1 00:00:06,019 --> 00:00:03,220 I to study cosmology all right in 2 00:00:07,820 --> 00:00:06,029 December Christine Chen will be talking 3 00:00:11,450 --> 00:00:07,830 about debris disks and the evolution of 4 00:00:14,450 --> 00:00:11,460 planetary systems yet another one of the 5 00:00:16,640 --> 00:00:14,460 hot topics in astronomy talking about 6 00:00:19,640 --> 00:00:16,650 extrasolar planets and how planetary 7 00:00:24,950 --> 00:00:19,650 systems develop I mean I remember when I 8 00:00:26,450 --> 00:00:24,960 was a wee lad just an undergraduate we 9 00:00:28,550 --> 00:00:26,460 knew nothing about how planetary systems 10 00:00:30,470 --> 00:00:28,560 develop and the amount that we know now 11 00:00:31,540 --> 00:00:30,480 is just amazing it's one of the one of 12 00:00:33,889 --> 00:00:31,550 the great topics 13 00:00:38,389 --> 00:00:33,899 unfortunately in January we have our 14 00:00:40,160 --> 00:00:38,399 favors speaker TBA because it's hard to 15 00:00:42,950 --> 00:00:40,170 get somebody just after New Year's I 16 00:00:45,290 --> 00:00:42,960 wanted to ask Li asked a question folks 17 00:00:48,200 --> 00:00:45,300 would you prefer that we delayed this 18 00:00:51,080 --> 00:00:48,210 until January 10th instead of January 19 00:00:51,920 --> 00:00:51,090 3rd or would that or would that not make 20 00:00:55,180 --> 00:00:51,930 a difference 21 00:00:57,590 --> 00:00:55,190 anybody think it would be good to delay 22 00:01:00,529 --> 00:00:57,600 anybody okay with everybody would just 23 00:01:03,920 --> 00:01:00,539 think the third is better and who 24 00:01:06,880 --> 00:01:03,930 doesn't really care okay overwhelming 25 00:01:10,539 --> 00:01:06,890 don't care a little bit towards the 26 00:01:12,980 --> 00:01:10,549 towards the January 10th because the 27 00:01:15,260 --> 00:01:12,990 American Astronomical Society meets the 28 00:01:16,789 --> 00:01:15,270 first week of January and I often have 29 00:01:19,490 --> 00:01:16,799 trouble getting speakers because half 30 00:01:22,940 --> 00:01:19,500 the Institute is out at the conference 31 00:01:25,640 --> 00:01:22,950 so I might some I might consider 32 00:01:27,350 --> 00:01:25,650 delaying that all right oh the 33 00:01:28,850 --> 00:01:27,360 construction update hopefully you guys 34 00:01:30,469 --> 00:01:28,860 had to come a different way to get here 35 00:01:32,870 --> 00:01:30,479 hopefully obviously you made it 36 00:01:34,429 --> 00:01:32,880 hopefully there isn't another 50 people 37 00:01:37,039 --> 00:01:34,439 out there getting lost 38 00:01:40,700 --> 00:01:37,049 if so hopefully they will find their way 39 00:01:44,210 --> 00:01:40,710 in you have to come from the south 40 00:01:47,179 --> 00:01:44,220 because north of it is closed here is 41 00:01:49,280 --> 00:01:47,189 the map this blue part is the stuff 42 00:01:51,469 --> 00:01:49,290 that's done looks real nice especially 43 00:01:53,660 --> 00:01:51,479 this path along here is a really nice 44 00:01:56,149 --> 00:01:53,670 little path if you see it when you're 45 00:01:58,969 --> 00:01:56,159 during the daylight but this yellow 46 00:02:01,670 --> 00:01:58,979 section here and this red section up 47 00:02:03,920 --> 00:02:01,680 here those are now closed and will be 48 00:02:05,810 --> 00:02:03,930 through December ok so for the next 49 00:02:08,540 --> 00:02:05,820 several months you'll have to approach 50 00:02:12,140 --> 00:02:08,550 from the south it definitely has length 51 00:02:13,460 --> 00:02:12,150 into my commute our website with 52 00:02:15,440 --> 00:02:13,470 information 53 00:02:17,180 --> 00:02:15,450 is if you look if you just take your 54 00:02:19,850 --> 00:02:17,190 favorite search engine and look for 55 00:02:22,790 --> 00:02:19,860 Hubble public talks you'll find it we 56 00:02:25,670 --> 00:02:22,800 have links to our live webcasting both 57 00:02:28,070 --> 00:02:25,680 on YouTube and on the STScI webcasting 58 00:02:30,020 --> 00:02:28,080 site our archives of the past lectures 59 00:02:32,270 --> 00:02:30,030 again on YouTube and the STScI 60 00:02:34,610 --> 00:02:32,280 webcasting and a feature that has been 61 00:02:37,220 --> 00:02:34,620 used an awful lot because I get an email 62 00:02:39,680 --> 00:02:37,230 every time it is used people signing up 63 00:02:42,280 --> 00:02:39,690 for our announcements 64 00:02:45,110 --> 00:02:42,290 thank you all for signing up but it 65 00:02:47,120 --> 00:02:45,120 makes my job a lot easier in getting the 66 00:02:49,190 --> 00:02:47,130 information out to people not only 67 00:02:51,800 --> 00:02:49,200 around the Baltimore area but across the 68 00:02:54,980 --> 00:02:51,810 country we also of course have our list 69 00:02:57,050 --> 00:02:54,990 of upcoming lectures so visit our 70 00:03:00,170 --> 00:02:57,060 website to find that all that wonderful 71 00:03:02,000 --> 00:03:00,180 information announcements well I'll just 72 00:03:04,520 --> 00:03:02,010 use our website because there is mail 73 00:03:07,340 --> 00:03:04,530 list at STScI dat edu but it's much more 74 00:03:09,170 --> 00:03:07,350 difficult just use our website if you 75 00:03:12,430 --> 00:03:09,180 want to contact us you can send an email 76 00:03:16,460 --> 00:03:12,440 to public lecture at stsci edu ask 77 00:03:19,160 --> 00:03:16,470 comments or questions we are also on 78 00:03:22,850 --> 00:03:19,170 social media Facebook to Twitter 79 00:03:24,949 --> 00:03:22,860 accounts Google Pinterest I will note 80 00:03:26,720 --> 00:03:24,959 that my Hubble's universe unfiltered 81 00:03:30,050 --> 00:03:26,730 blog and Hubble site is getting updated 82 00:03:31,970 --> 00:03:30,060 more frequently we have it's the new 83 00:03:33,620 --> 00:03:31,980 fiscal year the funding for this fiscal 84 00:03:36,770 --> 00:03:33,630 year has enabled me to put more time 85 00:03:39,500 --> 00:03:36,780 into my blog I'm putting I put up three 86 00:03:42,050 --> 00:03:39,510 posts last month I also do Facebook 87 00:03:45,110 --> 00:03:42,060 Google and Twitter every now and then I 88 00:03:48,979 --> 00:03:45,120 don't promise to be daily at all hunt 89 00:03:50,720 --> 00:03:48,989 something like that Observatory I do not 90 00:03:52,670 --> 00:03:50,730 I didn't check my email late this 91 00:03:57,229 --> 00:03:52,680 afternoon the person from the 92 00:03:59,630 --> 00:03:57,239 observatory is obviously not here remind 93 00:04:01,400 --> 00:03:59,640 me to ask again at the end to see if 94 00:04:05,479 --> 00:04:01,410 they are here to take us up to the 95 00:04:09,380 --> 00:04:05,489 observatory tonight okay and now news 96 00:04:15,380 --> 00:04:09,390 from the universe for October 2016 97 00:04:17,360 --> 00:04:15,390 our first story lovely plumage on Europa 98 00:04:21,140 --> 00:04:17,370 how many of you recognize the phrase 99 00:04:23,270 --> 00:04:21,150 lovely plumage alright oh not that many 100 00:04:26,510 --> 00:04:23,280 oh oh this isn't a reference for this 101 00:04:27,090 --> 00:04:26,520 audience all right this is from the dead 102 00:04:30,050 --> 00:04:27,100 parrot 103 00:04:32,610 --> 00:04:30,060 sketch of Monty Python's Flying Circus 104 00:04:35,400 --> 00:04:32,620 where John Cleese's 105 00:04:37,980 --> 00:04:35,410 customer comes in to return a parrot 106 00:04:40,620 --> 00:04:37,990 that is dead and Michael Palin as the 107 00:04:42,330 --> 00:04:40,630 shop owner tries to refuse to 108 00:04:45,240 --> 00:04:42,340 acknowledge that the parrot is dead 109 00:04:48,540 --> 00:04:45,250 saying all the Norwegian blues lovely 110 00:04:51,030 --> 00:04:48,550 plumage and just talks about how it is 111 00:04:54,570 --> 00:04:51,040 you know you know it's just resting it's 112 00:04:57,420 --> 00:04:54,580 pining for the fjords and such this is 113 00:05:00,150 --> 00:04:57,430 an extremely famous sketch amongst Monty 114 00:05:03,630 --> 00:05:00,160 Python fans so much so that when Monty 115 00:05:08,360 --> 00:05:03,640 Python had a reunion in London it was 116 00:05:13,620 --> 00:05:08,370 celebrated with a 50-foot dead parrot 117 00:05:15,060 --> 00:05:13,630 the Tower Bridge so lovely plumage has 118 00:05:19,200 --> 00:05:15,070 very little to do with this story I just 119 00:05:24,900 --> 00:05:19,210 wanted to show this image but the plumes 120 00:05:27,930 --> 00:05:24,910 on Europa are these and they're not 121 00:05:29,820 --> 00:05:27,940 really quite so lovely to look at 122 00:05:33,240 --> 00:05:29,830 matter of fact you may not even see them 123 00:05:36,240 --> 00:05:33,250 unless I put in the arrows okay all 124 00:05:38,700 --> 00:05:36,250 right so this is a an image of Europa 125 00:05:41,550 --> 00:05:38,710 from the Galileo mission it's a a mosaic 126 00:05:44,070 --> 00:05:41,560 put together and these are the plumes 127 00:05:47,430 --> 00:05:44,080 down here in white the background is 128 00:05:49,470 --> 00:05:47,440 from the Hubble instrument okay oh and 129 00:05:51,270 --> 00:05:49,480 you're seeing this white stuff down here 130 00:05:55,620 --> 00:05:51,280 and it's kind of pixelated and stuff and 131 00:05:59,310 --> 00:05:55,630 I wouldn't call it lovely they're kind 132 00:06:02,490 --> 00:05:59,320 of ratty except there is a really lovely 133 00:06:04,680 --> 00:06:02,500 science story behind it so let me 134 00:06:07,440 --> 00:06:04,690 explain the science behind it and you'll 135 00:06:10,290 --> 00:06:07,450 see how beautiful they really can be so 136 00:06:12,690 --> 00:06:10,300 this is Jupiter's moon Europa it's the 137 00:06:16,110 --> 00:06:12,700 smallest of the four Galilean moons okay 138 00:06:20,370 --> 00:06:16,120 and we believe its interior structure 139 00:06:20,730 --> 00:06:20,380 has an iron core metallic core it has a 140 00:06:24,780 --> 00:06:20,740 whoops 141 00:06:29,280 --> 00:06:24,790 it has a rocky section and then it has 142 00:06:32,040 --> 00:06:29,290 an liquid water ocean and an icy crust 143 00:06:35,070 --> 00:06:32,050 okay due to various measurements in the 144 00:06:38,300 --> 00:06:35,080 magnetic field of motion to it we 145 00:06:40,830 --> 00:06:38,310 believe there is a liquid water ocean 146 00:06:44,250 --> 00:06:40,840 subsurface on Europa 147 00:06:47,250 --> 00:06:44,260 the question is is how thick is this ice 148 00:06:49,560 --> 00:06:47,260 layer is it 10 kilometers thick or is it 149 00:06:51,420 --> 00:06:49,570 100 kilometers thick we're not exactly 150 00:06:55,050 --> 00:06:51,430 sure there are two camps that argue 151 00:06:58,200 --> 00:06:55,060 about this but when we look at Europa's 152 00:07:02,010 --> 00:06:58,210 surface this is your opus surface we see 153 00:07:04,170 --> 00:07:02,020 a modeled ice sea surface and this is 154 00:07:06,900 --> 00:07:04,180 the famous ice rafts picture taken by 155 00:07:10,050 --> 00:07:06,910 the Galileo satellite which looks a lot 156 00:07:13,920 --> 00:07:10,060 like the broken ice structures in around 157 00:07:15,659 --> 00:07:13,930 the North Pole okay on earth indicating 158 00:07:18,870 --> 00:07:15,669 that there might be the same sort of 159 00:07:21,750 --> 00:07:18,880 motion of you know perhaps not on top of 160 00:07:23,129 --> 00:07:21,760 a shallow water layer just underneath as 161 00:07:25,440 --> 00:07:23,139 we have here on earth 162 00:07:26,820 --> 00:07:25,450 but that there might be softer ice and 163 00:07:30,060 --> 00:07:26,830 there's some sort of motion there's some 164 00:07:34,440 --> 00:07:30,070 breakup and a in motion through it okay 165 00:07:38,820 --> 00:07:34,450 we have evidence of motion of were sort 166 00:07:40,290 --> 00:07:38,830 of ice tectonics on Europa and it's look 167 00:07:43,409 --> 00:07:40,300 and it's something like this where we've 168 00:07:46,260 --> 00:07:43,419 got these subsumption bands here what we 169 00:07:49,409 --> 00:07:46,270 believe is happening is the cold outer 170 00:07:51,110 --> 00:07:49,419 ice shell is actually subducting just 171 00:07:53,850 --> 00:07:51,120 like the plates abduct on earth 172 00:07:57,540 --> 00:07:53,860 subducting below another ice layer 173 00:08:00,570 --> 00:07:57,550 alright and so this is denser and it 174 00:08:03,120 --> 00:08:00,580 drops down into the deeper warmer ice 175 00:08:05,460 --> 00:08:03,130 okay and notice that they call this the 176 00:08:07,529 --> 00:08:05,470 connecting portion of the ice shell 177 00:08:10,290 --> 00:08:07,539 alright we sort of think of ice as rigid 178 00:08:12,659 --> 00:08:10,300 and fixed but on your rope but there 179 00:08:14,940 --> 00:08:12,669 actually is motion through the ice and 180 00:08:17,430 --> 00:08:14,950 they talk about it convecting with the 181 00:08:20,520 --> 00:08:17,440 liquid ocean being underneath that ice 182 00:08:23,580 --> 00:08:20,530 layer again how thick is this ice layer 183 00:08:25,860 --> 00:08:23,590 we're not sure so it shows there is at 184 00:08:28,200 --> 00:08:25,870 least motion in the ice on your rope up 185 00:08:31,620 --> 00:08:28,210 and there's water deep underneath and 186 00:08:34,860 --> 00:08:31,630 the question is well how much that water 187 00:08:37,339 --> 00:08:34,870 gets up near the surface because if we 188 00:08:40,100 --> 00:08:37,349 want to check for life in the universe 189 00:08:43,260 --> 00:08:40,110 we need three things we need energy 190 00:08:46,260 --> 00:08:43,270 carbon and water that's what that's what 191 00:08:49,170 --> 00:08:46,270 life as we know it requires well energy 192 00:08:52,050 --> 00:08:49,180 and carbon are pretty easy to find water 193 00:08:53,490 --> 00:08:52,060 is really really hard to find so you 194 00:08:54,390 --> 00:08:53,500 rope out where we know there is some 195 00:08:56,910 --> 00:08:54,400 water 196 00:08:59,640 --> 00:08:56,920 is a place to look to see if life could 197 00:09:05,340 --> 00:08:59,650 have developed even microbial life on 198 00:09:07,980 --> 00:09:05,350 Europa alright so we have actually seen 199 00:09:08,940 --> 00:09:07,990 water plumes on another moon this is 200 00:09:10,320 --> 00:09:08,950 Saturn's moons 201 00:09:12,690 --> 00:09:10,330 Enceladus by the way this is Saturn's 202 00:09:13,860 --> 00:09:12,700 rings up here okay a nice edge on view 203 00:09:15,750 --> 00:09:13,870 of the Rings and this is from the 204 00:09:18,660 --> 00:09:15,760 Cassini satellite where you can see 205 00:09:23,430 --> 00:09:18,670 these plumes coming from Saturn's moon 206 00:09:26,850 --> 00:09:23,440 Enceladus alright and we've also seen 207 00:09:31,230 --> 00:09:26,860 indications of possible plumes on Europa 208 00:09:34,050 --> 00:09:31,240 from Hubble now Hubble did not see water 209 00:09:37,980 --> 00:09:34,060 plumes this was in 2012 what Hubble 210 00:09:41,040 --> 00:09:37,990 instead saw was auroral emissions from 211 00:09:45,420 --> 00:09:41,050 hydrogen and oxygen what is water 212 00:09:48,300 --> 00:09:45,430 composed of h2o hydrogen and oxygen so 213 00:09:51,180 --> 00:09:48,310 these are a rural emissions associated 214 00:09:53,880 --> 00:09:51,190 with Europa from hydrogen and oxygen 215 00:09:57,150 --> 00:09:53,890 which are indicative that there might be 216 00:09:59,550 --> 00:09:57,160 water plumes so how are we going to look 217 00:10:02,180 --> 00:09:59,560 for them well we're going to be tricky 218 00:10:06,150 --> 00:10:02,190 and we're going to look for them as 219 00:10:09,120 --> 00:10:06,160 Europa goes into transit in front of 220 00:10:12,660 --> 00:10:09,130 Jupiter that way we get the bright 221 00:10:17,310 --> 00:10:12,670 background of Jupiter in order to back 222 00:10:20,880 --> 00:10:17,320 illuminate Europa in order to search for 223 00:10:23,340 --> 00:10:20,890 these plumes so here are the actual 224 00:10:26,640 --> 00:10:23,350 images from the scientific paper as 225 00:10:28,190 --> 00:10:26,650 submitted all right so this background 226 00:10:34,200 --> 00:10:28,200 here is Jupiter 227 00:10:37,010 --> 00:10:34,210 this is Europa and here are some 228 00:10:39,990 --> 00:10:37,020 evidence of plumes here's another image 229 00:10:43,710 --> 00:10:40,000 again here is Europa here's some 230 00:10:46,500 --> 00:10:43,720 evidence of plumes as I said they're not 231 00:10:49,650 --> 00:10:46,510 pretty to look at but they indicate a 232 00:10:53,520 --> 00:10:49,660 really interesting story that there 233 00:10:57,210 --> 00:10:53,530 might be water plumes spewing out of 234 00:10:59,790 --> 00:10:57,220 Europa and we can then examine that 235 00:11:00,540 --> 00:10:59,800 water to see what is going on what is 236 00:11:02,700 --> 00:11:00,550 the chemistry 237 00:11:06,090 --> 00:11:02,710 what is the details of what may be going 238 00:11:07,519 --> 00:11:06,100 on and this internal ocean which if it's 239 00:11:09,650 --> 00:11:07,529 a hundred kilometers deep 240 00:11:12,679 --> 00:11:09,660 but below a below 100 kilometers of ice 241 00:11:14,629 --> 00:11:12,689 it's gonna be really hard to get down to 242 00:11:16,189 --> 00:11:14,639 okay you want to drill down 100 243 00:11:17,059 --> 00:11:16,199 kilometers to get to get to look at 244 00:11:19,579 --> 00:11:17,069 water ocean 245 00:11:21,410 --> 00:11:19,589 that's quite an engineering challenge if 246 00:11:23,449 --> 00:11:21,420 it's ten kilometres well I think that's 247 00:11:24,139 --> 00:11:23,459 a little bit easier it's still quite the 248 00:11:26,629 --> 00:11:24,149 challenge 249 00:11:29,629 --> 00:11:26,639 if however that water that water vapour 250 00:11:32,780 --> 00:11:29,639 is spewed out from the surface that's 251 00:11:34,939 --> 00:11:32,790 much much easier so this is an exciting 252 00:11:36,889 --> 00:11:34,949 announcement it is not absolutely a 253 00:11:42,290 --> 00:11:36,899 hundred percent confirmed that it is 254 00:11:44,239 --> 00:11:42,300 water plumes there all right but it does 255 00:11:46,489 --> 00:11:44,249 look like that there are water plumes 256 00:11:49,489 --> 00:11:46,499 coming from Europa and we will continue 257 00:11:52,579 --> 00:11:49,499 to study and have more information as we 258 00:11:54,860 --> 00:11:52,589 go this is an exciting idea of where 259 00:11:59,170 --> 00:11:54,870 we're going to look for potential life 260 00:12:02,660 --> 00:11:59,180 in our solar system our second story a 261 00:12:05,139 --> 00:12:02,670 smashing finale if you were here last 262 00:12:08,720 --> 00:12:05,149 month I talked about the Rosetta mission 263 00:12:10,189 --> 00:12:08,730 and the feel a lander that is in orbit 264 00:12:14,119 --> 00:12:10,199 around the comet 67p 265 00:12:16,759 --> 00:12:14,129 churyumov-gerasimenko all right yeah 266 00:12:19,749 --> 00:12:16,769 that's quite a mouthful to say and 267 00:12:23,720 --> 00:12:19,759 Rosetta is a mission that started in 268 00:12:26,869 --> 00:12:23,730 2004 it's been going for 12 years okay 269 00:12:29,509 --> 00:12:26,879 most of that time was spent in a very 270 00:12:32,269 --> 00:12:29,519 circuitous bunch of orbits just to get 271 00:12:34,519 --> 00:12:32,279 out to match orbits with the comet 272 00:12:37,129 --> 00:12:34,529 matter of fact it did a whole bunch of 273 00:12:41,509 --> 00:12:37,139 flybys in that process so it launched in 274 00:12:45,110 --> 00:12:41,519 March of 2004 it flew by earth in 2005 275 00:12:48,619 --> 00:12:45,120 Mars in 2007 earth in late 2007 the 276 00:12:53,629 --> 00:12:48,629 asteroid Stein's in 2008 earth again in 277 00:12:55,850 --> 00:12:53,639 2009 the asteroid leticia in July 2010 278 00:13:00,499 --> 00:12:55,860 and then spent four years matching 279 00:13:04,879 --> 00:13:00,509 orbits with comet 67p CG when it got 280 00:13:07,280 --> 00:13:04,889 there it found it was a contact binary 281 00:13:09,799 --> 00:13:07,290 comet which of course earned it the 282 00:13:16,040 --> 00:13:09,809 nickname comet rubber ducky for obvious 283 00:13:19,369 --> 00:13:16,050 reasons it has then since then and since 284 00:13:21,230 --> 00:13:19,379 its arrival in August 2014 the feel a 285 00:13:24,800 --> 00:13:21,240 lander was dropped down on 286 00:13:27,170 --> 00:13:24,810 November 2014 it stayed with the comet 287 00:13:29,449 --> 00:13:27,180 through its perihelion passage its 288 00:13:31,190 --> 00:13:29,459 closes passage by the Sun which is 289 00:13:33,889 --> 00:13:31,200 generally the most active time for a 290 00:13:35,690 --> 00:13:33,899 comet alright as it goes by the Sun most 291 00:13:37,130 --> 00:13:35,700 activities is going on there and it 292 00:13:40,430 --> 00:13:37,140 stayed with it for another year later 293 00:13:44,570 --> 00:13:40,440 and the mission ended last Friday 294 00:13:51,740 --> 00:13:44,580 September 30th 2016 with a very slow 295 00:13:55,940 --> 00:13:51,750 crash landing on 67p CG now you may 296 00:13:58,370 --> 00:13:55,950 remember that feel a landing was quite 297 00:14:01,970 --> 00:13:58,380 an event it was the only scientific 298 00:14:07,130 --> 00:14:01,980 event I know of that had a live blog by 299 00:14:09,949 --> 00:14:07,140 a webcomic xkcd the author of xkcd drew 300 00:14:12,920 --> 00:14:09,959 over a hundred different pictures to 301 00:14:15,350 --> 00:14:12,930 live blog the landing of feel a over the 302 00:14:16,760 --> 00:14:15,360 course of several hours as it was going 303 00:14:19,130 --> 00:14:16,770 so you can see here's the one I chose 304 00:14:22,250 --> 00:14:19,140 from time into landing three hours and 305 00:14:24,680 --> 00:14:22,260 he has all sorts of fun information and 306 00:14:25,340 --> 00:14:24,690 makes a make some make some good science 307 00:14:28,310 --> 00:14:25,350 jokes 308 00:14:31,370 --> 00:14:28,320 if you don't know xkcd it's a very very 309 00:14:32,780 --> 00:14:31,380 geek comic okay so if you want to grow 310 00:14:37,690 --> 00:14:32,790 up to be geeks guys in the front row 311 00:14:44,720 --> 00:14:41,990 the feel a lander however didn't happen 312 00:14:47,240 --> 00:14:44,730 the way it actually bounced the the the 313 00:14:48,800 --> 00:14:47,250 rockets that were were gonna the anchors 314 00:14:51,949 --> 00:14:48,810 that were gonna push into the comet 315 00:14:54,590 --> 00:14:51,959 didn't quite quite work and it was lost 316 00:14:57,560 --> 00:14:54,600 until as I showed you last month it was 317 00:15:00,170 --> 00:14:57,570 found in this little crag here the feel 318 00:15:02,870 --> 00:15:00,180 a lander was finally discovered as the 319 00:15:05,449 --> 00:15:02,880 Rosetta orbiter got close in enough to 320 00:15:07,970 --> 00:15:05,459 actually see in search for it and found 321 00:15:11,780 --> 00:15:07,980 it so there's the last resting place of 322 00:15:14,050 --> 00:15:11,790 feel a of course the Rosetta orbiter 323 00:15:18,800 --> 00:15:14,060 itself 324 00:15:21,110 --> 00:15:18,810 joined it last Friday but what if I 325 00:15:23,150 --> 00:15:21,120 remember this most about this mission is 326 00:15:23,870 --> 00:15:23,160 not going to be these images I'm going 327 00:15:27,519 --> 00:15:23,880 to show you in a minute 328 00:15:31,250 --> 00:15:27,529 but really the number of really cool 329 00:15:34,130 --> 00:15:31,260 outburst images that Rosetta was able to 330 00:15:34,639 --> 00:15:34,140 get because it stayed with the comet for 331 00:15:40,100 --> 00:15:34,649 a year 332 00:15:42,079 --> 00:15:40,110 perihelion covering this active time in 333 00:15:44,269 --> 00:15:42,089 a life of the comet you can see all of 334 00:15:46,939 --> 00:15:44,279 these outbursts it was able to capture 335 00:15:49,639 --> 00:15:46,949 this is an immense data set that we will 336 00:15:50,629 --> 00:15:49,649 look at for years and and and even 337 00:15:53,660 --> 00:15:50,639 decades to come 338 00:15:55,910 --> 00:15:53,670 yes that was in The Wall Street The Wall 339 00:15:57,470 --> 00:15:55,920 Street Journal covered the the outburst 340 00:16:03,619 --> 00:15:57,480 because this is one of the great montage 341 00:16:06,309 --> 00:16:03,629 images well I'm glad to hear the Wall 342 00:16:09,710 --> 00:16:06,319 Street Journal Street Journal covers 343 00:16:13,819 --> 00:16:09,720 great science because this is an amazing 344 00:16:15,530 --> 00:16:13,829 amount of just amazing amount of 345 00:16:18,379 --> 00:16:15,540 observations compared to what we've had 346 00:16:20,239 --> 00:16:18,389 in terms of covering outbursts on comets 347 00:16:23,540 --> 00:16:20,249 okay and this this data set will be 348 00:16:26,179 --> 00:16:23,550 mined for years to come okay so they 349 00:16:29,299 --> 00:16:26,189 took 15 image they released 15 images of 350 00:16:31,460 --> 00:16:29,309 the descent of Rosetta over the last 24 351 00:16:33,679 --> 00:16:31,470 hours so in the lower-left this is the 352 00:16:35,840 --> 00:16:33,689 time to impact 23 hours 30 minutes for 353 00:16:38,030 --> 00:16:35,850 this first image and here's the height 354 00:16:41,840 --> 00:16:38,040 above the center of the comet 22.9 355 00:16:44,840 --> 00:16:43,280 and this is just a counting number so I 356 00:16:46,910 --> 00:16:44,850 can keep track 357 00:16:48,710 --> 00:16:46,920 downloading 15 images and keeping them 358 00:16:50,869 --> 00:16:48,720 the correct orders never caught in there 359 00:16:53,449 --> 00:16:50,879 oh it's not that easy alright so here 360 00:16:55,489 --> 00:16:53,459 you can see that a day before it's still 361 00:16:58,280 --> 00:16:55,499 you know you're seeing pretty much the 362 00:16:59,780 --> 00:16:58,290 comment you've got a you know a full 363 00:17:01,189 --> 00:16:59,790 sized view of the comment and you can 364 00:17:03,259 --> 00:17:01,199 see it's orbiting around the comet in 365 00:17:06,620 --> 00:17:03,269 the comet itself is turning the comet 366 00:17:08,480 --> 00:17:06,630 nucleus and as we start to get in now 367 00:17:11,630 --> 00:17:08,490 we're down just a little bit closer at 368 00:17:13,490 --> 00:17:11,640 20 kilometers and also these images go 369 00:17:15,860 --> 00:17:13,500 from the wide-angle view to the narrow 370 00:17:17,299 --> 00:17:15,870 angle view here you've got and start to 371 00:17:19,010 --> 00:17:17,309 see that you can see they're very craggy 372 00:17:23,179 --> 00:17:19,020 surface almost feels like it's sharp 373 00:17:26,120 --> 00:17:23,189 okay surface moving in you can see the 374 00:17:28,639 --> 00:17:26,130 sort of steps across there really 375 00:17:30,169 --> 00:17:28,649 interesting structures and then you've 376 00:17:32,210 --> 00:17:30,179 got a series of couple images where you 377 00:17:35,180 --> 00:17:32,220 can see this the same structures these 378 00:17:37,370 --> 00:17:35,190 are just relatively close in time you 379 00:17:40,519 --> 00:17:37,380 can see that structure here and you can 380 00:17:43,669 --> 00:17:40,529 see the structures it was moving through 381 00:17:45,649 --> 00:17:43,679 here then we get the what I think is the 382 00:17:46,980 --> 00:17:45,659 coolest image so we've been looking down 383 00:17:50,820 --> 00:17:46,990 on this 384 00:17:52,110 --> 00:17:50,830 then we get this image which looks like 385 00:17:54,960 --> 00:17:52,120 you're down on the surface of the comet 386 00:17:57,510 --> 00:17:54,970 right but what it has to be because 387 00:17:59,850 --> 00:17:57,520 you're 16 kilometers away from the comet 388 00:18:02,220 --> 00:17:59,860 this is the narrow angle camera right 389 00:18:04,200 --> 00:18:02,230 but what it has to be is whoops let me 390 00:18:07,320 --> 00:18:04,210 go back is that you're looking at one of 391 00:18:09,210 --> 00:18:07,330 these crags here from the side okay so 392 00:18:11,820 --> 00:18:09,220 as it orbits around the comet it's 393 00:18:14,370 --> 00:18:11,830 looking directly along here and you're 394 00:18:16,440 --> 00:18:14,380 looking in to see these crags sticking 395 00:18:18,419 --> 00:18:16,450 up and I actually think this is the 396 00:18:21,390 --> 00:18:18,429 coolest image of all of all the series 397 00:18:23,730 --> 00:18:21,400 of 15 because it just sort of gets you a 398 00:18:25,200 --> 00:18:23,740 feeling like you are there if you don't 399 00:18:28,590 --> 00:18:25,210 almost feel like you're walking on on 400 00:18:30,090 --> 00:18:28,600 the surface of the comet nucleus so this 401 00:18:35,490 --> 00:18:30,100 is kind of fun it looks a little bit 402 00:18:40,530 --> 00:18:35,500 like what's the there's a national park 403 00:18:42,270 --> 00:18:40,540 in the southwest Bryce Canyon that's it 404 00:18:44,130 --> 00:18:42,280 Bryce Canyon has a little bit of the 405 00:18:48,840 --> 00:18:44,140 hoodoo feel of Bryce Canyon National 406 00:18:50,340 --> 00:18:48,850 Park but Bryce Canyon doesn't it doesn't 407 00:18:55,070 --> 00:18:50,350 look that that rocky and in that case 408 00:18:57,180 --> 00:18:55,080 anyways so there is no erosion right 409 00:18:59,220 --> 00:18:57,190 exactly it couldn't be 410 00:19:00,810 --> 00:18:59,230 you couldn't have real hoodoos here 411 00:19:03,799 --> 00:19:00,820 because you wouldn't because dollars are 412 00:19:06,600 --> 00:19:03,809 produced by water erosion creating them 413 00:19:08,100 --> 00:19:06,610 this is I'm not an expert on the on this 414 00:19:09,000 --> 00:19:08,110 okay matter of fact I'll show you how 415 00:19:10,440 --> 00:19:09,010 much I'm an honor an expert because 416 00:19:12,600 --> 00:19:10,450 they've got a couple images here that 417 00:19:14,790 --> 00:19:12,610 I'm not exactly sure why they look like 418 00:19:16,590 --> 00:19:14,800 this either okay 419 00:19:18,650 --> 00:19:16,600 and then you can see as we're getting 420 00:19:22,169 --> 00:19:18,660 closer we're nine hours before impact 421 00:19:23,970 --> 00:19:22,179 okay and then we jump to almost six 422 00:19:25,950 --> 00:19:23,980 hours for impact and here you can again 423 00:19:28,080 --> 00:19:25,960 see these sort of striations structures 424 00:19:29,820 --> 00:19:28,090 okay which to me look like sedimentary 425 00:19:31,890 --> 00:19:29,830 stuff and I know it's not sedimentary 426 00:19:34,110 --> 00:19:31,900 stuff maybe it's produced by the 427 00:19:37,680 --> 00:19:34,120 collision of those to contact binary 428 00:19:39,270 --> 00:19:37,690 objects that form the contact binary so 429 00:19:41,360 --> 00:19:39,280 you've got this sort of striated stuff 430 00:19:45,150 --> 00:19:41,370 and then you get this sort of leather 431 00:19:47,040 --> 00:19:45,160 leathery type plane here okay and we 432 00:19:48,750 --> 00:19:47,050 have a lot of this type of plane that 433 00:19:53,280 --> 00:19:48,760 that we zooming in we're down 3 hours 434 00:19:56,070 --> 00:19:53,290 before impact ok moving in here here is 435 00:19:58,260 --> 00:19:56,080 the target area for where they're going 436 00:20:00,480 --> 00:19:58,270 to land it you can see that cliff along 437 00:20:03,270 --> 00:20:00,490 here three hours before impact 438 00:20:05,430 --> 00:20:03,280 six kilometers about the surface down to 439 00:20:07,650 --> 00:20:05,440 one point two kilometers you can see an 440 00:20:09,450 --> 00:20:07,660 edge with this very sharp sharp shadow 441 00:20:12,840 --> 00:20:09,460 here all right you're seeing the details 442 00:20:15,840 --> 00:20:12,850 and then the final image one minute 443 00:20:18,450 --> 00:20:15,850 before impact this is from 20 meters 444 00:20:22,320 --> 00:20:18,460 height I'm told this is about one meter 445 00:20:24,330 --> 00:20:22,330 across on the comet so it's out of focus 446 00:20:28,320 --> 00:20:24,340 because the cameras were never meant to 447 00:20:31,620 --> 00:20:28,330 focus 20 meters away from it and then 448 00:20:35,280 --> 00:20:31,630 boom the res that a signal was lost 449 00:20:40,230 --> 00:20:35,290 11:19 GMT here is the signal and there 450 00:20:43,730 --> 00:20:40,240 is not okay so the Rosetta mission will 451 00:20:46,560 --> 00:20:43,740 live on through it's amazing data set 452 00:20:49,920 --> 00:20:46,570 when I tweeted about this I said Rosetta 453 00:20:55,110 --> 00:20:49,930 is dead long live Rosetta because it 454 00:20:58,140 --> 00:20:55,120 really will have an amazing impact on 455 00:21:01,260 --> 00:20:58,150 cometary science however it will not 456 00:21:03,450 --> 00:21:01,270 have the kind of impact that people talk 457 00:21:07,080 --> 00:21:03,460 about in Hollywood movies so I'm gonna 458 00:21:09,750 --> 00:21:07,090 give the last word to xkcd who put out a 459 00:21:10,850 --> 00:21:09,760 Rosetta comic on Friday you can read it 460 00:21:13,890 --> 00:21:10,860 for yourself 461 00:21:16,920 --> 00:21:13,900 and it references the movie Armageddon 462 00:21:20,010 --> 00:21:16,930 in which they did try to blow up a 463 00:21:21,930 --> 00:21:20,020 comment to deflect it this was not meant 464 00:21:26,270 --> 00:21:21,940 to deflect the comet Bruce Willis was 465 00:21:36,780 --> 00:21:26,280 not required on the Rosetta mission okay 466 00:21:40,620 --> 00:21:36,790 any questions for yes okay so as the 467 00:21:42,990 --> 00:21:40,630 comet approaches the Sun it heats up and 468 00:21:47,910 --> 00:21:43,000 any pockets of volatiles that are near 469 00:21:48,480 --> 00:21:47,920 the surface can can it can can go from 470 00:21:51,750 --> 00:21:48,490 there 471 00:21:54,030 --> 00:21:51,760 isis state to gaseous state and blow out 472 00:21:55,980 --> 00:21:54,040 as Jets that's very common on comets 473 00:21:59,460 --> 00:21:55,990 matter of fact the what you're looking 474 00:22:01,860 --> 00:21:59,470 at with the 67p CG mostly is the comet 475 00:22:04,050 --> 00:22:01,870 nucleus okay but what you usually think 476 00:22:06,510 --> 00:22:04,060 of the knew of a comet is this big fuzzy 477 00:22:08,790 --> 00:22:06,520 ball well that's the coma that's all the 478 00:22:11,040 --> 00:22:08,800 gases that have have come out from the 479 00:22:14,049 --> 00:22:11,050 comet all right and then you get that 480 00:22:15,729 --> 00:22:14,059 those gases get swept back into a tail 481 00:22:18,249 --> 00:22:15,739 and that's what produces your standard 482 00:22:21,399 --> 00:22:18,259 idea of a comment what we're studying 483 00:22:24,190 --> 00:22:21,409 here is really the comet nucleus and 484 00:22:26,649 --> 00:22:24,200 those outbursts are the gases that are 485 00:22:30,519 --> 00:22:26,659 that are bursting out it the perihelion 486 00:22:32,979 --> 00:22:30,529 for 67p is only one point two times the 487 00:22:34,739 --> 00:22:32,989 Earth's distance to the Sun so it never 488 00:22:38,200 --> 00:22:34,749 gets really really close to the Sun 489 00:22:40,180 --> 00:22:38,210 therefore it doesn't doesn't burst out 490 00:22:42,009 --> 00:22:40,190 that much and it doesn't produce a coma 491 00:22:45,190 --> 00:22:42,019 it's a short period comet only has a six 492 00:22:47,320 --> 00:22:45,200 point four year period so it doesn't 493 00:22:50,739 --> 00:22:47,330 develop a big long tail like you may 494 00:22:53,079 --> 00:22:50,749 have seen with comet hale-bopp or the 495 00:22:54,759 --> 00:22:53,089 way we depict comet West or comet 496 00:22:57,669 --> 00:22:54,769 aquellas ecchi or other of these 497 00:22:59,469 --> 00:22:57,679 spectacular comets this is just your 498 00:23:00,039 --> 00:22:59,479 normal ordinary run-of-the-mill boring 499 00:23:04,749 --> 00:23:00,049 comet 500 00:23:07,419 --> 00:23:04,759 boring they are that ice ball nucleus 501 00:23:09,489 --> 00:23:07,429 with the Jets coming out and not these 502 00:23:11,680 --> 00:23:09,499 big huge tails that last that stretch 503 00:23:17,769 --> 00:23:11,690 for millions of kilometres good question 504 00:23:19,869 --> 00:23:17,779 thank you yes it's ice and rock it's ice 505 00:23:21,700 --> 00:23:19,879 and rock I usually usually think of them 506 00:23:34,180 --> 00:23:21,710 as ice balls but we know if we actually 507 00:23:38,259 --> 00:23:34,190 know yes they are ice and rock yes it 508 00:23:40,719 --> 00:23:38,269 could be I say it does look a lot like 509 00:23:42,909 --> 00:23:40,729 rocks scatter and you will expose my 510 00:23:45,690 --> 00:23:42,919 ignorance on the commentary services 511 00:23:48,459 --> 00:23:45,700 we've never seen commentary surfaces and 512 00:23:51,669 --> 00:23:48,469 that incredible detail we actually you 513 00:23:53,169 --> 00:23:51,679 know with Pluto last year and the the 514 00:23:55,629 --> 00:23:53,179 Deep Impact mission that we did a few 515 00:23:57,519 --> 00:23:55,639 years ago and this we're learning so 516 00:23:59,529 --> 00:23:57,529 much and actually what we're seeing on 517 00:24:02,950 --> 00:23:59,539 Europa as well we're learning so much 518 00:24:05,079 --> 00:24:02,960 about Isis and how they behave out in 519 00:24:06,310 --> 00:24:05,089 the solar system we're just seeing you 520 00:24:10,169 --> 00:24:06,320 know cryovolcanism 521 00:24:15,639 --> 00:24:10,179 on on Pluto the kraaho tectonics on 522 00:24:17,589 --> 00:24:15,649 Europa and so how these ices interact is 523 00:24:20,109 --> 00:24:17,599 something that that's actually pretty 524 00:24:21,249 --> 00:24:20,119 new and I think it's a quite an 525 00:24:22,109 --> 00:24:21,259 interesting field that has developed 526 00:24:25,719 --> 00:24:22,119 lately 527 00:24:27,129 --> 00:24:25,729 alright I well I have to I have to get 528 00:24:27,930 --> 00:24:27,139 to Bill's talk otherwise we'll be here 529 00:24:30,360 --> 00:24:27,940 wait 530 00:24:33,450 --> 00:24:30,370 late alright so let me go to our 531 00:24:35,999 --> 00:24:33,460 featured speaker and our featured 532 00:24:39,060 --> 00:24:36,009 speaker tonight is Bill Blair from the 533 00:24:40,889 --> 00:24:39,070 Johns Hopkins University and it is Johns 534 00:24:44,039 --> 00:24:40,899 Hopkins make sure everybody in Baltimore 535 00:24:47,009 --> 00:24:44,049 knows that okay bill has been there and 536 00:24:48,930 --> 00:24:47,019 he told me since 1984 and I was like he 537 00:24:50,869 --> 00:24:48,940 doesn't look old enough to have been 538 00:24:57,810 --> 00:24:50,879 around since my teenager 539 00:25:00,570 --> 00:24:57,820 yes he got his PhD at 12 he has worked 540 00:25:02,909 --> 00:25:00,580 on several major instruments the Hopkins 541 00:25:05,100 --> 00:25:02,919 ultraviolet telescope that flew on the 542 00:25:06,659 --> 00:25:05,110 Space Shuttle twice we had hoped it 543 00:25:09,240 --> 00:25:06,669 would fly a few more times on the space 544 00:25:12,240 --> 00:25:09,250 shuttle and then he moved over to the 545 00:25:15,990 --> 00:25:12,250 Far all Tobias copic Explorer also 546 00:25:19,259 --> 00:25:16,000 called fuse working in as you can see in 547 00:25:21,779 --> 00:25:19,269 ultraviolet and now he has moved to 548 00:25:24,480 --> 00:25:21,789 infrared he most of his time is spent 549 00:25:29,100 --> 00:25:24,490 now on the James Webb Space Telescope 550 00:25:30,389 --> 00:25:29,110 and I don't know what else to say it 551 00:25:33,060 --> 00:25:30,399 he's a really great guy I think you're 552 00:25:39,090 --> 00:25:33,070 gonna enjoy his talk tonight ladies and 553 00:25:45,400 --> 00:25:42,010 thank you very much it's a great 554 00:25:46,990 --> 00:25:45,410 pleasure to be here tonight to tell you 555 00:25:49,510 --> 00:25:47,000 about some research that I've been 556 00:25:51,010 --> 00:25:49,520 involved with most of my effort these 557 00:25:53,350 --> 00:25:51,020 days is functional work I'm actually 558 00:25:55,660 --> 00:25:53,360 working to help the Institute prepare 559 00:25:58,090 --> 00:25:55,670 for the James Webb telescope and prepare 560 00:25:59,920 --> 00:25:58,100 the the ground system is called the 561 00:26:02,050 --> 00:25:59,930 software and the systems that will 562 00:26:04,510 --> 00:26:02,060 support the James Webb telescope and 563 00:26:07,540 --> 00:26:04,520 astronomers - proposed for the James 564 00:26:09,520 --> 00:26:07,550 Webb telescope and so most of my effort 565 00:26:11,380 --> 00:26:09,530 is in meetings and that kind of stuff 566 00:26:13,150 --> 00:26:11,390 now but I do have a bunch of good 567 00:26:15,790 --> 00:26:13,160 collaborators and and over the last six 568 00:26:17,680 --> 00:26:15,800 or seven years we're partway through a 569 00:26:19,300 --> 00:26:17,690 research project that I'll eventually 570 00:26:20,800 --> 00:26:19,310 get to tonight I want to tell you some 571 00:26:23,860 --> 00:26:20,810 other things first before we get there 572 00:26:26,110 --> 00:26:23,870 on this galaxy m83 and in the background 573 00:26:29,620 --> 00:26:26,120 here you see what is a large mosaic 574 00:26:31,030 --> 00:26:29,630 image from the Hubble telescope some of 575 00:26:34,570 --> 00:26:31,040 the one the datasets that we took for 576 00:26:36,910 --> 00:26:34,580 this project to help us look for look at 577 00:26:38,830 --> 00:26:36,920 the star formation great huge amounts of 578 00:26:41,260 --> 00:26:38,840 star formation huge amounts of star 579 00:26:43,510 --> 00:26:41,270 formation going on in here and and then 580 00:26:45,520 --> 00:26:43,520 find the supernova remnants which is the 581 00:26:47,440 --> 00:26:45,530 stellar life the birth and evolution of 582 00:26:48,010 --> 00:26:47,450 stars and then the stellar gases the 583 00:26:50,920 --> 00:26:48,020 backend 584 00:26:52,060 --> 00:26:50,930 the supernova supernovae and the 585 00:26:55,720 --> 00:26:52,070 remnants the things that they leave 586 00:26:58,120 --> 00:26:55,730 behind and we try to study that galaxy 587 00:27:00,250 --> 00:26:58,130 and put it in context with our own Milky 588 00:27:04,440 --> 00:27:00,260 Way galaxy and other galaxies here in 589 00:27:08,800 --> 00:27:04,450 our local group for instance okay so 590 00:27:10,630 --> 00:27:08,810 before get to the the the meat of things 591 00:27:12,940 --> 00:27:10,640 here with the star formation and 592 00:27:15,040 --> 00:27:12,950 supernova remnants I want to spend a 593 00:27:18,040 --> 00:27:15,050 couple minutes giving you some context 594 00:27:19,710 --> 00:27:18,050 and tell you about how we find the 595 00:27:22,660 --> 00:27:19,720 supernova remnants in other galaxies 596 00:27:24,040 --> 00:27:22,670 we'll talk about what we see locally and 597 00:27:27,970 --> 00:27:24,050 what we're trying to find as we look 598 00:27:30,280 --> 00:27:27,980 farther away and then we'll get into m83 599 00:27:35,680 --> 00:27:30,290 itself and what we are finding and some 600 00:27:38,440 --> 00:27:35,690 ideas of of what it might might mean so 601 00:27:40,090 --> 00:27:38,450 part of the context I like to do I like 602 00:27:42,910 --> 00:27:40,100 to try to do a few things to make big 603 00:27:44,590 --> 00:27:42,920 numbers understandable you know we hear 604 00:27:46,150 --> 00:27:44,600 so much you know in the public domain 605 00:27:48,160 --> 00:27:46,160 these days we hear millions and billions 606 00:27:49,540 --> 00:27:48,170 and trillions thrown around and they're 607 00:27:51,640 --> 00:27:49,550 just big numbers we just don't 608 00:27:53,710 --> 00:27:51,650 understand how big number 609 00:27:55,210 --> 00:27:53,720 really are and in astronomy of course we 610 00:27:57,850 --> 00:27:55,220 have to deal with a lot of big numbers 611 00:28:00,460 --> 00:27:57,860 we have the problem of distances I mean 612 00:28:03,040 --> 00:28:00,470 one light-year our yardstick that we use 613 00:28:05,890 --> 00:28:03,050 in in astronomy is some six trillion 614 00:28:09,160 --> 00:28:05,900 miles six times ten to the twelfth a six 615 00:28:11,620 --> 00:28:09,170 with 12 zeros miles in one light year 616 00:28:14,170 --> 00:28:11,630 and the nearest star is 4.3 light years 617 00:28:16,710 --> 00:28:14,180 away but the distances to quasars and 618 00:28:19,060 --> 00:28:16,720 galaxies are millions or billions of 619 00:28:21,250 --> 00:28:19,070 light-years and so these are just big 620 00:28:23,500 --> 00:28:21,260 numbers they kind of lose their context 621 00:28:25,420 --> 00:28:23,510 the same thing with discussion in the 622 00:28:27,700 --> 00:28:25,430 public domain when we talk about budgets 623 00:28:29,170 --> 00:28:27,710 and and this kind of thing and I think 624 00:28:31,210 --> 00:28:29,180 part of the problem is you know we kind 625 00:28:32,680 --> 00:28:31,220 of here million billion trillion and we 626 00:28:34,720 --> 00:28:32,690 think they're kind of factors of 10 627 00:28:37,180 --> 00:28:34,730 apart but they're not they're factors of 628 00:28:39,370 --> 00:28:37,190 a thousand apart you know it's a 629 00:28:42,520 --> 00:28:39,380 thousand millions make a billion and a 630 00:28:44,920 --> 00:28:42,530 thousand billions to make a trillion 631 00:28:47,530 --> 00:28:44,930 okay so I thought I would just do a 632 00:28:51,820 --> 00:28:47,540 little exercise to give you some idea of 633 00:28:55,450 --> 00:28:51,830 how big a billion is okay so I have some 634 00:28:56,770 --> 00:28:55,460 props here I have a ream of paper I want 635 00:28:59,170 --> 00:28:56,780 you to use your imagination here a 636 00:29:00,880 --> 00:28:59,180 little bit okay so Rina Rina paper has 637 00:29:05,620 --> 00:29:00,890 how many how many sheets of paper in a 638 00:29:08,560 --> 00:29:05,630 ream you know 500 500 sheets okay let's 639 00:29:10,140 --> 00:29:08,570 assume every sheet of paper in here is a 640 00:29:15,250 --> 00:29:10,150 hundred dollar bill 641 00:29:19,360 --> 00:29:15,260 that's 50 thousand dollars right there 642 00:29:20,920 --> 00:29:19,370 okay so if I take two of those we got a 643 00:29:23,110 --> 00:29:20,930 hundred thousand dollars so that's a 644 00:29:26,260 --> 00:29:23,120 little easier to go by factors of 10 645 00:29:28,960 --> 00:29:26,270 from so there's two there's a hundred 646 00:29:32,650 --> 00:29:28,970 thousand dollars $100 bills side by side 647 00:29:35,140 --> 00:29:32,660 and I got a yardstick here that happens 648 00:29:40,090 --> 00:29:35,150 to be about four inches okay so four 649 00:29:43,630 --> 00:29:40,100 inches of paper is like $100,000 so ten 650 00:29:44,950 --> 00:29:43,640 times that is a million dollars okay if 651 00:29:47,830 --> 00:29:44,960 we had the stack of paper that high 652 00:29:50,200 --> 00:29:47,840 that's a meter stick 40 inches that 653 00:29:52,060 --> 00:29:50,210 would be a million dollars so $100 bills 654 00:29:55,660 --> 00:29:52,070 stacked up to there there's a million 655 00:30:00,720 --> 00:29:55,670 dollars a billion dollars is a thousand 656 00:30:02,529 --> 00:30:00,730 times that a kilometer 6/10 of a mile 657 00:30:04,629 --> 00:30:02,539 okay 658 00:30:06,099 --> 00:30:04,639 so when you're here so you still I could 659 00:30:08,739 --> 00:30:06,109 pick a random number out of the you know 660 00:30:13,060 --> 00:30:08,749 the the news you know nine hundred 661 00:30:15,699 --> 00:30:13,070 thirteen million that's over half a mile 662 00:30:17,019 --> 00:30:15,709 high stack of $100 bills folks so that's 663 00:30:19,659 --> 00:30:17,029 that's a big number 664 00:30:21,699 --> 00:30:19,669 okay big numbers that so let's do one 665 00:30:23,589 --> 00:30:21,709 more thing let's go one more step look 666 00:30:25,329 --> 00:30:23,599 instead of money let's talk about time 667 00:30:27,819 --> 00:30:25,339 because time is another thing in 668 00:30:29,859 --> 00:30:27,829 astronomy that gets pretty pretty hairy 669 00:30:31,989 --> 00:30:29,869 for us and it's because there's such a 670 00:30:33,579 --> 00:30:31,999 dichotomy between our experience of time 671 00:30:37,479 --> 00:30:33,589 we're like a hundred years is a long 672 00:30:40,359 --> 00:30:37,489 time to us but to realize that a million 673 00:30:42,759 --> 00:30:40,369 years or in some context even a billion 674 00:30:45,249 --> 00:30:42,769 years in astronomy is considered a short 675 00:30:48,369 --> 00:30:45,259 time because this universe itself is 676 00:30:50,979 --> 00:30:48,379 13.8 billion years and so you're looking 677 00:30:52,989 --> 00:30:50,989 at the evolution of galaxies from early 678 00:30:54,519 --> 00:30:52,999 times on you know a billion years is 679 00:30:57,069 --> 00:30:54,529 really not that long 680 00:30:58,749 --> 00:30:57,079 believe it or not right so we could do 681 00:31:00,939 --> 00:30:58,759 that same thing let's take one sheet of 682 00:31:03,059 --> 00:31:00,949 paper and this is now a time line okay 683 00:31:05,439 --> 00:31:03,069 one sheet of paper is a hundred years a 684 00:31:08,409 --> 00:31:05,449 like a human lifetime a long human 685 00:31:12,159 --> 00:31:08,419 lifetime okay well then a million years 686 00:31:16,719 --> 00:31:12,169 is that big and a billion years is the 687 00:31:20,169 --> 00:31:16,729 6/10 of a mile one kilometer tall so 688 00:31:22,629 --> 00:31:20,179 this is a short time in astronomy one 689 00:31:24,579 --> 00:31:22,639 sheet of paper is a long time to us and 690 00:31:27,069 --> 00:31:24,589 that's why we sometimes have a hard time 691 00:31:29,019 --> 00:31:27,079 communicating these big these big 692 00:31:32,589 --> 00:31:29,029 numbers well so now we're going to look 693 00:31:34,389 --> 00:31:32,599 at star formation in m83 you collapsed a 694 00:31:35,559 --> 00:31:34,399 cloud of gas and dust it creates a whole 695 00:31:38,919 --> 00:31:35,569 bunch of stars there are a whole range 696 00:31:41,489 --> 00:31:38,929 of different masses the big massive 697 00:31:43,839 --> 00:31:41,499 stars only live for a few million years 698 00:31:45,639 --> 00:31:43,849 short time ok 699 00:31:47,229 --> 00:31:45,649 whereas I mean our Sun we know is 700 00:31:48,729 --> 00:31:47,239 four-and-a-half billion years there's 701 00:31:51,489 --> 00:31:48,739 only maybe about halfway through its 702 00:31:53,919 --> 00:31:51,499 lifetime so the low mass stars that form 703 00:31:56,349 --> 00:31:53,929 will stay around almost almost forever 704 00:31:58,479 --> 00:31:56,359 from an evolutionary standpoint for the 705 00:32:00,129 --> 00:31:58,489 galaxies standpoint whereas it's the 706 00:32:03,939 --> 00:32:00,139 most massive stars the ones that live 707 00:32:06,249 --> 00:32:03,949 live live fast and die young that that 708 00:32:09,009 --> 00:32:06,259 create most of the energising of the 709 00:32:11,079 --> 00:32:09,019 interstellar gas forcing new star 710 00:32:13,209 --> 00:32:11,089 formation to happen as those shockwaves 711 00:32:14,859 --> 00:32:13,219 from the supernova impact clouds of gas 712 00:32:16,390 --> 00:32:14,869 and dust and make them collapse and so 713 00:32:18,310 --> 00:32:16,400 forth so I'll 714 00:32:21,280 --> 00:32:18,320 probably mostly concentrate on the more 715 00:32:23,080 --> 00:32:21,290 massive stars and supernova remnants 716 00:32:27,370 --> 00:32:23,090 that come from those masters stars as we 717 00:32:29,740 --> 00:32:27,380 go on through the talk the other piece 718 00:32:32,080 --> 00:32:29,750 of context I wanted to give you is we 719 00:32:33,640 --> 00:32:32,090 all love these beautiful color pictures 720 00:32:36,160 --> 00:32:33,650 that we get out of Hubble and out of 721 00:32:38,050 --> 00:32:36,170 other missions as well and I wanted to 722 00:32:40,420 --> 00:32:38,060 put that in context a little bit as well 723 00:32:42,580 --> 00:32:40,430 this is the Kepler supernova remnant it 724 00:32:46,000 --> 00:32:42,590 came from an explosion that Johannes 725 00:32:47,890 --> 00:32:46,010 Kepler observed in 1604 one of my 726 00:32:50,140 --> 00:32:47,900 favorite objects here and what we're 727 00:32:52,810 --> 00:32:50,150 looking at in this color picture is 728 00:32:55,210 --> 00:32:52,820 actually a combination of Chandra x-ray 729 00:32:57,340 --> 00:32:55,220 data two different colors here blue in 730 00:32:59,200 --> 00:32:57,350 the green in this picture this is harder 731 00:33:01,720 --> 00:32:59,210 x-rays that show you the kind of the 732 00:33:04,750 --> 00:33:01,730 outer rim is the brightest that's the 733 00:33:06,760 --> 00:33:04,760 shock wave and the hardest x-rays the 734 00:33:09,370 --> 00:33:06,770 green is a little bit interior to that 735 00:33:12,820 --> 00:33:09,380 that is the actual ejecta the star stuff 736 00:33:15,280 --> 00:33:12,830 from the supernova that exploded okay 737 00:33:17,260 --> 00:33:15,290 the yellow which I'll show in more 738 00:33:19,210 --> 00:33:17,270 detail on the other side here but you 739 00:33:20,980 --> 00:33:19,220 see the yellow in here is the densest 740 00:33:22,810 --> 00:33:20,990 clumps of stuff that's what Hubble sees 741 00:33:25,390 --> 00:33:22,820 is the really dead stuff in the optical 742 00:33:26,920 --> 00:33:25,400 so the yellow is Hubble and this is one 743 00:33:28,870 --> 00:33:26,930 wavelength of infrared emission from the 744 00:33:31,690 --> 00:33:28,880 Spitzer Space Telescope it's actually 745 00:33:33,580 --> 00:33:31,700 showing us warm dust that is heated by 746 00:33:35,800 --> 00:33:33,590 the shockwave and you see how it's 747 00:33:38,680 --> 00:33:35,810 one-sided how one side of this structure 748 00:33:41,680 --> 00:33:38,690 is really dominant in the heated dust 749 00:33:43,180 --> 00:33:41,690 and that's it turns out putting all this 750 00:33:45,490 --> 00:33:43,190 together like this is telling us that 751 00:33:47,530 --> 00:33:45,500 the shockwave was running up a density 752 00:33:50,410 --> 00:33:47,540 gradient it's denser up there in the 753 00:33:52,060 --> 00:33:50,420 upper right and the dust is denser and 754 00:33:55,170 --> 00:33:52,070 it's getting heated up by the shockwave 755 00:33:57,640 --> 00:33:55,180 is that impinges on that denser material 756 00:33:59,440 --> 00:33:57,650 so again looking at things at different 757 00:34:02,590 --> 00:33:59,450 wavelengths one of the points here is 758 00:34:05,500 --> 00:34:02,600 that supernova remnants observe across 759 00:34:07,330 --> 00:34:05,510 the light spectrum from x-ray all the 760 00:34:08,950 --> 00:34:07,340 way out to radio I don't have radio on 761 00:34:12,370 --> 00:34:08,960 here but they're strong radio sources as 762 00:34:14,590 --> 00:34:12,380 well infrared optical ultraviolet across 763 00:34:15,909 --> 00:34:14,600 the spectrum they're very multi 764 00:34:18,250 --> 00:34:15,919 wavelength and so that's right I'm 765 00:34:21,159 --> 00:34:18,260 taking a multi wavelength approach to 766 00:34:22,480 --> 00:34:21,169 look at this galaxy m83 we have to look 767 00:34:24,040 --> 00:34:22,490 at different wavelengths to find the 768 00:34:25,450 --> 00:34:24,050 ones that are bright and x-ray versus 769 00:34:28,629 --> 00:34:25,460 the ones that are bright optically and 770 00:34:32,300 --> 00:34:30,680 okay so when we make these color 771 00:34:33,919 --> 00:34:32,310 pictures like it's kind of I kind knows 772 00:34:37,970 --> 00:34:33,929 this but I just wanted to point out that 773 00:34:40,610 --> 00:34:37,980 you know if I make one one image in red 774 00:34:42,980 --> 00:34:40,620 one image in green and one image in blue 775 00:34:44,629 --> 00:34:42,990 then where things are bright in more 776 00:34:47,119 --> 00:34:44,639 than one band you get different colors 777 00:34:49,310 --> 00:34:47,129 okay if it's bright and the blue and the 778 00:34:51,379 --> 00:34:49,320 red you get this kind of pinky magenta 779 00:34:53,419 --> 00:34:51,389 color if you if it's bright and blue and 780 00:34:55,220 --> 00:34:53,429 green you get that cyan color and if 781 00:34:57,290 --> 00:34:55,230 it's bright in red and green you get 782 00:34:59,630 --> 00:34:57,300 yellow and so if I make a color image 783 00:35:01,430 --> 00:34:59,640 out of three different images of 784 00:35:03,980 --> 00:35:01,440 different wavelengths of light or 785 00:35:05,390 --> 00:35:03,990 different data from different 786 00:35:08,240 --> 00:35:05,400 instruments like we just looked at from 787 00:35:10,070 --> 00:35:08,250 Chandra and from Hubble and so forth you 788 00:35:11,420 --> 00:35:10,080 can compare the similarities and 789 00:35:12,890 --> 00:35:11,430 differences by looking at the colors 790 00:35:14,450 --> 00:35:12,900 where they're both bright 791 00:35:16,040 --> 00:35:14,460 that's one of the tricks we play and 792 00:35:18,140 --> 00:35:16,050 then over here I just show that 793 00:35:19,550 --> 00:35:18,150 basically it's not an on/off thing like 794 00:35:21,560 --> 00:35:19,560 this it's basically there's all kinds of 795 00:35:23,650 --> 00:35:21,570 gradation in the color that you get as 796 00:35:26,030 --> 00:35:23,660 you combine those in different amounts 797 00:35:28,700 --> 00:35:26,040 so as we make color pictures we can 798 00:35:30,380 --> 00:35:28,710 actually use that to diagnose what's 799 00:35:32,000 --> 00:35:30,390 going on if we understand what the 800 00:35:36,620 --> 00:35:32,010 images are that went into the the 801 00:35:38,270 --> 00:35:36,630 pictures okay so one of the problems 802 00:35:40,250 --> 00:35:38,280 that we have just looking locally you 803 00:35:42,380 --> 00:35:40,260 say why don't we look at m83 look you 804 00:35:44,180 --> 00:35:42,390 know 15 million light years away in 805 00:35:45,410 --> 00:35:44,190 another galaxy to find supernovae in 806 00:35:47,600 --> 00:35:45,420 this we've got ones in our own galaxy 807 00:35:50,420 --> 00:35:47,610 that we can look at in great detail and 808 00:35:52,760 --> 00:35:50,430 indeed we do but part of the problem is 809 00:35:55,460 --> 00:35:52,770 that we have very few of these very 810 00:35:57,080 --> 00:35:55,470 young objects that we can look at and 811 00:35:59,090 --> 00:35:57,090 understand and kind of put together the 812 00:36:00,980 --> 00:35:59,100 big picture of what's going on this is 813 00:36:02,690 --> 00:36:00,990 the Crab Nebula with Hubble three 814 00:36:05,210 --> 00:36:02,700 different wavelengths of Hubble light 815 00:36:07,520 --> 00:36:05,220 put together into a couple color picture 816 00:36:10,430 --> 00:36:07,530 here and this is the Cassiopeia a 817 00:36:13,160 --> 00:36:10,440 supernova remnant which is a much more 818 00:36:16,280 --> 00:36:13,170 massive star that blew up in our galaxy 819 00:36:17,900 --> 00:36:16,290 and this is the same color coding that I 820 00:36:20,030 --> 00:36:17,910 had on that Kepler picture a minute ago 821 00:36:22,820 --> 00:36:20,040 where the yellow is a Hubble and the red 822 00:36:24,800 --> 00:36:22,830 is the infrared band and the blue and 823 00:36:27,290 --> 00:36:24,810 the green are the x-ray and you can see 824 00:36:28,880 --> 00:36:27,300 how they all mess up there and this in 825 00:36:32,300 --> 00:36:28,890 this explosion which is expanding at 826 00:36:33,980 --> 00:36:32,310 very high velocities even some 300 400 827 00:36:35,750 --> 00:36:33,990 years after the explosion still 828 00:36:37,790 --> 00:36:35,760 expanding at ten or twelve thousand 829 00:36:41,210 --> 00:36:37,800 kilometers per second interestingly 830 00:36:41,450 --> 00:36:41,220 enough the Crab Nebula almost a thousand 831 00:36:44,030 --> 00:36:41,460 years 832 00:36:45,920 --> 00:36:44,040 old and it's only expanding at 1,800 833 00:36:48,950 --> 00:36:45,930 kilometers per second and we think it 834 00:36:51,710 --> 00:36:48,960 came from a much lower mass star so 835 00:36:53,329 --> 00:36:51,720 let's say we have half a dozen of these 836 00:36:55,250 --> 00:36:53,339 kinds of objects or something like that 837 00:36:58,579 --> 00:36:55,260 to look at we've got the mass varying 838 00:37:00,470 --> 00:36:58,589 we've got the expansion the age is 839 00:37:02,240 --> 00:37:00,480 different the expansion velocities are 840 00:37:03,800 --> 00:37:02,250 different how do we take all these 841 00:37:05,450 --> 00:37:03,810 pieces of information and put it 842 00:37:07,849 --> 00:37:05,460 together into a picture when we have so 843 00:37:10,849 --> 00:37:07,859 few objects to kind of put together and 844 00:37:14,359 --> 00:37:10,859 make that picture and just as a another 845 00:37:16,670 --> 00:37:14,369 sign of how crazy these are this 8 or 10 846 00:37:18,859 --> 00:37:16,680 solar mass star we know produced this 847 00:37:20,720 --> 00:37:18,869 inquiry this crazy Crab Nebula pulsar 848 00:37:22,220 --> 00:37:20,730 down here in the center of the object 849 00:37:24,500 --> 00:37:22,230 that is actually what's energizing and 850 00:37:27,589 --> 00:37:24,510 actually accelerating the expansion of 851 00:37:30,349 --> 00:37:27,599 the material from the explosion whereas 852 00:37:32,180 --> 00:37:30,359 this big monster 25 solar mass star that 853 00:37:33,920 --> 00:37:32,190 blew up here made this wimpy little 854 00:37:36,680 --> 00:37:33,930 neutron star down here that we don't 855 00:37:38,540 --> 00:37:36,690 even see any pulses from there so there 856 00:37:40,579 --> 00:37:38,550 is a stellar remnant left behind from 857 00:37:43,640 --> 00:37:40,589 the explosion but it's not anything that 858 00:37:47,180 --> 00:37:43,650 would knock your socks off like the Crab 859 00:37:50,990 --> 00:37:47,190 Nebula pulsar so very few objects to 860 00:37:53,450 --> 00:37:51,000 understand the parameter space and many 861 00:37:55,640 --> 00:37:53,460 things changing it makes it hard and so 862 00:37:57,349 --> 00:37:55,650 we'd like to find a lot of these young 863 00:37:58,609 --> 00:37:57,359 remnants and look at them especially if 864 00:38:00,440 --> 00:37:58,619 they were all at the same distance you 865 00:38:02,420 --> 00:38:00,450 take the distance difference out of it 866 00:38:03,650 --> 00:38:02,430 you can look at that sample of objects 867 00:38:06,980 --> 00:38:03,660 that are all at the same distance and 868 00:38:09,410 --> 00:38:06,990 understand systematically what's going 869 00:38:10,700 --> 00:38:09,420 on with massive star supernova remnants 870 00:38:15,920 --> 00:38:10,710 so that was one of the motivations for 871 00:38:17,540 --> 00:38:15,930 going to how to m83 alright so I'm gonna 872 00:38:18,680 --> 00:38:17,550 leave the Crab Nebula behind now that 873 00:38:20,359 --> 00:38:18,690 was kind of at the lower end of a 874 00:38:22,609 --> 00:38:20,369 massive star these are all these are 875 00:38:25,339 --> 00:38:22,619 three supernova remnants of we think 876 00:38:27,589 --> 00:38:25,349 very massive stars here's Cassie again 877 00:38:30,589 --> 00:38:27,599 in our galaxy and below below here I 878 00:38:33,050 --> 00:38:30,599 just have a blow-up of some Hubble data 879 00:38:36,020 --> 00:38:33,060 that that shows some of the detail in 880 00:38:38,120 --> 00:38:36,030 this stuff this is star stuff this is 881 00:38:40,550 --> 00:38:38,130 the guts of the massive star that blew 882 00:38:42,349 --> 00:38:40,560 up and the material is still in the 883 00:38:45,260 --> 00:38:42,359 process of flying out into space at very 884 00:38:46,820 --> 00:38:45,270 high velocities and eventually it will 885 00:38:49,160 --> 00:38:46,830 blend back into the interstellar medium 886 00:38:52,209 --> 00:38:49,170 and maybe participate in the next round 887 00:38:55,689 --> 00:38:52,219 of star formation that will have 888 00:38:57,849 --> 00:38:55,699 abundances then the current ones do okay 889 00:39:00,279 --> 00:38:57,859 this is an object in a small magellanic 890 00:39:03,160 --> 00:39:00,289 cloud that is very similar to this only 891 00:39:05,589 --> 00:39:03,170 it's larger it's older but the only 892 00:39:07,900 --> 00:39:05,599 thing we see with Hubble this blue stuff 893 00:39:09,309 --> 00:39:07,910 that you see in that picture is almost 894 00:39:11,529 --> 00:39:09,319 pure oxygen 895 00:39:14,109 --> 00:39:11,539 it's from the layer of the star that 896 00:39:15,249 --> 00:39:14,119 produced oxygen there if you took a 897 00:39:16,749 --> 00:39:15,259 spectrum of that you would see there 898 00:39:19,449 --> 00:39:16,759 would be some neon and some other things 899 00:39:22,150 --> 00:39:19,459 in there but as you see no hydrogen it's 900 00:39:24,969 --> 00:39:22,160 all the star stuff that's flying out 901 00:39:26,979 --> 00:39:24,979 into space this object is in the Large 902 00:39:31,809 --> 00:39:26,989 Magellanic Cloud or neighboring galaxies 903 00:39:33,519 --> 00:39:31,819 of ours and it is larger it has a kind 904 00:39:35,229 --> 00:39:33,529 of an outer shell here that's starting 905 00:39:36,519 --> 00:39:35,239 to form from the blast wave going out of 906 00:39:38,439 --> 00:39:36,529 the space and starting to sweep up 907 00:39:40,809 --> 00:39:38,449 surrounding material so you're getting 908 00:39:43,359 --> 00:39:40,819 that outer shell starting to form but 909 00:39:46,420 --> 00:39:43,369 down in the center here this blue and 910 00:39:47,920 --> 00:39:46,430 green stuff in this picture is this kind 911 00:39:50,499 --> 00:39:47,930 of stuff it's the star stuff still 912 00:39:53,890 --> 00:39:50,509 visible even though it's a much much 913 00:39:55,989 --> 00:39:53,900 older object and to put those three in a 914 00:39:58,329 --> 00:39:55,999 little more of a context for you and in 915 00:40:01,479 --> 00:39:58,339 this graph I try to graphic I try to 916 00:40:05,109 --> 00:40:01,489 show you their relative sizes to give 917 00:40:07,239 --> 00:40:05,119 you a little sense so Cassie 340 years 918 00:40:10,269 --> 00:40:07,249 since the explosion 18 light-years in 919 00:40:13,599 --> 00:40:10,279 size yellow 102 this one with the 920 00:40:15,969 --> 00:40:13,609 phonebook name is about 1200 years old 921 00:40:18,339 --> 00:40:15,979 and is a little over 40 kilometres per 922 00:40:21,009 --> 00:40:18,349 second this is expanding at say 10,000 923 00:40:22,959 --> 00:40:21,019 this is 2,000 and over here the outer 924 00:40:25,479 --> 00:40:22,969 structure is not expanding rapidly but 925 00:40:27,819 --> 00:40:25,489 that green stuff the oxygen stuff in 926 00:40:30,609 --> 00:40:27,829 there is still expanding and a thousand 927 00:40:33,880 --> 00:40:30,619 kilometers per second even some 3,000 928 00:40:35,739 --> 00:40:33,890 years or more after the explosion and so 929 00:40:37,959 --> 00:40:35,749 if we wanted to find this kind of object 930 00:40:39,910 --> 00:40:37,969 in other galaxies we would want to look 931 00:40:41,859 --> 00:40:39,920 for high velocities and we would want to 932 00:40:44,709 --> 00:40:41,869 look for these funny abundances compared 933 00:40:47,589 --> 00:40:44,719 to the surrounding gas and that's one of 934 00:40:49,299 --> 00:40:47,599 the ways we try to find them I'm just 935 00:40:52,479 --> 00:40:49,309 taking that one step further I like to 936 00:40:54,249 --> 00:40:52,489 make this point because you know this is 937 00:40:56,109 --> 00:40:54,259 thought of as a young object the veil 938 00:40:57,549 --> 00:40:56,119 nebula the Cygnus loop is thought of 939 00:40:59,079 --> 00:40:57,559 it's kind of an old or a middle-aged 940 00:41:01,419 --> 00:40:59,089 object and yet sighs this is the 941 00:41:03,959 --> 00:41:01,429 relative sizes again not too different 942 00:41:05,230 --> 00:41:03,969 88 light years versus 82 light years 943 00:41:07,630 --> 00:41:05,240 inside 944 00:41:09,970 --> 00:41:07,640 again this outer shell is thought to be 945 00:41:12,430 --> 00:41:09,980 sort of the wall of a cavity that was 946 00:41:14,800 --> 00:41:12,440 blown by the wind from the star before 947 00:41:17,080 --> 00:41:14,810 it blew up so there's a cavity that it's 948 00:41:18,460 --> 00:41:17,090 expanding into that's the same model we 949 00:41:20,350 --> 00:41:18,470 have for the Cygnus loop this bright 950 00:41:21,790 --> 00:41:20,360 emission on the outside edges where the 951 00:41:24,820 --> 00:41:21,800 shock wave is finally starting to hit 952 00:41:26,230 --> 00:41:24,830 the outside edges of a cavity so the two 953 00:41:28,060 --> 00:41:26,240 stars the blue up here could be very 954 00:41:31,360 --> 00:41:28,070 similar to each other and yet we don't 955 00:41:33,520 --> 00:41:31,370 see the oxygen-rich the ejecta in this 956 00:41:35,380 --> 00:41:33,530 one they're starting to tease it out of 957 00:41:36,640 --> 00:41:35,390 very deep x-ray observations in the 958 00:41:38,320 --> 00:41:36,650 Cygnus oh they're starting to see some 959 00:41:40,690 --> 00:41:38,330 of that enhancement but most of that 960 00:41:43,570 --> 00:41:40,700 stuff is blended back in or faded away 961 00:41:45,250 --> 00:41:43,580 at this point and so this object is on 962 00:41:46,450 --> 00:41:45,260 its way to becoming something like the 963 00:41:50,110 --> 00:41:46,460 Cygnus of when they're about the same 964 00:41:51,340 --> 00:41:50,120 the same size this has nothing to do 965 00:41:52,450 --> 00:41:51,350 with the rest of the talk but I had to 966 00:41:55,210 --> 00:41:52,460 throw it in here you see this little 967 00:41:57,070 --> 00:41:55,220 white box on the side there was this 968 00:41:59,260 --> 00:41:57,080 wonderful picture of the Cygnus loop 969 00:42:02,140 --> 00:41:59,270 just that tiny little section that was 970 00:42:03,940 --> 00:42:02,150 released last year that makes the point 971 00:42:05,470 --> 00:42:03,950 also that you know you use the different 972 00:42:08,260 --> 00:42:05,480 colors to represent things so we've got 973 00:42:11,260 --> 00:42:08,270 an oxygen hydrogen and a sulphur band in 974 00:42:12,640 --> 00:42:11,270 blue red and green and then you can see 975 00:42:15,580 --> 00:42:12,650 how the colors are mixing together you 976 00:42:17,650 --> 00:42:15,590 get the yellows which means that H alpha 977 00:42:19,150 --> 00:42:17,660 and the software too are bright you see 978 00:42:21,550 --> 00:42:19,160 the places where the blue is dominant 979 00:42:23,020 --> 00:42:21,560 where the oxygen high ionization oxygen 980 00:42:24,940 --> 00:42:23,030 is dominant and so forth so you can 981 00:42:28,260 --> 00:42:24,950 again you get a sense for what how you 982 00:42:30,580 --> 00:42:28,270 get diagnostic power out of the color 983 00:42:32,980 --> 00:42:30,590 images if you understand something about 984 00:42:35,620 --> 00:42:32,990 what's going into the picture but that's 985 00:42:38,260 --> 00:42:35,630 just a spectacular picture this cloud up 986 00:42:39,610 --> 00:42:38,270 here is probably unrelated directly to 987 00:42:41,110 --> 00:42:39,620 this it's either the foreground or 988 00:42:43,120 --> 00:42:41,120 background and just happens to be in the 989 00:42:46,540 --> 00:42:43,130 frame out here and there's a one light 990 00:42:48,250 --> 00:42:46,550 one light-year bar across there so so 991 00:42:50,170 --> 00:42:48,260 the whole object of course is much much 992 00:42:52,240 --> 00:42:50,180 much much larger we're looking at a tiny 993 00:42:57,520 --> 00:42:52,250 little piece of it and this this Hubble 994 00:43:00,430 --> 00:42:57,530 picture this picture is 18 orbits of 995 00:43:02,200 --> 00:43:00,440 Hubble data about a hundred separate 996 00:43:03,970 --> 00:43:02,210 images and those different filters all 997 00:43:06,900 --> 00:43:03,980 align then put together this was 998 00:43:09,580 --> 00:43:06,910 actually three by two 999 00:43:11,170 --> 00:43:09,590 wipsy three fields of view for the 1000 00:43:13,720 --> 00:43:11,180 Hubble telescope so this has been all 1001 00:43:15,370 --> 00:43:13,730 stitched together four six six fields of 1002 00:43:17,240 --> 00:43:15,380 the of the wide field camera to put 1003 00:43:20,120 --> 00:43:17,250 together this picture of that one 1004 00:43:22,730 --> 00:43:20,130 piece of the cygnets loop Hubble's job 1005 00:43:24,920 --> 00:43:22,740 is to look at small areas of the sky in 1006 00:43:29,300 --> 00:43:24,930 very great detail that's that's this 1007 00:43:31,490 --> 00:43:29,310 reason for existence basically okay well 1008 00:43:33,050 --> 00:43:31,500 we're almost to m83 I just want to kind 1009 00:43:34,850 --> 00:43:33,060 of give you the big picture here first I 1010 00:43:37,550 --> 00:43:34,860 mean the idea remember is that we want 1011 00:43:40,010 --> 00:43:37,560 to understand the star formation 1012 00:43:42,500 --> 00:43:40,020 processes and the whole evolution of 1013 00:43:44,840 --> 00:43:42,510 stars and we want to do that for the 1014 00:43:47,090 --> 00:43:44,850 four galaxies in the local universe it 1015 00:43:48,950 --> 00:43:47,100 turns out m83 is a prime testing ground 1016 00:43:51,140 --> 00:43:48,960 for doing this because you want to 1017 00:43:52,880 --> 00:43:51,150 understand by comparing local galaxies 1018 00:43:55,220 --> 00:43:52,890 to more distant galaxies whether these 1019 00:43:57,260 --> 00:43:55,230 processes that that that guide this 1020 00:44:00,170 --> 00:43:57,270 stuff are universal processes or whether 1021 00:44:01,790 --> 00:44:00,180 there are differences and the part that 1022 00:44:03,710 --> 00:44:01,800 I'm really most interested in most 1023 00:44:05,420 --> 00:44:03,720 involved in is in finding the supernova 1024 00:44:09,500 --> 00:44:05,430 remnants which is just the one part of 1025 00:44:10,400 --> 00:44:09,510 this bigger picture so most of the rest 1026 00:44:11,990 --> 00:44:10,410 of this I'm going to be talking about 1027 00:44:13,910 --> 00:44:12,000 trying to find the supernova remnants 1028 00:44:15,350 --> 00:44:13,920 and telling you how we do that so here's 1029 00:44:18,200 --> 00:44:15,360 a ground-based picture very nice 1030 00:44:20,390 --> 00:44:18,210 ground-based picture of m83 about 15 1031 00:44:22,670 --> 00:44:20,400 million light years away one arcsecond 1032 00:44:24,830 --> 00:44:22,680 is about 72 light years and one 1033 00:44:26,300 --> 00:44:24,840 arcsecond is kind of as you a lot of 1034 00:44:27,950 --> 00:44:26,310 amateur astronomers out here I presume 1035 00:44:29,570 --> 00:44:27,960 were people that know that's basically 1036 00:44:31,430 --> 00:44:29,580 kind of what you get from ground-based 1037 00:44:33,260 --> 00:44:31,440 observations is about one arc second or 1038 00:44:35,000 --> 00:44:33,270 sometimes a little bit worse sometimes a 1039 00:44:36,560 --> 00:44:35,010 little bit better but of course Hubble 1040 00:44:38,090 --> 00:44:36,570 can do about twenty times better than 1041 00:44:40,490 --> 00:44:38,100 that so we're getting down to just a few 1042 00:44:42,260 --> 00:44:40,500 light years type resolution with Hubble 1043 00:44:44,480 --> 00:44:42,270 pictures when we look at this thing 1044 00:44:46,250 --> 00:44:44,490 that's 15 million light years away and 1045 00:44:48,200 --> 00:44:46,260 we can still resolve things that's just 1046 00:44:51,410 --> 00:44:48,210 a few light-years in size that's pretty 1047 00:44:53,030 --> 00:44:51,420 spectacular okay it's a called a barred 1048 00:44:54,650 --> 00:44:53,040 spiral galaxy there's certainly other 1049 00:44:56,150 --> 00:44:54,660 galaxies and have more prominent bars 1050 00:44:58,220 --> 00:44:56,160 but you can see it's kind of extended 1051 00:45:01,130 --> 00:44:58,230 here it's got this very bright nucleus 1052 00:45:04,010 --> 00:45:01,140 where star formation is just happening 1053 00:45:06,230 --> 00:45:04,020 at a tremendous burst but you see also a 1054 00:45:08,210 --> 00:45:06,240 lot of these h2 regions around out 1055 00:45:10,820 --> 00:45:08,220 through the spiral arms where where star 1056 00:45:12,110 --> 00:45:10,830 formation is happening it turns out this 1057 00:45:14,120 --> 00:45:12,120 galaxy is a great place to look for 1058 00:45:17,180 --> 00:45:14,130 supernova remnants because it's produced 1059 00:45:19,430 --> 00:45:17,190 a ton of supernovae we've actually seen 1060 00:45:22,390 --> 00:45:19,440 over the last hundred years six 1061 00:45:25,100 --> 00:45:22,400 supernovae in m83 1062 00:45:27,710 --> 00:45:25,110 we found another object that I'll 1063 00:45:29,300 --> 00:45:27,720 mention briefly as we go along that has 1064 00:45:30,589 --> 00:45:29,310 to be less than 100 years old that was 1065 00:45:33,259 --> 00:45:30,599 probably a supernova that 1066 00:45:35,059 --> 00:45:33,269 did not see maybe it happened when 1067 00:45:36,890 --> 00:45:35,069 anybody through is behind the Sun we 1068 00:45:38,269 --> 00:45:36,900 don't know exactly but anyway there's 1069 00:45:39,559 --> 00:45:38,279 another one that's young that's so 1070 00:45:42,920 --> 00:45:39,569 probably seven of them in the last 1071 00:45:47,569 --> 00:45:42,930 century interestingly enough none since 1072 00:45:49,460 --> 00:45:47,579 1983 we are do we are do we had seven of 1073 00:45:51,140 --> 00:45:49,470 them in the first part of the 20th 1074 00:45:52,880 --> 00:45:51,150 century and now none since thinking 83 1075 00:45:55,329 --> 00:45:52,890 so we ought to be seeing some super 1076 00:45:57,710 --> 00:45:55,339 novae coming for maybe three pretty soon 1077 00:45:59,509 --> 00:45:57,720 and just for context again this is a 1078 00:46:00,979 --> 00:45:59,519 quarter of a degree field of view that I 1079 00:46:02,539 --> 00:46:00,989 was showing here of course the full moon 1080 00:46:05,989 --> 00:46:02,549 is about a half a degree across so it's 1081 00:46:07,279 --> 00:46:05,999 a sizable galaxy on the sky but 1082 00:46:09,440 --> 00:46:07,289 interestingly enough if you put this 1083 00:46:11,390 --> 00:46:09,450 where the Milky Way is this this whole 1084 00:46:13,219 --> 00:46:11,400 thing is you would like put two 1085 00:46:14,660 --> 00:46:13,229 side-by-side and two up and down that's 1086 00:46:16,400 --> 00:46:14,670 gonna be about the size of the Milky Way 1087 00:46:18,859 --> 00:46:16,410 galaxy so it's actually a relatively 1088 00:46:19,579 --> 00:46:18,869 small spiral galaxy compared to our 1089 00:46:24,620 --> 00:46:19,589 Milky Way 1090 00:46:26,120 --> 00:46:24,630 I mentioned that it had six or possibly 1091 00:46:28,819 --> 00:46:26,130 seven supernovae here's where they are 1092 00:46:30,349 --> 00:46:28,829 located across the galaxy some of them 1093 00:46:33,440 --> 00:46:30,359 are very close to star forming regions 1094 00:46:35,390 --> 00:46:33,450 some of them are are not one is right 1095 00:46:36,890 --> 00:46:35,400 down here in the in this bright nucleus 1096 00:46:40,249 --> 00:46:36,900 where there's tremendous activity going 1097 00:46:41,900 --> 00:46:40,259 on near star formation again your star 1098 00:46:43,940 --> 00:46:41,910 formation up here I'll talk about this 1099 00:46:45,769 --> 00:46:43,950 object and this object this is the one 1100 00:46:48,559 --> 00:46:45,779 that I think we found that has to be 1101 00:46:50,950 --> 00:46:48,569 young but the supernova was not seen but 1102 00:46:53,809 --> 00:46:50,960 the point is with this many supernovae 1103 00:46:55,370 --> 00:46:53,819 less than a hundred years old if we want 1104 00:46:58,099 --> 00:46:55,380 to take what you want to take a thousand 1105 00:47:00,140 --> 00:46:58,109 or 1500 years as a young supernova 1106 00:47:03,170 --> 00:47:00,150 remnant there ought to be 6070 maybe 1107 00:47:05,509 --> 00:47:03,180 even a hundred of these young ejecta 1108 00:47:07,279 --> 00:47:05,519 dominated supernova remnants in this 1109 00:47:08,930 --> 00:47:07,289 galaxy and so that's why one of the 1110 00:47:10,279 --> 00:47:08,940 reasons we wanted to look here we also 1111 00:47:12,769 --> 00:47:10,289 wanted to find the normal supernova 1112 00:47:14,779 --> 00:47:12,779 remnants like the Cygnus loop and so the 1113 00:47:18,049 --> 00:47:14,789 search actually looked for both of those 1114 00:47:20,059 --> 00:47:18,059 things so just very briefly we used a 1115 00:47:22,519 --> 00:47:20,069 large ground-based telescope here at Las 1116 00:47:25,299 --> 00:47:22,529 Campanas Observatory for a ground-based 1117 00:47:28,160 --> 00:47:25,309 search and we actually found 225 1118 00:47:30,319 --> 00:47:28,170 supernova remnant candidates from that 1119 00:47:32,329 --> 00:47:30,329 ground-based search so the question is 1120 00:47:33,829 --> 00:47:32,339 why do we need Hubble well we could find 1121 00:47:35,959 --> 00:47:33,839 them but we couldn't measure their sizes 1122 00:47:38,509 --> 00:47:35,969 from the ground even with very excellent 1123 00:47:40,190 --> 00:47:38,519 ground-based data most of the objects we 1124 00:47:41,870 --> 00:47:40,200 wanted to get you know see if they had 1125 00:47:44,300 --> 00:47:41,880 shells or if they were very small 1126 00:47:46,010 --> 00:47:44,310 objects or whatever we couldn't do with 1127 00:47:47,750 --> 00:47:46,020 with Magellan and so we had to do that 1128 00:47:50,560 --> 00:47:47,760 with with Hubble and so down here is the 1129 00:47:53,030 --> 00:47:50,570 Hubble part of the project we also have 1130 00:47:55,640 --> 00:47:53,040 730 Killa seconds that's a lot of time 1131 00:47:57,350 --> 00:47:55,650 on the Chandra x-ray Observatory to take 1132 00:47:59,510 --> 00:47:57,360 a very deep x-ray picture of this galaxy 1133 00:48:01,550 --> 00:47:59,520 we found four hundred and forty point 1134 00:48:02,990 --> 00:48:01,560 sources and lots of the few submission 1135 00:48:04,220 --> 00:48:03,000 I'll show you that and then there are 1136 00:48:06,460 --> 00:48:04,230 other datasets that we're working on 1137 00:48:08,630 --> 00:48:06,470 including radio again multi-wavelength 1138 00:48:11,330 --> 00:48:08,640 spectroscopic follow up and I'll show 1139 00:48:13,400 --> 00:48:11,340 you a couple of spectra from that as we 1140 00:48:17,240 --> 00:48:13,410 go along but I basically won't talk 1141 00:48:20,750 --> 00:48:17,250 about those very much that part of it so 1142 00:48:24,350 --> 00:48:20,760 there is I showed you here the optical 1143 00:48:26,870 --> 00:48:24,360 picture of the galaxy right and here is 1144 00:48:28,760 --> 00:48:26,880 this deep x-ray picture of the galaxy - 1145 00:48:30,380 --> 00:48:28,770 approximately the same scale you can 1146 00:48:32,780 --> 00:48:30,390 even kind of see the spiral arms and 1147 00:48:36,460 --> 00:48:32,790 that red diffuse gas there you see this 1148 00:48:40,130 --> 00:48:36,470 incredible x-ray bright region 1149 00:48:42,440 --> 00:48:40,140 associated with the starburst nucleus in 1150 00:48:44,540 --> 00:48:42,450 there and all these little point sources 1151 00:48:46,760 --> 00:48:44,550 and vast majority of those point sources 1152 00:48:49,310 --> 00:48:46,770 are actually in n83 a lot of the 1153 00:48:52,220 --> 00:48:49,320 brighter whitish looking ones are x-ray 1154 00:48:53,840 --> 00:48:52,230 binary stars and you can see that 1155 00:48:55,130 --> 00:48:53,850 because some of those sources vary over 1156 00:48:57,350 --> 00:48:55,140 time and whatnot because they're in 1157 00:48:58,640 --> 00:48:57,360 binary orbits and the things that don't 1158 00:49:00,890 --> 00:48:58,650 look too impressive on here a lot of 1159 00:49:03,140 --> 00:49:00,900 these little little red red dots or 1160 00:49:05,450 --> 00:49:03,150 yellow dots and places are oftentimes 1161 00:49:07,280 --> 00:49:05,460 are associated with optical supernova 1162 00:49:09,320 --> 00:49:07,290 remnants so we have a lot of supernovae 1163 00:49:11,900 --> 00:49:09,330 that show up the color coding here goes 1164 00:49:14,000 --> 00:49:11,910 from relatively low energy x-rays in the 1165 00:49:16,520 --> 00:49:14,010 red up to the higher and their energy 1166 00:49:18,950 --> 00:49:16,530 x-rays in the blue and so this diffuse 1167 00:49:20,990 --> 00:49:18,960 gas this is the brightest diffuse x-ray 1168 00:49:23,270 --> 00:49:21,000 emission that we have seen in any spiral 1169 00:49:24,440 --> 00:49:23,280 galaxy by the way so if it doesn't look 1170 00:49:26,360 --> 00:49:24,450 too impressive to you you should see 1171 00:49:27,110 --> 00:49:26,370 some of the other galaxies this looks 1172 00:49:29,870 --> 00:49:27,120 pretty good 1173 00:49:33,080 --> 00:49:29,880 and just that tells us that there is hot 1174 00:49:35,270 --> 00:49:33,090 low-density gas permeating the spiral 1175 00:49:38,270 --> 00:49:35,280 arms of this galaxy and that has been 1176 00:49:40,580 --> 00:49:38,280 energized by the stellar formation the 1177 00:49:43,310 --> 00:49:40,590 winds from the stars and the supernova 1178 00:49:45,440 --> 00:49:43,320 explosions over time have energized the 1179 00:49:48,550 --> 00:49:45,450 interstellar medium of this galaxy and 1180 00:49:53,060 --> 00:49:48,560 we get this incredible bright diffuse 1181 00:49:54,890 --> 00:49:53,070 emission also just a little blow-up and 1182 00:49:56,870 --> 00:49:54,900 rescaled so that it's not burned out 1183 00:49:57,410 --> 00:49:56,880 this nuclear region has a tremendous 1184 00:50:00,230 --> 00:49:57,420 number of 1185 00:50:01,760 --> 00:50:00,240 sources and the few submission in there 1186 00:50:03,740 --> 00:50:01,770 as well it's a very complicated reason 1187 00:50:05,089 --> 00:50:03,750 some of those again are aligned with 1188 00:50:07,039 --> 00:50:05,099 supernova remnants and other ones that 1189 00:50:09,049 --> 00:50:07,049 are x-ray binaries in that very active 1190 00:50:11,390 --> 00:50:09,059 nucleus but it's so confused in there 1191 00:50:17,120 --> 00:50:11,400 we've mostly set that aside and worked 1192 00:50:19,880 --> 00:50:17,130 on the outer part of the galaxy the big 1193 00:50:21,319 --> 00:50:19,890 picture here is that m83 although it's 1194 00:50:23,150 --> 00:50:21,329 hanging out there looks like a nice big 1195 00:50:26,420 --> 00:50:23,160 bright spiral galaxy all by itself is 1196 00:50:28,190 --> 00:50:26,430 actually much more extended than we give 1197 00:50:29,720 --> 00:50:28,200 it credit for this is the part we've 1198 00:50:32,359 --> 00:50:29,730 been looking at here in the bright part 1199 00:50:34,539 --> 00:50:32,369 this is galaxies ultraviolet images and 1200 00:50:37,339 --> 00:50:34,549 the red and this picture is actually 1201 00:50:39,530 --> 00:50:37,349 radio h1 emission hydrogen emission that 1202 00:50:43,130 --> 00:50:39,540 shows that there is very faint diffuse 1203 00:50:44,839 --> 00:50:43,140 gas way out there and the blue light 1204 00:50:46,640 --> 00:50:44,849 that you see way out here is star 1205 00:50:48,859 --> 00:50:46,650 formation that is actually happening way 1206 00:50:49,490 --> 00:50:48,869 out here away from the bright part of 1207 00:50:51,740 --> 00:50:49,500 the galaxy 1208 00:50:53,329 --> 00:50:51,750 this probably indicates that at some 1209 00:50:55,160 --> 00:50:53,339 point in the not-too-distant past and 1210 00:50:57,260 --> 00:50:55,170 maybe three had an interaction with 1211 00:50:58,910 --> 00:50:57,270 another galaxy and we don't see that 1212 00:51:00,859 --> 00:50:58,920 other galaxy right now but it was enough 1213 00:51:02,990 --> 00:51:00,869 to kind of really disturb the outer 1214 00:51:04,910 --> 00:51:03,000 structure of m83 1215 00:51:08,289 --> 00:51:04,920 and maybe what triggered this big burst 1216 00:51:10,609 --> 00:51:08,299 of star formation in the galaxy itself 1217 00:51:14,900 --> 00:51:10,619 so that's a much larger scale picture 1218 00:51:16,549 --> 00:51:14,910 than what we were looking at before okay 1219 00:51:19,760 --> 00:51:16,559 so how do we find supernova remnants 1220 00:51:22,400 --> 00:51:19,770 these are spectrum aren't they beautiful 1221 00:51:25,130 --> 00:51:22,410 people like rainbows for spectra for an 1222 00:51:27,710 --> 00:51:25,140 astronomer a graph of intensity versus 1223 00:51:29,390 --> 00:51:27,720 wavelength or versus color blue to red 1224 00:51:30,920 --> 00:51:29,400 in this case these are optical spectra 1225 00:51:33,289 --> 00:51:30,930 intensity 1226 00:51:35,390 --> 00:51:33,299 these are Specter to an astronomer and 1227 00:51:36,890 --> 00:51:35,400 what you see here you see some low-level 1228 00:51:38,900 --> 00:51:36,900 noise going across everything you see 1229 00:51:40,430 --> 00:51:38,910 these spikes that go up this is called 1230 00:51:43,370 --> 00:51:40,440 an emission line spectrum if you look at 1231 00:51:45,319 --> 00:51:43,380 a gas cloud on h2 region or a supernova 1232 00:51:48,319 --> 00:51:45,329 remnant you see emission lines these 1233 00:51:49,880 --> 00:51:48,329 spikes in the spectrum okay and despite 1234 00:51:51,650 --> 00:51:49,890 the relative intensities of the spikes 1235 00:51:53,569 --> 00:51:51,660 change as you look at different objects 1236 00:51:57,170 --> 00:51:53,579 as you look at different kinds of 1237 00:51:59,960 --> 00:51:57,180 objects okay so this is a shock heated 1238 00:52:01,549 --> 00:51:59,970 supernova remnant and what you see is 1239 00:52:04,700 --> 00:52:01,559 that this little line of sulphur out 1240 00:52:06,170 --> 00:52:04,710 here is much stronger relative to the 1241 00:52:09,020 --> 00:52:06,180 hydrogen and there's actually nitrogen 1242 00:52:11,180 --> 00:52:09,030 lines here right next to it the software 1243 00:52:15,319 --> 00:52:11,190 to jumps up the self-reliance jump 1244 00:52:17,150 --> 00:52:15,329 way up the oxygen lines in m83 get very 1245 00:52:20,089 --> 00:52:17,160 strong and many supernovae retinas not 1246 00:52:22,849 --> 00:52:20,099 all of them whereas in the photo star 1247 00:52:26,720 --> 00:52:22,859 light ionized gas the oxygen is very 1248 00:52:28,640 --> 00:52:26,730 weak the sulfur is very weak so knowing 1249 00:52:30,589 --> 00:52:28,650 what the spectra look like now I want to 1250 00:52:32,839 --> 00:52:30,599 say let's go and take pictures and we're 1251 00:52:36,680 --> 00:52:32,849 going to take little filters that just 1252 00:52:37,760 --> 00:52:36,690 get the light from pieces of the 1253 00:52:39,109 --> 00:52:37,770 spectrum and we're going to take 1254 00:52:43,250 --> 00:52:39,119 pictures and then we're going to do an 1255 00:52:44,960 --> 00:52:43,260 RGB of these filters and look for color 1256 00:52:48,800 --> 00:52:44,970 combinations that will tell us which 1257 00:52:49,910 --> 00:52:48,810 objects have strong sulfur - okay and 1258 00:52:52,760 --> 00:52:49,920 that's how we find the supernova 1259 00:52:54,640 --> 00:52:52,770 remnants for the ejecta dominated guys 1260 00:52:56,900 --> 00:52:54,650 it's a little bit different this is a 1261 00:52:59,720 --> 00:52:56,910 spectrum and integrative spectrum of 1262 00:53:01,940 --> 00:52:59,730 Caffe in our galaxy first thing you 1263 00:53:03,890 --> 00:53:01,950 notice of course is the lines are huge 1264 00:53:08,359 --> 00:53:03,900 broad lines that's from that high 1265 00:53:10,579 --> 00:53:08,369 velocity of the ejecta still moving they 1266 00:53:11,960 --> 00:53:10,589 aren't all that broad but but they don't 1267 00:53:13,940 --> 00:53:11,970 have to be that broad for us to see it 1268 00:53:15,559 --> 00:53:13,950 they just have to be broader than then 1269 00:53:16,790 --> 00:53:15,569 we see in these kind of spectra so if 1270 00:53:19,550 --> 00:53:16,800 you saw these things broadened you would 1271 00:53:21,410 --> 00:53:19,560 know that you get high velocity okay I 1272 00:53:23,809 --> 00:53:21,420 say okay so here's my oxygen filter 1273 00:53:26,660 --> 00:53:23,819 here's my H alpha filter there's almost 1274 00:53:28,370 --> 00:53:26,670 no H alpha and the sum of what's there 1275 00:53:30,890 --> 00:53:28,380 is not really related to the KSA and 1276 00:53:33,050 --> 00:53:30,900 then there's a sulphur - filter here so 1277 00:53:35,329 --> 00:53:33,060 this object would look bright and oxygen 1278 00:53:38,000 --> 00:53:35,339 bright and sulfur and almost no H alpha 1279 00:53:39,589 --> 00:53:38,010 or some of the oxygen rich reminisce 1280 00:53:42,500 --> 00:53:39,599 don't have sulphur either so that would 1281 00:53:44,180 --> 00:53:42,510 be right here and not much in either of 1282 00:53:46,400 --> 00:53:44,190 those two bands and so if I found things 1283 00:53:48,800 --> 00:53:46,410 like color coded this blue let's say 1284 00:53:52,220 --> 00:53:48,810 then things that look really blue ought 1285 00:53:54,410 --> 00:53:52,230 to be dominated by the do three emission 1286 00:53:58,910 --> 00:53:54,420 so that's how we find the ejected 1287 00:54:01,130 --> 00:53:58,920 dominated guys where we try to we can 1288 00:54:04,309 --> 00:54:01,140 get confused with just the optical data 1289 00:54:07,490 --> 00:54:04,319 here because planetary nebulae from low 1290 00:54:10,099 --> 00:54:07,500 mass stars also can have strong oxygen 3 1291 00:54:13,599 --> 00:54:10,109 and so the other thing we need is like 1292 00:54:16,490 --> 00:54:13,609 cafe we know we have this really strong 1293 00:54:18,500 --> 00:54:16,500 soft x-ray emission as well so we need 1294 00:54:21,079 --> 00:54:18,510 to see something that's bright and 1295 00:54:22,200 --> 00:54:21,089 oxygen and has an Associated x-ray 1296 00:54:23,820 --> 00:54:22,210 source and number 1297 00:54:25,410 --> 00:54:23,830 sure that we've got and ejected 1298 00:54:30,000 --> 00:54:25,420 dominated remnant otherwise it may just 1299 00:54:30,450 --> 00:54:30,010 be a planetary nebula so here's the 1300 00:54:33,510 --> 00:54:30,460 trick 1301 00:54:35,849 --> 00:54:33,520 all right we've h-alpha in red we put 1302 00:54:38,550 --> 00:54:35,859 oxygen three in blue and we put the 1303 00:54:40,170 --> 00:54:38,560 sulfur two in green now the sulfur to 1304 00:54:42,120 --> 00:54:40,180 line is actually in the red part of the 1305 00:54:44,040 --> 00:54:42,130 spectrum but if I did red red and blue 1306 00:54:46,079 --> 00:54:44,050 that I don't have any diagnostic power 1307 00:54:48,480 --> 00:54:46,089 right so I've made the sulfur to green 1308 00:54:50,790 --> 00:54:48,490 and now things that are yellow are 1309 00:54:52,560 --> 00:54:50,800 strong in sulfur Q and H alpha those are 1310 00:54:56,220 --> 00:54:52,570 the normal remnants if I find things 1311 00:54:57,510 --> 00:54:56,230 that are blue or in the cyan I'm pretty 1312 00:54:59,430 --> 00:54:57,520 sure that I've got something that might 1313 00:55:02,849 --> 00:54:59,440 be the ejecta dominated thing and that's 1314 00:55:04,109 --> 00:55:02,859 that's the trick that we play and so 1315 00:55:06,020 --> 00:55:04,119 here's a little example and I'm showing 1316 00:55:08,010 --> 00:55:06,030 you the black and white images 1317 00:55:09,599 --> 00:55:08,020 individually first and then here's the 1318 00:55:12,420 --> 00:55:09,609 color image down here that I'll get to 1319 00:55:14,609 --> 00:55:12,430 in a second so the trick also is that 1320 00:55:16,500 --> 00:55:14,619 when we take images in these emission 1321 00:55:18,630 --> 00:55:16,510 line filters you also get some Starlight 1322 00:55:20,940 --> 00:55:18,640 and so you take a picture that just look 1323 00:55:23,250 --> 00:55:20,950 gets the stars and you scale that and 1324 00:55:25,650 --> 00:55:23,260 subtract it away so you get a pure 1325 00:55:27,089 --> 00:55:25,660 emission line image so here except for 1326 00:55:29,250 --> 00:55:27,099 maybe a few little stellar residuals 1327 00:55:31,950 --> 00:55:29,260 like this you know this is the oxygen 3 1328 00:55:34,410 --> 00:55:31,960 emission only here's the H alpha 1329 00:55:37,020 --> 00:55:34,420 emission only and here's the sulphur 2 1330 00:55:38,820 --> 00:55:37,030 and you can do ratios in black and white 1331 00:55:40,950 --> 00:55:38,830 and actually you can find things right 1332 00:55:42,660 --> 00:55:40,960 like here's the the ratio of software to 1333 00:55:45,329 --> 00:55:42,670 2 H alpha and there's kind of three 1334 00:55:47,339 --> 00:55:45,339 three regions that pop out here and it 1335 00:55:50,339 --> 00:55:47,349 turns out here they are in sulfur 2 1336 00:55:51,720 --> 00:55:50,349 there they are NH alpha this was pretty 1337 00:55:53,130 --> 00:55:51,730 confused but these two you can see 1338 00:55:55,230 --> 00:55:53,140 they're about the same brightness and 1339 00:55:57,510 --> 00:55:55,240 sulfur 2 and H alpha is sure enough they 1340 00:55:59,070 --> 00:55:57,520 pop out in the ratio what's really neat 1341 00:56:02,430 --> 00:55:59,080 here is that even though there's all 1342 00:56:04,589 --> 00:56:02,440 this photo ionized gas around the region 1343 00:56:06,410 --> 00:56:04,599 you can still pull out in the ratio that 1344 00:56:09,630 --> 00:56:06,420 there's actually something with enhanced 1345 00:56:11,520 --> 00:56:09,640 ratio buried in that h2 region so 1346 00:56:14,849 --> 00:56:11,530 there's three supernova remnants right 1347 00:56:16,770 --> 00:56:14,859 there for you can look at the O 3 and 1348 00:56:18,810 --> 00:56:16,780 here's the yeah these two actually 1349 00:56:21,150 --> 00:56:18,820 happen to be fairly strong in oxygen 3 1350 00:56:22,920 --> 00:56:21,160 as well compared to H alpha and so let's 1351 00:56:24,000 --> 00:56:22,930 look at the color picture the ones that 1352 00:56:25,770 --> 00:56:24,010 are bright in all three are kind of 1353 00:56:27,140 --> 00:56:25,780 whitish or even a little bluish because 1354 00:56:29,400 --> 00:56:27,150 they've got so much of that oxygen 1355 00:56:31,920 --> 00:56:29,410 emission but we already looked at the 1356 00:56:32,920 --> 00:56:31,930 ratio of the software to da choppah we 1357 00:56:36,280 --> 00:56:32,930 know those are those are 1358 00:56:39,190 --> 00:56:36,290 I this guy does not have very much o3 1359 00:56:41,200 --> 00:56:39,200 and so it comes out looking kind of 1360 00:56:43,180 --> 00:56:41,210 greenish yellow combination of the H 1361 00:56:46,569 --> 00:56:43,190 alpha and the sulphur to so that that 1362 00:56:48,309 --> 00:56:46,579 all kind of hangs together so you say 1363 00:56:51,160 --> 00:56:48,319 wow look at that guy there's a nice 1364 00:56:52,839 --> 00:56:51,170 bright possibly oxygen dominated 1365 00:56:54,790 --> 00:56:52,849 supernova remnant right well it turns 1366 00:56:56,980 --> 00:56:54,800 out that's a planetary nebula in m83 1367 00:56:59,620 --> 00:56:56,990 there's no x-ray emission associated 1368 00:57:05,410 --> 00:56:59,630 with that and so that was a close but no 1369 00:57:06,940 --> 00:57:05,420 cigar in that case so with Hubble what 1370 00:57:09,160 --> 00:57:06,950 we do is we go and we get the size of 1371 00:57:11,079 --> 00:57:09,170 these guys and we actually find some 1372 00:57:13,089 --> 00:57:11,089 additional objects as well because in 1373 00:57:15,040 --> 00:57:13,099 those confused regions at ground-based 1374 00:57:16,750 --> 00:57:15,050 resolution you you you can't find them 1375 00:57:19,839 --> 00:57:16,760 and sometimes the Hubble that they pop 1376 00:57:22,660 --> 00:57:19,849 out so here are seven fields of Hubble 1377 00:57:24,370 --> 00:57:22,670 data with c3 these two green ones were 1378 00:57:25,720 --> 00:57:24,380 actually taken shortly after the last 1379 00:57:27,700 --> 00:57:25,730 servicing mission when the camera was 1380 00:57:29,170 --> 00:57:27,710 first installed and then I came back 1381 00:57:31,630 --> 00:57:29,180 with a team and we got these other five 1382 00:57:33,520 --> 00:57:31,640 fields to kind of round out the coverage 1383 00:57:34,930 --> 00:57:33,530 and get most of the galaxies and we 1384 00:57:36,579 --> 00:57:34,940 looked at it with a bunch of continuum 1385 00:57:38,170 --> 00:57:36,589 filters the star filters and then we 1386 00:57:40,240 --> 00:57:38,180 looked at it with a bunch of these 1387 00:57:43,539 --> 00:57:40,250 emission line filters and played this 1388 00:57:44,799 --> 00:57:43,549 game over that whole galaxy and that's 1389 00:57:49,299 --> 00:57:44,809 what it looks like when you stitch it 1390 00:57:52,420 --> 00:57:49,309 all together and thanks to Zoltan Levay 1391 00:57:54,069 --> 00:57:52,430 here at the Institute for for putting 1392 00:57:56,380 --> 00:57:54,079 that pretty pretty version of it 1393 00:57:58,089 --> 00:57:56,390 together but also thanks to a couple of 1394 00:57:59,980 --> 00:57:58,099 folks here Jennifer Mack and Derek 1395 00:58:02,200 --> 00:57:59,990 hammer who are the ones that figured out 1396 00:58:04,059 --> 00:58:02,210 all the alignments and all the tweaks to 1397 00:58:06,819 --> 00:58:04,069 get it all lined up properly so that 1398 00:58:08,799 --> 00:58:06,829 Zolt could could work as magic on that 1399 00:58:11,020 --> 00:58:08,809 picture and if it looks sort of familiar 1400 00:58:12,880 --> 00:58:11,030 to you but not that familiar to you well 1401 00:58:14,770 --> 00:58:12,890 if you kind of you know cut off this 1402 00:58:16,180 --> 00:58:14,780 little wing out here and just made a 1403 00:58:17,829 --> 00:58:16,190 nice rectangle out of that and turned it 1404 00:58:19,150 --> 00:58:17,839 around sideways you get this nice 1405 00:58:22,380 --> 00:58:19,160 picture of the version that was put out 1406 00:58:25,000 --> 00:58:22,390 as a press release back in January 2014 1407 00:58:26,440 --> 00:58:25,010 that's the same data set scaled a little 1408 00:58:28,780 --> 00:58:26,450 bit differently shows the Stars a little 1409 00:58:30,910 --> 00:58:28,790 bit more dramatically and so forth but 1410 00:58:33,039 --> 00:58:30,920 that's that's a pretty famous Hubble 1411 00:58:36,339 --> 00:58:33,049 picture now and it's the same data set 1412 00:58:37,660 --> 00:58:36,349 that I'll be talking about so it's nice 1413 00:58:39,910 --> 00:58:37,670 to look at the beautiful picture of the 1414 00:58:41,079 --> 00:58:39,920 whole galaxy like this but the real 1415 00:58:42,400 --> 00:58:41,089 power of Hubble is when you start 1416 00:58:45,100 --> 00:58:42,410 zooming into it where you can see the 1417 00:58:47,470 --> 00:58:45,110 details and here are a couple 1418 00:58:48,330 --> 00:58:47,480 this is still a very large area 5,000 1419 00:58:51,250 --> 00:58:48,340 light years across 1420 00:58:53,650 --> 00:58:51,260 showing dust lanes the star formation 1421 00:58:54,940 --> 00:58:53,660 going on in here 1422 00:58:56,350 --> 00:58:54,950 this is a little closer in toward the 1423 00:58:57,970 --> 00:58:56,360 nucleus you can sit tell from the 1424 00:59:00,370 --> 00:58:57,980 background and you could just see the 1425 00:59:02,830 --> 00:59:00,380 tremendous dust lanes and stuff in this 1426 00:59:05,830 --> 00:59:02,840 galaxy but behind that these tremendous 1427 00:59:07,480 --> 00:59:05,840 regions of star formation also going on 1428 00:59:11,650 --> 00:59:07,490 the red regions of course there were 1429 00:59:14,440 --> 00:59:11,660 hydrogen gas is being ionized by the 1430 00:59:16,390 --> 00:59:14,450 Starlight you that only happens for the 1431 00:59:18,610 --> 00:59:16,400 first maybe five million years after a 1432 00:59:20,170 --> 00:59:18,620 burst of star formation maybe ten 1433 00:59:23,110 --> 00:59:20,180 million years on the outside edge and 1434 00:59:24,910 --> 00:59:23,120 you lose that H alpha emission and it 1435 00:59:27,640 --> 00:59:24,920 leaves behind the stars and it might 1436 00:59:30,370 --> 00:59:27,650 look something like this very young star 1437 00:59:31,540 --> 00:59:30,380 forming regions very compact and 1438 00:59:33,070 --> 00:59:31,550 condensed you can see that there's 1439 00:59:35,170 --> 00:59:33,080 bright light in there lots of stars 1440 00:59:36,820 --> 00:59:35,180 there's not even resolved forming but 1441 00:59:39,040 --> 00:59:36,830 they're ionizing the gas around them 1442 00:59:41,290 --> 00:59:39,050 then maybe a little longer along the way 1443 00:59:42,940 --> 00:59:41,300 that that cluster of stars has had 1444 00:59:44,470 --> 00:59:42,950 enough time the stellar winds and a few 1445 00:59:46,630 --> 00:59:44,480 supernovae we have started to blow a 1446 00:59:48,580 --> 00:59:46,640 bubble and they're starting to move that 1447 00:59:51,040 --> 00:59:48,590 stuff away from the site of star 1448 00:59:53,440 --> 00:59:51,050 formation and then maybe you know 50 70 1449 00:59:55,660 --> 00:59:53,450 million years later that material has 1450 00:59:57,850 --> 00:59:55,670 all been dispersed and you're left with 1451 00:59:59,560 --> 00:59:57,860 a cluster of still fairly young stars 1452 01:00:01,930 --> 00:59:59,570 but you see there's a lot more red dots 1453 01:00:03,160 --> 01:00:01,940 in here those are red giant stars some 1454 01:00:05,770 --> 01:00:03,170 of the more massive stars that are now 1455 01:00:08,380 --> 01:00:05,780 started to evolve away from being blue 1456 01:00:09,910 --> 01:00:08,390 and become red giant stars so you can 1457 01:00:11,680 --> 01:00:09,920 actually look at the stellar component 1458 01:00:14,430 --> 01:00:11,690 and understand a lot about what's 1459 01:00:17,050 --> 01:00:14,440 happening with star formation 1460 01:00:19,570 --> 01:00:17,060 interestingly enough we don't find 1461 01:00:22,120 --> 01:00:19,580 supernovae in places like this now it's 1462 01:00:24,040 --> 01:00:22,130 partly because supernova remnants I'm 1463 01:00:26,170 --> 01:00:24,050 sorry we don't find them in regions like 1464 01:00:27,670 --> 01:00:26,180 this because the gas has all been 1465 01:00:29,050 --> 01:00:27,680 cleared out if you blow something up in 1466 01:00:32,260 --> 01:00:29,060 there it just expands out and it doesn't 1467 01:00:34,510 --> 01:00:32,270 hit anything so it never gets bright so 1468 01:00:36,010 --> 01:00:34,520 we no doubt are missing some supernova 1469 01:00:38,590 --> 01:00:36,020 remnants that happened in that in that 1470 01:00:41,140 --> 01:00:38,600 scenario but we tend to find supernova 1471 01:00:44,350 --> 01:00:41,150 remnants in regions around regions like 1472 01:00:46,780 --> 01:00:44,360 this and so for instance here is one 1473 01:00:48,490 --> 01:00:46,790 example and I'll just real briefly tell 1474 01:00:50,380 --> 01:00:48,500 you I'm not going to talk about this in 1475 01:00:52,480 --> 01:00:50,390 any detail but there's an infrared iron 1476 01:00:54,490 --> 01:00:52,490 to line that Hubble Hubble's infrared 1477 01:00:56,279 --> 01:00:54,500 channel can observe that turns out to be 1478 01:00:59,249 --> 01:00:56,289 a very nice diagnostic for 1479 01:01:00,660 --> 01:00:59,259 Jacque heated gas in this case I'm we're 1480 01:01:03,029 --> 01:01:00,670 losing the data up there but you can see 1481 01:01:05,099 --> 01:01:03,039 that this this h2 region that's 1482 01:01:07,380 --> 01:01:05,109 associated up here just is not there at 1483 01:01:10,559 --> 01:01:07,390 all in iron - and this little dot here 1484 01:01:12,539 --> 01:01:10,569 is that's a clue white means it's strong 1485 01:01:14,880 --> 01:01:12,549 in all three of my bands right it's not 1486 01:01:16,469 --> 01:01:14,890 an oxygen dominated guy but it's it's 1487 01:01:18,929 --> 01:01:16,479 bright and all three bands whereas but 1488 01:01:21,539 --> 01:01:18,939 photo wine nice stuff is not and so 1489 01:01:23,279 --> 01:01:21,549 that's a clue and it's very tiny this I 1490 01:01:25,140 --> 01:01:23,289 don't have it marked on here but that 1491 01:01:26,789 --> 01:01:25,150 circle is three arc seconds across so 1492 01:01:28,919 --> 01:01:26,799 that's way below one arc second and 1493 01:01:30,900 --> 01:01:28,929 sighs that little dot there's no star 1494 01:01:33,329 --> 01:01:30,910 there so it's not a subtraction problem 1495 01:01:36,390 --> 01:01:33,339 or anything like that and it's a strong 1496 01:01:40,349 --> 01:01:36,400 soft x-ray source so that is a young 1497 01:01:42,839 --> 01:01:40,359 supernova remnant in m83 doesn't look 1498 01:01:44,939 --> 01:01:42,849 like much but some of them are a little 1499 01:01:48,089 --> 01:01:44,949 more extended here's a little region of 1500 01:01:50,130 --> 01:01:48,099 m83 where there's a five of them in one 1501 01:01:52,259 --> 01:01:50,140 small region and so some of these guys 1502 01:01:54,539 --> 01:01:52,269 this is the emission line band over here 1503 01:01:56,219 --> 01:01:54,549 you can see little shell shapes to these 1504 01:01:58,829 --> 01:01:56,229 guys and whatnot so they're resolved 1505 01:02:00,779 --> 01:01:58,839 this one's a little more funky up here 1506 01:02:02,849 --> 01:02:00,789 all of them are bright and iron which is 1507 01:02:05,009 --> 01:02:02,859 nice to see as a matter of fact here's 1508 01:02:07,769 --> 01:02:05,019 one that's bright an iron that we don't 1509 01:02:09,599 --> 01:02:07,779 see optically we don't see an x-ray and 1510 01:02:12,059 --> 01:02:09,609 that's because it's against this dark 1511 01:02:14,939 --> 01:02:12,069 lane it's probably behind the dust and 1512 01:02:17,130 --> 01:02:14,949 this infrared line actually gets through 1513 01:02:18,660 --> 01:02:17,140 the dust and so we're finding ones that 1514 01:02:20,910 --> 01:02:18,670 we would miss otherwise because we've 1515 01:02:22,529 --> 01:02:20,920 got that iron picture as part of the 1516 01:02:23,969 --> 01:02:22,539 part of the thing but so there's five 1517 01:02:26,429 --> 01:02:23,979 supernova round this one that was not 1518 01:02:28,109 --> 01:02:26,439 known before and here we can now come in 1519 01:02:30,059 --> 01:02:28,119 and measure the sizes of those guys and 1520 01:02:35,219 --> 01:02:30,069 actually use that to understand the 1521 01:02:37,380 --> 01:02:35,229 evolution so I like to show this one 1522 01:02:41,579 --> 01:02:37,390 because this is basically a Cygnus loop 1523 01:02:43,949 --> 01:02:41,589 a big you know 7080 light year across 1524 01:02:47,819 --> 01:02:43,959 object you can see the shell is resolved 1525 01:02:48,900 --> 01:02:47,829 there it's strong at iron - there's you 1526 01:02:50,939 --> 01:02:48,910 know some stars in the region but 1527 01:02:52,859 --> 01:02:50,949 nothing that would contaminate it that 1528 01:02:54,900 --> 01:02:52,869 badly and it's a strong soft x-ray 1529 01:02:57,029 --> 01:02:54,910 source I have a spectrum of this one 1530 01:02:58,410 --> 01:02:57,039 here's the oxygen lines and the and the 1531 01:03:00,329 --> 01:02:58,420 hydrogen line that's in the blue part of 1532 01:03:01,469 --> 01:03:00,339 the spectrum and this is the red part of 1533 01:03:03,719 --> 01:03:01,479 the spectrum you can see the strong 1534 01:03:06,089 --> 01:03:03,729 sulfur lines compared to hydrogen and 1535 01:03:09,390 --> 01:03:06,099 nitrogen just what you like to see and 1536 01:03:09,630 --> 01:03:09,400 again no evidence of broadening above 1537 01:03:14,579 --> 01:03:09,640 the 1538 01:03:19,680 --> 01:03:14,589 that's that's a Cygnus loop in a MIDI 1539 01:03:21,240 --> 01:03:19,690 315 million light-years away so we'll 1540 01:03:22,620 --> 01:03:21,250 come back to the young remnants in a 1541 01:03:24,269 --> 01:03:22,630 minute but I wanted to talk about the 1542 01:03:28,589 --> 01:03:24,279 historical supernova again for a minute 1543 01:03:30,029 --> 01:03:28,599 and in particular this object that 1957 1544 01:03:33,329 --> 01:03:30,039 D so that's a supernova that was 1545 01:03:35,730 --> 01:03:33,339 observed in 1957 so we know how old that 1546 01:03:37,109 --> 01:03:35,740 one is and then this object down here 1547 01:03:40,470 --> 01:03:37,119 that we found that I think is is 1548 01:03:41,970 --> 01:03:40,480 comparable in some ways to was 1549 01:03:43,799 --> 01:03:41,980 definitely a young supernova remnant is 1550 01:03:48,990 --> 01:03:43,809 in some ways it's similar in some ways 1551 01:03:51,150 --> 01:03:49,000 it's different from from 57 D so here's 1552 01:03:53,309 --> 01:03:51,160 a couple of pictures this is the Chandra 1553 01:03:55,950 --> 01:03:53,319 x-ray picture in this case it's a blue 1554 01:03:57,269 --> 01:03:55,960 hard x-ray source which is not typical 1555 01:03:59,460 --> 01:03:57,279 for a supernova in this so usually these 1556 01:04:01,170 --> 01:03:59,470 red colors I might mean it's kind of 1557 01:04:03,690 --> 01:04:01,180 pulsar in it because pulsars have a 1558 01:04:05,519 --> 01:04:03,700 different kind of x-ray spectrum okay at 1559 01:04:07,859 --> 01:04:05,529 ground-based resolution this is what it 1560 01:04:10,410 --> 01:04:07,869 looked like there was a blue dot oxygen 1561 01:04:11,579 --> 01:04:10,420 blue dot and it had some red stuff next 1562 01:04:13,559 --> 01:04:11,589 to it but we really couldn't see what 1563 01:04:15,059 --> 01:04:13,569 was going on and so these two now are 1564 01:04:17,370 --> 01:04:15,069 the Hubble pictures that have been 1565 01:04:19,019 --> 01:04:17,380 zoomed in to that little yellow circle 1566 01:04:20,940 --> 01:04:19,029 up there so we're just looking at that 1567 01:04:25,079 --> 01:04:20,950 region and sure enough what do we see 1568 01:04:26,970 --> 01:04:25,089 blue dominated by oxygen 3 that's the 57 1569 01:04:29,220 --> 01:04:26,980 D and here's some H alpha emission 1570 01:04:31,160 --> 01:04:29,230 that's associated nearby but it is not 1571 01:04:34,559 --> 01:04:31,170 not part of that structure that we see 1572 01:04:36,329 --> 01:04:34,569 there and so that should show broad 1573 01:04:37,680 --> 01:04:36,339 oxygen lines if we're know what we're 1574 01:04:40,829 --> 01:04:37,690 doing and sure enough in the spectra 1575 01:04:42,870 --> 01:04:40,839 here we have the oxygen line and it's 1576 01:04:46,140 --> 01:04:42,880 very very broad interestingly enough 1577 01:04:48,089 --> 01:04:46,150 from 1989 to 2011 when we got the last 1578 01:04:50,220 --> 01:04:48,099 spectrum it's actually faded quite a bit 1579 01:04:52,620 --> 01:04:50,230 but it's still there still broad lines 1580 01:04:53,279 --> 01:04:52,630 it's associated with a little cluster of 1581 01:04:56,700 --> 01:04:53,289 stars 1582 01:04:58,789 --> 01:04:56,710 and we can actually go in and do 1583 01:05:00,990 --> 01:04:58,799 photometry for those stars and 1584 01:05:02,910 --> 01:05:01,000 understand what the most massive stars 1585 01:05:05,099 --> 01:05:02,920 that are in that cluster are and the 1586 01:05:07,529 --> 01:05:05,109 most massive stars are about 17 times 1587 01:05:09,930 --> 01:05:07,539 the mass of the Sun so if this one blew 1588 01:05:11,640 --> 01:05:09,940 up we had to be more massive than that 1589 01:05:13,140 --> 01:05:11,650 because the more massive they are the 1590 01:05:15,749 --> 01:05:13,150 faster they go through their life cycle 1591 01:05:17,309 --> 01:05:15,759 would blow up so it tells us it confirms 1592 01:05:21,930 --> 01:05:17,319 basically there this had to be a massive 1593 01:05:23,370 --> 01:05:21,940 star that that blew up so that's the 57 1594 01:05:26,410 --> 01:05:23,380 D guy 1595 01:05:28,599 --> 01:05:26,420 this other one just take a minute to 1596 01:05:30,910 --> 01:05:28,609 explain these are ground-based pictures 1597 01:05:33,069 --> 01:05:30,920 this is the Hubble pictures zoomed in 1598 01:05:34,809 --> 01:05:33,079 again so the scale changes between those 1599 01:05:36,969 --> 01:05:34,819 two and here's the spectrum of that 1600 01:05:38,829 --> 01:05:36,979 object that we found after after the 1601 01:05:42,459 --> 01:05:38,839 fact the story goes like this 1602 01:05:44,259 --> 01:05:42,469 we we found this object in our 1603 01:05:45,969 --> 01:05:44,269 ground-based data we actually thought 1604 01:05:48,069 --> 01:05:45,979 that there was a larger object and that 1605 01:05:51,789 --> 01:05:48,079 this was a bright not maybe on one side 1606 01:05:53,589 --> 01:05:51,799 of the shell there but when we looked at 1607 01:05:55,120 --> 01:05:53,599 the x-ray data the x-ray data really 1608 01:05:57,219 --> 01:05:55,130 seemed to line up with that bright dot 1609 01:05:58,930 --> 01:05:57,229 up there and so we came in with a 1610 01:06:01,180 --> 01:05:58,940 spectrograph and took a spectrum of that 1611 01:06:04,209 --> 01:06:01,190 dot and this is what it looked like and 1612 01:06:05,739 --> 01:06:04,219 it's very broad lines very high 1613 01:06:08,349 --> 01:06:05,749 expansion velocity so it's a young 1614 01:06:10,719 --> 01:06:08,359 object and the reason we found this with 1615 01:06:12,489 --> 01:06:10,729 our three little filters right I put an 1616 01:06:13,749 --> 01:06:12,499 H off of narrow filter there and a 1617 01:06:15,640 --> 01:06:13,759 software to filter there and it looked 1618 01:06:18,009 --> 01:06:15,650 like it was strong and software to 2h 1619 01:06:19,690 --> 01:06:18,019 alpha and yet it's got this huge feature 1620 01:06:22,269 --> 01:06:19,700 that goes over that entire region of the 1621 01:06:24,489 --> 01:06:22,279 spectrum so I just got lucky on Yellin 1622 01:06:26,079 --> 01:06:24,499 and it does have the oxygen as well so 1623 01:06:28,690 --> 01:06:26,089 we found that it is an interesting 1624 01:06:31,120 --> 01:06:28,700 object but we didn't know that it was 1625 01:06:33,549 --> 01:06:31,130 had this high velocity until we got the 1626 01:06:36,099 --> 01:06:33,559 spectrum of it well now we bring Hubble 1627 01:06:38,259 --> 01:06:36,109 into the picture because Hubble can see 1628 01:06:39,969 --> 01:06:38,269 the bright night and it actually can't 1629 01:06:42,130 --> 01:06:39,979 detect the low surface brightness stuff 1630 01:06:45,609 --> 01:06:42,140 adjacent to it there but here's H alpha 1631 01:06:48,579 --> 01:06:45,619 sulphur 203 just like you know filters 1632 01:06:50,170 --> 01:06:48,589 got gaya and but it's very very tiny 1633 01:06:52,539 --> 01:06:50,180 it's just a dot it looks like a star 1634 01:06:54,670 --> 01:06:52,549 it's not as unresolved it's very tiny 1635 01:06:58,239 --> 01:06:54,680 so from the upper limit on the size of 1636 01:07:00,009 --> 01:06:58,249 the object and the expansion velocity 1637 01:07:01,329 --> 01:07:00,019 that we got from the spectrum we can say 1638 01:07:03,309 --> 01:07:01,339 that it has to be less than a hundred 1639 01:07:06,370 --> 01:07:03,319 years old so this is the one that we 1640 01:07:09,839 --> 01:07:06,380 think is a young supernova remnant that 1641 01:07:12,519 --> 01:07:09,849 where the supernova was not observed 1642 01:07:14,950 --> 01:07:12,529 well okay so we're trying to find these 1643 01:07:16,599 --> 01:07:14,960 young guys and what did we find 1644 01:07:19,420 --> 01:07:16,609 well if we just look at the sizes of 1645 01:07:21,969 --> 01:07:19,430 them the ones that are less than that 35 1646 01:07:25,630 --> 01:07:21,979 light years 11 parsecs forgot to change 1647 01:07:26,950 --> 01:07:25,640 that sorry sighs we found about the 1648 01:07:28,299 --> 01:07:26,960 right number of objects we've got 60 1649 01:07:30,599 --> 01:07:28,309 objects that are about the right size 1650 01:07:34,200 --> 01:07:30,609 that are tiny little supernova remnants 1651 01:07:36,700 --> 01:07:34,210 number of them are x-ray sources as well 1652 01:07:36,940 --> 01:07:36,710 but the only those two objects that I 1653 01:07:42,190 --> 01:07:36,950 show 1654 01:07:44,349 --> 01:07:42,200 minute that looked anything like we 1655 01:07:47,050 --> 01:07:44,359 expected for those ejected dominated 1656 01:07:50,079 --> 01:07:47,060 objects what do the rest of them look 1657 01:07:51,099 --> 01:07:50,089 like well they look like this like kind 1658 01:07:54,160 --> 01:07:51,109 of like that when I showed you a minute 1659 01:07:56,620 --> 01:07:54,170 ago here's another one a tiny little dot 1660 01:07:59,620 --> 01:07:56,630 white right in all three bands not 1661 01:08:02,050 --> 01:07:59,630 dominated by blue by the oxygen strong 1662 01:08:04,290 --> 01:08:02,060 iron source strong soft x-ray source 1663 01:08:07,210 --> 01:08:04,300 there's a few stars in the neighborhood 1664 01:08:10,480 --> 01:08:07,220 fairly blue stars so one of them blew up 1665 01:08:13,810 --> 01:08:10,490 and we take the spectrum no high 1666 01:08:17,170 --> 01:08:13,820 velocities this object is the size of 1667 01:08:20,260 --> 01:08:17,180 Cassiopeia A and yet it has no high 1668 01:08:24,309 --> 01:08:20,270 velocity material and its spectrum looks 1669 01:08:26,979 --> 01:08:24,319 like the Cygnus loop or the other ejecta 1670 01:08:28,510 --> 01:08:26,989 or not the other is M dominated 1671 01:08:31,380 --> 01:08:28,520 inspector the normal supernova resonance 1672 01:08:35,200 --> 01:08:31,390 it does not show evidence of being 1673 01:08:37,690 --> 01:08:35,210 ejected dominated so where are all the 1674 01:08:39,340 --> 01:08:37,700 KSA's this is the third object that has 1675 01:08:40,979 --> 01:08:39,350 some hope of being a castaway we don't 1676 01:08:45,640 --> 01:08:40,989 have a spectrum of this one yet but 1677 01:08:47,769 --> 01:08:45,650 again in oxygen and here's the there's 1678 01:08:49,539 --> 01:08:47,779 no star right there it's right on the 1679 01:08:50,800 --> 01:08:49,549 edge of the bright nucleus of the galaxy 1680 01:08:52,510 --> 01:08:50,810 that right over here is the bright 1681 01:08:55,870 --> 01:08:52,520 bright nucleus of the galaxy so this is 1682 01:08:58,630 --> 01:08:55,880 right on the edge this guy magenta color 1683 01:09:00,459 --> 01:08:58,640 means it's bright an H alpha and o3 it's 1684 01:09:03,099 --> 01:09:00,469 not what we expect exactly but it does 1685 01:09:05,140 --> 01:09:03,109 have the strong L 3 it is very compact 1686 01:09:06,340 --> 01:09:05,150 and there's no star there so I I think 1687 01:09:07,660 --> 01:09:06,350 if we get a spectrum with this that we 1688 01:09:09,490 --> 01:09:07,670 have some hope of maybe seeing high 1689 01:09:12,490 --> 01:09:09,500 velocities and that one so that's the 1690 01:09:14,740 --> 01:09:12,500 third one that's kind of like Cassie but 1691 01:09:16,749 --> 01:09:14,750 we're not finding 60 or hundred of these 1692 01:09:18,340 --> 01:09:16,759 things like we expected even and we 1693 01:09:22,660 --> 01:09:18,350 found the young ones and they don't look 1694 01:09:25,360 --> 01:09:22,670 like this so here's what's going on 1695 01:09:27,220 --> 01:09:25,370 apparently we're seeing we're not seeing 1696 01:09:29,079 --> 01:09:27,230 counterparts to these local ones that 1697 01:09:31,320 --> 01:09:29,089 we've seen where they get this big and 1698 01:09:34,329 --> 01:09:31,330 still show evidence of high velocity and 1699 01:09:38,200 --> 01:09:34,339 ejecta dominated we're seeing things the 1700 01:09:39,880 --> 01:09:38,210 size of Cassie or the crab that already 1701 01:09:42,220 --> 01:09:39,890 looked like the Cygnus loop that have 1702 01:09:43,870 --> 01:09:42,230 evolved beyond the ejecta dominated 1703 01:09:45,729 --> 01:09:43,880 phase into this phase where you're 1704 01:09:49,720 --> 01:09:45,739 looking at shocked interstellar gas 1705 01:09:50,650 --> 01:09:49,730 surrounding the object so the supernova 1706 01:09:53,790 --> 01:09:50,660 remnants and m83 1707 01:09:56,290 --> 01:09:53,800 you're evolving very quickly beyond the 1708 01:10:00,970 --> 01:09:56,300 ejecta phase and into the what's called 1709 01:10:03,670 --> 01:10:00,980 the radiative phase of evolution so we 1710 01:10:05,830 --> 01:10:03,680 didn't find what we expected to find and 1711 01:10:07,510 --> 01:10:05,840 these cards will be on sale in the lobby 1712 01:10:10,930 --> 01:10:07,520 if you wanted I want to send it to me 1713 01:10:12,370 --> 01:10:10,940 after the meeting you know because you 1714 01:10:13,690 --> 01:10:12,380 know sometimes it doesn't work out the 1715 01:10:17,740 --> 01:10:13,700 way you expect it to work out you know 1716 01:10:21,340 --> 01:10:17,750 but so I guess this is probably the most 1717 01:10:26,110 --> 01:10:21,350 most appropriate one for my situation if 1718 01:10:27,970 --> 01:10:26,120 you but when science gives you lemons 1719 01:10:30,040 --> 01:10:27,980 well you make lemonade right and so 1720 01:10:31,510 --> 01:10:30,050 we've learned a lot we've learned some 1721 01:10:33,610 --> 01:10:31,520 really interesting things about this 1722 01:10:35,970 --> 01:10:33,620 galaxy and a couple of things that I 1723 01:10:38,680 --> 01:10:35,980 really didn't highlight to you too much 1724 01:10:42,070 --> 01:10:38,690 I'll do number two here first basically 1725 01:10:44,020 --> 01:10:42,080 m83 has very high chemical element 1726 01:10:46,840 --> 01:10:44,030 abundances even compared to the Milky 1727 01:10:48,610 --> 01:10:46,850 Way we had the small Magellanic Cloud 1728 01:10:52,390 --> 01:10:48,620 the Large Magellanic Cloud the Milky Way 1729 01:10:54,910 --> 01:10:52,400 and m83 the abundances go from about 0.2 1730 01:10:57,960 --> 01:10:54,920 times the sun's abundance to about 0.5 1731 01:11:01,630 --> 01:10:57,970 and the LMC to the Milky Way abundances 1732 01:11:04,000 --> 01:11:01,640 this galaxy has twice solar abundances 1733 01:11:06,640 --> 01:11:04,010 over that entire galaxy and probably 1734 01:11:08,380 --> 01:11:06,650 even higher in the center and I think 1735 01:11:10,870 --> 01:11:08,390 those high abundances are part of the 1736 01:11:12,970 --> 01:11:10,880 story the other part of it is the this 1737 01:11:15,460 --> 01:11:12,980 x-ray data remember shows all this 1738 01:11:18,190 --> 01:11:15,470 diffuse hot gas in the spiral arms 1739 01:11:21,310 --> 01:11:18,200 that's high density high pressure gas in 1740 01:11:23,740 --> 01:11:21,320 the interstellar medium of m83 so let's 1741 01:11:26,110 --> 01:11:23,750 put these two things together hi 1742 01:11:27,730 --> 01:11:26,120 chemical element abundances in a massive 1743 01:11:30,310 --> 01:11:27,740 star allow us to start to have a very 1744 01:11:32,590 --> 01:11:30,320 strong wind that would blow material off 1745 01:11:35,290 --> 01:11:32,600 before the star explodes but if we've 1746 01:11:37,630 --> 01:11:35,300 got a hot high-pressure is M around it 1747 01:11:39,460 --> 01:11:37,640 that stuff can't go very far it hangs 1748 01:11:41,650 --> 01:11:39,470 out right around the outside of where 1749 01:11:43,990 --> 01:11:41,660 the star is going to explode so when the 1750 01:11:45,460 --> 01:11:44,000 star explodes it rams into that stuff 1751 01:11:47,590 --> 01:11:45,470 very quickly and you get a bright 1752 01:11:50,710 --> 01:11:47,600 radiative supernova remnant very quickly 1753 01:11:52,690 --> 01:11:50,720 at a small diameter and so I think 1754 01:11:54,130 --> 01:11:52,700 that's what's tricked us here we're 1755 01:11:57,640 --> 01:11:54,140 finding the young remnants but they're 1756 01:11:59,140 --> 01:11:57,650 not catching them in that ejecta 1757 01:12:01,750 --> 01:11:59,150 dominated phase that we were hoping to 1758 01:12:04,060 --> 01:12:01,760 find and it turns out this is very 1759 01:12:05,680 --> 01:12:04,070 interesting and we're still trying to 1760 01:12:07,899 --> 01:12:05,690 pieced together models and things that 1761 01:12:10,030 --> 01:12:07,909 would that would help us understand 1762 01:12:11,979 --> 01:12:10,040 exactly how that all transpires but 1763 01:12:16,750 --> 01:12:11,989 that's our working model for what's 1764 01:12:19,569 --> 01:12:16,760 going on so worried basically we did 1765 01:12:22,060 --> 01:12:19,579 find a lot of young supernova remnants 1766 01:12:24,790 --> 01:12:22,070 as we expected but we did not find them 1767 01:12:26,890 --> 01:12:24,800 to be in this ejected dominated state 1768 01:12:29,740 --> 01:12:26,900 that we did expect and and I just talked 1769 01:12:31,000 --> 01:12:29,750 about the reasons I hope as we get 1770 01:12:33,040 --> 01:12:31,010 additional spectra for some of these 1771 01:12:35,770 --> 01:12:33,050 candidate objects that we might find a 1772 01:12:37,600 --> 01:12:35,780 couple more of those young objects with 1773 01:12:40,510 --> 01:12:37,610 the very broad lines like that one that 1774 01:12:41,649 --> 01:12:40,520 I showed you but that's not no guarantee 1775 01:12:43,930 --> 01:12:41,659 and it's certainly not going to get us 1776 01:12:47,260 --> 01:12:43,940 up to a hundred of those young objects 1777 01:12:48,850 --> 01:12:47,270 that way so that's it and thanks for 1778 01:12:50,050 --> 01:12:48,860 listening and this is just kind of 1779 01:12:51,910 --> 01:12:50,060 showing you where all the supernova 1780 01:12:54,370 --> 01:12:51,920 remnants are across the galaxy and the 1781 01:12:55,959 --> 01:12:54,380 optical and the x-ray pictures I'd be 1782 01:13:26,500 --> 01:12:55,969 glad to try to answer some questions for 1783 01:13:31,880 --> 01:13:29,660 only sort of indirectly like versus that 1784 01:13:33,200 --> 01:13:31,890 one that I said from the it was seen an 1785 01:13:34,850 --> 01:13:33,210 iron and it wasn't seen in the other 1786 01:13:35,900 --> 01:13:34,860 wavelengths and that iron gets through 1787 01:13:37,670 --> 01:13:35,910 the dust and they're sitting right on 1788 01:13:39,650 --> 01:13:37,680 the dust Lane I know it must be behind 1789 01:13:41,260 --> 01:13:39,660 the dust but other than that I don't 1790 01:13:44,570 --> 01:13:41,270 really have depth into the galaxy 1791 01:13:45,860 --> 01:13:44,580 information that's very small distance 1792 01:13:48,080 --> 01:13:45,870 compared to the distance from us to the 1793 01:13:49,100 --> 01:13:48,090 galaxy so it's just they're essentially 1794 01:13:52,330 --> 01:13:49,110 all at the same distance from my 1795 01:13:56,240 --> 01:13:52,340 perspective but yeah it would be hard to 1796 01:14:06,210 --> 01:13:56,250 pin that down with any certainty yes 1797 01:14:21,939 --> 01:14:08,430 in the actual supernova spectrum are in 1798 01:14:33,379 --> 01:14:25,899 so from the supernova itself basically 1799 01:14:35,719 --> 01:14:33,389 from the ejecta so the spectrum would 1800 01:14:38,509 --> 01:14:35,729 tell me and if the spectrum is emission 1801 01:14:40,520 --> 01:14:38,519 lines I can even get the composition of 1802 01:14:42,350 --> 01:14:40,530 the of the material and so for instance 1803 01:14:44,600 --> 01:14:42,360 an can say that yellow stuff in the 1804 01:14:47,899 --> 01:14:44,610 Hubble picture there was dominated by 1805 01:14:51,589 --> 01:14:47,909 oxygen and sulfur and argon and calcium 1806 01:14:53,000 --> 01:14:51,599 emission no hydrogen no nitrogen that's 1807 01:14:54,350 --> 01:14:53,010 that's a clue right there that it's a 1808 01:14:56,479 --> 01:14:54,360 massive star because that's the kind of 1809 01:14:59,810 --> 01:14:56,489 stuff you get from what's called oxygen 1810 01:15:00,949 --> 01:14:59,820 burning and so forth so you but I could 1811 01:15:01,910 --> 01:15:00,959 look in a different spot and I'd see a 1812 01:15:03,560 --> 01:15:01,920 different spectrum and it would have a 1813 01:15:05,449 --> 01:15:03,570 different composition it came from a 1814 01:15:07,759 --> 01:15:05,459 different layer in the star or whatever 1815 01:15:09,620 --> 01:15:07,769 of course as we go to m83 or longer 1816 01:15:11,719 --> 01:15:09,630 larger distances we can't see the 1817 01:15:14,379 --> 01:15:11,729 individual knots like we see in kasi and 1818 01:15:16,819 --> 01:15:14,389 so you get more of an ensemble spectrum 1819 01:15:18,469 --> 01:15:16,829 instead I if I didn't answer your 1820 01:15:19,129 --> 01:15:18,479 question come up and hold try it don't 1821 01:15:32,810 --> 01:15:19,139 try again 1822 01:15:35,899 --> 01:15:32,820 yes sir it could in principle although 1823 01:15:37,399 --> 01:15:35,909 the vast majority of the core collapse 1824 01:15:39,410 --> 01:15:37,409 remnants now the Crab Nebula is 1825 01:15:41,929 --> 01:15:39,420 different I'll give you that but most of 1826 01:15:44,359 --> 01:15:41,939 them explode there they're flying out 1827 01:15:46,669 --> 01:15:44,369 very rapidly and then eventually they're 1828 01:15:47,540 --> 01:15:46,679 going to slow down with expansion they 1829 01:15:50,299 --> 01:15:47,550 still down with time they don't 1830 01:15:52,009 --> 01:15:50,309 accelerate the Crab Nebula is different 1831 01:15:54,500 --> 01:15:52,019 because it's got that active pulsar in 1832 01:15:56,810 --> 01:15:54,510 there and that pulsar that's spinning 1833 01:16:00,520 --> 01:15:56,820 pulsar you got a one point four solar 1834 01:16:03,169 --> 01:16:00,530 mass object spinning 30 times a second 1835 01:16:04,640 --> 01:16:03,179 mind-boggling so that energy coming off 1836 01:16:06,080 --> 01:16:04,650 of that had particles and magnetic 1837 01:16:08,779 --> 01:16:06,090 fields and whatnot is what energizes 1838 01:16:11,929 --> 01:16:08,789 that blue diffuse gas in the middle of 1839 01:16:13,160 --> 01:16:11,939 the Crab Nebula and that synchrotron is 1840 01:16:15,529 --> 01:16:13,170 called synchrotron emission that 1841 01:16:17,600 --> 01:16:15,539 emission is actually pushing out on the 1842 01:16:19,270 --> 01:16:17,610 filaments and accelerating them so 1843 01:16:21,290 --> 01:16:19,280 they're actually going faster with time 1844 01:16:23,120 --> 01:16:21,300 even though it's only going 1,800 1845 01:16:25,279 --> 01:16:23,130 kilometers per second compared to 10,000 1846 01:16:27,169 --> 01:16:25,289 that was a must have been a low-energy 1847 01:16:29,029 --> 01:16:27,179 explosion or something that just didn't 1848 01:16:31,640 --> 01:16:29,039 start it off that fast but it's actually 1849 01:16:33,739 --> 01:16:31,650 being accelerated yeah now but most of 1850 01:16:34,760 --> 01:16:33,749 them it's just boom it goes off they fly 1851 01:16:38,780 --> 01:16:34,770 out and eventually 1852 01:16:40,820 --> 01:16:38,790 slow down yeah yeah so for cafe for 1853 01:16:43,160 --> 01:16:40,830 instance interesting enough can't say 1854 01:16:45,530 --> 01:16:43,170 this young is 340 plus or minus a few 1855 01:16:49,070 --> 01:16:45,540 year object in our own galaxy the 1856 01:16:52,250 --> 01:16:49,080 supernova was not seen in 16 roughly 1857 01:16:54,710 --> 01:16:52,260 1680 and here we've got the Chinese have 1858 01:16:58,520 --> 01:16:54,720 observations to go back to yellow BC 1859 01:17:00,290 --> 01:16:58,530 times right and and as somehow in 1680 1860 01:17:01,640 --> 01:17:00,300 even with European observers and it was 1861 01:17:02,150 --> 01:17:01,650 placed well in the northern sky and 1862 01:17:04,820 --> 01:17:02,160 everything like that 1863 01:17:07,940 --> 01:17:04,830 they didn't see the supernova now maybe 1864 01:17:10,040 --> 01:17:07,950 it was a sub luminous supernova but even 1865 01:17:12,290 --> 01:17:10,050 so it's in our galaxy it shouldn't it 1866 01:17:14,450 --> 01:17:12,300 should have been easily visible probably 1867 01:17:16,400 --> 01:17:14,460 but to get the age of it they look at 1868 01:17:19,990 --> 01:17:16,410 the fastest material they see flying out 1869 01:17:22,940 --> 01:17:20,000 right now assume that's unda celebrated 1870 01:17:24,110 --> 01:17:22,950 and look at its proper motion and then 1871 01:17:25,960 --> 01:17:24,120 they take that backwards in time and 1872 01:17:35,420 --> 01:17:25,970 that's how they came up with the 1680 1873 01:17:37,520 --> 01:17:35,430 number for that one you know that is 1874 01:17:41,060 --> 01:17:37,530 difficult to determine supernova 1875 01:17:43,460 --> 01:17:41,070 remnants from type 1a supernovae versus 1876 01:17:45,140 --> 01:17:43,470 core-collapse how does that uncertainty 1877 01:17:48,200 --> 01:17:45,150 play into the star formation 1878 01:17:49,910 --> 01:17:48,210 calculations or other information so the 1879 01:17:51,500 --> 01:17:49,920 idea is you were looking at it this you 1880 01:17:52,970 --> 01:17:51,510 showed a lot in the spectra that you're 1881 01:17:55,040 --> 01:17:52,980 you know almost I almost sort of a 1882 01:17:57,800 --> 01:17:55,050 case-by-case basis you have to figure 1883 01:17:59,870 --> 01:17:57,810 out what the progenitor was right how 1884 01:18:01,490 --> 01:17:59,880 does that play into the star formation 1885 01:18:04,490 --> 01:18:01,500 rate that calculations what I do with 1886 01:18:07,010 --> 01:18:04,500 this yeah so it's an area of ongoing 1887 01:18:08,570 --> 01:18:07,020 research basically once the objects have 1888 01:18:10,580 --> 01:18:08,580 expanded to the point that they're just 1889 01:18:12,650 --> 01:18:10,590 shocking the interstellar gas around 1890 01:18:13,850 --> 01:18:12,660 them and expanding you can't tell what 1891 01:18:16,280 --> 01:18:13,860 kind of a star it was that blew up 1892 01:18:19,970 --> 01:18:16,290 without knowledge of the supernova 1893 01:18:23,030 --> 01:18:19,980 itself but you can play some games you 1894 01:18:24,800 --> 01:18:23,040 can say wow here's the supernova remnant 1895 01:18:27,590 --> 01:18:24,810 it's right next to this big cluster of 1896 01:18:29,540 --> 01:18:27,600 blue blue massive stars probably a core 1897 01:18:31,310 --> 01:18:29,550 collapse even if you didn't see the 1898 01:18:33,260 --> 01:18:31,320 supernova right and then taking it the 1899 01:18:34,670 --> 01:18:33,270 other way when you see a supernova room 1900 01:18:38,750 --> 01:18:34,680 that it's kind of out in the middle of 1901 01:18:40,310 --> 01:18:38,760 nowhere and there's no young star 1902 01:18:42,850 --> 01:18:40,320 cluster around or anything like that you 1903 01:18:45,410 --> 01:18:42,860 could say that was probably a type 1a 1904 01:18:46,850 --> 01:18:45,420 exploding white dwarf type 1a 1905 01:18:49,490 --> 01:18:46,860 supernovae there's different types of 1906 01:18:51,290 --> 01:18:49,500 supernovae and so you could look at an 1907 01:18:54,140 --> 01:18:51,300 ensemble in a galaxy like this Medina 1908 01:18:55,520 --> 01:18:54,150 1031 in particular and they try to make 1909 01:18:57,290 --> 01:18:55,530 those correlations and try to look at 1910 01:18:58,729 --> 01:18:57,300 those subsets separate from each other 1911 01:19:01,339 --> 01:18:58,739 and see if they can find correlations 1912 01:19:02,689 --> 01:19:01,349 and stuff like that but it's it's an 1913 01:19:06,500 --> 01:19:02,699 uncertain business if you haven't seen 1914 01:19:12,859 --> 01:19:06,510 the supernova yeah you know other 1915 01:19:19,189 --> 01:19:12,869 questions i warm down I check online to 1916 01:19:21,890 --> 01:19:20,570 yeah you've already answered the 1917 01:19:52,650 --> 01:19:21,900 question about how you determine the age 1918 01:19:58,300 --> 01:19:55,600 well they're mostly in the comments are 1919 01:20:00,700 --> 01:19:58,310 mostly ice they have an admixture it's 1920 01:20:02,620 --> 01:20:00,710 just basically whatever came together to 1921 01:20:03,850 --> 01:20:02,630 make the object right so what depending 1922 01:20:05,890 --> 01:20:03,860 on what part of the solar system they 1923 01:20:07,210 --> 01:20:05,900 formed and what the materials were 1924 01:20:11,680 --> 01:20:07,220 around when they form they have 1925 01:20:13,660 --> 01:20:11,690 different admixture of ices versus rocky 1926 01:20:16,450 --> 01:20:13,670 dusty stuff you know there's a lot we 1927 01:20:17,890 --> 01:20:16,460 look at your stars that are forming 1928 01:20:20,470 --> 01:20:17,900 planets right now and they have discs of 1929 01:20:22,480 --> 01:20:20,480 dust and gas around them that's the 1930 01:20:24,070 --> 01:20:22,490 stuff that some of which ends up making 1931 01:20:26,380 --> 01:20:24,080 comments right and so it's it's a 1932 01:20:27,820 --> 01:20:26,390 mixture of gas and dust and you just get 1933 01:20:30,880 --> 01:20:27,830 different comics will have a slightly 1934 01:20:32,290 --> 01:20:30,890 different mixture of those temperature 1935 01:20:34,000 --> 01:20:32,300 would be a big factor yeah right well 1936 01:20:35,860 --> 01:20:34,010 also you recognize that if you examine 1937 01:20:39,400 --> 01:20:35,870 the surface of a comet you're not going 1938 01:20:42,220 --> 01:20:39,410 to find a lot of fresh ice because as it 1939 01:20:44,830 --> 01:20:42,230 goes goes past those volatiles will go 1940 01:20:47,050 --> 01:20:44,840 away on the surface of the comet so at 1941 01:20:49,360 --> 01:20:47,060 the part of the idea the Deep Impact 1942 01:20:52,120 --> 01:20:49,370 mission was to try and look at the 1943 01:20:55,080 --> 01:20:52,130 subsurface material that spews out when 1944 01:20:59,280 --> 01:20:55,090 we basically through a washing machine 1945 01:21:08,410 --> 01:20:59,290 into a comet at 25,000 miles an hour by 1946 01:21:09,430 --> 01:21:08,420 my analogy yeah okay is there somebody 1947 01:21:11,320 --> 01:21:09,440 from the Maryland Space Grant 1948 01:21:14,170 --> 01:21:11,330 Observatory here to take people across 1949 01:21:17,830 --> 01:21:14,180 the street I do not see that person I 1950 01:21:19,990 --> 01:21:17,840 will talk to them next month and make 1951 01:21:23,620 --> 01:21:20,000 sure that they either show up or let me 1952 01:21:26,260 --> 01:21:23,630 know with an email let's see next month 1953 01:21:31,090 --> 01:21:26,270 we have Toby mariage talking about the 1954 01:21:34,300 --> 01:21:31,100 cosmology large angular scale survey and 1955 01:21:35,800 --> 01:21:34,310 that will be on November 1st all right 1956 01:21:39,040 --> 01:21:35,810 that is a week before Election Day so 1957 01:21:40,710 --> 01:21:39,050 you know you can won't have to deal with 1958 01:21:43,180 --> 01:21:40,720 any of the election stuff that night 1959 01:21:44,740 --> 01:21:43,190 hopefully we maybe will have to deal 1960 01:21:46,960 --> 01:21:44,750 with the a the oriole so I wouldn't 1961 01:21:48,340 --> 01:21:46,970 wouldn't mind it that that happened but 1962 01:21:57,380 --> 01:21:48,350 ladies and gentlemen let's give Bill one 1963 01:22:05,070 --> 01:22:03,000 did anybody leave a thermal cup the 1964 01:22:08,280 --> 01:22:05,080 facilities found this two months ago I 1965 01:22:12,780 --> 01:22:08,290 think in August they handed it to me