1 00:00:05,630 --> 00:00:02,990 speed and in the background grant who's 2 00:00:07,610 --> 00:00:05,640 sitting probably you know twenty offices 3 00:00:09,290 --> 00:00:07,620 down that way is taking it and sending 4 00:00:15,620 --> 00:00:09,300 out to youtube so let's give grant a 5 00:00:17,480 --> 00:00:15,630 hand and thank him we got the lights you 6 00:00:23,540 --> 00:00:17,490 can bring lights down we'll set and 7 00:00:25,609 --> 00:00:23,550 we'll get ourselves started good evening 8 00:00:28,009 --> 00:00:25,619 ladies and gentlemen and welcome to the 9 00:00:30,950 --> 00:00:28,019 Space Telescope public lecture series it 10 00:00:33,020 --> 00:00:30,960 is my pleasure to host tonight I am dr. 11 00:00:43,639 --> 00:00:33,030 Frank summers of the office of public 12 00:00:46,819 --> 00:00:43,649 outreach and it's so when you come in on 13 00:00:47,389 --> 00:00:46,829 the tables we have lithographs pictures 14 00:00:50,000 --> 00:00:47,399 from Hubble 15 00:00:52,250 --> 00:00:50,010 tonight's picture is Nessie a 104 16 00:00:54,470 --> 00:00:52,260 there's some gray row galaxies and I 17 00:00:57,229 --> 00:00:54,480 chose it because it has a very large 18 00:00:59,450 --> 00:00:57,239 central region that's the Bulge of a 19 00:01:02,020 --> 00:00:59,460 galaxy and you're gonna learn about the 20 00:01:04,399 --> 00:01:02,030 Bulge of the Milky Way galaxy tonight 21 00:01:06,800 --> 00:01:04,409 tonight's speaker is talking on the 22 00:01:10,070 --> 00:01:06,810 Milky Way's bulge from a hypothesized 23 00:01:12,560 --> 00:01:10,080 blob to a remarkably detailed picture 24 00:01:14,719 --> 00:01:12,570 okay so you have an example of a bulge 25 00:01:18,920 --> 00:01:14,729 in front of you to reference while he 26 00:01:21,350 --> 00:01:18,930 gives his talk next month 27 00:01:23,510 --> 00:01:21,360 Greg Sloan will be talking about ashes 28 00:01:27,140 --> 00:01:23,520 to ashes dust to dust 29 00:01:28,910 --> 00:01:27,150 the fate of stars like the Sun so he 30 00:01:30,950 --> 00:01:28,920 specifically said he's not going to talk 31 00:01:33,770 --> 00:01:30,960 about exploding stars and black holes 32 00:01:36,200 --> 00:01:33,780 and neutron stars is that's that's 33 00:01:39,499 --> 00:01:36,210 another talk he's gonna talk about what 34 00:01:42,319 --> 00:01:39,509 happens to medium star sized stars like 35 00:01:42,710 --> 00:01:42,329 our Sun and the ashes to ashes dust to 36 00:01:45,440 --> 00:01:42,720 dust 37 00:01:48,859 --> 00:01:45,450 is a clue okay so come back in August 38 00:01:51,620 --> 00:01:48,869 for that in September we will talk about 39 00:01:56,899 --> 00:01:51,630 more death we're just being morbid here 40 00:02:00,249 --> 00:01:56,909 and our astronomy 100 ways to die in the 41 00:02:03,109 --> 00:02:00,259 universe that's Katie Katie a lot hello 42 00:02:05,209 --> 00:02:03,119 close to be talking about that and in 43 00:02:07,340 --> 00:02:05,219 October then we'll get to those 44 00:02:11,260 --> 00:02:07,350 exploding stars will talk about chasing 45 00:02:13,510 --> 00:02:11,270 supernovae with Kepler from Gotham 46 00:02:15,430 --> 00:02:13,520 here at Space Telescope if you would 47 00:02:17,740 --> 00:02:15,440 like to information about these you can 48 00:02:19,990 --> 00:02:17,750 go to our website go to your favorite 49 00:02:21,970 --> 00:02:20,000 search engine type in Space Telescope 50 00:02:25,330 --> 00:02:21,980 public lectures you should find this 51 00:02:28,320 --> 00:02:25,340 webpage with our upcoming lectures 52 00:02:32,980 --> 00:02:28,330 listed here the links to our live 53 00:02:35,530 --> 00:02:32,990 webcasting as well as our archive the 54 00:02:38,410 --> 00:02:35,540 youtube playlist goes back to 2014 and 55 00:02:42,460 --> 00:02:38,420 the STScI webcast archive goes all the 56 00:02:44,320 --> 00:02:42,470 way back to 2005 so there's an awful lot 57 00:02:47,320 --> 00:02:44,330 if you want to binge-watch astronomy 58 00:02:50,800 --> 00:02:47,330 lectures I got it an entire week of it 59 00:02:52,480 --> 00:02:50,810 for you okay actually I realized that 60 00:02:55,600 --> 00:02:52,490 you know tonight is probably about my 61 00:03:02,420 --> 00:02:55,610 16th anniversary hosting these public 62 00:03:08,450 --> 00:03:05,330 you know it's been a lot of fun but Wow 63 00:03:10,910 --> 00:03:08,460 sixteen years all right if you would 64 00:03:13,010 --> 00:03:10,920 like to have notice about these public 65 00:03:15,770 --> 00:03:13,020 lectures you can sign up by providing 66 00:03:17,870 --> 00:03:15,780 your email here to our announcements we 67 00:03:19,850 --> 00:03:17,880 send out like two or three announcements 68 00:03:21,890 --> 00:03:19,860 a month 69 00:03:25,100 --> 00:03:21,900 yes announcements sign up at the website 70 00:03:26,570 --> 00:03:25,110 or if you can't handle online technology 71 00:03:29,780 --> 00:03:26,580 what are you doing asking for an email 72 00:03:31,160 --> 00:03:29,790 but anyways just give me your email 73 00:03:34,040 --> 00:03:31,170 address write it down a piece of paper 74 00:03:35,900 --> 00:03:34,050 and I'll make sure to add you okay if 75 00:03:38,180 --> 00:03:35,910 also you have comments or questions you 76 00:03:42,590 --> 00:03:38,190 can send them to our email public 77 00:03:45,590 --> 00:03:42,600 lecture at STScI dot edu if you are into 78 00:03:48,440 --> 00:03:45,600 social media we have a variety for the 79 00:03:50,990 --> 00:03:48,450 hubble web and Space Telescope on 80 00:03:53,180 --> 00:03:51,000 Facebook Twitter YouTube Instagram and 81 00:03:56,000 --> 00:03:53,190 probably a few others that I'm not 82 00:03:58,699 --> 00:03:56,010 listing here I myself am on Facebook 83 00:04:01,490 --> 00:03:58,709 Google+ and Twitter every now and then 84 00:04:05,180 --> 00:04:01,500 if you want to hear more from me 85 00:04:08,990 --> 00:04:05,190 let's see Observatory I had did not get 86 00:04:10,900 --> 00:04:09,000 an email before I started this it was 87 00:04:13,580 --> 00:04:10,910 sort of cloudy and sort of not cloudy 88 00:04:14,330 --> 00:04:13,590 actually when I left my houses to come 89 00:04:16,670 --> 00:04:14,340 in this evening 90 00:04:19,670 --> 00:04:16,680 it was raining but it was sunny while it 91 00:04:20,930 --> 00:04:19,680 was raining so I'm not sure what they 92 00:04:24,140 --> 00:04:20,940 were gonna do so that's still a question 93 00:04:25,909 --> 00:04:24,150 mark I will check with aready during the 94 00:04:29,690 --> 00:04:25,919 lecture and I'll have an answer by the 95 00:04:31,880 --> 00:04:29,700 end of the lecture okay but if you are 96 00:04:33,890 --> 00:04:31,890 not if if it doesn't happen tonight 97 00:04:36,890 --> 00:04:33,900 remember there are still open houses on 98 00:04:38,870 --> 00:04:36,900 Friday evenings this webpage of the 99 00:04:42,409 --> 00:04:38,880 Maryland Space Grant observatory will 100 00:04:42,950 --> 00:04:42,419 list the observatory status every Friday 101 00:04:45,560 --> 00:04:42,960 evening 102 00:04:46,670 --> 00:04:45,570 about 5:30 6 o'clock they will list the 103 00:04:48,320 --> 00:04:46,680 status whether or not they're gonna be 104 00:04:53,480 --> 00:04:48,330 open so if you don't get a chance 105 00:04:58,180 --> 00:04:53,490 tonight check back on Friday and now the 106 00:05:00,800 --> 00:04:58,190 news from the universe for July 2018 and 107 00:05:01,190 --> 00:05:00,810 unfortunately I have a repeat story for 108 00:05:06,580 --> 00:05:01,200 you tonight 109 00:05:10,270 --> 00:05:06,590 and it is j DST launched delay ok so 110 00:05:13,650 --> 00:05:10,280 last time back in 111 00:05:16,180 --> 00:05:13,660 let's see when was it it was in March 112 00:05:18,940 --> 00:05:16,190 March or April or May one of those about 113 00:05:21,850 --> 00:05:18,950 three months ago okay the status of it 114 00:05:25,270 --> 00:05:21,860 was that it was being delayed until May 115 00:05:27,520 --> 00:05:25,280 2020 they had formed an independent 116 00:05:29,530 --> 00:05:27,530 review board to look at Jerez t's 117 00:05:32,380 --> 00:05:29,540 construction and really go through the 118 00:05:34,600 --> 00:05:32,390 process rigorously and especially to do 119 00:05:36,160 --> 00:05:34,610 a new cost analysis to make sure that 120 00:05:36,730 --> 00:05:36,170 they really knew what it was going to 121 00:05:38,920 --> 00:05:36,740 cost 122 00:05:41,830 --> 00:05:38,930 well that independent review board has 123 00:05:44,970 --> 00:05:41,840 now finished its study and the press 124 00:05:48,160 --> 00:05:44,980 release from last week was that they 125 00:05:51,040 --> 00:05:48,170 have a new launch date for web of March 126 00:05:52,870 --> 00:05:51,050 30th 2021 so that's almost that's 127 00:05:55,870 --> 00:05:52,880 another ten months of delay for the 128 00:05:57,670 --> 00:05:55,880 James Webb Space Telescope why well 129 00:06:00,070 --> 00:05:57,680 there are changes in the schedule due to 130 00:06:02,170 --> 00:06:00,080 environmental testing and work 131 00:06:05,590 --> 00:06:02,180 performance challenges on the spacecraft 132 00:06:07,900 --> 00:06:05,600 Sun shield and propulsion system okay 133 00:06:10,810 --> 00:06:07,910 that's technical technical language of 134 00:06:12,700 --> 00:06:10,820 the environmental testing I believe is 135 00:06:14,950 --> 00:06:12,710 the vacuum chamber testing that they did 136 00:06:17,140 --> 00:06:14,960 down at Johnson yeah and so they need 137 00:06:20,080 --> 00:06:17,150 more time to pass all of those tests and 138 00:06:21,730 --> 00:06:20,090 get things together but however the 139 00:06:23,440 --> 00:06:21,740 independent review board I mean this is 140 00:06:25,900 --> 00:06:23,450 independent this is not a NASA board 141 00:06:27,640 --> 00:06:25,910 this is independent of NASA it came back 142 00:06:30,040 --> 00:06:27,650 and they also reaffirmed Webb 143 00:06:32,620 --> 00:06:30,050 significant complexity incredible 144 00:06:34,780 --> 00:06:32,630 scientific potential and importance to 145 00:06:36,760 --> 00:06:34,790 astrophysics okay so they didn't say 146 00:06:38,530 --> 00:06:36,770 like oh no no this is a problem no they 147 00:06:41,260 --> 00:06:38,540 said look this is really important and 148 00:06:44,080 --> 00:06:41,270 we gotta get it right okay we do not 149 00:06:46,150 --> 00:06:44,090 have any chance of servicing the James 150 00:06:48,219 --> 00:06:46,160 Webb Space Telescope you're gonna get it 151 00:06:50,830 --> 00:06:48,229 right the first time so that's basically 152 00:06:54,550 --> 00:06:50,840 they said and the new development cost 153 00:06:55,990 --> 00:06:54,560 estimate is 8.8 billion and for those of 154 00:06:58,240 --> 00:06:56,000 you who remember what I said a few 155 00:07:00,640 --> 00:06:58,250 months ago the development cost estimate 156 00:07:05,620 --> 00:07:00,650 originally was eight billion so this in 157 00:07:09,219 --> 00:07:05,630 and a 10% increase in that okay and 158 00:07:12,070 --> 00:07:09,229 that's basically the summary of the the 159 00:07:13,900 --> 00:07:12,080 press release we are of course 160 00:07:15,909 --> 00:07:13,910 disappointed that we'll have to wait 161 00:07:18,649 --> 00:07:15,919 longer for the science from the James 162 00:07:21,570 --> 00:07:18,659 Webb Space Telescope but 163 00:07:23,909 --> 00:07:21,580 it's the next great observatory okay 164 00:07:25,800 --> 00:07:23,919 it's gonna do things that Hubble can't 165 00:07:28,709 --> 00:07:25,810 do that no other Space Telescope has 166 00:07:30,929 --> 00:07:28,719 ever been able to do it's highly 167 00:07:31,770 --> 00:07:30,939 technical and as they say it's gonna be 168 00:07:33,659 --> 00:07:31,780 worth waiting for 169 00:07:36,990 --> 00:07:33,669 okay let's make sure we get it done 170 00:07:44,339 --> 00:07:37,000 right all right our second story tonight 171 00:07:51,209 --> 00:07:44,349 is it came from outer space I am talking 172 00:07:56,249 --> 00:07:51,219 about yet another update the the object 173 00:07:59,580 --> 00:07:56,259 called a 2017 u1 also now called 174 00:08:03,270 --> 00:07:59,590 omoi this is the orbit when it was 175 00:08:04,760 --> 00:08:03,280 discovered in October 25th to actually 176 00:08:07,830 --> 00:08:04,770 discovered a little bit before was in 177 00:08:11,070 --> 00:08:07,840 2017 by the pan-starrs Observatory 178 00:08:14,129 --> 00:08:11,080 alright and if I pull back you can see 179 00:08:16,379 --> 00:08:14,139 this is the full path of it and what 180 00:08:22,019 --> 00:08:16,389 makes this special which makes this u1 181 00:08:25,649 --> 00:08:22,029 okay is that this object path is unbound 182 00:08:28,950 --> 00:08:25,659 to the Sun indicating that it's not part 183 00:08:32,399 --> 00:08:28,960 of our solar system it came from outer 184 00:08:36,300 --> 00:08:32,409 space yes this is the first confirmed 185 00:08:38,969 --> 00:08:36,310 object that trajectory comes from 186 00:08:40,469 --> 00:08:38,979 interstellar space all right and there 187 00:08:41,699 --> 00:08:40,479 probably have been many of these that 188 00:08:43,649 --> 00:08:41,709 come through our solar system this is 189 00:08:46,889 --> 00:08:43,659 the first one we've seen and confirmed 190 00:08:49,740 --> 00:08:46,899 and when I told you about this last fall 191 00:08:52,710 --> 00:08:49,750 I showed you that hey this is all we can 192 00:08:54,900 --> 00:08:52,720 see it yeah that tiny little dot there 193 00:08:56,040 --> 00:08:54,910 that the arrow is pointing to that's 194 00:08:59,280 --> 00:08:56,050 omar Moya 195 00:09:02,189 --> 00:08:59,290 alright so it's really small okay it's 196 00:09:05,069 --> 00:09:02,199 only about half a mile in size and 197 00:09:07,290 --> 00:09:05,079 that's just an estimate okay and we're 198 00:09:09,870 --> 00:09:07,300 looking at and so we really can track it 199 00:09:12,420 --> 00:09:09,880 but you need high precision telescopes 200 00:09:15,569 --> 00:09:12,430 to track it G where would we have a high 201 00:09:17,490 --> 00:09:15,579 precision telescope yes Hubble has 202 00:09:20,910 --> 00:09:17,500 helped the other thing that we noticed 203 00:09:22,560 --> 00:09:20,920 about it is also that it had brightness 204 00:09:24,480 --> 00:09:22,570 variations periodic brightness 205 00:09:28,019 --> 00:09:24,490 variations indicating that it was 206 00:09:30,150 --> 00:09:28,029 rotating and very likely was very 207 00:09:32,460 --> 00:09:30,160 elongated wasn't like a round object 208 00:09:33,810 --> 00:09:32,470 okay if a round object rotates you 209 00:09:36,630 --> 00:09:33,820 don't get these strong brightness 210 00:09:38,130 --> 00:09:36,640 variations but a elongated object 211 00:09:41,100 --> 00:09:38,140 rotates you get these strong brightness 212 00:09:42,600 --> 00:09:41,110 variations so what we knew about it last 213 00:09:43,950 --> 00:09:42,610 time I talked about it is that its orbit 214 00:09:46,680 --> 00:09:43,960 is consistent with an interstellar 215 00:09:48,570 --> 00:09:46,690 origin it rotates about every seven 216 00:09:51,600 --> 00:09:48,580 point three hours and there are these 217 00:09:55,410 --> 00:09:51,610 large brightness variations what we 218 00:09:57,900 --> 00:09:55,420 didn't know back then was it sighs you 219 00:10:00,060 --> 00:09:57,910 know about half a kilometer the axis 220 00:10:04,020 --> 00:10:00,070 ratio was at three to one or was it ten 221 00:10:06,090 --> 00:10:04,030 to one the color and the amount of 222 00:10:09,060 --> 00:10:06,100 reflectivity which is called the albedo 223 00:10:10,830 --> 00:10:09,070 the measurements appeared to disagree we 224 00:10:13,400 --> 00:10:10,840 didn't know it was composed of is it 225 00:10:17,280 --> 00:10:13,410 more asteroid like is it more comet-like 226 00:10:18,930 --> 00:10:17,290 and this is only the first one of this 227 00:10:20,880 --> 00:10:18,940 group what are they what are 228 00:10:23,190 --> 00:10:20,890 interstellar objects generally like and 229 00:10:24,000 --> 00:10:23,200 I finished with this slide to be 230 00:10:27,300 --> 00:10:24,010 continued 231 00:10:29,040 --> 00:10:27,310 tonight we continue the story tonight 232 00:10:32,000 --> 00:10:29,050 I'm going to show you an artist 233 00:10:36,630 --> 00:10:32,010 rendition of what oh mama look like on 234 00:10:39,600 --> 00:10:36,640 January 2nd 2018 so this is the artist 235 00:10:43,440 --> 00:10:39,610 rendition of omoi here on the left on 236 00:10:46,530 --> 00:10:43,450 January second 2018 and how do I know 237 00:10:49,080 --> 00:10:46,540 it's January 2nd 2018 because you see 238 00:10:51,870 --> 00:10:49,090 those positions of those planets yeah I 239 00:10:54,900 --> 00:10:51,880 calculated them okay I made sure that 240 00:10:57,810 --> 00:10:54,910 we're aware more was we got the planets 241 00:10:59,040 --> 00:10:57,820 right in the back I also calculated the 242 00:11:02,250 --> 00:10:59,050 position of the stars in the background 243 00:11:04,830 --> 00:11:02,260 okay so this is the star Spica in the 244 00:11:06,510 --> 00:11:04,840 constellation Virgo okay so not only are 245 00:11:09,060 --> 00:11:06,520 the planets in the right place the stars 246 00:11:11,040 --> 00:11:09,070 are in mostly right place I can't say 247 00:11:12,210 --> 00:11:11,050 it's absolutely the right place okay due 248 00:11:14,490 --> 00:11:12,220 to various things we did with the 249 00:11:17,550 --> 00:11:14,500 artistic aspect of it but you know all 250 00:11:20,100 --> 00:11:17,560 right so this is relatively scientific 251 00:11:22,980 --> 00:11:20,110 in being at art we try to try to combine 252 00:11:25,110 --> 00:11:22,990 science and art here okay and then you 253 00:11:27,570 --> 00:11:25,120 can see that there's all sorts of fuzz 254 00:11:32,340 --> 00:11:27,580 around it okay in these Jay jets coming 255 00:11:35,280 --> 00:11:32,350 out of it and that is the real story so 256 00:11:38,550 --> 00:11:35,290 in watching OMA more over the past 257 00:11:41,130 --> 00:11:38,560 several months Kay and basically the the 258 00:11:44,580 --> 00:11:41,140 observations ended in Jinbo January they 259 00:11:46,500 --> 00:11:44,590 found that its orbit deviated 260 00:11:49,410 --> 00:11:46,510 what would be expected just due to 261 00:11:53,100 --> 00:11:49,420 gravity now gravity is a solved problem 262 00:11:56,280 --> 00:11:53,110 we know how to solve gravity so if an 263 00:11:59,340 --> 00:11:56,290 object moves off of a path that gravity 264 00:12:02,130 --> 00:11:59,350 would predict some other forces involved 265 00:12:03,870 --> 00:12:02,140 okay so there's just a slight 266 00:12:06,000 --> 00:12:03,880 acceleration but we can measure these 267 00:12:08,640 --> 00:12:06,010 slight accelerations and it could be 268 00:12:10,530 --> 00:12:08,650 caused by jets of outgassing all right 269 00:12:15,210 --> 00:12:10,540 and that would be the ices near the 270 00:12:18,060 --> 00:12:15,220 surface spewing out as it passes by the 271 00:12:20,040 --> 00:12:18,070 Sun and heats up okay and so that's why 272 00:12:22,260 --> 00:12:20,050 you can see there are jets here in this 273 00:12:25,230 --> 00:12:22,270 artist's illustration pointing towards 274 00:12:27,840 --> 00:12:25,240 the Sun that would add a small force 275 00:12:30,120 --> 00:12:27,850 that would cause a deviation in the 276 00:12:33,270 --> 00:12:30,130 orbit this is similar to what we see for 277 00:12:36,390 --> 00:12:33,280 comets in our solar system however the 278 00:12:39,510 --> 00:12:36,400 important point to note is that no 279 00:12:41,220 --> 00:12:39,520 outgassing was observed which causes a 280 00:12:43,950 --> 00:12:41,230 little bit of a problem so you need some 281 00:12:47,670 --> 00:12:43,960 outgassing to create the orbit deviation 282 00:12:49,440 --> 00:12:47,680 but not so much outgassing that it would 283 00:12:52,170 --> 00:12:49,450 actually be observed by the telescopes 284 00:12:54,660 --> 00:12:52,180 that looked at it there's still lots of 285 00:12:56,490 --> 00:12:54,670 uncertainty here we still don't have 286 00:12:58,650 --> 00:12:56,500 great estimates we still only have 287 00:13:00,960 --> 00:12:58,660 estimates of the size the shape and the 288 00:13:03,060 --> 00:13:00,970 composition but if this outgassing is 289 00:13:06,600 --> 00:13:03,070 true then it's probably more comet-like 290 00:13:08,220 --> 00:13:06,610 than it is asteroid like and 291 00:13:09,900 --> 00:13:08,230 unfortunately we're not going to get any 292 00:13:12,120 --> 00:13:09,910 more observations because now it's out 293 00:13:14,760 --> 00:13:12,130 past the orbit of Jupiter and heading 294 00:13:20,370 --> 00:13:14,770 out of the solar system never to be seen 295 00:13:23,370 --> 00:13:20,380 again so where do we go from here on 296 00:13:26,910 --> 00:13:23,380 this there should be other interstellar 297 00:13:30,180 --> 00:13:26,920 interlopers in our future if there's one 298 00:13:32,760 --> 00:13:30,190 there's got to be more right and now we 299 00:13:34,680 --> 00:13:32,770 know that there is a population we will 300 00:13:36,530 --> 00:13:34,690 continue to look for them I sort of 301 00:13:39,900 --> 00:13:36,540 think of it like the Kuiper belt objects 302 00:13:42,270 --> 00:13:39,910 when we saw the first recognizable 303 00:13:43,800 --> 00:13:42,280 Kuiper belt objects in 1993 we started 304 00:13:45,930 --> 00:13:43,810 searching and searching for more and 305 00:13:47,790 --> 00:13:45,940 more and we developed a whole family 306 00:13:49,860 --> 00:13:47,800 hopefully over the next year's and 307 00:13:51,930 --> 00:13:49,870 decades will develop a whole family of 308 00:13:54,060 --> 00:13:51,940 these interstellar objects and we'll be 309 00:13:56,700 --> 00:13:54,070 able to understand the characteristics 310 00:13:58,100 --> 00:13:56,710 of a population one is just an 311 00:14:00,019 --> 00:13:58,110 interesting object 312 00:14:02,449 --> 00:14:00,029 until you have a dozen or so then you 313 00:14:04,160 --> 00:14:02,459 can't really make group statements so we 314 00:14:04,819 --> 00:14:04,170 look forward to more interstellar 315 00:14:06,650 --> 00:14:04,829 visitors 316 00:14:08,449 --> 00:14:06,660 I wish they'd hang around a little bit 317 00:14:09,530 --> 00:14:08,459 longer but the nature of their orbits 318 00:14:11,630 --> 00:14:09,540 means that they're gonna come through 319 00:14:14,530 --> 00:14:11,640 BAM we get about six months of observing 320 00:14:18,590 --> 00:14:14,540 and then they're gone forever all right 321 00:14:22,579 --> 00:14:18,600 finally our third story a ten million 322 00:14:25,850 --> 00:14:22,589 year old baby this just hit the news 323 00:14:27,680 --> 00:14:25,860 wires today okay and I could not stop 324 00:14:29,990 --> 00:14:27,690 myself from adding it to the public 325 00:14:35,000 --> 00:14:30,000 lectures the presentation all right so 326 00:14:35,960 --> 00:14:35,010 this somewhere in here is the star PDS 327 00:14:38,030 --> 00:14:35,970 70 328 00:14:40,519 --> 00:14:38,040 I'd love to point out the exact star but 329 00:14:41,750 --> 00:14:40,529 they didn't tell us in when they when 330 00:14:43,579 --> 00:14:41,760 they put out this image they said oh 331 00:14:45,860 --> 00:14:43,589 it's in the center well this is the 332 00:14:48,920 --> 00:14:45,870 center I don't know exactly which one it 333 00:14:51,829 --> 00:14:48,930 is all right and so the star PDS 70 is 334 00:14:54,470 --> 00:14:51,839 special it's you know well first of all 335 00:14:56,660 --> 00:14:54,480 it's an ordinary case five star but it's 336 00:14:59,690 --> 00:14:56,670 only ten million years old it's a young 337 00:15:00,889 --> 00:14:59,700 star it's a recently formed star okay 338 00:15:10,790 --> 00:15:00,899 all right 339 00:15:13,220 --> 00:15:10,800 blocking out a little bit of the light 340 00:15:14,990 --> 00:15:13,230 from the Sun with this coal tting spot 341 00:15:17,030 --> 00:15:15,000 you'll notice there'll be a black circle 342 00:15:19,040 --> 00:15:17,040 at the center of all these images that's 343 00:15:20,389 --> 00:15:19,050 not because there's nothing there it's 344 00:15:22,400 --> 00:15:20,399 because we're actually blocking it out 345 00:15:25,120 --> 00:15:22,410 that black circle is blocking the light 346 00:15:28,009 --> 00:15:25,130 from the star okay so here's the star 347 00:15:29,060 --> 00:15:28,019 here's a potential companion that they 348 00:15:31,310 --> 00:15:29,070 identified okay 349 00:15:32,720 --> 00:15:31,320 and when they analyzed this and did all 350 00:15:36,050 --> 00:15:32,730 sorts of computer process you can pulled 351 00:15:38,480 --> 00:15:36,060 it out they found that first of all that 352 00:15:41,660 --> 00:15:38,490 this star was a brown dwarf that could 353 00:15:44,720 --> 00:15:41,670 be a companion all right and then they 354 00:15:47,090 --> 00:15:44,730 found a disk of material orbiting around 355 00:15:49,519 --> 00:15:47,100 the star all right so you're seeing an 356 00:15:51,079 --> 00:15:49,529 disc of material edge on right so you're 357 00:15:54,310 --> 00:15:51,089 seeing material orbiting around the star 358 00:15:56,900 --> 00:15:54,320 plus a jet of material spewing out 359 00:15:58,490 --> 00:15:56,910 perpendicular to the disk and we see 360 00:16:00,920 --> 00:15:58,500 this in other places for example in 361 00:16:03,170 --> 00:16:00,930 Orion when we see newborn stars okay we 362 00:16:07,069 --> 00:16:03,180 have discs and we have jets all right 363 00:16:09,350 --> 00:16:07,079 and so this was interesting and there 364 00:16:11,630 --> 00:16:09,360 were strong hints that a giant planet 365 00:16:14,510 --> 00:16:11,640 could have formed in the interior 366 00:16:16,730 --> 00:16:14,520 and the inner parts of the disc they 367 00:16:19,760 --> 00:16:16,740 went back and studied this again over 368 00:16:22,640 --> 00:16:19,770 time and in 2012 they released this 369 00:16:25,310 --> 00:16:22,650 image again this black spot is just the 370 00:16:27,260 --> 00:16:25,320 occulting circle to get rid of this 371 00:16:30,230 --> 00:16:27,270 flight of the star but you can see how 372 00:16:33,170 --> 00:16:30,240 there's a bright ring here and inside 373 00:16:36,680 --> 00:16:33,180 the ring is an empty region okay there's 374 00:16:38,900 --> 00:16:36,690 a gap that's about 140 astronomical 375 00:16:41,390 --> 00:16:38,910 units across and if you don't remember 376 00:16:44,300 --> 00:16:41,400 an astronomical unit is one the distance 377 00:16:47,060 --> 00:16:44,310 from Earth to the Sun Neptune is about 378 00:16:48,920 --> 00:16:47,070 30 astronomical units and radius so this 379 00:16:52,070 --> 00:16:48,930 is a hundred and forty astronomical 380 00:16:54,590 --> 00:16:52,080 units okay and so there is a gap in 381 00:16:57,890 --> 00:16:54,600 there and that really says hey if 382 00:17:00,020 --> 00:16:57,900 there's a giant planet in there or more 383 00:17:02,930 --> 00:17:00,030 one or more giant planets that can clear 384 00:17:06,980 --> 00:17:02,940 out that gap well that sets the stage 385 00:17:08,960 --> 00:17:06,990 for what was just announced in 2018 they 386 00:17:11,270 --> 00:17:08,970 got a picture from the Very Large 387 00:17:13,939 --> 00:17:11,280 Telescope yes that is its name 388 00:17:15,020 --> 00:17:13,949 the Very Large Telescope we astronomers 389 00:17:17,600 --> 00:17:15,030 are pretty straightforward 390 00:17:23,180 --> 00:17:17,610 from the European Southern Observatory 391 00:17:28,760 --> 00:17:23,190 the VLT got that image you can see the 392 00:17:31,570 --> 00:17:28,770 gap and you can see that ladies and 393 00:17:39,220 --> 00:17:31,580 gentlemen this is the first confirmed 394 00:17:45,430 --> 00:17:40,650 [Music] 395 00:17:47,170 --> 00:17:45,440 this planet is called PDS 70 B the 396 00:17:49,540 --> 00:17:47,180 lowercase B indicating that it's a 397 00:17:52,840 --> 00:17:49,550 planet it's about 20 astronomical units 398 00:17:56,110 --> 00:17:52,850 from its star it is a few Jupiter masses 399 00:17:58,030 --> 00:17:56,120 so only 2 or 3 or 4 Jupiter masses all 400 00:18:01,720 --> 00:17:58,040 right so it's Jupiter size it's a gas 401 00:18:05,170 --> 00:18:01,730 giant planet it's very hot okay 402 00:18:07,870 --> 00:18:05,180 1,800 degrees Fahrenheit all right for 403 00:18:09,580 --> 00:18:07,880 example the the cloud tops of Jupiter or 404 00:18:12,400 --> 00:18:09,590 minus a hundred degrees Fahrenheit as 405 00:18:15,850 --> 00:18:12,410 such all right this is still in 406 00:18:18,400 --> 00:18:15,860 formation okay at 10 million years old 407 00:18:21,310 --> 00:18:18,410 this is the 10 million year old baby I 408 00:18:23,770 --> 00:18:21,320 was talking about in the title ok and 409 00:18:25,870 --> 00:18:23,780 when they do further analysis on it and 410 00:18:29,110 --> 00:18:25,880 they really study it they can tell that 411 00:18:30,640 --> 00:18:29,120 its atmosphere is cloudy I can't tell 412 00:18:32,950 --> 00:18:30,650 you how because I didn't have enough 413 00:18:35,230 --> 00:18:32,960 time to read all the papers today too I 414 00:18:38,080 --> 00:18:35,240 think but as one of the results that 415 00:18:41,140 --> 00:18:38,090 they came out from it so we have had 416 00:18:43,570 --> 00:18:41,150 pictures of planets and such but this is 417 00:18:47,410 --> 00:18:43,580 a newborn planet it takes approximately 418 00:18:50,950 --> 00:18:47,420 10 million years for a gas giant to form 419 00:18:54,070 --> 00:18:50,960 so this is really just a newborn gas 420 00:18:57,010 --> 00:18:54,080 giant and it's a really cool result that 421 00:18:59,200 --> 00:18:57,020 just got announced today all right so I 422 00:19:01,180 --> 00:18:59,210 like to bring you the the really cool 423 00:19:03,060 --> 00:19:01,190 results as they come even though this 424 00:19:06,060 --> 00:19:03,070 isn't a Hubble or a Space Telescope 425 00:19:10,620 --> 00:19:06,070 story it was just too important to skip 426 00:19:15,280 --> 00:19:10,630 and that's our news from the universe 427 00:19:18,420 --> 00:19:15,290 our featured speaker tonight is David 428 00:19:23,110 --> 00:19:18,430 Netto from the Johns Hopkins University 429 00:19:26,800 --> 00:19:23,120 he did his PhD work at the Ohio State 430 00:19:28,870 --> 00:19:26,810 University and then did a postdoc down 431 00:19:31,570 --> 00:19:28,880 in Australia although you he says he 432 00:19:34,630 --> 00:19:31,580 originally hails from Canada came to the 433 00:19:36,940 --> 00:19:34,640 u.s. to do the the PhD went to Australia 434 00:19:38,440 --> 00:19:36,950 to do a postdoc and fortunately came 435 00:19:40,720 --> 00:19:38,450 back to the u.s. to the Johns Hopkins 436 00:19:43,810 --> 00:19:40,730 University and he holds the Davis post 437 00:19:46,420 --> 00:19:43,820 starbuck post doctoral fellowship across 438 00:19:50,290 --> 00:19:46,430 the way he'll tell you about his 439 00:19:52,720 --> 00:19:50,300 research but he says that in his in his 440 00:19:55,510 --> 00:19:52,730 spare time when he's not doing research 441 00:19:57,010 --> 00:19:55,520 he works with the summer interns that 442 00:19:58,270 --> 00:19:57,020 the high school and college students 443 00:20:01,030 --> 00:19:58,280 that come in and work with us over the 444 00:20:05,220 --> 00:20:01,040 summer and he's also can be found down 445 00:20:21,340 --> 00:20:05,230 at the SPCA walking the dogs 446 00:20:23,050 --> 00:20:21,350 ladies gentlemen David natal thank you 447 00:20:26,080 --> 00:20:23,060 for the introduction Frank can everyone 448 00:20:27,940 --> 00:20:26,090 hear me all right good all right so I'll 449 00:20:30,340 --> 00:20:27,950 be speaking about the Milky Way's bulge 450 00:20:33,550 --> 00:20:30,350 and I'll explain what a ball just 451 00:20:35,140 --> 00:20:33,560 shortly but you can see one in the image 452 00:20:37,270 --> 00:20:35,150 that was given out earlier that's the 453 00:20:40,540 --> 00:20:37,280 sombrero galaxy a relatively famous 454 00:20:43,480 --> 00:20:40,550 galaxy and that is a spectacular image 455 00:20:46,720 --> 00:20:43,490 of a galaxy which is a combination of a 456 00:20:51,850 --> 00:20:46,730 disc and a bulge somewhat similar to the 457 00:20:54,280 --> 00:20:51,860 Milky Way but not quite this is an image 458 00:20:58,090 --> 00:20:54,290 that'll look very familiar to people who 459 00:20:59,740 --> 00:20:58,100 have gone camping and maybe not familiar 460 00:21:02,350 --> 00:20:59,750 to people have never been outside the 461 00:21:05,890 --> 00:21:02,360 city that is what the Milky Way will 462 00:21:07,750 --> 00:21:05,900 look like from the grounds if you don't 463 00:21:15,370 --> 00:21:07,760 have light pollution and if you have 464 00:21:16,840 --> 00:21:15,380 decent night vision oh okay and I heard 465 00:21:18,460 --> 00:21:16,850 an interesting anecdote a few years ago 466 00:21:20,620 --> 00:21:18,470 I don't know if it's true but it sounds 467 00:21:22,300 --> 00:21:20,630 like it could be true apparently many 468 00:21:25,180 --> 00:21:22,310 years ago there was a huge power outage 469 00:21:27,550 --> 00:21:25,190 in Southern California and then people 470 00:21:29,440 --> 00:21:27,560 saw this and they had no idea what was 471 00:21:34,020 --> 00:21:29,450 so they got scared and they called 472 00:21:38,710 --> 00:21:34,030 police there you go 473 00:21:41,620 --> 00:21:38,720 so here's two images of the Milky Way 474 00:21:42,690 --> 00:21:41,630 panoramic Li in optical and 475 00:21:45,670 --> 00:21:42,700 near-infrared 476 00:21:49,360 --> 00:21:45,680 photography I'll explain what so optical 477 00:21:51,550 --> 00:21:49,370 is the type of light that we can see we 478 00:21:55,060 --> 00:21:51,560 can see Li you know it goes from blue 479 00:21:58,990 --> 00:21:55,070 lights - and then you got green light 480 00:22:00,490 --> 00:21:59,000 orange or orange light and red lights 481 00:22:03,039 --> 00:22:00,500 with a bit more detail actually I 482 00:22:06,039 --> 00:22:03,049 skipped purple lights and this is near 483 00:22:08,620 --> 00:22:06,049 infrared lights and can somebody point 484 00:22:11,080 --> 00:22:08,630 out so you can all see that it's kind of 485 00:22:12,760 --> 00:22:11,090 the same but there's some differences 486 00:22:15,520 --> 00:22:12,770 could somebody point out a difference 487 00:22:17,620 --> 00:22:15,530 between the top image and the bottom 488 00:22:22,390 --> 00:22:17,630 image other than the kind of light 489 00:22:25,899 --> 00:22:22,400 they're in yes yeah so there's all these 490 00:22:28,120 --> 00:22:25,909 dust lanes in the top image it looks 491 00:22:30,010 --> 00:22:28,130 like it's black but it's not black 492 00:22:32,860 --> 00:22:30,020 there's a ton of stars there just a lot 493 00:22:36,010 --> 00:22:32,870 of the light is blocked out by 494 00:22:38,980 --> 00:22:36,020 intervening dust particles and dust it 495 00:22:42,220 --> 00:22:38,990 kind of affects all lights but it 496 00:22:44,649 --> 00:22:42,230 affects bluer lights a lot more than 497 00:22:46,899 --> 00:22:44,659 rhetoric or optical light a lot more 498 00:22:48,880 --> 00:22:46,909 than infrared light I learned something 499 00:22:51,340 --> 00:22:48,890 cool when I lived in Australia which is 500 00:22:53,320 --> 00:22:51,350 kind of after it was explained to me it 501 00:22:55,299 --> 00:22:53,330 was obvious so in the southern 502 00:22:57,159 --> 00:22:55,309 hemisphere this do see more of the Milky 503 00:22:59,830 --> 00:22:57,169 Way due to how things are oriented and 504 00:23:03,310 --> 00:22:59,840 for the Australian Aborigines their 505 00:23:06,750 --> 00:23:03,320 constellations weren't just you know 506 00:23:09,159 --> 00:23:06,760 connections of stars the dust lanes 507 00:23:11,020 --> 00:23:09,169 themselves could also be constellations 508 00:23:12,730 --> 00:23:11,030 it would make animals out of that and as 509 00:23:14,200 --> 00:23:12,740 it moved through season it would 510 00:23:21,730 --> 00:23:14,210 correspond to different parts of the 511 00:23:24,039 --> 00:23:21,740 fertility cycle so here's the Milky Way 512 00:23:27,039 --> 00:23:24,049 bulge or rather actions a whole galaxy 513 00:23:30,460 --> 00:23:27,049 including the Bulge as part of an 514 00:23:32,560 --> 00:23:30,470 artist's rendition and some of you may 515 00:23:34,720 --> 00:23:32,570 feel I'm being cheap right now I'm 516 00:23:37,240 --> 00:23:34,730 showing an artist's rendition of our own 517 00:23:39,370 --> 00:23:37,250 galaxy because someone tell me why I 518 00:23:47,740 --> 00:23:39,380 wouldn't be showing a photo of our 519 00:23:50,980 --> 00:23:47,750 galaxy yes in the back thank you that's 520 00:23:53,590 --> 00:23:50,990 exactly right yeah so the previous image 521 00:23:55,240 --> 00:23:53,600 is we're kind of like in the galaxy to 522 00:23:57,700 --> 00:23:55,250 see that right but really we're only 523 00:24:00,039 --> 00:23:57,710 seeing I don't know we're like 70 or 80 524 00:24:01,840 --> 00:24:00,049 percent outwards so in those image we're 525 00:24:04,419 --> 00:24:01,850 kind of seeing the inner 70% of the 526 00:24:06,190 --> 00:24:04,429 galaxy but here it's with somebody yeah 527 00:24:08,139 --> 00:24:06,200 if you've traveled like ten thousand 528 00:24:10,180 --> 00:24:08,149 light-years outwards and it's worse than 529 00:24:11,590 --> 00:24:10,190 that because if you did go out by ten or 530 00:24:13,210 --> 00:24:11,600 50,000 light years 531 00:24:16,600 --> 00:24:13,220 good luck sending this 532 00:24:17,260 --> 00:24:16,610 back you'd be like Oh how did I end up 533 00:24:22,510 --> 00:24:17,270 here 534 00:24:24,310 --> 00:24:22,520 or do I go you'd be screwed and so in 535 00:24:26,500 --> 00:24:24,320 this image of the galaxy the part that's 536 00:24:28,510 --> 00:24:26,510 rel so it's very idealized image the 537 00:24:32,500 --> 00:24:28,520 real galaxy is probably not super 538 00:24:34,299 --> 00:24:32,510 symmetric we kind of all galaxies many 539 00:24:37,000 --> 00:24:34,309 galaxies are symmetric but not perfectly 540 00:24:41,110 --> 00:24:37,010 so but Bryce Raman here the spiral arms 541 00:24:43,930 --> 00:24:41,120 are in blue and the Bulge or bar is in 542 00:24:46,690 --> 00:24:43,940 yellow the reason it's a different color 543 00:24:49,000 --> 00:24:46,700 is that there are fewer young stars in 544 00:24:51,940 --> 00:24:49,010 the Bulge and I'll explain I'll discuss 545 00:24:54,370 --> 00:24:51,950 that at the end so now we're going to 546 00:24:55,960 --> 00:24:54,380 see a video of a forming galaxies 547 00:24:57,220 --> 00:24:55,970 there's so many videos of galaxies 548 00:25:01,270 --> 00:24:57,230 forming out there I didn't know which 549 00:25:02,799 --> 00:25:01,280 ones to take but I took these two well 550 00:25:05,080 --> 00:25:02,809 okay look there's this one and another 551 00:25:08,620 --> 00:25:05,090 one afterwards we're gonna watch this go 552 00:25:10,690 --> 00:25:08,630 it shows Z or Z sorry on the top left 553 00:25:13,810 --> 00:25:10,700 that's the cosmological redshift that 554 00:25:16,120 --> 00:25:13,820 corresponds to time Zetas 15 means about 555 00:25:18,880 --> 00:25:16,130 13 and a half Giga years ago billion 556 00:25:19,990 --> 00:25:18,890 years ago sorry Zetas one means seven 557 00:25:23,440 --> 00:25:20,000 point eight billion years ago and the 558 00:25:25,690 --> 00:25:23,450 way galaxies form over there they're 559 00:25:27,580 --> 00:25:25,700 believed to have formed from tiny proto 560 00:25:29,470 --> 00:25:27,590 galaxies maybe a thousand or ten 561 00:25:32,140 --> 00:25:29,480 thousand times smaller and as the 562 00:25:34,480 --> 00:25:32,150 universe age they all come together and 563 00:25:38,049 --> 00:25:34,490 eventually we have a disk like we have 564 00:25:40,270 --> 00:25:38,059 now this picture is definitely accurate 565 00:25:43,029 --> 00:25:40,280 but the details might be off it's not 566 00:25:45,100 --> 00:25:43,039 it's a matter of controversy and so we 567 00:25:47,860 --> 00:25:45,110 see by this point most of the galaxies 568 00:25:49,630 --> 00:25:47,870 assembled there's kind of fewer big 569 00:25:54,039 --> 00:25:49,640 pieces coming in now there's still a lot 570 00:25:56,020 --> 00:25:54,049 of small pieces like for own galaxy but 571 00:26:00,279 --> 00:25:56,030 you know and the big things are there 572 00:26:01,899 --> 00:26:00,289 and does that thing have slowed down so 573 00:26:04,149 --> 00:26:01,909 it kind of looks like maybe the computer 574 00:26:07,000 --> 00:26:04,159 got slower cuz it's too complicated but 575 00:26:09,909 --> 00:26:07,010 that's not it it's just the ways that is 576 00:26:10,779 --> 00:26:09,919 defines as you go from Z to 15th is out 577 00:26:13,570 --> 00:26:10,789 of 5 578 00:26:15,220 --> 00:26:13,580 you only travel 1 billion years but as 579 00:26:17,230 --> 00:26:15,230 you go from 5 to 1 580 00:26:20,289 --> 00:26:17,240 you try let you go like 8 billion years 581 00:26:22,299 --> 00:26:20,299 it's kind of it's the mapping between 582 00:26:26,590 --> 00:26:22,309 the history of expansion of the universe 583 00:26:29,590 --> 00:26:26,600 and the actual age of things and now 584 00:26:31,720 --> 00:26:29,600 four is about when the Sun formed so 585 00:26:33,190 --> 00:26:31,730 this galaxy here would have a baby son 586 00:26:35,560 --> 00:26:33,200 if that was like the Milky Way we see 587 00:26:37,240 --> 00:26:35,570 that so reasonable spiral it's not 588 00:26:40,289 --> 00:26:37,250 completely symmetric but it's pretty 589 00:26:42,340 --> 00:26:40,299 close right like if this was a flower 590 00:26:44,590 --> 00:26:42,350 okay I mean it doesn't look like a 591 00:26:47,980 --> 00:26:44,600 flower but pretend it does it'd be kind 592 00:26:50,049 --> 00:26:47,990 of a pretty flower and unlike our galaxy 593 00:26:52,779 --> 00:26:50,059 this one has a pretty big merger going 594 00:26:55,390 --> 00:26:52,789 on at the end our galaxy now only has a 595 00:26:57,100 --> 00:26:55,400 has small mergers going on right now 596 00:26:59,740 --> 00:26:57,110 that's still ouch 597 00:27:02,590 --> 00:26:59,750 that's our galaxy into two billion years 598 00:27:04,779 --> 00:27:02,600 when it emerges from Andromeda and now 599 00:27:07,630 --> 00:27:04,789 here's a second galaxy and it already 600 00:27:09,549 --> 00:27:07,640 started it looks the same at first 601 00:27:15,940 --> 00:27:09,559 because they all wait you know I 602 00:27:22,000 --> 00:27:15,950 actually know sorry okay this is 603 00:27:25,630 --> 00:27:22,010 actually what I meant to look at okay 604 00:27:28,750 --> 00:27:25,640 this is just the this galaxy the point 605 00:27:31,029 --> 00:27:28,760 of it is that it's thought to be more 606 00:27:32,820 --> 00:27:31,039 similar to what the Milky Way might have 607 00:27:35,020 --> 00:27:32,830 gone through of course these are random 608 00:27:39,159 --> 00:27:35,030 realizations and go through the trillion 609 00:27:41,230 --> 00:27:39,169 times and never find a match but you'll 610 00:27:52,590 --> 00:27:41,240 get a qualitative match you know which 611 00:28:03,370 --> 00:27:57,430 so in this image the we see the light of 612 00:28:06,760 --> 00:28:03,380 gas and stars stars form from gas what 613 00:28:09,820 --> 00:28:06,770 we're not seeing is the lights from dust 614 00:28:11,860 --> 00:28:09,830 it's it's just turned off in this video 615 00:28:13,480 --> 00:28:11,870 the dust is still active and having 616 00:28:15,279 --> 00:28:13,490 physical effects but it's turned off 617 00:28:19,720 --> 00:28:15,289 because the video is meaning to 618 00:28:21,399 --> 00:28:19,730 emphasize the gas and the stars and what 619 00:28:24,039 --> 00:28:21,409 they bragged about when they made this 620 00:28:27,340 --> 00:28:24,049 is that they're able to make a pretty 621 00:28:29,380 --> 00:28:27,350 thin disc the people simulate these 622 00:28:31,390 --> 00:28:29,390 galaxies have been able to make disks of 623 00:28:34,029 --> 00:28:31,400 galaxies like the Milky Way hasn't shown 624 00:28:37,590 --> 00:28:34,039 you earlier for a long time but to make 625 00:28:39,700 --> 00:28:37,600 thin disks you know crêpes rather than 626 00:28:43,899 --> 00:28:39,710 pancakes from blue moon 627 00:28:46,330 --> 00:28:43,909 is a bit hard and galaxies are small are 628 00:28:49,240 --> 00:28:46,340 some more similar to crepes than to 629 00:28:52,240 --> 00:28:49,250 pancakes from Blue Moon all okay maybe 630 00:28:54,310 --> 00:28:52,250 not in this image but yeah this has a 631 00:28:56,500 --> 00:28:54,320 pretty thin bulge 632 00:29:03,130 --> 00:28:56,510 I ain't thin disc and you can see that 633 00:29:05,680 --> 00:29:03,140 there's a bulge already and so to go 634 00:29:08,260 --> 00:29:05,690 through why ball just matter really the 635 00:29:09,820 --> 00:29:08,270 whole galaxy matters you might come to 636 00:29:12,279 --> 00:29:09,830 another talking year from now they'll be 637 00:29:14,740 --> 00:29:12,289 talking about the disc or the outskirts 638 00:29:18,010 --> 00:29:14,750 or the star clusters every part of the 639 00:29:23,049 --> 00:29:18,020 galaxy matters the reason that the Bulge 640 00:29:25,720 --> 00:29:23,059 now and that the Balch matters is that 641 00:29:28,750 --> 00:29:25,730 it's many of the oldest stars in the 642 00:29:30,880 --> 00:29:28,760 galaxy that's why it's yellow and so by 643 00:29:33,850 --> 00:29:30,890 understanding that we can have a pretty 644 00:29:37,149 --> 00:29:33,860 good idea of how a disproportionate 645 00:29:38,529 --> 00:29:37,159 number of the first stars forms even 646 00:29:41,799 --> 00:29:38,539 though it's only a third of the total 647 00:29:44,889 --> 00:29:41,809 stars it might be like one half to two 648 00:29:47,380 --> 00:29:44,899 thirds of the oldest stars and I make a 649 00:29:49,570 --> 00:29:47,390 lot of analogies with history the field 650 00:29:52,360 --> 00:29:49,580 is now called galactic archaeology maybe 651 00:29:55,870 --> 00:29:52,370 for marketing reasons but imagine in 652 00:29:58,870 --> 00:29:55,880 history like you knew about you know the 653 00:30:01,330 --> 00:29:58,880 American Civil War and the Spanish 654 00:30:03,220 --> 00:30:01,340 Inquisition and that interesting stuff 655 00:30:05,289 --> 00:30:03,230 but you didn't know but the Sumerians 656 00:30:07,029 --> 00:30:05,299 and the Greeks your knowledge would be 657 00:30:08,799 --> 00:30:07,039 very incomplete you need to know that 658 00:30:13,180 --> 00:30:08,809 stuff is interesting as well and it 659 00:30:15,850 --> 00:30:13,190 helps complete the story all right 660 00:30:17,860 --> 00:30:15,860 so part one it's the shortest part it's 661 00:30:23,260 --> 00:30:17,870 the chemical characterization of ball 662 00:30:25,019 --> 00:30:23,270 stars it's it's short because located 663 00:30:28,750 --> 00:30:25,029 three parts in here there's chemistry 664 00:30:31,240 --> 00:30:28,760 there's structure and there's ages and 665 00:30:33,460 --> 00:30:31,250 chemistry might be the simplest in that 666 00:30:36,399 --> 00:30:33,470 it's reasonably solved I don't have as 667 00:30:39,669 --> 00:30:36,409 much controversy to share for you it 668 00:30:41,110 --> 00:30:39,679 wasn't solved maybe 30 years ago but 669 00:30:42,789 --> 00:30:41,120 it's solved now because we have these 670 00:30:45,370 --> 00:30:42,799 great new instruments we could look at 671 00:30:50,409 --> 00:30:45,380 hundreds of stars at a time this was 672 00:30:53,500 --> 00:30:50,419 taken by PhD thesis in Australia who 673 00:30:57,340 --> 00:30:53,510 knows what Fe might be 674 00:31:00,400 --> 00:30:57,350 that's right so the distribution and the 675 00:31:02,680 --> 00:31:00,410 metallicity of stars is usually it could 676 00:31:05,530 --> 00:31:02,690 be any metal you know why not copper or 677 00:31:07,299 --> 00:31:05,540 why not zinc iron is used because it 678 00:31:09,460 --> 00:31:07,309 happens to have a lot of atomic 679 00:31:12,100 --> 00:31:09,470 transitions and so you get a ton of 680 00:31:15,909 --> 00:31:12,110 lines when you look at the atmosphere of 681 00:31:18,520 --> 00:31:15,919 a star absorption lines that are due to 682 00:31:21,220 --> 00:31:18,530 iron and in fact if you go back a 683 00:31:23,070 --> 00:31:21,230 hundred years a lot of astronomers back 684 00:31:25,960 --> 00:31:23,080 then so they didn't have quantum physics 685 00:31:27,820 --> 00:31:25,970 understood but they knew that they 686 00:31:29,830 --> 00:31:27,830 didn't really know what's going on in 687 00:31:32,110 --> 00:31:29,840 the solar atmosphere they thought that 688 00:31:34,840 --> 00:31:32,120 the Sun was made of iron because iron 689 00:31:37,930 --> 00:31:34,850 makes a ton of absorption lines but 690 00:31:39,549 --> 00:31:37,940 that's not it it's just it just happens 691 00:31:42,760 --> 00:31:39,559 that at the typical temperature of a 692 00:31:44,650 --> 00:31:42,770 star a iron has a lot of transitions and 693 00:31:46,930 --> 00:31:44,660 so we use iron to measure things all 694 00:31:51,330 --> 00:31:46,940 right so here it's a logarithmic ratio 695 00:31:53,950 --> 00:31:51,340 of iron to hydrogen minus 1 means 696 00:31:58,240 --> 00:31:53,960 one-tenth the iron to hydrogen ratio of 697 00:32:00,070 --> 00:31:58,250 the Sun and plus 0.4 means about four 698 00:32:02,409 --> 00:32:00,080 times the iron to hydrogen ratio of the 699 00:32:05,200 --> 00:32:02,419 start of the Sun and it turns out that 700 00:32:09,610 --> 00:32:05,210 almost all bulb stars are in that range 701 00:32:12,340 --> 00:32:09,620 and a typical value is zero I always 702 00:32:14,919 --> 00:32:12,350 think that this is a big coincidence but 703 00:32:18,490 --> 00:32:14,929 the iron the metallicity of the Sun is 704 00:32:20,200 --> 00:32:18,500 very typical of the metallicity of most 705 00:32:21,820 --> 00:32:20,210 of the stars in the Balch and indeed 706 00:32:23,950 --> 00:32:21,830 elsewhere in the galaxy it's a little 707 00:32:26,620 --> 00:32:23,960 higher but I don't know I think it's 708 00:32:29,620 --> 00:32:26,630 cool that the Sun is such an all right 709 00:32:31,390 --> 00:32:29,630 an average star in metallicity where 710 00:32:33,970 --> 00:32:31,400 metallicity and chemistry is a thing 711 00:32:39,039 --> 00:32:33,980 that marries the most between different 712 00:32:41,740 --> 00:32:39,049 stars and we can also study other 713 00:32:43,990 --> 00:32:41,750 elements I could go on and on with other 714 00:32:45,700 --> 00:32:44,000 elements but it'd be like too much 715 00:32:49,120 --> 00:32:45,710 information and to be honest the other 716 00:32:53,799 --> 00:32:49,130 elements aren't measured as well so it's 717 00:32:57,250 --> 00:32:53,809 not as informative but here we show OSI 718 00:33:00,430 --> 00:32:57,260 and SIA and see CA calcium so oxygen 719 00:33:02,740 --> 00:33:00,440 silicon and calcium and it's the ratio 720 00:33:05,890 --> 00:33:02,750 relative to iron and what's been 721 00:33:06,940 --> 00:33:05,900 confirmed over most decades of research 722 00:33:09,669 --> 00:33:06,950 the past 20 or 3 723 00:33:13,990 --> 00:33:09,679 years is that the ratios are higher 724 00:33:17,470 --> 00:33:14,000 involved stars than in the Sun so this 725 00:33:20,350 --> 00:33:17,480 is one place in which one area in which 726 00:33:23,019 --> 00:33:20,360 both stars are different they just have 727 00:33:24,759 --> 00:33:23,029 more relative abundances of these 728 00:33:27,610 --> 00:33:24,769 elements and that's kind of cool imagine 729 00:33:30,490 --> 00:33:27,620 you form an earth there right and earth 730 00:33:32,980 --> 00:33:30,500 is I think iron is the second most 731 00:33:34,930 --> 00:33:32,990 abundant element after oxygen and the 732 00:33:35,889 --> 00:33:34,940 earth and so imagine you truncated that 733 00:33:38,799 --> 00:33:35,899 in half it might have a different 734 00:33:40,930 --> 00:33:38,809 evolution of life going on and the 735 00:33:43,600 --> 00:33:40,940 reason for this is thought to be that 736 00:33:45,610 --> 00:33:43,610 the balls formed quickly that's why it 737 00:33:49,990 --> 00:33:45,620 was yellow in the previous images the 738 00:33:51,960 --> 00:33:50,000 stars are older and therefore it says 739 00:33:54,370 --> 00:33:51,970 more of those kinds of supernovae 740 00:33:55,980 --> 00:33:54,380 alright I'll skip this law structure of 741 00:34:00,750 --> 00:33:55,990 the Bulge 742 00:34:06,779 --> 00:34:04,060 alright so this is the Hubble tuning 743 00:34:10,270 --> 00:34:06,789 fork diagram and it kind of shows that 744 00:34:12,569 --> 00:34:10,280 galaxies come in a huge variety of 745 00:34:14,889 --> 00:34:12,579 shapes and sizes it was first under 746 00:34:17,800 --> 00:34:14,899 written down by Edwin Hubble 747 00:34:19,599 --> 00:34:17,810 approximately 100 years ago and he had 748 00:34:22,419 --> 00:34:19,609 some story about it about why this 749 00:34:23,859 --> 00:34:22,429 happens it doesn't hold up that's fine 750 00:34:25,240 --> 00:34:23,869 he didn't guess the reason but what's 751 00:34:28,510 --> 00:34:25,250 interesting is that we still don't know 752 00:34:31,210 --> 00:34:28,520 the reason well we know a little bit but 753 00:34:34,270 --> 00:34:31,220 not really fully why galaxies come in 754 00:34:38,050 --> 00:34:34,280 these shapes and when astronomers 755 00:34:40,659 --> 00:34:38,060 realized that there were galaxies there 756 00:34:43,260 --> 00:34:40,669 they didn't realize what kind of galaxy 757 00:34:47,649 --> 00:34:43,270 the Milky Way was is it one like this 758 00:34:50,710 --> 00:34:47,659 like this like this like this of course 759 00:34:53,079 --> 00:34:50,720 you guys might guess because I showed 760 00:34:56,319 --> 00:34:53,089 you an image earlier of an artist's 761 00:34:59,079 --> 00:34:56,329 rendition does anyone want to point to 762 00:35:01,510 --> 00:34:59,089 one of these or I don't know if it's big 763 00:35:03,460 --> 00:35:01,520 enough for everybody see and you say 764 00:35:09,849 --> 00:35:03,470 which one is most similar to the Milky 765 00:35:13,569 --> 00:35:09,859 Way yes who said that yeah down there 766 00:35:16,450 --> 00:35:13,579 probably this one maybe this one so the 767 00:35:20,000 --> 00:35:16,460 bar as I'll explain soon as reasonably 768 00:35:23,690 --> 00:35:20,010 well understood however the spiral arms 769 00:35:26,420 --> 00:35:23,700 are not that well understood and maybe I 770 00:35:28,700 --> 00:35:26,430 will show you great images of the bar 771 00:35:30,140 --> 00:35:28,710 shortly of what it could look like it's 772 00:35:32,210 --> 00:35:30,150 one of the achievement not really my 773 00:35:33,710 --> 00:35:32,220 main five minutes one of the 774 00:35:36,410 --> 00:35:33,720 achievements of astronomy in the past 775 00:35:37,390 --> 00:35:36,420 ten years but there's spiral arms not 776 00:35:41,270 --> 00:35:37,400 yet solved 777 00:35:43,970 --> 00:35:41,280 alright so the Milky Way is not an 778 00:35:48,380 --> 00:35:43,980 unbarred galaxy like the Whirlpool 779 00:35:50,480 --> 00:35:48,390 Galaxy this is an image of a typical 780 00:35:52,820 --> 00:35:50,490 unbarred galaxy it might have a very 781 00:35:55,670 --> 00:35:52,830 very weak bar in here that's possible 782 00:35:57,260 --> 00:35:55,680 but it'll be very weak so whatever if 783 00:35:59,120 --> 00:35:57,270 somebody tell me something else about 784 00:36:05,570 --> 00:35:59,130 the Whirlpool Galaxy that's different 785 00:36:07,670 --> 00:36:05,580 from the Milky Way yes as a companion 786 00:36:09,410 --> 00:36:07,680 right here the Milky Way does have 787 00:36:14,060 --> 00:36:09,420 companions but nothing that's like a 788 00:36:18,250 --> 00:36:14,070 quarter of the size like that the Milky 789 00:36:21,770 --> 00:36:18,260 Way is a barred spiral galaxy like NGC 790 00:36:24,380 --> 00:36:21,780 1559 maybe not quite exactly like this 791 00:36:26,030 --> 00:36:24,390 this is a very strong bar we see there's 792 00:36:29,060 --> 00:36:26,040 a lot of dust lanes just like in our 793 00:36:30,410 --> 00:36:29,070 galaxy and if I could ask another 794 00:36:34,640 --> 00:36:30,420 question for you guys though the 795 00:36:36,200 --> 00:36:34,650 question is on the screen why is it that 796 00:36:39,770 --> 00:36:36,210 this galaxy the one that showed you 797 00:36:43,250 --> 00:36:39,780 before circles but this one here appears 798 00:36:45,830 --> 00:36:43,260 to be longer in one axis and the other 799 00:36:47,390 --> 00:36:45,840 axis it's like twice the length does 800 00:36:54,650 --> 00:36:47,400 anyone have a good guess as to why that 801 00:36:57,350 --> 00:36:54,660 might be yes that's right 802 00:36:59,450 --> 00:36:57,360 of course it could actually be that it 803 00:37:01,580 --> 00:36:59,460 is slightly asymmetric that does happen 804 00:37:04,100 --> 00:37:01,590 there could be a companion just off 805 00:37:06,080 --> 00:37:04,110 that's torquing it but the most likely 806 00:37:10,040 --> 00:37:06,090 explanation you take something that's 807 00:37:14,210 --> 00:37:10,050 flat you tilt it and then it will appear 808 00:37:16,850 --> 00:37:14,220 longer in one axis then the other the 809 00:37:19,100 --> 00:37:16,860 Milky Way is the only galaxy that we can 810 00:37:21,350 --> 00:37:19,110 study in three dimensions all other 811 00:37:25,880 --> 00:37:21,360 galaxies appears two-dimensional 812 00:37:28,070 --> 00:37:25,890 projections and another image this one 813 00:37:32,330 --> 00:37:28,080 is more plausible the Milky Way is a 814 00:37:33,880 --> 00:37:32,340 barred spiral galaxy like NGC 43 94 this 815 00:37:35,650 --> 00:37:33,890 one's 54 million light years 816 00:37:38,230 --> 00:37:35,660 away in the constellation Coma Berenices 817 00:37:41,170 --> 00:37:38,240 no one's gonna remember that that's okay 818 00:37:44,560 --> 00:37:41,180 what's cool about this one this is such 819 00:37:47,710 --> 00:37:44,570 a strong bar this is like really strong 820 00:37:50,290 --> 00:37:47,720 and it's actually kind of similar to the 821 00:37:51,940 --> 00:37:50,300 Milky Way's bar yeah we're gonna see in 822 00:37:58,630 --> 00:37:51,950 a few screens somebody said something 823 00:38:01,690 --> 00:37:58,640 yes oh sorry okay so let's go back here 824 00:38:03,190 --> 00:38:01,700 so bulge is like the central part if you 825 00:38:05,500 --> 00:38:03,200 think of a disk of the galaxy as a 826 00:38:07,030 --> 00:38:05,510 pancake in the middle of the pancake you 827 00:38:16,900 --> 00:38:07,040 can have like a pile of whipped cream or 828 00:38:19,930 --> 00:38:16,910 butter or I don't know spinach so that 829 00:38:22,450 --> 00:38:19,940 can take on different shapes apparent 830 00:38:23,950 --> 00:38:22,460 shapes depending on the dynamics and the 831 00:38:26,950 --> 00:38:23,960 gravity and the interactions of 832 00:38:28,900 --> 00:38:26,960 neighboring galaxies and sometimes it's 833 00:38:33,300 --> 00:38:28,910 just a big blob in the middle like in 834 00:38:36,630 --> 00:38:33,310 these or in fact like right here and 835 00:38:41,740 --> 00:38:36,640 sometimes you end up with a barred shape 836 00:38:43,180 --> 00:38:41,750 like this in different contexts and it 837 00:38:45,670 --> 00:38:43,190 really depends on the history of the 838 00:38:49,240 --> 00:38:45,680 interaction so I'll get to that soon but 839 00:38:53,110 --> 00:38:49,250 thank you for asking that all right 840 00:38:55,240 --> 00:38:53,120 where we were on this one and okay so we 841 00:38:57,970 --> 00:38:55,250 didn't we didn't always know if the 842 00:39:03,550 --> 00:38:57,980 Milky Way's Bulge was a Bart shaped like 843 00:39:07,930 --> 00:39:03,560 a bar like this right or if it was 844 00:39:10,540 --> 00:39:07,940 shaped as a spheroid like this it's hard 845 00:39:12,700 --> 00:39:10,550 to guess and you go back thirty years 846 00:39:15,430 --> 00:39:12,710 and everything was less precise and it 847 00:39:20,050 --> 00:39:15,440 was less data the first really good 848 00:39:21,730 --> 00:39:20,060 evidence came from Stan akin all 1994 849 00:39:24,310 --> 00:39:21,740 Chris Stanek then he was a graduate 850 00:39:26,920 --> 00:39:24,320 student at Princeton and imagine that 851 00:39:29,410 --> 00:39:26,930 we're in this artist rendition if you 852 00:39:32,020 --> 00:39:29,420 look at the stars here and then you look 853 00:39:34,540 --> 00:39:32,030 at the stars here the ones that are here 854 00:39:37,330 --> 00:39:34,550 because they're closer are going to be 855 00:39:40,390 --> 00:39:37,340 brighter let's say they're like thirty 856 00:39:42,100 --> 00:39:40,400 percent after twenty percent closer then 857 00:39:46,300 --> 00:39:42,110 there'll be about forty percent brighter 858 00:39:47,000 --> 00:39:46,310 and that's what he found when he looked 859 00:39:59,480 --> 00:39:47,010 at 860 00:40:04,130 --> 00:39:59,490 stars are slightly brighter over here 861 00:40:06,050 --> 00:40:04,140 than over here and from that he infer he 862 00:40:08,960 --> 00:40:06,060 called it evidence for the Galactic Bar 863 00:40:11,420 --> 00:40:08,970 this was done of Polish astronomers here 864 00:40:13,400 --> 00:40:11,430 I show a photo of him it's an 865 00:40:15,080 --> 00:40:13,410 interesting anecdote about the referee 866 00:40:16,880 --> 00:40:15,090 process in science this was somewhat 867 00:40:19,070 --> 00:40:16,890 controversial people thought the Milky 868 00:40:22,220 --> 00:40:19,080 Way had more of a balls like this a 869 00:40:24,590 --> 00:40:22,230 spheroid and I think the first referee 870 00:40:27,470 --> 00:40:24,600 either challenged it or rejected the 871 00:40:29,570 --> 00:40:27,480 paper he said you cannot submit a paper 872 00:40:35,290 --> 00:40:29,580 on the evidence for the Galactic Bar 873 00:40:38,300 --> 00:40:35,300 because there is no Galactic bar so ok 874 00:40:39,740 --> 00:40:38,310 the process of peer review which we hear 875 00:40:42,800 --> 00:40:39,750 about in the media in the newspaper 876 00:40:46,040 --> 00:40:42,810 sometimes is making science sacred it's 877 00:40:48,830 --> 00:40:46,050 really good it does help things but it's 878 00:40:51,950 --> 00:40:48,840 not perfect something that helps in 879 00:40:55,040 --> 00:40:51,960 general will have instances where it 880 00:40:57,980 --> 00:40:55,050 either helps something bad or blocks 881 00:41:00,020 --> 00:40:57,990 something good though in this case they 882 00:41:02,840 --> 00:41:00,030 were able to get to another referee and 883 00:41:04,430 --> 00:41:02,850 that's fine you do get second chances 884 00:41:07,820 --> 00:41:04,440 because it's realized that this can 885 00:41:11,210 --> 00:41:07,830 happen but you know that was kind of a 886 00:41:13,040 --> 00:41:11,220 course image that static God right he 887 00:41:14,750 --> 00:41:13,050 said evidence for the Galactic Bar 888 00:41:17,270 --> 00:41:14,760 that's great but if we want to know what 889 00:41:19,220 --> 00:41:17,280 the Milky Way looks like right we need a 890 00:41:21,200 --> 00:41:19,230 lot more than evidence right I mean both 891 00:41:24,500 --> 00:41:21,210 of these have evidence they're different 892 00:41:27,470 --> 00:41:24,510 which one's the accurate representation 893 00:41:29,510 --> 00:41:27,480 we'd like to know and one thing that's 894 00:41:32,840 --> 00:41:29,520 helped is the improvements in CCD 895 00:41:35,120 --> 00:41:32,850 technology I remember when digital 896 00:41:37,190 --> 00:41:35,130 cameras first went on sale or maybe when 897 00:41:40,760 --> 00:41:37,200 ii went on sale at prime that's at first 898 00:41:42,620 --> 00:41:40,770 you had like 3 or 4 megapixels and that 899 00:41:47,630 --> 00:41:42,630 was good and it was like five hundred 900 00:41:49,370 --> 00:41:47,640 dollars no now you could get i don't 901 00:41:51,920 --> 00:41:49,380 even know what it's up to now maybe like 902 00:41:55,280 --> 00:41:51,930 20 megapixels for $200 or something it's 903 00:41:57,970 --> 00:41:55,290 just improved very rapidly and the same 904 00:41:59,480 --> 00:41:57,980 thing is true of astronomy observatories 905 00:42:07,040 --> 00:41:59,490 the 906 00:42:09,800 --> 00:42:07,050 Stanek used was five megapixels it was 907 00:42:13,160 --> 00:42:09,810 from me the Warsaw observatory located 908 00:42:14,420 --> 00:42:13,170 in Chile in South America a few hours 909 00:42:16,910 --> 00:42:14,430 north of Santiago 910 00:42:18,170 --> 00:42:16,920 now we regularly use cameras and 911 00:42:22,520 --> 00:42:18,180 astronomy that are a few hundred 912 00:42:26,810 --> 00:42:22,530 megapixels this is a CCD charge-coupled 913 00:42:30,140 --> 00:42:26,820 device a single one of these has more 914 00:42:31,760 --> 00:42:30,150 pixels on it actually this is the CCD 915 00:42:33,350 --> 00:42:31,770 charge-coupled device you see there's 916 00:42:34,790 --> 00:42:33,360 many of them together it's hollow many 917 00:42:37,010 --> 00:42:34,800 of them together because it's easier to 918 00:42:40,250 --> 00:42:37,020 do it that way than to make one big one 919 00:42:43,100 --> 00:42:40,260 and a single one of these has more 920 00:42:44,840 --> 00:42:43,110 pixels on it than the camera that was 921 00:42:46,640 --> 00:42:44,850 used to confirm the existence to the bar 922 00:42:49,040 --> 00:42:46,650 in the 1990s it's really improved 923 00:42:51,530 --> 00:42:49,050 rapidly and here we have an image of the 924 00:42:53,600 --> 00:42:51,540 sky here it's great and then there's 925 00:42:57,590 --> 00:42:53,610 another coincidence that as much as 926 00:43:01,040 --> 00:42:57,600 cameras have gotten bigger right at 927 00:43:03,130 --> 00:43:01,050 about the same speed hard drives have 928 00:43:06,080 --> 00:43:03,140 gone in bigger as well right I remember 929 00:43:07,990 --> 00:43:06,090 playing computer games and their 90s if 930 00:43:10,400 --> 00:43:08,000 you wanted to play one game 931 00:43:14,120 --> 00:43:10,410 you'd have to delete the other game 932 00:43:16,700 --> 00:43:14,130 first hard drives are really small and I 933 00:43:23,090 --> 00:43:16,710 think the teenagers here have any of you 934 00:43:25,700 --> 00:43:23,100 ever done that Wow okay well I had to do 935 00:43:26,560 --> 00:43:25,710 that all the time and you know climbing 936 00:43:29,660 --> 00:43:26,570 back here 937 00:43:32,720 --> 00:43:29,670 imagine CCDs had grown much much faster 938 00:43:34,099 --> 00:43:32,730 than hard drives that would totally suck 939 00:43:36,170 --> 00:43:34,109 for astronomy because we would take 940 00:43:38,270 --> 00:43:36,180 these great pictures and we wouldn't be 941 00:43:41,270 --> 00:43:38,280 able to store it ok so there's like 100 942 00:43:44,450 --> 00:43:41,280 times more data now and people have used 943 00:43:48,760 --> 00:43:44,460 it properly and this is from Christopher 944 00:43:54,349 --> 00:43:48,770 Wegg who did a postdoc in Germany and 945 00:43:56,240 --> 00:43:54,359 but grew up in the UK and it's a deep 946 00:43:58,670 --> 00:43:56,250 rejected model so same methodology of 947 00:44:01,210 --> 00:43:58,680 static slightly more sophisticated but 948 00:44:04,160 --> 00:44:01,220 just hundreds of times more data and 949 00:44:05,840 --> 00:44:04,170 this is a deep rejected model this is 950 00:44:09,200 --> 00:44:05,850 what the Milky Way's bar would look like 951 00:44:11,780 --> 00:44:09,210 face on this is what it look like slide 952 00:44:12,890 --> 00:44:11,790 on and this is kind of what it looks 953 00:44:18,230 --> 00:44:12,900 like 954 00:44:21,019 --> 00:44:18,240 from the Sun what happens is here okay 955 00:44:23,150 --> 00:44:21,029 so if the Sun is here we see this and 956 00:44:25,970 --> 00:44:23,160 then like this side here is taller than 957 00:44:28,339 --> 00:44:25,980 that side because it's closer but this 958 00:44:30,170 --> 00:44:28,349 here the second image is what you would 959 00:44:31,849 --> 00:44:30,180 see if you were living right here if the 960 00:44:33,529 --> 00:44:31,859 Sun was there it see both sides 961 00:44:36,140 --> 00:44:33,539 symmetrically and it kind of has like an 962 00:44:39,680 --> 00:44:36,150 X shape or a peanut shape it's a really 963 00:44:42,890 --> 00:44:39,690 remarkable image in 20 years we've gone 964 00:44:45,559 --> 00:44:42,900 from rejecting papers that said that the 965 00:44:49,130 --> 00:44:45,569 galaxy might have a bar to having a 966 00:44:51,289 --> 00:44:49,140 really precisely projection of what the 967 00:44:53,870 --> 00:44:51,299 bar looks like I think that's a great 968 00:44:55,999 --> 00:44:53,880 achievement and then you might be say 969 00:44:57,799 --> 00:44:56,009 okay that's from a model there's a lot 970 00:44:59,420 --> 00:44:57,809 of analysis going on 971 00:45:01,099 --> 00:44:59,430 I don't trust it's too complicated 972 00:45:04,370 --> 00:45:01,109 computer models will give you whatever 973 00:45:06,170 --> 00:45:04,380 you want okay well sometimes true in 974 00:45:09,440 --> 00:45:06,180 this case I don't agree because I know 975 00:45:13,660 --> 00:45:09,450 what went into the model but here is an 976 00:45:16,039 --> 00:45:13,670 image not taken in the near-infrared 977 00:45:20,059 --> 00:45:16,049 data like this but from mid-infrared 978 00:45:22,759 --> 00:45:20,069 data like that so maybe 5,000 nanometers 979 00:45:24,559 --> 00:45:22,769 or light that's about eight times longer 980 00:45:27,559 --> 00:45:24,569 than the reddest lights that we can see 981 00:45:30,769 --> 00:45:27,569 and at those wavelengths thus there's 982 00:45:34,940 --> 00:45:30,779 almost nothing and young stars don't 983 00:45:38,630 --> 00:45:34,950 contribute much so we only see sorry we 984 00:45:41,599 --> 00:45:38,640 only see old red stars and if you look 985 00:45:45,519 --> 00:45:41,609 at in those image the Milky Way has an X 986 00:45:47,960 --> 00:45:45,529 shape in its bar when if you slide on 987 00:45:49,160 --> 00:45:47,970 which is very very prominent I don't 988 00:45:50,390 --> 00:45:49,170 know if you guys could see it because 989 00:45:52,299 --> 00:45:50,400 there's a lot of light in this room can 990 00:45:54,559 --> 00:45:52,309 you guys see that there's an X in here 991 00:45:59,120 --> 00:45:54,569 okay great 992 00:46:02,749 --> 00:45:59,130 oh okay actually there's this better 993 00:46:05,059 --> 00:46:02,759 image here and you see like the disc 994 00:46:07,700 --> 00:46:05,069 right I said it was thin earlier look at 995 00:46:10,519 --> 00:46:07,710 how thin that is relative to its length 996 00:46:18,380 --> 00:46:10,529 right it's like 50 times longer than its 997 00:46:20,239 --> 00:46:18,390 tall that is a type of a class of orbits 998 00:46:21,920 --> 00:46:20,249 happening so the X you might think it's 999 00:46:24,049 --> 00:46:21,930 one thing it's actually two things I'm 1000 00:46:26,390 --> 00:46:24,059 gonna try and hold my hand really steady 1001 00:46:29,720 --> 00:46:26,400 over here to get this right you've got 1002 00:46:31,549 --> 00:46:29,730 some orbits that are like this right and 1003 00:46:34,460 --> 00:46:31,559 then you've got some other orbits that 1004 00:46:35,900 --> 00:46:34,470 are like this and they're even there's 1005 00:46:37,640 --> 00:46:35,910 an even number of them because the 1006 00:46:39,769 --> 00:46:37,650 galaxy is symmetric between the north 1007 00:46:45,529 --> 00:46:39,779 and south and when you view them 1008 00:46:48,799 --> 00:46:45,539 together you end up with an X in 1009 00:46:51,589 --> 00:46:48,809 combination and now that's an 1010 00:46:52,010 --> 00:46:51,599 explanation but why do we care I'll 1011 00:46:54,700 --> 00:46:52,020 answer 1012 00:47:02,829 --> 00:46:54,710 oh sorry do you want to ask something 1013 00:47:16,069 --> 00:47:13,190 that is I think so that's a very good 1014 00:47:18,079 --> 00:47:16,079 question actually I think it kind of 1015 00:47:21,769 --> 00:47:18,089 looks like a funnel but like a weak one 1016 00:47:26,299 --> 00:47:21,779 in the middle of it and then as you move 1017 00:47:29,329 --> 00:47:26,309 to the side there isn't going on here 1018 00:47:31,490 --> 00:47:29,339 it's okay sorry I'm not sure actually 1019 00:47:40,039 --> 00:47:31,500 but that's that's actually a very good 1020 00:47:41,750 --> 00:47:40,049 question yes they come in a variety 1021 00:47:44,180 --> 00:47:41,760 there actually so some of them are 1022 00:47:46,789 --> 00:47:44,190 circular or elliptical Ammar completely 1023 00:47:49,309 --> 00:47:46,799 chaotic I I don't have pictures of balls 1024 00:47:50,960 --> 00:47:49,319 orbits in here why are give an 1025 00:47:53,870 --> 00:47:50,970 explanation of why orbits are 1026 00:47:56,750 --> 00:47:53,880 complicated in the solar system orbits 1027 00:47:59,660 --> 00:47:56,760 are circle circle sorry they're circles 1028 00:48:01,609 --> 00:47:59,670 or ellipses and the reason that 1029 00:48:03,829 --> 00:48:01,619 simplicity happens is that no matter 1030 00:48:08,059 --> 00:48:03,839 where you are in the solar system all of 1031 00:48:10,190 --> 00:48:08,069 the mass is within you because 99.9% of 1032 00:48:12,289 --> 00:48:10,200 the mass is due to the Sun but in a 1033 00:48:14,859 --> 00:48:12,299 galaxy let's say you start off on an 1034 00:48:17,329 --> 00:48:14,869 eccentric orbit as you move outwards 1035 00:48:19,010 --> 00:48:17,339 then there's more mass within you 1036 00:48:21,799 --> 00:48:19,020 there's no point mass at the center it's 1037 00:48:23,420 --> 00:48:21,809 a distribution of mass and that causes 1038 00:48:29,240 --> 00:48:23,430 the orbits to take on really weird 1039 00:48:31,640 --> 00:48:29,250 shapes really good question - so I 1040 00:48:33,589 --> 00:48:31,650 notice why do we care that there's an X 1041 00:48:37,460 --> 00:48:33,599 I show three different things here this 1042 00:48:39,500 --> 00:48:37,470 is NGC 4710 another similar galaxy with 1043 00:48:41,600 --> 00:48:39,510 a very strong X 1044 00:48:43,460 --> 00:48:41,610 this is the D projection shown below and 1045 00:48:46,130 --> 00:48:43,470 this is an n body simulation with like 1046 00:48:50,050 --> 00:48:46,140 500,000 particles that evolve and we see 1047 00:48:52,780 --> 00:48:50,060 that an X emerges in the bar over time 1048 00:48:56,060 --> 00:48:52,790 so bars are kind of generic in 1049 00:48:58,460 --> 00:48:56,070 simulations of galaxy formation pretty 1050 00:49:02,300 --> 00:48:58,470 much anything can form a bar but 1051 00:49:05,660 --> 00:49:02,310 typically to have a very strong X not 1052 00:49:10,130 --> 00:49:05,670 always but usually you need to have a 1053 00:49:12,290 --> 00:49:10,140 very quiet galaxy if you have a merger 1054 00:49:15,860 --> 00:49:12,300 it'll jumble up the orbits and you'll 1055 00:49:18,350 --> 00:49:15,870 get a spheroid usually and so for the X 1056 00:49:20,930 --> 00:49:18,360 in the Milky Way to be so strong that 1057 00:49:22,790 --> 00:49:20,940 means that there probably hasn't been a 1058 00:49:26,930 --> 00:49:22,800 major merger in a long time do you have 1059 00:49:30,020 --> 00:49:26,940 your hand up okay all right so that's 1060 00:49:32,630 --> 00:49:30,030 the global picture of the bar it solved 1061 00:49:35,210 --> 00:49:32,640 that I think that's really cool what's 1062 00:49:37,430 --> 00:49:35,220 not solved well the detailed picture is 1063 00:49:40,190 --> 00:49:37,440 not solved if you look at all the stars 1064 00:49:42,290 --> 00:49:40,200 together there's an X but if you break 1065 00:49:46,370 --> 00:49:42,300 up the Stars into different ethnicities 1066 00:49:49,520 --> 00:49:46,380 let's say they're really so at the 1067 00:49:51,590 --> 00:49:49,530 metal-rich stars that yeah it's pretty 1068 00:49:54,170 --> 00:49:51,600 prominent this is an analysis done by 1069 00:49:56,120 --> 00:49:54,180 Matt apartheid he was a graduate student 1070 00:49:58,340 --> 00:49:56,130 in Germany where the brilliant thesis 1071 00:50:00,140 --> 00:49:58,350 but for more metal-poor stars the ones 1072 00:50:01,850 --> 00:50:00,150 that are more metal form in a Sun it's 1073 00:50:05,180 --> 00:50:01,860 much weaker it's still there but it's 1074 00:50:09,200 --> 00:50:05,190 far weaker and you might wonder why that 1075 00:50:10,250 --> 00:50:09,210 is and the answer is don't know that's 1076 00:50:15,440 --> 00:50:10,260 the next step 1077 00:50:17,380 --> 00:50:15,450 in bolts research ok part 3 the ages of 1078 00:50:20,090 --> 00:50:17,390 all stars 1079 00:50:23,060 --> 00:50:20,100 so galactic archaeology and the 1080 00:50:25,160 --> 00:50:23,070 challenge of age dating I used that term 1081 00:50:27,500 --> 00:50:25,170 before so historical archaeology has 1082 00:50:30,440 --> 00:50:27,510 been revolutionized by carbon dating 1083 00:50:32,240 --> 00:50:30,450 methods no such luck for galactic 1084 00:50:34,910 --> 00:50:32,250 archaeology we're not successful at 1085 00:50:36,470 --> 00:50:34,920 least so far when we estimate the ages 1086 00:50:39,260 --> 00:50:36,480 of stars to try and figure out which 1087 00:50:42,350 --> 00:50:39,270 group of stars came first for usually 1088 00:50:45,680 --> 00:50:42,360 off by like 10 or 15% unfortunately and 1089 00:50:48,980 --> 00:50:45,690 that and often more actually I think 10% 1090 00:50:51,440 --> 00:50:48,990 is an optimistic estimate of the error 1091 00:50:53,230 --> 00:50:51,450 in estimating the ages of stars because 1092 00:50:55,900 --> 00:50:53,240 there's no equivalent to carbon dating 1093 00:50:57,520 --> 00:50:55,910 that could give you a 1% age and you 1094 00:50:59,859 --> 00:50:57,530 might imagine that we'd have more 1095 00:51:02,770 --> 00:50:59,869 uncertainty in our books on the history 1096 00:51:05,200 --> 00:51:02,780 of civilization if we didn't know who 1097 00:51:07,060 --> 00:51:05,210 came first we might be able to 1098 00:51:10,900 --> 00:51:07,070 reconstruct it from improvements in 1099 00:51:15,010 --> 00:51:10,910 pottery or written history when we have 1100 00:51:17,020 --> 00:51:15,020 it but sometimes it wouldn't be all 1101 00:51:20,710 --> 00:51:17,030 right so the first evidence that the 1102 00:51:24,790 --> 00:51:20,720 Stars and the balls were older came from 1103 00:51:26,440 --> 00:51:24,800 Nassau and Blanco they looked at red 1104 00:51:28,300 --> 00:51:26,450 variables towards the center of the 1105 00:51:31,620 --> 00:51:28,310 Milky Way and they found that those 1106 00:51:34,600 --> 00:51:31,630 variables had shorter periods of 1107 00:51:37,359 --> 00:51:34,610 oscillation so typically they or they 1108 00:51:40,120 --> 00:51:37,369 they so these are variables they get 1109 00:51:42,010 --> 00:51:40,130 bigger bigger bigger smaller smaller 1110 00:51:44,140 --> 00:51:42,020 smaller bigger bigger bigger smaller 1111 00:51:45,430 --> 00:51:44,150 smaller smaller big differences in 1112 00:51:47,830 --> 00:51:45,440 variations it could be two or three 1113 00:51:50,530 --> 00:51:47,840 times brighter at the end the periods 1114 00:51:52,060 --> 00:51:50,540 were like a couple hundred days and in 1115 00:51:54,160 --> 00:51:52,070 the solar neighborhood we get such 1116 00:51:57,520 --> 00:51:54,170 within like a thousand light years at a 1117 00:51:59,590 --> 00:51:57,530 Sun we get such variables but we also 1118 00:52:03,970 --> 00:51:59,600 get variables that take thousands of 1119 00:52:06,400 --> 00:52:03,980 days to oscillate and so they observed 1120 00:52:09,550 --> 00:52:06,410 that difference and they didn't and they 1121 00:52:13,109 --> 00:52:09,560 actually did not know that this was due 1122 00:52:15,010 --> 00:52:13,119 to an age effect but it's the first 1123 00:52:17,349 --> 00:52:15,020 within the literature it's when the 1124 00:52:19,300 --> 00:52:17,359 first statements that's explicitly 1125 00:52:20,980 --> 00:52:19,310 written down which now with what we know 1126 00:52:23,349 --> 00:52:20,990 now about astronomy and how in variable 1127 00:52:26,260 --> 00:52:23,359 stars can be interpreted as new to an 1128 00:52:28,480 --> 00:52:26,270 age difference a distribution and a 1129 00:52:31,720 --> 00:52:28,490 difference in the distribution of Ages 1130 00:52:36,570 --> 00:52:31,730 in the galaxy okay I'm gonna skip this 1131 00:52:39,070 --> 00:52:36,580 and this actually so how do we know that 1132 00:52:42,099 --> 00:52:39,080 stars in the center of the galaxy are 1133 00:52:44,890 --> 00:52:42,109 older there's a few arguments probably 1134 00:52:46,210 --> 00:52:44,900 the the strongest argument I think is 1135 00:52:48,910 --> 00:52:46,220 this one which has been through many 1136 00:52:52,540 --> 00:52:48,920 iterations but it was done really really 1137 00:52:55,240 --> 00:52:52,550 well by my noella luckily she is an 1138 00:52:57,880 --> 00:52:55,250 Italian astronomer who now works in 1139 00:53:02,050 --> 00:52:57,890 Chile in South America and she's 1140 00:53:03,490 --> 00:53:02,060 probably contributed either the most or 1141 00:53:06,310 --> 00:53:03,500 among the most that people have 1142 00:53:07,330 --> 00:53:06,320 contributed to this field in the past 20 1143 00:53:08,530 --> 00:53:07,340 years 1144 00:53:12,760 --> 00:53:08,540 and so now we're going to look at 1145 00:53:14,890 --> 00:53:12,770 distributions of stars this is stars in 1146 00:53:18,520 --> 00:53:14,900 the solar neighborhood so you got 1147 00:53:21,670 --> 00:53:18,530 brightness here and color here we have 1148 00:53:26,710 --> 00:53:21,680 faint red stars we have bright red stars 1149 00:53:30,190 --> 00:53:26,720 and we have bright blue stars right now 1150 00:53:33,100 --> 00:53:30,200 in the balls faint red stars bright red 1151 00:53:36,820 --> 00:53:33,110 stars and four bright blue stars there's 1152 00:53:41,010 --> 00:53:36,830 nothing can anybody tell me why there 1153 00:53:44,350 --> 00:53:41,020 are no bright blue stars there yes 1154 00:53:47,440 --> 00:53:44,360 that's right so bright blue stars those 1155 00:53:51,130 --> 00:53:47,450 are a really massive stars they don't 1156 00:53:55,000 --> 00:53:51,140 live a long life right so they die 1157 00:53:57,100 --> 00:53:55,010 within like hundreds of millions of 1158 00:53:59,710 --> 00:53:57,110 years and there's just very few of them 1159 00:54:04,470 --> 00:53:59,720 in the Bulge just might be a sprinkling 1160 00:54:08,380 --> 00:54:04,480 of them but it's a tiny amount and so 1161 00:54:09,970 --> 00:54:08,390 right there's a shortage of younger 1162 00:54:11,260 --> 00:54:09,980 stars I'll skip those cool actually this 1163 00:54:14,080 --> 00:54:11,270 is just meant to show that there was a 1164 00:54:16,720 --> 00:54:14,090 consensus from various experts I'll just 1165 00:54:20,170 --> 00:54:16,730 quote mine wallows locally there since I 1166 00:54:22,720 --> 00:54:20,180 showed her work the Balch age which was 1167 00:54:24,370 --> 00:54:22,730 found to be as large of that as the 1168 00:54:27,010 --> 00:54:24,380 Galactic globular clusters were at least 1169 00:54:30,310 --> 00:54:27,020 10 billion years old so twice as old as 1170 00:54:32,860 --> 00:54:30,320 the Sun no train no trace sorry 1171 00:54:36,580 --> 00:54:32,870 not not no train it's found for any 1172 00:54:40,270 --> 00:54:36,590 younger stellar population here's a more 1173 00:54:43,450 --> 00:54:40,280 recent analysis it's a histogram done by 1174 00:54:45,640 --> 00:54:43,460 astronomers based in Sweden they use the 1175 00:54:49,720 --> 00:54:45,650 same method to look at stars near the 1176 00:54:52,690 --> 00:54:49,730 Sun here and in the Bulge here and four 1177 00:54:54,700 --> 00:54:52,700 stars near the Sun they find all ages 1178 00:54:56,770 --> 00:54:54,710 their stars of all ages which has been 1179 00:54:59,260 --> 00:54:56,780 known for a very long time but the most 1180 00:55:01,540 --> 00:54:59,270 common age is four and a half billion 1181 00:55:03,190 --> 00:55:01,550 years do you guys can think you guys 1182 00:55:05,430 --> 00:55:03,200 think of another star that's about 1183 00:55:08,680 --> 00:55:05,440 four-and-a-half billion years old 1184 00:55:10,690 --> 00:55:08,690 yeah so that's another coincidence here 1185 00:55:13,690 --> 00:55:10,700 the Sun is very typical in metallicity 1186 00:55:16,210 --> 00:55:13,700 as I mentioned earlier and it's also 1187 00:55:19,630 --> 00:55:16,220 very typical in age of the stars near it 1188 00:55:20,980 --> 00:55:19,640 it's kind of weird and for the Bulge 1189 00:55:22,930 --> 00:55:20,990 they also see 1190 00:55:25,660 --> 00:55:22,940 stars of all ages the sample is smaller 1191 00:55:30,010 --> 00:55:25,670 because it's hard harder to measure 1192 00:55:32,710 --> 00:55:30,020 those stars but there isn't as big a 1193 00:55:58,600 --> 00:55:32,720 peak at 4 Giga years it's kind of like 1194 00:56:02,950 --> 00:55:58,610 flat from 4 to 12 yes sorry can you see 1195 00:56:06,750 --> 00:56:02,960 that again oh they wouldn't have time to 1196 00:56:09,100 --> 00:56:06,760 move out for a star in a typical orbit 1197 00:56:11,710 --> 00:56:09,110 it would take several hundred million 1198 00:56:13,450 --> 00:56:11,720 years well for a Sun for example it 1199 00:56:16,090 --> 00:56:13,460 takes 200 million years to go around the 1200 00:56:17,800 --> 00:56:16,100 galaxy and that's a small and then it 1201 00:56:19,330 --> 00:56:17,810 ends up at the same spot right if you 1202 00:56:21,910 --> 00:56:19,340 want a big change you'll need a lot more 1203 00:56:24,310 --> 00:56:21,920 time than that so relative to the 1204 00:56:31,510 --> 00:56:24,320 lifetime of a blue star that's actually 1205 00:56:37,000 --> 00:56:31,520 pretty big now okay I get it 1206 00:56:39,609 --> 00:56:37,010 thank you so originally there was a lot 1207 00:56:42,040 --> 00:56:39,619 of gas there and the center of the 1208 00:56:44,740 --> 00:56:42,050 galaxy I think that's what you said had 1209 00:56:46,330 --> 00:56:44,750 a higher density of gas and it does 1210 00:56:49,930 --> 00:56:46,340 happen that when you have a higher 1211 00:56:52,540 --> 00:56:49,940 density of gas physically it gets 1212 00:56:55,210 --> 00:56:52,550 converted to stars much more efficiently 1213 00:56:58,150 --> 00:56:55,220 the more gas you have if you have like 1214 00:57:00,490 --> 00:56:58,160 three times as much gas you might form 9 1215 00:57:02,920 --> 00:57:00,500 times as many stars in a certain amount 1216 00:57:04,980 --> 00:57:02,930 of time so you do run out of gas more 1217 00:57:08,140 --> 00:57:04,990 rapidly once you run out of gas you 1218 00:57:10,150 --> 00:57:08,150 can't form stars anymore there's other 1219 00:57:16,780 --> 00:57:10,160 ways to stop forming stars but that's 1220 00:57:19,450 --> 00:57:16,790 the simplest one and all right so 1221 00:57:21,970 --> 00:57:19,460 perhaps the ages are even older I want 1222 00:57:24,160 --> 00:57:21,980 it to stop there but there was a wrinkle 1223 00:57:26,830 --> 00:57:24,170 published today and so I decided to add 1224 00:57:33,009 --> 00:57:26,840 it because it does inform our science we 1225 00:57:37,149 --> 00:57:35,259 and it's kind of flats between 4 and 12 1226 00:57:39,789 --> 00:57:37,159 Giga years right so there's already a 1227 00:57:42,159 --> 00:57:39,799 story and that it's different than what 1228 00:57:45,489 --> 00:57:42,169 we have near the Sun but how different 1229 00:57:47,019 --> 00:57:45,499 and it might be even more different than 1230 00:57:50,259 --> 00:57:47,029 they think and I happen to agree 1231 00:57:52,120 --> 00:57:50,269 personally there was a new analysis that 1232 00:57:53,739 --> 00:57:52,130 came out I think it was yesterday or the 1233 00:57:55,989 --> 00:57:53,749 day before not not yesterday I have 1234 00:57:58,299 --> 00:57:55,999 Friday or Thursday by an Italian 1235 00:57:59,889 --> 00:57:58,309 astronomer alveolar and Zini Italians 1236 00:58:01,659 --> 00:57:59,899 have contributed a lot to astronomy and 1237 00:58:06,039 --> 00:58:01,669 particularly this to this astronomy of 1238 00:58:09,159 --> 00:58:06,049 the galaxy and he says stars that are 1239 00:58:12,279 --> 00:58:09,169 less than 5 billion years old exist in 1240 00:58:15,669 --> 00:58:12,289 at most a trace amounts or not at all no 1241 00:58:18,549 --> 00:58:15,679 more than 3% of the stars and this 1242 00:58:21,699 --> 00:58:18,559 contradicts this image who's right who's 1243 00:58:24,639 --> 00:58:21,709 wrong so I think that they're wrong and 1244 00:58:27,159 --> 00:58:24,649 he's right but I cannot prove it right 1245 00:58:29,729 --> 00:58:27,169 now it's an ongoing controversy and 1246 00:58:34,569 --> 00:58:29,739 people have been going back and forth on 1247 00:58:36,099 --> 00:58:34,579 this controversy for a few years so 1248 00:58:39,339 --> 00:58:36,109 conclusions asked to the 1249 00:58:43,689 --> 00:58:39,349 characterization of the Bulge right I 1250 00:58:46,749 --> 00:58:43,699 should have brought more water sorry the 1251 00:58:49,359 --> 00:58:46,759 ball stars have a broad range in metals 1252 00:58:51,549 --> 00:58:49,369 abundance you know or you have stars 1253 00:58:54,099 --> 00:58:51,559 with very few metals stars and are like 1254 00:58:56,620 --> 00:58:54,109 the Sun and stars that have four or five 1255 00:58:59,979 --> 00:58:56,630 times more metals in the Sun it's a big 1256 00:59:01,749 --> 00:58:59,989 range and the typical value is about the 1257 00:59:04,809 --> 00:59:01,759 same iron to hydrogen ratio as a Sun 1258 00:59:06,909 --> 00:59:04,819 which is a cool coincidence but they 1259 00:59:10,689 --> 00:59:06,919 have somewhat more oxygen silicon 1260 00:59:14,379 --> 00:59:10,699 calcium relative to iron then the Sun 1261 00:59:16,989 --> 00:59:14,389 has almost all the stars in the Bulge 1262 00:59:19,419 --> 00:59:16,999 are distributed as an exceptionally 1263 00:59:21,579 --> 00:59:19,429 strong bar and my exceptionally strong I 1264 00:59:24,689 --> 00:59:21,589 mean relative to other spiral galaxies 1265 00:59:27,519 --> 00:59:24,699 in the sky half of spirals have bars 1266 00:59:29,620 --> 00:59:27,529 approximately but already it's stronger 1267 00:59:31,719 --> 00:59:29,630 than half of them but even among the 1268 00:59:34,120 --> 00:59:31,729 half that have bars very few of them 1269 00:59:36,249 --> 00:59:34,130 have a bar which is as strong as the 1270 00:59:38,649 --> 00:59:36,259 Milky Way's bar it's not clear why that 1271 00:59:40,659 --> 00:59:38,659 is on the one hand I've been telling you 1272 00:59:42,309 --> 00:59:40,669 that the Sun is typical within the Milky 1273 00:59:45,549 --> 00:59:42,319 Way but on the other hand the Milky Way 1274 00:59:46,599 --> 00:59:45,559 is a typical among galaxies should we 1275 00:59:49,660 --> 00:59:46,609 interpret that 1276 00:59:51,579 --> 00:59:49,670 or should we not I'm not sure and this 1277 00:59:53,589 --> 00:59:51,589 effect is strongest among the most 1278 00:59:54,999 --> 00:59:53,599 metal-rich stars it does suggest that 1279 01:00:00,999 --> 00:59:55,009 there hasn't been a merger here in a 1280 01:00:04,289 --> 01:00:01,009 long time a merger of galaxies and the 1281 01:00:10,210 --> 01:00:04,299 stars in the Bulge are typically older 1282 01:00:34,329 --> 01:00:10,220 than most of the stars near the Sun all 1283 01:00:36,729 --> 01:00:34,339 right that's all thank you yes okay so 1284 01:00:38,170 --> 01:00:36,739 the question is what is in the center of 1285 01:00:40,960 --> 01:00:38,180 the galaxy that causes everything to 1286 01:00:43,559 --> 01:00:40,970 spin around it yeah I'm just repeating 1287 01:00:47,920 --> 01:00:43,569 questions for the online audience there 1288 01:00:51,370 --> 01:00:47,930 so okay why do galaxies spin and have 1289 01:00:52,479 --> 01:00:51,380 angular momentum so if you spin 1290 01:00:55,779 --> 01:00:52,489 something on earth 1291 01:00:59,170 --> 01:00:55,789 it'll stop spinning do the drag but if 1292 01:01:04,239 --> 01:00:59,180 you spin something in space it will keep 1293 01:01:06,789 --> 01:01:04,249 spinning forever so if you're asking why 1294 01:01:09,849 --> 01:01:06,799 does the galaxy have angular momentum 1295 01:01:11,620 --> 01:01:09,859 it's kind of a random thing some 1296 01:01:14,259 --> 01:01:11,630 galaxies have very little angular 1297 01:01:17,470 --> 01:01:14,269 momentum some have a lot in one 1298 01:01:21,009 --> 01:01:17,480 direction and some have a lot in the 1299 01:01:23,950 --> 01:01:21,019 other direction and so it just happens 1300 01:01:25,450 --> 01:01:23,960 that we live in one that has a lot in 1301 01:01:29,440 --> 01:01:25,460 its current direction but if you take 1302 01:01:33,160 --> 01:01:29,450 the sum of spin of all the galaxies it 1303 01:01:36,009 --> 01:01:33,170 has to add up to zero kurz Goodell who's 1304 01:01:37,599 --> 01:01:36,019 a mathematician who contribute a lot to 1305 01:01:39,880 --> 01:01:37,609 our understanding of logic actually 1306 01:01:43,680 --> 01:01:39,890 showed in the mid twentieth century that 1307 01:01:46,720 --> 01:01:43,690 if the universe as a whole was spinning 1308 01:01:48,880 --> 01:01:46,730 then not only would time-travel be 1309 01:01:51,430 --> 01:01:48,890 possible but it would be necessary and 1310 01:01:54,910 --> 01:01:51,440 happening all the time and we'd have 1311 01:01:56,349 --> 01:01:54,920 causal loops going on maybe that's true 1312 01:01:58,150 --> 01:01:56,359 and we don't realize it for pi the 1313 01:01:59,779 --> 01:01:58,160 universe as a whole is not spinning oh 1314 01:02:15,199 --> 01:01:59,789 yeah 1315 01:02:17,569 --> 01:02:15,209 okay so many questions so there is this 1316 01:02:19,609 --> 01:02:17,579 gentleman there was a there's a black 1317 01:02:21,829 --> 01:02:19,619 hole in the center of these galaxies how 1318 01:02:23,329 --> 01:02:21,839 does that affect the Bulge I'm sorry I 1319 01:02:24,529 --> 01:02:23,339 didn't repeat the last question thank 1320 01:02:31,729 --> 01:02:24,539 you 1321 01:02:34,309 --> 01:02:31,739 major topic of research in astronomy 1322 01:02:36,919 --> 01:02:34,319 it's probably 10% of the papers that are 1323 01:02:39,889 --> 01:02:36,929 published debating that point so I 1324 01:02:42,049 --> 01:02:39,899 cannot give you an answer I can give you 1325 01:02:45,079 --> 01:02:42,059 some of the answers that people have 1326 01:02:48,439 --> 01:02:45,089 suggested so the Milky Way does have a 1327 01:02:51,129 --> 01:02:48,449 black hole in its center it's about four 1328 01:02:53,929 --> 01:02:51,139 million times more massive than the Sun 1329 01:02:56,599 --> 01:02:53,939 it's pretty big and it does turn out 1330 01:02:59,269 --> 01:02:56,609 that four galaxies the properties of 1331 01:03:02,049 --> 01:02:59,279 black hole are tightly correlated with 1332 01:03:04,759 --> 01:03:02,059 the properties of the galaxy as a whole 1333 01:03:07,879 --> 01:03:04,769 some people say that's a coincidence and 1334 01:03:10,669 --> 01:03:07,889 some people say that's a causal link 1335 01:03:12,979 --> 01:03:10,679 it's not clear who's right and who's 1336 01:03:15,889 --> 01:03:12,989 wrong what could be the case for example 1337 01:03:17,959 --> 01:03:15,899 is that maybe you go back to the movie 1338 01:03:20,509 --> 01:03:17,969 at the start of the prudhoe galaxies 1339 01:03:22,939 --> 01:03:20,519 merging maybe all proto galaxies 1340 01:03:25,309 --> 01:03:22,949 themselves have black holes and so when 1341 01:03:28,909 --> 01:03:25,319 they merge their black holes Cora last 1342 01:03:31,069 --> 01:03:28,919 is center and that's and so and then 1343 01:03:33,319 --> 01:03:31,079 eventually the bigger galaxies which 1344 01:03:35,209 --> 01:03:33,329 were formed from more mergers also have 1345 01:03:38,749 --> 01:03:35,219 big or black holes at their center but 1346 01:03:40,639 --> 01:03:38,759 there's huge scatter there but there 1347 01:03:43,129 --> 01:03:40,649 will be much better measurements of that 1348 01:03:44,899 --> 01:03:43,139 this year the way that's measured there 1349 01:03:46,849 --> 01:03:44,909 happens to be we're very lucky there's a 1350 01:03:50,120 --> 01:03:46,859 star that passes very close to the black 1351 01:03:53,479 --> 01:03:50,130 hole it's on an elliptical orbit and so 1352 01:03:55,309 --> 01:03:53,489 it passes closest sometime this year and 1353 01:03:55,789 --> 01:03:55,319 they're taking a lot of images of it 1354 01:03:57,589 --> 01:03:55,799 right now 1355 01:03:59,479 --> 01:03:57,599 and we'll have much more detail on the 1356 01:04:01,370 --> 01:03:59,489 black hole that will probably be one of 1357 01:04:02,599 --> 01:04:01,380 the next year's public talks it 1358 01:04:10,160 --> 01:04:02,609 certainly hope so yeah that's an 1359 01:04:15,430 --> 01:04:11,809 see how do they relate to each of it 1360 01:04:18,380 --> 01:04:15,440 this is the black hole inside the bar 1361 01:04:20,089 --> 01:04:18,390 yes how does the black hole at the 1362 01:04:21,440 --> 01:04:20,099 center of the galaxy and the bar the 1363 01:04:25,190 --> 01:04:21,450 center of the galaxy relate to each 1364 01:04:26,870 --> 01:04:25,200 other so geometrically the black hole is 1365 01:04:29,660 --> 01:04:26,880 approximately the size of the solar 1366 01:04:32,660 --> 01:04:29,670 system and it's four million times more 1367 01:04:38,059 --> 01:04:32,670 mass in the Sun it defines the center of 1368 01:04:41,420 --> 01:04:38,069 the galaxy the bar itself is not the 1369 01:04:43,519 --> 01:04:41,430 size or source system it's maybe so half 1370 01:04:47,539 --> 01:04:43,529 the length the bar as in from the middle 1371 01:04:50,539 --> 01:04:47,549 to the end is about thirteen thousand 1372 01:04:54,799 --> 01:04:50,549 light-years so it's far bigger and the 1373 01:04:57,589 --> 01:04:54,809 bar as a whole is about twenty billion 1374 01:05:01,430 --> 01:04:57,599 solar masses so it's a totally different 1375 01:05:03,589 --> 01:05:01,440 scale but the the supermassive black 1376 01:05:05,359 --> 01:05:03,599 hole should be at the center that said 1377 01:05:07,870 --> 01:05:05,369 you can always define the center of a 1378 01:05:10,549 --> 01:05:07,880 circle or the center of a square a 1379 01:05:13,370 --> 01:05:10,559 galaxy doesn't have a very precise shape 1380 01:05:16,940 --> 01:05:13,380 so this the meaning of the center isn't 1381 01:05:31,999 --> 01:05:16,950 perfect whew yes way back in the corner 1382 01:05:33,710 --> 01:05:32,009 there I say the question was you said 1383 01:05:35,359 --> 01:05:33,720 that a black hole of a supermassive 1384 01:05:36,019 --> 01:05:35,369 black hole is about the size of a solar 1385 01:05:38,210 --> 01:05:36,029 system 1386 01:05:40,249 --> 01:05:38,220 he thinks that black holes don't take up 1387 01:05:41,809 --> 01:05:40,259 any space can you clarify that 1388 01:05:45,440 --> 01:05:41,819 all right that's a very good question 1389 01:05:50,059 --> 01:05:45,450 thank you and so it depends how you 1390 01:05:54,410 --> 01:05:50,069 define it so black holes in pop culture 1391 01:05:56,599 --> 01:05:54,420 and also in a lot of physics are just a 1392 01:06:00,440 --> 01:05:56,609 single arity at the center which is 1393 01:06:03,380 --> 01:06:00,450 exactly it's a point of no space and the 1394 01:06:05,990 --> 01:06:03,390 point of infinite density another way to 1395 01:06:09,230 --> 01:06:06,000 define a black hole is in terms of an 1396 01:06:10,970 --> 01:06:09,240 event horizon and that's where if you 1397 01:06:13,249 --> 01:06:10,980 get close enough to the black hole 1398 01:06:13,579 --> 01:06:13,259 nobody is ever going to hear from you 1399 01:06:16,279 --> 01:06:13,589 again 1400 01:06:19,430 --> 01:06:16,289 and you're done it's the point of no 1401 01:06:21,410 --> 01:06:19,440 turning back and so that defines a 1402 01:06:23,150 --> 01:06:21,420 radius which for the black hole the 1403 01:06:23,740 --> 01:06:23,160 center of the galaxy is about the size 1404 01:06:27,100 --> 01:06:23,750 of the source 1405 01:06:29,140 --> 01:06:27,110 if the Sun was a black hole that radius 1406 01:06:30,880 --> 01:06:29,150 would be three kilometers I think or is 1407 01:06:33,940 --> 01:06:30,890 it one and a half kilometers I think 1408 01:06:34,900 --> 01:06:33,950 three kilometers okay the other question 1409 01:06:38,470 --> 01:06:34,910 in the back there 1410 01:06:44,260 --> 01:06:38,480 yes you so you said that starts in the 1411 01:06:46,900 --> 01:06:44,270 bolger RM in average older than those we 1412 01:06:49,900 --> 01:06:46,910 have at next door yes does that mean 1413 01:06:52,540 --> 01:06:49,910 that when in the far future when those 1414 01:06:54,580 --> 01:06:52,550 stars in the boobs will have died there 1415 01:07:03,190 --> 01:06:54,590 will be a mostly empty space in the 1416 01:07:05,350 --> 01:07:03,200 middle it'll look like empty space but 1417 01:07:09,070 --> 01:07:05,360 when stars die they leave behind 1418 01:07:12,040 --> 01:07:09,080 remnants typically called white dwarfs a 1419 01:07:15,100 --> 01:07:12,050 white dwarf might be like typically half 1420 01:07:18,520 --> 01:07:15,110 the mass of the original star but it's 1421 01:07:20,890 --> 01:07:18,530 the old core of the star and it's about 1422 01:07:24,040 --> 01:07:20,900 the size of the earth and it's very 1423 01:07:26,230 --> 01:07:24,050 faint so you'll have a bunch of dark 1424 01:07:27,670 --> 01:07:26,240 remnants and aside from the white dwarfs 1425 01:07:30,070 --> 01:07:27,680 there will be like millions or billions 1426 01:07:31,600 --> 01:07:30,080 of black holes that are much smaller 1427 01:07:33,100 --> 01:07:31,610 than a supermassive black hole at the 1428 01:07:36,370 --> 01:07:33,110 center of galaxies but still pretty big 1429 01:07:37,540 --> 01:07:36,380 so it'll look like empty space that's a 1430 01:07:39,670 --> 01:07:37,550 great question actually I'll go back to 1431 01:07:42,370 --> 01:07:39,680 the beginning oh where is it where's 1432 01:07:44,950 --> 01:07:42,380 that photo artist's rendition instead of 1433 01:07:47,170 --> 01:07:44,960 this being yellow it'll look black but 1434 01:07:55,240 --> 01:07:47,180 there will be a ton of objects down I 1435 01:08:04,090 --> 01:07:55,250 have about the same amount of mass what 1436 01:08:08,980 --> 01:08:06,640 I'm not sure if there is a precise 1437 01:08:10,900 --> 01:08:08,990 definition of the edge and I know for 1438 01:08:13,570 --> 01:08:10,910 example at a conference that I went to a 1439 01:08:16,030 --> 01:08:13,580 couple years ago they debated what is 1440 01:08:18,610 --> 01:08:16,040 the mass of the galaxy and that depends 1441 01:08:20,440 --> 01:08:18,620 how far out you go because it just keeps 1442 01:08:22,510 --> 01:08:20,450 adding more mass as you go further out 1443 01:08:24,190 --> 01:08:22,520 and eventually you're like an 1444 01:08:25,780 --> 01:08:24,200 intergalactic space and you have one 1445 01:08:27,820 --> 01:08:25,790 point that might be closer to another 1446 01:08:30,340 --> 01:08:27,830 galaxy and then you move in some other 1447 01:08:34,030 --> 01:08:30,350 direction and it's not clear there's no 1448 01:08:36,670 --> 01:08:34,040 border so in Star Trek 1449 01:08:39,820 --> 01:08:36,680 for example there's like borders and 1450 01:08:42,760 --> 01:08:39,830 interstellar space and they police them 1451 01:08:47,170 --> 01:08:42,770 or even in did anyone watch Battlestar 1452 01:08:49,630 --> 01:08:47,180 Galactica it was a Cylon armistice line 1453 01:08:52,360 --> 01:08:49,640 and that was brought back so it's like a 1454 01:08:54,610 --> 01:08:52,370 line in space but I'm not sure how that 1455 01:08:58,570 --> 01:08:54,620 would work and that'd be like a huge 1456 01:09:00,310 --> 01:08:58,580 area to patrol this audience learned a 1457 01:09:02,410 --> 01:09:00,320 few months ago the size of the 1458 01:09:04,690 --> 01:09:02,420 Federation space and Star Trek is only 1459 01:09:07,450 --> 01:09:04,700 like 200 light-years across I thought it 1460 01:09:10,450 --> 01:09:07,460 was a whole awful hundred light-years 1461 01:09:13,060 --> 01:09:10,460 it's really crazy and I would also add 1462 01:09:14,680 --> 01:09:13,070 that the edge of the galaxy is defined 1463 01:09:16,990 --> 01:09:14,690 differently by different astronomers 1464 01:09:20,080 --> 01:09:17,000 visible light astronomers might do one 1465 01:09:21,820 --> 01:09:20,090 thing h1 astronomers radio astronomers 1466 01:09:23,890 --> 01:09:21,830 would do another thing in terms of the 1467 01:09:25,660 --> 01:09:23,900 edge yeah he's right there's just a lot 1468 01:09:29,890 --> 01:09:25,670 of different variations we have a 1469 01:09:32,950 --> 01:09:29,900 question from online let's see what the 1470 01:09:37,210 --> 01:09:32,960 ramifications are two bulges colliding 1471 01:09:40,840 --> 01:09:37,220 reclining galaxies that's a great 1472 01:09:44,140 --> 01:09:40,850 question and its relevance but one of 1473 01:09:46,840 --> 01:09:44,150 the reasons it's relevant is that it may 1474 01:09:49,330 --> 01:09:46,850 happen in a few billion years here when 1475 01:09:52,320 --> 01:09:49,340 the Milky Way and Andromeda are very 1476 01:09:54,940 --> 01:09:52,330 likely to merge so it does depend on the 1477 01:09:57,700 --> 01:09:54,950 configuration that they have and whether 1478 01:09:59,200 --> 01:09:57,710 it's like head-on or just like skidding 1479 01:10:01,330 --> 01:09:59,210 each other because it could be any 1480 01:10:04,320 --> 01:10:01,340 configuration but typically they will 1481 01:10:07,240 --> 01:10:04,330 end up forming a bigger bulge and 1482 01:10:09,430 --> 01:10:07,250 statistically what happens is that stars 1483 01:10:11,890 --> 01:10:09,440 that were in the center of their 1484 01:10:14,470 --> 01:10:11,900 respective bulges will also be in the 1485 01:10:15,880 --> 01:10:14,480 center of the combined bulge and stars 1486 01:10:16,430 --> 01:10:15,890 that were in the outskirts of the 1487 01:10:19,130 --> 01:10:16,440 respect 1488 01:10:20,720 --> 01:10:19,140 we'll also be in the outskirts of their 1489 01:10:23,959 --> 01:10:20,730 combined ball just need how that works 1490 01:10:30,410 --> 01:10:23,969 out all right other questions from here 1491 01:10:32,060 --> 01:10:30,420 is there any evidence is there any 1492 01:10:37,120 --> 01:10:32,070 evidence that our galaxy is already 1493 01:10:39,740 --> 01:10:37,130 collided with another galaxy yes so I 1494 01:10:42,080 --> 01:10:39,750 showed you the movies to start so you 1495 01:10:44,630 --> 01:10:42,090 could argue that's evidence because 1496 01:10:45,890 --> 01:10:44,640 within cosmological simulations that 1497 01:10:47,720 --> 01:10:45,900 start with our understanding of the 1498 01:10:50,120 --> 01:10:47,730 universe galaxies are formed from 1499 01:10:51,650 --> 01:10:50,130 mergers of proto galaxies but maybe you 1500 01:10:55,160 --> 01:10:51,660 want more evidence to that and so the 1501 01:10:58,550 --> 01:10:55,170 best evidence we have is that we do see 1502 01:11:00,439 --> 01:10:58,560 a few small streams around the Milky Way 1503 01:11:02,540 --> 01:11:00,449 which are they're not shown in this 1504 01:11:08,570 --> 01:11:02,550 image I don't know if they're shown in 1505 01:11:14,090 --> 01:11:08,580 any of the other images see I'll try and 1506 01:11:21,979 --> 01:11:14,100 see if there's one somewhere okay and 1507 01:11:23,540 --> 01:11:21,989 HAP may be actually okay so it happens 1508 01:11:25,700 --> 01:11:23,550 that there's no streams anywhere but 1509 01:11:28,189 --> 01:11:25,710 around the Milky Way we actually do see 1510 01:11:30,680 --> 01:11:28,199 a few weak streams which are due to 1511 01:11:32,780 --> 01:11:30,690 active accretion of smaller galaxies but 1512 01:11:36,979 --> 01:11:32,790 these are very minor mergers happening 1513 01:11:38,689 --> 01:11:36,989 it's like a 100 to 1 ratio and whereas 1514 01:11:40,490 --> 01:11:38,699 in simulations we expect that at some 1515 01:11:43,250 --> 01:11:40,500 point there should be two to one ratio 1516 01:11:44,990 --> 01:11:43,260 mergers 3 to 1 ratio mergers and so on 1517 01:11:48,080 --> 01:11:45,000 the mergers that we're seeing in the 1518 01:11:52,580 --> 01:11:48,090 Milky Way now are in the very very minor 1519 01:11:56,209 --> 01:11:52,590 merger regime as it's called ok and we 1520 01:11:58,670 --> 01:11:56,219 have one last question from online how 1521 01:12:00,590 --> 01:11:58,680 old is the oldest star in the Milky Way 1522 01:12:05,330 --> 01:12:00,600 and how does that compare to the age of 1523 01:12:08,150 --> 01:12:05,340 the universe so that is a very good 1524 01:12:11,420 --> 01:12:08,160 question as well and the answer is that 1525 01:12:13,550 --> 01:12:11,430 we can't know that that well because 1526 01:12:16,490 --> 01:12:13,560 ages of stars are only measured to about 1527 01:12:18,680 --> 01:12:16,500 10% precision or so and because of that 1528 01:12:21,920 --> 01:12:18,690 we actually have stars for which the 1529 01:12:24,620 --> 01:12:21,930 best estimate of the age is older than 1530 01:12:27,140 --> 01:12:24,630 the age of the universe but that's fine 1531 01:12:28,920 --> 01:12:27,150 because we know that's what the 1532 01:12:31,290 --> 01:12:28,930 measurement error is 1533 01:12:34,470 --> 01:12:31,300 and so we're okay with that but 1534 01:12:35,970 --> 01:12:34,480 eventually as ages improve we should not 1535 01:12:37,830 --> 01:12:35,980 have any stars older in the age of 1536 01:12:40,200 --> 01:12:37,840 universe and one thing that we'd like to 1537 01:12:42,240 --> 01:12:40,210 find out and for which Baltimore 1538 01:12:44,490 --> 01:12:42,250 astronomers will take a leading role is 1539 01:12:46,380 --> 01:12:44,500 when did the first stars in the universe 1540 01:12:48,270 --> 01:12:46,390 form was it a hundred million years 1541 01:12:50,760 --> 01:12:48,280 after the Big Bang two hundred million 1542 01:12:55,860 --> 01:12:50,770 years after the Big Bang that is an open 1543 01:12:57,810 --> 01:12:55,870 topic which may be the James Webb Space 1544 01:13:00,150 --> 01:12:57,820 Telescope mentioned by Frank earlier 1545 01:13:02,160 --> 01:13:00,160 will help us solve within a year or two 1546 01:13:05,610 --> 01:13:02,170 it's one of the points of the James Webb 1547 01:13:17,460 --> 01:13:05,620 Space Telescope okay and in the back 1548 01:13:18,860 --> 01:13:17,470 corner so if Andromeda look we're gonna 1549 01:13:21,030 --> 01:13:18,870 combine does that mean that the 1550 01:13:21,720 --> 01:13:21,040 Andromeda has a blue shift relative to 1551 01:13:24,210 --> 01:13:21,730 the Milky Way 1552 01:13:26,760 --> 01:13:24,220 yeah it does it's one of the few blue 1553 01:13:39,660 --> 01:13:26,770 shifted galaxies we have one more 1554 01:13:43,890 --> 01:13:39,670 question here typically they will end up 1555 01:13:46,080 --> 01:13:43,900 sinking faster too because they're more 1556 01:13:47,880 --> 01:13:46,090 massive they will end up sinking faster 1557 01:13:51,990 --> 01:13:47,890 and then you'll also have a merger of 1558 01:13:53,970 --> 01:13:52,000 your black holes eventually and that'll 1559 01:13:57,390 --> 01:13:53,980 make big gravitational waves the most 1560 01:13:59,640 --> 01:13:57,400 energetic events in the universe within 1561 01:14:01,470 --> 01:13:59,650 pop-culture knowledge it might be 1562 01:14:03,090 --> 01:14:01,480 believed to be supernova but it's 1563 01:14:05,430 --> 01:14:03,100 actually the mergers of supermassive 1564 01:14:08,460 --> 01:14:05,440 black holes where the energy comes down 1565 01:14:10,710 --> 01:14:08,470 in gravitational waves and eventually 1566 01:14:13,050 --> 01:14:10,720 they merge but I might be like some 1567 01:14:14,640 --> 01:14:13,060 billion years after the galaxies 1568 01:14:16,950 --> 01:14:14,650 themselves approached because it'll take 1569 01:14:19,140 --> 01:14:16,960 time for the smaller black hole to make 1570 01:14:21,750 --> 01:14:19,150 it to the center of gravity and 1571 01:14:24,300 --> 01:14:21,760 encounter the bigger black hole all 1572 01:14:26,460 --> 01:14:24,310 right we're gonna end it there ireenie 1573 01:14:28,170 --> 01:14:26,470 are you here anybody from the Maryland 1574 01:14:30,930 --> 01:14:28,180 Space Grant Observatory here to take 1575 01:14:32,700 --> 01:14:30,940 people across the street I guess not so 1576 01:14:33,780 --> 01:14:32,710 there will be no observing across the 1577 01:14:34,590 --> 01:14:33,790 street with the Maryland Space Grant 1578 01:14:36,270 --> 01:14:34,600 observatory 1579 01:14:38,940 --> 01:14:36,280 please check their website for their 1580 01:14:41,220 --> 01:14:38,950 Friday night open houses next month 1581 01:14:43,560 --> 01:14:41,230 August 7th ashes to 1582 01:14:45,900 --> 01:14:43,570 ashes dust to dust the fate of stars 1583 01:14:48,360 --> 01:14:45,910 like the Sun you want to know how the 1584 01:14:50,580 --> 01:14:48,370 story ends for our Sun you got to come 1585 01:14:50,970 --> 01:14:50,590 next month let's give another great big