549 00:20:41,110 --> 00:20:37,440 another 550 00:20:43,750 --> 00:20:41,120 atom helium is a two electron 551 00:20:45,270 --> 00:20:43,760 atom it can it has two hands but it 552 00:20:45,750 --> 00:20:45,280 doesn't like to hold hands with anyone 553 00:20:48,789 --> 00:20:45,760 it's an 554 00:20:49,430 --> 00:20:48,799 inert atom so really lithium beryllium 555 00:20:52,070 --> 00:20:49,440 boron 556 00:20:52,470 --> 00:20:52,080 carbon carbon has six electrons nitrogen 557 00:20:55,029 --> 00:20:52,480 seven 558 00:20:55,669 --> 00:20:55,039 oxygen eight these elements are 559 00:20:57,510 --> 00:20:55,679 important 560 00:20:59,510 --> 00:20:57,520 if we want to understand the origin of 561 00:21:00,710 --> 00:20:59,520 life origin of complex life 562 00:21:02,789 --> 00:21:00,720 and of course these elements are very 563 00:21:04,870 --> 00:21:02,799 common here on earth you know those of 564 00:21:07,669 --> 00:21:04,880 us who are listening to this talk 565 00:21:09,590 --> 00:21:07,679 uh live and indeed those who are going 566 00:21:11,909 --> 00:21:09,600 to listen to this asynchronously 567 00:21:13,590 --> 00:21:11,919 are all breathing in or breathing out 568 00:21:15,350 --> 00:21:13,600 these elements right there's nitrogen 569 00:21:17,029 --> 00:21:15,360 and oxygen in the air we breathe 570 00:21:18,630 --> 00:21:17,039 there's carbon dioxide in the air we 571 00:21:20,789 --> 00:21:18,640 breathe out you know you know 572 00:21:22,390 --> 00:21:20,799 if you went to a barbecue recently you 573 00:21:23,750 --> 00:21:22,400 know you enjoyed the benefits of carbon 574 00:21:25,190 --> 00:21:23,760 if you're wearing a diamond ring 575 00:21:27,110 --> 00:21:25,200 uh you know good for you you're enjoying 576 00:21:29,669 --> 00:21:27,120 the benefits of carbon you know 577 00:21:31,830 --> 00:21:29,679 water in the oceans contain oxygen these 578 00:21:35,350 --> 00:21:31,840 elements are common here on earth 579 00:21:36,470 --> 00:21:35,360 now they're also common in the sun the 580 00:21:38,390 --> 00:21:36,480 sun contains 581 00:21:39,669 --> 00:21:38,400 all of these elements and more in fact 582 00:21:41,430 --> 00:21:39,679 pretty much every element in the 583 00:21:42,230 --> 00:21:41,440 periodic table that's been discovered 584 00:21:45,110 --> 00:21:42,240 here on earth 585 00:21:46,789 --> 00:21:45,120 it's also present in the sun and uh so 586 00:21:49,029 --> 00:21:46,799 it's natural to ask the question 587 00:21:50,149 --> 00:21:49,039 whether the sun's nuclear fusion 588 00:21:52,149 --> 00:21:50,159 reactions 589 00:21:53,909 --> 00:21:52,159 converting hydrogen to helium whether 590 00:21:56,950 --> 00:21:53,919 that fusion reaction 591 00:21:57,669 --> 00:21:56,960 went further and created elements that 592 00:22:00,549 --> 00:21:57,679 we see 593 00:22:01,830 --> 00:22:00,559 and know about in the periodic table so 594 00:22:04,149 --> 00:22:01,840 did the sun 595 00:22:06,149 --> 00:22:04,159 produce these large complex atoms 596 00:22:08,950 --> 00:22:06,159 through nuclear fusion reactions 597 00:22:09,669 --> 00:22:08,960 in its core the simple answer to this 598 00:22:13,350 --> 00:22:09,679 question 599 00:22:15,110 --> 00:22:13,360 is no and this may not come as a 600 00:22:17,669 --> 00:22:15,120 surprise to many of you 601 00:22:19,190 --> 00:22:17,679 but the elements present on earth the 602 00:22:22,789 --> 00:22:19,200 elements 603 00:22:24,950 --> 00:22:22,799 present in the sun were inherited by 604 00:22:25,750 --> 00:22:24,960 these two entities they were inherited 605 00:22:28,390 --> 00:22:25,760 from 606 00:22:29,029 --> 00:22:28,400 the large cloud of gas and dust that the 607 00:22:31,510 --> 00:22:29,039 sun 608 00:22:32,710 --> 00:22:31,520 the earth and the rest of the planets 609 00:22:36,789 --> 00:22:32,720 formed out of 610 00:22:38,310 --> 00:22:36,799 in other words our inheritance consisted 611 00:22:40,149 --> 00:22:38,320 of these wonderful elements in the 612 00:22:42,149 --> 00:22:40,159 periodic table these life-bearing 613 00:22:45,430 --> 00:22:42,159 elements in the periodic table 614 00:22:48,549 --> 00:22:45,440 so of course as a scientist we can't be 615 00:22:50,710 --> 00:22:48,559 we can't stop our search 616 00:22:52,230 --> 00:22:50,720 just at the word inheritance we want to 617 00:22:56,630 --> 00:22:52,240 understand 618 00:22:59,350 --> 00:22:56,640 how or why our ancestors 619 00:23:01,110 --> 00:22:59,360 gave these resources to us the resources 620 00:23:03,990 --> 00:23:01,120 of these wonderful elements 621 00:23:05,350 --> 00:23:04,000 how did they come to be on the earth 622 00:23:05,990 --> 00:23:05,360 well how do they come to be in the 623 00:23:07,750 --> 00:23:06,000 nebula 624 00:23:09,750 --> 00:23:07,760 out of which the sun and earth were 625 00:23:12,070 --> 00:23:09,760 formed well 626 00:23:13,110 --> 00:23:12,080 they came to me in the nebula because of 627 00:23:16,549 --> 00:23:13,120 the sun's 628 00:23:17,510 --> 00:23:16,559 ancestral stars stars that lived and 629 00:23:19,830 --> 00:23:17,520 died 630 00:23:21,590 --> 00:23:19,840 before the sun was even born before the 631 00:23:22,390 --> 00:23:21,600 sun and planets of the solar system were 632 00:23:23,830 --> 00:23:22,400 even born 633 00:23:26,710 --> 00:23:23,840 there were stars like the one in this 634 00:23:30,390 --> 00:23:26,720 picture that 635 00:23:33,350 --> 00:23:30,400 lived and died and produced the elements 636 00:23:35,110 --> 00:23:33,360 that we are you and i are made of now 637 00:23:37,830 --> 00:23:35,120 there are many stars in this picture 638 00:23:38,950 --> 00:23:37,840 and the colors of this particular field 639 00:23:40,149 --> 00:23:38,960 of stars 640 00:23:41,990 --> 00:23:40,159 the colors of the stars in this 641 00:23:43,350 --> 00:23:42,000 particular field reflect something about 642 00:23:45,110 --> 00:23:43,360 their temperature 643 00:23:46,470 --> 00:23:45,120 if you can see my cursor you'll see this 644 00:23:50,470 --> 00:23:46,480 very red star 645 00:23:52,549 --> 00:23:50,480 in the lower left in contrast to a very 646 00:23:53,990 --> 00:23:52,559 blue or bluish white star this one up 647 00:23:56,950 --> 00:23:54,000 here or this one up here 648 00:23:57,590 --> 00:23:56,960 the red stars are much cooler than the 649 00:23:59,590 --> 00:23:57,600 sun 650 00:24:01,350 --> 00:23:59,600 cooler only in a temperature sense the 651 00:24:02,390 --> 00:24:01,360 sun after all is the coolest star in the 652 00:24:04,789 --> 00:24:02,400 whole universe 653 00:24:05,510 --> 00:24:04,799 but these are lower temperature stars i 654 00:24:07,909 --> 00:24:05,520 should say the 655 00:24:08,950 --> 00:24:07,919 red stars and the bluish white stars are 656 00:24:11,350 --> 00:24:08,960 much hotter 657 00:24:12,710 --> 00:24:11,360 stars much higher temperature tens of 658 00:24:16,149 --> 00:24:12,720 thousands of kelvin 659 00:24:19,510 --> 00:24:16,159 on the surface it's these hot stars 660 00:24:21,350 --> 00:24:19,520 that are vigorously 661 00:24:22,549 --> 00:24:21,360 undergoing nuclear fusion reaction in 662 00:24:24,549 --> 00:24:22,559 their centers 663 00:24:25,750 --> 00:24:24,559 much more vigorously than the sun much 664 00:24:27,990 --> 00:24:25,760 more rapidly 665 00:24:29,110 --> 00:24:28,000 so that's one kind of way in which 666 00:24:30,470 --> 00:24:29,120 they're different from the sun 667 00:24:32,870 --> 00:24:30,480 much more vigorous than their nuclear 668 00:24:33,750 --> 00:24:32,880 fusion reaction that vigor translates to 669 00:24:35,909 --> 00:24:33,760 two things 670 00:24:38,870 --> 00:24:35,919 they're able to go through the fusion 671 00:24:40,390 --> 00:24:38,880 reactions much more rapidly than the sun 672 00:24:42,230 --> 00:24:40,400 the sun is going to take 10 billion 673 00:24:44,470 --> 00:24:42,240 years before it produces carbon nitrogen 674 00:24:46,310 --> 00:24:44,480 oxygen it hasn't produced any yet 675 00:24:47,590 --> 00:24:46,320 these stars in less than a million years 676 00:24:48,950 --> 00:24:47,600 the most massive of them 677 00:24:50,950 --> 00:24:48,960 in a million or less than a million 678 00:24:51,590 --> 00:24:50,960 years they can go through and produce 679 00:24:54,310 --> 00:24:51,600 the first 680 00:24:56,789 --> 00:24:54,320 26 elements in the periodic table of 681 00:25:00,149 --> 00:24:56,799 elements the 26th element being iron 682 00:25:04,149 --> 00:25:00,159 fe it can produce those elements 683 00:25:07,669 --> 00:25:04,159 the remarkable thing about these massive 684 00:25:10,950 --> 00:25:07,679 white bluish white massive stars 685 00:25:12,390 --> 00:25:10,960 is they end their lives in spectacular 686 00:25:16,950 --> 00:25:12,400 explosions 687 00:25:17,430 --> 00:25:16,960 of the periodic table are produced 688 00:25:20,230 --> 00:25:17,440 through 689 00:25:21,750 --> 00:25:20,240 neutron bombardment but the wonderful 690 00:25:24,070 --> 00:25:21,760 thing about these explosions 691 00:25:25,830 --> 00:25:24,080 is the elements that were cooked inside 692 00:25:28,070 --> 00:25:25,840 of star through nuclear fusion reactions 693 00:25:29,909 --> 00:25:28,080 are now released to the surroundings so 694 00:25:30,870 --> 00:25:29,919 that the next generation of the stars 695 00:25:33,269 --> 00:25:30,880 can benefit 696 00:25:35,029 --> 00:25:33,279 from what was cooked inside a previous 697 00:25:36,630 --> 00:25:35,039 generation 698 00:25:38,070 --> 00:25:36,640 the story is a little more complicated 699 00:25:40,390 --> 00:25:38,080 than this because 700 00:25:42,149 --> 00:25:40,400 you know you can imagine that yes we 701 00:25:43,830 --> 00:25:42,159 needed to be part of a family of stars 702 00:25:44,230 --> 00:25:43,840 there needed to be other stars exploding 703 00:25:46,470 --> 00:25:44,240 around 704 00:25:47,510 --> 00:25:46,480 us for us to be born out of their ashes 705 00:25:50,950 --> 00:25:47,520 we needed to be 706 00:25:53,269 --> 00:25:50,960 made of stardust but the story is a 707 00:25:54,789 --> 00:25:53,279 little more complicated right so 708 00:25:56,950 --> 00:25:54,799 we needed to be part of a family of 709 00:25:57,669 --> 00:25:56,960 stars family of stars is what we call a 710 00:25:59,830 --> 00:25:57,679 galaxy 711 00:26:01,590 --> 00:25:59,840 but we really need it to be part of a 712 00:26:03,750 --> 00:26:01,600 large galaxy like this one 713 00:26:05,029 --> 00:26:03,760 right this is not our own galaxy this is 714 00:26:06,789 --> 00:26:05,039 a neighbor galaxy 715 00:26:08,630 --> 00:26:06,799 but our milky way galaxy is a large 716 00:26:09,510 --> 00:26:08,640 galaxy just like the galaxy in this 717 00:26:11,590 --> 00:26:09,520 picture 718 00:26:13,190 --> 00:26:11,600 you know and i say large i don't just 719 00:26:15,430 --> 00:26:13,200 mean large in size 720 00:26:17,430 --> 00:26:15,440 i mean it needed to be part of a massive 721 00:26:18,149 --> 00:26:17,440 galaxy a galaxy that contains a lot of 722 00:26:22,390 --> 00:26:18,159 mass 723 00:26:24,230 --> 00:26:22,400 matter the reason why we needed to be 724 00:26:26,549 --> 00:26:24,240 part of a massive galaxy 725 00:26:27,830 --> 00:26:26,559 is because these explosions are so 726 00:26:31,750 --> 00:26:27,840 energetic 727 00:26:34,870 --> 00:26:31,760 that without the gravitational anchor 728 00:26:37,510 --> 00:26:34,880 of a massive host galaxy 729 00:26:39,269 --> 00:26:37,520 the material would have blown right out 730 00:26:41,830 --> 00:26:39,279 of the milky way 731 00:26:42,710 --> 00:26:41,840 and not benefited the next generation of 732 00:26:44,710 --> 00:26:42,720 stars 733 00:26:46,310 --> 00:26:44,720 so we'd be made of the stuff that's 734 00:26:49,110 --> 00:26:46,320 already in our galaxy 735 00:26:51,430 --> 00:26:49,120 not the blown out material enriched 736 00:26:53,029 --> 00:26:51,440 material from previous generations so 737 00:26:55,269 --> 00:26:53,039 the fact that we are stardust in the 738 00:26:56,870 --> 00:26:55,279 world of crosby stills nation young we 739 00:27:00,710 --> 00:26:56,880 are stardust we are golden right 740 00:27:02,230 --> 00:27:00,720 we are that because not just because we 741 00:27:03,990 --> 00:27:02,240 are part of a family of stars but 742 00:27:05,510 --> 00:27:04,000 because we are part of a family of stars 743 00:27:09,669 --> 00:27:05,520 that has so much dark matter 744 00:27:12,310 --> 00:27:09,679 that say that it's able to hold in the 745 00:27:13,909 --> 00:27:12,320 explosion of massive stars now the young 746 00:27:15,029 --> 00:27:13,919 people among you are wondering who 747 00:27:17,430 --> 00:27:15,039 crosby stills 748 00:27:18,230 --> 00:27:17,440 nash and young are they are not a law 749 00:27:19,990 --> 00:27:18,240 firm 750 00:27:21,350 --> 00:27:20,000 they're a rock group they performed at 751 00:27:23,510 --> 00:27:21,360 woodstock and 752 00:27:25,110 --> 00:27:23,520 neil young's girlfriend at the time joni 753 00:27:28,470 --> 00:27:25,120 mitchell 754 00:27:30,310 --> 00:27:28,480 wrote the lyrics to this song now 755 00:27:31,510 --> 00:27:30,320 i said this is a picture of a massive 756 00:27:35,350 --> 00:27:31,520 galaxy 757 00:27:37,190 --> 00:27:35,360 we don't have 758 00:27:39,110 --> 00:27:37,200 a long enough selfie stick to take a 759 00:27:40,950 --> 00:27:39,120 picture of the milky way like this 760 00:27:43,110 --> 00:27:40,960 so what we have to do instead is we have 761 00:27:46,230 --> 00:27:43,120 to look out of our window 762 00:27:48,470 --> 00:27:46,240 and see a neighbor's 763 00:27:50,630 --> 00:27:48,480 house we can't see our own house because 764 00:27:53,350 --> 00:27:50,640 we've been stuck inside it forever 765 00:27:55,029 --> 00:27:53,360 if this were the milky way we don't live 766 00:27:58,070 --> 00:27:55,039 in downtown milky way 767 00:27:58,630 --> 00:27:58,080 we don't live in rural milky way we sort 768 00:28:01,110 --> 00:27:58,640 of live 769 00:28:03,269 --> 00:28:01,120 in suburbia had this been an image of 770 00:28:07,190 --> 00:28:03,279 the milky way we would be about there 771 00:28:08,870 --> 00:28:07,200 we live about 25 000 772 00:28:10,549 --> 00:28:08,880 light years from the center of the milky 773 00:28:12,789 --> 00:28:10,559 way this whole picture 774 00:28:15,110 --> 00:28:12,799 is about a hundred thousand light years 775 00:28:18,230 --> 00:28:15,120 across 776 00:28:18,789 --> 00:28:18,240 you know 25 000 years of light travel 777 00:28:21,269 --> 00:28:18,799 time 778 00:28:23,190 --> 00:28:21,279 from the center of the milky way to our 779 00:28:25,110 --> 00:28:23,200 solar system's location 780 00:28:26,630 --> 00:28:25,120 you know if if this were the milky way 781 00:28:28,389 --> 00:28:26,640 and i tried to show you a picture of the 782 00:28:29,110 --> 00:28:28,399 solar system it would be smaller than a 783 00:28:31,029 --> 00:28:29,120 pixel 784 00:28:32,870 --> 00:28:31,039 our solar system would be so small just 785 00:28:35,909 --> 00:28:32,880 to give you a sense of scale 786 00:28:39,350 --> 00:28:35,919 light travels across our solar system 787 00:28:41,750 --> 00:28:39,360 in about a day it travels from the sun 788 00:28:44,549 --> 00:28:41,760 to the earth in about eight minutes 789 00:28:45,510 --> 00:28:44,559 from the moon to the earth in about a 790 00:28:47,430 --> 00:28:45,520 second 791 00:28:49,110 --> 00:28:47,440 light travels around the world seven 792 00:28:51,590 --> 00:28:49,120 times in one second 793 00:28:54,470 --> 00:28:51,600 traveling at that speed light takes a 794 00:28:56,950 --> 00:28:54,480 hundred thousand years to get across 795 00:28:58,870 --> 00:28:56,960 this section of the andromeda galaxy the 796 00:29:01,190 --> 00:28:58,880 section that's shown in this picture 797 00:29:03,029 --> 00:29:01,200 i say this section because i'll tell you 798 00:29:04,870 --> 00:29:03,039 in a minute how the andromeda galaxy is 799 00:29:07,110 --> 00:29:04,880 much bigger than this rectangle than 800 00:29:09,430 --> 00:29:07,120 this red rectangle can hold 801 00:29:11,430 --> 00:29:09,440 now this is of course not our home 802 00:29:13,590 --> 00:29:11,440 galaxy it's the andromeda galaxy we have 803 00:29:15,110 --> 00:29:13,600 a very strange view of our own galaxy 804 00:29:17,269 --> 00:29:15,120 it's like trying to look at your own 805 00:29:19,669 --> 00:29:17,279 face without a mirror you can squint you 806 00:29:22,389 --> 00:29:19,679 can see a part of your nose perhaps 807 00:29:23,830 --> 00:29:22,399 you can see your own spectacles you know 808 00:29:25,350 --> 00:29:23,840 you might see your 809 00:29:27,110 --> 00:29:25,360 you know bit of mustache if you have a 810 00:29:28,710 --> 00:29:27,120 lot of you know a lot of that 811 00:29:31,029 --> 00:29:28,720 but you really have to squint to see 812 00:29:34,149 --> 00:29:31,039 your own face in the same way 813 00:29:37,430 --> 00:29:34,159 we have a very strange view of our own 814 00:29:39,750 --> 00:29:37,440 galaxy our milky way galaxy 815 00:29:41,830 --> 00:29:39,760 looks like this from our perspective you 816 00:29:44,870 --> 00:29:41,840 know this band of light across the 817 00:29:46,870 --> 00:29:44,880 bottom band of light and gas and dust 818 00:29:48,710 --> 00:29:46,880 this was imaged by one of my friends 819 00:29:49,830 --> 00:29:48,720 john rockman at castle air school in 820 00:29:52,310 --> 00:29:49,840 palo alto 821 00:29:54,149 --> 00:29:52,320 and he took not one image but a series 822 00:29:55,029 --> 00:29:54,159 of wide-angle images i'm going to remove 823 00:29:59,190 --> 00:29:55,039 the label 824 00:30:02,070 --> 00:29:59,200 and play this time lapse for you as 825 00:30:03,990 --> 00:30:02,080 the sun sets the sky gets darker as the 826 00:30:07,510 --> 00:30:04,000 earth's rotation 827 00:30:10,470 --> 00:30:07,520 takes place the milky way appears 828 00:30:11,110 --> 00:30:10,480 to sweep across the sky you see 829 00:30:15,190 --> 00:30:11,120 lightning 830 00:30:17,590 --> 00:30:15,200 shooting stars clouds the fluttering of 831 00:30:19,430 --> 00:30:17,600 tree leaves of the tree and the breeze 832 00:30:21,029 --> 00:30:19,440 i'll play this one more time for you 833 00:30:23,350 --> 00:30:21,039 at the beginning of this movie the sky 834 00:30:25,350 --> 00:30:23,360 is still getting dark after sunset 835 00:30:27,510 --> 00:30:25,360 but slowly the sky gets darker and we 836 00:30:30,070 --> 00:30:27,520 see our grand home the milky way 837 00:30:30,870 --> 00:30:30,080 frisbee shaped milky way that's viewed 838 00:30:33,750 --> 00:30:30,880 from our 839 00:30:35,269 --> 00:30:33,760 perspective within that frisbee we are 840 00:30:37,430 --> 00:30:35,279 in the plane of the milky way which is 841 00:30:40,149 --> 00:30:37,440 why it looks like a band of light 842 00:30:41,590 --> 00:30:40,159 a line of light across the sky in fact 843 00:30:44,789 --> 00:30:41,600 the word milky 844 00:30:47,110 --> 00:30:44,799 way via lactair uh 845 00:30:48,870 --> 00:30:47,120 comes from the appearance of our milky 846 00:30:49,510 --> 00:30:48,880 way you know the band of light across 847 00:30:51,029 --> 00:30:49,520 the sky 848 00:30:53,830 --> 00:30:51,039 but i just wanted to point out that the 849 00:30:55,350 --> 00:30:53,840 word galaxy the word galaxy is related 850 00:30:58,389 --> 00:30:55,360 to the greek word for milk 851 00:31:00,870 --> 00:30:58,399 galacto lacto so we've named 852 00:31:02,710 --> 00:31:00,880 our every galaxy after the appearance of 853 00:31:05,590 --> 00:31:02,720 our own after the milky appearance 854 00:31:07,350 --> 00:31:05,600 of our own you know there we go so 855 00:31:09,909 --> 00:31:07,360 that's our milky way 856 00:31:10,630 --> 00:31:09,919 now you know for a long time you know 857 00:31:13,350 --> 00:31:10,640 going back 858 00:31:15,350 --> 00:31:13,360 hundreds of years people speculated 859 00:31:16,950 --> 00:31:15,360 about the nature of these things we now 860 00:31:18,950 --> 00:31:16,960 call galaxies 861 00:31:20,070 --> 00:31:18,960 this goes back to a very famous 862 00:31:24,230 --> 00:31:20,080 philosopher 863 00:31:28,470 --> 00:31:24,240 emmanuel kant who coined the term 864 00:31:29,750 --> 00:31:28,480 island universe in 1755. we're talking 865 00:31:33,110 --> 00:31:29,760 about 866 00:31:35,029 --> 00:31:33,120 you know a quarter of a millennium ago 867 00:31:37,990 --> 00:31:35,039 250 years ago 868 00:31:39,269 --> 00:31:38,000 um kant posted this selfie at some point 869 00:31:42,149 --> 00:31:39,279 around that time 870 00:31:43,350 --> 00:31:42,159 and this is a quote from him you know 871 00:31:47,029 --> 00:31:43,360 about 872 00:31:50,310 --> 00:31:47,039 how he pondered the nature of 873 00:31:53,590 --> 00:31:50,320 these islands of light 874 00:31:59,190 --> 00:31:56,549 kant lived in a very small town in what 875 00:32:01,909 --> 00:31:59,200 was then prussia 876 00:32:03,830 --> 00:32:01,919 koenigsberg i forget the new name for it 877 00:32:05,029 --> 00:32:03,840 it's in russia now i forget the new name 878 00:32:07,430 --> 00:32:05,039 of koenigsberg i've 879 00:32:08,950 --> 00:32:07,440 i've looked it up before i was once 880 00:32:10,389 --> 00:32:08,960 giving a talk and there was a person in 881 00:32:12,230 --> 00:32:10,399 the audience who was from that town 882 00:32:14,630 --> 00:32:12,240 that's the only other person i've 883 00:32:16,710 --> 00:32:14,640 come across from koenigsberg prussia 884 00:32:19,669 --> 00:32:16,720 what was called koenigsberg pressure 885 00:32:21,269 --> 00:32:19,679 now kant of course deflected this 886 00:32:23,669 --> 00:32:21,279 wonderful term 887 00:32:25,750 --> 00:32:23,679 um when he was given credit for uh the 888 00:32:27,509 --> 00:32:25,760 term island universe he said no no this 889 00:32:28,630 --> 00:32:27,519 term came from other people it came from 890 00:32:30,870 --> 00:32:28,640 people before me 891 00:32:31,909 --> 00:32:30,880 he credited this to thomas wright and 892 00:32:34,710 --> 00:32:31,919 william herschel 893 00:32:35,190 --> 00:32:34,720 but most people credit can't with the 894 00:32:38,470 --> 00:32:35,200 term 895 00:32:41,509 --> 00:32:38,480 island universe so this was really 896 00:32:41,750 --> 00:32:41,519 a philosopher's view of how the universe 897 00:32:46,470 --> 00:32:41,760 is 898 00:32:49,750 --> 00:32:46,480 important 899 00:32:51,029 --> 00:32:49,760 um sort of discussion about the nature 900 00:32:53,269 --> 00:32:51,039 of the universe and 901 00:32:56,870 --> 00:32:53,279 kant is a you know i would argue one of 902 00:32:58,789 --> 00:32:56,880 the most famous philosophers of all time 903 00:33:01,190 --> 00:32:58,799 certainly the most famous philosopher to 904 00:33:04,070 --> 00:33:01,200 ever come out of koenigsberg pressure 905 00:33:05,190 --> 00:33:04,080 but the sad thing is he applied for a 906 00:33:07,590 --> 00:33:05,200 faculty position 907 00:33:09,350 --> 00:33:07,600 in the philosophy department of the 908 00:33:11,269 --> 00:33:09,360 university of konigsberg 909 00:33:12,950 --> 00:33:11,279 and for the first first time he applied 910 00:33:14,470 --> 00:33:12,960 they turned him down you know imagine 911 00:33:15,430 --> 00:33:14,480 that they turned him down the university 912 00:33:17,029 --> 00:33:15,440 really blew it 913 00:33:19,110 --> 00:33:17,039 it turns out he applied a second time 914 00:33:19,750 --> 00:33:19,120 and he got the job but it makes me feel 915 00:33:22,230 --> 00:33:19,760 very bad 916 00:33:23,190 --> 00:33:22,240 as a faculty member especially now as 917 00:33:25,590 --> 00:33:23,200 department chairs 918 00:33:26,470 --> 00:33:25,600 i'm hiring new faculty makes all of us 919 00:33:30,149 --> 00:33:26,480 faculty feel 920 00:33:32,230 --> 00:33:30,159 really uh guilty that here we were we 921 00:33:33,269 --> 00:33:32,240 were given faculty positions at uc santa 922 00:33:35,990 --> 00:33:33,279 cruz or 923 00:33:38,149 --> 00:33:36,000 wherever we are but this great 924 00:33:39,830 --> 00:33:38,159 philosopher the greatest of all time was 925 00:33:41,110 --> 00:33:39,840 turned down for a faculty position the 926 00:33:43,269 --> 00:33:41,120 first time around 927 00:33:45,830 --> 00:33:43,279 and one of my colleagues speculated that 928 00:33:47,590 --> 00:33:45,840 you know when you hire a faculty person 929 00:33:49,269 --> 00:33:47,600 you have to not just put aside money for 930 00:33:51,430 --> 00:33:49,279 their salary you have to put aside money 931 00:33:53,669 --> 00:33:51,440 for them to do research so they're given 932 00:33:54,470 --> 00:33:53,679 startup grants you know startup packages 933 00:33:56,549 --> 00:33:54,480 that 934 00:33:58,789 --> 00:33:56,559 with which you an astronomer might go 935 00:34:00,310 --> 00:33:58,799 off and either build a telescope or buy 936 00:34:02,470 --> 00:34:00,320 into a telescope project 937 00:34:03,669 --> 00:34:02,480 a physicist might set up a lab a chemist 938 00:34:06,230 --> 00:34:03,679 might set up a lab 939 00:34:08,149 --> 00:34:06,240 if you're a theoretical physicist your 940 00:34:10,069 --> 00:34:08,159 startup funds can be limited because all 941 00:34:13,909 --> 00:34:10,079 you need to buy are a desk 942 00:34:16,149 --> 00:34:13,919 a chair a notepad a pencil 943 00:34:17,750 --> 00:34:16,159 and a wastebasket if you're a 944 00:34:19,589 --> 00:34:17,760 philosopher you don't even need the 945 00:34:24,710 --> 00:34:19,599 waste basket 946 00:34:27,829 --> 00:34:24,720 anyway moving on kant's work 947 00:34:29,990 --> 00:34:27,839 was largely forgotten for 948 00:34:32,869 --> 00:34:30,000 almost 100 years after his death you 949 00:34:34,710 --> 00:34:32,879 know so he died in 1804 950 00:34:38,389 --> 00:34:34,720 in the early 1900s in the beginning of 951 00:34:44,069 --> 00:34:42,470 the notion of island universes started 952 00:34:48,470 --> 00:34:44,079 to resurface 953 00:34:52,389 --> 00:34:48,480 through the work of two astronomers 954 00:34:56,470 --> 00:34:52,399 sharply and curtis curtis and sharply 955 00:35:00,150 --> 00:34:56,480 curtis was of the opinion that these 956 00:35:02,069 --> 00:35:00,160 islands of light were 957 00:35:03,589 --> 00:35:02,079 galaxies just like the milky way you 958 00:35:05,829 --> 00:35:03,599 know the milky way is a galaxy 959 00:35:07,670 --> 00:35:05,839 these little islands are just distant 960 00:35:09,190 --> 00:35:07,680 galaxies that look like tiny 961 00:35:12,790 --> 00:35:09,200 islands but they're actually as big as 962 00:35:15,430 --> 00:35:12,800 the milky way and shapley said no 963 00:35:15,990 --> 00:35:15,440 those things are inside our milky way 964 00:35:18,630 --> 00:35:16,000 galaxy 965 00:35:20,870 --> 00:35:18,640 those nebulae those island universes 966 00:35:21,829 --> 00:35:20,880 that can't talk about are within our 967 00:35:25,589 --> 00:35:21,839 milky way 968 00:35:28,390 --> 00:35:25,599 inside 969 00:35:30,069 --> 00:35:28,400 um so there was this big debate in the 970 00:35:32,630 --> 00:35:30,079 early 1900s 971 00:35:33,190 --> 00:35:32,640 curtis turns out was right he was right 972 00:35:35,670 --> 00:35:33,200 that those 973 00:35:37,030 --> 00:35:35,680 nebulae that can't refer to as alien 974 00:35:38,870 --> 00:35:37,040 universes were really 975 00:35:40,870 --> 00:35:38,880 uh are the galaxies like the milky way 976 00:35:43,030 --> 00:35:40,880 sharply got it wrong shapley had 977 00:35:43,990 --> 00:35:43,040 made a mistake um you know not not 978 00:35:46,310 --> 00:35:44,000 through any 979 00:35:47,349 --> 00:35:46,320 fault of his but had misestimated the 980 00:35:49,990 --> 00:35:47,359 distances to 981 00:35:51,349 --> 00:35:50,000 globular clusters so we had an incorrect 982 00:35:53,589 --> 00:35:51,359 notion about 983 00:35:55,109 --> 00:35:53,599 how big our milky way was now time 984 00:35:56,630 --> 00:35:55,119 magazine got this 985 00:35:58,230 --> 00:35:56,640 completely reversed and they put the 986 00:36:00,150 --> 00:35:58,240 wrong person on the cover of time 987 00:36:02,069 --> 00:36:00,160 magazine they put harlow shapley 988 00:36:04,470 --> 00:36:02,079 on the cover harvard's hollow sharply it 989 00:36:07,030 --> 00:36:04,480 says on the cover of time magazine 990 00:36:08,550 --> 00:36:07,040 and um of course you know they're not 991 00:36:10,069 --> 00:36:08,560 going to put a second astronomer on the 992 00:36:13,430 --> 00:36:10,079 cover in the next issue 993 00:36:15,910 --> 00:36:13,440 so to poke fun at themselves uh they 994 00:36:18,230 --> 00:36:15,920 a few months later they had this issue 995 00:36:20,630 --> 00:36:18,240 of time magazine a much more 996 00:36:21,430 --> 00:36:20,640 typical time magazine cover where they 997 00:36:24,870 --> 00:36:21,440 had um 998 00:36:28,870 --> 00:36:24,880 an entertainer gene harlow on the cover 999 00:36:31,430 --> 00:36:28,880 now notice her last name harlow 1000 00:36:32,150 --> 00:36:31,440 written right there under her picture is 1001 00:36:34,470 --> 00:36:32,160 the same 1002 00:36:35,349 --> 00:36:34,480 as his first name harlow so they were 1003 00:36:38,230 --> 00:36:35,359 sort of poking 1004 00:36:39,670 --> 00:36:38,240 fun at their own mistake and apparently 1005 00:36:42,630 --> 00:36:39,680 inside the magazine 1006 00:36:43,670 --> 00:36:42,640 they referred to her as the shapely 1007 00:36:46,550 --> 00:36:43,680 harlow 1008 00:36:47,750 --> 00:36:46,560 which was a direct play on words on the 1009 00:36:50,470 --> 00:36:47,760 name of harlow 1010 00:36:50,950 --> 00:36:50,480 sharply anyway this story was told to be 1011 00:36:54,630 --> 00:36:50,960 my 1012 00:36:56,230 --> 00:36:54,640 rich god i don't know how he knew about 1013 00:36:58,230 --> 00:36:56,240 the story but i actually looked up these 1014 00:37:00,550 --> 00:36:58,240 covers and found them online 1015 00:37:01,430 --> 00:37:00,560 so back to thinking about island 1016 00:37:05,910 --> 00:37:01,440 universes 1017 00:37:08,150 --> 00:37:05,920 this debate got rejuvenated in the 1900s 1018 00:37:10,390 --> 00:37:08,160 and it remained open as to how much 1019 00:37:11,829 --> 00:37:10,400 empty space there is between galaxies 1020 00:37:13,670 --> 00:37:11,839 now that you've established that these 1021 00:37:15,349 --> 00:37:13,680 island universes are indeed islands 1022 00:37:17,829 --> 00:37:15,359 how much ocean is there between these 1023 00:37:20,150 --> 00:37:17,839 islands so this is a question that 1024 00:37:21,190 --> 00:37:20,160 my group and i got very interested in 1025 00:37:24,390 --> 00:37:21,200 over the years 1026 00:37:25,589 --> 00:37:24,400 and here's a picture we took my students 1027 00:37:28,069 --> 00:37:25,599 and i took 1028 00:37:29,670 --> 00:37:28,079 of the andromeda galaxy so this is 1029 00:37:31,190 --> 00:37:29,680 really at that time it was the first 1030 00:37:34,390 --> 00:37:31,200 digital mosaic 1031 00:37:35,670 --> 00:37:34,400 of the andromeda galaxy the mosaic was 1032 00:37:38,630 --> 00:37:35,680 stitched by my 1033 00:37:39,349 --> 00:37:38,640 students um andreas berlind and phil 1034 00:37:41,109 --> 00:37:39,359 choi 1035 00:37:42,550 --> 00:37:41,119 and shimakura choudhury and i did the 1036 00:37:44,390 --> 00:37:42,560 original observations these are four 1037 00:37:45,910 --> 00:37:44,400 images of the andromeda galaxy 1038 00:37:47,430 --> 00:37:45,920 at four different contrast levels you 1039 00:37:48,950 --> 00:37:47,440 see the highest contrast on the right 1040 00:37:50,310 --> 00:37:48,960 lowest contrast on the left 1041 00:37:52,150 --> 00:37:50,320 and if you look closely you can see one 1042 00:37:54,870 --> 00:37:52,160 of the companions of andromeda 1043 00:37:55,589 --> 00:37:54,880 m32 another companion peeking in from 1044 00:37:58,470 --> 00:37:55,599 the left 1045 00:37:59,030 --> 00:37:58,480 as we go to higher contrast ngc 205 uh 1046 00:38:01,589 --> 00:37:59,040 here's 1047 00:38:02,950 --> 00:38:01,599 another image of andromeda this one's 1048 00:38:06,150 --> 00:38:02,960 taken by robert gendler 1049 00:38:08,069 --> 00:38:06,160 beautiful image this time of andromeda 1050 00:38:09,589 --> 00:38:08,079 in a different orientation and two of 1051 00:38:11,670 --> 00:38:09,599 its satellite galaxies two small 1052 00:38:14,950 --> 00:38:11,680 galaxies that are being cannibalized 1053 00:38:15,349 --> 00:38:14,960 by andromeda now for my research our 1054 00:38:19,349 --> 00:38:15,359 group 1055 00:38:22,150 --> 00:38:19,359 uses his privileged to use 1056 00:38:22,790 --> 00:38:22,160 the keck telescope on the sacred 1057 00:38:27,430 --> 00:38:22,800 mountain 1058 00:38:31,270 --> 00:38:27,440 of mauna kea on the big island of hawaii 1059 00:38:33,670 --> 00:38:31,280 this is a sacred mountain to 1060 00:38:35,430 --> 00:38:33,680 many generations of people who lived on 1061 00:38:35,990 --> 00:38:35,440 the island who have looked up to the 1062 00:38:39,430 --> 00:38:36,000 skies 1063 00:38:41,270 --> 00:38:39,440 for inspiration and worshiped the gods 1064 00:38:43,589 --> 00:38:41,280 and we astronomers are very privileged 1065 00:38:45,990 --> 00:38:43,599 to have use of that 1066 00:38:47,750 --> 00:38:46,000 mountaintop to use modern telescopes to 1067 00:38:50,950 --> 00:38:47,760 continue the search for 1068 00:38:51,270 --> 00:38:50,960 our place in the universe so this photo 1069 00:38:53,109 --> 00:38:51,280 of 1070 00:38:55,109 --> 00:38:53,119 the mauna kea summit with the two keck 1071 00:38:56,230 --> 00:38:55,119 telescopes was taken by lori hatch on a 1072 00:38:58,790 --> 00:38:56,240 beautiful 1073 00:39:00,710 --> 00:38:58,800 big island sunset and you have andromeda 1074 00:39:03,670 --> 00:39:00,720 and its two satellites 1075 00:39:05,510 --> 00:39:03,680 in the background of this image we also 1076 00:39:06,790 --> 00:39:05,520 use the hubble space telescope my 1077 00:39:08,150 --> 00:39:06,800 collaborators and i have 1078 00:39:10,230 --> 00:39:08,160 used the hubble space telescope 1079 00:39:12,710 --> 00:39:10,240 extensively to study 1080 00:39:14,150 --> 00:39:12,720 the andromeda galaxy if you could see 1081 00:39:16,950 --> 00:39:14,160 the andromeda galaxy 1082 00:39:19,349 --> 00:39:16,960 with powerful binoculars you'd see that 1083 00:39:21,910 --> 00:39:19,359 it's actually more extended 1084 00:39:23,349 --> 00:39:21,920 in apparent extent than the full moon 1085 00:39:25,270 --> 00:39:23,359 there's the full moon to scale 1086 00:39:26,390 --> 00:39:25,280 the andromeda galaxy the full moon is 1087 00:39:28,390 --> 00:39:26,400 half a degree across 1088 00:39:29,510 --> 00:39:28,400 this portion of the andromeda galaxy is 1089 00:39:32,230 --> 00:39:29,520 a few degrees 1090 00:39:33,829 --> 00:39:32,240 across at least along the long axis and 1091 00:39:36,550 --> 00:39:33,839 about half a degree across 1092 00:39:37,270 --> 00:39:36,560 along the short axis of this ellipse 1093 00:39:39,589 --> 00:39:37,280 this 1094 00:39:40,950 --> 00:39:39,599 white outline that you typically draw 1095 00:39:44,069 --> 00:39:40,960 around a crime scene 1096 00:39:45,510 --> 00:39:44,079 this white outline is not the chalk mark 1097 00:39:48,069 --> 00:39:45,520 of a crime scene but it's the 1098 00:39:49,829 --> 00:39:48,079 region of the andromeda galaxy in which 1099 00:39:52,390 --> 00:39:49,839 a modern digital 1100 00:39:54,069 --> 00:39:52,400 mosaic was constructed i mentioned the 1101 00:39:55,030 --> 00:39:54,079 first digital mosaic of my students and 1102 00:39:59,270 --> 00:39:55,040 i made with 1103 00:40:01,030 --> 00:39:59,280 57 images this one we used 3 000 images 1104 00:40:03,030 --> 00:40:01,040 with the hubble space telescope 1105 00:40:05,190 --> 00:40:03,040 a project called the panchromatic hubble 1106 00:40:07,030 --> 00:40:05,200 andromeda treasury led by 1107 00:40:08,790 --> 00:40:07,040 my wonderful colleague julian del canton 1108 00:40:11,109 --> 00:40:08,800 at the university of washington 1109 00:40:12,390 --> 00:40:11,119 and our group at ucsc used the cat 1110 00:40:14,470 --> 00:40:12,400 telescope that you saw in the last 1111 00:40:17,589 --> 00:40:14,480 picture to take spectrostars 1112 00:40:19,030 --> 00:40:17,599 now in the next few years 1113 00:40:21,109 --> 00:40:19,040 there's going to be another wonderful 1114 00:40:23,910 --> 00:40:21,119 telescope put out by nasa 1115 00:40:24,870 --> 00:40:23,920 it's called the nancy grace roman space 1116 00:40:29,109 --> 00:40:24,880 telescope 1117 00:40:31,430 --> 00:40:29,119 and it will have the imaging capability 1118 00:40:32,470 --> 00:40:31,440 of more than a hundred hubble space 1119 00:40:35,670 --> 00:40:32,480 telescopes 1120 00:40:37,109 --> 00:40:35,680 what took three thousand images to cover 1121 00:40:40,069 --> 00:40:37,119 with hubble 1122 00:40:41,589 --> 00:40:40,079 what's shown in this blue outline here 1123 00:40:43,589 --> 00:40:41,599 will be covered with 1124 00:40:45,670 --> 00:40:43,599 two or three pointings with the nancy 1125 00:40:47,829 --> 00:40:45,680 grace ramen telescope 1126 00:40:49,030 --> 00:40:47,839 so it's going to be a supremely powerful 1127 00:40:51,750 --> 00:40:49,040 telescope 1128 00:40:53,910 --> 00:40:51,760 in terms of how much area it can cover 1129 00:40:56,710 --> 00:40:53,920 at one shot so i can't wait 1130 00:40:58,950 --> 00:40:56,720 to see this come to and the the the 1131 00:41:00,230 --> 00:40:58,960 footprint of a single pointing with the 1132 00:41:03,510 --> 00:41:00,240 roman telescope 1133 00:41:06,550 --> 00:41:03,520 is shown in in in the form of these 1134 00:41:07,190 --> 00:41:06,560 small squares one two three multiplied 1135 00:41:11,190 --> 00:41:07,200 by six 1136 00:41:11,750 --> 00:41:11,200 these 18 uh mosaic 18 element mosaic 1137 00:41:13,589 --> 00:41:11,760 camera 1138 00:41:15,430 --> 00:41:13,599 is what the roman space telescope will 1139 00:41:16,390 --> 00:41:15,440 use that's a grace roman space telescope 1140 00:41:19,750 --> 00:41:16,400 will use 1141 00:41:21,190 --> 00:41:19,760 now i will zoom in on the hubble image 1142 00:41:21,670 --> 00:41:21,200 the hubble mosaic because the nancy 1143 00:41:23,910 --> 00:41:21,680 grace 1144 00:41:24,950 --> 00:41:23,920 roman telescope hasn't been launched yet 1145 00:41:27,030 --> 00:41:24,960 it's not yet in orbit 1146 00:41:28,230 --> 00:41:27,040 so i'll show you an image taken with the 1147 00:41:29,109 --> 00:41:28,240 hubble space telescope we're going to 1148 00:41:30,710 --> 00:41:29,119 zoom in 1149 00:41:32,710 --> 00:41:30,720 so those of you who are watching this at 1150 00:41:35,750 --> 00:41:32,720 home please fasten your seat belts 1151 00:41:37,670 --> 00:41:35,760 as we zoom in i'm going to remove the 1152 00:41:40,950 --> 00:41:37,680 label so you can focus on the image 1153 00:41:41,990 --> 00:41:40,960 and not on the label and what we're 1154 00:41:44,309 --> 00:41:42,000 going to see 1155 00:41:46,790 --> 00:41:44,319 is this is the arc of the milky way 1156 00:41:49,109 --> 00:41:46,800 galaxy with gas and dust the dark back 1157 00:41:50,630 --> 00:41:49,119 bands are dust there's andromeda two and 1158 00:41:51,750 --> 00:41:50,640 a half million light years away and 1159 00:41:53,190 --> 00:41:51,760 we're going to zoom in we're going to 1160 00:41:54,870 --> 00:41:53,200 zoom in a long way 1161 00:41:56,550 --> 00:41:54,880 so you can see a lot of the details of 1162 00:41:58,710 --> 00:41:56,560 andromeda and it's two satellites you 1163 00:42:01,349 --> 00:41:58,720 just saw the two satellites go by there 1164 00:42:01,990 --> 00:42:01,359 we're going to zoom in so much that 1165 00:42:06,230 --> 00:42:02,000 you'll be able 1166 00:42:08,230 --> 00:42:06,240 to see individual stars 1167 00:42:10,150 --> 00:42:08,240 imaged with the hubble space telescope 1168 00:42:11,109 --> 00:42:10,160 individual stars that have different 1169 00:42:13,430 --> 00:42:11,119 colors 1170 00:42:14,710 --> 00:42:13,440 some are very hot and they look bluish 1171 00:42:18,150 --> 00:42:14,720 white in this image 1172 00:42:19,030 --> 00:42:18,160 some are very cool they look reddish or 1173 00:42:21,910 --> 00:42:19,040 orange 1174 00:42:24,630 --> 00:42:21,920 in this picture and you even see these 1175 00:42:26,550 --> 00:42:24,640 dark bands of gas and dust 1176 00:42:28,870 --> 00:42:26,560 just like you see in the milky way 1177 00:42:31,190 --> 00:42:28,880 pictures like this convince us that the 1178 00:42:33,190 --> 00:42:31,200 detailed structure of andromeda 1179 00:42:34,390 --> 00:42:33,200 is no different from the detailed 1180 00:42:37,670 --> 00:42:34,400 structure of our own 1181 00:42:40,470 --> 00:42:37,680 milky way galaxy so 1182 00:42:42,309 --> 00:42:40,480 my group has used this these images to 1183 00:42:44,950 --> 00:42:42,319 carry out very detailed studies 1184 00:42:46,390 --> 00:42:44,960 of the andromeda galaxy one of the 1185 00:42:49,750 --> 00:42:46,400 things i just talked about 1186 00:42:51,990 --> 00:42:49,760 is galaxies cannibalize each other 1187 00:42:53,910 --> 00:42:52,000 andromeda is swallowing 1188 00:42:56,150 --> 00:42:53,920 two of its satellites so let's look at 1189 00:42:58,550 --> 00:42:56,160 what galaxy collisions 1190 00:42:59,349 --> 00:42:58,560 or cannibalism looks like galaxy 1191 00:43:01,430 --> 00:42:59,359 cannibalism 1192 00:43:04,790 --> 00:43:01,440 lasts for a very long time a single 1193 00:43:07,109 --> 00:43:04,800 snack lasts for a billion years 1194 00:43:09,589 --> 00:43:07,119 or a few billion years so i'm going to 1195 00:43:12,309 --> 00:43:09,599 speed this up with computer simulations 1196 00:43:13,670 --> 00:43:12,319 of galaxy collisions compared to actual 1197 00:43:16,390 --> 00:43:13,680 snapshots 1198 00:43:17,430 --> 00:43:16,400 of galaxies different pairs of galaxies 1199 00:43:19,670 --> 00:43:17,440 caught in the act 1200 00:43:21,510 --> 00:43:19,680 of cannibalism so again i'm going to 1201 00:43:24,870 --> 00:43:21,520 remove my label so you can focus 1202 00:43:25,750 --> 00:43:24,880 on the video itself and here are two 1203 00:43:32,309 --> 00:43:25,760 galaxies 1204 00:43:33,670 --> 00:43:32,319 as they come together we stop the 1205 00:43:36,309 --> 00:43:33,680 computer simulation 1206 00:43:37,270 --> 00:43:36,319 and here are two real disc galaxies that 1207 00:43:39,750 --> 00:43:37,280 are about 1208 00:43:40,550 --> 00:43:39,760 to collide we go back to the computer 1209 00:43:42,710 --> 00:43:40,560 simulation 1210 00:43:44,870 --> 00:43:42,720 their mutual gravity draws them ever 1211 00:43:46,630 --> 00:43:44,880 closer and they start to intersect the 1212 00:43:47,829 --> 00:43:46,640 two galaxies are actually intersecting 1213 00:43:50,550 --> 00:43:47,839 each other at this point 1214 00:43:52,309 --> 00:43:50,560 the way we can tell they're intersecting 1215 00:43:54,550 --> 00:43:52,319 these two model galaxies if we change 1216 00:43:56,309 --> 00:43:54,560 our perspective you stop the simulation 1217 00:43:58,069 --> 00:43:56,319 change our perspective here are two real 1218 00:43:59,990 --> 00:43:58,079 galaxies that are intersecting 1219 00:44:01,990 --> 00:44:00,000 different pair than the first two the 1220 00:44:03,750 --> 00:44:02,000 two galaxies computer simulated galaxies 1221 00:44:05,109 --> 00:44:03,760 start to stretch each other out through 1222 00:44:07,190 --> 00:44:05,119 their differential gravity 1223 00:44:08,230 --> 00:44:07,200 tidal forces stop the computer 1224 00:44:10,150 --> 00:44:08,240 simulation here 1225 00:44:11,670 --> 00:44:10,160 are two real galaxies that are further 1226 00:44:13,270 --> 00:44:11,680 along in the collision process that are 1227 00:44:15,750 --> 00:44:13,280 stretching each other out 1228 00:44:17,349 --> 00:44:15,760 the main bodies of the simulated galaxy 1229 00:44:20,550 --> 00:44:17,359 start to fall back together again 1230 00:44:22,710 --> 00:44:20,560 again due to their gravity and right 1231 00:44:24,390 --> 00:44:22,720 before the two main bodies merge we stop 1232 00:44:27,030 --> 00:44:24,400 the computer simulation 1233 00:44:27,430 --> 00:44:27,040 change our perspective one more time and 1234 00:44:30,870 --> 00:44:27,440 here 1235 00:44:31,589 --> 00:44:30,880 are very far along in the collision 1236 00:44:33,510 --> 00:44:31,599 process 1237 00:44:35,750 --> 00:44:33,520 the two main bodies of the galaxies now 1238 00:44:35,990 --> 00:44:35,760 merge the black holes at their centers 1239 00:44:39,109 --> 00:44:36,000 will 1240 00:44:40,790 --> 00:44:39,119 ultimately merge produce gravitational 1241 00:44:42,790 --> 00:44:40,800 waves which i'll talk about in a minute 1242 00:44:44,550 --> 00:44:42,800 but we stop the computer simulation and 1243 00:44:46,470 --> 00:44:44,560 pause one last time 1244 00:44:48,390 --> 00:44:46,480 to show you a final pair of galaxies 1245 00:44:50,150 --> 00:44:48,400 that are very far along the atoms for 1246 00:44:52,630 --> 00:44:50,160 peace galaxy very far along 1247 00:44:54,150 --> 00:44:52,640 in the collision process so galaxy 1248 00:44:56,470 --> 00:44:54,160 collisions are common 1249 00:44:58,309 --> 00:44:56,480 they are spectacular as you can see here 1250 00:45:02,230 --> 00:44:58,319 both from computer simulations 1251 00:45:04,390 --> 00:45:02,240 and from actual 1252 00:45:05,910 --> 00:45:04,400 images of colliding galaxies and if 1253 00:45:09,030 --> 00:45:05,920 you're wondering you know 1254 00:45:11,829 --> 00:45:09,040 that's all good why do we care we care 1255 00:45:15,990 --> 00:45:14,470 the milky way and andromeda galaxies are 1256 00:45:18,150 --> 00:45:16,000 going to collide in the future 1257 00:45:19,670 --> 00:45:18,160 and i'm going to again remove the label 1258 00:45:22,069 --> 00:45:19,680 and show you a wonderful set of 1259 00:45:24,150 --> 00:45:22,079 simulations carried out by john dubinsky 1260 00:45:26,390 --> 00:45:24,160 and collaborators at the university of 1261 00:45:27,750 --> 00:45:26,400 toronto and the canadian institute for 1262 00:45:31,030 --> 00:45:27,760 theoretical astronomy 1263 00:45:32,230 --> 00:45:31,040 the future sky you know this is a image 1264 00:45:34,550 --> 00:45:32,240 of the milky way 1265 00:45:37,190 --> 00:45:34,560 that's viewed from the sun and there's 1266 00:45:38,950 --> 00:45:37,200 andromeda coming through 1267 00:45:41,030 --> 00:45:38,960 as we go forward in time so it's really 1268 00:45:44,550 --> 00:45:41,040 about the future sky and this is 1269 00:45:47,270 --> 00:45:44,560 um john dobinski and john camille farah 1270 00:45:48,390 --> 00:45:47,280 from you toronto and ceta who put this 1271 00:45:49,750 --> 00:45:48,400 together 1272 00:45:51,829 --> 00:45:49,760 look what happens to the andromeda 1273 00:45:54,790 --> 00:45:51,839 galaxy as it swings through 1274 00:45:55,430 --> 00:45:54,800 it comes close it in one of its close 1275 00:45:58,710 --> 00:45:55,440 passage 1276 00:46:01,510 --> 00:45:58,720 we slow down so that you can really see 1277 00:46:05,510 --> 00:46:01,520 how spectacular its disruption is you'll 1278 00:46:09,190 --> 00:46:08,790 it gets ripped apart from a frisbee 1279 00:46:13,910 --> 00:46:09,200 shape 1280 00:46:15,910 --> 00:46:13,920 doing the same thing to the milky way 1281 00:46:17,270 --> 00:46:15,920 and in fact the sun is plunging in and 1282 00:46:18,630 --> 00:46:17,280 out of the milky way because the sun has 1283 00:46:20,309 --> 00:46:18,640 been perturbed in its orbit 1284 00:46:22,790 --> 00:46:20,319 that's why it looks like now you see me 1285 00:46:24,390 --> 00:46:22,800 now you don't it's because the sun 1286 00:46:26,470 --> 00:46:24,400 has been perturbed into a highly 1287 00:46:27,109 --> 00:46:26,480 eccentric orbit from its nearly circular 1288 00:46:29,750 --> 00:46:27,119 orbit 1289 00:46:31,109 --> 00:46:29,760 and in good time in a few billion years 1290 00:46:34,630 --> 00:46:31,119 the two galaxies 1291 00:46:37,430 --> 00:46:34,640 merge to form one galaxy okay so this is 1292 00:46:38,950 --> 00:46:37,440 a perspective from the sun of this 1293 00:46:40,309 --> 00:46:38,960 wonderful simulation of the milky way 1294 00:46:43,589 --> 00:46:40,319 andromeda collision 1295 00:46:44,309 --> 00:46:43,599 now i have to say that our group at uc 1296 00:46:45,990 --> 00:46:44,319 santa cruz 1297 00:46:48,309 --> 00:46:46,000 worked closely with a group at the space 1298 00:46:51,510 --> 00:46:48,319 telescope led by roland van der marrell 1299 00:46:53,030 --> 00:46:51,520 and really in um 1300 00:46:56,309 --> 00:46:53,040 before we started our work with the 1301 00:46:57,910 --> 00:46:56,319 group at um at space telescope in 2005 1302 00:46:59,670 --> 00:46:57,920 our group at santa cruz working with a 1303 00:47:00,630 --> 00:46:59,680 group at university of virginia group at 1304 00:47:03,349 --> 00:47:00,640 ucla 1305 00:47:05,589 --> 00:47:03,359 we jointly discovered that the milk that 1306 00:47:06,390 --> 00:47:05,599 the andromeda galaxy is about five times 1307 00:47:08,630 --> 00:47:06,400 bigger than p 1308 00:47:11,030 --> 00:47:08,640 people had previously given it credit 1309 00:47:12,390 --> 00:47:11,040 for instead of being a hundred thousand 1310 00:47:14,870 --> 00:47:12,400 light years across 1311 00:47:15,910 --> 00:47:14,880 we found that the andromeda galaxy is at 1312 00:47:18,550 --> 00:47:15,920 least 1313 00:47:19,910 --> 00:47:18,560 500 000 light years across so imagine 1314 00:47:21,270 --> 00:47:19,920 this you know you wake up one morning 1315 00:47:22,470 --> 00:47:21,280 you find out you're five times bigger 1316 00:47:23,670 --> 00:47:22,480 than you previously thought 1317 00:47:25,750 --> 00:47:23,680 but you're going to bump into things 1318 00:47:28,630 --> 00:47:25,760 you're going to bump into things and 1319 00:47:29,430 --> 00:47:28,640 um so galaxy collisions become even more 1320 00:47:31,829 --> 00:47:29,440 of a 1321 00:47:33,829 --> 00:47:31,839 thing if uh if galaxies are bigger than 1322 00:47:36,630 --> 00:47:33,839 people previously thought 1323 00:47:38,390 --> 00:47:36,640 another discovery we made not in 2005 1324 00:47:40,470 --> 00:47:38,400 now but fast forward to 2012 1325 00:47:42,230 --> 00:47:40,480 seven years later working with a group 1326 00:47:42,790 --> 00:47:42,240 at space telescope led by roland van de 1327 00:47:45,030 --> 00:47:42,800 mero 1328 00:47:46,790 --> 00:47:45,040 and collaborators we discovered that not 1329 00:47:48,230 --> 00:47:46,800 only is the andromeda galaxy much bigger 1330 00:47:51,430 --> 00:47:48,240 than we previously thought 1331 00:47:52,150 --> 00:47:51,440 it's heading straight for us you know as 1332 00:47:56,390 --> 00:47:52,160 the 1333 00:47:57,750 --> 00:47:56,400 joke goes people wondered why andromeda 1334 00:47:59,990 --> 00:47:57,760 was getting bigger and bigger and then 1335 00:48:00,950 --> 00:48:00,000 it hit us um and robert is heading 1336 00:48:03,990 --> 00:48:00,960 straight for us 1337 00:48:06,309 --> 00:48:04,000 and uh in with that discovery uh 1338 00:48:08,390 --> 00:48:06,319 came a nasa press release where they put 1339 00:48:09,589 --> 00:48:08,400 this video together the future milky way 1340 00:48:11,270 --> 00:48:09,599 andromeda 1341 00:48:12,870 --> 00:48:11,280 galactic collision again here's the 1342 00:48:13,349 --> 00:48:12,880 milky way the band of light of the milky 1343 00:48:14,950 --> 00:48:13,359 way 1344 00:48:16,390 --> 00:48:14,960 andromeda two and a half million light 1345 00:48:17,349 --> 00:48:16,400 years away and let's look at what our 1346 00:48:20,309 --> 00:48:17,359 future holds 1347 00:48:21,990 --> 00:48:20,319 i'll play this movie for you what our 1348 00:48:23,589 --> 00:48:22,000 movie holds is a much bigger andromeda 1349 00:48:24,870 --> 00:48:23,599 galaxy as it approaches us in two 1350 00:48:27,990 --> 00:48:24,880 billion years 1351 00:48:31,910 --> 00:48:28,000 galaxies 1352 00:48:33,589 --> 00:48:31,920 collide and soon there's such a 1353 00:48:37,030 --> 00:48:33,599 spectacular collision 1354 00:48:38,630 --> 00:48:37,040 that there are fireworks in the sky and 1355 00:48:40,309 --> 00:48:38,640 you know i'm fairly sure we've stopped 1356 00:48:41,670 --> 00:48:40,319 celebrating the fourth of july because 1357 00:48:42,150 --> 00:48:41,680 we'll have permanent fireworks in the 1358 00:48:43,670 --> 00:48:42,160 sky 1359 00:48:45,270 --> 00:48:43,680 and in seven billion years the two 1360 00:48:48,309 --> 00:48:45,280 galaxies have completely 1361 00:48:50,069 --> 00:48:48,319 merged to form one galaxy where there 1362 00:48:52,150 --> 00:48:50,079 used to be two the one galaxy that's 1363 00:48:53,349 --> 00:48:52,160 going to be called milkometer milky way 1364 00:48:55,670 --> 00:48:53,359 andromeda 1365 00:48:57,109 --> 00:48:55,680 now uh what is amazing is in seven 1366 00:48:58,950 --> 00:48:57,119 billion years 1367 00:49:00,950 --> 00:48:58,960 whatever these rocks are made of in the 1368 00:49:01,270 --> 00:49:00,960 foreground hillside haven't weathered it 1369 00:49:03,670 --> 00:49:01,280 for 1370 00:49:04,790 --> 00:49:03,680 in seven billion years so you know get a 1371 00:49:06,069 --> 00:49:04,800 hold of these rocks they're they're 1372 00:49:07,589 --> 00:49:06,079 wonderful things 1373 00:49:09,829 --> 00:49:07,599 um that's the one piece of the 1374 00:49:11,990 --> 00:49:09,839 simulation that i guess went a little 1375 00:49:13,750 --> 00:49:12,000 wrong now of course a lot is going to 1376 00:49:15,349 --> 00:49:13,760 happen in seven billion years so that's 1377 00:49:16,950 --> 00:49:15,359 a lot's gonna happen and much less than 1378 00:49:19,750 --> 00:49:16,960 that you know this pandemic is a 1379 00:49:21,910 --> 00:49:19,760 reminder of the fragility of human life 1380 00:49:23,190 --> 00:49:21,920 fragility of human life in the face of 1381 00:49:25,990 --> 00:49:23,200 disease you know 1382 00:49:26,630 --> 00:49:26,000 diseases caused by viruses degenerative 1383 00:49:33,349 --> 00:49:26,640 diseases 1384 00:49:35,270 --> 00:49:33,359 war and violence here on earth sadly uh 1385 00:49:36,710 --> 00:49:35,280 that's another thing we have to overcome 1386 00:49:39,270 --> 00:49:36,720 you know that's on time scales that are 1387 00:49:41,990 --> 00:49:39,280 much less than seven billion years 1388 00:49:42,870 --> 00:49:42,000 like disease we have to there's old age 1389 00:49:46,390 --> 00:49:42,880 you know 1390 00:49:48,710 --> 00:49:46,400 that we have to understand and conquer 1391 00:49:49,750 --> 00:49:48,720 um these are things that we really have 1392 00:49:51,349 --> 00:49:49,760 to get past 1393 00:49:53,270 --> 00:49:51,359 if we have to live long enough to 1394 00:49:56,150 --> 00:49:53,280 understand the future and 1395 00:49:56,870 --> 00:49:56,160 not understand witness the future 1396 00:49:57,910 --> 00:49:56,880 collision 1397 00:49:59,670 --> 00:49:57,920 there's another thing that's going to 1398 00:50:01,510 --> 00:49:59,680 happen which is the sun is going to 1399 00:50:03,829 --> 00:50:01,520 bloat up into a 1400 00:50:05,910 --> 00:50:03,839 a very large star we're going to become 1401 00:50:08,630 --> 00:50:05,920 a red giant engulf the earth 1402 00:50:09,270 --> 00:50:08,640 so we not only have to survive all these 1403 00:50:11,270 --> 00:50:09,280 things 1404 00:50:12,870 --> 00:50:11,280 we actually have to travel outwards in 1405 00:50:14,630 --> 00:50:12,880 the solar system 1406 00:50:16,069 --> 00:50:14,640 mars is probably too close we have to 1407 00:50:18,470 --> 00:50:16,079 get to one of the moons of the 1408 00:50:20,069 --> 00:50:18,480 gas giants you know saturn or jupiter 1409 00:50:21,670 --> 00:50:20,079 and watch this wonderful milky way 1410 00:50:23,670 --> 00:50:21,680 andromeda collision 1411 00:50:25,670 --> 00:50:23,680 um so that you know we can only watch it 1412 00:50:25,990 --> 00:50:25,680 if we can watch the sun bloat up from a 1413 00:50:29,109 --> 00:50:26,000 safe 1414 00:50:30,950 --> 00:50:29,119 distance and then outlive that and 1415 00:50:32,630 --> 00:50:30,960 watch the milky way andromeda collision 1416 00:50:34,870 --> 00:50:32,640 seven billion years from now so a lot to 1417 00:50:36,790 --> 00:50:34,880 think about for the future 1418 00:50:38,150 --> 00:50:36,800 okay um i do want to take you on a 1419 00:50:38,790 --> 00:50:38,160 little journey through the milky way to 1420 00:50:40,710 --> 00:50:38,800 get your 1421 00:50:42,230 --> 00:50:40,720 give you a sense of what space around us 1422 00:50:43,829 --> 00:50:42,240 looks like i'm still talking about 1423 00:50:45,430 --> 00:50:43,839 galaxies and their structure 1424 00:50:47,109 --> 00:50:45,440 this is a wonderful video that brent 1425 00:50:48,390 --> 00:50:47,119 tully uh my 1426 00:50:50,390 --> 00:50:48,400 astronomer colleague at the university 1427 00:50:51,349 --> 00:50:50,400 of hawaii and his and his collaborators 1428 00:50:52,950 --> 00:50:51,359 put together 1429 00:50:54,710 --> 00:50:52,960 this is flying through the milky way 1430 00:50:56,230 --> 00:50:54,720 into intergalactic space 1431 00:50:58,710 --> 00:50:56,240 i'm going to remove the label and if you 1432 00:50:59,829 --> 00:50:58,720 see this the orion nebula the three 1433 00:51:02,069 --> 00:50:59,839 stars 1434 00:51:03,990 --> 00:51:02,079 the sword of orion the other star some 1435 00:51:04,790 --> 00:51:04,000 of the other stars in iran the shoulders 1436 00:51:06,790 --> 00:51:04,800 etc 1437 00:51:08,790 --> 00:51:06,800 and as we zoom in you'll see that orion 1438 00:51:09,750 --> 00:51:08,800 is the stars in orion are not really at 1439 00:51:11,510 --> 00:51:09,760 one distance from us 1440 00:51:13,270 --> 00:51:11,520 as we zoom in towards it the 1441 00:51:15,510 --> 00:51:13,280 constellation loses its shape 1442 00:51:18,230 --> 00:51:15,520 you can see that the sword of orion is 1443 00:51:20,069 --> 00:51:18,240 not really one star it's a nebulae 1444 00:51:22,150 --> 00:51:20,079 it's a nebula of gas and dust out of 1445 00:51:23,589 --> 00:51:22,160 which new stars are born 1446 00:51:25,430 --> 00:51:23,599 you can see the band of light in the 1447 00:51:26,950 --> 00:51:25,440 milky way this wonderful video was put 1448 00:51:29,430 --> 00:51:26,960 together by taking actual 1449 00:51:31,349 --> 00:51:29,440 images astronomical images but putting 1450 00:51:33,270 --> 00:51:31,359 them at appropriate distances and then 1451 00:51:33,910 --> 00:51:33,280 taking this virtual journey through them 1452 00:51:37,270 --> 00:51:33,920 there's the 1453 00:51:39,109 --> 00:51:37,280 horsehead nebula and orion and 1454 00:51:40,470 --> 00:51:39,119 you know this is the milky way we're 1455 00:51:41,589 --> 00:51:40,480 going to go through an exploded star 1456 00:51:44,390 --> 00:51:41,599 this is this 1457 00:51:46,069 --> 00:51:44,400 pink pinkish white blob that's uh 1458 00:51:48,870 --> 00:51:46,079 getting bigger and bigger and 1459 00:51:50,309 --> 00:51:48,880 coming to the center of our screen 1460 00:51:52,950 --> 00:51:50,319 that's an exploded star 1461 00:51:55,349 --> 00:51:52,960 in our own galaxy we're going to go 1462 00:51:58,470 --> 00:51:55,359 through that 1463 00:51:59,030 --> 00:51:58,480 and as we do this we get to say get a 1464 00:52:01,030 --> 00:51:59,040 sense 1465 00:52:03,349 --> 00:52:01,040 of the structure of our own milky way 1466 00:52:06,470 --> 00:52:03,359 galaxy so you're going to see an image 1467 00:52:09,510 --> 00:52:06,480 soon of our own 1468 00:52:11,270 --> 00:52:09,520 milky way galaxy taken from a great 1469 00:52:12,630 --> 00:52:11,280 height so you can see the frisbee and 1470 00:52:13,750 --> 00:52:12,640 the shape of the frisbee and you're 1471 00:52:15,670 --> 00:52:13,760 wondering you know 1472 00:52:17,910 --> 00:52:15,680 how did brent tully get such a long 1473 00:52:19,670 --> 00:52:17,920 selfie stick how did he manage to take 1474 00:52:20,470 --> 00:52:19,680 this picture of the milky way taken from 1475 00:52:23,030 --> 00:52:20,480 the outside 1476 00:52:24,549 --> 00:52:23,040 you know this view right here where the 1477 00:52:26,230 --> 00:52:24,559 milky way 1478 00:52:28,630 --> 00:52:26,240 clearly looks like a frisbee because we 1479 00:52:30,790 --> 00:52:28,640 are so far away from it now that we can 1480 00:52:31,750 --> 00:52:30,800 get that perspective and the answer is 1481 00:52:34,390 --> 00:52:31,760 simple 1482 00:52:35,990 --> 00:52:34,400 brent has another galaxy playing the 1483 00:52:37,349 --> 00:52:36,000 role of the milky way this is not really 1484 00:52:40,630 --> 00:52:37,359 an image of the milky way it's an 1485 00:52:41,190 --> 00:52:40,640 actor playing the milky way on in this 1486 00:52:42,870 --> 00:52:41,200 video 1487 00:52:44,549 --> 00:52:42,880 now those two galaxies that came by 1488 00:52:46,230 --> 00:52:44,559 those other two galaxies that came by 1489 00:52:47,750 --> 00:52:46,240 those are real images of those companion 1490 00:52:49,430 --> 00:52:47,760 galaxies of the milky way 1491 00:52:50,950 --> 00:52:49,440 um you know in a second you'll see 1492 00:52:53,430 --> 00:52:50,960 andromeda coming in from the 1493 00:52:56,230 --> 00:52:53,440 uh upper right there's andromeda and its 1494 00:52:57,430 --> 00:52:56,240 companion there's the triangulum galaxy 1495 00:52:59,030 --> 00:52:57,440 we're going to go through an exploded 1496 00:53:00,549 --> 00:52:59,040 star and triangulum so you can see that 1497 00:53:02,950 --> 00:53:00,559 the milky way and 1498 00:53:04,390 --> 00:53:02,960 you know lives near other galaxies uh 1499 00:53:06,309 --> 00:53:04,400 each of these galaxies 1500 00:53:08,069 --> 00:53:06,319 you know if there are some that are 1501 00:53:09,030 --> 00:53:08,079 bigger than the milky way andromeda is 1502 00:53:10,710 --> 00:53:09,040 somewhat bigger 1503 00:53:12,470 --> 00:53:10,720 some are smaller triangulum is smaller 1504 00:53:14,950 --> 00:53:12,480 than the milky way you know 1505 00:53:16,309 --> 00:53:14,960 but you know 100 000 500 000 light years 1506 00:53:18,309 --> 00:53:16,319 across is quite typical 1507 00:53:21,030 --> 00:53:18,319 even for these tiny little specks in the 1508 00:53:23,190 --> 00:53:21,040 distance each of those is a galaxy 1509 00:53:24,390 --> 00:53:23,200 each of those has lots of stars and i 1510 00:53:26,150 --> 00:53:24,400 you know should have said this but the 1511 00:53:29,349 --> 00:53:26,160 milky way galaxy has about a 1512 00:53:32,390 --> 00:53:29,359 hundred billion stars you know one with 1513 00:53:33,910 --> 00:53:32,400 11 zeros after it but if that isn't bad 1514 00:53:35,910 --> 00:53:33,920 enough it contains 1515 00:53:37,750 --> 00:53:35,920 more dark matter more mass in the form 1516 00:53:39,430 --> 00:53:37,760 of dark matter than it does in stars 1517 00:53:40,470 --> 00:53:39,440 almost 10 times as much mass in dark 1518 00:53:42,790 --> 00:53:40,480 matter than it does 1519 00:53:44,390 --> 00:53:42,800 in stars and you know as you're seeing 1520 00:53:45,910 --> 00:53:44,400 this you're seeing a collection of 1521 00:53:47,349 --> 00:53:45,920 galaxies in the distance that's the 1522 00:53:48,790 --> 00:53:47,359 virgo cluster of galaxy 1523 00:53:50,390 --> 00:53:48,800 this is something that my colleagues and 1524 00:53:51,109 --> 00:53:50,400 my students and i are studying in great 1525 00:53:54,069 --> 00:53:51,119 detail 1526 00:53:56,790 --> 00:53:54,079 and there's a particularly monstrous 1527 00:53:58,390 --> 00:53:56,800 monstrous in terms of size uh galaxy at 1528 00:54:00,390 --> 00:53:58,400 the center of the virgo cluster that's a 1529 00:54:02,630 --> 00:54:00,400 result of many galactic collisions 1530 00:54:04,230 --> 00:54:02,640 and that's the messier 87 galaxy we're 1531 00:54:06,630 --> 00:54:04,240 going to crash land 1532 00:54:09,510 --> 00:54:06,640 into that galaxy to end this piece of 1533 00:54:12,230 --> 00:54:09,520 our virtual journey there's messier 1534 00:54:13,510 --> 00:54:12,240 m87 messier 87 that's a super massive 1535 00:54:15,670 --> 00:54:13,520 black hole at its center 1536 00:54:17,270 --> 00:54:15,680 a few billion solar masses and its 1537 00:54:20,390 --> 00:54:17,280 gravity has gathered 1538 00:54:22,630 --> 00:54:20,400 light around it stars around it sorry 1539 00:54:24,630 --> 00:54:22,640 that's what that brightening is and if 1540 00:54:26,470 --> 00:54:24,640 you look closely you'll see this bluish 1541 00:54:28,549 --> 00:54:26,480 white jet off to the left 1542 00:54:30,150 --> 00:54:28,559 um this we think this jet is from 1543 00:54:32,069 --> 00:54:30,160 material that's swirling around the 1544 00:54:33,990 --> 00:54:32,079 black hole and it's being squirted out 1545 00:54:35,270 --> 00:54:34,000 i'll show you that in the next animation 1546 00:54:38,309 --> 00:54:35,280 this is that same 1547 00:54:39,589 --> 00:54:38,319 same messier 87 galaxy 1548 00:54:41,829 --> 00:54:39,599 this time we're going to zoom into the 1549 00:54:44,230 --> 00:54:41,839 super massive black hole near the center 1550 00:54:45,670 --> 00:54:44,240 and because telescopes most telescopes 1551 00:54:46,630 --> 00:54:45,680 don't have the resolution to show that 1552 00:54:48,150 --> 00:54:46,640 kind of detail 1553 00:54:50,470 --> 00:54:48,160 we're going to resort to sort of an 1554 00:54:52,870 --> 00:54:50,480 artist's rendering of what's going on 1555 00:54:53,990 --> 00:54:52,880 at the center so we're going to zoom in 1556 00:54:57,109 --> 00:54:54,000 these little blobs 1557 00:54:59,750 --> 00:54:57,119 around our star clusters uh that are 1558 00:55:01,349 --> 00:54:59,760 orbiting m87 but as we zoom in as i said 1559 00:55:02,069 --> 00:55:01,359 you know this particular telescope loses 1560 00:55:04,230 --> 00:55:02,079 resolution 1561 00:55:05,750 --> 00:55:04,240 so we're sort of relying on an artist's 1562 00:55:06,470 --> 00:55:05,760 rendering of what's going on near the 1563 00:55:09,670 --> 00:55:06,480 center 1564 00:55:11,829 --> 00:55:09,680 believe is a supermassive black hole 1565 00:55:12,630 --> 00:55:11,839 with swirling material that's heated up 1566 00:55:17,190 --> 00:55:12,640 by the 1567 00:55:19,750 --> 00:55:17,200 and that's squirting out this 1568 00:55:21,670 --> 00:55:19,760 jet that you see going off like that now 1569 00:55:24,150 --> 00:55:21,680 this supermassive black hole 1570 00:55:26,630 --> 00:55:24,160 this very supermassive black hole at the 1571 00:55:29,270 --> 00:55:26,640 center of m87 was recently 1572 00:55:31,030 --> 00:55:29,280 the subject of a portrait a bunch of 1573 00:55:31,750 --> 00:55:31,040 radio telescopes got together and 1574 00:55:34,150 --> 00:55:31,760 decided 1575 00:55:35,589 --> 00:55:34,160 we would take a picture of this 1576 00:55:37,270 --> 00:55:35,599 supermassive black hole this happened 1577 00:55:39,670 --> 00:55:37,280 about two years ago 1578 00:55:42,069 --> 00:55:39,680 this is in a way it's an image of the 1579 00:55:44,309 --> 00:55:42,079 black hole but it's really a silhouette 1580 00:55:45,670 --> 00:55:44,319 of the black hole what happens is radio 1581 00:55:48,470 --> 00:55:45,680 waves that are 1582 00:55:49,510 --> 00:55:48,480 emanating from behind the black hole 1583 00:55:51,910 --> 00:55:49,520 beyond the black hole 1584 00:55:52,950 --> 00:55:51,920 they're getting bent by the gravity of 1585 00:55:55,270 --> 00:55:52,960 the black hole 1586 00:55:56,549 --> 00:55:55,280 all around to produce this ring this 1587 00:55:59,430 --> 00:55:56,559 partial einstein ring 1588 00:56:01,030 --> 00:55:59,440 this was this image was wonderful it was 1589 00:56:03,670 --> 00:56:01,040 really the first 1590 00:56:04,549 --> 00:56:03,680 real image of a black hole imaged with 1591 00:56:07,030 --> 00:56:04,559 the so-called 1592 00:56:08,470 --> 00:56:07,040 event horizon telescope it's not a 1593 00:56:10,549 --> 00:56:08,480 single telescope it's actually an 1594 00:56:12,150 --> 00:56:10,559 array of telescopes the largest array of 1595 00:56:13,829 --> 00:56:12,160 radio telescopes on earth 1596 00:56:15,990 --> 00:56:13,839 i can safely say that because these 1597 00:56:17,750 --> 00:56:16,000 telescopes are all over the earth so 1598 00:56:19,910 --> 00:56:17,760 you can have larger telescope arrays but 1599 00:56:21,910 --> 00:56:19,920 they wouldn't be earthbound anymore 1600 00:56:23,430 --> 00:56:21,920 anyway this wonderful image was taken 1601 00:56:26,789 --> 00:56:23,440 with this telescope 1602 00:56:28,230 --> 00:56:26,799 now the bending of light by gravity 1603 00:56:30,069 --> 00:56:28,240 of the black hole is what you're seeing 1604 00:56:32,470 --> 00:56:30,079 here light is bending around 1605 00:56:33,910 --> 00:56:32,480 the black hole to produce this apparent 1606 00:56:35,589 --> 00:56:33,920 ring 1607 00:56:37,190 --> 00:56:35,599 light can be bent by gravity in even 1608 00:56:39,270 --> 00:56:37,200 more spectacular ways 1609 00:56:40,630 --> 00:56:39,280 here's the light of distant galaxies 1610 00:56:43,589 --> 00:56:40,640 being bent 1611 00:56:45,349 --> 00:56:43,599 by the gravity of these two yellowish 1612 00:56:48,230 --> 00:56:45,359 white galaxies there these are 1613 00:56:49,270 --> 00:56:48,240 two galaxies in a cluster and they're 1614 00:56:51,109 --> 00:56:49,280 bending the light 1615 00:56:53,030 --> 00:56:51,119 of these background bluish white 1616 00:56:53,750 --> 00:56:53,040 galaxies you see the smile of the smiley 1617 00:57:02,150 --> 00:56:53,760 face 1618 00:57:02,950 --> 00:57:02,160 this gravitational light bending of 1619 00:57:04,789 --> 00:57:02,960 course 1620 00:57:06,870 --> 00:57:04,799 was a prediction of einstein's general 1621 00:57:08,789 --> 00:57:06,880 relativity and what i'm going to do at 1622 00:57:09,910 --> 00:57:08,799 this point in my talk is make a brief 1623 00:57:11,829 --> 00:57:09,920 pause 1624 00:57:13,589 --> 00:57:11,839 to reflect on something i've been 1625 00:57:14,870 --> 00:57:13,599 talking about the grandeur of the 1626 00:57:17,910 --> 00:57:14,880 universe 1627 00:57:21,510 --> 00:57:17,920 about the study of 1628 00:57:24,950 --> 00:57:21,520 universe cosmology astronomy space 1629 00:57:25,990 --> 00:57:24,960 stars galaxies and i would say i've 1630 00:57:27,510 --> 00:57:26,000 already talked about 1631 00:57:29,030 --> 00:57:27,520 the privilege of using the keck 1632 00:57:31,829 --> 00:57:29,040 telescope on mauna kea 1633 00:57:33,990 --> 00:57:31,839 i say it's a privilege to be paid a 1634 00:57:35,589 --> 00:57:34,000 salary to go off and study something as 1635 00:57:37,430 --> 00:57:35,599 beautiful as the universe 1636 00:57:38,789 --> 00:57:37,440 i feel completely privileged utterly 1637 00:57:41,750 --> 00:57:38,799 privileged to do that 1638 00:57:43,670 --> 00:57:41,760 and it's easy to look back over my 35 1639 00:57:45,430 --> 00:57:43,680 years of being an astronomer 1640 00:57:47,430 --> 00:57:45,440 and say that the most wonderful thing 1641 00:57:48,950 --> 00:57:47,440 about my career was getting to study 1642 00:57:51,030 --> 00:57:48,960 these wonderful 1643 00:57:52,630 --> 00:57:51,040 aspects these grand questions in the 1644 00:57:53,910 --> 00:57:52,640 universe some of the biggest questions 1645 00:57:55,349 --> 00:57:53,920 literally some of the biggest questions 1646 00:57:57,670 --> 00:57:55,359 humanity can ask 1647 00:57:59,670 --> 00:57:57,680 but as i look back it's really not the 1648 00:58:00,630 --> 00:57:59,680 grand questions that stick out the most 1649 00:58:03,990 --> 00:58:00,640 in my mind 1650 00:58:05,510 --> 00:58:04,000 it's the amazing people individuals 1651 00:58:08,710 --> 00:58:05,520 human beings 1652 00:58:10,230 --> 00:58:08,720 whose own stories have touched my own 1653 00:58:12,150 --> 00:58:10,240 and i want to spend a few minutes 1654 00:58:14,710 --> 00:58:12,160 acknowledging them because i wouldn't be 1655 00:58:17,510 --> 00:58:14,720 here without them 1656 00:58:19,270 --> 00:58:17,520 i want to acknowledge the person whose 1657 00:58:20,870 --> 00:58:19,280 theory predicted that light should be 1658 00:58:22,710 --> 00:58:20,880 bent by gravity and that's 1659 00:58:25,349 --> 00:58:22,720 albert einstein you see him on the left 1660 00:58:27,190 --> 00:58:25,359 there it's a photograph taken in 1912 1661 00:58:29,510 --> 00:58:27,200 around the time general relativity had 1662 00:58:31,190 --> 00:58:29,520 just been published and was very famous 1663 00:58:33,589 --> 00:58:31,200 as a theory that predicted that light 1664 00:58:37,270 --> 00:58:33,599 should be bent by gravity 1665 00:58:39,030 --> 00:58:37,280 1912 was also the year 1666 00:58:40,150 --> 00:58:39,040 when albert einstein's one of his 1667 00:58:41,349 --> 00:58:40,160 closest collaborators called 1668 00:58:41,990 --> 00:58:41,359 schwarzschild who you see with the 1669 00:58:44,470 --> 00:58:42,000 impressive 1670 00:58:46,150 --> 00:58:44,480 facial hair in the upper right couch 1671 00:58:47,910 --> 00:58:46,160 schwarzschild was the first person to 1672 00:58:50,470 --> 00:58:47,920 solve einstein's equations of general 1673 00:58:52,230 --> 00:58:50,480 relativity in exact form so carl is 1674 00:58:53,510 --> 00:58:52,240 shown here in this picture because he 1675 00:58:55,270 --> 00:58:53,520 gave 1676 00:58:57,030 --> 00:58:55,280 rise to the notion that if you have a 1677 00:58:59,190 --> 00:58:57,040 point mass and you solve einstein's 1678 00:59:01,349 --> 00:58:59,200 equations of general relativity 1679 00:59:02,789 --> 00:59:01,359 you can get the notion of a black hole 1680 00:59:05,190 --> 00:59:02,799 okay so 1681 00:59:06,470 --> 00:59:05,200 called schwarzschild's name is attached 1682 00:59:08,470 --> 00:59:06,480 to the event horizon of a black hole 1683 00:59:10,710 --> 00:59:08,480 it's called the schwarzschild radius 1684 00:59:13,030 --> 00:59:10,720 but the short shield had an important 1685 00:59:14,470 --> 00:59:13,040 year in 1912 because their son martin 1686 00:59:17,190 --> 00:59:14,480 was born that year this is a 1687 00:59:18,549 --> 00:59:17,200 photograph of martin schwarchel taken 1688 00:59:20,870 --> 00:59:18,559 you know when he was 1689 00:59:22,230 --> 00:59:20,880 a professor at princeton so martin 1690 00:59:24,230 --> 00:59:22,240 shortshield 1691 00:59:26,390 --> 00:59:24,240 uh lost his father very early couch 1692 00:59:29,510 --> 00:59:26,400 watching died when he was in his 1693 00:59:32,710 --> 00:59:29,520 early 30s he died during world war one 1694 00:59:35,430 --> 00:59:32,720 martin um um 1695 00:59:35,910 --> 00:59:35,440 was visited by albert einstein martin 1696 00:59:37,990 --> 00:59:35,920 and his 1697 00:59:39,349 --> 00:59:38,000 family his mom uh they were visited by 1698 00:59:40,789 --> 00:59:39,359 albert einstein because 1699 00:59:42,309 --> 00:59:40,799 you know einstein had lost one of his 1700 00:59:44,069 --> 00:59:42,319 closest collaborators so martin 1701 00:59:47,190 --> 00:59:44,079 remembers albert einstein 1702 00:59:48,950 --> 00:59:47,200 uh when he was a child and martin came 1703 00:59:51,910 --> 00:59:48,960 to princeton university 1704 00:59:53,829 --> 00:59:51,920 the institute for advanced study they 1705 00:59:56,150 --> 00:59:53,839 reconnected in princeton 1706 00:59:57,910 --> 00:59:56,160 my connection to the soul pieces martin 1707 00:59:59,750 --> 00:59:57,920 schwartzel was an emeritus professor at 1708 01:00:00,630 --> 00:59:59,760 princeton university in the astrophysics 1709 01:00:02,549 --> 01:00:00,640 department 1710 01:00:04,069 --> 01:00:02,559 and he was one of my mentors when i went 1711 01:00:06,230 --> 01:00:04,079 to princeton 1712 01:00:07,589 --> 01:00:06,240 i got excellent advice about research 1713 01:00:09,109 --> 01:00:07,599 from him he was a mentor to many 1714 01:00:11,430 --> 01:00:09,119 students not just me 1715 01:00:13,430 --> 01:00:11,440 and so because he knew albert einstein 1716 01:00:15,510 --> 01:00:13,440 he is my one degree of separation from 1717 01:00:18,230 --> 01:00:15,520 albert einstein 1718 01:00:19,589 --> 01:00:18,240 as a student and later a postdoc at 1719 01:00:22,789 --> 01:00:19,599 princeton i met 1720 01:00:25,190 --> 01:00:22,799 freeman dyson john wheeler 1721 01:00:26,789 --> 01:00:25,200 and lyman spitzer i'm in with an 1722 01:00:28,230 --> 01:00:26,799 emeritus professor in our department all 1723 01:00:29,750 --> 01:00:28,240 four of them had met einstein new 1724 01:00:32,069 --> 01:00:29,760 einstein when he was 1725 01:00:33,829 --> 01:00:32,079 a professor at the institute for 1726 01:00:36,150 --> 01:00:33,839 advanced study so i have not one but 1727 01:00:38,390 --> 01:00:36,160 four one degrees of separation to albert 1728 01:00:41,829 --> 01:00:38,400 einstein thanks to martin 1729 01:00:43,750 --> 01:00:41,839 freeman john wheeler and lyman lyman 1730 01:00:46,950 --> 01:00:43,760 spitzer 1731 01:00:48,710 --> 01:00:46,960 now here's another person uh with whom i 1732 01:00:49,430 --> 01:00:48,720 feel one degree of separation stephen 1733 01:00:52,390 --> 01:00:49,440 hawking 1734 01:00:54,309 --> 01:00:52,400 whose excellent work explained how 1735 01:00:56,309 --> 01:00:54,319 radiation can actually 1736 01:00:57,910 --> 01:00:56,319 escape from a black hole not just a 1737 01:00:59,430 --> 01:00:57,920 one-way street things can escape from a 1738 01:01:01,270 --> 01:00:59,440 black hole hawking radiation 1739 01:01:02,710 --> 01:01:01,280 i had the privilege of going to one of 1740 01:01:04,069 --> 01:01:02,720 stephen hawking's talk right here in 1741 01:01:07,030 --> 01:01:04,079 santa clara where i live in 1742 01:01:08,390 --> 01:01:07,040 in santa clara county and california and 1743 01:01:10,470 --> 01:01:08,400 this connection was again through one 1744 01:01:11,270 --> 01:01:10,480 degree of separation my ucsc colleague 1745 01:01:13,750 --> 01:01:11,280 doug lynn 1746 01:01:14,630 --> 01:01:13,760 was a colleague of stephen hawkings in 1747 01:01:17,190 --> 01:01:14,640 cambridge 1748 01:01:19,430 --> 01:01:17,200 and doug got an invitation to stephen 1749 01:01:19,990 --> 01:01:19,440 hawking's talk so i got to listen to him 1750 01:01:21,589 --> 01:01:20,000 in person 1751 01:01:23,030 --> 01:01:21,599 we breathed in the same oxygen and 1752 01:01:27,510 --> 01:01:23,040 nitrogen breathed out the same 1753 01:01:29,589 --> 01:01:27,520 carbon dioxide in the same room um 1754 01:01:31,109 --> 01:01:29,599 there were people who touched me even 1755 01:01:36,870 --> 01:01:31,119 more 1756 01:01:37,990 --> 01:01:36,880 very reuben or the four i showed earlier 1757 01:01:41,030 --> 01:01:38,000 very ruben the discoverer 1758 01:01:43,349 --> 01:01:41,040 of dark matter and galaxies was actively 1759 01:01:45,510 --> 01:01:43,359 searching for dark matter in galaxies 1760 01:01:48,150 --> 01:01:45,520 when i was a starting graduate student 1761 01:01:49,589 --> 01:01:48,160 and she was an amazing mentor kind 1762 01:01:50,950 --> 01:01:49,599 gentle soul 1763 01:01:53,349 --> 01:01:50,960 i was a starting graduate student 1764 01:01:56,390 --> 01:01:53,359 studying the rotation curves of galaxies 1765 01:01:58,230 --> 01:01:56,400 in the virgo cluster and vera was really 1766 01:02:00,069 --> 01:01:58,240 kind took me under a wing and she was 1767 01:02:02,150 --> 01:02:00,079 she was doing her own studies but 1768 01:02:03,750 --> 01:02:02,160 uh really made me feel at home in in the 1769 01:02:05,990 --> 01:02:03,760 field of astronomy 1770 01:02:07,510 --> 01:02:06,000 uh subramanyam chandrasekhar imaged in 1771 01:02:10,630 --> 01:02:07,520 the middle he was a 1772 01:02:11,510 --> 01:02:10,640 famous famous astronomer who uh went 1773 01:02:14,549 --> 01:02:11,520 from india 1774 01:02:17,270 --> 01:02:14,559 to the uk first on his uh 1775 01:02:18,390 --> 01:02:17,280 voyage in the ship he worked out the 1776 01:02:20,069 --> 01:02:18,400 physics of 1777 01:02:21,910 --> 01:02:20,079 what later came to be known as neutron 1778 01:02:24,710 --> 01:02:21,920 stars um 1779 01:02:26,470 --> 01:02:24,720 went on to a illustrious career at the 1780 01:02:28,710 --> 01:02:26,480 university of chicago 1781 01:02:30,230 --> 01:02:28,720 illustrious beyond belief he had he got 1782 01:02:32,390 --> 01:02:30,240 the nobel prize 1783 01:02:34,549 --> 01:02:32,400 but even well before he got this nobel 1784 01:02:37,750 --> 01:02:34,559 prize he had phd students 1785 01:02:40,630 --> 01:02:37,760 in physics chemistry and mathematics 1786 01:02:43,270 --> 01:02:40,640 he was a polymath he was able to advise 1787 01:02:47,670 --> 01:02:43,280 phd thesis in all three subjects 1788 01:02:50,870 --> 01:02:47,680 one of his astronomy phds guido monk 1789 01:02:52,630 --> 01:02:50,880 went on to a faculty position at rice 1790 01:02:55,510 --> 01:02:52,640 university 1791 01:02:57,829 --> 01:02:55,520 guido had phd students at rice one of 1792 01:02:58,789 --> 01:02:57,839 his phd students very illustrious phd 1793 01:03:01,670 --> 01:02:58,799 student 1794 01:03:03,829 --> 01:03:01,680 jim gunn went on to become a professor 1795 01:03:08,069 --> 01:03:03,839 first at caltech then at princeton 1796 01:03:11,109 --> 01:03:08,079 and i was one of jim's phd students 1797 01:03:14,710 --> 01:03:11,119 so chandrasekhar is my great great 1798 01:03:15,430 --> 01:03:14,720 grand thesis advisor i had the privilege 1799 01:03:18,390 --> 01:03:15,440 of meeting him 1800 01:03:19,990 --> 01:03:18,400 in princeton i had lunch with him um 1801 01:03:20,870 --> 01:03:20,000 grad students and i had lunch with him 1802 01:03:23,430 --> 01:03:20,880 and again 1803 01:03:25,109 --> 01:03:23,440 it's these people whose journeys whose 1804 01:03:27,829 --> 01:03:25,119 amazing minds 1805 01:03:29,829 --> 01:03:27,839 um have left a bigger impression on me 1806 01:03:31,670 --> 01:03:29,839 than anything i've studied in astronomy 1807 01:03:32,549 --> 01:03:31,680 finally mother teresa this is an oil 1808 01:03:33,910 --> 01:03:32,559 painting that i 1809 01:03:35,750 --> 01:03:33,920 it's very close to my heart an oil 1810 01:03:38,870 --> 01:03:35,760 painting i did of mother teresa 1811 01:03:40,950 --> 01:03:38,880 in 2007 10 years after her death 1812 01:03:43,510 --> 01:03:40,960 she's someone i met for all of 10 1813 01:03:45,910 --> 01:03:43,520 seconds no words exchanged but 1814 01:03:46,549 --> 01:03:45,920 met her one one on one for about 10 1815 01:03:48,789 --> 01:03:46,559 seconds 1816 01:03:50,630 --> 01:03:48,799 in uh in one of her orphanages in 1817 01:03:53,829 --> 01:03:50,640 calcutta 1818 01:03:55,829 --> 01:03:53,839 so with this let me come back and close 1819 01:03:57,109 --> 01:03:55,839 up my science story 1820 01:03:59,109 --> 01:03:57,119 i've been talking about the darkest 1821 01:04:02,069 --> 01:03:59,119 secrets of the universe what one of the 1822 01:04:03,270 --> 01:04:02,079 universe's darkest secrets was sort of 1823 01:04:05,990 --> 01:04:03,280 reserved 1824 01:04:06,950 --> 01:04:06,000 held in suspension for us for the 1825 01:04:11,270 --> 01:04:06,960 longest time 1826 01:04:16,069 --> 01:04:11,280 it's only in 2015 that the first 1827 01:04:19,190 --> 01:04:16,079 detection of ripples of gravitation 1828 01:04:20,950 --> 01:04:19,200 through the universe 2015 a hundred 1829 01:04:23,190 --> 01:04:20,960 years after einstein predicted 1830 01:04:25,270 --> 01:04:23,200 gravitational waves in 1915 they were 1831 01:04:27,990 --> 01:04:25,280 finally detected why did it 1832 01:04:29,910 --> 01:04:28,000 take so long it took so long because it 1833 01:04:34,950 --> 01:04:29,920 takes 1834 01:04:38,829 --> 01:04:34,960 immense precision hard work 1835 01:04:41,510 --> 01:04:38,839 years of years of hard work 1836 01:04:43,589 --> 01:04:41,520 self-belief and 1837 01:04:44,950 --> 01:04:43,599 what i'm reminded of i'm a huge sports 1838 01:04:48,230 --> 01:04:44,960 fan what i'm reminded of 1839 01:04:53,670 --> 01:04:48,240 is this man over here precision 1840 01:04:56,870 --> 01:04:55,670 he is someone's this is steph curry he's 1841 01:04:59,510 --> 01:04:56,880 risen above 1842 01:05:01,109 --> 01:04:59,520 the sport he's risen about his team the 1843 01:05:03,270 --> 01:05:01,119 golden state warriors risen above the 1844 01:05:05,190 --> 01:05:03,280 sport of basketball 1845 01:05:06,309 --> 01:05:05,200 risen above sports altogether in the 1846 01:05:08,789 --> 01:05:06,319 same way 1847 01:05:10,630 --> 01:05:08,799 this discovery of gravitational waves 1848 01:05:12,470 --> 01:05:10,640 while it was part of science was bigger 1849 01:05:14,309 --> 01:05:12,480 than science itself 1850 01:05:16,069 --> 01:05:14,319 what i mean by that is people who never 1851 01:05:17,349 --> 01:05:16,079 pay attention to science or rarely pay 1852 01:05:20,230 --> 01:05:17,359 attention to science 1853 01:05:21,190 --> 01:05:20,240 got up and took notice of the universe's 1854 01:05:23,990 --> 01:05:21,200 vibrations 1855 01:05:24,549 --> 01:05:24,000 being heard by us dark secrets being 1856 01:05:27,670 --> 01:05:24,559 heard 1857 01:05:31,829 --> 01:05:27,680 not seen by humanity 1858 01:05:33,670 --> 01:05:31,839 it took very fancy apparatus like this 1859 01:05:35,270 --> 01:05:33,680 ligo the laser interferometric 1860 01:05:36,390 --> 01:05:35,280 gravitational observatory this is a 1861 01:05:39,029 --> 01:05:36,400 schematic 1862 01:05:41,670 --> 01:05:39,039 this is an aerial view i won't go into 1863 01:05:44,789 --> 01:05:41,680 the details of it except to say 1864 01:05:47,670 --> 01:05:44,799 this was the magic moment in 2015 1865 01:05:48,230 --> 01:05:47,680 where the first chirp gravitational 1866 01:05:50,069 --> 01:05:48,240 chirp 1867 01:05:53,190 --> 01:05:50,079 due to the merger of two black holes was 1868 01:05:55,910 --> 01:05:53,200 heard in the two bottom panels 1869 01:05:57,270 --> 01:05:55,920 are theoretical predictions and the two 1870 01:05:59,670 --> 01:05:57,280 upper panels 1871 01:06:00,950 --> 01:05:59,680 are the signals signals received in 1872 01:06:03,990 --> 01:06:00,960 hanford washington 1873 01:06:05,589 --> 01:06:04,000 and livingston louisiana received within 1874 01:06:07,670 --> 01:06:05,599 a short while of each other because it 1875 01:06:09,029 --> 01:06:07,680 was finite light travel time between the 1876 01:06:11,270 --> 01:06:09,039 two 1877 01:06:12,309 --> 01:06:11,280 locations and this really was the first 1878 01:06:15,349 --> 01:06:12,319 detection 1879 01:06:17,910 --> 01:06:15,359 of gravity waves and it's the first time 1880 01:06:19,670 --> 01:06:17,920 humanity was hearing not just seeing the 1881 01:06:22,789 --> 01:06:19,680 universe 1882 01:06:25,750 --> 01:06:22,799 it's an incredibly subtle 1883 01:06:27,589 --> 01:06:25,760 signal um the signal of this 1884 01:06:31,029 --> 01:06:27,599 gravitational 1885 01:06:34,230 --> 01:06:31,039 um oscillation you know the entire 1886 01:06:37,670 --> 01:06:34,240 four kilometer baseline its length 1887 01:06:40,950 --> 01:06:37,680 changed by an amount that's 100 1888 01:06:43,510 --> 01:06:40,960 the diameter of a proton 1889 01:06:44,870 --> 01:06:43,520 again the four kilometer baseline of the 1890 01:06:47,029 --> 01:06:44,880 ligo array 1891 01:06:49,510 --> 01:06:47,039 oscillated by with an amplitude that's 1892 01:06:50,549 --> 01:06:49,520 100 the diameter not of an atom but of a 1893 01:06:52,309 --> 01:06:50,559 proton 1894 01:06:54,230 --> 01:06:52,319 in other words the distance between us 1895 01:06:56,549 --> 01:06:54,240 and alpha centauri 1896 01:06:57,829 --> 01:06:56,559 oscillated by an amount that's the 1897 01:07:00,309 --> 01:06:57,839 breadth of human hair 1898 01:07:01,910 --> 01:07:00,319 it's an incredibly subtle measurement 1899 01:07:03,589 --> 01:07:01,920 it's remarkable to 1900 01:07:05,589 --> 01:07:03,599 the wonderful engineers and scientists 1901 01:07:09,349 --> 01:07:05,599 who made this possible 1902 01:07:11,029 --> 01:07:09,359 um in 2017 two years later you know 1903 01:07:12,870 --> 01:07:11,039 one of my colleagues at uc santa cruz 1904 01:07:13,990 --> 01:07:12,880 and indeed other astronomers around the 1905 01:07:16,470 --> 01:07:14,000 world 1906 01:07:18,069 --> 01:07:16,480 not only heard a chirp this time this 1907 01:07:20,230 --> 01:07:18,079 time it was a chirp due to two emerging 1908 01:07:21,109 --> 01:07:20,240 neutron stars the kind chandrasekhar had 1909 01:07:23,270 --> 01:07:21,119 studied 1910 01:07:24,549 --> 01:07:23,280 but they also saw the flash of light 1911 01:07:26,309 --> 01:07:24,559 they not only heard the chirp of the 1912 01:07:28,309 --> 01:07:26,319 bird they saw the proverbial bird fly 1913 01:07:30,630 --> 01:07:28,319 away so they were able to connect 1914 01:07:31,910 --> 01:07:30,640 the sense of hearing or sensing of 1915 01:07:33,990 --> 01:07:31,920 gravitational waves to 1916 01:07:35,270 --> 01:07:34,000 electromagnetic radiation another 1917 01:07:36,950 --> 01:07:35,280 miracle moment 1918 01:07:38,710 --> 01:07:36,960 now i've been talking about galaxies and 1919 01:07:41,990 --> 01:07:38,720 black holes a lot in this 1920 01:07:43,270 --> 01:07:42,000 very last segment of my talk i want to 1921 01:07:45,750 --> 01:07:43,280 leave you with 1922 01:07:47,430 --> 01:07:45,760 how galaxies came into being i hope i've 1923 01:07:49,510 --> 01:07:47,440 convinced you that you know we living 1924 01:07:51,190 --> 01:07:49,520 things rely on complex molecules 1925 01:07:53,510 --> 01:07:51,200 these complex molecules have to be 1926 01:07:55,910 --> 01:07:53,520 synthesized from stardust 1927 01:07:57,270 --> 01:07:55,920 stardust only happens if you're part of 1928 01:07:59,349 --> 01:07:57,280 a massive galaxy 1929 01:08:00,870 --> 01:07:59,359 so we owe our existence to the fact that 1930 01:08:02,710 --> 01:08:00,880 we live in a massive galaxy 1931 01:08:04,630 --> 01:08:02,720 but where did galaxies come from and the 1932 01:08:07,910 --> 01:08:04,640 answer will take us to the earliest 1933 01:08:09,589 --> 01:08:07,920 moments in the history of the universe 1934 01:08:11,910 --> 01:08:09,599 it'll actually take us back to something 1935 01:08:13,990 --> 01:08:11,920 called quantum fluctuations 1936 01:08:15,670 --> 01:08:14,000 in the early universe now if you're 1937 01:08:17,910 --> 01:08:15,680 wondering what quantum fluctuations 1938 01:08:19,510 --> 01:08:17,920 are don't worry i'm not about to give 1939 01:08:20,870 --> 01:08:19,520 you a lesson in quantum mechanics for 1940 01:08:21,430 --> 01:08:20,880 one thing i couldn't give you that 1941 01:08:22,870 --> 01:08:21,440 lesson 1942 01:08:24,789 --> 01:08:22,880 my knowledge of quantum mechanics isn't 1943 01:08:25,590 --> 01:08:24,799 good enough to do that but what i will 1944 01:08:28,550 --> 01:08:25,600 give you 1945 01:08:29,829 --> 01:08:28,560 is a description of an experiment called 1946 01:08:32,950 --> 01:08:29,839 the schrodinger's 1947 01:08:34,709 --> 01:08:32,960 cat experiment now this was a duncan 1948 01:08:37,189 --> 01:08:34,719 experiment a thought experiment that 1949 01:08:38,950 --> 01:08:37,199 schrolinger thought up he said you know 1950 01:08:40,789 --> 01:08:38,960 the quantum 1951 01:08:42,870 --> 01:08:40,799 uncertainty which was you know very 1952 01:08:44,470 --> 01:08:42,880 popular uh about 100 1953 01:08:46,070 --> 01:08:44,480 you know came into popularity a little 1954 01:08:47,349 --> 01:08:46,080 over 100 years ago 1955 01:08:50,550 --> 01:08:47,359 surely that was one of the drivers of 1956 01:08:53,910 --> 01:08:50,560 this heisenberg boar 1957 01:08:55,590 --> 01:08:53,920 they said you know the world of atoms 1958 01:08:57,749 --> 01:08:55,600 microscopic world of atoms is governed 1959 01:08:59,669 --> 01:08:57,759 by chance you know a probability 1960 01:09:02,070 --> 01:08:59,679 if you put radioactive material like you 1961 01:09:04,870 --> 01:09:02,080 see in this test tube here 1962 01:09:06,390 --> 01:09:04,880 there's a 50 chance that one alpha 1963 01:09:06,709 --> 01:09:06,400 particle will be emitted in the next 1964 01:09:09,349 --> 01:09:06,719 hour 1965 01:09:10,149 --> 01:09:09,359 50 chance so if you set it up in a box 1966 01:09:11,910 --> 01:09:10,159 like this 1967 01:09:13,269 --> 01:09:11,920 there's a 50 chance that an alpha 1968 01:09:15,430 --> 01:09:13,279 particle will go 1969 01:09:16,709 --> 01:09:15,440 and the geiger counter is set up so that 1970 01:09:18,070 --> 01:09:16,719 instead of beeping 1971 01:09:20,149 --> 01:09:18,080 there'll be a hammer that'll fall on a 1972 01:09:21,590 --> 01:09:20,159 bottle of cyanide that'll kill the poor 1973 01:09:25,910 --> 01:09:21,600 cat that you put in the box 1974 01:09:27,749 --> 01:09:25,920 but there's also a 50 chance that the 1975 01:09:29,590 --> 01:09:27,759 alpha particle won't be emitted the cat 1976 01:09:31,749 --> 01:09:29,600 will be alive so 1977 01:09:33,829 --> 01:09:31,759 this is a thought experiment saying that 1978 01:09:34,709 --> 01:09:33,839 if you set it up such that there's a 50 1979 01:09:36,550 --> 01:09:34,719 probability 1980 01:09:38,390 --> 01:09:36,560 and you set up say a thousand boxes with 1981 01:09:41,510 --> 01:09:38,400 a thousand each with a cat inside 1982 01:09:45,189 --> 01:09:41,520 you couldn't predict beforehand which 1983 01:09:47,269 --> 01:09:45,199 of these is going to be 1984 01:09:48,630 --> 01:09:47,279 the live cat box which of these are 1985 01:09:49,749 --> 01:09:48,640 going to be dead cat boxes which of 1986 01:09:51,829 --> 01:09:49,759 these are going to end up 1987 01:09:54,149 --> 01:09:51,839 like this versus like this you cannot 1988 01:09:57,270 --> 01:09:54,159 predict so the so the uncertainty 1989 01:10:00,390 --> 01:09:57,280 in the nature of quantum 1990 01:10:00,870 --> 01:10:00,400 physics translates to the macroscopic 1991 01:10:04,229 --> 01:10:00,880 world 1992 01:10:05,830 --> 01:10:04,239 of the cat and the cat's owner now 1993 01:10:07,590 --> 01:10:05,840 remember this experiment was a thought 1994 01:10:09,590 --> 01:10:07,600 experiment no animals were harmed in the 1995 01:10:11,830 --> 01:10:09,600 making of this experiment 1996 01:10:13,510 --> 01:10:11,840 however this experiment was never 1997 01:10:13,990 --> 01:10:13,520 carried out that's why no animals were 1998 01:10:15,830 --> 01:10:14,000 harmed 1999 01:10:17,350 --> 01:10:15,840 the universe went ahead and carried out 2000 01:10:19,430 --> 01:10:17,360 its own version 2001 01:10:21,110 --> 01:10:19,440 of the schrodinger cat experiment 2002 01:10:23,189 --> 01:10:21,120 shortly after the big bang there were 2003 01:10:24,630 --> 01:10:23,199 quantum fluctuations you see a timeline 2004 01:10:26,709 --> 01:10:24,640 of the universe on the x-axis 2005 01:10:28,390 --> 01:10:26,719 shortly after the big bang there were 2006 01:10:30,709 --> 01:10:28,400 quantum fluctuations 2007 01:10:32,790 --> 01:10:30,719 that got blown up just just like the 2008 01:10:34,790 --> 01:10:32,800 geiger counter takes the alpha particle 2009 01:10:36,390 --> 01:10:34,800 and creates a macroscopic signal 2010 01:10:37,990 --> 01:10:36,400 in the form of a beep or a falling 2011 01:10:39,669 --> 01:10:38,000 hammer the 2012 01:10:42,390 --> 01:10:39,679 inflation a very rapid period of 2013 01:10:45,430 --> 01:10:42,400 expansion shortly after the big bang 2014 01:10:47,830 --> 01:10:45,440 makes this transition from microscopic 2015 01:10:50,470 --> 01:10:47,840 quantum fluctuations to macroscopic 2016 01:10:52,870 --> 01:10:50,480 fluctuations in the fabric of space-time 2017 01:10:53,750 --> 01:10:52,880 gravity then takes over and makes the 2018 01:10:55,510 --> 01:10:53,760 rich richer 2019 01:10:57,990 --> 01:10:55,520 poor poorer over time to produce 2020 01:11:01,669 --> 01:10:58,000 galaxies the way that happens 2021 01:11:04,790 --> 01:11:01,679 is really over a long period of time 2022 01:11:05,510 --> 01:11:04,800 but this schrodinger scat experiment 2023 01:11:08,870 --> 01:11:05,520 that 2024 01:11:11,990 --> 01:11:08,880 is not hypothetical 2025 01:11:14,470 --> 01:11:12,000 we can now see the afterglow in the 2026 01:11:16,870 --> 01:11:14,480 afterglow of the big bang we can see the 2027 01:11:17,830 --> 01:11:16,880 imprint of these tiny quantum 2028 01:11:19,430 --> 01:11:17,840 fluctuations 2029 01:11:20,870 --> 01:11:19,440 and i'm going to play this movie so you 2030 01:11:22,870 --> 01:11:20,880 can see this 2031 01:11:24,070 --> 01:11:22,880 globe that you see this sphere that you 2032 01:11:27,110 --> 01:11:24,080 see spinning 2033 01:11:27,830 --> 01:11:27,120 is an actual map a radio map microwave 2034 01:11:29,910 --> 01:11:27,840 map 2035 01:11:30,950 --> 01:11:29,920 off the afterglow from the big bang and 2036 01:11:33,350 --> 01:11:30,960 you can see 2037 01:11:34,630 --> 01:11:33,360 that it's not uniformly um it's not 2038 01:11:35,830 --> 01:11:34,640 uniformly the same temperature there are 2039 01:11:39,350 --> 01:11:35,840 tiny fluctuations 2040 01:11:42,550 --> 01:11:39,360 it's these fluctuations that um 2041 01:11:45,030 --> 01:11:42,560 started out as the seeds of galaxies 2042 01:11:46,870 --> 01:11:45,040 gravity then took over you see the tiny 2043 01:11:49,669 --> 01:11:46,880 fluctuations early on 2044 01:11:50,070 --> 01:11:49,679 but gravity acts on them you'll see that 2045 01:11:53,189 --> 01:11:50,080 the 2046 01:11:53,990 --> 01:11:53,199 tiny up fluctuations get even richer and 2047 01:11:55,910 --> 01:11:54,000 richer over time 2048 01:11:57,430 --> 01:11:55,920 the tiny down fluctuations the parts 2049 01:12:00,070 --> 01:11:57,440 that were poorer than average 2050 01:12:00,630 --> 01:12:00,080 get completely emptied out and over a 2051 01:12:02,790 --> 01:12:00,640 period 2052 01:12:04,229 --> 01:12:02,800 of a long time over billions of years 2053 01:12:07,270 --> 01:12:04,239 you see time counting up 2054 01:12:09,270 --> 01:12:07,280 on the on the 2055 01:12:10,790 --> 01:12:09,280 upper right that's time in billions of 2056 01:12:12,070 --> 01:12:10,800 years giga years billions of years 2057 01:12:15,590 --> 01:12:12,080 that's a quarter of a billion 2058 01:12:19,590 --> 01:12:15,600 yes and the scale bar at the bottom 500 2059 01:12:22,709 --> 01:12:19,600 kiloparsecs that's about 2060 01:12:24,790 --> 01:12:22,719 one and a half million 2061 01:12:26,709 --> 01:12:24,800 light years that's what that scale bar 2062 01:12:28,229 --> 01:12:26,719 is so a little smaller than the under 2063 01:12:30,550 --> 01:12:28,239 about half the andromeda milky way 2064 01:12:32,709 --> 01:12:30,560 distance what you're seeing form here 2065 01:12:33,669 --> 01:12:32,719 is through the moderated gravity of dark 2066 01:12:37,110 --> 01:12:33,679 matter 2067 01:12:38,870 --> 01:12:37,120 collision you've seen the formation of a 2068 01:12:41,430 --> 01:12:38,880 galaxy like the milky way 2069 01:12:43,510 --> 01:12:41,440 so i know i'm i've been speaking for a 2070 01:12:44,310 --> 01:12:43,520 long time so let me wrap up my story by 2071 01:12:45,830 --> 01:12:44,320 saying 2072 01:12:47,990 --> 01:12:45,840 here's an image of the afterglow from 2073 01:12:50,550 --> 01:12:48,000 the big bang in it you can see 2074 01:12:51,189 --> 01:12:50,560 you know hot spots and cold spots the in 2075 01:12:58,310 --> 01:12:51,199 the 2076 01:13:01,590 --> 01:12:58,320 you can be sure 2077 01:13:02,790 --> 01:13:01,600 that this would have led to a an infant 2078 01:13:04,630 --> 01:13:02,800 galaxy 2079 01:13:07,350 --> 01:13:04,640 whose cannibalism over time would have 2080 01:13:09,669 --> 01:13:07,360 produced a massive galaxy 2081 01:13:11,990 --> 01:13:09,679 within which there were wonderful fields 2082 01:13:14,550 --> 01:13:12,000 of stars some of which exploded 2083 01:13:16,070 --> 01:13:14,560 and produced wonderful elements during 2084 01:13:17,110 --> 01:13:16,080 the lifetimes of these stars disperse 2085 01:13:20,229 --> 01:13:17,120 these elements 2086 01:13:22,550 --> 01:13:20,239 so that complex elements could get into 2087 01:13:23,510 --> 01:13:22,560 stars and planets next generation stars 2088 01:13:25,189 --> 01:13:23,520 and planets 2089 01:13:26,950 --> 01:13:25,199 on which there were complex molecules 2090 01:13:30,070 --> 01:13:26,960 and wonderful life forms 2091 01:13:31,110 --> 01:13:30,080 that's my daughter and son and thank you 2092 01:13:32,470 --> 01:13:31,120 ladies and gentlemen 2093 01:13:37,110 --> 01:13:32,480 um it's been a wonderful journey thank 2094 01:13:44,229 --> 01:13:40,630 all right thank you raja that was um 2095 01:13:46,470 --> 01:13:44,239 quite the tour of the universe 2096 01:13:48,550 --> 01:13:46,480 uh you there's there's there's barely a 2097 01:13:51,669 --> 01:13:48,560 scale you didn't touch in that 2098 01:13:54,149 --> 01:13:51,679 and uh i think it asked one of our um 2099 01:13:54,950 --> 01:13:54,159 we had a great audience on on youtube 2100 01:13:56,709 --> 01:13:54,960 and one of them 2101 01:13:58,950 --> 01:13:56,719 you know like you covered so many things 2102 01:13:59,510 --> 01:13:58,960 and it was like do you have a favorite 2103 01:14:02,310 --> 01:13:59,520 amongst 2104 01:14:02,950 --> 01:14:02,320 all of those variety of scales that you 2105 01:14:05,350 --> 01:14:02,960 covered or 2106 01:14:06,709 --> 01:14:05,360 favorite celestial body amongst all of 2107 01:14:07,669 --> 01:14:06,719 them they were it was one of the 2108 01:14:10,229 --> 01:14:07,679 questions 2109 01:14:11,510 --> 01:14:10,239 okay i'm going to maybe i'll stop 2110 01:14:12,229 --> 01:14:11,520 sharing my screen while i answer 2111 01:14:15,510 --> 01:14:12,239 questions 2112 01:14:17,110 --> 01:14:15,520 sure um i like to say that the andromeda 2113 01:14:18,790 --> 01:14:17,120 galaxy is my favorite galaxy in the 2114 01:14:20,229 --> 01:14:18,800 whole world and that's a joke of course 2115 01:14:22,470 --> 01:14:20,239 because it's not in the world 2116 01:14:23,430 --> 01:14:22,480 um but uh if i had to pick one favorite 2117 01:14:25,189 --> 01:14:23,440 thing 2118 01:14:27,510 --> 01:14:25,199 every time i see the andromeda galaxy it 2119 01:14:29,030 --> 01:14:27,520 feels like home that's right 2120 01:14:30,470 --> 01:14:29,040 was it was one of those lunches at the 2121 01:14:31,990 --> 01:14:30,480 institute for advanced study when you 2122 01:14:34,630 --> 01:14:32,000 unfurled the uh 2123 01:14:36,390 --> 01:14:34,640 six foot long poster it was a nine foot 2124 01:14:39,110 --> 01:14:36,400 a three foot by nine foot poster i still 2125 01:14:40,709 --> 01:14:39,120 have that in my office 2126 01:14:42,550 --> 01:14:40,719 i do remember that that was that was 2127 01:14:44,390 --> 01:14:42,560 quite the moment all right 2128 01:14:46,070 --> 01:14:44,400 so um i've been monitoring some of the 2129 01:14:47,910 --> 01:14:46,080 questions but grant justice has been 2130 01:14:50,070 --> 01:14:47,920 monitoring a little bit better than i am 2131 01:14:51,669 --> 01:14:50,080 so grant why don't you turn on your 2132 01:14:55,189 --> 01:14:51,679 video and join us and help 2133 01:14:57,430 --> 01:14:55,199 moderate the questions absolutely 2134 01:14:58,630 --> 01:14:57,440 thank you frank you've got your nasa 2135 01:15:01,910 --> 01:14:58,640 pajamas on today 2136 01:15:04,550 --> 01:15:01,920 i do yeah gotta bring back the old 2137 01:15:08,630 --> 01:15:07,430 all right so um yeah our chat has been 2138 01:15:11,430 --> 01:15:08,640 quite active 2139 01:15:13,030 --> 01:15:11,440 thank you for the phenomenal talk 2140 01:15:16,229 --> 01:15:13,040 everyone's been 2141 01:15:18,470 --> 01:15:16,239 as excited as we have been about this so 2142 01:15:19,910 --> 01:15:18,480 um frank already got the first question 2143 01:15:22,950 --> 01:15:19,920 that i wrote down because 2144 01:15:25,390 --> 01:15:22,960 grapevines think alike so um 2145 01:15:26,709 --> 01:15:25,400 another one is uh what will happen to 2146 01:15:31,830 --> 01:15:26,719 m33 2147 01:15:35,270 --> 01:15:33,910 that's a wonderful question wonderful 2148 01:15:36,790 --> 01:15:35,280 question and it's something we're 2149 01:15:40,630 --> 01:15:36,800 researching right now 2150 01:15:41,910 --> 01:15:40,640 um i won't have an answer for you for a 2151 01:15:43,030 --> 01:15:41,920 few more years 2152 01:15:44,790 --> 01:15:43,040 but one of the things we're trying to 2153 01:15:45,669 --> 01:15:44,800 measure right now with the hubble space 2154 01:15:47,030 --> 01:15:45,679 telescope 2155 01:15:48,870 --> 01:15:47,040 is we're trying to measure the lateral 2156 01:15:51,189 --> 01:15:48,880 motion of m33 2157 01:15:52,390 --> 01:15:51,199 you know we know it's line of sight 2158 01:15:55,669 --> 01:15:52,400 motion if you think of 2159 01:15:57,750 --> 01:15:55,679 x y and z as three axes if the plane of 2160 01:16:00,229 --> 01:15:57,760 the sky is x and y 2161 01:16:02,550 --> 01:16:00,239 we know the z component of n33 is motion 2162 01:16:03,830 --> 01:16:02,560 we know it's moving towards us at 180 2163 01:16:05,590 --> 01:16:03,840 kilometers per second it's moving 2164 01:16:06,950 --> 01:16:05,600 towards the sun at that speed 2165 01:16:08,709 --> 01:16:06,960 and ramadan is moving towards it's at 2166 01:16:12,630 --> 01:16:08,719 300 kilometers per second 2167 01:16:15,750 --> 01:16:12,640 uh so we can see that m33 2168 01:16:17,189 --> 01:16:15,760 is both further away than andromeda but 2169 01:16:19,110 --> 01:16:17,199 also coming towards us 2170 01:16:20,470 --> 01:16:19,120 more slowly than andromeda so they're 2171 01:16:22,470 --> 01:16:20,480 going to separate 2172 01:16:24,550 --> 01:16:22,480 in time what we don't know at all about 2173 01:16:27,590 --> 01:16:24,560 m33 is how fast it's moving in 2174 01:16:28,470 --> 01:16:27,600 x and y and that's something we're 2175 01:16:31,030 --> 01:16:28,480 trying to measure 2176 01:16:33,669 --> 01:16:31,040 right now with repeat measurements with 2177 01:16:35,189 --> 01:16:33,679 hubble it's like watching 2178 01:16:36,790 --> 01:16:35,199 if you take an image with hubble and you 2179 01:16:39,669 --> 01:16:36,800 take another image 10 years 2180 01:16:41,110 --> 01:16:39,679 later you can see a slight creep in the 2181 01:16:42,790 --> 01:16:41,120 stars relative to the background 2182 01:16:45,430 --> 01:16:42,800 wallpaper of distant galaxies 2183 01:16:46,550 --> 01:16:45,440 it's like watching an insect crawl very 2184 01:16:48,630 --> 01:16:46,560 slowly across 2185 01:16:49,990 --> 01:16:48,640 the wallpaper on your wall if you have 2186 01:16:51,910 --> 01:16:50,000 pattern wallpaper 2187 01:16:53,270 --> 01:16:51,920 you can see it if your wall is painted a 2188 01:16:54,870 --> 01:16:53,280 flat white it's very hard to see it 2189 01:16:56,790 --> 01:16:54,880 so we're using the background galaxies 2190 01:16:57,750 --> 01:16:56,800 that are behind frank right now in his 2191 01:16:59,990 --> 01:16:57,760 virtual screen 2192 01:17:01,590 --> 01:17:00,000 we're using those background galaxies as 2193 01:17:03,350 --> 01:17:01,600 the cosmic wallpaper against which to 2194 01:17:05,910 --> 01:17:03,360 measure the motion of 2195 01:17:07,350 --> 01:17:05,920 stars now it's a very subtle notion it's 2196 01:17:07,830 --> 01:17:07,360 like watching human hair grow on the 2197 01:17:10,550 --> 01:17:07,840 moon 2198 01:17:11,510 --> 01:17:10,560 that's that's how subtle it is but 2199 01:17:17,270 --> 01:17:11,520 measurable 2200 01:17:17,990 --> 01:17:17,280 i think was the 2012 press release we 2201 01:17:21,350 --> 01:17:18,000 did on 2202 01:17:22,070 --> 01:17:21,360 the milky way andromeda one um gertina 2203 01:17:24,790 --> 01:17:22,080 besla 2204 01:17:26,870 --> 01:17:24,800 uh and roland van demar did simulations 2205 01:17:28,070 --> 01:17:26,880 that they included m33 2206 01:17:30,390 --> 01:17:28,080 but you're telling me that they really 2207 01:17:32,390 --> 01:17:30,400 didn't have good um full spatial motion 2208 01:17:34,390 --> 01:17:32,400 for m33 at that time 2209 01:17:35,750 --> 01:17:34,400 because correct their simulations in 2210 01:17:38,709 --> 01:17:35,760 their suite of simulations 2211 01:17:39,990 --> 01:17:38,719 about 20 percent of the time m-33 became 2212 01:17:43,750 --> 01:17:40,000 part of the 2213 01:17:44,149 --> 01:17:43,760 resulting collision no that's exactly 2214 01:17:46,390 --> 01:17:44,159 right 2215 01:17:47,910 --> 01:17:46,400 um and uh you know those simulations 2216 01:17:51,590 --> 01:17:47,920 were fantastic uh 2217 01:17:55,030 --> 01:17:53,110 routine is part of the team that's 2218 01:17:56,950 --> 01:17:55,040 trying to measure the lateral motion of 2219 01:17:58,630 --> 01:17:56,960 m33 for exactly these reasons we can 2220 01:18:01,990 --> 01:17:58,640 print it down then 2221 01:18:04,470 --> 01:18:02,000 in addition to the milky way andromeda 2222 01:18:06,790 --> 01:18:04,480 collision there's also the question of 2223 01:18:08,149 --> 01:18:06,800 what has m33 been up to in the past you 2224 01:18:10,149 --> 01:18:08,159 know if you know which way it's going 2225 01:18:12,070 --> 01:18:10,159 now you can tell where it's come from 2226 01:18:13,830 --> 01:18:12,080 and where it's going to be in the future 2227 01:18:16,870 --> 01:18:13,840 so we want to understand a little bit 2228 01:18:19,110 --> 01:18:16,880 about um whether m33 has been 2229 01:18:20,709 --> 01:18:19,120 a good child or a bad child a good 2230 01:18:21,590 --> 01:18:20,719 galaxy or a bad galaxy in terms of what 2231 01:18:24,870 --> 01:18:21,600 neighborhood it's been 2232 01:18:25,990 --> 01:18:24,880 in in the past okay grant another 2233 01:18:27,910 --> 01:18:26,000 question 2234 01:18:29,510 --> 01:18:27,920 sure um i'll take just a second and 2235 01:18:31,030 --> 01:18:29,520 address this one because we always get 2236 01:18:32,390 --> 01:18:31,040 this every week in the chat about a 2237 01:18:35,110 --> 01:18:32,400 million times 2238 01:18:36,390 --> 01:18:35,120 we have a couple of public lectures on 2239 01:18:38,550 --> 01:18:36,400 dark matter 2240 01:18:41,270 --> 01:18:38,560 um i would suggest checking those out 2241 01:18:44,950 --> 01:18:41,280 through the playlist for public lectures 2242 01:18:46,790 --> 01:18:44,960 um we we know we have many questions and 2243 01:18:48,709 --> 01:18:46,800 many answers but we also do them every 2244 01:18:50,470 --> 01:18:48,719 week so i would recommend checking out 2245 01:18:51,990 --> 01:18:50,480 some of those previous programs for 2246 01:18:55,110 --> 01:18:52,000 those because we go into depth that we 2247 01:18:56,709 --> 01:18:55,120 won't be able to go into now 2248 01:18:58,470 --> 01:18:56,719 several questions on the nature of dark 2249 01:19:01,750 --> 01:18:58,480 matter and dark energy today 2250 01:19:03,990 --> 01:19:01,760 yeah which won't bother you with raja 2251 01:19:05,110 --> 01:19:04,000 yeah we love the interest but we've done 2252 01:19:06,470 --> 01:19:05,120 it a couple times and we will 2253 01:19:08,790 --> 01:19:06,480 undoubtedly do it again 2254 01:19:12,070 --> 01:19:08,800 so um i will say one thing though about 2255 01:19:14,790 --> 01:19:12,080 dark matter and dark energy 2256 01:19:16,580 --> 01:19:14,800 dark matter sucks but dark energy is 2257 01:19:20,470 --> 01:19:16,590 truly repulsive 2258 01:19:21,830 --> 01:19:20,480 [Laughter] 2259 01:19:23,830 --> 01:19:21,840 observable but that doesn't mean you 2260 01:19:25,430 --> 01:19:23,840 have to like it like 2261 01:19:26,350 --> 01:19:25,440 no i literally mean it sucks since 2262 01:19:29,030 --> 01:19:26,360 gravity sucks 2263 01:19:31,189 --> 01:19:29,040 [Laughter] 2264 01:19:32,790 --> 01:19:31,199 all right so here's one that i like and 2265 01:19:36,390 --> 01:19:32,800 um we can talk about this 2266 01:19:39,830 --> 01:19:36,400 is how will jwst 2267 01:19:42,229 --> 01:19:39,840 slash roman impact the way that you are 2268 01:19:44,470 --> 01:19:42,239 doing your studies or what kind of new 2269 01:19:46,790 --> 01:19:44,480 observations or data 2270 01:19:48,390 --> 01:19:46,800 might you get that can further your 2271 01:19:50,709 --> 01:19:48,400 research 2272 01:19:52,149 --> 01:19:50,719 that's an excellent question um you know 2273 01:19:55,430 --> 01:19:52,159 the first round of 2274 01:19:56,630 --> 01:19:55,440 proposals uh to use the james webb space 2275 01:19:58,070 --> 01:19:56,640 telescope has 2276 01:19:59,910 --> 01:19:58,080 already gone in there was an early 2277 01:20:02,149 --> 01:19:59,920 release science observations that are 2278 01:20:04,390 --> 01:20:02,159 have already been approved but the cycle 2279 01:20:07,830 --> 01:20:04,400 one of the proposals happened 2280 01:20:10,629 --> 01:20:07,840 late last year i'm on 2281 01:20:12,229 --> 01:20:10,639 six of those teams a couple of them are 2282 01:20:16,629 --> 01:20:12,239 to study 2283 01:20:19,669 --> 01:20:16,639 the details of andromeda 2284 01:20:21,030 --> 01:20:19,679 one of those is to study very detailed 2285 01:20:24,470 --> 01:20:21,040 star formation 2286 01:20:26,709 --> 01:20:24,480 in the triangulum galaxy m33 2287 01:20:28,310 --> 01:20:26,719 some of them are one of them is to study 2288 01:20:29,430 --> 01:20:28,320 detail dark matter substructure in 2289 01:20:32,629 --> 01:20:29,440 distant galaxies 2290 01:20:34,390 --> 01:20:32,639 so jwst is you know like 2291 01:20:35,910 --> 01:20:34,400 any piece of modern technology and this 2292 01:20:36,629 --> 01:20:35,920 is a spectacular piece of modern 2293 01:20:38,310 --> 01:20:36,639 technology 2294 01:20:42,310 --> 01:20:38,320 it's really going to advance the field 2295 01:20:45,750 --> 01:20:44,229 and the roman space telescope you 2296 01:20:48,950 --> 01:20:45,760 mentioned in um 2297 01:20:51,510 --> 01:20:48,960 in discussing andromeda that being a 2298 01:20:54,310 --> 01:20:51,520 survey instrument it's going to get 2299 01:20:54,709 --> 01:20:54,320 you know 100 what is 320 million pixels 2300 01:20:57,830 --> 01:20:54,719 per 2301 01:20:58,709 --> 01:20:57,840 image at hubble resolution so this is 2302 01:21:01,189 --> 01:20:58,719 going to 2303 01:21:02,470 --> 01:21:01,199 you know allow us to gain a tremendous 2304 01:21:04,390 --> 01:21:02,480 amount of data 2305 01:21:06,550 --> 01:21:04,400 relatively quickly that and it's all 2306 01:21:09,830 --> 01:21:06,560 going to be non-proprietary so 2307 01:21:12,950 --> 01:21:09,840 it'll be open to the entire astronomical 2308 01:21:15,110 --> 01:21:12,960 community to go at that data 2309 01:21:16,390 --> 01:21:15,120 and you know really it's it's good it's 2310 01:21:19,910 --> 01:21:16,400 gonna 2311 01:21:22,070 --> 01:21:19,920 computers warm at night how about that 2312 01:21:23,830 --> 01:21:22,080 processing and analyzing it i think 2313 01:21:25,110 --> 01:21:23,840 roman will be fantastic not just for 2314 01:21:26,870 --> 01:21:25,120 andromeda and triangular it'll be 2315 01:21:29,030 --> 01:21:26,880 fantastic for the virgo cluster 2316 01:21:30,950 --> 01:21:29,040 i'm particularly excited about studying 2317 01:21:31,990 --> 01:21:30,960 star clusters globular star clusters in 2318 01:21:36,229 --> 01:21:32,000 virgo that's 2319 01:21:38,149 --> 01:21:36,239 going to be an amazing roman application 2320 01:21:39,669 --> 01:21:38,159 very much so and between the new 2321 01:21:42,310 --> 01:21:39,679 observations and 2322 01:21:44,229 --> 01:21:42,320 the double-blind studies that we do now 2323 01:21:46,470 --> 01:21:44,239 for science proposals and whatnot 2324 01:21:48,070 --> 01:21:46,480 like the merits coming from the actual 2325 01:21:49,750 --> 01:21:48,080 science themselves and not where people 2326 01:21:51,110 --> 01:21:49,760 come from or their universities or the 2327 01:21:51,990 --> 01:21:51,120 background and that sort of thing in 2328 01:21:54,629 --> 01:21:52,000 addition to 2329 01:21:56,070 --> 01:21:54,639 a lot of the new information especially 2330 01:21:57,510 --> 01:21:56,080 the larger breadth 2331 01:21:59,990 --> 01:21:57,520 of infrared light that we'll be able to 2332 01:22:01,750 --> 01:22:00,000 see with jwst coming so soon like 2333 01:22:04,310 --> 01:22:01,760 there's a lot of potential for us to 2334 01:22:07,669 --> 01:22:04,320 delve a lot deeper 2335 01:22:09,750 --> 01:22:07,679 especially into emissions and uh 2336 01:22:12,229 --> 01:22:09,760 like atmospheres for exoplanets but for 2337 01:22:13,669 --> 01:22:12,239 black holes there's definitely a lot 2338 01:22:17,910 --> 01:22:13,679 more spectrum that you're going to be 2339 01:22:21,270 --> 01:22:19,590 grant i do want to pick up on one thing 2340 01:22:22,709 --> 01:22:21,280 you just said which is 2341 01:22:25,030 --> 01:22:22,719 something that space telescope's been 2342 01:22:27,910 --> 01:22:25,040 such a leader in which is 2343 01:22:28,550 --> 01:22:27,920 this double-blind process of being fair 2344 01:22:31,990 --> 01:22:28,560 in 2345 01:22:34,149 --> 01:22:32,000 it's really been a 2346 01:22:36,709 --> 01:22:34,159 leader in science for this it's to say 2347 01:22:39,030 --> 01:22:36,719 that the power of your storytelling 2348 01:22:40,550 --> 01:22:39,040 in that proposal is what should get you 2349 01:22:42,550 --> 01:22:40,560 telescope time 2350 01:22:44,149 --> 01:22:42,560 not where you've been for the last 25 2351 01:22:46,390 --> 01:22:44,159 years or what institution you 2352 01:22:48,550 --> 01:22:46,400 are or aren't at whether you're male or 2353 01:22:49,910 --> 01:22:48,560 female what the color of your skin is 2354 01:22:51,910 --> 01:22:49,920 none of these things should matter the 2355 01:22:52,550 --> 01:22:51,920 power of your storytelling divorced from 2356 01:22:53,910 --> 01:22:52,560 your name 2357 01:22:55,669 --> 01:22:53,920 divorced from all other personal 2358 01:22:56,790 --> 01:22:55,679 identity is what should get you 2359 01:22:57,510 --> 01:22:56,800 telescope time and that's been a 2360 01:23:00,950 --> 01:22:57,520 wonderful 2361 01:23:02,950 --> 01:23:00,960 led i just want to applaud that 2362 01:23:04,229 --> 01:23:02,960 and i will note that nasa has adopted 2363 01:23:06,229 --> 01:23:04,239 that for all of their 2364 01:23:07,750 --> 01:23:06,239 uh peer review systems now going forward 2365 01:23:10,149 --> 01:23:07,760 so that's wonderful 2366 01:23:11,590 --> 01:23:10,159 it's great that it was a great it's a 2367 01:23:13,189 --> 01:23:11,600 great advancement 2368 01:23:16,149 --> 01:23:13,199 we should all be judged by the content 2369 01:23:19,669 --> 01:23:18,229 all right so i think i've got one last 2370 01:23:19,990 --> 01:23:19,679 question i'm getting a couple in the 2371 01:23:22,790 --> 01:23:20,000 chat 2372 01:23:24,470 --> 01:23:22,800 here and i feel like that's a reasonable 2373 01:23:26,950 --> 01:23:24,480 reasonable place to wrap up 2374 01:23:27,669 --> 01:23:26,960 okay is that okay or do we have time for 2375 01:23:30,550 --> 01:23:27,679 a couple more 2376 01:23:31,750 --> 01:23:30,560 we got at least one more let's okay so 2377 01:23:34,149 --> 01:23:31,760 um 2378 01:23:36,229 --> 01:23:34,159 oh here's a good personal one how do the 2379 01:23:37,270 --> 01:23:36,239 telescopes in chile compare with the 2380 01:23:46,149 --> 01:23:37,280 telescopes 2381 01:23:48,390 --> 01:23:46,159 these mountain tops of course and 2382 01:23:49,990 --> 01:23:48,400 there are many mountain tops in chile as 2383 01:23:51,270 --> 01:23:50,000 well many mountain tops in hawaii i 2384 01:23:54,470 --> 01:23:51,280 suppose there's 2385 01:23:55,510 --> 01:23:54,480 haleakala as well as mauna kea houses 2386 01:23:57,990 --> 01:23:55,520 telescopes 2387 01:23:58,629 --> 01:23:58,000 um i've i've been privileged enough to 2388 01:24:02,149 --> 01:23:58,639 use 2389 01:24:05,189 --> 01:24:02,159 two mountain tops in chile tololo 2390 01:24:08,390 --> 01:24:05,199 and and las campanas 2391 01:24:11,350 --> 01:24:08,400 and they are different 2392 01:24:13,990 --> 01:24:11,360 in the sense that in one case you're 2393 01:24:15,110 --> 01:24:14,000 surrounded by the ocean 2394 01:24:17,270 --> 01:24:15,120 when you're on mauna kea you're 2395 01:24:18,870 --> 01:24:17,280 surrounded by the ocean and i would have 2396 01:24:22,709 --> 01:24:18,880 to say that the 2397 01:24:25,750 --> 01:24:22,719 laminar flow of air over mauna kea 2398 01:24:27,350 --> 01:24:25,760 is in my experience unparalleled 2399 01:24:30,870 --> 01:24:27,360 uh compared to the other observatories 2400 01:24:33,270 --> 01:24:30,880 i've been to chile 2401 01:24:35,350 --> 01:24:33,280 tololo in particular is about the 2402 01:24:36,550 --> 01:24:35,360 darkest place i've ever been in i 2403 01:24:40,950 --> 01:24:36,560 remember 2404 01:24:42,790 --> 01:24:40,960 walking out during a night moon had set 2405 01:24:45,030 --> 01:24:42,800 i was walking from one observatory to 2406 01:24:46,950 --> 01:24:45,040 the other and 2407 01:24:48,870 --> 01:24:46,960 people told me if you look carefully you 2408 01:24:52,229 --> 01:24:48,880 can see your own shadow cast by 2409 01:24:55,270 --> 01:24:52,239 jupiter it's no 2410 01:24:56,470 --> 01:24:55,280 so each observatory you know the dryness 2411 01:24:59,669 --> 01:24:56,480 the clear skies 2412 01:25:01,750 --> 01:24:59,679 of chile spectacular the darkness 2413 01:25:03,510 --> 01:25:01,760 spectacular sadly these things are 2414 01:25:05,430 --> 01:25:03,520 changing with time as human civilization 2415 01:25:06,790 --> 01:25:05,440 encroaches more and more into the 2416 01:25:09,430 --> 01:25:06,800 into the pristine environment these 2417 01:25:12,390 --> 01:25:09,440 things are changing all the time 2418 01:25:13,590 --> 01:25:12,400 any budding uh young astronomers or new 2419 01:25:15,669 --> 01:25:13,600 telescope 2420 01:25:16,950 --> 01:25:15,679 users i always say like be careful of 2421 01:25:18,950 --> 01:25:16,960 your light pollution because you don't 2422 01:25:20,310 --> 01:25:18,960 think about it but like 2423 01:25:21,830 --> 01:25:20,320 if you're in the middle of a city it 2424 01:25:24,950 --> 01:25:21,840 doesn't matter how good your telescope 2425 01:25:27,990 --> 01:25:24,960 is to a certain point like 2426 01:25:30,790 --> 01:25:28,000 yeah location location location okay 2427 01:25:31,189 --> 01:25:30,800 so any last one any last questions for 2428 01:25:35,270 --> 01:25:31,199 us 2429 01:25:36,950 --> 01:25:35,280 grant um i'm seeing a few but most of 2430 01:25:39,910 --> 01:25:36,960 them still talking about 2431 01:25:40,390 --> 01:25:39,920 uh either galaxy collision or dark 2432 01:25:42,229 --> 01:25:40,400 matter 2433 01:25:44,149 --> 01:25:42,239 there was there was one i i see here all 2434 01:25:45,910 --> 01:25:44,159 right okay so they wanted to correlate 2435 01:25:48,709 --> 01:25:45,920 two of the things you talked about 2436 01:25:51,189 --> 01:25:48,719 um the milky way andromeda collision and 2437 01:25:53,750 --> 01:25:51,199 the detection of gravitational waves 2438 01:25:55,030 --> 01:25:53,760 would we expect that the collision of 2439 01:26:00,070 --> 01:25:55,040 galaxies 2440 01:26:03,750 --> 01:26:01,750 they do create gravitational waves of 2441 01:26:05,189 --> 01:26:03,760 course any kind of change like that but 2442 01:26:07,430 --> 01:26:05,199 it's not detectable 2443 01:26:09,669 --> 01:26:07,440 in the foreseeable future you need 2444 01:26:12,229 --> 01:26:09,679 things to be much more compact 2445 01:26:13,669 --> 01:26:12,239 and much more intense the gravitational 2446 01:26:14,950 --> 01:26:13,679 field has to be much more intense you 2447 01:26:16,950 --> 01:26:14,960 really need supermassive 2448 01:26:19,030 --> 01:26:16,960 you need black holes or neutron stars 2449 01:26:20,790 --> 01:26:19,040 colliding with current technology and 2450 01:26:24,070 --> 01:26:20,800 for the foreseeable future 2451 01:26:25,350 --> 01:26:24,080 the the gravity waves produced by galaxy 2452 01:26:27,350 --> 01:26:25,360 collisions 2453 01:26:28,870 --> 01:26:27,360 just by the entire bodies of galaxies 2454 01:26:30,470 --> 01:26:28,880 colliding is way too weak 2455 01:26:32,310 --> 01:26:30,480 the black holes at their centers of 2456 01:26:33,910 --> 01:26:32,320 course are likely to emerge and that 2457 01:26:35,910 --> 01:26:33,920 will lead to gravity waves so 2458 01:26:37,750 --> 01:26:35,920 yes there's a link through that 2459 01:26:39,270 --> 01:26:37,760 mechanism but since the 2460 01:26:41,350 --> 01:26:39,280 collision itself isn't going to happen 2461 01:26:41,830 --> 01:26:41,360 for like four billion years and then you 2462 01:26:43,270 --> 01:26:41,840 know 2463 01:26:45,030 --> 01:26:43,280 getting those black holes together it'll 2464 01:26:47,350 --> 01:26:45,040 take another few billion years 2465 01:26:49,270 --> 01:26:47,360 uh we're unlikely or even even our 2466 01:26:51,430 --> 01:26:49,280 graduate students are unlikely to still 2467 01:26:52,629 --> 01:26:51,440 be astronomers at that time 2468 01:26:53,990 --> 01:26:52,639 on the other hand we have a lot of time 2469 01:26:56,470 --> 01:26:54,000 to build this brand new technology 2470 01:27:02,310 --> 01:27:00,149 true all right well thank you grant 2471 01:27:04,229 --> 01:27:02,320 uh for monitoring it was an incredibly 2472 01:27:05,110 --> 01:27:04,239 active chat thank you to all of our 2473 01:27:07,430 --> 01:27:05,120 watchers 2474 01:27:09,750 --> 01:27:07,440 for making that chat so active and most 2475 01:27:13,510 --> 01:27:09,760 of all thank you to raja for 2476 01:27:15,350 --> 01:27:13,520 a wonderful talk a wide ranging talk 2477 01:27:16,950 --> 01:27:15,360 if you want to know more about the milky 2478 01:27:19,750 --> 01:27:16,960 way andromeda collision 2479 01:27:21,830 --> 01:27:19,760 well then join us on february 2nd 2480 01:27:23,510 --> 01:27:21,840 groundhog day when laura pritchard from 2481 01:27:25,669 --> 01:27:23,520 the space telescope science institute 2482 01:27:28,149 --> 01:27:25,679 will give a complete talk about that and 2483 01:27:28,950 --> 01:27:28,159 she'll go into all sorts of details on 2484 01:27:31,750 --> 01:27:28,960 that 2485 01:27:32,950 --> 01:27:31,760 so thank you all for coming tonight and