1 00:00:09,740 --> 00:00:02,750 upcast and pulling it to youtube so give 2 00:00:13,360 --> 00:00:09,750 grant a hand alright let me start the 3 00:00:30,909 --> 00:00:28,870 I'm sure this working as you came in if 4 00:00:33,790 --> 00:00:30,919 you saw these on the table we have our 5 00:00:36,549 --> 00:00:33,800 lithographs tonight's lithograph is of 6 00:00:38,770 --> 00:00:36,559 30 Doradus a turbulent star-forming 7 00:00:41,020 --> 00:00:38,780 region which really should be called the 8 00:00:42,520 --> 00:00:41,030 tarantula nebula because 30 Doradus is 9 00:00:44,950 --> 00:00:42,530 just basically the star cluster at the 10 00:00:47,349 --> 00:00:44,960 heart of it it was originally it was so 11 00:00:48,490 --> 00:00:47,359 bright it was thought to be a star but 12 00:00:50,439 --> 00:00:48,500 it's now a said known to be a star 13 00:00:52,900 --> 00:00:50,449 cluster and actually it's a part of a 14 00:00:55,029 --> 00:00:52,910 big nebula called the tarantula nebula 15 00:00:57,880 --> 00:00:55,039 if you'd like to learn more about it 16 00:01:00,430 --> 00:00:57,890 it's on the back and it talks about star 17 00:01:01,810 --> 00:01:00,440 formation but you don't have to read you 18 00:01:04,360 --> 00:01:01,820 can listen to will tonight because he's 19 00:01:06,100 --> 00:01:04,370 gonna tell you everything you wanted to 20 00:01:10,060 --> 00:01:06,110 know about star formation because our 21 00:01:12,399 --> 00:01:10,070 talk tonight is star formation in Orion 22 00:01:16,120 --> 00:01:12,409 one of my favorite places in the 23 00:01:18,520 --> 00:01:16,130 universe next month we will have the 24 00:01:21,640 --> 00:01:18,530 Milky Way's bulge from a hypothesized 25 00:01:24,070 --> 00:01:21,650 blob to a remarkably detailed picture I 26 00:01:26,740 --> 00:01:24,080 actually wanted to call this the blob 27 00:01:30,250 --> 00:01:26,750 that ate the Milky Way but David didn't 28 00:01:33,100 --> 00:01:30,260 seem to like that title in August 29 00:01:36,490 --> 00:01:33,110 ashes to ashes dust to dust the fate of 30 00:01:40,690 --> 00:01:36,500 stars like the Sun death of stars in 31 00:01:43,630 --> 00:01:40,700 August and in September more death and 32 00:01:46,240 --> 00:01:43,640 destruction 100 ways to die in the 33 00:01:51,670 --> 00:01:46,250 universe I really don't know what that 34 00:01:53,860 --> 00:01:51,680 talk is about but if you would like to 35 00:01:56,770 --> 00:01:53,870 find out more about to keep remind 36 00:01:58,690 --> 00:01:56,780 yourself of these talks we have our web 37 00:02:00,640 --> 00:01:58,700 page you take go to your favorite search 38 00:02:02,710 --> 00:02:00,650 engine and type o hubble public talks 39 00:02:04,780 --> 00:02:02,720 you'll find this page we have our list 40 00:02:07,710 --> 00:02:04,790 of the upcoming lectures we have the 41 00:02:10,600 --> 00:02:07,720 links to the live webcasting both on our 42 00:02:13,330 --> 00:02:10,610 STScI webcasting site as well as on 43 00:02:18,460 --> 00:02:13,340 youtube we have the archives all the way 44 00:02:21,309 --> 00:02:18,470 back to 2005 from STFC i so you can get 45 00:02:23,500 --> 00:02:21,319 your fill of astronomy should you wake 46 00:02:25,360 --> 00:02:23,510 up at 3 in the morning go I really need 47 00:02:28,420 --> 00:02:25,370 some astronomy right now 48 00:02:32,330 --> 00:02:28,430 you can also sign up for our email list 49 00:02:33,980 --> 00:02:32,340 here let's see the announcements if you 50 00:02:35,660 --> 00:02:33,990 sign up to the website we'll just send 51 00:02:37,760 --> 00:02:35,670 you a really only send you like one or 52 00:02:39,620 --> 00:02:37,770 two emails a month selling reminding you 53 00:02:41,120 --> 00:02:39,630 of the upcoming lectures and telling you 54 00:02:43,400 --> 00:02:41,130 where you can find the webcast when it 55 00:02:45,500 --> 00:02:43,410 is posted if you have comments or 56 00:02:51,020 --> 00:02:45,510 questions you can send them to us at 57 00:02:52,970 --> 00:02:51,030 public lecture at STScI edu social media 58 00:02:54,860 --> 00:02:52,980 should you want to follow us on these 59 00:02:56,330 --> 00:02:54,870 various things we have facebook we have 60 00:02:59,090 --> 00:02:56,340 twitter we have YouTube we have 61 00:03:03,470 --> 00:02:59,100 Instagram and we have two or three on 62 00:03:06,410 --> 00:03:03,480 each of those channels for your social 63 00:03:08,390 --> 00:03:06,420 media pleasure myself I'm on Facebook 64 00:03:12,380 --> 00:03:08,400 Google+ and Twitter but I'm not very 65 00:03:15,740 --> 00:03:12,390 active so don't expect daily tweets from 66 00:03:17,930 --> 00:03:15,750 me Observatory I got the email from 67 00:03:19,970 --> 00:03:17,940 ireenie and she said it's just cloudy 68 00:03:22,520 --> 00:03:19,980 all evening so we will not have the 69 00:03:24,710 --> 00:03:22,530 observatory open after the lecture but 70 00:03:27,950 --> 00:03:24,720 as we remind you every month they do 71 00:03:31,580 --> 00:03:27,960 have open houses on Friday evenings you 72 00:03:33,020 --> 00:03:31,590 go to MD dot space grant org you find 73 00:03:35,090 --> 00:03:33,030 their Observatory page and this 74 00:03:38,000 --> 00:03:35,100 Observatory status box over here on the 75 00:03:39,260 --> 00:03:38,010 right will tell you what whether or not 76 00:03:41,150 --> 00:03:39,270 they're gonna be open basically you 77 00:03:42,650 --> 00:03:41,160 check it Friday at around 5:00 or 6:00 78 00:03:44,300 --> 00:03:42,660 and they'll tell you whether they're 79 00:03:48,020 --> 00:03:44,310 gonna be open sort of like the email I 80 00:03:50,660 --> 00:03:48,030 get every time we have to lecture okay 81 00:03:53,350 --> 00:03:50,670 and now our news from the universe for 82 00:03:59,630 --> 00:03:53,360 June 2018 83 00:04:02,780 --> 00:03:59,640 our first story a galaxy tug of war well 84 00:04:04,940 --> 00:04:02,790 let's start with our galaxy okay so this 85 00:04:07,310 --> 00:04:04,950 is an all-sky view of our Milky Way 86 00:04:08,960 --> 00:04:07,320 galaxy and you can see right across the 87 00:04:11,840 --> 00:04:08,970 center here is the plane of our Milky 88 00:04:14,120 --> 00:04:11,850 Way galaxy it's a disc shaped galaxy and 89 00:04:18,470 --> 00:04:14,130 we're inside that disc so we see it as 90 00:04:21,050 --> 00:04:18,480 this long straight structure heading all 91 00:04:23,000 --> 00:04:21,060 the way across the sky but there are 92 00:04:25,190 --> 00:04:23,010 other galaxies in this image all right 93 00:04:28,280 --> 00:04:25,200 you may not know them as galaxies but 94 00:04:31,280 --> 00:04:28,290 you have this spot down here this spot 95 00:04:35,790 --> 00:04:31,290 down here they are nearby galaxies this 96 00:04:38,460 --> 00:04:35,800 one is called the Large Magellanic Cloud 97 00:04:41,460 --> 00:04:38,470 yeah they're called Magellanic because 98 00:04:44,580 --> 00:04:41,470 they were discovered by Magellan on his 99 00:04:46,170 --> 00:04:44,590 trip around the world actually they 100 00:04:47,640 --> 00:04:46,180 can't say that Magellan discovered them 101 00:04:49,350 --> 00:04:47,650 because it was just he was the first 102 00:04:52,110 --> 00:04:49,360 Europe he brought back the news of these 103 00:04:53,820 --> 00:04:52,120 objects to Europe of course anybody can 104 00:04:56,610 --> 00:04:53,830 see them they just look up if you're in 105 00:04:58,920 --> 00:04:56,620 the southern hemisphere unfortunately we 106 00:05:00,059 --> 00:04:58,930 can't see them here from Baltimore but 107 00:05:02,490 --> 00:05:00,069 if you do get down in the southern 108 00:05:04,860 --> 00:05:02,500 hemisphere you must look up get find a 109 00:05:07,439 --> 00:05:04,870 dark spot and it's just beautiful to see 110 00:05:09,240 --> 00:05:07,449 these these clouds up there in the sky 111 00:05:10,589 --> 00:05:09,250 so that's the large magellanic cloud and 112 00:05:14,520 --> 00:05:10,599 if there's a large magellanic cloud 113 00:05:16,589 --> 00:05:14,530 there's also a small magellanic cloud 114 00:05:20,820 --> 00:05:16,599 yes this is the small Magellanic Cloud 115 00:05:23,249 --> 00:05:20,830 now these two clouds are not clouds they 116 00:05:25,200 --> 00:05:23,259 look kind of cloudy when viewed with the 117 00:05:27,809 --> 00:05:25,210 human eye but as you can see from these 118 00:05:30,240 --> 00:05:27,819 images they're composed of millions of 119 00:05:33,149 --> 00:05:30,250 stars they are actually satellite 120 00:05:35,999 --> 00:05:33,159 galaxies of the Milky Way the LMC and 121 00:05:37,950 --> 00:05:36,009 the SMC are two satellite galaxies 122 00:05:40,769 --> 00:05:37,960 they're actually orbiting around the 123 00:05:43,170 --> 00:05:40,779 Milky Way how do we know that they are 124 00:05:44,850 --> 00:05:43,180 orbiting well we can measure their 125 00:05:47,879 --> 00:05:44,860 dynamics and everything but it's 126 00:05:50,640 --> 00:05:47,889 actually kind of easy when you look at 127 00:05:54,240 --> 00:05:50,650 them in radio light because in radio 128 00:05:56,519 --> 00:05:54,250 light you see this sorry I changed the 129 00:05:58,769 --> 00:05:56,529 Milky Way from a longitude latitude 130 00:06:02,089 --> 00:05:58,779 projection to what this is an eighth off 131 00:06:04,830 --> 00:06:02,099 all sky projection but here are the 132 00:06:07,019 --> 00:06:04,840 large and small Magellanic Clouds and 133 00:06:09,959 --> 00:06:07,029 you see this radio light coming along 134 00:06:12,209 --> 00:06:09,969 here okay and you see all this junk up 135 00:06:14,369 --> 00:06:12,219 here also associated with Magellanic 136 00:06:16,709 --> 00:06:14,379 Clouds okay so let me put on some some 137 00:06:19,320 --> 00:06:16,719 graphics we've got the LMC and the SMC 138 00:06:23,999 --> 00:06:19,330 and then this is called the Magellanic 139 00:06:27,420 --> 00:06:24,009 stream okay and this is understood to be 140 00:06:30,029 --> 00:06:27,430 material that has been pulled out of the 141 00:06:31,890 --> 00:06:30,039 large and small Magellanic Clouds due to 142 00:06:34,529 --> 00:06:31,900 this sort of tug-of-war as they're 143 00:06:37,379 --> 00:06:34,539 orbiting around gravity pulls on these 144 00:06:39,540 --> 00:06:37,389 galaxies and if you've got the Milky Way 145 00:06:41,459 --> 00:06:39,550 which is a large galaxy and you've got 146 00:06:43,200 --> 00:06:41,469 the LMC and the SMC which are small 147 00:06:47,490 --> 00:06:43,210 galaxies and they're in a tug-of-war 148 00:06:49,629 --> 00:06:47,500 who's gonna win yeah you can see here 149 00:06:51,909 --> 00:06:49,639 the out of the Milky Way galaxy 150 00:06:55,089 --> 00:06:51,919 is gonna win and you get this big title 151 00:06:56,770 --> 00:06:55,099 tail of material that we previously used 152 00:06:58,420 --> 00:06:56,780 Hubble observations to understand that 153 00:07:00,969 --> 00:06:58,430 they kept this material actually 154 00:07:04,269 --> 00:07:00,979 contains material from both the SMC and 155 00:07:07,390 --> 00:07:04,279 the LMC now that's sort of what we call 156 00:07:09,519 --> 00:07:07,400 the trailing arm of a title interaction 157 00:07:11,739 --> 00:07:09,529 stuff that's pulled out okay but stuff 158 00:07:13,269 --> 00:07:11,749 also pulls out on the near side due to 159 00:07:15,279 --> 00:07:13,279 the gravitational interactions these 160 00:07:17,679 --> 00:07:15,289 tidal interactions and this is the 161 00:07:20,140 --> 00:07:17,689 leading arm of it and that stuff is 162 00:07:23,080 --> 00:07:20,150 actually falling into and interacting 163 00:07:25,240 --> 00:07:23,090 with the Milky Way and we do not know 164 00:07:29,550 --> 00:07:25,250 where that leading arm material comes 165 00:07:32,019 --> 00:07:29,560 from and if you just look at it sort of 166 00:07:34,510 --> 00:07:32,029 geometrically right it's closer to the 167 00:07:38,730 --> 00:07:34,520 LMC and you say oh maybe that stuff is 168 00:07:42,850 --> 00:07:38,740 from the LMC dynamically you can't tell 169 00:07:45,459 --> 00:07:42,860 however you can tell if you use spectra 170 00:07:48,610 --> 00:07:45,469 all right so what we did is we found 171 00:07:51,219 --> 00:07:48,620 three quasars these are very distant 172 00:07:53,200 --> 00:07:51,229 very bright objects and their light is 173 00:07:56,260 --> 00:07:53,210 actually shining through this material 174 00:07:59,170 --> 00:07:56,270 and so we can look in the spectrum of 175 00:08:02,140 --> 00:07:59,180 the quasar to see what type of material 176 00:08:05,529 --> 00:08:02,150 is in this leading arm so here are the 177 00:08:08,379 --> 00:08:05,539 spectra all right quasar a quasar being 178 00:08:10,450 --> 00:08:08,389 quasar C and these are just uh you know 179 00:08:11,969 --> 00:08:10,460 graphic artist versions of them to show 180 00:08:15,389 --> 00:08:11,979 the hydrogen and the oxygen 181 00:08:18,850 --> 00:08:15,399 concentration in these various spectra 182 00:08:21,129 --> 00:08:18,860 so what we're looking at is what is the 183 00:08:24,519 --> 00:08:21,139 relative abundance of hydrogen and 184 00:08:26,559 --> 00:08:24,529 oxygen in this material and does it 185 00:08:29,320 --> 00:08:26,569 match the hydrogen oxygen abundance in 186 00:08:33,870 --> 00:08:29,330 the LMC or the SMC or is it a little bit 187 00:08:38,139 --> 00:08:33,880 of both the answer is it's from the SMC 188 00:08:40,149 --> 00:08:38,149 so the conclusion is that the LMC is 189 00:08:42,759 --> 00:08:40,159 pulling more material out of the SMC 190 00:08:44,860 --> 00:08:42,769 that is then falling in to form this 191 00:08:46,449 --> 00:08:44,870 leading arm at least these three signs 192 00:08:49,000 --> 00:08:46,459 that actually I think there were seven 193 00:08:53,199 --> 00:08:49,010 lines of sight through the leading arm 194 00:08:57,000 --> 00:08:53,209 and the oxygen to hydrogen ratio matches 195 00:08:59,110 --> 00:08:57,010 that of the SMC and not that of the LMC 196 00:09:00,639 --> 00:08:59,120 indicating that when you go with a large 197 00:09:02,850 --> 00:09:00,649 magellanic cloud versus the small 198 00:09:05,190 --> 00:09:02,860 magellanic cloud in a tug-of-war 199 00:09:07,920 --> 00:09:05,200 who's gonna win the Large Magellanic 200 00:09:10,110 --> 00:09:07,930 Cloud seems to win and that material is 201 00:09:11,490 --> 00:09:10,120 as can be traced back to the SMC and 202 00:09:14,460 --> 00:09:11,500 this is the first time we've been able 203 00:09:16,440 --> 00:09:14,470 to get the full understanding of this 204 00:09:18,450 --> 00:09:16,450 full Magellanic stream of these dwarf 205 00:09:20,490 --> 00:09:18,460 galaxies and they're losing you know 206 00:09:22,130 --> 00:09:20,500 just a small bit of the material as they 207 00:09:29,430 --> 00:09:22,140 orbit around the Milky Way 208 00:09:32,250 --> 00:09:29,440 yes question I don't know what has to be 209 00:09:34,050 --> 00:09:32,260 hundreds of millions of years could be 210 00:09:37,710 --> 00:09:34,060 as much as 500 million years do you know 211 00:09:39,870 --> 00:09:37,720 will yeah he he would guess the same 212 00:09:41,690 --> 00:09:39,880 amount so uh a few hundred million years 213 00:09:44,400 --> 00:09:41,700 maybe five hundred million years because 214 00:09:46,830 --> 00:09:44,410 our Sun orbiting within the Milky Way is 215 00:09:48,840 --> 00:09:46,840 200 250 million years and that of that 216 00:09:51,120 --> 00:09:48,850 timeframe so these are already way 217 00:09:56,040 --> 00:09:51,130 outside so I got to give it probably 218 00:09:58,080 --> 00:09:56,050 about 500 million okay yes they're there 219 00:10:00,210 --> 00:09:58,090 they're not in the plane they are if the 220 00:10:01,860 --> 00:10:00,220 plane is here they're down here and 221 00:10:05,280 --> 00:10:01,870 they're coming and we're not exactly 222 00:10:07,380 --> 00:10:05,290 sure they're of their exact orbit you 223 00:10:09,780 --> 00:10:07,390 can sort of trace and get a get a feel 224 00:10:12,780 --> 00:10:09,790 for it from the dynamics of that but 225 00:10:14,520 --> 00:10:12,790 it's it's it's still there's still 226 00:10:37,710 --> 00:10:14,530 significant uncertainty in the exact 227 00:10:40,620 --> 00:10:37,720 orbits of them okay yes okay so you're 228 00:10:42,990 --> 00:10:40,630 asking alright how far out into the 229 00:10:45,540 --> 00:10:43,000 Milky Way can we see with the human eye 230 00:10:46,730 --> 00:10:45,550 you're seeing just a small region of the 231 00:10:48,840 --> 00:10:46,740 Milky Way 232 00:10:50,160 --> 00:10:48,850 you didn't mean there's certain things 233 00:10:52,740 --> 00:10:50,170 that you can see that are really far 234 00:10:55,320 --> 00:10:52,750 away but most of all the stars you can 235 00:10:57,330 --> 00:10:55,330 see with the the human eye are about the 236 00:10:59,550 --> 00:10:57,340 size of a sausage on a 16 inch pizza 237 00:11:01,530 --> 00:10:59,560 okay that's the volume that you can see 238 00:11:02,820 --> 00:11:01,540 and maybe if you include all the other 239 00:11:06,030 --> 00:11:02,830 stuff you can see it gets out to the 240 00:11:08,490 --> 00:11:06,040 size about pepperoni on a pizza but you 241 00:11:08,880 --> 00:11:08,500 really can't see much much further than 242 00:11:12,270 --> 00:11:08,890 that 243 00:11:13,320 --> 00:11:12,280 okay questions about the the news story 244 00:11:14,880 --> 00:11:13,330 because I don't want to eat into wills 245 00:11:17,430 --> 00:11:14,890 time yeah 246 00:11:19,710 --> 00:11:17,440 in the arm is that dust or is it are 247 00:11:21,720 --> 00:11:19,720 there stars in there yes the the the 248 00:11:23,220 --> 00:11:21,730 with it within the spiral galaxy we have 249 00:11:27,750 --> 00:11:23,230 a lot of dust and we have a lot of stars 250 00:11:30,000 --> 00:11:27,760 the spiral arms contain both oh these 251 00:11:33,840 --> 00:11:30,010 are the these Magellanic streams no this 252 00:11:36,600 --> 00:11:33,850 is just I assume its hydrogen gas that 253 00:11:38,580 --> 00:11:36,610 you would decked in the radio there will 254 00:11:40,890 --> 00:11:38,590 be you know there will be some stars in 255 00:11:42,420 --> 00:11:40,900 this but it's not place where stars 256 00:11:44,060 --> 00:11:42,430 would be made because it's very diffused 257 00:11:49,650 --> 00:11:44,070 material okay 258 00:11:52,410 --> 00:11:49,660 second-story exoplanet helium alright so 259 00:11:54,570 --> 00:11:52,420 uh we all took him how many of you took 260 00:11:55,890 --> 00:11:54,580 chemistry or will take chemistry for the 261 00:11:57,360 --> 00:11:55,900 for the young kids in the audience right 262 00:11:59,100 --> 00:11:57,370 put your hands up you're gonna take 263 00:12:00,720 --> 00:11:59,110 chemistry right he's Peter you're gonna 264 00:12:03,750 --> 00:12:00,730 make sure she takes chemistry okay good 265 00:12:05,670 --> 00:12:03,760 alright if you took chemistry you 266 00:12:07,590 --> 00:12:05,680 remember the periodic table of the 267 00:12:11,730 --> 00:12:07,600 elements and maybe you remember with 268 00:12:14,130 --> 00:12:11,740 dread but it's a really cool diagram 269 00:12:17,130 --> 00:12:14,140 okay it really puts things in lots of 270 00:12:20,220 --> 00:12:17,140 order but there's a ton of elements out 271 00:12:22,860 --> 00:12:20,230 there okay there's a lot of really 272 00:12:25,170 --> 00:12:22,870 interesting stuff out there but for the 273 00:12:28,400 --> 00:12:25,180 universe we can simplify it we really 274 00:12:30,780 --> 00:12:28,410 only have to look it up here and up here 275 00:12:35,550 --> 00:12:30,790 because when we look at the content of 276 00:12:38,250 --> 00:12:35,560 the universe it's 75% hydrogen 23% 277 00:12:41,340 --> 00:12:38,260 helium and 2% other and that's by mass 278 00:12:42,930 --> 00:12:41,350 okay so it's mostly hydrogen helium and 279 00:12:45,420 --> 00:12:42,940 yeah there's all that other stuff okay 280 00:12:47,820 --> 00:12:45,430 which is why we astronomers talk about 281 00:12:50,970 --> 00:12:47,830 hydrogen helium and then heavy elements 282 00:12:53,130 --> 00:12:50,980 okay so when we look at that you know we 283 00:12:55,530 --> 00:12:53,140 can see hydrogen if we look at our Sun 284 00:12:57,990 --> 00:12:55,540 the composition of our Sun well that's 285 00:13:00,870 --> 00:12:58,000 pretty much the same hydrogen helium 286 00:13:02,400 --> 00:13:00,880 yeah and all this other stuff okay all 287 00:13:05,430 --> 00:13:02,410 the stuff that you really think of you 288 00:13:08,220 --> 00:13:05,440 know yeah that's just that's in the 289 00:13:11,250 --> 00:13:08,230 noise and even when you look at the 290 00:13:13,470 --> 00:13:11,260 giant planets Jupiter Saturn Uranus and 291 00:13:15,210 --> 00:13:13,480 Neptune this is a table you can see now 292 00:13:17,370 --> 00:13:15,220 this is not by mass this is by number 293 00:13:20,280 --> 00:13:17,380 eighty six and thirteen eighty eight 294 00:13:24,030 --> 00:13:20,290 eighty two eighty nineteen fifty most of 295 00:13:25,920 --> 00:13:24,040 all the stuff is hydrogen and helium all 296 00:13:27,319 --> 00:13:25,930 right so that's setting you up to 297 00:13:29,539 --> 00:13:27,329 understand that that this 298 00:13:33,949 --> 00:13:29,549 is really expected to be everywhere in 299 00:13:37,280 --> 00:13:33,959 the universe so we have found 3000 300 00:13:40,189 --> 00:13:37,290 extrasolar planets out there and a lot 301 00:13:42,799 --> 00:13:40,199 of these extrasolar planets we are able 302 00:13:45,289 --> 00:13:42,809 to we detect them by the transit method 303 00:13:47,720 --> 00:13:45,299 where the planet passes in front of its 304 00:13:50,449 --> 00:13:47,730 star and for certain ones that are 305 00:13:52,519 --> 00:13:50,459 nearby when that planet passes in front 306 00:13:54,769 --> 00:13:52,529 of a star and it's close enough to that 307 00:13:57,199 --> 00:13:54,779 star some of the light of the star goes 308 00:13:59,539 --> 00:13:57,209 through the atmosphere of that planet 309 00:14:02,269 --> 00:13:59,549 and if we take a picture when it's in 310 00:14:04,910 --> 00:14:02,279 front and when it's not in front and we 311 00:14:08,210 --> 00:14:04,920 subtract the two we get the spectrum of 312 00:14:10,879 --> 00:14:08,220 the atmosphere of the planet we can 313 00:14:13,489 --> 00:14:10,889 examine the atmospheres of other planets 314 00:14:17,449 --> 00:14:13,499 and so for example here is an example 315 00:14:19,999 --> 00:14:17,459 spectrum of planet called wasp 39b 316 00:14:22,489 --> 00:14:20,009 and these features here are associated 317 00:14:24,530 --> 00:14:22,499 with water molecules and these are 318 00:14:27,169 --> 00:14:24,540 associated with carbon dioxide and this 319 00:14:30,259 --> 00:14:27,179 is potassium and this is sodium and we 320 00:14:33,669 --> 00:14:30,269 have seen methane and we seen ammonia we 321 00:14:38,900 --> 00:14:33,679 have seen all sorts of species out there 322 00:14:40,549 --> 00:14:38,910 we've never seen helium which if given 323 00:14:42,769 --> 00:14:40,559 the intro that I did for this is kind of 324 00:14:45,530 --> 00:14:42,779 strange because you would expect there's 325 00:14:51,889 --> 00:14:45,540 a lot of helium out there and we have 326 00:14:55,879 --> 00:14:51,899 never seen it until obviously last 107 327 00:14:58,340 --> 00:14:55,889 be ok this is an artist illustration of 328 00:15:01,429 --> 00:14:58,350 it well it's actually you know this is 329 00:15:04,850 --> 00:15:01,439 not wasp 107 this is the Sun acting as a 330 00:15:08,239 --> 00:15:04,860 stunt double for wasp 107 and this would 331 00:15:10,429 --> 00:15:08,249 be wasps 107 be drawn in this and you 332 00:15:15,259 --> 00:15:10,439 can see it's got this very extended 333 00:15:18,939 --> 00:15:15,269 extended in wasp 107 be using infrared 334 00:15:21,930 --> 00:15:18,949 spectra we were finally able to detect 335 00:15:24,180 --> 00:15:21,940 helium 336 00:15:26,840 --> 00:15:24,190 in in in in the atmosphere of a planet 337 00:15:29,850 --> 00:15:26,850 and you might say well why did it take 338 00:15:31,620 --> 00:15:29,860 this special well first of all previous 339 00:15:35,760 --> 00:15:31,630 observations had been using visible 340 00:15:39,660 --> 00:15:35,770 light and ultraviolet light and they did 341 00:15:42,780 --> 00:15:39,670 not find the the helium and it turns out 342 00:15:44,430 --> 00:15:42,790 that you know the interesting lines that 343 00:15:49,110 --> 00:15:44,440 you want are can be found in the 344 00:15:52,110 --> 00:15:49,120 infrared but also lost 107 B is one of 345 00:15:55,380 --> 00:15:52,120 the lowest density giant planets we've 346 00:15:59,340 --> 00:15:55,390 ever discovered okay it is the same size 347 00:16:02,550 --> 00:15:59,350 as Jupiter but it's only 12% the mass of 348 00:16:04,769 --> 00:16:02,560 Jupiter that's really low density and 349 00:16:07,440 --> 00:16:04,779 these giant planets aren't very high 350 00:16:09,260 --> 00:16:07,450 density to begin with okay and they say 351 00:16:12,510 --> 00:16:09,270 that Saturn would float in a bathtub 352 00:16:15,090 --> 00:16:12,520 which is kind of funky but anyways it's 353 00:16:17,700 --> 00:16:15,100 lower density than water alright this is 354 00:16:20,250 --> 00:16:17,710 really really low density which means 355 00:16:23,070 --> 00:16:20,260 its atmosphere must be it's really 356 00:16:26,040 --> 00:16:23,080 really extended and must extend tens of 357 00:16:28,769 --> 00:16:26,050 thousands of kilometers out into space 358 00:16:31,680 --> 00:16:28,779 and it's because it's such a low density 359 00:16:34,050 --> 00:16:31,690 planet it has this really extended 360 00:16:36,350 --> 00:16:34,060 atmosphere it's in close to its star and 361 00:16:39,269 --> 00:16:36,360 they did the observations in infrared 362 00:16:41,970 --> 00:16:39,279 that they finally been able to discover 363 00:16:43,769 --> 00:16:41,980 helium in other planet atmospheres we 364 00:16:45,930 --> 00:16:43,779 always knew it inspected it would be 365 00:16:48,150 --> 00:16:45,940 there but it's really kind of nice to 366 00:16:50,400 --> 00:16:48,160 find what to expect and not be missing 367 00:16:52,290 --> 00:16:50,410 one of the the two primary elements in 368 00:16:55,560 --> 00:16:52,300 the universe in extrasolar planet 369 00:16:57,600 --> 00:16:55,570 atmospheres all right and so that's our 370 00:16:59,490 --> 00:16:57,610 news summary for tonight any other 371 00:17:07,650 --> 00:16:59,500 questions on the two stories I presented 372 00:17:08,970 --> 00:17:07,660 to here yes so the question of why we 373 00:17:10,679 --> 00:17:08,980 didn't find it in all the other planets 374 00:17:12,840 --> 00:17:10,689 is because this is an extended 375 00:17:15,900 --> 00:17:12,850 atmosphere without the extended 376 00:17:17,340 --> 00:17:15,910 atmosphere the helium layers aren't 377 00:17:19,260 --> 00:17:17,350 weren't exposed okay 378 00:17:21,199 --> 00:17:19,270 Alice that's the current understanding 379 00:17:23,880 --> 00:17:21,209 we'll have to detect it in a few more 380 00:17:25,980 --> 00:17:23,890 planets and a whole to get a 381 00:17:28,049 --> 00:17:25,990 statistical sense of when we can see 382 00:17:30,570 --> 00:17:28,059 helium and when we can't but now we know 383 00:17:32,860 --> 00:17:30,580 how to find it we will look at the other 384 00:17:35,800 --> 00:17:32,870 ones and see if we can get a 385 00:17:37,630 --> 00:17:35,810 enough to make a statistical argument as 386 00:17:39,910 --> 00:17:37,640 to exactly why we're not seeing in any 387 00:17:47,220 --> 00:17:39,920 other and any of the others okay all 388 00:17:52,360 --> 00:17:50,380 featured speaker tonight is dr. wil 389 00:17:54,700 --> 00:17:52,370 Fisher from here at the Space Telescope 390 00:17:56,500 --> 00:17:54,710 Science Institute he got his 391 00:17:59,890 --> 00:17:56,510 undergraduate degree at the University 392 00:18:05,410 --> 00:17:59,900 of Toledo then went on to do a postdoc 393 00:18:09,310 --> 00:18:05,420 was it Goddard first or Toledo for the 394 00:18:11,920 --> 00:18:09,320 post Oh Toledo for a postdoc and then to 395 00:18:13,780 --> 00:18:11,930 Goddard for that and then he came what 396 00:18:16,390 --> 00:18:13,790 did you come right here from Goddard yes 397 00:18:19,570 --> 00:18:16,400 okay so he came to us from Goddard only 398 00:18:22,240 --> 00:18:19,580 a year year-and-a-half ago and his work 399 00:18:26,080 --> 00:18:22,250 is as a support scientist for the cosmic 400 00:18:29,020 --> 00:18:26,090 origins spectrograph and when he is not 401 00:18:31,660 --> 00:18:29,030 doing his astronomy he is a father of an 402 00:18:33,520 --> 00:18:31,670 11 year old girl who has gotten 403 00:18:35,950 --> 00:18:33,530 interested in astronomy he tells me but 404 00:18:38,740 --> 00:18:35,960 from a special perspective she likes to 405 00:18:41,560 --> 00:18:38,750 explore the art of astronomy astronomy 406 00:18:43,870 --> 00:18:41,570 and art so he's leading his daughter 407 00:18:47,110 --> 00:18:43,880 into not just a stem career but a steam 408 00:18:49,570 --> 00:18:47,120 career science technology arts and 409 00:18:59,950 --> 00:18:49,580 mathematics so ladies and gentlemen dr. 410 00:19:00,280 --> 00:18:59,960 will Fisher well thanks for coming 411 00:19:03,370 --> 00:19:00,290 everyone 412 00:19:07,630 --> 00:19:03,380 to start here I'm showing you a picture 413 00:19:11,740 --> 00:19:07,640 of Orion from Mayer's famous atlas of 414 00:19:13,690 --> 00:19:11,750 1603 and he's looking at an image of 415 00:19:16,870 --> 00:19:13,700 Orion from the infrared astronomy 416 00:19:19,300 --> 00:19:16,880 satellite which orbited in the 1980s and 417 00:19:20,920 --> 00:19:19,310 you might imagine that Orion is a little 418 00:19:23,830 --> 00:19:20,930 bit puzzled to learn what he's really 419 00:19:26,380 --> 00:19:23,840 made up of I'm gonna be telling you all 420 00:19:28,660 --> 00:19:26,390 about Star formation in Orion and how we 421 00:19:30,700 --> 00:19:28,670 learn about this with a lot of different 422 00:19:34,420 --> 00:19:30,710 space telescopes and a few that aren't 423 00:19:36,700 --> 00:19:34,430 quite in space so one of the reasons 424 00:19:38,950 --> 00:19:36,710 that were interested in how stars form 425 00:19:40,540 --> 00:19:38,960 is all of these thousands of exoplanets 426 00:19:43,240 --> 00:19:40,550 that have been discovered over the last 427 00:19:45,289 --> 00:19:43,250 20 to 25 years this is an artist's 428 00:19:49,070 --> 00:19:45,299 rendition of some of those at 429 00:19:52,960 --> 00:19:49,080 so planets and they exists in a wide 430 00:19:55,430 --> 00:19:52,970 variety of densities and compositions 431 00:19:58,070 --> 00:19:55,440 they orbit at some pretty surprising 432 00:20:00,109 --> 00:19:58,080 distances from their stars and to 433 00:20:01,759 --> 00:20:00,119 understand how all this comes to exist 434 00:20:04,609 --> 00:20:01,769 we have to know how the parent stars 435 00:20:06,229 --> 00:20:04,619 form so this has given new importance to 436 00:20:11,919 --> 00:20:06,239 studies of star formation in the past 437 00:20:13,789 --> 00:20:11,929 few decades but star formation began 438 00:20:16,399 --> 00:20:13,799 quite some time ago 439 00:20:18,440 --> 00:20:16,409 I think of 1852 is the beginning of star 440 00:20:20,419 --> 00:20:18,450 formation studies this is when this 441 00:20:22,940 --> 00:20:20,429 astronomer pictured here John Russell 442 00:20:24,710 --> 00:20:22,950 hind discovered a nebula that we now 443 00:20:27,830 --> 00:20:24,720 known as Hines nebula and there is a 444 00:20:31,340 --> 00:20:27,840 star in that nebula called t-tauri if 445 00:20:33,200 --> 00:20:31,350 you see a star where its name begins 446 00:20:36,830 --> 00:20:33,210 with one or two capital letters that 447 00:20:38,570 --> 00:20:36,840 means it's a variable star T Tauri as a 448 00:20:41,509 --> 00:20:38,580 variable star changed in brightness 449 00:20:44,060 --> 00:20:41,519 somewhat irregularly over periods of 450 00:20:46,039 --> 00:20:44,070 days to weeks but the interesting thing 451 00:20:48,379 --> 00:20:46,049 about this discovery is that the nebula 452 00:20:51,409 --> 00:20:48,389 also varied in brightness along with the 453 00:20:53,359 --> 00:20:51,419 star so that's a sign that the star and 454 00:20:56,930 --> 00:20:53,369 the nebula are physically connected the 455 00:20:58,190 --> 00:20:56,940 star is embedded in the nebula people 456 00:21:01,669 --> 00:20:58,200 didn't know what to make of this at 457 00:21:03,889 --> 00:21:01,679 first but as time went on more of these 458 00:21:06,560 --> 00:21:03,899 T Tauri like stars were discovered and 459 00:21:10,310 --> 00:21:06,570 then finally in an important paper in 460 00:21:14,299 --> 00:21:10,320 1945 the astronomer Alfred joy laid out 461 00:21:17,269 --> 00:21:14,309 the class of T Tauri stars often a class 462 00:21:19,220 --> 00:21:17,279 of objects in the sky is named after the 463 00:21:20,899 --> 00:21:19,230 first one to be discovered and this is 464 00:21:22,879 --> 00:21:20,909 an important step in putting a science 465 00:21:24,529 --> 00:21:22,889 together to go from a single object to 466 00:21:26,779 --> 00:21:24,539 understanding that there's a collection 467 00:21:29,659 --> 00:21:26,789 of objects that all have similar 468 00:21:31,879 --> 00:21:29,669 observational properties this is a light 469 00:21:34,729 --> 00:21:31,889 curve of an example of a T Tauri star 470 00:21:37,639 --> 00:21:34,739 and when you plot a light curve high 471 00:21:40,039 --> 00:21:37,649 points are bright and low points are dim 472 00:21:41,869 --> 00:21:40,049 and you plot those against time so you 473 00:21:44,060 --> 00:21:41,879 can see over the course of about a month 474 00:21:46,729 --> 00:21:44,070 you have these irregular variations in a 475 00:21:49,279 --> 00:21:46,739 T Tauri star and the change in 476 00:21:52,519 --> 00:21:49,289 brightness here corresponds to about a 477 00:21:57,230 --> 00:21:52,529 factor of 10 or a little bit less than 478 00:21:58,520 --> 00:21:57,240 10 and he recognized that there were 11 479 00:22:00,380 --> 00:21:58,530 known stars that had 480 00:22:02,480 --> 00:22:00,390 herbs like this and they were all in 481 00:22:05,900 --> 00:22:02,490 nebulous regions of the sky in these 482 00:22:08,660 --> 00:22:05,910 clouds so these must all have something 483 00:22:10,120 --> 00:22:08,670 to do with each other and people started 484 00:22:12,290 --> 00:22:10,130 to try to make some sense of this 485 00:22:15,020 --> 00:22:12,300 scientific understanding began to 486 00:22:17,540 --> 00:22:15,030 develop and this is Cecilia Payne de 487 00:22:20,660 --> 00:22:17,550 pasión she is my daughter's scientific 488 00:22:22,340 --> 00:22:20,670 hero I guess you could say she was the 489 00:22:23,630 --> 00:22:22,350 one who discovered what stars are made 490 00:22:26,000 --> 00:22:23,640 of that they're mostly hydrogen and 491 00:22:27,170 --> 00:22:26,010 helium nobody believed her for a few 492 00:22:29,150 --> 00:22:27,180 years because this was such a radical 493 00:22:32,060 --> 00:22:29,160 idea but eventually people came to 494 00:22:33,590 --> 00:22:32,070 realize that she was right after some of 495 00:22:35,780 --> 00:22:33,600 her most important discovery she began 496 00:22:39,140 --> 00:22:35,790 to write about science and astronomy for 497 00:22:40,910 --> 00:22:39,150 public audiences here in 1952 she said 498 00:22:43,700 --> 00:22:40,920 perhaps the nebula is in some way 499 00:22:45,680 --> 00:22:43,710 responsible for their very existence so 500 00:22:48,500 --> 00:22:45,690 people were beginning to figure out that 501 00:22:50,240 --> 00:22:48,510 maybe stars formed from nebulae and this 502 00:22:52,370 --> 00:22:50,250 is one of the earliest photographs of 503 00:22:54,380 --> 00:22:52,380 the Orion Nebula so you can see there 504 00:22:58,430 --> 00:22:54,390 are several stars that are potentially 505 00:23:00,890 --> 00:22:58,440 embedded in that nebula it all came 506 00:23:03,200 --> 00:23:00,900 together when two astronomers were able 507 00:23:06,020 --> 00:23:03,210 to make sense of it all so on the left 508 00:23:07,880 --> 00:23:06,030 here is Victor and Barsoomian he was an 509 00:23:09,350 --> 00:23:07,890 armenian astronomer which meant that at 510 00:23:09,800 --> 00:23:09,360 the time he was working in the soviet 511 00:23:13,880 --> 00:23:09,810 union 512 00:23:15,700 --> 00:23:13,890 had a pretty limited understanding of 513 00:23:18,680 --> 00:23:15,710 the science that was going on there and 514 00:23:21,290 --> 00:23:18,690 then independently george herbert who 515 00:23:25,250 --> 00:23:21,300 was on the faculty at the university of 516 00:23:29,060 --> 00:23:25,260 hawaii both argued that t-tauri stars 517 00:23:31,190 --> 00:23:29,070 must be young they are clustered here's 518 00:23:35,690 --> 00:23:31,200 a cluster of many many t-tauri stars 519 00:23:37,040 --> 00:23:35,700 it's a Hubble image of NGC 3603 and not 520 00:23:39,430 --> 00:23:37,050 only are they clustered but they're 521 00:23:41,870 --> 00:23:39,440 embedded in these clouds of gas and dust 522 00:23:43,730 --> 00:23:41,880 so these are signs that these are young 523 00:23:47,620 --> 00:23:43,740 stars that they have formed from the 524 00:23:50,330 --> 00:23:47,630 nebula itself and this was 525 00:23:52,880 --> 00:23:50,340 philosophically an important advance in 526 00:23:55,460 --> 00:23:52,890 the thinking of astronomers for 527 00:23:57,500 --> 00:23:55,470 millennia people had imagined that the 528 00:23:59,960 --> 00:23:57,510 universe had all come together and was 529 00:24:02,420 --> 00:23:59,970 formed sometime in the distant past and 530 00:24:04,550 --> 00:24:02,430 humanity showed up and it was our job to 531 00:24:07,820 --> 00:24:04,560 figure out what was already there but 532 00:24:10,190 --> 00:24:07,830 this was one of the first signs that the 533 00:24:10,600 --> 00:24:10,200 cosmos was still in the act of forming 534 00:24:13,480 --> 00:24:10,610 its 535 00:24:16,240 --> 00:24:13,490 that new objects and new potential 536 00:24:18,360 --> 00:24:16,250 places were continuing to form out of 537 00:24:23,320 --> 00:24:18,370 the original materials of the universe 538 00:24:25,299 --> 00:24:23,330 so we are in an evolving universe today 539 00:24:28,000 --> 00:24:25,309 we know of thousands of young stars in 540 00:24:30,310 --> 00:24:28,010 various star forming regions here's the 541 00:24:33,039 --> 00:24:30,320 Orion Nebula and then these are some 542 00:24:34,930 --> 00:24:33,049 other star forming regions in our galaxy 543 00:24:43,330 --> 00:24:34,940 where you can see these young stars 544 00:24:45,460 --> 00:24:43,340 forming from gas and dust clouds now 545 00:24:49,419 --> 00:24:45,470 this is our conceptual picture of how 546 00:24:51,370 --> 00:24:49,429 these stars form you have these huge 547 00:24:54,539 --> 00:24:51,380 clouds of gas and dust that can give 548 00:24:58,120 --> 00:24:54,549 birth to thousands of solar systems and 549 00:24:59,950 --> 00:24:58,130 in small regions of those clouds you 550 00:25:02,530 --> 00:24:59,960 might have just enough material that the 551 00:25:04,530 --> 00:25:02,540 gravity of that material is powerful 552 00:25:07,930 --> 00:25:04,540 enough to cause it to start collapsing 553 00:25:10,570 --> 00:25:07,940 so early on you have a dusty envelope 554 00:25:13,380 --> 00:25:10,580 that's collapsing and becoming more and 555 00:25:17,470 --> 00:25:13,390 more dense and hotter at its center 556 00:25:20,310 --> 00:25:17,480 after about 150,000 years most of that 557 00:25:22,720 --> 00:25:20,320 envelope has formed into a central star 558 00:25:25,750 --> 00:25:22,730 but the material doesn't just fall 559 00:25:27,520 --> 00:25:25,760 directly onto the star these cores are 560 00:25:29,560 --> 00:25:27,530 spinning very slowly and anything that 561 00:25:32,680 --> 00:25:29,570 spins as it falls in word instead of 562 00:25:36,250 --> 00:25:32,690 forming just a central sphere it's gonna 563 00:25:40,030 --> 00:25:36,260 first form a disk so this disk forms and 564 00:25:41,560 --> 00:25:40,040 it progresses to feed onto the star so 565 00:25:44,260 --> 00:25:41,570 for a few hundred thousand years you 566 00:25:46,240 --> 00:25:44,270 have a star with a disk kind of a 567 00:25:48,130 --> 00:25:46,250 remnant remnant envelope still falling 568 00:25:49,780 --> 00:25:48,140 onto the disk and then some fraction of 569 00:25:53,169 --> 00:25:49,790 that material gets ejected from the 570 00:25:55,690 --> 00:25:53,179 poles of the stars carving out a cavity 571 00:25:57,850 --> 00:25:55,700 in the envelope and sometimes you can 572 00:26:01,150 --> 00:25:57,860 see some pretty dramatic outflows gas 573 00:26:03,280 --> 00:26:01,160 being launched from the star after about 574 00:26:04,810 --> 00:26:03,290 five hundred thousand years the envelope 575 00:26:07,060 --> 00:26:04,820 is gone and you're left with a disk 576 00:26:09,340 --> 00:26:07,070 orbiting the star and that disk may be 577 00:26:11,620 --> 00:26:09,350 forming planets that's a really hot 578 00:26:13,240 --> 00:26:11,630 topic of research right now how early in 579 00:26:15,610 --> 00:26:13,250 the formation of a star do you see 580 00:26:17,289 --> 00:26:15,620 planets and the signs are starting to 581 00:26:19,870 --> 00:26:17,299 point to planets forming almost as soon 582 00:26:22,090 --> 00:26:19,880 as the star does there's a lot of debate 583 00:26:23,379 --> 00:26:22,100 if you see gaps in a disc does that 584 00:26:25,419 --> 00:26:23,389 necessarily mean there's 585 00:26:28,659 --> 00:26:25,429 planet there or could some other process 586 00:26:30,009 --> 00:26:28,669 be giving the signposts of planets after 587 00:26:32,049 --> 00:26:30,019 about two million years 588 00:26:34,509 --> 00:26:32,059 plus or minus a million years it varies 589 00:26:36,810 --> 00:26:34,519 a lot from system to system that disk is 590 00:26:39,339 --> 00:26:36,820 gone and you're left with planets 591 00:26:41,859 --> 00:26:39,349 orbiting the star and this is a very 592 00:26:47,349 --> 00:26:41,869 stable situation in many cases it lasts 593 00:26:49,810 --> 00:26:47,359 for billions of years now where are 594 00:26:51,549 --> 00:26:49,820 stars forming in our galaxy this is an 595 00:26:53,079 --> 00:26:51,559 artist's rendition of the Milky Way by 596 00:26:56,799 --> 00:26:53,089 Robert heard at the Spitzer Science 597 00:26:58,749 --> 00:26:56,809 Center and you can see the sort of dense 598 00:27:01,839 --> 00:26:58,759 central bulge of our galaxy and the 599 00:27:04,269 --> 00:27:01,849 spiral arms the stars are forming in the 600 00:27:06,339 --> 00:27:04,279 coldest parts of the galaxy you can see 601 00:27:08,979 --> 00:27:06,349 these little brown clouds here these are 602 00:27:10,749 --> 00:27:08,989 cold molecular clouds they're so cold 603 00:27:12,909 --> 00:27:10,759 that the gas forms in the moist 604 00:27:16,509 --> 00:27:12,919 remains in a molecular State instead of 605 00:27:18,219 --> 00:27:16,519 an atomic form so they're cold and dense 606 00:27:19,599 --> 00:27:18,229 and they start collapsing like I was 607 00:27:24,219 --> 00:27:19,609 showing you in the previous slide to 608 00:27:26,199 --> 00:27:24,229 form these new stars to really study 609 00:27:28,690 --> 00:27:26,209 where the stars are though we have to 610 00:27:31,419 --> 00:27:28,700 use more than just the light that meets 611 00:27:34,089 --> 00:27:31,429 our eyes so a star formation is really a 612 00:27:36,190 --> 00:27:34,099 challenge for multi-wavelength astronomy 613 00:27:39,069 --> 00:27:36,200 where we're using not just visible light 614 00:27:41,649 --> 00:27:39,079 but ultraviolet light infrared light 615 00:27:43,889 --> 00:27:41,659 radio waves all these different 616 00:27:46,599 --> 00:27:43,899 wavelengths of light that can reach us 617 00:27:49,690 --> 00:27:46,609 the best way to map the large-scale 618 00:27:51,999 --> 00:27:49,700 distribution of gas to form stars is by 619 00:27:54,249 --> 00:27:52,009 doing radio astronomy this is the five 620 00:27:56,379 --> 00:27:54,259 College Radio Astronomy Observatory it 621 00:27:58,749 --> 00:27:56,389 no longer exists but it was on a 622 00:28:00,759 --> 00:27:58,759 peninsula in western Massachusetts that 623 00:28:01,659 --> 00:28:00,769 extends into the Quabbin Reservoir it 624 00:28:03,940 --> 00:28:01,669 reached the end of its scientific 625 00:28:05,709 --> 00:28:03,950 lifetime and this is kind of a natural 626 00:28:07,599 --> 00:28:05,719 preserve so the agreement was they had 627 00:28:09,549 --> 00:28:07,609 to disassemble the radio telescope after 628 00:28:12,459 --> 00:28:09,559 they were done doing science with it but 629 00:28:14,829 --> 00:28:12,469 this is an image it made of carbon 630 00:28:17,560 --> 00:28:14,839 monoxide gas in the torah' star-forming 631 00:28:20,259 --> 00:28:17,570 region carbon monoxide is far from the 632 00:28:22,539 --> 00:28:20,269 most common component of these molecular 633 00:28:24,789 --> 00:28:22,549 clouds it's mostly hydrogen molecular 634 00:28:26,769 --> 00:28:24,799 hydrogen but carbon monoxide is really 635 00:28:28,479 --> 00:28:26,779 easy to detect so we're going to map a 636 00:28:31,329 --> 00:28:28,489 star-forming region that's that's a good 637 00:28:33,430 --> 00:28:31,339 way to go and you can see in this image 638 00:28:37,330 --> 00:28:33,440 this filamentary structure these long 639 00:28:40,030 --> 00:28:37,340 sort of trails of gas that's 640 00:28:42,460 --> 00:28:40,040 to a radio telescope and these trails 641 00:28:44,470 --> 00:28:42,470 are where you call or they're called 642 00:28:46,630 --> 00:28:44,480 filaments and these are the dense 643 00:28:51,640 --> 00:28:46,640 regions that are likely to form stars in 644 00:28:53,170 --> 00:28:51,650 fact are forming stars and torez I'm 645 00:28:55,800 --> 00:28:53,180 going to be telling you mostly about 646 00:28:58,150 --> 00:28:55,810 what you can do with infrared astronomy 647 00:29:01,060 --> 00:28:58,160 there's an inner multi-wavelength study 648 00:29:02,980 --> 00:29:01,070 of star formation this is Barnard dark 649 00:29:05,080 --> 00:29:02,990 cloud 68 and you can tell why it's 650 00:29:07,900 --> 00:29:05,090 called a dark cloud it's it's a cloud 651 00:29:10,480 --> 00:29:07,910 and it's dark you can see how this is a 652 00:29:14,050 --> 00:29:10,490 very dense star field but around the 653 00:29:16,900 --> 00:29:14,060 cloud you see some reddened stars around 654 00:29:19,750 --> 00:29:16,910 its edges and the center almost nothing 655 00:29:22,900 --> 00:29:19,760 pops out this is a visible light image 656 00:29:26,320 --> 00:29:22,910 if we look in the infrared it's a very 657 00:29:29,620 --> 00:29:26,330 different situation this is an infrared 658 00:29:32,200 --> 00:29:29,630 image and suddenly we see hundreds of 659 00:29:34,480 --> 00:29:32,210 stars poking through the cloud the 660 00:29:38,200 --> 00:29:34,490 advantage to infrared light is that it 661 00:29:40,180 --> 00:29:38,210 lets us see through the dust the 662 00:29:42,490 --> 00:29:40,190 infrared light escapes more easily 663 00:29:44,970 --> 00:29:42,500 through this dust and it's also 664 00:29:47,290 --> 00:29:44,980 sensitive to objects that aren't hot 665 00:29:48,760 --> 00:29:47,300 astronomers tend to play fast and loose 666 00:29:50,260 --> 00:29:48,770 with their temperature words we'll talk 667 00:29:53,410 --> 00:29:50,270 about cool things that are actually 668 00:29:55,180 --> 00:29:53,420 hundreds of degrees but this infrared 669 00:29:58,210 --> 00:29:55,190 light is really sensitive to things that 670 00:29:59,680 --> 00:29:58,220 aren't as hot as stars yet they 671 00:30:01,690 --> 00:29:59,690 eventually will be but they're there 672 00:30:03,190 --> 00:30:01,700 from a few hundred to a few thousand 673 00:30:08,500 --> 00:30:03,200 degrees that's where the infrared is 674 00:30:11,080 --> 00:30:08,510 really most useful here's a Ryan in 675 00:30:13,990 --> 00:30:11,090 visible light the famous constellation 676 00:30:16,090 --> 00:30:14,000 the three stars in the belt Betelgeuse 677 00:30:19,030 --> 00:30:16,100 is a red supergiant and the shoulder of 678 00:30:21,370 --> 00:30:19,040 Orion Rigel is a blue supergiant down 679 00:30:23,470 --> 00:30:21,380 here it is me and you have a sword 680 00:30:27,490 --> 00:30:23,480 hanging from the belt the Orion Nebula 681 00:30:31,120 --> 00:30:27,500 is this faint fuzzy patch here and so 682 00:30:34,180 --> 00:30:31,130 visible light detects stars that here's 683 00:30:37,390 --> 00:30:34,190 Orion in the infrared the picture I 684 00:30:39,190 --> 00:30:37,400 showed you at the beginning you don't 685 00:30:40,750 --> 00:30:39,200 really see many stars in this one 686 00:30:43,000 --> 00:30:40,760 Betelgeuse because it's such a bright 687 00:30:47,140 --> 00:30:43,010 red star still pops out in the infrared 688 00:30:50,960 --> 00:30:47,150 image but Rigel and the belt stars are 689 00:30:52,760 --> 00:30:50,970 totally absent and you see these bright 690 00:30:55,070 --> 00:30:52,770 regions where the stars are forming the 691 00:30:57,140 --> 00:30:55,080 Orion Nebula is now the brightest thing 692 00:30:59,630 --> 00:30:57,150 in the image and you can see that in 693 00:31:01,700 --> 00:30:59,640 Orion you have these bright star-forming 694 00:31:02,870 --> 00:31:01,710 regions extending kind of all up and 695 00:31:06,140 --> 00:31:02,880 down the southern half of the 696 00:31:07,760 --> 00:31:06,150 constellation so the infrared is really 697 00:31:14,270 --> 00:31:07,770 the key to telling us where the stars 698 00:31:15,289 --> 00:31:14,280 are forming and why is a Ryan so 699 00:31:18,020 --> 00:31:15,299 important from a star-forming 700 00:31:20,870 --> 00:31:18,030 perspective we have thousands of young 701 00:31:22,549 --> 00:31:20,880 stars in the Orion Nebula alone but it's 702 00:31:26,720 --> 00:31:22,559 really just the centerpiece of this huge 703 00:31:29,810 --> 00:31:26,730 star forming complex if you were to draw 704 00:31:32,029 --> 00:31:29,820 a circle around our solar system that 705 00:31:34,460 --> 00:31:32,039 was about fifteen hundred light years in 706 00:31:37,060 --> 00:31:34,470 radius encompassing many of the nearby 707 00:31:39,529 --> 00:31:37,070 stars that we are all familiar to us 708 00:31:43,640 --> 00:31:39,539 Orion contains more than half of the 709 00:31:45,919 --> 00:31:43,650 young forming stars in that region it's 710 00:31:48,049 --> 00:31:45,929 the nearest place where the most massive 711 00:31:50,149 --> 00:31:48,059 stars are forming so you really see the 712 00:31:53,299 --> 00:31:50,159 full spectrum of stellar masses forming 713 00:31:55,250 --> 00:31:53,309 an Orion and we can also probe a lot of 714 00:31:58,460 --> 00:31:55,260 different star forming environments in 715 00:32:01,130 --> 00:31:58,470 Orion on the left is one of these 716 00:32:02,899 --> 00:32:01,140 Barnard dark clouds this is not an Orion 717 00:32:05,659 --> 00:32:02,909 but it's just an example of isolated 718 00:32:09,529 --> 00:32:05,669 star forming you have this really dense 719 00:32:11,840 --> 00:32:09,539 field of advanced more more aged older 720 00:32:14,630 --> 00:32:11,850 stars and then this dark cloud that 721 00:32:19,970 --> 00:32:14,640 contains maybe one or a few forming 722 00:32:23,539 --> 00:32:19,980 stars here is part of Orion OMC 2 3 is 723 00:32:25,460 --> 00:32:23,549 the Orion molecular cloud 2/3 it's just 724 00:32:27,260 --> 00:32:25,470 a part of the Orion molecular clouds and 725 00:32:30,320 --> 00:32:27,270 this is an example of clustered star 726 00:32:33,560 --> 00:32:30,330 formation you can see these dark dusty 727 00:32:35,720 --> 00:32:33,570 filaments with young stars all along 728 00:32:37,909 --> 00:32:35,730 them so in Orion we can really get a 729 00:32:42,470 --> 00:32:37,919 sense for how stars interact with one 730 00:32:44,840 --> 00:32:42,480 another as they form there are even 731 00:32:47,510 --> 00:32:44,850 different environments within Orion this 732 00:32:49,399 --> 00:32:47,520 is a map of coal dust in Orion going 733 00:32:52,610 --> 00:32:49,409 from the Orion Nebula far to the south 734 00:32:54,799 --> 00:32:52,620 and then these are in sets where we zoom 735 00:32:57,310 --> 00:32:54,809 in on a couple of these regions and look 736 00:33:00,440 --> 00:32:57,320 at how stars are distributed in them 737 00:33:02,450 --> 00:33:00,450 this is a very densely populated star 738 00:33:04,409 --> 00:33:02,460 forming region within Orion that you 739 00:33:06,149 --> 00:33:04,419 might think of as a city all 740 00:33:08,369 --> 00:33:06,159 these circles mark the locations of 741 00:33:10,289 --> 00:33:08,379 young stars what we call protostars 742 00:33:12,149 --> 00:33:10,299 and the size of the circle tells you how 743 00:33:15,269 --> 00:33:12,159 luminous it is how bright it is how much 744 00:33:18,149 --> 00:33:15,279 light it's giving off so in this part of 745 00:33:20,999 --> 00:33:18,159 Orion you have very dense clusters of 746 00:33:23,340 --> 00:33:21,009 stars that are quite luminous and all 747 00:33:24,690 --> 00:33:23,350 interacting with one another farther to 748 00:33:26,970 --> 00:33:24,700 the south we have what you might think 749 00:33:29,639 --> 00:33:26,980 of as the suburbs where there are fewer 750 00:33:31,950 --> 00:33:29,649 stars there's fewer back there's less 751 00:33:34,979 --> 00:33:31,960 background emission from the from local 752 00:33:36,960 --> 00:33:34,989 gas and dust the stars are less luminous 753 00:33:39,359 --> 00:33:36,970 and there's a little bit less going on 754 00:33:41,700 --> 00:33:39,369 there so it really is sort of an 755 00:33:48,180 --> 00:33:41,710 experimental lab to see how stars form 756 00:33:49,320 --> 00:33:48,190 in different environments so I'm going 757 00:33:51,509 --> 00:33:49,330 to tell you about how we've used 758 00:33:54,060 --> 00:33:51,519 different space telescopes to understand 759 00:33:57,119 --> 00:33:54,070 star formation in Orion and it begins 760 00:33:59,430 --> 00:33:57,129 with the spitzer space telescope this is 761 00:34:02,070 --> 00:33:59,440 a point eight five meter telescope not 762 00:34:05,009 --> 00:34:02,080 huge compared to a few of the ones we'll 763 00:34:08,159 --> 00:34:05,019 be discussing it launched in 2003 and 764 00:34:09,750 --> 00:34:08,169 these infrared space telescopes they 765 00:34:12,000 --> 00:34:09,760 have to be cooled to be most effective 766 00:34:13,799 --> 00:34:12,010 they're about the same temperature as 767 00:34:15,720 --> 00:34:13,809 the objects they're trying to detect so 768 00:34:18,539 --> 00:34:15,730 if you don't cool them they're going to 769 00:34:20,250 --> 00:34:18,549 detect themselves to put it simply so 770 00:34:21,960 --> 00:34:20,260 you have to cool them down and you do 771 00:34:23,879 --> 00:34:21,970 that by putting some kind of substance 772 00:34:27,000 --> 00:34:23,889 aboard some kind of cryogen to keep it 773 00:34:28,980 --> 00:34:27,010 cold cryogen loses its effectiveness 774 00:34:32,059 --> 00:34:28,990 after a while so spitzer launched in 775 00:34:34,710 --> 00:34:32,069 2003 but it ran out of cryogen in 2009 776 00:34:36,240 --> 00:34:34,720 it's still effective at some level it 777 00:34:40,169 --> 00:34:36,250 has limited capabilities and it's 778 00:34:42,059 --> 00:34:40,179 continuing to send back data and it's in 779 00:34:43,859 --> 00:34:42,069 an earth trailing orbit this is 780 00:34:47,730 --> 00:34:43,869 approximately where it was when I put 781 00:34:49,260 --> 00:34:47,740 the slide together it's about the same 782 00:34:51,030 --> 00:34:49,270 distance from the Sun as Earth but just 783 00:34:53,220 --> 00:34:51,040 a little farther out so it orbits a 784 00:34:55,230 --> 00:34:53,230 little bit more slowly and it loses 785 00:34:56,579 --> 00:34:55,240 ground on earth as each year goes by so 786 00:34:58,170 --> 00:34:56,589 that's another thing that's limiting its 787 00:34:59,520 --> 00:34:58,180 capabilities is it's farther from Earth 788 00:35:01,530 --> 00:34:59,530 it becomes more difficult to communicate 789 00:35:04,410 --> 00:35:01,540 with it but it's been a very productive 790 00:35:09,000 --> 00:35:04,420 Space Telescope so far and we used it to 791 00:35:12,120 --> 00:35:09,010 survey Oh Ryan this is a Spitzer map of 792 00:35:14,309 --> 00:35:12,130 part of the Orion Molecular clouds you 793 00:35:17,730 --> 00:35:14,319 can see all of this bright gaseous 794 00:35:20,460 --> 00:35:17,740 material dark dusty lanes 795 00:35:22,800 --> 00:35:20,470 and young stars that are forming this 796 00:35:24,870 --> 00:35:22,810 schematic gives you a sense for why and 797 00:35:29,670 --> 00:35:24,880 infrared telescope is good at detecting 798 00:35:32,310 --> 00:35:29,680 young stars a plain old star it's light 799 00:35:33,990 --> 00:35:32,320 output peaks at wavelengths that we can 800 00:35:36,780 --> 00:35:34,000 detect with our eye is it visible or 801 00:35:38,790 --> 00:35:36,790 optical wavelengths and then it's light 802 00:35:40,350 --> 00:35:38,800 distribution falls off pretty rapidly as 803 00:35:43,740 --> 00:35:40,360 you go into the infrared the longer 804 00:35:46,080 --> 00:35:43,750 wavelengths but if you have a disc of 805 00:35:49,260 --> 00:35:46,090 relatively cool dust around the star 806 00:35:52,320 --> 00:35:49,270 that's bright in the infrared so instead 807 00:35:54,120 --> 00:35:52,330 of your basic star the spectrum of the 808 00:35:55,890 --> 00:35:54,130 star it's energy distribution falls off 809 00:35:58,859 --> 00:35:55,900 a lot more slowly through the infrared 810 00:36:01,890 --> 00:35:58,869 and thus infrared Space Telescope's are 811 00:36:04,050 --> 00:36:01,900 really good at picking these out so we 812 00:36:05,190 --> 00:36:04,060 can see the real-life equivalents of 813 00:36:07,500 --> 00:36:05,200 these cartoons I showed you earlier 814 00:36:09,359 --> 00:36:07,510 where you have the very young protostars 815 00:36:12,000 --> 00:36:09,369 where there's an envelope falling onto a 816 00:36:14,280 --> 00:36:12,010 disc and then the slightly more advanced 817 00:36:19,830 --> 00:36:14,290 young stars where much most of the 818 00:36:22,770 --> 00:36:19,840 envelope has been cleared away once we 819 00:36:24,830 --> 00:36:22,780 identified all these young stars with 820 00:36:28,500 --> 00:36:24,840 Spitzer we continued with Herschel 821 00:36:30,480 --> 00:36:28,510 Herschel was primarily funded by the 822 00:36:34,170 --> 00:36:30,490 European Space Agency but it also had 823 00:36:36,330 --> 00:36:34,180 contributions from NASA it's a big one 824 00:36:38,130 --> 00:36:36,340 three and a half meters in diameter its 825 00:36:40,410 --> 00:36:38,140 primary mirror and it operated in the 826 00:36:42,210 --> 00:36:40,420 far infrared so Spitzer was sort of mid 827 00:36:46,170 --> 00:36:42,220 infrared Herschel is even longer 828 00:36:49,320 --> 00:36:46,180 wavelengths it launched in 2009 ran out 829 00:36:51,810 --> 00:36:49,330 of cryogen in 2013 and all of Herschel's 830 00:36:54,150 --> 00:36:51,820 instruments required higher cryogen to 831 00:36:56,880 --> 00:36:54,160 operate so it's no longer you know 832 00:37:00,240 --> 00:36:56,890 producing images for us it is at a 833 00:37:03,990 --> 00:37:00,250 special point in space called l2 the 834 00:37:05,730 --> 00:37:04,000 second lagrangian point at l2 the 835 00:37:07,890 --> 00:37:05,740 Earth's gravity and the sun's gravity 836 00:37:10,020 --> 00:37:07,900 balance out so you get a stable orbit 837 00:37:13,859 --> 00:37:10,030 even though you're kind of far away from 838 00:37:16,320 --> 00:37:13,869 Earth in fact the l2 point is four times 839 00:37:19,410 --> 00:37:16,330 farther away than the moon it's really 840 00:37:21,540 --> 00:37:19,420 out there so unlike a telescope at low 841 00:37:23,240 --> 00:37:21,550 Earth orbit you can't go out to l2 and 842 00:37:26,220 --> 00:37:23,250 fix things at least not yet 843 00:37:28,620 --> 00:37:26,230 so after Herschel's life cycle was over 844 00:37:30,240 --> 00:37:28,630 that was the end of its science but l2 845 00:37:31,620 --> 00:37:30,250 is a great place to put a foreign for a 846 00:37:34,920 --> 00:37:31,630 telescope it's a stable 847 00:37:36,270 --> 00:37:34,930 orbit and things are also cold there so 848 00:37:38,610 --> 00:37:36,280 you really get a great view of the 849 00:37:40,080 --> 00:37:38,620 infrared sky from l2 and it's not the 850 00:37:41,850 --> 00:37:40,090 only telescope that's currently there 851 00:37:46,620 --> 00:37:41,860 are not additional ones you're going to 852 00:37:48,480 --> 00:37:46,630 join it how mention that later on the 853 00:37:50,850 --> 00:37:48,490 advantage to Herschel is that we could 854 00:37:53,430 --> 00:37:50,860 follow up on these protostars that 855 00:37:55,800 --> 00:37:53,440 Spitzer had identified we conducted hops 856 00:37:57,720 --> 00:37:55,810 that's the Herschel Orion protostar 857 00:37:59,490 --> 00:37:57,730 Survey these are some members of the 858 00:38:02,610 --> 00:37:59,500 hops team one of our meetings in Granada 859 00:38:05,130 --> 00:38:02,620 Spain a few years ago with Spitzer we 860 00:38:06,630 --> 00:38:05,140 found more than 500 of these protostars 861 00:38:08,160 --> 00:38:06,640 these are young stars with the dusty 862 00:38:11,220 --> 00:38:08,170 envelopes that are just beginning to 863 00:38:13,620 --> 00:38:11,230 form and then we follow it up on more 864 00:38:16,260 --> 00:38:13,630 than 300 of them with Herschel so this 865 00:38:20,130 --> 00:38:16,270 map the dark shading tells you where the 866 00:38:22,470 --> 00:38:20,140 where that dust is in Orion all up and 867 00:38:24,840 --> 00:38:22,480 down the Orion molecular clouds the 868 00:38:27,300 --> 00:38:24,850 Orion Nebula is here and then these 869 00:38:29,640 --> 00:38:27,310 circles mark the locations of protostars 870 00:38:31,140 --> 00:38:29,650 that we followed up with Herschel all 871 00:38:32,940 --> 00:38:31,150 these little thumbnails here are 872 00:38:35,300 --> 00:38:32,950 actually Spitzer images they give you a 873 00:38:38,070 --> 00:38:35,310 sense for the environment whether it's 874 00:38:40,710 --> 00:38:38,080 crowded with bright backgrounds or maybe 875 00:38:43,350 --> 00:38:40,720 somewhat less crowded with with a dim 876 00:38:47,070 --> 00:38:43,360 background going from the city out to 877 00:38:50,190 --> 00:38:47,080 the suburbs so we did all this follow up 878 00:38:52,470 --> 00:38:50,200 with Herschel and this really gives you 879 00:38:54,990 --> 00:38:52,480 a sense comparing Spitzer data on the 880 00:38:56,400 --> 00:38:55,000 left to the combination of Spitzer and 881 00:38:58,340 --> 00:38:56,410 Herschel on the right this shows you 882 00:39:01,290 --> 00:38:58,350 what you can do with the far infrared 883 00:39:03,870 --> 00:39:01,300 Spitzer the dustiest regions in the 884 00:39:05,550 --> 00:39:03,880 cloud are dark they're cold they're not 885 00:39:07,530 --> 00:39:05,560 really emitting very much at the mid wid 886 00:39:09,780 --> 00:39:07,540 mid infrared wavelengths that Spitzer 887 00:39:11,790 --> 00:39:09,790 detects so you have these dark dust 888 00:39:13,920 --> 00:39:11,800 lanes and then you can tell where the 889 00:39:16,230 --> 00:39:13,930 stars are but they're really deeply 890 00:39:17,840 --> 00:39:16,240 embedded young ones you can't learn very 891 00:39:21,180 --> 00:39:17,850 much about them because they're faint 892 00:39:22,890 --> 00:39:21,190 here the blue is from Spitzer but then 893 00:39:25,110 --> 00:39:22,900 the red and yellow we're bringing in the 894 00:39:27,060 --> 00:39:25,120 Herschel data so there are two things to 895 00:39:29,250 --> 00:39:27,070 notice here first of all some of these 896 00:39:30,990 --> 00:39:29,260 faint protostars in the spitzer image 897 00:39:32,970 --> 00:39:31,000 are now some of the brightest ones in 898 00:39:35,190 --> 00:39:32,980 Herschel there are two here there's one 899 00:39:37,110 --> 00:39:35,200 up here these really bright Herschel 900 00:39:38,820 --> 00:39:37,120 protostars those are the really young 901 00:39:41,460 --> 00:39:38,830 ones those are the ones we can study to 902 00:39:43,290 --> 00:39:41,470 learn exactly what's going on as gas and 903 00:39:45,410 --> 00:39:43,300 dust begins to condense from the 904 00:39:48,450 --> 00:39:45,420 molecular cloud to forms 905 00:39:51,540 --> 00:39:48,460 the other thing to notice here is that 906 00:39:54,450 --> 00:39:51,550 the dark dust lanes are now glowing at 907 00:39:56,550 --> 00:39:54,460 the longest far infrared wavelengths you 908 00:39:58,740 --> 00:39:56,560 can really see where the dust is and see 909 00:40:00,990 --> 00:39:58,750 how intense and how much dust there is 910 00:40:02,400 --> 00:40:01,000 by how brightly it's glowing so this 911 00:40:04,050 --> 00:40:02,410 really allows us to understand 912 00:40:06,210 --> 00:40:04,060 everything that's going on in a 913 00:40:08,010 --> 00:40:06,220 star-forming region when we combine the 914 00:40:12,240 --> 00:40:08,020 mid infrared and the farm for headlight 915 00:40:14,210 --> 00:40:12,250 from Herschel I'm going to tell you 916 00:40:17,160 --> 00:40:14,220 about one of our first hops results 917 00:40:19,860 --> 00:40:17,170 we're going to go back in time from the 918 00:40:21,990 --> 00:40:19,870 Herschel Space Telescope to Herschel the 919 00:40:23,610 --> 00:40:22,000 astronomers William Herschel and 920 00:40:27,560 --> 00:40:23,620 Caroline Herschel they're shown in this 921 00:40:30,540 --> 00:40:27,570 painting here they were some of the best 922 00:40:34,470 --> 00:40:30,550 astronomers of their time working in the 923 00:40:36,660 --> 00:40:34,480 18th century and William Herschel was 924 00:40:40,170 --> 00:40:36,670 conducting a survey with his telescope 925 00:40:43,440 --> 00:40:40,180 of the Milky Way and he discovered dark 926 00:40:45,150 --> 00:40:43,450 patches and he said he spoke German but 927 00:40:46,890 --> 00:40:45,160 what he said was truly there is a hole 928 00:40:49,710 --> 00:40:46,900 in the sky here when he saw these dark 929 00:40:51,180 --> 00:40:49,720 patches this is one of the dark patches 930 00:40:54,210 --> 00:40:51,190 that he talked about this is what we 931 00:40:56,640 --> 00:40:54,220 today call NGC 1999 932 00:40:58,770 --> 00:40:56,650 this is our first Herschel image we 933 00:41:01,260 --> 00:40:58,780 bring in some Kitt Peak data that's in 934 00:41:03,780 --> 00:41:01,270 blue for context that's a that's optical 935 00:41:06,060 --> 00:41:03,790 possibly near infrared imaging we see 936 00:41:07,980 --> 00:41:06,070 some of our Herschel protostars here and 937 00:41:12,390 --> 00:41:07,990 then this is a Hubble close-up of this 938 00:41:16,670 --> 00:41:12,400 NGC 1999 region it's one of these holes 939 00:41:22,260 --> 00:41:20,040 it turned out that Herschel's holes in 940 00:41:24,000 --> 00:41:22,270 the sky are mostly these dark dust 941 00:41:28,320 --> 00:41:24,010 clouds like we were talking about before 942 00:41:30,150 --> 00:41:28,330 this is NGC 1999 this is Barnard 68 that 943 00:41:33,420 --> 00:41:30,160 I showed you before where the dark cloud 944 00:41:35,190 --> 00:41:33,430 is it's not a hole it's a dark dusty 945 00:41:40,110 --> 00:41:35,200 cloud and when you look in the infrared 946 00:41:43,590 --> 00:41:40,120 you see lots of stars here but in this 947 00:41:45,630 --> 00:41:43,600 particular case NGC 1999 it's a little 948 00:41:46,860 --> 00:41:45,640 bit different this is the Hubble image I 949 00:41:50,640 --> 00:41:46,870 showed you but then when you look at 950 00:41:53,070 --> 00:41:50,650 Herschel images in the far infrared the 951 00:41:54,720 --> 00:41:53,080 hole in the sky is still a hole if there 952 00:41:57,570 --> 00:41:54,730 were dust here it would start to glow in 953 00:41:58,840 --> 00:41:57,580 the far infrared when we go even further 954 00:42:03,310 --> 00:41:58,850 out into the infer 955 00:42:06,010 --> 00:42:03,320 it's still dark so there's no dust there 956 00:42:08,440 --> 00:42:06,020 it would glow and here in this very deep 957 00:42:12,730 --> 00:42:08,450 near infrared image we see a star 958 00:42:15,340 --> 00:42:12,740 through this hole in the nebula that's 959 00:42:18,370 --> 00:42:15,350 not particularly red so we're actually 960 00:42:21,130 --> 00:42:18,380 seeing through empty space here this one 961 00:42:22,720 --> 00:42:21,140 really is a hole in the sky so it was 962 00:42:24,340 --> 00:42:22,730 kind of a kind of a neat discovery we 963 00:42:26,830 --> 00:42:24,350 made Herschel the astronomer said 964 00:42:29,830 --> 00:42:26,840 something in 1774 truly there was a hole 965 00:42:31,630 --> 00:42:29,840 in the sky here 236 years later the 966 00:42:37,120 --> 00:42:31,640 telescope named after him confirmed that 967 00:42:39,420 --> 00:42:37,130 he was right about this one and this was 968 00:42:42,340 --> 00:42:39,430 the beginning of our of our hops project 969 00:42:44,980 --> 00:42:42,350 another really key discovery with hops 970 00:42:49,210 --> 00:42:44,990 is that there were proto stars in Orion 971 00:42:51,250 --> 00:42:49,220 that Spitzer missed they were too faint 972 00:42:53,500 --> 00:42:51,260 in the Spitzer images for people to 973 00:42:55,690 --> 00:42:53,510 realize that they were protostars so 974 00:42:57,400 --> 00:42:55,700 this is these are some thumbnails of two 975 00:43:00,430 --> 00:42:57,410 of these protostars the top row our 976 00:43:02,860 --> 00:43:00,440 Spitzer images this is kind of the near 977 00:43:04,510 --> 00:43:02,870 to mid infrared wavelengths that are a 978 00:43:06,640 --> 00:43:04,520 little bit longer than our eyes can 979 00:43:08,590 --> 00:43:06,650 detect and here in these two circles you 980 00:43:11,800 --> 00:43:08,600 see a faint object here and a brighter 981 00:43:13,480 --> 00:43:11,810 object here if you go out to some of the 982 00:43:16,510 --> 00:43:13,490 longest wavelengths that Spitzer was 983 00:43:19,510 --> 00:43:16,520 able to effectively work at in Orion you 984 00:43:22,500 --> 00:43:19,520 see nothing in this top circle and just 985 00:43:24,790 --> 00:43:22,510 a very faint blob in this bottom circle 986 00:43:26,470 --> 00:43:24,800 we weren't sure what these were just 987 00:43:29,230 --> 00:43:26,480 based on this information alone they 988 00:43:31,720 --> 00:43:29,240 were classified as galaxies to the 989 00:43:33,040 --> 00:43:31,730 extent they were classified at all but 990 00:43:35,470 --> 00:43:33,050 when we looked at them with Herschel 991 00:43:37,510 --> 00:43:35,480 they really jumped out all of a sudden 992 00:43:40,450 --> 00:43:37,520 they're the brightest point sources in 993 00:43:42,670 --> 00:43:40,460 this field down here at the bottom we've 994 00:43:44,380 --> 00:43:42,680 gone out to submillimetre wavelengths 995 00:43:46,390 --> 00:43:44,390 this is almost in the radio at this 996 00:43:49,420 --> 00:43:46,400 point where we're detecting very cold 997 00:43:52,360 --> 00:43:49,430 dust and they remain bright there so 998 00:43:54,580 --> 00:43:52,370 this is a sign that Herschel was able to 999 00:43:56,980 --> 00:43:54,590 detect protostars that spits our mist 1000 00:43:58,900 --> 00:43:56,990 and because there's you have to look at 1001 00:44:00,430 --> 00:43:58,910 such long wavelengths to see them that 1002 00:44:01,960 --> 00:44:00,440 means they're among the coldest proto 1003 00:44:05,260 --> 00:44:01,970 stars in Orion and therefore the 1004 00:44:07,420 --> 00:44:05,270 youngest our estimates are that they may 1005 00:44:09,790 --> 00:44:07,430 have formerly 25,000 years and I say 1006 00:44:11,410 --> 00:44:09,800 only that seems like a long time if you 1007 00:44:12,039 --> 00:44:11,420 remember back I told you it takes on 1008 00:44:13,839 --> 00:44:12,049 average to 1009 00:44:15,370 --> 00:44:13,849 million years for a starter for twenty 1010 00:44:16,059 --> 00:44:15,380 five thousand years is a tiny fraction 1011 00:44:18,160 --> 00:44:16,069 of that 1012 00:44:20,319 --> 00:44:18,170 so Herschel really allowed us to 1013 00:44:22,029 --> 00:44:20,329 complete the census of protostars in 1014 00:44:27,009 --> 00:44:22,039 Orion and really see what was going on 1015 00:44:30,130 --> 00:44:27,019 in the very youngest systems this is a 1016 00:44:32,650 --> 00:44:30,140 larger scale image of spit of these new 1017 00:44:34,390 --> 00:44:32,660 protostars Spitzer is on the right and 1018 00:44:36,160 --> 00:44:34,400 again in these four circles these are 1019 00:44:37,539 --> 00:44:36,170 the two I showed you before there are a 1020 00:44:39,910 --> 00:44:37,549 couple more down here to the south 1021 00:44:41,410 --> 00:44:39,920 there's almost nothing in Spitzer but 1022 00:44:44,199 --> 00:44:41,420 when you bring in the Herschel far 1023 00:44:47,380 --> 00:44:44,209 infrared data and the apex submillimetre 1024 00:44:49,390 --> 00:44:47,390 data they're very bright so we can 1025 00:44:50,949 --> 00:44:49,400 really understand all of the secrets 1026 00:44:56,799 --> 00:44:50,959 that are ayan has to offer but you only 1027 00:44:59,469 --> 00:44:56,809 do the longest wavelengths now that the 1028 00:45:01,449 --> 00:44:59,479 Herschel project has been we've had all 1029 00:45:03,819 --> 00:45:01,459 of our Herschel data for a few years and 1030 00:45:05,469 --> 00:45:03,829 most of the science has come out there 1031 00:45:06,549 --> 00:45:05,479 are still a few papers lingering along 1032 00:45:09,069 --> 00:45:06,559 that we're trying to get into the 1033 00:45:10,870 --> 00:45:09,079 literature but we've turned to detailed 1034 00:45:14,289 --> 00:45:10,880 follow-up of some of these protostars 1035 00:45:15,999 --> 00:45:14,299 with Hubble for instance with Hubble 1036 00:45:17,979 --> 00:45:16,009 once we know the proto stars are there 1037 00:45:20,019 --> 00:45:17,989 we can zoom in on them and get very 1038 00:45:23,130 --> 00:45:20,029 high-resolution images compared to what 1039 00:45:25,329 --> 00:45:23,140 we can get with Spitzer or with Herschel 1040 00:45:28,509 --> 00:45:25,339 now Hubble has a lot of different 1041 00:45:30,249 --> 00:45:28,519 instruments I work on the cosmic origins 1042 00:45:32,410 --> 00:45:30,259 spectrograph which is optimized for the 1043 00:45:35,199 --> 00:45:32,420 ultraviolet but for science we tend to 1044 00:45:37,269 --> 00:45:35,209 use for prints the science of star 1045 00:45:38,799 --> 00:45:37,279 formation at least the sort of work that 1046 00:45:41,529 --> 00:45:38,809 we do we tend to use the near infrared 1047 00:45:42,630 --> 00:45:41,539 cameras on Hubble there's Nick Moss 1048 00:45:45,880 --> 00:45:42,640 which was an earlier generation 1049 00:45:48,849 --> 00:45:45,890 instrument and then with c3 is why Field 1050 00:45:50,469 --> 00:45:48,859 Camera 3 which as you can see gives us a 1051 00:45:51,969 --> 00:45:50,479 wide field of view and we can see 1052 00:45:56,319 --> 00:45:51,979 high-resolution images of many 1053 00:45:58,299 --> 00:45:56,329 protostars at once so here we can see 1054 00:46:00,519 --> 00:45:58,309 some edge on protostars where we're 1055 00:46:02,289 --> 00:46:00,529 looking through a dusty disc and we can 1056 00:46:05,109 --> 00:46:02,299 see some of the outflow cavities 1057 00:46:07,209 --> 00:46:05,119 here we see some point like protostars 1058 00:46:08,890 --> 00:46:07,219 or maybe we're looking more pull on and 1059 00:46:11,469 --> 00:46:08,900 just seeing the light from the central 1060 00:46:13,569 --> 00:46:11,479 regions of the system and we can see all 1061 00:46:15,279 --> 00:46:13,579 sorts of details about exactly how gas 1062 00:46:19,490 --> 00:46:15,289 and dust are distributed around these 1063 00:46:21,050 --> 00:46:19,500 stars and 1064 00:46:22,700 --> 00:46:21,060 is just a demonstration of what you can 1065 00:46:25,190 --> 00:46:22,710 really do with the high resolution of 1066 00:46:26,600 --> 00:46:25,200 Hubble in the 1980s if you looked in 1067 00:46:29,480 --> 00:46:26,610 review papers you would see these 1068 00:46:31,880 --> 00:46:29,490 cartoons showing how stars and disks and 1069 00:46:35,390 --> 00:46:31,890 maybe outflow cavities worked well when 1070 00:46:37,970 --> 00:46:35,400 we did our Hubble imaging we found you 1071 00:46:39,950 --> 00:46:37,980 know Hubble or we found cart it was 1072 00:46:42,770 --> 00:46:39,960 almost like those cartoons have become 1073 00:46:45,530 --> 00:46:42,780 reality here in this image of a star 1074 00:46:47,680 --> 00:46:45,540 called hops 136 we can see everything 1075 00:46:52,990 --> 00:46:47,690 that people predicted in these cartoons 1076 00:46:55,790 --> 00:46:53,000 20-30 years ago we see these dark lanes 1077 00:46:58,670 --> 00:46:55,800 which is the sort of circumstellar disk 1078 00:47:00,710 --> 00:46:58,680 seen in projection we see these bright 1079 00:47:05,090 --> 00:47:00,720 nebulae from the upper layers of the 1080 00:47:07,220 --> 00:47:05,100 disk the disk casts a shadow here we can 1081 00:47:09,110 --> 00:47:07,230 see light being scattered off the inner 1082 00:47:11,390 --> 00:47:09,120 edges of the envelope and then the 1083 00:47:14,090 --> 00:47:11,400 outflow cavities so it's all there 1084 00:47:17,960 --> 00:47:14,100 just as the theorists of the 1980s we're 1085 00:47:19,220 --> 00:47:17,970 predicting one of the things we can do 1086 00:47:22,850 --> 00:47:19,230 with these Hubble images is study 1087 00:47:27,110 --> 00:47:22,860 multiple systems so protostars rarely 1088 00:47:29,330 --> 00:47:27,120 form as single stars they tend to form 1089 00:47:30,800 --> 00:47:29,340 in double systems or triple systems 1090 00:47:33,350 --> 00:47:30,810 sometimes you even have quadruple 1091 00:47:36,200 --> 00:47:33,360 systems something about the way stars 1092 00:47:39,080 --> 00:47:36,210 form tends to form leads them to form in 1093 00:47:40,700 --> 00:47:39,090 pairs or even greater systems and here 1094 00:47:43,490 --> 00:47:40,710 are some examples of these here's a 1095 00:47:45,380 --> 00:47:43,500 binary system where the top one is one 1096 00:47:47,240 --> 00:47:45,390 of these edge-on discs where you can see 1097 00:47:49,190 --> 00:47:47,250 this dark lane and then submit below see 1098 00:47:51,500 --> 00:47:49,200 on either side of it and then the 1099 00:47:53,600 --> 00:47:51,510 southern member of the pair is seen more 1100 00:47:56,030 --> 00:47:53,610 pull on so the light from the central 1101 00:48:00,140 --> 00:47:56,040 regions is escaping it's just a point of 1102 00:48:02,000 --> 00:48:00,150 light here's a triple system a double 1103 00:48:04,190 --> 00:48:02,010 system where this more distant one might 1104 00:48:06,740 --> 00:48:04,200 be related and here's a very close 1105 00:48:08,660 --> 00:48:06,750 double what's interesting about these 1106 00:48:10,760 --> 00:48:08,670 young stars they form in these little 1107 00:48:13,250 --> 00:48:10,770 clusters of two or three or more stars 1108 00:48:15,260 --> 00:48:13,260 but then if you go look at main sequence 1109 00:48:17,480 --> 00:48:15,270 stars more evolved ones you don't see 1110 00:48:19,190 --> 00:48:17,490 nearly as many pairs you still see a lot 1111 00:48:20,840 --> 00:48:19,200 of them but not quite as many so 1112 00:48:22,730 --> 00:48:20,850 something about the way these stars are 1113 00:48:24,590 --> 00:48:22,740 interacting through their gravity the 1114 00:48:26,930 --> 00:48:24,600 third member of a system might get flung 1115 00:48:29,060 --> 00:48:26,940 out so you're left with just a binary 1116 00:48:30,860 --> 00:48:29,070 system where there used to be three it's 1117 00:48:32,660 --> 00:48:30,870 possible that the Sun may even have 1118 00:48:32,900 --> 00:48:32,670 formed in one of these small collections 1119 00:48:37,180 --> 00:48:32,910 of 1120 00:48:40,640 --> 00:48:39,260 another exciting thing we can do with 1121 00:48:43,190 --> 00:48:40,650 these Hubble images is to study the 1122 00:48:44,870 --> 00:48:43,200 cavities and the outflows here you can 1123 00:48:46,430 --> 00:48:44,880 see all sorts of different morphologies 1124 00:48:47,240 --> 00:48:46,440 it's pretty surprising they're not at 1125 00:48:50,660 --> 00:48:47,250 all alike 1126 00:48:52,910 --> 00:48:50,670 you have examples up here of bipolar 1127 00:48:54,890 --> 00:48:52,920 systems where you have this dark lane 1128 00:48:58,550 --> 00:48:54,900 and then the two nebulae on either side 1129 00:49:00,740 --> 00:48:58,560 that are pretty symmetrical here you see 1130 00:49:03,410 --> 00:49:00,750 this huge system that's a little bit of 1131 00:49:07,550 --> 00:49:03,420 a symmetrical here's kind of a smaller 1132 00:49:09,080 --> 00:49:07,560 more tightly contained one this one one 1133 00:49:11,870 --> 00:49:09,090 side of the nebula is much brighter than 1134 00:49:13,520 --> 00:49:11,880 the other down here you have all sorts 1135 00:49:15,560 --> 00:49:13,530 of structure like there have been maybe 1136 00:49:18,440 --> 00:49:15,570 multiple outbursts from this system in 1137 00:49:20,510 --> 00:49:18,450 the past this bizarre ring-like 1138 00:49:23,950 --> 00:49:20,520 structure here's a very wide angle 1139 00:49:26,390 --> 00:49:23,960 outflow there's lots going on here and 1140 00:49:28,610 --> 00:49:26,400 we think that one of the important 1141 00:49:30,410 --> 00:49:28,620 things these cavities do is these cos 1142 00:49:32,300 --> 00:49:30,420 star formation to slow down and 1143 00:49:34,310 --> 00:49:32,310 eventually stop in a star forming region 1144 00:49:36,320 --> 00:49:34,320 the outflow is being launched from the 1145 00:49:38,030 --> 00:49:36,330 star disrupt the cloud and eventually 1146 00:49:40,130 --> 00:49:38,040 there's not enough dense material to 1147 00:49:44,530 --> 00:49:40,140 continue forming stars so we think this 1148 00:49:50,150 --> 00:49:47,300 Alma is another facility this one on the 1149 00:49:53,120 --> 00:49:50,160 ground Alma is the Atacama Large 1150 00:49:54,680 --> 00:49:53,130 millimeter array where millimetre refers 1151 00:49:58,220 --> 00:49:54,690 to the wavelengths of the light that 1152 00:50:00,620 --> 00:49:58,230 we're studying and as an array it's 1153 00:50:03,620 --> 00:50:00,630 actually a collection of sort of medium 1154 00:50:05,600 --> 00:50:03,630 sized radio telescopes they're not quite 1155 00:50:08,180 --> 00:50:05,610 radio telescopes but they're there they 1156 00:50:10,550 --> 00:50:08,190 work like them and by using an array of 1157 00:50:11,990 --> 00:50:10,560 telescopes you can get some of the 1158 00:50:14,060 --> 00:50:12,000 benefits of having a single large 1159 00:50:15,950 --> 00:50:14,070 telescope but you can kind of 1160 00:50:18,260 --> 00:50:15,960 reconfigure the different dishes to 1161 00:50:22,070 --> 00:50:18,270 study physical structures at different 1162 00:50:23,900 --> 00:50:22,080 scales Alma is on the ground but it's 1163 00:50:26,200 --> 00:50:23,910 kind of almost in the sky because it's 1164 00:50:29,720 --> 00:50:26,210 sixteen thousand feet above sea level 1165 00:50:32,810 --> 00:50:29,730 one of the highest flat places on the 1166 00:50:35,030 --> 00:50:32,820 Earth's surface up there the air is 1167 00:50:39,260 --> 00:50:35,040 exceedingly dry it really doesn't rain 1168 00:50:44,150 --> 00:50:39,270 there ever and exceedingly thin so it's 1169 00:50:46,370 --> 00:50:44,160 almost as though you're in space these 1170 00:50:49,670 --> 00:50:46,380 are images of 1171 00:50:51,380 --> 00:50:49,680 pterri disks in orion so we're looking 1172 00:50:55,010 --> 00:50:51,390 through the envelope and imaging the 1173 00:50:57,410 --> 00:50:55,020 disks themselves and the important thing 1174 00:50:59,210 --> 00:50:57,420 here is for comparison if something just 1175 00:51:01,190 --> 00:50:59,220 like neptune were orbiting one of these 1176 00:51:05,780 --> 00:51:01,200 stars at the same distance from its star 1177 00:51:07,790 --> 00:51:05,790 as neptune is you would be able to you 1178 00:51:09,020 --> 00:51:07,800 know resolve the orbit of neptune so 1179 00:51:11,450 --> 00:51:09,030 we're really getting to the point where 1180 00:51:13,610 --> 00:51:11,460 we can witness not just stars but the 1181 00:51:15,800 --> 00:51:13,620 Syst solar systems the systems of proto 1182 00:51:17,600 --> 00:51:15,810 planets themselves in the act of 1183 00:51:19,610 --> 00:51:17,610 formation this is really cutting-edge 1184 00:51:21,350 --> 00:51:19,620 science and Alma's continuing to get 1185 00:51:23,510 --> 00:51:21,360 more powerful and more able to resolve 1186 00:51:25,070 --> 00:51:23,520 these fine structures so there are lots 1187 00:51:27,470 --> 00:51:25,080 of debates going on right now about 1188 00:51:29,240 --> 00:51:27,480 which stars have planets and which ones 1189 00:51:33,380 --> 00:51:29,250 or maybe just beginning to form planets 1190 00:51:34,970 --> 00:51:33,390 I want to talk a little bit about the 1191 00:51:39,050 --> 00:51:34,980 science that I'm doing in particular 1192 00:51:40,790 --> 00:51:39,060 with star formation in Orion so I'm 1193 00:51:41,840 --> 00:51:40,800 interested in out bursting protostars 1194 00:51:45,350 --> 00:51:41,850 and I'll show you what I mean by that 1195 00:51:47,480 --> 00:51:45,360 this is a wide field image of Orion 1196 00:51:49,040 --> 00:51:47,490 starting the Orion Nebula is off the top 1197 00:51:50,930 --> 00:51:49,050 of the page and then this is this kind 1198 00:51:53,120 --> 00:51:50,940 of suburban region of Orion that I was 1199 00:51:54,440 --> 00:51:53,130 telling you about the circle toward the 1200 00:51:57,650 --> 00:51:54,450 bottom of the image marks the location 1201 00:51:59,120 --> 00:51:57,660 of hops 2:23 it's fairly isolated it's 1202 00:52:01,910 --> 00:51:59,130 part of this little group of three young 1203 00:52:06,130 --> 00:52:01,920 stars this is a near infrared image of 1204 00:52:09,410 --> 00:52:06,140 hops 2:23 and friends in the late 90s 1205 00:52:11,360 --> 00:52:09,420 ops 223 pretty faint compared to the 1206 00:52:14,930 --> 00:52:11,370 other two objects in the field well we 1207 00:52:17,630 --> 00:52:14,940 came and looked again in 2011 it was 1208 00:52:20,330 --> 00:52:17,640 suddenly much brighter now the brightest 1209 00:52:22,670 --> 00:52:20,340 object in the field so something 1210 00:52:24,980 --> 00:52:22,680 happened here that may tell us about how 1211 00:52:28,280 --> 00:52:24,990 stars form this is a Hubble image of 1212 00:52:31,070 --> 00:52:28,290 hops 223 and friends this is hops 223 1213 00:52:33,140 --> 00:52:31,080 this is hops 221 down here the numbers 1214 00:52:35,090 --> 00:52:33,150 are not quite randomly assigned they 1215 00:52:36,440 --> 00:52:35,100 don't they don't mean a whole lot but 1216 00:52:38,630 --> 00:52:36,450 this is just a little collection of 1217 00:52:42,950 --> 00:52:38,640 stars and hops 223 is undergoing one of 1218 00:52:45,410 --> 00:52:42,960 these outbursts we think that the reason 1219 00:52:47,720 --> 00:52:45,420 these get so much brighter is because 1220 00:52:49,970 --> 00:52:47,730 they suddenly begin this episode of 1221 00:52:51,830 --> 00:52:49,980 rapid mass accretion there may be 1222 00:52:53,690 --> 00:52:51,840 gradually accreting material from there 1223 00:52:54,920 --> 00:52:53,700 circumstellar disks over a period of 1224 00:52:57,260 --> 00:52:54,930 thousands of years and then suddenly 1225 00:52:59,120 --> 00:52:57,270 something happens to cause material to 1226 00:53:01,790 --> 00:52:59,130 pour on it pour unto the star 1227 00:53:02,900 --> 00:53:01,800 more rapidly these are light curves if 1228 00:53:04,340 --> 00:53:02,910 you remember way back near the beginning 1229 00:53:06,680 --> 00:53:04,350 of the talk I showed you a light curve 1230 00:53:09,410 --> 00:53:06,690 of a typical young star these are light 1231 00:53:12,530 --> 00:53:09,420 curves of three famous outbursts this 1232 00:53:16,010 --> 00:53:12,540 one here was a pretty normal star in 1233 00:53:18,170 --> 00:53:16,020 about 1935 but then suddenly just in a 1234 00:53:20,960 --> 00:53:18,180 span of months it became more than 100 1235 00:53:24,050 --> 00:53:20,970 times brighter shot way up here and ever 1236 00:53:26,210 --> 00:53:24,060 since then for decades it's been slowly 1237 00:53:27,620 --> 00:53:26,220 trailing off in brightness but it's 1238 00:53:29,960 --> 00:53:27,630 still much brighter than it ever was 1239 00:53:32,930 --> 00:53:29,970 before hand and there are a couple of 1240 00:53:34,640 --> 00:53:32,940 other objects that were detected back in 1241 00:53:36,140 --> 00:53:34,650 the twentieth century to do this and 1242 00:53:39,980 --> 00:53:36,150 we've started finding more and more of 1243 00:53:41,930 --> 00:53:39,990 them more recently so these outbursts 1244 00:53:44,210 --> 00:53:41,940 may actually be essential for the 1245 00:53:45,920 --> 00:53:44,220 formation of a star we think it's 1246 00:53:48,020 --> 00:53:45,930 possible that most of a star's mass 1247 00:53:49,760 --> 00:53:48,030 might be assembled in a series of a few 1248 00:53:51,350 --> 00:53:49,770 dozens of these outbursts over the two 1249 00:53:53,300 --> 00:53:51,360 million years star formation period 1250 00:53:57,590 --> 00:53:53,310 rather than as a slow and gradual 1251 00:53:59,060 --> 00:53:57,600 process a lot of theorists have put 1252 00:54:01,130 --> 00:53:59,070 together simulations of how these 1253 00:54:03,440 --> 00:54:01,140 outbursts work so a little bit about the 1254 00:54:06,410 --> 00:54:03,450 physics of star formation this is a 1255 00:54:09,200 --> 00:54:06,420 scenario so in this image the star is 1256 00:54:12,890 --> 00:54:09,210 here at the center in yellow of the 1257 00:54:15,980 --> 00:54:12,900 system this is all disc material so the 1258 00:54:18,620 --> 00:54:15,990 Stars disk is gradually drifting inward 1259 00:54:20,060 --> 00:54:18,630 trying to accrete onto the star but the 1260 00:54:21,830 --> 00:54:20,070 star has got a magnetic field it's just 1261 00:54:23,060 --> 00:54:21,840 like a bar magnet it's got a North Pole 1262 00:54:25,760 --> 00:54:23,070 and a South Pole in a magnetic field 1263 00:54:27,560 --> 00:54:25,770 that magnetic field keeps the disk from 1264 00:54:30,050 --> 00:54:27,570 coming in all the way so then the 1265 00:54:31,940 --> 00:54:30,060 material instead flows along these field 1266 00:54:32,720 --> 00:54:31,950 lines and crashes into the star at high 1267 00:54:35,510 --> 00:54:32,730 latitudes 1268 00:54:37,130 --> 00:54:35,520 we call this magnetospheric accretion 1269 00:54:40,130 --> 00:54:37,140 it's the accretion of gas through the 1270 00:54:42,740 --> 00:54:40,140 star's magnetosphere but when an 1271 00:54:44,840 --> 00:54:42,750 outburst begins there's maybe some blob 1272 00:54:46,160 --> 00:54:44,850 in the disk that's debt much denser than 1273 00:54:48,320 --> 00:54:46,170 the rest of the disk and when that 1274 00:54:50,900 --> 00:54:48,330 accretes it brings a lot more pressure 1275 00:54:52,400 --> 00:54:50,910 with it so the disc plows into the 1276 00:54:54,200 --> 00:54:52,410 surface of the star right at its equator 1277 00:54:56,810 --> 00:54:54,210 it completely overwhelms the star's 1278 00:54:59,630 --> 00:54:56,820 magnetic field and some of that material 1279 00:55:02,030 --> 00:54:59,640 gets shot off along the poles to form 1280 00:55:04,040 --> 00:55:02,040 these outflows so it's an entirely 1281 00:55:06,200 --> 00:55:04,050 different scenario for these stars 1282 00:55:08,600 --> 00:55:06,210 getting built up and this seems to 1283 00:55:11,960 --> 00:55:08,610 persist for maybe hundreds of years all 1284 00:55:12,870 --> 00:55:11,970 of these out bursting stars we've never 1285 00:55:14,610 --> 00:55:12,880 seen one 1286 00:55:20,360 --> 00:55:14,620 the major outburst turn off completely 1287 00:55:25,560 --> 00:55:23,070 used one more space telescope called 1288 00:55:26,970 --> 00:55:25,570 wise this is the wide-field Infrared 1289 00:55:28,920 --> 00:55:26,980 Survey Explorer and it's one of the 1290 00:55:30,840 --> 00:55:28,930 smallest ones probably the smallest one 1291 00:55:32,760 --> 00:55:30,850 we've discussed so far it's kind of a 1292 00:55:35,400 --> 00:55:32,770 small but mighty Space Telescope though 1293 00:55:37,440 --> 00:55:35,410 it was launched in 2009 and it did a 1294 00:55:39,720 --> 00:55:37,450 survey of the entire sky it was very 1295 00:55:42,660 --> 00:55:39,730 flexible it did an all-sky survey in 1296 00:55:44,640 --> 00:55:42,670 2010 and it's continuing to orbit the 1297 00:55:46,650 --> 00:55:44,650 Earth performing a search for near-earth 1298 00:55:49,590 --> 00:55:46,660 asteroids which is pretty important if 1299 00:55:51,570 --> 00:55:49,600 you think about it this is an image of 1300 00:55:54,180 --> 00:55:51,580 the Milky Way from the wise telescope 1301 00:55:57,480 --> 00:55:54,190 and we actually used it to search for 1302 00:56:00,630 --> 00:55:57,490 more outbursts Spitzer made a map of a 1303 00:56:02,700 --> 00:56:00,640 Ryan in 2004 wise came around in 2010 1304 00:56:05,040 --> 00:56:02,710 and did the same thing and we could do a 1305 00:56:06,960 --> 00:56:05,050 computer-based comparison of the two 1306 00:56:11,160 --> 00:56:06,970 maps to look for stars that got much 1307 00:56:13,370 --> 00:56:11,170 brighter in the intervening time we have 1308 00:56:16,740 --> 00:56:13,380 one really great find of an outburst 1309 00:56:18,570 --> 00:56:16,750 when I was a postdoc at Toledo Emily 1310 00:56:20,940 --> 00:56:18,580 shown here was working with me on her 1311 00:56:24,900 --> 00:56:20,950 senior thesis and discovered Hopps 383 1312 00:56:28,020 --> 00:56:24,910 an out bursting proto star in Orion this 1313 00:56:30,240 --> 00:56:28,030 is a fairly large image of part of Orion 1314 00:56:32,070 --> 00:56:30,250 with the nebula here hops 383 is just to 1315 00:56:33,600 --> 00:56:32,080 the north of it along one of these dark 1316 00:56:37,200 --> 00:56:33,610 filaments that I've been talking about 1317 00:56:40,260 --> 00:56:37,210 from time to time these are the Spitzer 1318 00:56:41,670 --> 00:56:40,270 images of hops 383 where you can barely 1319 00:56:44,670 --> 00:56:41,680 see it at the shortest spitzer 1320 00:56:46,230 --> 00:56:44,680 wavelengths pokes out a little bit here 1321 00:56:48,510 --> 00:56:46,240 and then at the longest spitzer 1322 00:56:49,740 --> 00:56:48,520 wavelengths it's it's faint nothing you 1323 00:56:50,870 --> 00:56:49,750 would have imagined was a protostar 1324 00:56:53,550 --> 00:56:50,880 maybe some kind of background 1325 00:56:56,310 --> 00:56:53,560 contamination or something but here it 1326 00:56:58,620 --> 00:56:56,320 is in wise look how bright it is the 1327 00:57:00,180 --> 00:56:58,630 longest why of wise wavelengths this was 1328 00:57:01,860 --> 00:57:00,190 an unambiguous sign that something 1329 00:57:04,530 --> 00:57:01,870 happened in this object something made 1330 00:57:09,390 --> 00:57:04,540 it get a factor of a few dozen brighter 1331 00:57:11,490 --> 00:57:09,400 between 2004 and 2010 this is actually 1332 00:57:14,790 --> 00:57:11,500 the youngest known out bursting 1333 00:57:17,010 --> 00:57:14,800 protostar it's barely visible at the 1334 00:57:19,290 --> 00:57:17,020 shortest wise wavelengths even now and 1335 00:57:21,150 --> 00:57:19,300 it's extremely bright as you go farther 1336 00:57:22,700 --> 00:57:21,160 and farther out into the infrared that 1337 00:57:26,340 --> 00:57:22,710 means it's young and deeply embedded 1338 00:57:27,240 --> 00:57:26,350 it's maybe a hundred thousand years old 1339 00:57:28,890 --> 00:57:27,250 give 1340 00:57:31,770 --> 00:57:28,900 it's hard to date these things precisely 1341 00:57:33,330 --> 00:57:31,780 but it's it's young so even in their 1342 00:57:35,100 --> 00:57:33,340 earliest stages these stars undergo 1343 00:57:37,470 --> 00:57:35,110 these outbursts which is evidence that 1344 00:57:39,780 --> 00:57:37,480 this is a really important aspect of 1345 00:57:42,840 --> 00:57:39,790 star formation this was enough to 1346 00:57:44,550 --> 00:57:42,850 generate a press release here's an image 1347 00:57:46,830 --> 00:57:44,560 from our press really showing that 1348 00:57:48,240 --> 00:57:46,840 before pictures here in the after 1349 00:57:51,180 --> 00:57:48,250 pictures in the bottom row 1350 00:57:54,540 --> 00:57:51,190 these are near infrared images from Kitt 1351 00:57:57,150 --> 00:57:54,550 Peak and what we found so we have over 1352 00:57:59,790 --> 00:57:57,160 300 protostars here two of them began 1353 00:58:02,760 --> 00:57:59,800 outbursts in a period of a few years 1354 00:58:04,470 --> 00:58:02,770 between 2004 and 2010 there's hops 2:23 1355 00:58:08,790 --> 00:58:04,480 that i started off talking about and 1356 00:58:10,860 --> 00:58:08,800 hops 383 shown here that's kind of small 1357 00:58:13,230 --> 00:58:10,870 number of Statistics but it's an 1358 00:58:14,670 --> 00:58:13,240 indication that any given protostar may 1359 00:58:16,560 --> 00:58:14,680 have an outburst like this once every 1360 00:58:18,660 --> 00:58:16,570 thousand years that's where that number 1361 00:58:21,480 --> 00:58:18,670 comes from the protostar might do this 1362 00:58:25,370 --> 00:58:21,490 50 times over its formation period so 1363 00:58:27,210 --> 00:58:25,380 these protostars are active young stars 1364 00:58:31,640 --> 00:58:27,220 engaging in some pretty dramatic 1365 00:58:36,330 --> 00:58:34,640 the lasts are just about the last 1366 00:58:38,430 --> 00:58:36,340 observatory I'm going to tell you about 1367 00:58:40,230 --> 00:58:38,440 is Sophia this is not technically a 1368 00:58:42,150 --> 00:58:40,240 space-based observatories it comes 1369 00:58:44,670 --> 00:58:42,160 pretty close this is the stratospheric 1370 00:58:46,350 --> 00:58:44,680 Observatory for infrared astronomy it's 1371 00:58:49,560 --> 00:58:46,360 actually a passenger plane that has been 1372 00:58:51,720 --> 00:58:49,570 turned into a telescope if you see this 1373 00:58:54,120 --> 00:58:51,730 large rectangular opening in the back of 1374 00:58:56,160 --> 00:58:54,130 the plane this plane takes off every 1375 00:58:59,340 --> 00:58:56,170 night from Palmdale California in the 1376 00:59:01,050 --> 00:58:59,350 desert near Los Angeles sometimes it can 1377 00:59:03,300 --> 00:59:01,060 observe the southern sky by taking off 1378 00:59:05,730 --> 00:59:03,310 from New Zealand and after it reaches 1379 00:59:07,320 --> 00:59:05,740 cruising altitude this door opens up in 1380 00:59:09,480 --> 00:59:07,330 the back of the plane to let the 1381 00:59:12,990 --> 00:59:09,490 telescope peer out into the mid infrared 1382 00:59:15,210 --> 00:59:13,000 sky the cool thing about Sofia is that 1383 00:59:18,240 --> 00:59:15,220 astronomers who get time to use Sofia 1384 00:59:20,850 --> 00:59:18,250 are able to fly on it so you can kind of 1385 00:59:23,490 --> 00:59:20,860 see the whole flight operations crew in 1386 00:59:26,280 --> 00:59:23,500 action this is a view from inside of the 1387 00:59:30,630 --> 00:59:26,290 observatory where instead of tightly 1388 00:59:35,010 --> 00:59:30,640 packed rows of Economy seats you see all 1389 00:59:36,520 --> 00:59:35,020 of these scientific workstations all so 1390 00:59:38,470 --> 00:59:36,530 tightly packed 1391 00:59:40,810 --> 00:59:38,480 there's a flight commander that sort of 1392 00:59:42,280 --> 00:59:40,820 makes sure the pilots and the scientists 1393 00:59:43,330 --> 00:59:42,290 understand what each other is trying to 1394 00:59:45,730 --> 00:59:43,340 do and make sure everything goes 1395 00:59:47,980 --> 00:59:45,740 smoothly you have instrument scientists 1396 00:59:50,200 --> 00:59:47,990 on board and then the astronomers who 1397 00:59:52,540 --> 00:59:50,210 got time are just kind of there trying 1398 00:59:54,340 --> 00:59:52,550 not to cause too many problems and 1399 00:59:55,570 --> 00:59:54,350 trying not to interfere with the process 1400 00:59:57,940 --> 00:59:55,580 too much we're just learning how it all 1401 00:59:59,770 --> 00:59:57,950 works in the back of this image we're 1402 01:00:01,480 --> 00:59:59,780 actually seeing the right side of the 1403 01:00:04,780 --> 01:00:01,490 telescope the telescopes peering out of 1404 01:00:06,280 --> 01:00:04,790 the plane this way and this is you know 1405 01:00:07,990 --> 01:00:06,290 just the side of the telescope and the 1406 01:00:11,890 --> 01:00:08,000 instruments get attached they're that 1407 01:00:13,480 --> 01:00:11,900 detect and record the light and Sofia 1408 01:00:15,330 --> 01:00:13,490 flies pretty high many of its 1409 01:00:18,130 --> 01:00:15,340 observations are conducted from 35 1410 01:00:20,440 --> 01:00:18,140 37,000 feet but to go out to the longest 1411 01:00:22,810 --> 01:00:20,450 wavelengths it goes up above 40,000 feet 1412 01:00:25,270 --> 01:00:22,820 where the air is you know as thin as you 1413 01:00:27,610 --> 01:00:25,280 can get access to and as dry as you can 1414 01:00:29,860 --> 01:00:27,620 get access to so it leads to some fairly 1415 01:00:32,290 --> 01:00:29,870 sensitive infrared studies it's not 1416 01:00:36,670 --> 01:00:32,300 quite as sensitive as a Spitzer or 1417 01:00:38,290 --> 01:00:36,680 Herschel but it lands every morning so 1418 01:00:54,670 --> 01:00:38,300 you can go and fix things and improve 1419 01:00:58,840 --> 01:00:54,680 things yeah question the telescope is 1420 01:01:00,700 --> 01:00:58,850 yeah is isolated in that sense and it's 1421 01:01:02,140 --> 01:01:00,710 kind of interesting to watch it when 1422 01:01:04,030 --> 01:01:02,150 you're flying because it looks like the 1423 01:01:05,800 --> 01:01:04,040 telescope is rotating but it's actually 1424 01:01:08,970 --> 01:01:05,810 the plane sort of moving around and the 1425 01:01:19,930 --> 01:01:08,980 telescope is engineered to remain steady 1426 01:01:22,360 --> 01:01:19,940 yeah right it's I don't understand the 1427 01:01:24,760 --> 01:01:22,370 details precisely but it's it's sort of 1428 01:01:27,610 --> 01:01:24,770 it's it's isolated in such a way that it 1429 01:01:33,010 --> 01:01:27,620 can move freely or rather you know stay 1430 01:01:38,650 --> 01:01:36,370 so this is our image and image of hops 1431 01:01:40,540 --> 01:01:38,660 383 with Sophia it's this faint fuzzy 1432 01:01:43,450 --> 01:01:40,550 blob in the center of this circle here 1433 01:01:45,160 --> 01:01:43,460 so with Sophia we're just barely able to 1434 01:01:48,130 --> 01:01:45,170 detect something deeply as embedded as 1435 01:01:49,810 --> 01:01:48,140 hops 383 but we can detect it well 1436 01:01:53,109 --> 01:01:49,820 enough to know that it's still in out 1437 01:01:55,690 --> 01:01:53,119 burst mode in 2016 10 years after the 1438 01:01:58,300 --> 01:01:55,700 outburst began and this is currently the 1439 01:02:01,780 --> 01:01:58,310 best way we have of monitoring outbursts 1440 01:02:03,760 --> 01:02:01,790 in the infrared coming along a few years 1441 01:02:05,890 --> 01:02:03,770 down the road Road though is James Webb 1442 01:02:08,140 --> 01:02:05,900 and from the perspective of somebody who 1443 01:02:09,520 --> 01:02:08,150 studies star formation Webb has two 1444 01:02:12,580 --> 01:02:09,530 advantages it's going to have the 1445 01:02:15,340 --> 01:02:12,590 detailed high-resolution view of Hubble 1446 01:02:18,310 --> 01:02:15,350 but also the infrared capabilities of 1447 01:02:20,140 --> 01:02:18,320 Spitzer so by combining those two we can 1448 01:02:22,960 --> 01:02:20,150 really begin to look at the most deeply 1449 01:02:25,120 --> 01:02:22,970 embedded protostars study how often they 1450 01:02:26,740 --> 01:02:25,130 have outbursts and start to learn 1451 01:02:28,780 --> 01:02:26,750 something about the precise physical 1452 01:02:31,510 --> 01:02:28,790 conditions that exist in the innermost 1453 01:02:33,190 --> 01:02:31,520 regions of those young stars this is 1454 01:02:35,410 --> 01:02:33,200 just some text from one of the JWST 1455 01:02:37,090 --> 01:02:35,420 science themes to show that star 1456 01:02:41,730 --> 01:02:37,100 formation is supposed to be one of the 1457 01:02:46,510 --> 01:02:44,470 so just to wrap things up here this is a 1458 01:02:49,630 --> 01:02:46,520 whole gallery of all the different 1459 01:02:51,580 --> 01:02:49,640 telescopes from the ground with Alma to 1460 01:02:53,740 --> 01:02:51,590 the stratosphere with Sofia to space 1461 01:02:55,750 --> 01:02:53,750 with all of these guys and they're 1462 01:02:58,990 --> 01:02:55,760 really beginning to reveal the secrets 1463 01:03:01,510 --> 01:02:59,000 of star formation in Orion and this is 1464 01:03:03,520 --> 01:03:01,520 how we learn how our Sun formed all of 1465 01:03:06,460 --> 01:03:03,530 these young stars in the Orion molecular 1466 01:03:08,200 --> 01:03:06,470 clouds their average mass is a little 1467 01:03:11,080 --> 01:03:08,210 bit less than that of the Sun but we 1468 01:03:14,050 --> 01:03:11,090 expect many of them to form planets and 1469 01:03:15,790 --> 01:03:14,060 go through the cycle of sorts just like 1470 01:03:17,560 --> 01:03:15,800 our Sun does so this is really our best 1471 01:03:20,050 --> 01:03:17,570 way to figure out how the Sun and 1472 01:03:22,480 --> 01:03:20,060 planets all formed five billion years 1473 01:03:33,130 --> 01:03:22,490 ago thank you 1474 01:03:46,130 --> 01:03:44,570 yeah question well so you're referring 1475 01:03:48,890 --> 01:03:46,140 to when nuclear fusion begins in the 1476 01:03:50,510 --> 01:03:48,900 corn it becomes a true star it's a 1477 01:03:52,160 --> 01:03:50,520 little bit difficult to see that in the 1478 01:03:55,130 --> 01:03:52,170 act of happening just because it's such 1479 01:03:59,060 --> 01:03:55,140 a slow long process for what's happening 1480 01:04:00,890 --> 01:03:59,070 in the core to propagate outward we see 1481 01:04:06,650 --> 01:04:00,900 lots of stars that are kind of on both 1482 01:04:11,710 --> 01:04:06,660 sides of that boundary those let's go 1483 01:04:20,470 --> 01:04:11,720 into the back Oh research do you have 1484 01:04:27,140 --> 01:04:24,560 so the question was we have an idea of 1485 01:04:30,500 --> 01:04:27,150 how many stars create planets from this 1486 01:04:32,690 --> 01:04:30,510 work from this work and from other work 1487 01:04:34,880 --> 01:04:32,700 it looks like nearly all of them do I 1488 01:04:37,310 --> 01:04:34,890 mean everywhere we look stars have 1489 01:04:39,500 --> 01:04:37,320 planets there's all sorts of evidence 1490 01:04:42,140 --> 01:04:39,510 coming from these Alma images of young 1491 01:04:43,970 --> 01:04:42,150 stars that there is no such thing as a 1492 01:04:45,320 --> 01:04:43,980 perfect disc they're all distorted in 1493 01:04:47,180 --> 01:04:45,330 some way that might be due to planets 1494 01:04:48,500 --> 01:04:47,190 it's kind of an open question still but 1495 01:04:49,910 --> 01:04:48,510 it looks like planets are a pretty 1496 01:04:53,450 --> 01:04:49,920 standard outcome with the star formation 1497 01:04:55,910 --> 01:04:53,460 process I mean when you showed the the 1498 01:04:57,860 --> 01:04:55,920 the disks from Alma I mean almost 1499 01:05:00,080 --> 01:04:57,870 finding a tremendous number of these 1500 01:05:02,210 --> 01:05:00,090 disks around photo stars right right 1501 01:05:03,710 --> 01:05:02,220 it's got its it's it to me is the one 1502 01:05:06,980 --> 01:05:03,720 that has the greatest resolution for 1503 01:05:08,960 --> 01:05:06,990 seeing all these disks mm-hmm yeah are 1504 01:05:10,700 --> 01:05:08,970 our disks in Orion this is kind of a 1505 01:05:12,860 --> 01:05:10,710 snapshot survey but people who go look 1506 01:05:14,450 --> 01:05:12,870 and find detail at any given disk see a 1507 01:05:30,590 --> 01:05:14,460 lot more structure that I show you here 1508 01:05:33,620 --> 01:05:30,600 even yes the accretion process so what 1509 01:05:38,810 --> 01:05:33,630 is the minimum for fusion for minimum 1510 01:05:40,880 --> 01:05:38,820 density or the threshold are you talking 1511 01:05:42,690 --> 01:05:40,890 density are you talking amount of 1512 01:05:45,480 --> 01:05:42,700 material 1513 01:05:48,000 --> 01:05:45,490 all right so was it take first for a 1514 01:05:49,830 --> 01:05:48,010 clump of gas to collapse down and become 1515 01:05:51,180 --> 01:05:49,840 a star what's it what's were the 1516 01:05:52,980 --> 01:05:51,190 thresholds it has to cross 1517 01:05:56,280 --> 01:05:52,990 we often talk in terms of a mass 1518 01:06:01,920 --> 01:05:56,290 accretion rate and the unit's we use are 1519 01:06:04,560 --> 01:06:01,930 solar masses per year so a typical 1520 01:06:06,270 --> 01:06:04,570 t-tauri stars might accrete at 10 to the 1521 01:06:08,250 --> 01:06:06,280 minus 8 solar masses per year that 1522 01:06:09,810 --> 01:06:08,260 really means about one moon's worth of 1523 01:06:12,900 --> 01:06:09,820 material is falling under the star every 1524 01:06:15,180 --> 01:06:12,910 year that's not very much very early in 1525 01:06:17,420 --> 01:06:15,190 the star formation phase the accretion 1526 01:06:28,590 --> 01:06:17,430 rates are maybe ten thousand times that 1527 01:06:30,060 --> 01:06:28,600 so ten to the minus four all right so 1528 01:06:32,370 --> 01:06:30,070 the question the minimum amount of 1529 01:06:37,950 --> 01:06:32,380 matter necessary for fusion for the 1530 01:06:40,320 --> 01:06:37,960 fusion so the least massive stars that 1531 01:06:42,270 --> 01:06:40,330 are fusing hydrogen in their centers are 1532 01:06:51,290 --> 01:06:42,280 a little less than a tenth of a solar 1533 01:07:00,630 --> 01:06:54,870 points or they have to get pretty 1534 01:07:02,220 --> 01:07:00,640 crowded several so Herschel's already 1535 01:07:04,290 --> 01:07:02,230 out of the l2 we're gonna send a web out 1536 01:07:05,090 --> 01:07:04,300 to l2 man is it gonna get crowded out 1537 01:07:08,250 --> 01:07:05,100 there 1538 01:07:10,020 --> 01:07:08,260 yeah the Planck Space Telescope is 1539 01:07:12,210 --> 01:07:10,030 another one that's out there they're not 1540 01:07:15,300 --> 01:07:12,220 all like precisely at one point they're 1541 01:07:18,510 --> 01:07:15,310 all in various orbits around l2 so maybe 1542 01:07:20,400 --> 01:07:18,520 crowded in a sense but not that crowded 1543 01:07:21,570 --> 01:07:20,410 yeah I don't think that's I don't think 1544 01:07:23,220 --> 01:07:21,580 it's a concern that any of them would 1545 01:07:25,770 --> 01:07:23,230 collide geosynchronous orbit around 1546 01:07:38,790 --> 01:07:25,780 Earth is much much much much much more 1547 01:07:42,540 --> 01:07:38,800 crowded okay do stars have an axis and 1548 01:07:45,270 --> 01:07:42,550 magnetic holes and if so why oh well 1549 01:07:47,640 --> 01:07:45,280 yeah they are magnetic it's because the 1550 01:07:50,570 --> 01:07:47,650 gas in these stars is so hot that the 1551 01:07:53,460 --> 01:07:50,580 atoms dissociate into charged particles 1552 01:07:56,200 --> 01:07:53,470 so you have ions protons and electrons 1553 01:07:58,240 --> 01:07:56,210 and the elect 1554 01:08:02,260 --> 01:07:58,250 charge also generates a magnetic field 1555 01:08:04,480 --> 01:08:02,270 and in the least the less massive stars 1556 01:08:05,680 --> 01:08:04,490 you have these convection currents so 1557 01:08:07,150 --> 01:08:05,690 you get a current going with these 1558 01:08:13,390 --> 01:08:07,160 charged particles and that gives you a 1559 01:08:15,310 --> 01:08:13,400 magnetic field yes kind of the opposite 1560 01:08:16,599 --> 01:08:15,320 of the first question I know the things 1561 01:08:20,229 --> 01:08:16,609 start to heat up when they collapse 1562 01:08:26,170 --> 01:08:20,239 gravitationally at what point we start 1563 01:08:28,269 --> 01:08:26,180 are we able to start alright so you has 1564 01:08:30,160 --> 01:08:28,279 to collapse and get darkened when does 1565 01:08:31,720 --> 01:08:30,170 it win where do we able to actually see 1566 01:08:37,229 --> 01:08:31,730 the stars that were your question yeah 1567 01:08:40,570 --> 01:08:37,239 when did when it's with the Herschel 1568 01:08:44,680 --> 01:08:40,580 telescope we were detecting stars that 1569 01:08:47,229 --> 01:08:44,690 had temperatures of maybe 40 to 50 1570 01:08:51,130 --> 01:08:47,239 degrees above absolute zero 40 to 50 1571 01:08:53,590 --> 01:08:51,140 Kelvin so we're getting cold not quite 1572 01:09:09,940 --> 01:08:53,600 as cold as like interstellar space but 1573 01:09:12,640 --> 01:09:09,950 cool so to see them in visible light 1574 01:09:14,229 --> 01:09:12,650 wavelengths what has to happen do we 1575 01:09:16,900 --> 01:09:14,239 and the fusion has to be turned on of 1576 01:09:19,390 --> 01:09:16,910 course so these T Tauri stars that I was 1577 01:09:21,610 --> 01:09:19,400 talking about or what we call optically 1578 01:09:24,820 --> 01:09:21,620 revealed they show up in visible light 1579 01:09:28,690 --> 01:09:24,830 images they're not yet fusing but the 1580 01:09:30,550 --> 01:09:28,700 energy of contraction as the star gets 1581 01:09:32,440 --> 01:09:30,560 smaller from its initial state to 1582 01:09:36,099 --> 01:09:32,450 eventually become dense enough to fuse 1583 01:09:39,280 --> 01:09:36,109 that in itself releases plenty of energy 1584 01:09:42,130 --> 01:09:39,290 and once all that cloud is gone it gets 1585 01:09:44,170 --> 01:09:42,140 radiated as visible light so even even 1586 01:09:47,140 --> 01:09:44,180 before hydrogen fuses you can see 1587 01:09:48,910 --> 01:09:47,150 optical light from these and a lot of 1588 01:09:51,010 --> 01:09:48,920 that's geometric of course too because 1589 01:09:52,990 --> 01:09:51,020 if they're deeply embedded within the 1590 01:09:54,880 --> 01:09:53,000 molecular cloud you're not going to see 1591 01:09:57,550 --> 01:09:54,890 them whereas Orion is like a blister 1592 01:09:59,530 --> 01:09:57,560 nebula so if we're able to see there's a 1593 01:10:19,770 --> 01:09:59,540 relatively clear right there site and 1594 01:10:30,700 --> 01:10:22,360 so what's the day how big are these 1595 01:10:32,470 --> 01:10:30,710 Lagrangian points the area yeah I'm not 1596 01:10:39,040 --> 01:10:32,480 sure what exactly the radius of the 1597 01:10:40,450 --> 01:10:39,050 orbit around the l2 point is it's it's 1598 01:10:42,040 --> 01:10:40,460 large enough that their telescopes are 1599 01:10:46,570 --> 01:10:42,050 not colliding within one another but I'm 1600 01:10:47,770 --> 01:10:46,580 not sure I'm not sure numerically the 1601 01:10:50,380 --> 01:10:47,780 Webb Space Telescope's 1602 01:10:52,870 --> 01:10:50,390 library market is really quite large I 1603 01:10:56,410 --> 01:10:52,880 mean it's several Earth radii in in 1604 01:11:00,940 --> 01:10:56,420 diameter at least I don't know I also 1605 01:11:03,910 --> 01:11:00,950 don't know an actual number yeah well 1606 01:11:05,770 --> 01:11:03,920 it's just it's a nice big library more 1607 01:11:11,410 --> 01:11:05,780 of it around the around the veil to 1608 01:11:15,700 --> 01:11:11,420 point any idea the length of life of a 1609 01:11:19,230 --> 01:11:15,710 star-forming region so what is the how 1610 01:11:21,970 --> 01:11:19,240 long does a star-forming region last 1611 01:11:24,490 --> 01:11:21,980 that's a little hard to tell we we have 1612 01:11:26,410 --> 01:11:24,500 some sense for how long the individual 1613 01:11:28,180 --> 01:11:26,420 stars last but you might get successive 1614 01:11:30,910 --> 01:11:28,190 waves of star formation before the gas 1615 01:11:33,250 --> 01:11:30,920 is fully exhausted so you maybe will 1616 01:11:34,390 --> 01:11:33,260 have a you know if the average time it 1617 01:11:36,100 --> 01:11:34,400 takes to form a star as two million 1618 01:11:40,170 --> 01:11:36,110 years maybe the star forming region 1619 01:11:43,390 --> 01:11:40,180 itself could last for a few times that 1620 01:11:45,160 --> 01:11:43,400 small interestingly compared to like 1621 01:11:46,660 --> 01:11:45,170 geologic timescales like when the 1622 01:11:48,540 --> 01:11:46,670 dinosaurs roamed the earth there is 1623 01:11:50,770 --> 01:11:48,550 probably no Orion Nebula yet to speak of 1624 01:11:56,530 --> 01:11:50,780 just for a little bit of comparison 1625 01:11:58,810 --> 01:11:56,540 there yes when you look at us the Orion 1626 01:12:03,810 --> 01:11:58,820 Nebula through a small telescope you see 1627 01:12:06,450 --> 01:12:03,820 these four stars trapezium arrangement 1628 01:12:09,070 --> 01:12:06,460 how did they relate to your talk tonight 1629 01:12:10,780 --> 01:12:09,080 alright so how do the trapezium stars at 1630 01:12:13,270 --> 01:12:10,790 the core of Orion relate to what you're 1631 01:12:15,490 --> 01:12:13,280 talking about today those are the most 1632 01:12:16,720 --> 01:12:15,500 massive stars in Orion and those are 1633 01:12:18,610 --> 01:12:16,730 part of what makes it such an 1634 01:12:20,740 --> 01:12:18,620 interesting star forming region that's 1635 01:12:22,600 --> 01:12:20,750 the closest star forming 1636 01:12:27,790 --> 01:12:22,610 and where you have stars that massive 1637 01:12:31,210 --> 01:12:27,800 and the winds the outflows energetic 1638 01:12:33,610 --> 01:12:31,220 outflows from these stars tend to shape 1639 01:12:35,800 --> 01:12:33,620 the entire dynamics and evolution of the 1640 01:12:37,540 --> 01:12:35,810 immediate Orion Nebula region there are 1641 01:12:39,280 --> 01:12:37,550 largely responsible for a lot of the 1642 01:12:42,310 --> 01:12:39,290 bright emission you see from the nebula 1643 01:12:45,760 --> 01:12:42,320 they may play a role in sort of blasting 1644 01:12:47,500 --> 01:12:45,770 discs away from the lower mass stars in 1645 01:12:50,380 --> 01:12:47,510 my talk I didn't touch on that too much 1646 01:12:52,090 --> 01:12:50,390 because they were so bright to Spitzer 1647 01:12:54,730 --> 01:12:52,100 that Spitzer actually couldn't image 1648 01:12:56,680 --> 01:12:54,740 them so we necessarily focused on kind 1649 01:12:59,050 --> 01:12:56,690 of a more outlying areas of Orion but 1650 01:13:00,490 --> 01:12:59,060 they're really responsible for just a 1651 01:13:03,400 --> 01:13:00,500 lot of what goes on in that central 1652 01:13:05,680 --> 01:13:03,410 region you know I'm learning a lot about 1653 01:13:08,860 --> 01:13:05,690 Orion as we did the visualizations of 1654 01:13:11,530 --> 01:13:08,870 the Orion Nebula and to see that giant 1655 01:13:13,810 --> 01:13:11,540 river of gas in behind it and recognize 1656 01:13:15,760 --> 01:13:13,820 that Terry yes this may be the city but 1657 01:13:20,290 --> 01:13:15,770 there is a tremendous number of suburbs 1658 01:13:23,770 --> 01:13:20,300 within the OMC out there that there's a 1659 01:13:25,810 --> 01:13:23,780 rich picture of star formation within 1660 01:13:38,550 --> 01:13:25,820 Orion is so much more than we think of 1661 01:13:40,690 --> 01:13:38,560 when we just think of the Orion Nebula I 1662 01:13:42,730 --> 01:13:40,700 may have missed it but what was the 1663 01:13:44,320 --> 01:13:42,740 mechanism for brightness changes that 1664 01:13:45,760 --> 01:13:44,330 quickly all right so what's the 1665 01:13:47,560 --> 01:13:45,770 mechanism for the quick brightness 1666 01:13:51,670 --> 01:13:47,570 changes within the t-tauri stars plot 1667 01:13:53,290 --> 01:13:51,680 you showed so if you remember that sort 1668 01:13:55,960 --> 01:13:53,300 of schematic I showed of how material 1669 01:13:59,740 --> 01:13:55,970 falls under the star exactly that's all 1670 01:14:02,260 --> 01:13:59,750 happening over about one tenth of the 1671 01:14:05,110 --> 01:14:02,270 earth-sun distance so a fairly small 1672 01:14:07,590 --> 01:14:05,120 region and just changes in the density 1673 01:14:10,300 --> 01:14:07,600 of the accreting material due to 1674 01:14:12,670 --> 01:14:10,310 pre-existing irregularities in the disk 1675 01:14:14,470 --> 01:14:12,680 structure can cause those brightness 1676 01:14:16,750 --> 01:14:14,480 variations the accretion rate sort of 1677 01:14:20,230 --> 01:14:16,760 goes up and down and that leads to 1678 01:14:29,560 --> 01:14:20,240 changes in the brightness other 1679 01:14:31,300 --> 01:14:29,570 questions yeah so what caused those 1680 01:14:33,689 --> 01:14:31,310 holes if that's really if Herschel 1681 01:14:37,379 --> 01:14:33,699 really is finding a hole 1682 01:14:38,969 --> 01:14:37,389 how did it get there that is probably 1683 01:14:41,699 --> 01:14:38,979 due to those outflows that I've been 1684 01:14:44,129 --> 01:14:41,709 talking about that some all of these 1685 01:14:47,310 --> 01:14:44,139 stars they accrete matter but then some 1686 01:14:49,500 --> 01:14:47,320 fraction of that is pushed off along the 1687 01:14:51,660 --> 01:14:49,510 poles of the star with some force and 1688 01:14:53,430 --> 01:14:51,670 that could actually blow holes in the 1689 01:14:55,259 --> 01:14:53,440 nebula if you have a few of them that 1690 01:14:57,810 --> 01:14:55,269 with the chance alignment so they're all 1691 01:15:03,089 --> 01:14:57,820 sort of collaborating on opening up a 1692 01:15:05,279 --> 01:15:03,099 hole in the nebula all right we got like 1693 01:15:05,879 --> 01:15:05,289 two more one here and one there and one 1694 01:15:17,339 --> 01:15:05,889 back there 1695 01:15:18,959 --> 01:15:17,349 that's three men all right so why do we 1696 01:15:21,390 --> 01:15:18,969 see this filament or river of gas 1697 01:15:23,370 --> 01:15:21,400 through Orion it seems like it's 1698 01:15:24,839 --> 01:15:23,380 probably magnetic fields that are 1699 01:15:26,879 --> 01:15:24,849 responsible for the filaments you've got 1700 01:15:29,250 --> 01:15:26,889 these large-scale magnetic fields kind 1701 01:15:34,020 --> 01:15:29,260 of threading the galaxies due to the 1702 01:15:35,759 --> 01:15:34,030 motion of hot gas and any gas that's 1703 01:15:38,100 --> 01:15:35,769 even a little bit ionized tends to 1704 01:15:39,479 --> 01:15:38,110 follow along those field lines so that 1705 01:15:42,870 --> 01:15:39,489 leads to these kind of stretched out 1706 01:15:54,359 --> 01:15:42,880 filamentary structures okay we had one 1707 01:15:56,339 --> 01:15:54,369 way in the back when a cloud of gas that 1708 01:15:57,569 --> 01:15:56,349 presented to a binary star with that 1709 01:16:00,719 --> 01:15:57,579 form gravity waves 1710 01:16:04,199 --> 01:16:00,729 all right so gravity waves detected from 1711 01:16:06,000 --> 01:16:04,209 two black holes merging together the 1712 01:16:08,310 --> 01:16:06,010 creation of these binary stars would 1713 01:16:11,779 --> 01:16:08,320 that also create binary gravitational 1714 01:16:15,120 --> 01:16:11,789 waves that summarize a question right 1715 01:16:17,100 --> 01:16:15,130 these are much lower energy events than 1716 01:16:19,379 --> 01:16:17,110 the creation than the collision of 1717 01:16:21,180 --> 01:16:19,389 binary black holes so there really 1718 01:16:24,089 --> 01:16:21,190 wouldn't be any appreciable gravity 1719 01:16:27,930 --> 01:16:24,099 waves from this it's more just this this 1720 01:16:30,089 --> 01:16:27,940 the clouds kind of quietly relatively 1721 01:16:33,870 --> 01:16:30,099 quietly collapsing into two stars on 1722 01:16:46,490 --> 01:16:33,880 their own okay who had the last question 1723 01:16:58,250 --> 01:16:55,480 the clustered beginner custard together 1724 01:17:00,050 --> 01:16:58,260 childhood under the impression we look 1725 01:17:02,120 --> 01:17:00,060 at a constellation up there what you 1726 01:17:03,470 --> 01:17:02,130 really see is a flat field and it'll 1727 01:17:04,960 --> 01:17:03,480 start one start moving here the other 1728 01:17:07,970 --> 01:17:04,970 maybe way to tell I'm not over there 1729 01:17:11,390 --> 01:17:07,980 when they just look like they're aligned 1730 01:17:13,490 --> 01:17:11,400 in a pattern you've seen of it right 1731 01:17:18,800 --> 01:17:13,500 there angular separation 1732 01:17:22,250 --> 01:17:18,810 visibly that's not true then or other 1733 01:17:25,490 --> 01:17:22,260 constellations those same stars kind of 1734 01:17:27,500 --> 01:17:25,500 grouped together okay so yeah the 1735 01:17:29,630 --> 01:17:27,510 question it is I when we look at 1736 01:17:32,900 --> 01:17:29,640 constellations in the night sky the 1737 01:17:35,090 --> 01:17:32,910 Stars the the full Orion constellation 1738 01:17:38,480 --> 01:17:35,100 like Betelgeuse and Rigel there are 1739 01:17:41,690 --> 01:17:38,490 totally different distances but so how 1740 01:17:43,040 --> 01:17:41,700 does that up does how does that 1741 01:17:45,290 --> 01:17:43,050 translate to some of this stuff we're 1742 01:17:47,030 --> 01:17:45,300 here working looking at here yeah so in 1743 01:17:48,740 --> 01:17:47,040 general if you pick some random 1744 01:17:50,690 --> 01:17:48,750 constellation out of the sky the stars 1745 01:17:52,040 --> 01:17:50,700 of that constellation have no physical 1746 01:17:54,470 --> 01:17:52,050 relationship to one another 1747 01:17:55,790 --> 01:17:54,480 Orion's kind of an exception is 1748 01:17:58,610 --> 01:17:55,800 everything I've been talking about here 1749 01:18:01,070 --> 01:17:58,620 this is a single well two really clouds 1750 01:18:03,740 --> 01:18:01,080 of molecular gas they're forming stars 1751 01:18:05,900 --> 01:18:03,750 that are in close proximity so all of 1752 01:18:07,760 --> 01:18:05,910 the young stars in Orion are physically 1753 01:18:10,190 --> 01:18:07,770 associated it's kind of an exception to 1754 01:18:12,380 --> 01:18:10,200 the usual rule about constellations well 1755 01:18:14,140 --> 01:18:12,390 also on the angular separation on the 1756 01:18:17,090 --> 01:18:14,150 sky of the stars of the constellation 1757 01:18:19,280 --> 01:18:17,100 are much much much much larger these are 1758 01:18:21,980 --> 01:18:19,290 all very close they're all basically in 1759 01:18:27,380 --> 01:18:21,990 Orion hanging down from Orion's belt in 1760 01:18:30,710 --> 01:18:27,390 this area down what you're talking about 1761 01:18:32,840 --> 01:18:30,720 the Magellanic Clouds no I'm not talking 1762 01:18:36,400 --> 01:18:32,850 about the Magellanic Clouds the Orion 1763 01:18:39,650 --> 01:18:36,410 the the star formation in Orion is all 1764 01:18:42,170 --> 01:18:39,660 in the area around the Orion Nebula down 1765 01:18:46,790 --> 01:18:42,180 from the below the belt you're hitting a 1766 01:18:51,569 --> 01:18:49,439 all right Hartman do you have one last 1767 01:18:54,299 --> 01:18:51,579 thing interesting I think I remember 1768 01:18:57,180 --> 01:18:54,309 right output of the three famous stars 1769 01:19:00,060 --> 01:18:57,190 in Orion's belt I'll attack although hi 1770 01:19:04,229 --> 01:19:00,070 millou taka 2,000 light-years away and 1771 01:19:06,390 --> 01:19:04,239 the end stars are like five hundred I 1772 01:19:08,040 --> 01:19:06,400 actually I guess oh he's talking about 1773 01:19:10,859 --> 01:19:08,050 that stars in the Bell being a totally 1774 01:19:14,009 --> 01:19:10,869 different distances yes I did a constant 1775 01:19:17,100 --> 01:19:14,019 I did a visualization of the main stars 1776 01:19:18,930 --> 01:19:17,110 of Orion in 3d and spin it around if you 1777 01:19:22,439 --> 01:19:18,940 look on youtube you can find it the 1778 01:19:25,770 --> 01:19:22,449 Orion constellation in 3d and it's one 1779 01:19:27,569 --> 01:19:25,780 of our more popular ones for educational 1780 01:19:29,250 --> 01:19:27,579 purposes because it takes a Ryan you see 1781 01:19:31,080 --> 01:19:29,260 it as it does and then you spin it 1782 01:19:32,759 --> 01:19:31,090 sideways and it looks more like a 1783 01:19:37,169 --> 01:19:32,769 stealth bomber than it does look like a 1784 01:19:41,069 --> 01:19:37,179 hundred all right let let's see next 1785 01:19:43,819 --> 01:19:41,079 month is it's June so July I forget what 1786 01:19:46,560 --> 01:19:43,829 our time oh the Milky Way bulge the blob 1787 01:19:49,770 --> 01:19:46,570 from from blob - remarkably detailed 1788 01:19:52,169 --> 01:19:49,780 picture that will be our July talk hope 1789 01:19:53,480 --> 01:19:52,179 to see you all there and let's give will 1790 01:20:04,460 --> 01:19:53,490 another big