1 00:00:03,750 --> 00:00:01,829 [Music] 2 00:00:05,349 --> 00:00:03,760 nasa's jet propulsion laboratory 3 00:00:07,990 --> 00:00:05,359 presents 4 00:00:10,070 --> 00:00:08,000 the von carmen lecture a series of talks 5 00:00:13,350 --> 00:00:10,080 by scientists and engineers who are 6 00:00:18,350 --> 00:00:13,360 exploring our planet our solar system 7 00:00:25,269 --> 00:00:22,790 [Music] 8 00:00:26,790 --> 00:00:25,279 good evening everybody 9 00:00:28,550 --> 00:00:26,800 thank you for joining us tonight my name 10 00:00:30,710 --> 00:00:28,560 is mark razzie from the public services 11 00:00:32,229 --> 00:00:30,720 office at jpl and again want to thank 12 00:00:34,709 --> 00:00:32,239 you so much for joining us for this 13 00:00:35,670 --> 00:00:34,719 edition of the von carmen series 14 00:00:37,190 --> 00:00:35,680 tonight 15 00:00:39,670 --> 00:00:37,200 we're going to explore the infrared 16 00:00:41,430 --> 00:00:39,680 spectrum or at least some of it 17 00:00:43,830 --> 00:00:41,440 now william herschel first discovered 18 00:00:46,790 --> 00:00:43,840 the infrared in 1800 but it wasn't until 19 00:00:49,029 --> 00:00:46,800 the mid-20th century that real research 20 00:00:51,270 --> 00:00:49,039 into that part of the spectrum began but 21 00:00:53,270 --> 00:00:51,280 when it did it began in earnest there 22 00:00:55,189 --> 00:00:53,280 have been many instruments telescopes 23 00:00:57,430 --> 00:00:55,199 and spacecraft that have all worked to 24 00:00:59,110 --> 00:00:57,440 reveal mysteries hidden in the infrared 25 00:01:00,310 --> 00:00:59,120 but there are still plenty of unanswered 26 00:01:03,270 --> 00:01:00,320 questions 27 00:01:05,109 --> 00:01:03,280 tonight our guests who are but two 28 00:01:07,030 --> 00:01:05,119 of very many people working on these 29 00:01:09,030 --> 00:01:07,040 projects by the way are going to talk 30 00:01:11,030 --> 00:01:09,040 about two upcoming missions that hope to 31 00:01:13,910 --> 00:01:11,040 deepen our understanding of our universe 32 00:01:16,310 --> 00:01:13,920 by continuing to delve into the infrared 33 00:01:18,550 --> 00:01:16,320 helping me out tonight with the q a is 34 00:01:22,710 --> 00:01:18,560 our co-host jpl public outreach 35 00:01:24,870 --> 00:01:22,720 specialist caitlin soares hi caitlin 36 00:01:26,550 --> 00:01:24,880 hello and welcome everyone as mark 37 00:01:29,429 --> 00:01:26,560 mentioned my name is caitlin and i work 38 00:01:31,270 --> 00:01:29,439 in public outreach at jpl we have a 39 00:01:32,630 --> 00:01:31,280 fascinating program for you tonight and 40 00:01:35,590 --> 00:01:32,640 we want you to be involved in the 41 00:01:37,350 --> 00:01:35,600 conversation so please ask questions in 42 00:01:38,789 --> 00:01:37,360 the chat and we'll try to address as 43 00:01:40,870 --> 00:01:38,799 many of them as possible tonight 44 00:01:42,789 --> 00:01:40,880 throughout our discussion if you don't 45 00:01:44,230 --> 00:01:42,799 see the chat for some reason please 46 00:01:46,069 --> 00:01:44,240 refresh your browser and it should 47 00:01:47,510 --> 00:01:46,079 appear and i'll turn it back over to 48 00:01:50,069 --> 00:01:47,520 mark now so he can introduce our 49 00:01:51,990 --> 00:01:50,079 brilliant speakers for tonight's program 50 00:01:55,109 --> 00:01:52,000 thank you very much caitlin so our 51 00:01:57,590 --> 00:01:55,119 guests tonight are dr dita markovic who 52 00:01:59,990 --> 00:01:57,600 is a research scientist at jpl 53 00:02:01,990 --> 00:02:00,000 working on the euclid mission and dr 54 00:02:04,389 --> 00:02:02,000 phil corngut who is a research scientist 55 00:02:06,709 --> 00:02:04,399 at caltech and the instrument scientist 56 00:02:08,790 --> 00:02:06,719 on the spherex mission good evening my 57 00:02:11,830 --> 00:02:08,800 friends how are you guys 58 00:02:14,550 --> 00:02:11,840 all right it's super happy to be here 59 00:02:15,830 --> 00:02:14,560 thanks our pleasure so phil to set the 60 00:02:17,350 --> 00:02:15,840 stage 61 00:02:18,550 --> 00:02:17,360 uh would you be so kind to give us a 62 00:02:21,430 --> 00:02:18,560 little bit of a primer on the 63 00:02:23,990 --> 00:02:21,440 electromagnetic spectrum 64 00:02:26,390 --> 00:02:24,000 sure be happy to all right well uh when 65 00:02:28,470 --> 00:02:26,400 you think about fundamental measurements 66 00:02:29,910 --> 00:02:28,480 in astronomy there's really one 67 00:02:33,430 --> 00:02:29,920 observable we're talking about and 68 00:02:35,750 --> 00:02:33,440 that's electromagnetic radiation now 69 00:02:37,670 --> 00:02:35,760 you're more familiar with that term by 70 00:02:38,710 --> 00:02:37,680 its colloquial term 71 00:02:39,830 --> 00:02:38,720 light 72 00:02:42,390 --> 00:02:39,840 and 73 00:02:44,790 --> 00:02:42,400 all the signals that we're measuring 74 00:02:46,550 --> 00:02:44,800 from the gamma ray through x-ray and all 75 00:02:48,869 --> 00:02:46,560 the way to the radio those are all just 76 00:02:50,949 --> 00:02:48,879 different flavors of light and the 77 00:02:53,190 --> 00:02:50,959 parameter which which governs that 78 00:02:54,710 --> 00:02:53,200 flavor is what we call wavelength so 79 00:02:57,030 --> 00:02:54,720 what you're looking at here in this in 80 00:02:58,790 --> 00:02:57,040 this plot is the electromagnetic 81 00:03:00,070 --> 00:02:58,800 spectrum that is accessible to 82 00:03:02,630 --> 00:03:00,080 astronomers 83 00:03:05,830 --> 00:03:02,640 that x-axis there in wavelength is a 84 00:03:07,190 --> 00:03:05,840 logarithmic scale and it spans 15 orders 85 00:03:09,430 --> 00:03:07,200 of magnitude 86 00:03:12,550 --> 00:03:09,440 so that's literally a factor of a 87 00:03:14,070 --> 00:03:12,560 million times a billion in the available 88 00:03:15,589 --> 00:03:14,080 light that's out there 89 00:03:18,630 --> 00:03:15,599 the way you think about those different 90 00:03:20,630 --> 00:03:18,640 flavors in in terms of your real world 91 00:03:23,509 --> 00:03:20,640 is is in color 92 00:03:25,110 --> 00:03:23,519 except uh it's far outreaching from what 93 00:03:26,550 --> 00:03:25,120 your eyeballs are used to if we go to 94 00:03:29,350 --> 00:03:26,560 the next slide 95 00:03:30,550 --> 00:03:29,360 you can see in context the optical which 96 00:03:32,070 --> 00:03:30,560 is every 97 00:03:34,869 --> 00:03:32,080 you know piece of light that you've ever 98 00:03:37,190 --> 00:03:34,879 seen in your life from blue to red which 99 00:03:39,990 --> 00:03:37,200 spans only about you know less than a 100 00:03:42,710 --> 00:03:40,000 factor of two in wavelength so that's a 101 00:03:44,789 --> 00:03:42,720 pretty wild concept to to think about 102 00:03:46,470 --> 00:03:44,799 there's a million billion colors out 103 00:03:48,070 --> 00:03:46,480 there you could see 104 00:03:49,830 --> 00:03:48,080 you know just over a factor of two of 105 00:03:51,910 --> 00:03:49,840 them so there's all sorts of uh 106 00:03:53,670 --> 00:03:51,920 observables which which 107 00:03:55,350 --> 00:03:53,680 can trace all sorts of stuff from 108 00:03:57,589 --> 00:03:55,360 astronomical objects 109 00:03:59,509 --> 00:03:57,599 it's not a surprise why your eyeballs 110 00:04:01,350 --> 00:03:59,519 work in that wavelength range called the 111 00:04:02,949 --> 00:04:01,360 optical if you click on the next slide 112 00:04:03,990 --> 00:04:02,959 we'll show the spectrum the emission 113 00:04:06,229 --> 00:04:04,000 spectrum 114 00:04:08,309 --> 00:04:06,239 of your very favorite source or at least 115 00:04:10,149 --> 00:04:08,319 the one that is most common 116 00:04:13,509 --> 00:04:10,159 here on earth which is 117 00:04:15,190 --> 00:04:13,519 the star that is our hometown or the sun 118 00:04:18,390 --> 00:04:15,200 which is about 119 00:04:20,629 --> 00:04:18,400 on the order of 5700 degrees kelvin and 120 00:04:22,230 --> 00:04:20,639 its spectrum looks like that which peaks 121 00:04:23,990 --> 00:04:22,240 in the optical 122 00:04:26,230 --> 00:04:24,000 on the next slide we'll kind of zoom in 123 00:04:28,390 --> 00:04:26,240 on on that neighborhood 124 00:04:30,469 --> 00:04:28,400 and uh you know the the peak of the sun 125 00:04:33,110 --> 00:04:30,479 which is right there around green at a 126 00:04:35,909 --> 00:04:33,120 few hundred nanometers wavelength 127 00:04:38,070 --> 00:04:35,919 just redder than red so at longer 128 00:04:40,070 --> 00:04:38,080 wavelengths than your eyeballs work at 129 00:04:42,070 --> 00:04:40,080 is the near infrared and that's that's 130 00:04:43,510 --> 00:04:42,080 the the region that we're interested in 131 00:04:46,150 --> 00:04:43,520 discussing today 132 00:04:47,830 --> 00:04:46,160 and there's all sorts of interesting uh 133 00:04:50,070 --> 00:04:47,840 sources out there 134 00:04:52,469 --> 00:04:50,080 nominally things which are emitting 135 00:04:54,870 --> 00:04:52,479 thermally in the infrared so things that 136 00:04:56,950 --> 00:04:54,880 are not quite as hot as the sun that go 137 00:04:59,110 --> 00:04:56,960 down to thousands to even you know 138 00:05:01,990 --> 00:04:59,120 hundreds of degrees kelvin 139 00:05:04,550 --> 00:05:02,000 now there's a problem while with uh you 140 00:05:06,710 --> 00:05:04,560 know doing that kind of observation here 141 00:05:08,390 --> 00:05:06,720 on our hometown of the earth if you 142 00:05:10,469 --> 00:05:08,400 click to the next slide 143 00:05:12,310 --> 00:05:10,479 you can see what our 144 00:05:14,230 --> 00:05:12,320 atmosphere does so 145 00:05:17,029 --> 00:05:14,240 while earth's atmosphere is great for 146 00:05:19,350 --> 00:05:17,039 things like breathing and living on it's 147 00:05:20,950 --> 00:05:19,360 not so great for looking through so all 148 00:05:22,870 --> 00:05:20,960 of those magenta lines that you're 149 00:05:24,870 --> 00:05:22,880 seeing there that's absorption features 150 00:05:27,670 --> 00:05:24,880 in our earth's atmosphere 151 00:05:29,430 --> 00:05:27,680 so um you know while air looks clear to 152 00:05:31,270 --> 00:05:29,440 you in the optical if you look in the 153 00:05:33,110 --> 00:05:31,280 near infrared it's not really clear at 154 00:05:35,749 --> 00:05:33,120 all there's all sorts of stuff uh 155 00:05:37,670 --> 00:05:35,759 absorbing not to mention that everything 156 00:05:39,189 --> 00:05:37,680 you know that's here on earth that's uh 157 00:05:40,710 --> 00:05:39,199 you know kind of room temperature is 158 00:05:43,189 --> 00:05:40,720 actually glowing 159 00:05:44,469 --> 00:05:43,199 in in light and emitting so it really 160 00:05:47,430 --> 00:05:44,479 makes sense 161 00:05:50,070 --> 00:05:47,440 when you're doing astronomy in the near 162 00:05:53,110 --> 00:05:50,080 infrared to get off of this planet and 163 00:05:53,909 --> 00:05:53,120 go up into space 164 00:05:59,909 --> 00:05:53,919 so 165 00:06:02,309 --> 00:05:59,919 astronomy 166 00:06:03,909 --> 00:06:02,319 yeah i'm happy to do that so i guess 167 00:06:06,790 --> 00:06:03,919 what i should say first is that 168 00:06:09,189 --> 00:06:06,800 astronomy is kind of like detective work 169 00:06:10,870 --> 00:06:09,199 it's not quite like other science where 170 00:06:12,390 --> 00:06:10,880 you can you know put something in a lab 171 00:06:14,790 --> 00:06:12,400 and poke it and see what happens and 172 00:06:15,990 --> 00:06:14,800 then you know figure out the laws of 173 00:06:17,510 --> 00:06:16,000 nature that way 174 00:06:18,790 --> 00:06:17,520 in astronomy 175 00:06:21,029 --> 00:06:18,800 the things that we're interested in are 176 00:06:22,950 --> 00:06:21,039 really really far away so all we can do 177 00:06:25,029 --> 00:06:22,960 is kind of sit here and hope that 178 00:06:27,029 --> 00:06:25,039 information will you know on its own 179 00:06:29,270 --> 00:06:27,039 come to reach us and so things that we 180 00:06:31,110 --> 00:06:29,280 observe you know we look at stars and if 181 00:06:32,390 --> 00:06:31,120 you're cosmologists like phil and i you 182 00:06:34,870 --> 00:06:32,400 look at things that are much much 183 00:06:37,110 --> 00:06:34,880 further away than stars like galaxies 184 00:06:38,870 --> 00:06:37,120 and so what we do is we sit here and we 185 00:06:40,629 --> 00:06:38,880 collect the information that's coming to 186 00:06:43,029 --> 00:06:40,639 us from from those galaxies and the most 187 00:06:45,029 --> 00:06:43,039 common way this information reaches us 188 00:06:47,270 --> 00:06:45,039 is through light and we're talking about 189 00:06:49,029 --> 00:06:47,280 the electromagnetic spectrum today so so 190 00:06:51,350 --> 00:06:49,039 that's of course uh what i'm talking 191 00:06:53,029 --> 00:06:51,360 about here and so so this light comes 192 00:06:55,110 --> 00:06:53,039 from these really distant galaxies to us 193 00:06:57,909 --> 00:06:55,120 and we built these huge collectors of 194 00:06:59,990 --> 00:06:57,919 light or telescopes to to capture it and 195 00:07:01,270 --> 00:07:00,000 then of course we examine all the 196 00:07:02,790 --> 00:07:01,280 information we try to get all the 197 00:07:04,469 --> 00:07:02,800 information that's in this light and one 198 00:07:06,150 --> 00:07:04,479 of the things that we do is we break it 199 00:07:07,830 --> 00:07:06,160 up into its component wavelengths or 200 00:07:09,350 --> 00:07:07,840 frequencies or energies 201 00:07:11,350 --> 00:07:09,360 which is basically the spectrum that 202 00:07:14,070 --> 00:07:11,360 phil has been telling you about and 203 00:07:15,990 --> 00:07:14,080 these spectra they contain 204 00:07:19,350 --> 00:07:16,000 basically a fingerprint a really 205 00:07:21,510 --> 00:07:19,360 specific pattern that tells us a lot 206 00:07:23,189 --> 00:07:21,520 about the chemical properties the 207 00:07:25,350 --> 00:07:23,199 thermal properties and the kinematic 208 00:07:27,029 --> 00:07:25,360 properties of the thing that's emitting 209 00:07:29,749 --> 00:07:27,039 that light so the light source so the 210 00:07:31,909 --> 00:07:29,759 properties of the stars and the galaxies 211 00:07:34,710 --> 00:07:31,919 and so we can have you know we can have 212 00:07:36,309 --> 00:07:34,720 like uh very small ranges in in in 213 00:07:38,070 --> 00:07:36,319 wavelength or frequency where there's a 214 00:07:40,390 --> 00:07:38,080 bit of extra light in there and those 215 00:07:41,830 --> 00:07:40,400 are called emission lines or we can have 216 00:07:43,749 --> 00:07:41,840 part of the spectrum where there's a 217 00:07:45,510 --> 00:07:43,759 little bit less light so if you if you 218 00:07:47,510 --> 00:07:45,520 show the next picture you can see um 219 00:07:49,830 --> 00:07:47,520 i've sort of made a little a picture 220 00:07:51,430 --> 00:07:49,840 that shows a kind of a pattern of these 221 00:07:52,710 --> 00:07:51,440 uh absorption lines where there's a 222 00:07:54,150 --> 00:07:52,720 little bit less light and there's an 223 00:07:56,230 --> 00:07:54,160 emission light with a little bit more 224 00:07:58,469 --> 00:07:56,240 light and this is specific pattern we 225 00:08:00,790 --> 00:07:58,479 can that we can understand really well 226 00:08:03,029 --> 00:08:00,800 because it the exact pattern of the 227 00:08:04,629 --> 00:08:03,039 emission absorption lines uh comes out 228 00:08:06,469 --> 00:08:04,639 of quantum physics and we can play 229 00:08:08,070 --> 00:08:06,479 around with this in the lab and and 230 00:08:10,150 --> 00:08:08,080 actually calculate exactly what these 231 00:08:11,670 --> 00:08:10,160 lights might appear might appear for you 232 00:08:13,510 --> 00:08:11,680 know in different if you have different 233 00:08:14,790 --> 00:08:13,520 types of stuff that's emitting the light 234 00:08:16,070 --> 00:08:14,800 the light different gases at different 235 00:08:18,070 --> 00:08:16,080 temperatures 236 00:08:19,830 --> 00:08:18,080 and what's also really cool is that 237 00:08:21,270 --> 00:08:19,840 something really interesting happens to 238 00:08:23,990 --> 00:08:21,280 this pattern 239 00:08:26,070 --> 00:08:24,000 and uh if if there's some kind of motion 240 00:08:28,150 --> 00:08:26,080 of the emitter of this light so let me 241 00:08:29,589 --> 00:08:28,160 first um tell you about the doppler 242 00:08:31,350 --> 00:08:29,599 effect so you might have heard of it 243 00:08:33,909 --> 00:08:31,360 before and it's an effect that happens 244 00:08:35,029 --> 00:08:33,919 in sound um and it's it's i'm sure 245 00:08:36,709 --> 00:08:35,039 you've all even if you don't know the 246 00:08:39,269 --> 00:08:36,719 expression doppler effect you would have 247 00:08:40,949 --> 00:08:39,279 experienced it because an example of it 248 00:08:43,509 --> 00:08:40,959 is if you have an emergency vehicle that 249 00:08:45,269 --> 00:08:43,519 has a siren that's moving towards you 250 00:08:47,750 --> 00:08:45,279 and if the emergency vehicle is moving 251 00:08:49,750 --> 00:08:47,760 towards you it's as if as if the waves 252 00:08:52,310 --> 00:08:49,760 the sound waves are getting squished 253 00:08:54,389 --> 00:08:52,320 together and so the pitch of the siren 254 00:08:56,310 --> 00:08:54,399 you know is higher than usual 255 00:08:58,710 --> 00:08:56,320 and if it's if the emergency vehicle is 256 00:09:00,550 --> 00:08:58,720 hopefully moving away from you um then 257 00:09:02,870 --> 00:09:00,560 it's as if the sound waves get stretched 258 00:09:04,949 --> 00:09:02,880 out and the pitch falls so the siren as 259 00:09:06,949 --> 00:09:04,959 it approaches you it is high pitched and 260 00:09:09,110 --> 00:09:06,959 then as it moves past you and goes away 261 00:09:10,710 --> 00:09:09,120 from you the pitch falls and something 262 00:09:12,949 --> 00:09:10,720 kind of similar happens in light and 263 00:09:14,710 --> 00:09:12,959 it's really interesting but the the big 264 00:09:16,630 --> 00:09:14,720 difference is uh one of the big 265 00:09:18,949 --> 00:09:16,640 differences is that the thing that is 266 00:09:21,269 --> 00:09:18,959 emitting this light needs to be moving 267 00:09:23,110 --> 00:09:21,279 with respect to the observer so its 268 00:09:24,790 --> 00:09:23,120 speed with respect to you has to be a 269 00:09:27,269 --> 00:09:24,800 lot higher than of that emergency 270 00:09:28,949 --> 00:09:27,279 vehicle in fact this light emitter needs 271 00:09:30,630 --> 00:09:28,959 to be traveling at a significant 272 00:09:32,470 --> 00:09:30,640 fraction of the speed of light so you 273 00:09:34,790 --> 00:09:32,480 might say close to the speed of light 274 00:09:36,870 --> 00:09:34,800 for this kind of shifting effect to be 275 00:09:38,870 --> 00:09:36,880 observable so what happens is if you 276 00:09:41,750 --> 00:09:38,880 have a distant galaxy that is for some 277 00:09:43,350 --> 00:09:41,760 mysterious reason moving away from you 278 00:09:45,350 --> 00:09:43,360 the wavelength it's as if the wavelength 279 00:09:49,430 --> 00:09:45,360 of light gets stretched out 280 00:09:51,509 --> 00:09:49,440 um it gets red-shifted and uh so the the 281 00:09:52,870 --> 00:09:51,519 the any the pattern 282 00:09:55,269 --> 00:09:52,880 moves towards the red part of the 283 00:09:57,509 --> 00:09:55,279 spectrum and if the galaxy was moving 284 00:09:59,509 --> 00:09:57,519 towards you the light would get blue 285 00:10:01,910 --> 00:09:59,519 shifted so this specific pattern this 286 00:10:04,389 --> 00:10:01,920 fingerprint that we can understand moves 287 00:10:07,110 --> 00:10:04,399 towards the blue and so you can measure 288 00:10:08,550 --> 00:10:07,120 this red shift or blue shift and about a 289 00:10:11,030 --> 00:10:08,560 hundred years ago there was somebody 290 00:10:12,949 --> 00:10:11,040 called vesto schleifer who tried to 291 00:10:15,509 --> 00:10:12,959 measure uh you know he looked at a bunch 292 00:10:17,269 --> 00:10:15,519 of things that he called nebulae but we 293 00:10:19,910 --> 00:10:17,279 now call galaxies because we know that 294 00:10:23,190 --> 00:10:19,920 they're outside of our own milky way so 295 00:10:25,829 --> 00:10:23,200 he measured a bunch of redshifts and uh 296 00:10:27,350 --> 00:10:25,839 and he noticed that in fact there were 297 00:10:29,190 --> 00:10:27,360 mostly redshifts and there was only a 298 00:10:31,030 --> 00:10:29,200 handful of galaxies that where he 299 00:10:33,269 --> 00:10:31,040 actually found blue shifts and then 300 00:10:35,350 --> 00:10:33,279 sometime later somebody called hubble 301 00:10:37,590 --> 00:10:35,360 came along and he looked at this data 302 00:10:39,750 --> 00:10:37,600 and he supplemented it with other data 303 00:10:41,590 --> 00:10:39,760 and he looked at it and he said okay 304 00:10:42,949 --> 00:10:41,600 let's measure the distances to these 305 00:10:44,790 --> 00:10:42,959 galaxies and see if there's a 306 00:10:47,750 --> 00:10:44,800 relationship between redshift and 307 00:10:49,430 --> 00:10:47,760 distance and so if we if we look at the 308 00:10:51,030 --> 00:10:49,440 sky and we look at all of these galaxies 309 00:10:53,269 --> 00:10:51,040 and we measure redshift so we might get 310 00:10:54,790 --> 00:10:53,279 a picture uh like like the next picture 311 00:10:57,030 --> 00:10:54,800 that i have here for you this was this 312 00:10:59,750 --> 00:10:57,040 picture was actually made a lot after 313 00:11:03,190 --> 00:10:59,760 after um slifer and hubble this was from 314 00:11:04,790 --> 00:11:03,200 a an experiment called two mass um so 315 00:11:05,829 --> 00:11:04,800 here you have lots of little dots and 316 00:11:07,350 --> 00:11:05,839 they have different colors and the 317 00:11:08,790 --> 00:11:07,360 different colors correspond to different 318 00:11:10,710 --> 00:11:08,800 measurements a red shift so this is what 319 00:11:11,829 --> 00:11:10,720 this would look like on the sky 320 00:11:13,750 --> 00:11:11,839 and but 321 00:11:15,030 --> 00:11:13,760 what if so so as i said before what if 322 00:11:16,710 --> 00:11:15,040 hubble said what if we can measure 323 00:11:18,550 --> 00:11:16,720 distances to all of these galaxies and 324 00:11:21,190 --> 00:11:18,560 see if there's a relationship in fact 325 00:11:23,269 --> 00:11:21,200 there is a relationship and i have an 326 00:11:24,949 --> 00:11:23,279 equation for you now so brace yourselves 327 00:11:26,790 --> 00:11:24,959 so if you show the next picture it's the 328 00:11:28,470 --> 00:11:26,800 only equation i promise and it's just to 329 00:11:29,829 --> 00:11:28,480 illustrate the importance of the 330 00:11:31,670 --> 00:11:29,839 redshift distance relation so what 331 00:11:33,670 --> 00:11:31,680 you're seeing here on the left hand side 332 00:11:35,350 --> 00:11:33,680 there's a d with a subscript a and 333 00:11:37,509 --> 00:11:35,360 that's the angular diameter distance as 334 00:11:39,430 --> 00:11:37,519 we call it and on the right hand side 335 00:11:41,350 --> 00:11:39,440 there's the letter c which is the speed 336 00:11:43,030 --> 00:11:41,360 of light as the speed of light we have 337 00:11:44,470 --> 00:11:43,040 the letter z which is the red shift and 338 00:11:46,710 --> 00:11:44,480 then an integral 339 00:11:49,190 --> 00:11:46,720 of one over a function called h that's 340 00:11:51,670 --> 00:11:49,200 called the hubble function and that 341 00:11:53,350 --> 00:11:51,680 function contains all the information 342 00:11:55,190 --> 00:11:53,360 well a lot of the information about what 343 00:11:57,910 --> 00:11:55,200 the universe is made of 344 00:11:59,829 --> 00:11:57,920 and it tells you a lot about the history 345 00:12:01,430 --> 00:11:59,839 of our cosmos so if you can measure the 346 00:12:03,509 --> 00:12:01,440 d the distance and if you if you can 347 00:12:05,750 --> 00:12:03,519 measure the z the red shift so this is 348 00:12:07,190 --> 00:12:05,760 the distance redshift relation then you 349 00:12:09,750 --> 00:12:07,200 can infer 350 00:12:11,509 --> 00:12:09,760 so much about our cosmology about this h 351 00:12:14,310 --> 00:12:11,519 function about what the universe is made 352 00:12:16,310 --> 00:12:14,320 of and it's causing history and so now 353 00:12:18,310 --> 00:12:16,320 if i can show you a picture of what 354 00:12:20,870 --> 00:12:18,320 happens if you plo if you 355 00:12:22,710 --> 00:12:20,880 connect distances and redships together 356 00:12:23,910 --> 00:12:22,720 so these dots on this picture this is 357 00:12:26,389 --> 00:12:23,920 again from two masks they're all 358 00:12:29,829 --> 00:12:26,399 different galaxies and the colors denote 359 00:12:31,350 --> 00:12:29,839 uh the red shifts and of course distance 360 00:12:33,509 --> 00:12:31,360 is distance and we sit in the center 361 00:12:36,870 --> 00:12:33,519 we're the observer and you can see that 362 00:12:38,389 --> 00:12:36,880 redshift increases with distance and so 363 00:12:39,590 --> 00:12:38,399 when hubble realized this of course he 364 00:12:41,509 --> 00:12:39,600 didn't have a picture as nice as this 365 00:12:42,870 --> 00:12:41,519 but he had something like that when he 366 00:12:45,030 --> 00:12:42,880 realized he when he saw this 367 00:12:47,030 --> 00:12:45,040 relationship he said oh wait a minute 368 00:12:49,269 --> 00:12:47,040 that must mean that the universe itself 369 00:12:51,269 --> 00:12:49,279 is expanding space itself is pulling 370 00:12:53,829 --> 00:12:51,279 these galaxies apart so that those that 371 00:12:56,550 --> 00:12:53,839 are the furthest away from us are seem 372 00:12:58,870 --> 00:12:56,560 to be moving away from us at the highest 373 00:13:01,829 --> 00:12:58,880 speed and so this way if we can make 374 00:13:04,389 --> 00:13:01,839 these kinds of three-dimensional 375 00:13:06,069 --> 00:13:04,399 maps of the universe or the of the expan 376 00:13:07,430 --> 00:13:06,079 of the distribution of galaxies in the 377 00:13:10,790 --> 00:13:07,440 universe 378 00:13:13,829 --> 00:13:10,800 we can look both far away into space but 379 00:13:16,230 --> 00:13:13,839 we can also look far away into the past 380 00:13:17,269 --> 00:13:16,240 and that's because light has a finite 381 00:13:19,509 --> 00:13:17,279 speed 382 00:13:21,350 --> 00:13:19,519 so that if i'm receiving if i'm looking 383 00:13:23,750 --> 00:13:21,360 at a galaxy with of course a big 384 00:13:25,670 --> 00:13:23,760 telescope it's very very far away what 385 00:13:28,310 --> 00:13:25,680 i'm seeing is not the galaxy as it is 386 00:13:30,870 --> 00:13:28,320 today but a galaxy the galaxy as it was 387 00:13:32,550 --> 00:13:30,880 when light left this galaxy which may 388 00:13:34,310 --> 00:13:32,560 well have been billions and billions of 389 00:13:36,069 --> 00:13:34,320 years ago and so this way as we look 390 00:13:38,629 --> 00:13:36,079 into the distance we looked into the 391 00:13:40,389 --> 00:13:38,639 cosmic past and phil i think has a nice 392 00:13:42,710 --> 00:13:40,399 picture to show you what happens if you 393 00:13:44,230 --> 00:13:42,720 look through you well you might what you 394 00:13:46,310 --> 00:13:44,240 might see if you look through the cosmic 395 00:13:48,710 --> 00:13:46,320 past 396 00:13:51,590 --> 00:13:48,720 right yeah so uh if we bring up the next 397 00:13:53,110 --> 00:13:51,600 slide uh let's uh you know look at some 398 00:13:55,750 --> 00:13:53,120 of the implications of those concepts 399 00:13:58,710 --> 00:13:55,760 that did just introduced right so this 400 00:14:00,550 --> 00:13:58,720 figure is is a cartoon of 401 00:14:02,790 --> 00:14:00,560 the history and the evolution of the 402 00:14:05,829 --> 00:14:02,800 universe that arrow that goes from left 403 00:14:07,509 --> 00:14:05,839 to right represents uh time from the 404 00:14:09,829 --> 00:14:07,519 very beginning until today which is all 405 00:14:12,470 --> 00:14:09,839 the way on the right side where you see 406 00:14:14,550 --> 00:14:12,480 today the structure of the universe as 407 00:14:17,910 --> 00:14:14,560 as we know it that has all sorts of 408 00:14:19,110 --> 00:14:17,920 galaxies populating this cosmic web of 409 00:14:21,670 --> 00:14:19,120 structure 410 00:14:23,509 --> 00:14:21,680 and you know this diffuse light that's 411 00:14:25,269 --> 00:14:23,519 that's uh that's out there today that 412 00:14:27,189 --> 00:14:25,279 came from all sorts of tidal 413 00:14:30,710 --> 00:14:27,199 interactions in the history of uh the 414 00:14:33,509 --> 00:14:30,720 evolution of galaxies where you know fly 415 00:14:34,949 --> 00:14:33,519 stars get flung out way into their um 416 00:14:36,310 --> 00:14:34,959 excerpts 417 00:14:39,509 --> 00:14:36,320 so if we think about 418 00:14:41,430 --> 00:14:39,519 observing today in the near infrared all 419 00:14:42,949 --> 00:14:41,440 of those galaxies in their what's called 420 00:14:45,990 --> 00:14:42,959 a rest frame so 421 00:14:48,949 --> 00:14:46,000 in in today's uh unread shifted 422 00:14:50,550 --> 00:14:48,959 wavelengths they're emitting in the in 423 00:14:52,310 --> 00:14:50,560 the near infrared and they they peak 424 00:14:54,629 --> 00:14:52,320 there because they have a bunch of stars 425 00:14:56,949 --> 00:14:54,639 which are you know cooler than than than 426 00:14:59,829 --> 00:14:56,959 our sun but if we think about now 427 00:15:02,310 --> 00:14:59,839 looking further away hence further back 428 00:15:06,069 --> 00:15:02,320 in time also since the universe is 429 00:15:09,430 --> 00:15:06,079 expanding we're looking at sources that 430 00:15:12,550 --> 00:15:09,440 are redshifted far away so if you go all 431 00:15:15,110 --> 00:15:12,560 the way back to about you know only 432 00:15:16,470 --> 00:15:15,120 um you know ten to tens of billions of 433 00:15:18,710 --> 00:15:16,480 years ago 434 00:15:22,069 --> 00:15:18,720 uh the first stars in galaxies which 435 00:15:24,389 --> 00:15:22,079 were forming out of the the the neutral 436 00:15:27,350 --> 00:15:24,399 hydrogen which cooled and and condensed 437 00:15:29,670 --> 00:15:27,360 and those first stars turned on emitting 438 00:15:31,829 --> 00:15:29,680 in their rest frame ultraviolet so 439 00:15:36,150 --> 00:15:31,839 really blue and really hot that's now 440 00:15:38,230 --> 00:15:36,160 red shifted into into our uh observation 441 00:15:39,509 --> 00:15:38,240 so um when we talk about the infrared 442 00:15:41,509 --> 00:15:39,519 background another term that we use is 443 00:15:43,350 --> 00:15:41,519 the extra galactic background light 444 00:15:45,670 --> 00:15:43,360 we're thinking about the integral we're 445 00:15:48,710 --> 00:15:45,680 measuring the integrated light 446 00:15:51,430 --> 00:15:48,720 production in all of cosmic history 447 00:15:52,150 --> 00:15:51,440 and it turns out that the 448 00:15:54,150 --> 00:15:52,160 uh 449 00:15:55,990 --> 00:15:54,160 when we look at the structure today in 450 00:15:57,990 --> 00:15:56,000 galaxies the way they're populating in 451 00:16:00,949 --> 00:15:58,000 this web 452 00:16:03,829 --> 00:16:00,959 all of that structure was seeded at the 453 00:16:05,910 --> 00:16:03,839 very earliest epochs 454 00:16:07,670 --> 00:16:05,920 right after the big bang in an epic 455 00:16:08,790 --> 00:16:07,680 called inflation so there are these two 456 00:16:10,629 --> 00:16:08,800 epics 457 00:16:13,269 --> 00:16:10,639 in in in 458 00:16:15,430 --> 00:16:13,279 of of rapid expansion in cosmic history 459 00:16:18,470 --> 00:16:15,440 that early epic of inflation and then 460 00:16:21,990 --> 00:16:18,480 today where dark energy uh is taking 461 00:16:24,150 --> 00:16:22,000 over and is expanding our universe uh 462 00:16:26,150 --> 00:16:24,160 rapidly so the large-scale structure 463 00:16:28,629 --> 00:16:26,160 today is tied to those 464 00:16:30,710 --> 00:16:28,639 earliest epics through what was seated 465 00:16:32,629 --> 00:16:30,720 as quantum fluctuations which i'm going 466 00:16:33,910 --> 00:16:32,639 to pass it back to uh deeda to tell you 467 00:16:35,670 --> 00:16:33,920 a bit about 468 00:16:37,829 --> 00:16:35,680 yeah if you would be so kind can you 469 00:16:40,230 --> 00:16:37,839 elaborate on those a bit 470 00:16:42,310 --> 00:16:40,240 yes i'm happy to in fact i can even show 471 00:16:43,749 --> 00:16:42,320 an animation so if you show the next 472 00:16:45,430 --> 00:16:43,759 thing that we have to show 473 00:16:47,670 --> 00:16:45,440 thank you so 474 00:16:49,749 --> 00:16:47,680 there's something really strange 475 00:16:52,069 --> 00:16:49,759 happening if you look at empty vacuum of 476 00:16:53,350 --> 00:16:52,079 space so if you were able to go into the 477 00:16:55,430 --> 00:16:53,360 vacuum and see what it looks like it 478 00:16:57,030 --> 00:16:55,440 might look pretty boring to you but if 479 00:17:00,069 --> 00:16:57,040 you could zoom in and look on the 480 00:17:02,069 --> 00:17:00,079 tiniest microscopic quantum scales you 481 00:17:03,910 --> 00:17:02,079 would see that it's anything but boring 482 00:17:05,590 --> 00:17:03,920 now of course we can't do that we can't 483 00:17:07,750 --> 00:17:05,600 see these scales even with the best 484 00:17:10,150 --> 00:17:07,760 microscopes we can only see hints of it 485 00:17:12,150 --> 00:17:10,160 and we certainly can't observe what we 486 00:17:13,590 --> 00:17:12,160 um you know this this kind of thing that 487 00:17:14,949 --> 00:17:13,600 i'm showing you here and what i'm 488 00:17:16,630 --> 00:17:14,959 showing you here is called quantum 489 00:17:19,110 --> 00:17:16,640 fluctuation it's kind of like this 490 00:17:21,350 --> 00:17:19,120 bubbling on quantum scales and what's 491 00:17:24,069 --> 00:17:21,360 happening is that basically out of 492 00:17:25,990 --> 00:17:24,079 nowhere uh pairs of particles and 493 00:17:28,069 --> 00:17:26,000 anti-particles are as if they're 494 00:17:30,070 --> 00:17:28,079 borrowing energy from empty space and 495 00:17:31,270 --> 00:17:30,080 coming into existence and then a small 496 00:17:33,110 --> 00:17:31,280 fraction of a second later they're 497 00:17:35,270 --> 00:17:33,120 annihilating each other and returning 498 00:17:37,270 --> 00:17:35,280 this energy back into space 499 00:17:39,750 --> 00:17:37,280 and this was actually also happening at 500 00:17:41,750 --> 00:17:39,760 the very very beginning of the universe 501 00:17:44,310 --> 00:17:41,760 except that back then things were even 502 00:17:46,070 --> 00:17:44,320 stranger at the very very first moments 503 00:17:48,390 --> 00:17:46,080 of our universe the universe was really 504 00:17:49,590 --> 00:17:48,400 dense and really hot and then these 505 00:17:51,350 --> 00:17:49,600 things were bubbling the quantum 506 00:17:52,789 --> 00:17:51,360 fluctuations were happening 507 00:17:55,990 --> 00:17:52,799 and suddenly 508 00:17:58,390 --> 00:17:56,000 space itself started to expand 509 00:17:59,750 --> 00:17:58,400 in a really really dramatic way not just 510 00:18:01,990 --> 00:17:59,760 expand but 511 00:18:03,590 --> 00:18:02,000 accelerate so it was speeding up the 512 00:18:05,669 --> 00:18:03,600 expansion was speeding up as as phil 513 00:18:07,909 --> 00:18:05,679 mentioned and we called this process in 514 00:18:10,549 --> 00:18:07,919 the early universe we call it inflation 515 00:18:12,150 --> 00:18:10,559 and we don't really understand what 516 00:18:13,190 --> 00:18:12,160 drove it and why it happened and we 517 00:18:14,390 --> 00:18:13,200 don't understand the thing that's 518 00:18:17,510 --> 00:18:14,400 powering it 519 00:18:19,669 --> 00:18:17,520 but as the universe expanded it also the 520 00:18:20,549 --> 00:18:19,679 density dropped and it cooled 521 00:18:22,630 --> 00:18:20,559 and 522 00:18:24,950 --> 00:18:22,640 this thing that was powering this 523 00:18:26,710 --> 00:18:24,960 inflation it underwent something that we 524 00:18:29,029 --> 00:18:26,720 call you could call a phase transition 525 00:18:31,909 --> 00:18:29,039 so what happened was that the cooling 526 00:18:34,310 --> 00:18:31,919 pushed this strange stuff to decay into 527 00:18:36,310 --> 00:18:34,320 more familiar particles of you know that 528 00:18:38,710 --> 00:18:36,320 make us up and you know that we can 529 00:18:40,870 --> 00:18:38,720 interact with also a bunch of other 530 00:18:43,270 --> 00:18:40,880 weird stuff on the side but that's too 531 00:18:45,990 --> 00:18:43,280 and so the universe was expanding and 532 00:18:47,990 --> 00:18:46,000 and as inflation was over very quickly a 533 00:18:50,789 --> 00:18:48,000 very small fraction of a second 534 00:18:52,630 --> 00:18:50,799 um it it what it had done is it pulled 535 00:18:55,669 --> 00:18:52,640 these quantum fluctuations from these 536 00:18:58,310 --> 00:18:55,679 tiny microscopic scales to macroscopic 537 00:19:01,190 --> 00:18:58,320 observable scales and so these this 538 00:19:03,590 --> 00:19:01,200 these little these little uh bumps they 539 00:19:05,510 --> 00:19:03,600 were kind of small and big bumps on all 540 00:19:07,510 --> 00:19:05,520 scales were frozen in so they didn't 541 00:19:10,390 --> 00:19:07,520 bubble anymore but they were there also 542 00:19:12,789 --> 00:19:10,400 on observable microscopic scales and so 543 00:19:14,870 --> 00:19:12,799 in and so what we had now after a very 544 00:19:16,710 --> 00:19:14,880 maybe a very small amount of time at the 545 00:19:19,430 --> 00:19:16,720 beginning of the universe we had this 546 00:19:21,190 --> 00:19:19,440 this lumpy soup that was made up of you 547 00:19:23,750 --> 00:19:21,200 know particles of normal matter but also 548 00:19:25,190 --> 00:19:23,760 of dark matter and this lumpy soup of 549 00:19:28,070 --> 00:19:25,200 course was being governed by the laws of 550 00:19:29,909 --> 00:19:28,080 physics so it felt gravity and it felt 551 00:19:31,430 --> 00:19:29,919 pressure so these little lumps in the 552 00:19:33,750 --> 00:19:31,440 soup felt pressure and they certainly 553 00:19:35,430 --> 00:19:33,760 started inflating into these 554 00:19:36,710 --> 00:19:35,440 bubbles of sound so sound was 555 00:19:38,470 --> 00:19:36,720 propagating through 556 00:19:40,390 --> 00:19:38,480 this early universe 557 00:19:42,470 --> 00:19:40,400 and so and now 558 00:19:44,390 --> 00:19:42,480 you know this situation kind of lasted 559 00:19:45,510 --> 00:19:44,400 for hundreds of thousands of years so 560 00:19:46,870 --> 00:19:45,520 we're going we've gone from a fraction 561 00:19:48,549 --> 00:19:46,880 of a second to hundreds of thousands of 562 00:19:50,789 --> 00:19:48,559 years and after some hundreds of 563 00:19:52,390 --> 00:19:50,799 thousands of years the this sounds 564 00:19:55,669 --> 00:19:52,400 stopped propagating because the density 565 00:19:57,590 --> 00:19:55,679 dropped so much and these these bubbles 566 00:19:59,669 --> 00:19:57,600 of sound that were propagating through 567 00:20:01,430 --> 00:19:59,679 they got frozen in so i'm gonna have an 568 00:20:04,070 --> 00:20:01,440 animation for you to show these bubbles 569 00:20:05,990 --> 00:20:04,080 of sound and what happened afterwards so 570 00:20:08,230 --> 00:20:06,000 the bubbles of sound uh so if you go to 571 00:20:10,789 --> 00:20:08,240 the next animation please um the bubbles 572 00:20:13,110 --> 00:20:10,799 of sound were also um you know uh 573 00:20:15,110 --> 00:20:13,120 influenced by gravity so the the shells 574 00:20:17,750 --> 00:20:15,120 of these bubbles fragmented under 575 00:20:19,830 --> 00:20:17,760 gravity and collapsed into galaxies 576 00:20:22,070 --> 00:20:19,840 but galaxies also formed at the centers 577 00:20:23,430 --> 00:20:22,080 of the bubbles and that was because of 578 00:20:26,630 --> 00:20:23,440 dark matter 579 00:20:28,149 --> 00:20:26,640 didn't feel this pressure at the 580 00:20:29,590 --> 00:20:28,159 beginning of the universe it didn't you 581 00:20:31,750 --> 00:20:29,600 know sound wasn't propagating through it 582 00:20:34,230 --> 00:20:31,760 so it kind of remained in the locations 583 00:20:36,070 --> 00:20:34,240 of those original lumps and then it also 584 00:20:38,549 --> 00:20:36,080 attracted lots of normal matter towards 585 00:20:40,390 --> 00:20:38,559 them and that's what that normal matter 586 00:20:42,149 --> 00:20:40,400 then fragmented under gravity into 587 00:20:43,669 --> 00:20:42,159 galaxies and collapsed 588 00:20:46,070 --> 00:20:43,679 and the really cool thing about thing 589 00:20:47,590 --> 00:20:46,080 about these bubbles is that the physics 590 00:20:49,590 --> 00:20:47,600 to calculate their size is pretty 591 00:20:51,990 --> 00:20:49,600 straightforward so we can actually 592 00:20:55,669 --> 00:20:52,000 calculate how big we expect them to be 593 00:20:57,510 --> 00:20:55,679 today so this is 150 megaparsecs and 594 00:20:59,350 --> 00:20:57,520 and so if we look at the sky and we know 595 00:21:01,430 --> 00:20:59,360 how big these bubbles are supposed to be 596 00:21:03,029 --> 00:21:01,440 if we can see them and measure how big 597 00:21:05,029 --> 00:21:03,039 they appear then we could measure 598 00:21:07,270 --> 00:21:05,039 distances so it turns out that these 599 00:21:09,909 --> 00:21:07,280 bubbles were discovered 600 00:21:12,149 --> 00:21:09,919 in astronomy about 15 years ago they're 601 00:21:14,470 --> 00:21:12,159 called baryonic acoustic oscillations 602 00:21:16,710 --> 00:21:14,480 formally and they are an amazing measure 603 00:21:18,149 --> 00:21:16,720 of distance throughout a huge amount of 604 00:21:19,990 --> 00:21:18,159 the universe so looking back into the 605 00:21:22,390 --> 00:21:20,000 past you can measure distances to really 606 00:21:24,630 --> 00:21:22,400 distant galaxies but you can only do it 607 00:21:27,669 --> 00:21:24,640 statistically so 608 00:21:30,310 --> 00:21:27,679 using this this measurement of of this 609 00:21:31,990 --> 00:21:30,320 of distance that is that works so well 610 00:21:34,870 --> 00:21:32,000 and then measuring the redshifts of the 611 00:21:36,789 --> 00:21:34,880 galaxies that make up these bubbles um 612 00:21:38,710 --> 00:21:36,799 then you can calculate this distance 613 00:21:41,110 --> 00:21:38,720 redshift relation and you can see this 614 00:21:43,190 --> 00:21:41,120 effect you can see the effect that the 615 00:21:45,750 --> 00:21:43,200 unit as phil mentioned that the universe 616 00:21:47,029 --> 00:21:45,760 started accelerating uh 617 00:21:49,270 --> 00:21:47,039 as to the expansion of the universe 618 00:21:51,029 --> 00:21:49,280 started accelerating again billions of 619 00:21:53,430 --> 00:21:51,039 years after inflation and this 620 00:21:54,950 --> 00:21:53,440 accelerated expansion uh is we say that 621 00:21:56,549 --> 00:21:54,960 it's fueled by dark energy as phil 622 00:21:59,830 --> 00:21:56,559 mentioned and we don't really know what 623 00:22:02,390 --> 00:21:59,840 dark energy is and so in fact dark 624 00:22:05,190 --> 00:22:02,400 energy and inflation are two of the 625 00:22:08,149 --> 00:22:05,200 biggest mysteries of modern physics and 626 00:22:10,149 --> 00:22:08,159 that's really exciting too to work on 627 00:22:11,990 --> 00:22:10,159 that's really really cool 628 00:22:13,430 --> 00:22:12,000 um so let me call for the next slide and 629 00:22:14,950 --> 00:22:13,440 kind of summarize what you two have 630 00:22:16,630 --> 00:22:14,960 talked about so far so there have been 631 00:22:18,470 --> 00:22:16,640 two epochs where the expansion of the 632 00:22:21,190 --> 00:22:18,480 universe was speeding up 633 00:22:22,870 --> 00:22:21,200 uh the first epic was called inflation 634 00:22:24,870 --> 00:22:22,880 and then the current expansion which is 635 00:22:26,470 --> 00:22:24,880 due to dark energy 636 00:22:28,230 --> 00:22:26,480 there's a wealth of information related 637 00:22:29,750 --> 00:22:28,240 to both of these phenomena buried in the 638 00:22:30,870 --> 00:22:29,760 large scale structure of the universe 639 00:22:32,390 --> 00:22:30,880 and these two missions are going to help 640 00:22:33,669 --> 00:22:32,400 us you know pull some of that out so the 641 00:22:35,270 --> 00:22:33,679 euclid mission 642 00:22:36,710 --> 00:22:35,280 will probe the structure at about half 643 00:22:38,470 --> 00:22:36,720 the age of the universe if i got that 644 00:22:40,549 --> 00:22:38,480 right and from that we'll infer what 645 00:22:42,870 --> 00:22:40,559 dark energy is doing 646 00:22:44,789 --> 00:22:42,880 to the universe's expansion today 647 00:22:47,270 --> 00:22:44,799 and then the spherex mission 648 00:22:49,590 --> 00:22:47,280 will survey a huge volume of large scale 649 00:22:51,190 --> 00:22:49,600 structure in the nearby universe and 650 00:22:53,750 --> 00:22:51,200 from that will teach us about the energy 651 00:22:56,870 --> 00:22:53,760 field or fields that drove inflation in 652 00:22:59,270 --> 00:22:56,880 the first instance of cosmic history 653 00:23:01,270 --> 00:22:59,280 so phil let's bring you back um if you 654 00:23:03,590 --> 00:23:01,280 please tell us about the spherics 655 00:23:05,669 --> 00:23:03,600 mission that you're working on 656 00:23:07,029 --> 00:23:05,679 all right yeah well i've got an overview 657 00:23:10,549 --> 00:23:07,039 on the next slide 658 00:23:12,950 --> 00:23:10,559 and so spherex is uh is indeed another 659 00:23:14,789 --> 00:23:12,960 it's a tortured acronym it stands for 660 00:23:17,590 --> 00:23:14,799 the spectrophotometer for the history of 661 00:23:19,110 --> 00:23:17,600 the universe epic of reionization 662 00:23:22,950 --> 00:23:19,120 explorer 663 00:23:25,590 --> 00:23:22,960 and um it's designed really as as one of 664 00:23:27,909 --> 00:23:25,600 the first uh missions where not only are 665 00:23:30,390 --> 00:23:27,919 we gonna make a map of the whole sky in 666 00:23:32,630 --> 00:23:30,400 imaging but we're gonna take a spectrum 667 00:23:35,029 --> 00:23:32,640 towards every single pointing at a 668 00:23:36,630 --> 00:23:35,039 resolution of six arc seconds in the 669 00:23:38,789 --> 00:23:36,640 entire universe 670 00:23:41,510 --> 00:23:38,799 and from that huge data set we've 671 00:23:44,230 --> 00:23:41,520 optimized further to really get at these 672 00:23:46,149 --> 00:23:44,240 three main science themes the first is 673 00:23:48,470 --> 00:23:46,159 as we've been discussing to measure the 674 00:23:51,350 --> 00:23:48,480 large scale structure in today's 675 00:23:53,990 --> 00:23:51,360 universe so tracing all the galaxies as 676 00:23:56,710 --> 00:23:54,000 they populate this cosmic web and by 677 00:23:58,870 --> 00:23:56,720 doing statistics on the relations and 678 00:24:00,390 --> 00:23:58,880 how clumpy and clustered they are to tie 679 00:24:03,029 --> 00:24:00,400 that back to those 680 00:24:04,549 --> 00:24:03,039 quantum fluctuations at the at the real 681 00:24:06,470 --> 00:24:04,559 dawn 682 00:24:08,630 --> 00:24:06,480 during inflation 683 00:24:10,630 --> 00:24:08,640 but also we're going to measure that 684 00:24:12,470 --> 00:24:10,640 integrated light field in the extra 685 00:24:15,029 --> 00:24:12,480 galactic background light 686 00:24:16,710 --> 00:24:15,039 and from that to disentangle the various 687 00:24:19,190 --> 00:24:16,720 components which came from that epoch of 688 00:24:21,430 --> 00:24:19,200 realization the or the the time when the 689 00:24:24,230 --> 00:24:21,440 those first stars and galaxies were 690 00:24:26,549 --> 00:24:24,240 turning on and and evolving through 691 00:24:28,230 --> 00:24:26,559 cosmic time till today where there's all 692 00:24:30,630 --> 00:24:28,240 sorts of diffuse light that's gotten 693 00:24:32,789 --> 00:24:30,640 flung out to the far reaches of excerpts 694 00:24:34,310 --> 00:24:32,799 but also at our 695 00:24:37,350 --> 00:24:34,320 more close to home in our own 696 00:24:39,590 --> 00:24:37,360 neighborhood of the milky way so our 697 00:24:43,269 --> 00:24:39,600 parent galaxy that we live in 698 00:24:49,430 --> 00:24:46,789 this significant feature of absorption 699 00:24:51,350 --> 00:24:49,440 that comes from ice so just water ice 700 00:24:53,750 --> 00:24:51,360 and we're going to survey 701 00:24:56,870 --> 00:24:53,760 our galactic plane in our neighborhood 702 00:24:58,470 --> 00:24:56,880 for water ice absorption and as we know 703 00:25:01,190 --> 00:24:58,480 at least on earth 704 00:25:03,990 --> 00:25:01,200 where we're looking for life uh we're 705 00:25:05,669 --> 00:25:04,000 looking for water and so most of the ice 706 00:25:07,669 --> 00:25:05,679 most of the water in the universe is 707 00:25:09,750 --> 00:25:07,679 actually not liquid it's in ice form so 708 00:25:10,789 --> 00:25:09,760 spherics is going to survey the galactic 709 00:25:13,190 --> 00:25:10,799 plane 710 00:25:14,789 --> 00:25:13,200 for water ice absorption 711 00:25:17,350 --> 00:25:14,799 uh on the next slide i'll show you a 712 00:25:20,630 --> 00:25:17,360 movie of how we implement this so 713 00:25:22,630 --> 00:25:20,640 spherex it it lives in what we call a 714 00:25:25,269 --> 00:25:22,640 sun synchronous low earth 715 00:25:27,269 --> 00:25:25,279 polar orbit so at about 700 kilometers 716 00:25:28,870 --> 00:25:27,279 over the earth we're going around on 717 00:25:31,350 --> 00:25:28,880 this terminator line so it's always 718 00:25:33,750 --> 00:25:31,360 sunrise or sunset for spherex and we 719 00:25:35,750 --> 00:25:33,760 keep our solar panels there to the our 720 00:25:37,430 --> 00:25:35,760 back to the sun to keep us nice and 721 00:25:40,390 --> 00:25:37,440 charged up and powered 722 00:25:43,029 --> 00:25:40,400 now you can see as we pan up spherex has 723 00:25:45,190 --> 00:25:43,039 the set of three nestled shields we call 724 00:25:47,430 --> 00:25:45,200 them photon shields 725 00:25:49,269 --> 00:25:47,440 their job is to block the radiation 726 00:25:51,510 --> 00:25:49,279 which is coming up off the earth the 727 00:25:53,430 --> 00:25:51,520 thermal radiation from the earth as well 728 00:25:55,190 --> 00:25:53,440 as the sunlight from getting to the core 729 00:25:56,549 --> 00:25:55,200 of spherex which is that telescope you 730 00:25:58,230 --> 00:25:56,559 can see there 731 00:26:00,149 --> 00:25:58,240 this telescope because we're working in 732 00:26:02,710 --> 00:26:00,159 the near infrared has to be cooled to 733 00:26:05,510 --> 00:26:02,720 really low temperatures and we do so 734 00:26:06,789 --> 00:26:05,520 passively using the actual cold of deep 735 00:26:08,870 --> 00:26:06,799 space 736 00:26:13,110 --> 00:26:08,880 doing that we can cool this telescope 737 00:26:14,870 --> 00:26:13,120 down to 40 kelvin uh you know most of us 738 00:26:16,710 --> 00:26:14,880 at least in america think in terms of 739 00:26:20,149 --> 00:26:16,720 fahrenheit that's the equivalent of 740 00:26:22,830 --> 00:26:20,159 minus 387 fahrenheit and we need to get 741 00:26:25,430 --> 00:26:22,840 down that that low to control the 742 00:26:27,110 --> 00:26:25,440 emission actually the light emitted from 743 00:26:29,029 --> 00:26:27,120 our telescope 744 00:26:30,470 --> 00:26:29,039 at the core of sphere x 745 00:26:32,390 --> 00:26:30,480 is uh 746 00:26:34,070 --> 00:26:32,400 what we call a linear variable filter an 747 00:26:35,510 --> 00:26:34,080 lvf and i've got a picture of one on the 748 00:26:37,110 --> 00:26:35,520 next slide 749 00:26:39,269 --> 00:26:37,120 and this is where we get all of our 750 00:26:41,430 --> 00:26:39,279 spectroscopic power it's a really 751 00:26:43,190 --> 00:26:41,440 efficient way of doing this in space 752 00:26:45,430 --> 00:26:43,200 it's a little piece of actually of 753 00:26:47,990 --> 00:26:45,440 sapphire which has a very special 754 00:26:51,029 --> 00:26:48,000 optical coating on it which only 755 00:26:53,669 --> 00:26:51,039 transmits selected wavelengths depending 756 00:26:55,350 --> 00:26:53,679 on where you land on the filter so in 757 00:26:57,029 --> 00:26:55,360 that picture you're looking at you could 758 00:26:58,149 --> 00:26:57,039 think of on the left 759 00:27:00,390 --> 00:26:58,159 um 760 00:27:02,230 --> 00:27:00,400 it would only let through blue or light 761 00:27:03,750 --> 00:27:02,240 and then towards the the right it would 762 00:27:06,390 --> 00:27:03,760 let through the redder light so 763 00:27:09,110 --> 00:27:06,400 depending on where a source or galaxy 764 00:27:11,190 --> 00:27:09,120 lands on our filter we're measuring it 765 00:27:13,510 --> 00:27:11,200 at a different wavelength now we use 766 00:27:15,510 --> 00:27:13,520 these linear variable filters in concert 767 00:27:17,350 --> 00:27:15,520 with a wide field telescope and if you 768 00:27:20,789 --> 00:27:17,360 go to the next slide 769 00:27:22,549 --> 00:27:20,799 i'll show you how how that looks so the 770 00:27:24,549 --> 00:27:22,559 telescope is made entirely out of 771 00:27:26,950 --> 00:27:24,559 aluminum and it's actually a pretty 772 00:27:29,029 --> 00:27:26,960 modest size the aperture or the primary 773 00:27:31,669 --> 00:27:29,039 mirror is only about 20 centimeters so 774 00:27:32,870 --> 00:27:31,679 kind of kind of basketball sized and if 775 00:27:34,950 --> 00:27:32,880 we cut it in half there you can see 776 00:27:37,110 --> 00:27:34,960 we've got three mirrors now a 777 00:27:38,950 --> 00:27:37,120 telescope's job is to is to take light 778 00:27:41,750 --> 00:27:38,960 from the other side of the universe so 779 00:27:44,310 --> 00:27:41,760 collimated light that has parallel rays 780 00:27:45,830 --> 00:27:44,320 and it brings it to a focus at what we 781 00:27:48,389 --> 00:27:45,840 call the focal plane that's highlighted 782 00:27:51,029 --> 00:27:48,399 and that's in that square there at that 783 00:27:54,389 --> 00:27:51,039 focal plane we place an assembly of 784 00:27:56,470 --> 00:27:54,399 three detectors each of which has their 785 00:27:58,470 --> 00:27:56,480 own linear variable filters so depending 786 00:27:59,830 --> 00:27:58,480 on where the light hits we're measuring 787 00:28:01,029 --> 00:27:59,840 it at a certain wavelength so you can 788 00:28:03,269 --> 00:28:01,039 see that light 789 00:28:04,950 --> 00:28:03,279 going through at a certain position 790 00:28:06,310 --> 00:28:04,960 we'll make an image and it might look 791 00:28:07,269 --> 00:28:06,320 something like what you see on the left 792 00:28:09,269 --> 00:28:07,279 there 793 00:28:11,430 --> 00:28:09,279 we tally up all the light that got 794 00:28:14,230 --> 00:28:11,440 detected there and from that we've now 795 00:28:17,029 --> 00:28:14,240 made a single point on the spectrum 796 00:28:18,870 --> 00:28:17,039 if we move our telescope so that that 797 00:28:21,190 --> 00:28:18,880 same source lands at a different 798 00:28:22,789 --> 00:28:21,200 position so we dithered it now we're 799 00:28:24,870 --> 00:28:22,799 measuring it at a different wavelength 800 00:28:26,789 --> 00:28:24,880 we make another image we add up all the 801 00:28:28,870 --> 00:28:26,799 photons that we detected and then we've 802 00:28:30,950 --> 00:28:28,880 got another point on our spectrum 803 00:28:33,110 --> 00:28:30,960 if you go ahead and repeat that about 50 804 00:28:36,470 --> 00:28:33,120 times we'll build up an entire 805 00:28:38,789 --> 00:28:36,480 near-infrared spectrum for that source 806 00:28:40,789 --> 00:28:38,799 um if you go to the next slide so so if 807 00:28:43,029 --> 00:28:40,799 we were if we were 808 00:28:44,950 --> 00:28:43,039 to do this only for an individual source 809 00:28:47,190 --> 00:28:44,960 that'd be really inefficient but the 810 00:28:49,190 --> 00:28:47,200 beauty of spherex is that we we're 811 00:28:51,669 --> 00:28:49,200 multiplexing heavily so in this 812 00:28:52,710 --> 00:28:51,679 animation i've hid that center lvf and 813 00:28:55,590 --> 00:28:52,720 instead 814 00:28:59,029 --> 00:28:55,600 we're placing a simulated image of what 815 00:29:01,029 --> 00:28:59,039 spherex's sky looks like put it to scale 816 00:29:01,750 --> 00:29:01,039 on that detector so now that we've flown 817 00:29:05,669 --> 00:29:01,760 in 818 00:29:08,389 --> 00:29:05,679 simultaneously 819 00:29:11,510 --> 00:29:08,399 a spectroscopic sample for hundreds of 820 00:29:13,669 --> 00:29:11,520 thousands of sources at every moment so 821 00:29:17,110 --> 00:29:13,679 we measure hundreds of thousands of 822 00:29:19,430 --> 00:29:17,120 sources at each time we take about 600 823 00:29:22,310 --> 00:29:19,440 exposures per day and then we do that 824 00:29:24,830 --> 00:29:22,320 relentlessly for two years building up 825 00:29:27,669 --> 00:29:24,840 spectroscopic data set for billions of 826 00:29:29,750 --> 00:29:27,679 objects on the next slide 827 00:29:32,310 --> 00:29:29,760 we show you how we do that 828 00:29:34,870 --> 00:29:32,320 so again we're going around the earth 829 00:29:36,950 --> 00:29:34,880 around that day night boundary 830 00:29:39,830 --> 00:29:36,960 and we dither our linear variable 831 00:29:43,029 --> 00:29:39,840 filters around as we as we fill in those 832 00:29:45,269 --> 00:29:43,039 gaps and so we put every single position 833 00:29:47,510 --> 00:29:45,279 on the celestial sphere to every 834 00:29:49,750 --> 00:29:47,520 position on our focal plane and then 835 00:29:52,070 --> 00:29:49,760 we're measuring it at all the wavelength 836 00:29:54,149 --> 00:29:52,080 so as the sphere x goes around the earth 837 00:29:56,470 --> 00:29:54,159 and the earth goes around the sun it 838 00:29:59,110 --> 00:29:56,480 gets modulated and moves around and in 839 00:30:02,389 --> 00:29:59,120 six months time we've built up a 840 00:30:05,029 --> 00:30:02,399 spectrum towards every point in the sky 841 00:30:07,590 --> 00:30:05,039 we do this four times and to build up a 842 00:30:08,549 --> 00:30:07,600 redundant spectroscopic sample 843 00:30:12,070 --> 00:30:08,559 to 844 00:30:16,389 --> 00:30:14,389 so on the next slide i'll show you a 845 00:30:18,710 --> 00:30:16,399 simulation of what we might expect from 846 00:30:21,510 --> 00:30:18,720 the sphere x data set and this is super 847 00:30:23,590 --> 00:30:21,520 exciting we're flying through now 848 00:30:26,070 --> 00:30:23,600 i think it's important to convey to you 849 00:30:28,310 --> 00:30:26,080 that this is actually it's it's not an 850 00:30:30,230 --> 00:30:28,320 artist representation this comes from an 851 00:30:33,190 --> 00:30:30,240 actual simulation that was done by our 852 00:30:35,110 --> 00:30:33,200 colleagues at argonne national labs 853 00:30:36,789 --> 00:30:35,120 who using what we know about the 854 00:30:38,789 --> 00:30:36,799 contents of the universe and the large 855 00:30:40,870 --> 00:30:38,799 scale structure 856 00:30:41,909 --> 00:30:40,880 simulate with a trillion particles in a 857 00:30:43,110 --> 00:30:41,919 computer 858 00:30:57,190 --> 00:30:43,120 that 859 00:30:59,909 --> 00:30:57,200 and so this kind of gives you a scale of 860 00:31:01,350 --> 00:30:59,919 just the the vastness of the data set i 861 00:31:03,669 --> 00:31:01,360 should also mention that what we're 862 00:31:06,230 --> 00:31:03,679 flying through right now is about 1 863 00:31:07,830 --> 00:31:06,240 200th of what the sphere x data set is 864 00:31:09,350 --> 00:31:07,840 going to look like 865 00:31:11,590 --> 00:31:09,360 and from 866 00:31:13,590 --> 00:31:11,600 once we have this three-dimensional map 867 00:31:16,149 --> 00:31:13,600 that has all of these galaxies spread 868 00:31:17,430 --> 00:31:16,159 out in space we'll do all our statistics 869 00:31:19,750 --> 00:31:17,440 on their clumpiness how they're 870 00:31:21,269 --> 00:31:19,760 associated with their neighbors on all 871 00:31:24,789 --> 00:31:21,279 sorts of scales including the large 872 00:31:26,789 --> 00:31:24,799 scales and from that to learn to tie 873 00:31:28,789 --> 00:31:26,799 that all the way back to the quantum 874 00:31:31,190 --> 00:31:28,799 fluctuations which seeded that large 875 00:31:32,950 --> 00:31:31,200 scale structure at the very earliest 876 00:31:34,950 --> 00:31:32,960 epics of the universe 877 00:31:36,549 --> 00:31:34,960 so as we're flying through we're flying 878 00:31:38,470 --> 00:31:36,559 away from the observer so we're looking 879 00:31:40,230 --> 00:31:38,480 back in time 880 00:31:42,470 --> 00:31:40,240 earlier and earlier in the universe's 881 00:31:44,389 --> 00:31:42,480 history and you can see as we as we 882 00:31:47,029 --> 00:31:44,399 start getting out here the number of 883 00:31:48,870 --> 00:31:47,039 galaxies is going down now that's not 884 00:31:50,870 --> 00:31:48,880 because the number of galaxies in the 885 00:31:53,669 --> 00:31:50,880 universe goes down there it's because 886 00:31:56,230 --> 00:31:53,679 this is a simulation of the selection 887 00:31:58,870 --> 00:31:56,240 function of sphere x so it's it's tuned 888 00:32:02,070 --> 00:31:58,880 to our sensitivity and our wavelengths 889 00:32:04,310 --> 00:32:02,080 and what we've optimized our survey for 890 00:32:06,950 --> 00:32:04,320 so now as it's getting sparser out here 891 00:32:09,750 --> 00:32:06,960 is a good time for me to turn back over 892 00:32:11,909 --> 00:32:09,760 to dita and euclid because that's where 893 00:32:13,350 --> 00:32:11,919 they start to shine and pick up where we 894 00:32:15,110 --> 00:32:13,360 left off 895 00:32:16,389 --> 00:32:15,120 yeah dina if you could hop back in here 896 00:32:17,590 --> 00:32:16,399 yeah and tell us about the euclid 897 00:32:19,750 --> 00:32:17,600 mission that you're working on this 898 00:32:22,070 --> 00:32:19,760 flyby is so cool 899 00:32:24,710 --> 00:32:22,080 yeah i'm really happy to yeah so 900 00:32:27,750 --> 00:32:24,720 basically euclid takes over about just 901 00:32:29,909 --> 00:32:27,760 about now at a redshift 0.8 and it's 902 00:32:34,389 --> 00:32:29,919 aiming to find galaxies between redshift 903 00:32:36,789 --> 00:32:34,399 about 0.8 to 1.8 and that um that that 904 00:32:38,470 --> 00:32:36,799 redshift range corresponds roughly to 905 00:32:39,909 --> 00:32:38,480 the time where dark energy was really 906 00:32:42,789 --> 00:32:39,919 just starting to become important 907 00:32:44,310 --> 00:32:42,799 kicking and kicking in and the universe 908 00:32:46,710 --> 00:32:44,320 was starting to re-accelerate its 909 00:32:49,269 --> 00:32:46,720 expansion and so euclid will be we'll be 910 00:32:51,350 --> 00:32:49,279 aiming at this range and and uh by and 911 00:32:53,430 --> 00:32:51,360 we will be looking at uh basically 912 00:32:54,230 --> 00:32:53,440 emission lines that correspond to a 913 00:32:57,029 --> 00:32:54,240 certain 914 00:32:59,190 --> 00:32:57,039 quantum transition in hydrogen and that 915 00:33:01,110 --> 00:32:59,200 happens to fall in the lab it falls into 916 00:33:02,789 --> 00:33:01,120 the visible part of the spectrum but 917 00:33:04,230 --> 00:33:02,799 when once you get redshift once you get 918 00:33:07,029 --> 00:33:04,240 the universe expanding and looking at 919 00:33:08,389 --> 00:33:07,039 these galaxies these this this feature 920 00:33:10,470 --> 00:33:08,399 this part of the fingerprint in the 921 00:33:12,310 --> 00:33:10,480 spectrum of galaxies gets redshifted 922 00:33:14,950 --> 00:33:12,320 into into the near infrared and that's 923 00:33:17,430 --> 00:33:14,960 why euclid um has one of the two 924 00:33:19,350 --> 00:33:17,440 instruments is an infrared uh instrument 925 00:33:21,669 --> 00:33:19,360 but generally euclid looks a little bit 926 00:33:23,029 --> 00:33:21,679 different to spherics uh the 927 00:33:26,549 --> 00:33:23,039 configuration is a little bit more 928 00:33:29,269 --> 00:33:26,559 familiar um and it will also be orbiting 929 00:33:31,750 --> 00:33:29,279 uh much further away from earth so if 930 00:33:35,190 --> 00:33:31,760 you show the next graphic that we have 931 00:33:37,990 --> 00:33:35,200 you'll see that the uh the the euclid's 932 00:33:39,430 --> 00:33:38,000 spacecraft will we will be sending it uh 933 00:33:42,149 --> 00:33:39,440 to something called the second 934 00:33:44,710 --> 00:33:42,159 lagrangian point of the sun earth system 935 00:33:46,710 --> 00:33:44,720 uh which is about uh just under a 936 00:33:48,710 --> 00:33:46,720 million miles away from earth so far 937 00:33:51,590 --> 00:33:48,720 outside the moon's orbit around the 938 00:33:53,350 --> 00:33:51,600 earth and it will be will be orbiting um 939 00:33:55,590 --> 00:33:53,360 the earth and the sun simultaneously at 940 00:33:57,110 --> 00:33:55,600 that point and the point the reason why 941 00:33:58,950 --> 00:33:57,120 we want to go to the second lagrangian 942 00:34:00,070 --> 00:33:58,960 point is it's it's a particularly stable 943 00:34:02,630 --> 00:34:00,080 point 944 00:34:03,750 --> 00:34:02,640 in the sun earth system uh and 945 00:34:05,830 --> 00:34:03,760 the reason why that's important is 946 00:34:08,629 --> 00:34:05,840 because you need if you go there you 947 00:34:10,149 --> 00:34:08,639 need less fuel um to to correct your 948 00:34:11,589 --> 00:34:10,159 orbit because obviously the amount of 949 00:34:13,190 --> 00:34:11,599 fuel is limited because this thing is 950 00:34:16,069 --> 00:34:13,200 very far away so like there's a gas 951 00:34:17,589 --> 00:34:16,079 station there a hydrazine gas station so 952 00:34:18,950 --> 00:34:17,599 so of course we want to conserve fuel 953 00:34:21,430 --> 00:34:18,960 and that's why it's important to go to 954 00:34:24,470 --> 00:34:21,440 one of these stable points um and so the 955 00:34:26,149 --> 00:34:24,480 spacecraft itself um will look i have a 956 00:34:27,589 --> 00:34:26,159 little graphic that will show you what 957 00:34:29,990 --> 00:34:27,599 the spacecraft will look like this is 958 00:34:32,470 --> 00:34:30,000 cgi but it almost already looks like 959 00:34:34,389 --> 00:34:32,480 this in fact the um the payload module 960 00:34:35,909 --> 00:34:34,399 just arrived to italy this week 961 00:34:37,589 --> 00:34:35,919 where it's being assembled together into 962 00:34:39,909 --> 00:34:37,599 the full spacecraft that you see 963 00:34:41,109 --> 00:34:39,919 spinning on your screen so this is what 964 00:34:43,109 --> 00:34:41,119 you could look like so you have this 965 00:34:44,550 --> 00:34:43,119 cylindrical part on that's on top now 966 00:34:46,710 --> 00:34:44,560 that's the telescope part it's a 967 00:34:50,629 --> 00:34:46,720 reflector telescope it has three mirrors 968 00:34:53,030 --> 00:34:50,639 and the primary mirror um is 1.2 meters 969 00:34:55,589 --> 00:34:53,040 in in width which i guess is about four 970 00:34:57,510 --> 00:34:55,599 foot um and so so there's a telescope 971 00:34:59,829 --> 00:34:57,520 part and then the middle part is a 972 00:35:01,589 --> 00:34:59,839 so-called focal plane where the light 973 00:35:03,670 --> 00:35:01,599 from the telescope will focus and it 974 00:35:05,109 --> 00:35:03,680 contains two instruments one is a 975 00:35:07,349 --> 00:35:05,119 visible light instrument that i'm not 976 00:35:09,750 --> 00:35:07,359 talking about today and it's just it's a 977 00:35:11,270 --> 00:35:09,760 made up of similar chips to um the 978 00:35:13,349 --> 00:35:11,280 detector chips that you might have in 979 00:35:15,190 --> 00:35:13,359 your in your camera phone and then you 980 00:35:17,829 --> 00:35:15,200 have a near infrared detector it's also 981 00:35:19,670 --> 00:35:17,839 just an array of 4x4 chips 982 00:35:21,750 --> 00:35:19,680 and then at the very bottom 983 00:35:22,870 --> 00:35:21,760 or at the very top right now is the 984 00:35:25,349 --> 00:35:22,880 so-called 985 00:35:27,349 --> 00:35:25,359 service module which contains a computer 986 00:35:29,109 --> 00:35:27,359 and the fuel tanks and that computer 987 00:35:30,790 --> 00:35:29,119 basically controls where the telescope 988 00:35:33,750 --> 00:35:30,800 is pointing and it's also talking to 989 00:35:36,470 --> 00:35:33,760 earth it's talking uh through um three 990 00:35:39,270 --> 00:35:36,480 main really big antennas in argentina 991 00:35:40,790 --> 00:35:39,280 australia and and spain so that you know 992 00:35:42,310 --> 00:35:40,800 as the earth spins we can stay in 993 00:35:44,550 --> 00:35:42,320 contact if we need to and then you have 994 00:35:46,710 --> 00:35:44,560 of course this flat bit on the side i 995 00:35:48,230 --> 00:35:46,720 guess on that side for you where that's 996 00:35:49,430 --> 00:35:48,240 the solar panels basically which and 997 00:35:52,230 --> 00:35:49,440 it's also a 998 00:35:53,829 --> 00:35:52,240 shield that shields um the telescope and 999 00:35:55,670 --> 00:35:53,839 electronics from solar radiation which 1000 00:35:57,750 --> 00:35:55,680 might heat it up but it also of course 1001 00:35:59,829 --> 00:35:57,760 powers some of the electronics so the 1002 00:36:01,670 --> 00:35:59,839 two instruments in the focal plane will 1003 00:36:02,790 --> 00:36:01,680 be taking images of the sky through the 1004 00:36:05,030 --> 00:36:02,800 by collecting the light through the 1005 00:36:06,310 --> 00:36:05,040 telescope and let me show you what those 1006 00:36:08,790 --> 00:36:06,320 images might look like so if you show 1007 00:36:10,390 --> 00:36:08,800 the next picture that i have for you so 1008 00:36:12,550 --> 00:36:10,400 in the near infrared instrument we'll be 1009 00:36:13,990 --> 00:36:12,560 taking you know images in the infrared 1010 00:36:16,150 --> 00:36:14,000 with three different filters will just 1011 00:36:18,069 --> 00:36:16,160 be fields of galaxies but then there 1012 00:36:20,069 --> 00:36:18,079 will also be a spectroscopic explosion 1013 00:36:22,069 --> 00:36:20,079 this is called slitless spectroscopy 1014 00:36:23,910 --> 00:36:22,079 where the light from all the sources in 1015 00:36:26,310 --> 00:36:23,920 the field of view will be going through 1016 00:36:27,510 --> 00:36:26,320 kind of a glorified prism and these 1017 00:36:29,829 --> 00:36:27,520 little lines that you see in this 1018 00:36:31,270 --> 00:36:29,839 picture are basically the spectra of 1019 00:36:33,430 --> 00:36:31,280 distant galaxies which are the little 1020 00:36:35,270 --> 00:36:33,440 ones and then the very saturated spectra 1021 00:36:36,950 --> 00:36:35,280 of the of the stars in our milky way 1022 00:36:40,390 --> 00:36:36,960 galaxy which we don't care about in this 1023 00:36:41,750 --> 00:36:40,400 particular uh context um and so and so 1024 00:36:43,349 --> 00:36:41,760 the really tricky thing here is that 1025 00:36:45,349 --> 00:36:43,359 your field of view is going to be full 1026 00:36:48,230 --> 00:36:45,359 of all these overlapping spectra and 1027 00:36:49,750 --> 00:36:48,240 that's that will create you know a trick 1028 00:36:51,990 --> 00:36:49,760 it means that we need to use very 1029 00:36:54,710 --> 00:36:52,000 sophisticated data analysis methods to 1030 00:36:56,870 --> 00:36:54,720 extract those spectra those emission 1031 00:36:58,069 --> 00:36:56,880 lines and those redshifts and so one of 1032 00:37:00,230 --> 00:36:58,079 the ways we're going to do that which is 1033 00:37:01,030 --> 00:37:00,240 basically the simplest way is to have um 1034 00:37:05,270 --> 00:37:01,040 these 1035 00:37:06,870 --> 00:37:05,280 we're going to mount them in the 1036 00:37:08,230 --> 00:37:06,880 telescope several different ones at 1037 00:37:10,230 --> 00:37:08,240 different angles so that this picture 1038 00:37:12,230 --> 00:37:10,240 will be rotated and it will be easier to 1039 00:37:13,670 --> 00:37:12,240 disentangle this different spectra but 1040 00:37:15,910 --> 00:37:13,680 also we've been building you know for 1041 00:37:17,589 --> 00:37:15,920 years uh tens and hundreds of people 1042 00:37:19,430 --> 00:37:17,599 have been building this sophisticated 1043 00:37:21,990 --> 00:37:19,440 software pipeline to extract all of 1044 00:37:24,710 --> 00:37:22,000 these really tricky things and so we'll 1045 00:37:26,870 --> 00:37:24,720 get spectra we'll get spectra 1046 00:37:29,270 --> 00:37:26,880 of tens of millions of galaxies all 1047 00:37:31,430 --> 00:37:29,280 across the extra galactic sky 1048 00:37:33,349 --> 00:37:31,440 and we will also make three-dimensional 1049 00:37:35,349 --> 00:37:33,359 maps using this spectra and we will 1050 00:37:37,510 --> 00:37:35,359 statistically statistically extract 1051 00:37:40,230 --> 00:37:37,520 those acoustic bubbles and and connect 1052 00:37:42,630 --> 00:37:40,240 redshift to distances that way and so we 1053 00:37:44,950 --> 00:37:42,640 will make we will try to reproduce 1054 00:37:47,190 --> 00:37:44,960 um what hubble did a hundred years ago 1055 00:37:48,950 --> 00:37:47,200 and hopefully do something a little bit 1056 00:37:50,630 --> 00:37:48,960 better than that and so let me show you 1057 00:37:52,470 --> 00:37:50,640 what hubble did 100 years ago if you see 1058 00:37:54,150 --> 00:37:52,480 that if you look at the next 1059 00:37:56,069 --> 00:37:54,160 picture that's actually hubble's plot 1060 00:37:57,430 --> 00:37:56,079 from his paper where he plotted velocity 1061 00:37:59,589 --> 00:37:57,440 against distance and velocity 1062 00:38:01,510 --> 00:37:59,599 corresponds to redshift and you see this 1063 00:38:03,349 --> 00:38:01,520 line of increasing velocity with 1064 00:38:05,430 --> 00:38:03,359 distance of course he 1065 00:38:06,790 --> 00:38:05,440 got the numbers quite wrong but the 1066 00:38:08,790 --> 00:38:06,800 trend was still there we know the 1067 00:38:10,550 --> 00:38:08,800 universe is expanding and so if you zoom 1068 00:38:12,150 --> 00:38:10,560 out massively now you get a plot like 1069 00:38:14,710 --> 00:38:12,160 this which is what we're doing nowadays 1070 00:38:15,990 --> 00:38:14,720 in cosmology and so it's not just euclid 1071 00:38:17,430 --> 00:38:16,000 there's been several experiments that 1072 00:38:19,670 --> 00:38:17,440 have been trying to to make this 1073 00:38:21,349 --> 00:38:19,680 connection and so there's been several 1074 00:38:22,790 --> 00:38:21,359 ground-based experiments and their 1075 00:38:24,069 --> 00:38:22,800 results um 1076 00:38:26,150 --> 00:38:24,079 specifically to do with redshift 1077 00:38:28,630 --> 00:38:26,160 distance relation uh i've put on this 1078 00:38:30,630 --> 00:38:28,640 plot with the colorful single dots and 1079 00:38:32,710 --> 00:38:30,640 then i've shown you what we think euclid 1080 00:38:34,950 --> 00:38:32,720 will do and how it will fill this gap in 1081 00:38:36,710 --> 00:38:34,960 distance and redshift with very very 1082 00:38:38,470 --> 00:38:36,720 small error bars that you can't even see 1083 00:38:40,470 --> 00:38:38,480 because they're hiding behind the points 1084 00:38:42,470 --> 00:38:40,480 and so this is what you will do and so 1085 00:38:44,310 --> 00:38:42,480 i've put on here what 1086 00:38:46,550 --> 00:38:44,320 what experiments have done so far and 1087 00:38:48,870 --> 00:38:46,560 what euclid will might do and but i've 1088 00:38:50,470 --> 00:38:48,880 also put four four lines on here and 1089 00:38:52,310 --> 00:38:50,480 these lines they correspond to different 1090 00:38:53,670 --> 00:38:52,320 universes different types of universe 1091 00:38:55,510 --> 00:38:53,680 that we might live in 1092 00:38:57,510 --> 00:38:55,520 and you can see that even already all 1093 00:39:00,390 --> 00:38:57,520 the data that exist is lying very close 1094 00:39:03,030 --> 00:39:00,400 to this solid line and this solid line 1095 00:39:05,589 --> 00:39:03,040 corresponds to a universe that is only 1096 00:39:07,829 --> 00:39:05,599 five percent made of regular matter that 1097 00:39:12,390 --> 00:39:07,839 we're made of so called baryonic matter 1098 00:39:15,589 --> 00:39:12,400 25 of it is made of dark matter and 70 1099 00:39:17,829 --> 00:39:15,599 of the universe is made of dark energy 1100 00:39:19,670 --> 00:39:17,839 and that's what all the data is pointing 1101 00:39:21,349 --> 00:39:19,680 at and we that's what we're trying to do 1102 00:39:23,589 --> 00:39:21,359 we're trying to to do with euclid and 1103 00:39:25,670 --> 00:39:23,599 with spherics and with with all these 1104 00:39:28,310 --> 00:39:25,680 different experiments is try to 1105 00:39:30,310 --> 00:39:28,320 really um get this data really really 1106 00:39:32,630 --> 00:39:30,320 precisely make these lines really really 1107 00:39:35,030 --> 00:39:32,640 precisely and try to understand 1108 00:39:36,550 --> 00:39:35,040 all the properties of dark energy and 1109 00:39:38,230 --> 00:39:36,560 how it impacts the 1110 00:39:39,910 --> 00:39:38,240 accelerated expansion in the universe 1111 00:39:41,990 --> 00:39:39,920 and of course of inflation in the case 1112 00:39:44,150 --> 00:39:42,000 of spherex and try to understand what 1113 00:39:45,750 --> 00:39:44,160 that implies about fundamental physics 1114 00:39:48,069 --> 00:39:45,760 and i personally am really excited about 1115 00:39:50,870 --> 00:39:49,910 thank you so much dita that is just so 1116 00:39:53,190 --> 00:39:50,880 cool 1117 00:39:54,950 --> 00:39:53,200 um so let's bring phil back and then 1118 00:39:56,950 --> 00:39:54,960 just let me mention 1119 00:39:59,190 --> 00:39:56,960 as of now euclid's scheduled to launch 1120 00:40:01,109 --> 00:39:59,200 in a little over a year at spherex in 1121 00:40:03,990 --> 00:40:01,119 just a few years and i also wanted to 1122 00:40:06,150 --> 00:40:04,000 note that as many of you that uh are 1123 00:40:07,750 --> 00:40:06,160 familiar with nasa may already know all 1124 00:40:11,670 --> 00:40:07,760 of this data is 1125 00:40:15,270 --> 00:40:11,680 will be publicly available 1126 00:40:16,710 --> 00:40:15,280 yeah so uh yeah i mean i think um 1127 00:40:19,109 --> 00:40:16,720 i hope we conveyed some of our 1128 00:40:20,309 --> 00:40:19,119 excitement for this upcoming uh you know 1129 00:40:22,550 --> 00:40:20,319 missions 1130 00:40:24,069 --> 00:40:22,560 and uh you know we've concentrated data 1131 00:40:27,109 --> 00:40:24,079 and i are cosmologists and so that's 1132 00:40:28,950 --> 00:40:27,119 that's kind of our area but i think 1133 00:40:31,109 --> 00:40:28,960 what's really going to be exciting is 1134 00:40:32,630 --> 00:40:31,119 that we're shoveling all of this data 1135 00:40:34,950 --> 00:40:32,640 just out into the community the 1136 00:40:36,550 --> 00:40:34,960 astronomical community but also just the 1137 00:40:38,550 --> 00:40:36,560 the general public 1138 00:40:40,470 --> 00:40:38,560 and those data sets are going to have so 1139 00:40:42,710 --> 00:40:40,480 much information just in in the case of 1140 00:40:46,150 --> 00:40:42,720 spherex there's going to be billions of 1141 00:40:47,190 --> 00:40:46,160 galaxies with spectroscopic uh 1142 00:40:48,870 --> 00:40:47,200 data 1143 00:40:52,309 --> 00:40:48,880 hundreds of millions of main secret 1144 00:40:54,390 --> 00:40:52,319 stars hundreds of brown dwarfs and all 1145 00:40:56,230 --> 00:40:54,400 sorts of other stuff 1146 00:40:57,430 --> 00:40:56,240 euclid is going to cover supernovae 1147 00:40:59,349 --> 00:40:57,440 they're going to do gravitational 1148 00:41:03,510 --> 00:40:59,359 lensing there's going to be 1149 00:41:05,750 --> 00:41:03,520 you know millions of galaxy mergers and 1150 00:41:07,829 --> 00:41:05,760 perhaps the most exciting stuff is just 1151 00:41:09,750 --> 00:41:07,839 what we haven't even thought of yet the 1152 00:41:12,630 --> 00:41:09,760 discovery space when you do these kinds 1153 00:41:13,829 --> 00:41:12,640 of huge surveys and just you know 1154 00:41:17,190 --> 00:41:13,839 deliver 1155 00:41:20,630 --> 00:41:17,200 a really big data set out into the 1156 00:41:22,710 --> 00:41:20,640 the world of astronomers to to mine and 1157 00:41:23,910 --> 00:41:22,720 glean as much information as possible 1158 00:41:25,510 --> 00:41:23,920 out of there 1159 00:41:27,270 --> 00:41:25,520 if i had to bet right now i'd say the 1160 00:41:29,030 --> 00:41:27,280 most exciting thing 1161 00:41:30,309 --> 00:41:29,040 to come out of spherex is really 1162 00:41:31,750 --> 00:41:30,319 something that we haven't thought about 1163 00:41:34,470 --> 00:41:31,760 right now so 1164 00:41:36,470 --> 00:41:34,480 i'm really excited and i hope we we 1165 00:41:37,670 --> 00:41:36,480 conveyed our uh some of that excitement 1166 00:41:39,829 --> 00:41:37,680 to you today 1167 00:41:41,750 --> 00:41:39,839 oh yeah very cool you guys both of you 1168 00:41:43,430 --> 00:41:41,760 thank you so much um yeah it's gonna be 1169 00:41:45,829 --> 00:41:43,440 great to see like just what becomes of 1170 00:41:47,430 --> 00:41:45,839 all this great data so i think this is a 1171 00:41:49,030 --> 00:41:47,440 great time to see what kind of questions 1172 00:41:50,710 --> 00:41:49,040 we have out there so caitlin uh what are 1173 00:41:52,309 --> 00:41:50,720 you seeing out there in the in the media 1174 00:41:55,430 --> 00:41:52,319 world 1175 00:41:58,069 --> 00:41:55,440 sure um so this one is for phil 1176 00:42:01,190 --> 00:41:58,079 musical wolves on youtube asks can 1177 00:42:03,030 --> 00:42:01,200 spheric see a galaxy behind a galaxy 1178 00:42:06,550 --> 00:42:03,040 does anything block its view is it 1179 00:42:08,790 --> 00:42:06,560 possible for it to see through 1180 00:42:11,270 --> 00:42:08,800 well so it's it's uh it's it's it's an 1181 00:42:13,589 --> 00:42:11,280 interesting question and it depends on 1182 00:42:15,270 --> 00:42:13,599 the contents of the different two 1183 00:42:16,470 --> 00:42:15,280 different galaxies 1184 00:42:19,270 --> 00:42:16,480 and uh 1185 00:42:21,190 --> 00:42:19,280 and what you know what the line of sight 1186 00:42:24,470 --> 00:42:21,200 that goes through it so you know that 1187 00:42:26,150 --> 00:42:24,480 absorption features those will imprint 1188 00:42:29,030 --> 00:42:26,160 different features so if you have like a 1189 00:42:30,630 --> 00:42:29,040 background illuminating galaxy and let's 1190 00:42:32,230 --> 00:42:30,640 say you know really 1191 00:42:33,349 --> 00:42:32,240 you know young and has lots of star 1192 00:42:36,470 --> 00:42:33,359 formation 1193 00:42:38,710 --> 00:42:36,480 and um you know lots of uv so really 1194 00:42:39,750 --> 00:42:38,720 blue and then the the galaxy that's in 1195 00:42:42,069 --> 00:42:39,760 front of it 1196 00:42:44,630 --> 00:42:42,079 um you know could have lots of molecular 1197 00:42:47,030 --> 00:42:44,640 clouds and dust and stuff what you would 1198 00:42:49,670 --> 00:42:47,040 see from the background source would 1199 00:42:51,750 --> 00:42:49,680 have an absorption fingerprint from the 1200 00:42:54,390 --> 00:42:51,760 foreground source so 1201 00:42:56,829 --> 00:42:54,400 you know it's hard to disentangle those 1202 00:42:59,190 --> 00:42:56,839 we always have to deal with the 1203 00:43:01,430 --> 00:42:59,200 resolution of our you know we can only 1204 00:43:03,030 --> 00:43:01,440 measure so fine of a thing we use the 1205 00:43:06,230 --> 00:43:03,040 word confusion 1206 00:43:07,829 --> 00:43:06,240 in uh in um in astronomy but mean it 1207 00:43:10,069 --> 00:43:07,839 literally but the beauty of 1208 00:43:11,990 --> 00:43:10,079 spectroscopic is that you know if you 1209 00:43:13,750 --> 00:43:12,000 have two spectra that are on top of each 1210 00:43:16,470 --> 00:43:13,760 other and if you have a high redshift 1211 00:43:18,309 --> 00:43:16,480 galaxy and a low redshift galaxies you 1212 00:43:23,430 --> 00:43:18,319 can see by separating out the colors the 1213 00:43:27,589 --> 00:43:25,109 great 1214 00:43:29,910 --> 00:43:27,599 thank you um we have another one this 1215 00:43:31,589 --> 00:43:29,920 one's for dita um this is a good 1216 00:43:35,190 --> 00:43:31,599 question how far away does something 1217 00:43:37,430 --> 00:43:35,200 have to be for it to redshift 1218 00:43:39,430 --> 00:43:37,440 um it's not about distance really it's 1219 00:43:40,950 --> 00:43:39,440 about the 1220 00:43:43,190 --> 00:43:40,960 apparent motion of it with respect to 1221 00:43:45,750 --> 00:43:43,200 the observer but i guess you could also 1222 00:43:47,990 --> 00:43:45,760 you could be asking actually about how 1223 00:43:49,990 --> 00:43:48,000 far does the galaxy have to be in order 1224 00:43:52,230 --> 00:43:50,000 for the expansion of space to red-shift 1225 00:43:55,030 --> 00:43:52,240 it and i mean in principle that's not 1226 00:43:58,150 --> 00:43:55,040 it's not a hard limit you know it's just 1227 00:44:00,230 --> 00:43:58,160 becomes more and more red-shifted so it 1228 00:44:02,470 --> 00:44:00,240 is really about the apparent velocity 1229 00:44:04,470 --> 00:44:02,480 but uh yeah it's just that the more the 1230 00:44:06,470 --> 00:44:04,480 further you look the more it seems 1231 00:44:08,309 --> 00:44:06,480 red-shifted which has to do with the 1232 00:44:10,309 --> 00:44:08,319 expansion of the universe but of course 1233 00:44:11,910 --> 00:44:10,319 you know there are also galaxies do 1234 00:44:14,069 --> 00:44:11,920 actually move around because of gravity 1235 00:44:16,150 --> 00:44:14,079 as well so there this is actually a 1236 00:44:17,589 --> 00:44:16,160 really interesting topic that i i work 1237 00:44:18,550 --> 00:44:17,599 on but i definitely don't have time to 1238 00:44:20,470 --> 00:44:18,560 talk about it but there's something 1239 00:44:21,990 --> 00:44:20,480 called redshift space distortions which 1240 00:44:23,750 --> 00:44:22,000 means that galaxies are moving around a 1241 00:44:25,670 --> 00:44:23,760 little bit as they're kind of going with 1242 00:44:27,270 --> 00:44:25,680 the expanding space and those redshift 1243 00:44:28,790 --> 00:44:27,280 space distortions actually can tell us a 1244 00:44:30,630 --> 00:44:28,800 lot about our theories of gravity and 1245 00:44:31,829 --> 00:44:30,640 they can we can test einstein's theory 1246 00:44:34,150 --> 00:44:31,839 with that and that's also really 1247 00:44:38,870 --> 00:44:34,160 exciting 1248 00:44:41,829 --> 00:44:38,880 um i think we have time for one more 1249 00:44:44,870 --> 00:44:41,839 question um this one i i think would be 1250 00:44:46,790 --> 00:44:44,880 for phil so rey on linkedin asks how 1251 00:44:48,829 --> 00:44:46,800 fast is the universe expanding does it 1252 00:44:50,470 --> 00:44:48,839 expand at the speed of 1253 00:44:52,790 --> 00:44:50,480 light 1254 00:44:54,950 --> 00:44:52,800 so okay when we talk about so that that 1255 00:44:56,470 --> 00:44:54,960 plot that that data showed we call that 1256 00:44:59,750 --> 00:44:56,480 the hubble flow 1257 00:45:02,390 --> 00:44:59,760 and if you look at what we call h naught 1258 00:45:04,710 --> 00:45:02,400 or how fast it's expanding today 1259 00:45:08,230 --> 00:45:04,720 um it's around 1260 00:45:10,790 --> 00:45:08,240 so 67 to 70 ish 1261 00:45:11,990 --> 00:45:10,800 kilometers per second per megaparsec 1262 00:45:13,510 --> 00:45:12,000 okay so let's 1263 00:45:15,750 --> 00:45:13,520 let's let's think about that for a 1264 00:45:18,550 --> 00:45:15,760 second um it's actually a very 1265 00:45:20,630 --> 00:45:18,560 convenient unit because we think about 1266 00:45:23,030 --> 00:45:20,640 okay a megaparsec that's a huge distance 1267 00:45:26,069 --> 00:45:23,040 so let's let's just answer that question 1268 00:45:27,510 --> 00:45:26,079 at a megaparsec which is a you know a 1269 00:45:28,390 --> 00:45:27,520 distance 1270 00:45:30,630 --> 00:45:28,400 that's 1271 00:45:32,870 --> 00:45:30,640 you know pretty cosmologically far away 1272 00:45:34,710 --> 00:45:32,880 from us but that means that those 1273 00:45:38,790 --> 00:45:34,720 galaxies are basically moving away from 1274 00:45:40,470 --> 00:45:38,800 us at 70 kilometers per second at that 1275 00:45:42,309 --> 00:45:40,480 at that distance so 1276 00:45:44,390 --> 00:45:42,319 that's how far away 1277 00:45:46,470 --> 00:45:44,400 also interesting about that expansion 1278 00:45:49,109 --> 00:45:46,480 rate if we now think okay kilometers per 1279 00:45:51,270 --> 00:45:49,119 second per megaparsec okay kilometers a 1280 00:45:53,109 --> 00:45:51,280 unit of distance megaparsec is a unit of 1281 00:45:55,510 --> 00:45:53,119 distance so you can convert things 1282 00:45:57,910 --> 00:45:55,520 around and those distance cancel out and 1283 00:45:59,750 --> 00:45:57,920 then you're left with one over seconds 1284 00:46:02,069 --> 00:45:59,760 so it's an inverse time 1285 00:46:04,390 --> 00:46:02,079 if we invert that time 1286 00:46:07,109 --> 00:46:04,400 you'll get something around 14 billion 1287 00:46:10,790 --> 00:46:07,119 or 13.8 billion and that's the age of 1288 00:46:14,790 --> 00:46:12,870 wow 1289 00:46:18,390 --> 00:46:14,800 well thank you very much phil thank you 1290 00:46:20,230 --> 00:46:18,400 very much dida so folks that's about all 1291 00:46:22,309 --> 00:46:20,240 the time we have tonight so i want to 1292 00:46:23,910 --> 00:46:22,319 thank both of you dita phil thank you so 1293 00:46:25,589 --> 00:46:23,920 much caitlyn of course 1294 00:46:27,589 --> 00:46:25,599 all the folks behind the scenes and of 1295 00:46:29,910 --> 00:46:27,599 course all of you out there for tuning 1296 00:46:32,230 --> 00:46:29,920 in as caitlyn said earlier you know this 1297 00:46:33,829 --> 00:46:32,240 is your space program and this is one 1298 00:46:35,910 --> 00:46:33,839 way for you to participate in it and we 1299 00:46:37,990 --> 00:46:35,920 appreciate that so thank you 1300 00:46:40,790 --> 00:46:38,000 so please join us next month when we'll 1301 00:46:42,790 --> 00:46:40,800 talk with jpl scientist josh willis 1302 00:46:45,109 --> 00:46:42,800 about the sentinel 6 michael freilix 1303 00:46:47,990 --> 00:46:45,119 satellite's first year in space that'll 1304 00:46:53,150 --> 00:46:48,000 be a good one until then be safe and