1 00:00:00,240 --> 00:00:05,490 As you know, today we'll have a public lecture by Professor Adam Leroy from the Ohio State University. 2 00:00:05,700 --> 00:00:11,830 I would like to say a few words about the lecture. So, of course, in the physics department, we have a number of regular public lectures. 3 00:00:11,850 --> 00:00:18,480 This isn't one of them. So the star visiting lectureship is actually a program from the university that aims to bring 4 00:00:18,960 --> 00:00:25,080 American professors to the university to interact with people here to participate in the life. 5 00:00:25,830 --> 00:00:33,120 In this case, that involves Adam participating in a workshop while the college on giant molecular clouds. 6 00:00:33,120 --> 00:00:36,810 And if you don't know what this is yet, I'm sure you'll know within the next hour. 7 00:00:38,070 --> 00:00:44,400 Then we'll also meet our graduate students tomorrow. And the visiting lectureship also involves Adam giving this lecture. 8 00:00:44,700 --> 00:00:45,750 So you're most welcome. 9 00:00:46,980 --> 00:00:55,170 So Adam is a product of the University of Berkeley where he got this position focus, former supervisors saying that here on the front the ability. 10 00:00:55,170 --> 00:00:56,730 So it's a kind of a family affair. 11 00:00:58,680 --> 00:01:06,330 He went down to the Max Planck Institute of Astronomy in Heidelberg, where we have also a number of people here for the workshop. 12 00:01:06,890 --> 00:01:14,190 He done sorry was then a Hubble fellow, which is a very prestigious fellowship funded in the US through Naza, 13 00:01:14,400 --> 00:01:21,059 obviously related to the Hubble Space Telescope. So he was based at the National Radio Astronomy Observatory for a few years, 14 00:01:21,060 --> 00:01:27,570 then became a staff member there before moving to the High State University where he is now in Columbus. 15 00:01:28,020 --> 00:01:36,290 And so Adam, along with a number of people in the room, have been here for the whole week to discuss essentially what we call stellar nurseries, 16 00:01:36,300 --> 00:01:42,720 the regions where new stars are being born there, regions which by astronomy standards are very dense. 17 00:01:42,720 --> 00:01:48,180 Of course, by a common earth, standards would be essentially probably nearly perfect vacuum, 18 00:01:49,620 --> 00:01:52,290 I suspect actually better action than we can achieve in our lives. 19 00:01:52,530 --> 00:01:57,120 But by astronomy standards, there are very, very dense regions and there obviously where new stars are born. 20 00:01:57,120 --> 00:02:05,430 So Adam has made a speciality throughout his career to study these regions in both in the Milky Way and in external galaxies primarily. 21 00:02:05,730 --> 00:02:11,280 And so that involves studying essentially what we call the different phases of the interstellar medium. 22 00:02:11,280 --> 00:02:14,909 And as the name suggests, this is essentially the stuff between stars. 23 00:02:14,910 --> 00:02:19,710 So it's a kind of tenuous gaseous material that could be dense and in molecular form, 24 00:02:20,010 --> 00:02:24,690 less dense in atomic form, or perhaps also ionised when it's up to higher energies. 25 00:02:24,690 --> 00:02:30,450 And I'm sure Adam will, you know, illustrate this with a lot of pretty pictures. 26 00:02:30,450 --> 00:02:37,650 Of course, that's something astronomy is good for. But for the moment, Adam, thank you very much for the lecture and the course. 27 00:02:38,550 --> 00:02:43,920 But yeah, exactly. So thanks very much to Martin and to the invitation to speak. 28 00:02:44,940 --> 00:02:53,579 And exactly as Martin said, what I'm going to tell you about today is one of the most exciting current areas in astronomy that may get a 29 00:02:53,580 --> 00:03:01,290 little bit less airtime than some of the results from the Hubble Space Telescope and some of the space missions. 30 00:03:01,920 --> 00:03:07,800 And this area is the area of microwave astronomy or millimetre and submillimeter astronomy. 31 00:03:08,580 --> 00:03:14,370 And the reason this is so exciting is exactly as Martin says, this is a field where we've just turned on essentially the biggest, 32 00:03:14,370 --> 00:03:17,849 most complicated telescope on the ground that we have ever built. 33 00:03:17,850 --> 00:03:21,420 And this is the Atacama Large Millimetre Submillimeter Array, 34 00:03:22,350 --> 00:03:29,190 which is essentially an amazing machine to watch stars, planets and galaxies be born and grow. 35 00:03:30,030 --> 00:03:35,849 And so this is this thing turned on a few years ago and has essentially been revolutionising 36 00:03:35,850 --> 00:03:41,459 every field that it's actually able to make contributions to in the intervening time ever since. 37 00:03:41,460 --> 00:03:51,480 And it's really just getting started. So if you take nothing away from this talk except the fact that you should keep your eyes peeled and your vocal, 38 00:03:51,960 --> 00:03:58,920 your favourite news site or your local newspaper for the cool stuff that is coming out of Alma over the next year and over the next decade. 39 00:03:59,850 --> 00:04:08,280 So just by a by way of a little bit of background, when we look up and see the universe around us with our eyes, 40 00:04:08,280 --> 00:04:13,079 of course, what we see is a universe of stars that we see with our eyes, 41 00:04:13,080 --> 00:04:18,360 a few thousand of them, and a universe of galaxies just really epitomised by this picture on the right, 42 00:04:18,690 --> 00:04:21,360 which is maybe the most famous picture that Hubble has ever taken. 43 00:04:21,360 --> 00:04:27,360 And it's a wonderful picture because it really consists of pointing Hubble at the blank s part of sky that you can find, 44 00:04:27,360 --> 00:04:31,440 and just seeing the galaxies fill the universe heading out in every direction. 45 00:04:32,640 --> 00:04:41,549 But we know that these stars and fundamentally what we're seeing here is starlight have not been around for the entire history of the universe. 46 00:04:41,550 --> 00:04:46,410 The universe filled mostly full of just hydrogen and helium gas. 47 00:04:47,490 --> 00:04:53,370 And some 13.8 billion years ago, there were no stars and there were no galaxies. 48 00:04:54,450 --> 00:04:59,910 And when we take pictures of the universe shortly after this time, we see a universe full of gas and dark matter. 49 00:04:59,970 --> 00:05:08,070 But not these things. So there is a huge branch of the field of astronomy which is concerned with the question of, you know, 50 00:05:08,130 --> 00:05:12,510 how do we build the structures that we actually look around and see the stars, the galaxies? 51 00:05:12,870 --> 00:05:15,779 And increasingly, over the last decade or so, 52 00:05:15,780 --> 00:05:23,070 the planets that we know populate the orbit of the stars around us in the Milky Way and must also fill the universe. 53 00:05:23,940 --> 00:05:33,330 So the broad picture that we have, you know, we have reasonably understood, which essentially amounts to gravity winds or to some approximation, 54 00:05:33,540 --> 00:05:37,590 we know that the universe formed in the big bang form of hydrogen and helium. 55 00:05:38,490 --> 00:05:48,870 There were some initial concentrations where matter was denser and the gas that formed in the early universe flowed on to these denser peaks, 56 00:05:48,870 --> 00:05:52,440 and that flows on to these denser peaks. These things become galaxies. 57 00:05:52,800 --> 00:06:00,629 Material continues to flow in over the course of cosmic time, and the material that flows into these galaxies forms, 58 00:06:00,630 --> 00:06:07,770 stars, forms, the spinning disks of galaxies, and the material that has not yet formed into stars, 59 00:06:07,770 --> 00:06:08,420 as Martin said, 60 00:06:08,440 --> 00:06:19,050 lives between stars in a medium of hydrogen and helium and other gases that I'll mention that serve as the fuel for the next generation of stars. 61 00:06:19,890 --> 00:06:26,840 So of particular interest inside these galaxies, as gas flows in, are these very dense pockets of gas. 62 00:06:26,870 --> 00:06:30,599 So these represent the point at which gravity has won enough to collect hydrogen 63 00:06:30,600 --> 00:06:35,190 and helium into clouds that are comparatively very cold and very dense, 64 00:06:35,700 --> 00:06:40,170 where we we think that essentially all stars and planets form. 65 00:06:41,160 --> 00:06:44,490 So these stellar nurseries, which all come back to quite a few times during the talk, 66 00:06:45,420 --> 00:06:49,440 are really the places where we think that galaxies and stars are forged. 67 00:06:49,440 --> 00:06:57,060 And it turns out that Alma is a completely revolutionary machine for looking at these stellar nurseries. 68 00:06:58,050 --> 00:07:04,290 So I'm going to unpack this in various ways through the course of this talk. 69 00:07:05,310 --> 00:07:09,570 But the part the thing that I want you to take away from this very general beginning is that 70 00:07:09,570 --> 00:07:16,379 when we look up every star in every galaxy that we see ultimately formed in one of these cold, 71 00:07:16,380 --> 00:07:22,140 dense, stellar nurseries out of the gas between stars and this process is still ongoing today. 72 00:07:22,140 --> 00:07:27,000 We only need to look at the easiest constellation to find in the sky, Orion, 73 00:07:27,000 --> 00:07:34,230 in order to see the process of young, new stars being born out of a cold, extensive cloud. 74 00:07:34,560 --> 00:07:36,570 And I'll show you a picture of Orion in just a second. 75 00:07:37,710 --> 00:07:44,850 But so in general, our a huge chunk of our field is deeply concerned with this question of in detail, 76 00:07:45,150 --> 00:07:54,150 how do we actually form this material that started off as just diffuse hydrogen and helium gas into stars, planets, galaxies? 77 00:07:54,150 --> 00:08:01,260 What determines why you have a star here or this set of planets around this star, and what drives the formation of the first galaxies? 78 00:08:02,820 --> 00:08:07,320 And so this is hard or even impossible to do only with the light that you see from your eyes. 79 00:08:08,250 --> 00:08:18,480 And to see this, I really like sticking with Orion for just a second and showing how Orion looks to someone using optical light on the left, 80 00:08:18,810 --> 00:08:21,960 you may you see the familiar constellation that you can pick out with your eyes. 81 00:08:22,680 --> 00:08:28,020 And this includes the some of the young stars that are forming nearest to the sun. 82 00:08:29,190 --> 00:08:36,210 And on the right. What you see is an illustration using light at longer wavelengths to pick out. 83 00:08:36,960 --> 00:08:41,430 And I'll talk about what that means in just a second here to instead take a picture 84 00:08:41,430 --> 00:08:45,839 of the glowing gas and dust that make up the stellar nursery that actually 85 00:08:45,840 --> 00:08:54,270 pervades the constellation of Orion and is certainly serving as the engine that builds new stars and Orion and is making our Milky Way galaxy bigger. 86 00:08:54,690 --> 00:09:02,820 So the thing that you see on the right is a picture of glowing dust in galaxies is a picture of glowing dust. 87 00:09:03,600 --> 00:09:06,270 You see the same Orion constellation illustrated here. 88 00:09:06,990 --> 00:09:11,790 And what you can see is that this region that looks empty on the sky to us or dark on the sky to 89 00:09:11,790 --> 00:09:20,189 us with just a few bright young stars hanging off the belt is actually full of shining dust. 90 00:09:20,190 --> 00:09:27,120 And this dust is shining, but it's incredibly cold. It's only about 20 degrees kelvin, so just above absolute zero. 91 00:09:27,960 --> 00:09:35,820 And it's dense enough that we're able to see it glow prominently in both the light that I'm showing you here, which is the glow of dust. 92 00:09:35,820 --> 00:09:39,210 And I'll say a little bit more about what that is in a couple of slides, 93 00:09:40,020 --> 00:09:48,090 but we also see it glow and all sorts of terrible poisonous molecules that form as a result of the gas being very well shielded, 94 00:09:48,480 --> 00:09:55,260 protected from from destructive light by the dust and being dense enough to form molecules. 95 00:09:56,890 --> 00:10:08,830 So let me just for those who are who do not have a non optical astronomy background, which is almost everybody, let me just emphasise that. 96 00:10:09,220 --> 00:10:13,660 So I'm going to talk in this, I'm going to freely use the words microwave sub. 97 00:10:13,660 --> 00:10:21,730 Mm mm. Am long wavelength and all of these things just refer to observing the universe with light, 98 00:10:22,060 --> 00:10:27,730 but it's light that is lower in energy and a little bit different in character, 99 00:10:28,270 --> 00:10:30,790 meaning that it has low energy, 100 00:10:30,790 --> 00:10:37,300 it passes through things easily and it's easier to generate with cold objects than the light that we see with our eyes. 101 00:10:37,780 --> 00:10:43,420 But this this long wavelength light, which is a type of radio waves, 102 00:10:43,690 --> 00:10:49,540 travels at the speed of light and otherwise behaves just like the light that we see with our eyes. 103 00:10:50,170 --> 00:10:58,240 So the advantage for using this kind of light to study the universe is that you can see things like the very cold gas that pervades the Orion. 104 00:10:58,660 --> 00:11:07,000 The constellation of Ryan is forming these young stars. Or you can see the glow of a whole suite of terrible poisonous molecules. 105 00:11:07,750 --> 00:11:15,820 And because, as I'm sure you're familiar with, your radio waves can get inside your house and so can easily pass through intervening material. 106 00:11:16,150 --> 00:11:24,940 This also turns out to be a very good way to look through the dust that blocks the light from the stars and material deep inside the Orion Cloud. 107 00:11:27,200 --> 00:11:38,060 So hopefully this makes sense. And what we would really like to do if we want to understand how stars, galaxies, planets are born, 108 00:11:38,960 --> 00:11:45,320 is to study this long wavelength light that comes specifically from cold, dense material. 109 00:11:45,350 --> 00:11:48,830 It's about to form the next generation of stars and planets, 110 00:11:49,850 --> 00:11:54,410 and we would like to take pictures of the structures that are giving birth to these stars and planets. 111 00:11:55,160 --> 00:11:59,360 To do this, we need to be able to catch this light. We need to build telescopes that see this type of light. 112 00:12:00,290 --> 00:12:06,319 And what these essentially look like are giant versions of the satellite antennas that you may have on your 113 00:12:06,320 --> 00:12:14,570 home to to catch a television or versions of the communication devices that you may see driving around. 114 00:12:15,560 --> 00:12:24,020 But these things need to be able to see through the Earth's atmosphere, which is unfortunately very, 115 00:12:24,020 --> 00:12:32,929 very opaque to the type of the particular type of light that we get from dust grains and molecules 116 00:12:32,930 --> 00:12:38,060 that are exactly the things that are forming the next generation of stars and galaxies. 117 00:12:38,960 --> 00:12:48,530 So the specific problem, which is not exactly the same thing, but is sort of related, is that water in the atmosphere blocks microwaves, 118 00:12:48,530 --> 00:12:55,670 which you might know, although this is a this is a plane a little fast and loose from the fact that your microwave oven heats the water in your food. 119 00:12:56,900 --> 00:13:02,930 So the water in the atmosphere in particular makes the atmosphere very, very opaque to seeing this light. 120 00:13:03,170 --> 00:13:10,520 But we can see it from the ground and in particular, we can see this glow of cold gas and dust. 121 00:13:10,940 --> 00:13:18,080 If we can get up to a site that is high enough and dry enough that a substantial fraction of the water in the atmosphere is below our telescopes. 122 00:13:18,800 --> 00:13:26,660 And you can see that illustrated here in this sketch of how opaque the atmosphere is as a function of the wavelength of light that you're looking at. 123 00:13:26,660 --> 00:13:30,410 And in particular, if you wanted to study, glowing planets are glowing, 124 00:13:30,410 --> 00:13:36,440 forming a glowing planet, forming disks or star forming clouds, stellar nurseries. 125 00:13:36,770 --> 00:13:42,530 You would want to be looking here. And so you can see you can see through the atmosphere a little bit, but it's not great. 126 00:13:43,130 --> 00:13:51,440 So what you like to do is you'd like to go to a very high and very dry site in order to study this type of light. 127 00:13:51,590 --> 00:13:55,010 And this is what people have been doing for years. 128 00:13:55,370 --> 00:14:01,280 So they built arrays of telescopes on places like the top of Monaco, up in the Alps in France. 129 00:14:02,060 --> 00:14:04,370 And as you can imagine, this is very, very difficult. 130 00:14:05,510 --> 00:14:13,640 So what that means is that to date, we have not had truly giant telescopes studying the universe in microwave light. 131 00:14:14,060 --> 00:14:18,260 And so this is where the Atacama Large Millimetre Submillimeter array comes in. 132 00:14:18,590 --> 00:14:22,280 So this really blows the door off this field by essentially giving us our first. 133 00:14:22,730 --> 00:14:27,290 You can think of this as a Hubble class instrument to study the universe in microwave light. 134 00:14:28,400 --> 00:14:33,290 And so as I mentioned at the beginning of the talk by several metrics, this is the biggest, most complicated. 135 00:14:34,100 --> 00:14:40,310 And although this shouldn't necessarily be a point of pride, most expensive telescope ever built on the ground. 136 00:14:41,180 --> 00:14:50,180 And so the idea is that the reality is that Alma is observing the universe in microwave light with both a sensitivity and 137 00:14:50,180 --> 00:14:56,840 a sharpness of view that is essentially ten times better than any previous telescope studying the universe in this way. 138 00:14:57,830 --> 00:15:01,550 So to give a couple of specifics and then I will show you a couple more pictures. 139 00:15:02,210 --> 00:15:13,130 Alma is an array of 66 antennas. So these things have all been so they're individually about 12 metres across and they've all been carefully machine 140 00:15:13,130 --> 00:15:19,850 so that the surface accuracy of the thing is almost a perfect parabola to within something like ten microns. 141 00:15:20,660 --> 00:15:26,450 And behind this array of 66 antennas is a massive supercomputer that in real time combines what 142 00:15:26,450 --> 00:15:32,600 all of the individual antennas see and gives us these fantastic pictures of the universe. 143 00:15:33,440 --> 00:15:35,150 And this would be impressive on its own. 144 00:15:35,750 --> 00:15:43,200 But the really impressive thing is that this fantastic collection of machinery doesn't live just anywhere but live. 145 00:15:43,230 --> 00:15:49,670 So I said that we want to place the telescopes that study this microwave emission in places that are high and dry. 146 00:15:49,910 --> 00:15:54,620 And Alma essentially picks out the place that the place where you could build 147 00:15:54,620 --> 00:15:57,980 an array that is highest and driest without heading down to the South Pole. 148 00:15:58,370 --> 00:16:03,829 So Alma is built high in the Chilean Andes. So as part of the Atacama Desert specifically, it's on the charge. 149 00:16:03,830 --> 00:16:10,879 We're on to our plateau, which is a flat enough piece of ground at an elevation of 5000 metres so that you 150 00:16:10,880 --> 00:16:15,140 can both build an array and be above an enormous fraction of the Earth's atmosphere, 151 00:16:15,440 --> 00:16:21,259 meaning that the light from the forming planets and stars and galaxies is not blocked 152 00:16:21,260 --> 00:16:26,060 out by nearly as much of the atmosphere as it would be if you built these telescopes. 153 00:16:26,170 --> 00:16:28,630 At lower elevations. And you can see your comparison here. 154 00:16:29,450 --> 00:16:36,490 Alma is although there are smaller telescopes at higher elevation, Alma is really the highest big telescope in the world. 155 00:16:37,570 --> 00:16:41,740 So you have this fantastic machine in a high and dry place. 156 00:16:41,740 --> 00:16:44,020 And I said that it takes very, very sharp pictures. 157 00:16:44,770 --> 00:16:51,670 I do want to emphasise that this array isn't just 66 individual antennas all doing their own thing. 158 00:16:51,700 --> 00:16:58,830 Instead, when you. One of the neat things about using this particular type of light is that when you see these arrays of dishes, 159 00:16:58,840 --> 00:17:03,700 but you also see pictures of they're all staring in the same direction for a reason because 160 00:17:03,700 --> 00:17:09,250 essentially these 66 antennas are all able to work at the same time as part of a bigger, 161 00:17:09,280 --> 00:17:15,790 single, coherent telescope. There are some pluses and minuses to doing things this way, but it's a little bit like taking a metre, 162 00:17:16,000 --> 00:17:19,950 scattering it and saying that you can still see the reflection in the mirror. 163 00:17:20,380 --> 00:17:24,370 And it's really like imagining that you've built a great big telescope that has 164 00:17:24,370 --> 00:17:29,140 the size equal to the area under which you've scattered all of these antennas, 165 00:17:29,530 --> 00:17:33,759 and then saying that I'm going to just knock out most of the area in there. 166 00:17:33,760 --> 00:17:38,860 And it turns out that with a little bit of math, which is done by that supercomputer that I mentioned, 167 00:17:39,250 --> 00:17:46,120 you can then still use this essentially sparsely sampled version of a single giant telescope to take 168 00:17:46,120 --> 00:17:51,070 pictures that are just as sharp as they would if you had a telescope that was not 12 metres in size, 169 00:17:51,520 --> 00:17:59,860 but a kilometre. Or when you throw these things out to the maximum distance afforded by this plateau, a telescope that's 15 kilometres in size. 170 00:18:00,640 --> 00:18:08,170 So the trick here is to drag a whole bunch of very, very precise, individually awesome telescopes up to 5000 metres, 171 00:18:08,170 --> 00:18:15,819 find a piece of ground that is flat enough to spread them all out across ten kilometres and then attach a computer that when it was built and this is, 172 00:18:15,820 --> 00:18:23,170 you know, Warsaw calls this but when it was built was one of the most impressive pieces of computing hardware in the world. 173 00:18:23,170 --> 00:18:29,650 Attach this to the back of it to get them all working together as a single telescope that gives you these incredibly sharp images. 174 00:18:31,860 --> 00:18:38,490 So the idea then is that you have this group of telescopes working as an array 175 00:18:39,090 --> 00:18:44,100 with a size that is effectively between as much as 15 kilometres across. 176 00:18:44,730 --> 00:18:51,030 And let me just say in a little bit more detail quickly, what you can actually use this fantastic piece of machinery to see. 177 00:18:51,420 --> 00:18:55,260 So I was a little glib in the beginning and said Forming stars, forming galaxies. 178 00:18:55,920 --> 00:18:59,130 So I'm specifically really good at looking at two things. 179 00:18:59,280 --> 00:19:03,270 There are some it can do quite a few other things, but it's really good at doing two things. 180 00:19:03,720 --> 00:19:07,740 And so the first of these is looking at the glow of interstellar dust. 181 00:19:08,280 --> 00:19:11,700 So there, as Martin mentioned, there's this. 182 00:19:12,480 --> 00:19:15,990 If you go out into the Milky Way galaxy and you move between stars, 183 00:19:16,260 --> 00:19:21,270 that space is not totally empty, although it's it is quite empty by terrestrial standards. 184 00:19:21,930 --> 00:19:30,840 It's instead full of hydrogen and helium, but also other things carbon, oxygen, the heavy elements that make up our body and the earth. 185 00:19:31,290 --> 00:19:41,849 And a lot of those heavy things live in tiny, little sooty grains that are maybe a millionth of a metre across and that what we call dust, 186 00:19:41,850 --> 00:19:47,669 but with a look more like soot, if you can put it on your fingers. So that soot lives between the stars. 187 00:19:47,670 --> 00:19:52,320 And it's the reason that interstellar clouds look dark and starlight. 188 00:19:52,330 --> 00:19:56,340 If you've ever seen a picture of the Milky Way, you've seen these dark lanes running through it. 189 00:19:56,370 --> 00:20:00,210 This is you can see this in the first light that I showed. 190 00:20:01,770 --> 00:20:05,489 And so that that dust blocks out the light of stars that hits it. 191 00:20:05,490 --> 00:20:09,180 But that energy can't go nowhere. So instead, the dust heats up. 192 00:20:09,180 --> 00:20:15,480 Although it's by no means hot, it heats up to temperatures of something like 20 degrees above absolute zero, 193 00:20:15,900 --> 00:20:22,890 but something that's 20 degrees above absolute zero. It turns out to be really good at glowing in the type of light that Alma can see. 194 00:20:23,130 --> 00:20:29,790 So almost very good at snapping pictures like this where you look at the glow of the dust between stars. 195 00:20:29,790 --> 00:20:39,899 And so you also see the gas between stars. And it turns out that the stellar nurseries that form stars are huge condensation of interstellar dust. 196 00:20:39,900 --> 00:20:48,090 And so Alma turns out to be very good at looking at the structures that form stars and planets, because they tend to be full of interstellar dust. 197 00:20:49,140 --> 00:20:53,310 So the other thing it does is it looks at gases that will mostly kill you. 198 00:20:54,570 --> 00:21:01,080 So in these very dense regions that are likely in interstellar space, that are likely to form the next stars and planets, 199 00:21:01,500 --> 00:21:09,360 that hydrogen and helium isn't just floating around by itself, it's floating around and it is bumping into other atoms. 200 00:21:09,750 --> 00:21:17,790 And as it does this, these regions are dense enough and cold enough, and they are protected from the kind of light that when bust molecules apart. 201 00:21:18,180 --> 00:21:24,870 And so these atoms combine into molecules and these molecules are things like carbon monoxide, cyanide, 202 00:21:24,870 --> 00:21:30,110 formaldehyde, ammonia, basically nothing that you would like to actually be locked in a room with. 203 00:21:30,120 --> 00:21:38,400 But this is it turns out that these things are pervasive in interstellar space and Alma is very, very good at seeing them. 204 00:21:38,820 --> 00:21:46,380 So at this point, there are between 102 hundred total molecules known in interstellar space, with more of them being seen every year. 205 00:21:47,220 --> 00:21:49,870 And in addition to being able to see the dust between stars. 206 00:21:49,890 --> 00:21:57,600 Alma is very good at picking out the molecules that live in the densest and darkest parts of interstellar interstellar space. 207 00:21:59,280 --> 00:22:03,960 And I will force a little bit of quantum mechanics on you to tell you why it's very good at seeing this. 208 00:22:05,160 --> 00:22:10,620 So these molecules can spin and vibrate and in particular when they spin. 209 00:22:10,980 --> 00:22:15,660 So when you will take the example of carbon monoxide here, when one of these molecules spins, 210 00:22:15,990 --> 00:22:21,389 it turns out that quantum mechanics says you're only allowed to spin at certain rates and is you 211 00:22:21,390 --> 00:22:25,680 shift the spin of the molecule from a faster spinning molecule to a lower spinning molecule. 212 00:22:27,180 --> 00:22:31,470 You drop the overall energy of the molecule. And again, that energy has to go somewhere. 213 00:22:31,800 --> 00:22:36,900 And where it goes is out in light with a very specific wavelength or frequency, 214 00:22:36,900 --> 00:22:43,260 one that we know for simple molecules like this very well from either calculations or the laboratory. 215 00:22:44,010 --> 00:22:48,780 And it turns out that the type of light that's emitted by all of these terrible interstellar 216 00:22:48,780 --> 00:22:56,130 molecules lines up exactly in the range of types of light that Alma is very good at catching. 217 00:22:56,460 --> 00:23:03,030 So Alma is excellent at taking pictures of the molecules that pervade the densest and coldest parts of interstellar space. 218 00:23:03,990 --> 00:23:10,070 And so you get pictures like this, which is a picture of a very nearby nursery that's currently forming stars. 219 00:23:10,080 --> 00:23:18,930 The total image is a few tens of light years across. I'll show that again in a couple of slides and you can see all sorts of fantastic 220 00:23:18,930 --> 00:23:23,220 structure and figure out why the next generations of stars are being born. 221 00:23:23,970 --> 00:23:29,280 You'll also notice that this image is coloured with blue and green and red colours. 222 00:23:29,280 --> 00:23:31,469 So that's actually showing you the third thing. 223 00:23:31,470 --> 00:23:38,230 And the last thing that I'll mention that Alma is very good at measuring, which is how fast that gas is moving towards us or away from us. 224 00:23:38,700 --> 00:23:42,909 And so I mentioned that that light comes out with a very specific frequency. 225 00:23:42,910 --> 00:23:46,319 And so the molecules are only allowed to spin at certain rates. 226 00:23:46,320 --> 00:23:49,320 And we know exactly the type of light that's emitted. 227 00:23:49,800 --> 00:23:53,850 So you're familiar with the Doppler effect from everyday life, 228 00:23:53,850 --> 00:24:00,450 as this is the effect where an ambulance giving off a particular frequency as it comes towards you, 229 00:24:00,450 --> 00:24:04,050 you hear it higher pitched and as it moves away from you, you hear it lower pitched. 230 00:24:04,650 --> 00:24:08,549 So there's many applications of this in everyday life. Exactly. 231 00:24:08,550 --> 00:24:11,510 The same thing goes on with light from these poisonous molecules. 232 00:24:12,300 --> 00:24:19,709 So as a carbon monoxide molecule moves towards you, you see the light from it at a slightly higher frequency. 233 00:24:19,710 --> 00:24:22,950 And as it moves away from you, you see it at a slightly lower frequency. 234 00:24:23,490 --> 00:24:29,250 So the result is that whenever Alma takes a picture of one of these regions 235 00:24:29,250 --> 00:24:34,920 that are forming stars or planets in it and looks at one of these molecules, 236 00:24:34,920 --> 00:24:38,610 we actually learn about the motions of the gas as it comes towards or away from us. 237 00:24:39,000 --> 00:24:47,760 And this also makes it a very effective machine to, for example, try to weigh things or watch the motions induced by gravity. 238 00:24:48,150 --> 00:24:51,480 And so I'll show you a couple of examples of that later on. 239 00:24:53,650 --> 00:24:59,590 So let me now shift gears to tell you a little bit about what we've actually found. 240 00:24:59,620 --> 00:25:03,130 So I mentioned that Alma has been sort of blowing the doors off of a number of fields. 241 00:25:03,490 --> 00:25:11,740 And so I just want to take you through a few of the things that have been done and maybe about to be done that I think are most exciting. 242 00:25:11,770 --> 00:25:21,009 And so the first of these is that the formation of planets, I would say, is the most exciting results on the formation of planets that we've had. 243 00:25:21,010 --> 00:25:30,460 And I will probably not even slightly exaggerate in decades have come from pointing Alma at the places where we know that planets actually form. 244 00:25:30,820 --> 00:25:37,930 So these are two artist's conceptions. So the idea that we have in our head and this goes back to contain the 18th century, 245 00:25:38,620 --> 00:25:42,910 is that the solar system forms out of a spinning disk of gas and dust, 246 00:25:43,360 --> 00:25:49,330 and these spinning disks of gas and dust formed naturally as a result of this sort of collapse of gas down the form of the sun. 247 00:25:50,440 --> 00:25:58,000 And if you've seen pictures of the solar system, you see that the planets are all more or less aligned in a plane spinning in the same direction. 248 00:25:58,630 --> 00:26:05,790 So we have quite good indirect evidence for this idea that planets are forming out of disks around young stars. 249 00:26:05,800 --> 00:26:12,730 And then over the last decades, we've been able to see but not take sharp images of the disks that we think form planets. 250 00:26:13,840 --> 00:26:22,690 And what Alma has brought to the table for the first time is the knowledge, not just that there are disks forming planets around young stars, 251 00:26:23,020 --> 00:26:27,820 but the ability to actually take detailed pictures of the places where planets form. 252 00:26:28,270 --> 00:26:33,579 And so for a lot of astronomers and not only people who are aficionados of arrays of telescopes, 253 00:26:33,580 --> 00:26:42,550 some young may find this picture here on the right, which is a picture of a the planet forming disk around HL 12. 254 00:26:43,450 --> 00:26:48,340 So this is a nearby very young so less than a million years, 255 00:26:48,580 --> 00:26:57,310 potentially just a couple of hundred hundreds of thousands of years old star with one of the brightest disks that we have available to us in the sky. 256 00:26:57,340 --> 00:27:00,430 So this is the planet forming disk around a very young star. 257 00:27:00,460 --> 00:27:02,800 What you're looking at is the glow of the dust that I mentioned. 258 00:27:03,340 --> 00:27:09,130 And instead of just being able to tell if there's a disk there, you see the stunning structural gaps and bright spots, 259 00:27:10,090 --> 00:27:15,220 which is almost certainly directly related to the formation of planets in this disc. 260 00:27:15,910 --> 00:27:20,080 The initial thought was that perhaps planets were clearing out the rings in this disk. 261 00:27:20,080 --> 00:27:25,060 At this point, people have looked and are able to rule out planets within some of these gaps. 262 00:27:25,690 --> 00:27:29,530 And so some of the current thinking is that instead what you're watching is the formation 263 00:27:29,530 --> 00:27:34,240 of the thick rings of dust that will potentially form future generations of planets. 264 00:27:35,320 --> 00:27:43,420 But in either case, the stunning thing here is that you have a snapshot of the birthplace of planets that has sharper you know, 265 00:27:43,480 --> 00:27:46,510 that is sharper and more detailed than anything we've had before. 266 00:27:47,380 --> 00:27:54,610 And in many ways, as much this image is much more beautiful than these artist's conceptions because it's it's reality. 267 00:27:56,700 --> 00:28:01,890 This isn't the only very cool thing that we've managed to learn about the formation of planets. 268 00:28:02,730 --> 00:28:07,650 So if you think about the planets in our own solar system, there is a very clear pattern to them. 269 00:28:07,920 --> 00:28:11,370 The rocky ones like Mars and Earth and Venus and Mercury. 270 00:28:11,670 --> 00:28:20,760 They all live close to the sun and the big gassy ones Jupiter, Saturn, Neptune and Uranus all live out at large distances from the sun. 271 00:28:21,690 --> 00:28:29,339 And a prevailing idea for why this is actually the case is that in the outer parts of 272 00:28:29,340 --> 00:28:33,930 one of these disks that are going to form generate the next generation of planets, 273 00:28:35,550 --> 00:28:37,380 that the conditions are colder. 274 00:28:37,830 --> 00:28:50,040 And so these molecules, these things like cyanide water, can condense out of the material, out of the planet forming disk and can give you a very big, 275 00:28:50,040 --> 00:28:57,419 solid core that is likely to serve as the seed for growing something big like Jupiter or Saturn in the inner parts of the solar system. 276 00:28:57,420 --> 00:29:05,010 The thinking is that if you can't have access to the ices that you get from freezing these molecules out of planet forming disk, 277 00:29:05,340 --> 00:29:08,940 then you are likely to not be able to form a core that is big enough, 278 00:29:08,940 --> 00:29:13,499 quick enough in order to capture a gas from the surrounding disk before the 279 00:29:13,500 --> 00:29:18,150 young sun becomes a jerk to the surrounding desk and just clears it all out. 280 00:29:19,170 --> 00:29:22,530 So there's a there's a big thinking that where you can form ice, 281 00:29:22,860 --> 00:29:30,480 where there has been a big idea that where you can form ice in a planet forming disk is a driver of the planets that could come out of it at the end. 282 00:29:31,680 --> 00:29:36,480 And excitingly, again, this is an idea and it's an old idea, 283 00:29:36,810 --> 00:29:41,310 but Alma has given us Alma has moved towards giving us the ability to take direct 284 00:29:41,310 --> 00:29:46,560 pictures of where ices form and don't form in the disks that form planets. 285 00:29:47,580 --> 00:29:50,159 So I'm showing you an example here. 286 00:29:50,160 --> 00:29:58,800 Again, it's an artist's conception of the icy outer part on the left and the not icy inner part on the on the inner part. 287 00:29:59,280 --> 00:30:04,440 Sorry. On the left, you see an artist's conception of the icy outer part and the not icy inner part. 288 00:30:04,740 --> 00:30:12,540 On the right, you see an actual picture, which again is stunning if you are looking to actually see this effect in nature. 289 00:30:12,540 --> 00:30:16,120 And so what you see, this is the disk that's forming planets. 290 00:30:16,140 --> 00:30:20,190 There's a young star named Hydra at the exact middle of this image. 291 00:30:22,230 --> 00:30:29,730 And what you see on the left is an illustration of the overall disk, of the overall structure of the disc. 292 00:30:30,120 --> 00:30:33,950 In the middle, what you see is the distribution of carbon monoxide. 293 00:30:34,350 --> 00:30:40,230 And then on the far right, you see the distribution of a chemical that only appears after a carbon monoxide has disappeared. 294 00:30:40,860 --> 00:30:48,870 And so this tells you that all of the carbon monoxide that you see in here has vanished onto the solids that we think 295 00:30:48,870 --> 00:30:55,050 might be seeding the formation of the next generation of Jupiter's over Saturn's in this disk around this young star. 296 00:30:55,560 --> 00:30:59,910 So carbon monoxide freezes out at a pretty low temperature of 20 Kelvin. 297 00:31:00,270 --> 00:31:05,250 So you see this transition very far out from the parent star with a great deal of effort. 298 00:31:05,910 --> 00:31:11,430 This has also been seen, but the picture is a little less pretty for water in one nearby star, 299 00:31:11,430 --> 00:31:14,940 although it's only captured when that star essentially emits a great big burp 300 00:31:14,940 --> 00:31:20,010 of light that temporarily pushes the location of water far out into the disk. 301 00:31:20,820 --> 00:31:28,110 But we can actually see the lines that we think are the chemical lines that we think are related to where you could form 302 00:31:28,920 --> 00:31:36,390 giant planets in these disks or where you're going to be stuck forming planets potentially like Earth in these disks. 303 00:31:37,860 --> 00:31:40,019 So I'll just say, you know, 304 00:31:40,020 --> 00:31:48,660 this is these examples of seeing our ideas about how planets formed turned into beautiful pictures of individual disks are extremely exciting, 305 00:31:49,440 --> 00:31:58,950 but the place that the field is going right now is to try to see many of these frost lines or snow lines in planet 306 00:31:58,950 --> 00:32:07,259 forming disks and to see the many of these telltale type gaps and structures in the disks that form planets. 307 00:32:07,260 --> 00:32:14,280 And the thing that's driving this is if people if you've read about the Kepler satellite or similar efforts, 308 00:32:14,610 --> 00:32:20,340 we now have a reasonable handle on the demographics of the planets that live around us in the Milky Way. 309 00:32:20,670 --> 00:32:27,299 And the big thing that Alma is working on trying to do by studying these disks around young stars is to try to put together 310 00:32:27,300 --> 00:32:34,260 a picture of how you actually form the distribution of planets that are seen by satellites like the Kepler satellite. 311 00:32:34,740 --> 00:32:42,510 So the direction that this field is going is in trying to give us a complete view of how planets form around young stars. 312 00:32:42,510 --> 00:32:48,180 Now that we've seen some of our idea that some of our first ideas validated or challenged by observations. 313 00:32:49,230 --> 00:32:55,470 So I will just say a couple of words about the other end of the universe, too, since the these pictures are much. 314 00:32:55,770 --> 00:32:59,190 Pretty than the pictures of planet forming disks. 315 00:32:59,460 --> 00:33:08,580 But that's because these are some of the most difficult, most most difficult and most important observations that Alma can make. 316 00:33:09,000 --> 00:33:14,550 And that's taking pictures of the formation of galaxies at the others on the other side of the observable universe. 317 00:33:15,330 --> 00:33:18,450 So this has also been a huge area for Alma's first few years. 318 00:33:19,200 --> 00:33:29,639 And the idea is that we can learn an enormous amount about how the first generations of stars were born in galaxies and how most of the galaxies 319 00:33:29,640 --> 00:33:38,560 that we see around us were actually built up by studying the gas and dust that are actually forming stars when the stars actually formed. 320 00:33:38,580 --> 00:33:44,880 And so we know that the first galaxies are born within a billion years after the Big Bang, 321 00:33:45,180 --> 00:33:50,340 and that most of the stars in the galaxies formed between six and 10 billion years ago. 322 00:33:50,610 --> 00:34:00,419 And so a huge amount of effort from Alma has gone into taking pictures of the galaxies that we think are right now, meaning 5 billion years ago, 323 00:34:00,420 --> 00:34:08,430 but catching the light from the galaxies as they actually build up most of their as they actually build up their stellar populations. 324 00:34:09,390 --> 00:34:15,430 And so maybe the most spectacular example of this here is here, which is taking this picture, 325 00:34:15,460 --> 00:34:19,290 Hubble's picture of nothing that I showed you at the beginning of the talk, 326 00:34:19,290 --> 00:34:23,999 showing us a universe full of galaxies that's in purple here and in orange. 327 00:34:24,000 --> 00:34:27,989 What you see is a picture with Alma of the same region showing you blazing 328 00:34:27,990 --> 00:34:34,020 reservoirs of gas that are actually forming new galaxies in the same region. 329 00:34:34,950 --> 00:34:41,219 And not just from these observations, but from a lot of observations that and I want what I want you to see here in that stream, 330 00:34:41,220 --> 00:34:43,620 the capabilities of both Hubble and Alma. 331 00:34:44,430 --> 00:34:53,190 We've managed to build up a picture where we understand that a lot of the build-up of galaxies, which occurred mostly again, 332 00:34:53,550 --> 00:35:00,360 10 billion plus or -1,000,000,000 years ago, occurred because these galaxies were richer in gas. 333 00:35:00,360 --> 00:35:07,799 And that gas is something that Alma can see. And so what you can see here qualitatively is that in the background, 334 00:35:07,800 --> 00:35:12,870 this picture with Hubble of stars from galaxies that are 10 billion light years away. 335 00:35:13,620 --> 00:35:23,550 And the similar picture in gas from Alma. So they both show us, you know, some details of the formation of stars in these objects, 336 00:35:23,820 --> 00:35:27,000 but they're both absolutely straining the capabilities of the telescope. 337 00:35:27,010 --> 00:35:31,650 If you think these just look like smudges and not beautiful pictures of galaxies, you're absolutely right. 338 00:35:32,070 --> 00:35:38,370 So these are things that are forming stars a thousand times more vigorously than the Milky Way galaxy, 339 00:35:38,370 --> 00:35:43,020 but they still just look like little smudges at the edge of our ability to take pictures with Alma. 340 00:35:44,070 --> 00:35:51,030 So I will again show you probably the flashiest example of using a trick provided to us by nature 341 00:35:52,260 --> 00:35:57,930 to break this and take a detailed picture of a galaxy as it's actually in the process of forming. 342 00:35:58,800 --> 00:36:05,310 And that takes advantage of a trick that is given to us essentially by general relativity. 343 00:36:05,310 --> 00:36:12,420 And thanks to Einstein, we know that mass curved space and that also curves the path that light follows and allows 344 00:36:12,510 --> 00:36:19,200 the gravity created by galaxies or clusters of galaxies to act as a additional lens, 345 00:36:19,440 --> 00:36:22,380 focusing light to us and making background objects brighter. 346 00:36:23,130 --> 00:36:33,060 So this lets you take your best telescope in the world that can only just barely see the formation of these galaxies and take advantage 347 00:36:33,060 --> 00:36:42,900 of an extra giant telescope that's been provided to you in space by the presence of a lucky super position of a foreground object, 348 00:36:43,230 --> 00:36:47,310 focusing the background light from these galaxies to you. 349 00:36:48,030 --> 00:36:53,820 And so there are examples of this that may be familiar to you if you've seen pictures of clusters of galaxies. 350 00:36:54,090 --> 00:37:01,410 This effect is seen in the optical, and you can see it in these sort of arcane features seen here and here. 351 00:37:01,770 --> 00:37:08,490 And what these are, is these are a dim background galaxy with its light heading off in directions that we would not catch. 352 00:37:09,060 --> 00:37:17,010 But that's caught on a curved path through space time and pointed back towards us by the presence of a large amount of mass in the foreground galaxy. 353 00:37:17,550 --> 00:37:19,560 And so you can see that illustrated a little bit here. 354 00:37:21,770 --> 00:37:30,350 But the really cool version of this and the most spectacular picture that all my has taken of a distant forming galaxy is here. 355 00:37:31,190 --> 00:37:39,950 And so the thing that you see on the left is a picture of a relatively low mass galaxy with the poetic name of ESDP 81. 356 00:37:41,030 --> 00:37:44,150 This thing looks like a ring, but it's not a ring. 357 00:37:44,420 --> 00:37:49,070 What this is, is it's an example of light that was heading off in many different directions. 358 00:37:49,430 --> 00:37:55,040 That's been caught by a galaxy between us and the background galaxy and bent back towards us. 359 00:37:55,580 --> 00:38:02,450 And so the result is that we see light coming in from these different directions where the path has been diverted as a ring. 360 00:38:02,750 --> 00:38:08,270 And the reason we don't see anything at the middle is because this galaxy that's bending the light is not full of gas and dust. 361 00:38:09,110 --> 00:38:15,770 On the right, you can see a picture of the distribution of stars and the ring of dust seen from the background galaxy. 362 00:38:16,160 --> 00:38:17,389 So you can use this, 363 00:38:17,390 --> 00:38:25,230 the fact that the galaxy is brightened because you're getting way more about it than you would expect to make a very precise picture of this galaxy. 364 00:38:25,250 --> 00:38:29,390 It takes a bunch of math and there is a mild amount of sketchy ness to this. 365 00:38:29,720 --> 00:38:35,930 But what you see is a galaxy that would be far too tiny for us to study that at the 366 00:38:35,930 --> 00:38:41,150 distance that it actually sits at sitting again many billions of light years away. 367 00:38:41,870 --> 00:38:50,630 And what you see is a bunch of stellar nurseries that are far more active and vigorous than anything like Orion that we see around us today. 368 00:38:50,990 --> 00:38:59,300 So tiny little things, tens of light years across, but that are collectively forming stars that are eight 100 times the Milky Way. 369 00:38:59,330 --> 00:39:05,059 And what you see again here is that the resolution with which you see these, 370 00:39:05,060 --> 00:39:08,630 the sharpness of the image that you can get thanks to the presence of the gravitational lens, 371 00:39:09,530 --> 00:39:14,299 is vastly higher than what you would get either from Alma alone or even trying to study the same object 372 00:39:14,300 --> 00:39:18,950 without the aid of the intervening gravitational lens from the space from the Hubble Space Telescope. 373 00:39:20,760 --> 00:39:26,280 So I want to spend one slide just pointing out that you have local people doing amazing things with 374 00:39:26,280 --> 00:39:34,139 Alma and this takes advantage not of the not of just being able to see the dust or see the molecules, 375 00:39:34,140 --> 00:39:38,640 but that ability to harness the Doppler effect that I mentioned, 376 00:39:38,970 --> 00:39:43,860 because you can tell very precisely how fast these molecules are moving towards or away from you. 377 00:39:44,700 --> 00:39:48,690 Alma is a very, very good machine for measuring how fast gas moves. 378 00:39:49,140 --> 00:39:54,660 And if you go look at the centres of galaxies, we know that most of the centres of galaxies, 379 00:39:54,660 --> 00:39:59,370 including our own milky Milky Way harbour giant supermassive black holes. 380 00:39:59,490 --> 00:40:03,540 So in our own Milky Way, this is a thing that's about 3 million times the mass of the sun. 381 00:40:04,320 --> 00:40:07,920 The biggest ones get up to billions of times the mass of the sun. 382 00:40:08,910 --> 00:40:17,120 But there are a huge number of mystery surrounding these black holes at the centres of galaxies, and a lot of that is because they're black holes. 383 00:40:17,130 --> 00:40:27,320 It's very hard to just point and say, oh, you know, in this part of this galaxy, there is a black hole with this much mass hanging out here. 384 00:40:27,330 --> 00:40:32,550 So unfortunately, you generally need something moving around it, which is the trick that's used here, 385 00:40:33,060 --> 00:40:37,320 or you need something to fall onto it in order to see the presence of a huge black hole. 386 00:40:37,740 --> 00:40:45,719 And so it turns out that Alma, by watching the disks of gas that tend to form in the inner parts of galaxies rotate under the gravitational 387 00:40:45,720 --> 00:40:50,790 influence of the black hole gives you one of the best ways to weigh black holes in the centres of galaxies. 388 00:40:51,240 --> 00:40:57,780 And so team led out of led out of Oxford has been using this to essentially deploy an 389 00:40:57,780 --> 00:41:03,000 entirely new way to measure the masses of black holes at the centres of galaxies. 390 00:41:04,540 --> 00:41:10,300 And if you want to watch, for one thing, in the next year, I think it's worth staying on black holes and it's worth mentioning. 391 00:41:10,450 --> 00:41:13,389 So this is something with Stephen Hawking passing away today. 392 00:41:13,390 --> 00:41:20,980 It's something it's very nice to mention that there is an amazing discovery regarding black holes potentially coming just down the pipe from Alma. 393 00:41:22,030 --> 00:41:24,310 So it's very neat to measure their masses. 394 00:41:24,610 --> 00:41:34,870 But Alma is actually the linchpin in the opportunity to take the first direct picture of a black hole and the way that that is thought to be possible. 395 00:41:35,330 --> 00:41:39,700 And we're hoping that it's possible is to use this broken mirror trick, 396 00:41:39,700 --> 00:41:48,250 the ability to use telescopes in concert as a telescope that is effectively much bigger, that is acting like the size of the array that you're using. 397 00:41:48,610 --> 00:41:58,180 But to take this up from just using a part of, you know, of the desert in the Andes to now using the whole Earth as your effective telescope. 398 00:41:58,660 --> 00:42:09,100 And so the idea is that by combining observations from Alma, with observations from Mexico and Hawaii and the South Pole and Spain, 399 00:42:09,820 --> 00:42:16,720 you can build a telescope that can take pictures with a precision as though it had the size of the entire earth. 400 00:42:17,110 --> 00:42:23,830 And that turns out to be almost exactly the right size of a telescope in order to see the black hole at the centre of our galaxy. 401 00:42:24,820 --> 00:42:28,690 So this is not a picture that Alma has taken that we know of. 402 00:42:29,950 --> 00:42:37,089 So but this is a simulation of what the black hole at the centre of our galaxy, which is 3 million solar masses, 403 00:42:37,090 --> 00:42:44,920 might look like as a cloud of gas falls onto it and that gas heats up and the light from that gas is bent as it comes towards us. 404 00:42:45,250 --> 00:42:51,489 And the result is that you see a you essentially see a shadow that amounts to the 405 00:42:51,490 --> 00:42:55,780 location of the event horizon of the black hole at the centre of the Milky Way. 406 00:42:56,950 --> 00:43:00,430 So people have speculated about the ability to see this for years. 407 00:43:00,820 --> 00:43:06,640 The observations have been taken. So the teams have these observations, and if they actually come through with this, 408 00:43:06,940 --> 00:43:12,940 this would be the first direct picture of the event horizon of a black hole, which would be really incredible. 409 00:43:13,960 --> 00:43:16,120 So far, they are not telling us what they've seen. 410 00:43:16,690 --> 00:43:25,599 But you should absolutely keep your eyes peeled for a headline coming perhaps any day or any month or you know, 411 00:43:25,600 --> 00:43:30,250 given the way things actually work, what is much more likely is that they will say they need a little bit more time. 412 00:43:31,660 --> 00:43:36,640 But some year here, we should get we should have the prospect of actually seeing this picture. 413 00:43:38,380 --> 00:43:41,260 So let me end by showing you a few slides, 414 00:43:41,260 --> 00:43:52,390 showing you what the way that my collaborators and I have been using the telescope and the stuff that we have been here discussing all week. 415 00:43:53,350 --> 00:43:59,559 And that's perhaps a little bit mundane than taking a direct picture of a black hole, but still very fundamental. 416 00:43:59,560 --> 00:44:07,420 And so what we're trying to do is to study how the nurseries that form stars depend, 417 00:44:07,720 --> 00:44:14,290 how the nurseries that form stars form live, die, and how they vary from place to place across the universe. 418 00:44:14,740 --> 00:44:21,820 And so I flashed pictures of the Taurus Stellar Nursery in the Orion Stellar Nursery a couple of times. 419 00:44:22,120 --> 00:44:24,670 But let me actually say a couple of words about what these things are. 420 00:44:25,000 --> 00:44:35,350 So we think that essentially every star and every planet formed in a cloud of dense, dark, cold gas, 421 00:44:35,380 --> 00:44:42,880 these things tend to be held together by their own gravity, and they tend to be a few tens to 100 light years across. 422 00:44:43,630 --> 00:44:49,840 These stellar nurseries sort of represent the densest clumps of material sitting inside the gas between stars. 423 00:44:50,560 --> 00:44:56,770 And Alma is very, very good at picking them out. And so you see pictures here of two of the ones that are nearest us. 424 00:44:57,850 --> 00:45:02,980 But what we haven't really been able to do up until we turned on this telescope in Chile 425 00:45:03,700 --> 00:45:12,040 is to go across the entire set of galaxies that we see around us in the universe and say, 426 00:45:12,040 --> 00:45:25,180 not only, you know, how do stellar nurseries look, not only looking a paltry 150 light years away or a paltry 80,000 light years away to Orion 1500. 427 00:45:26,530 --> 00:45:31,659 But how did how do Stellar Nurseries look as you go to other galaxies? 428 00:45:31,660 --> 00:45:35,290 How to stellar nurseries look in the inner parts of galaxies, the outer parts of galaxies? 429 00:45:35,290 --> 00:45:39,670 And how have they changed across time? How do they live? How do they die and how are they formed? 430 00:45:40,810 --> 00:45:50,200 And essentially the way that we are doing this is to take pictures of the gas across the entire face 431 00:45:50,200 --> 00:45:55,600 of all of the galaxies within 60 million light years that are actively forming stars right now. 432 00:45:55,660 --> 00:46:00,010 Reasonably big that Alma can see. And to see why this is a big jump. 433 00:46:01,180 --> 00:46:09,620 Let me show you the picture of the last time that. A group of astronomers tried to do this something like 15, 20 years ago. 434 00:46:09,920 --> 00:46:15,620 So this is the last time that we used a big array of telescopes to try to take pictures 435 00:46:15,620 --> 00:46:20,180 of essentially all of the galaxies that you could see within some limited distance. 436 00:46:20,810 --> 00:46:29,030 And what you're seeing here in red are pictures of the gas that we think is in individual stellar nurseries in these galaxies. 437 00:46:30,050 --> 00:46:34,070 And this is now pictures of the same two galaxies, but taken using Alma. 438 00:46:34,370 --> 00:46:40,849 So each of the dots here corresponds to one of those places like Taurus or Orion that's 439 00:46:40,850 --> 00:46:45,950 likely to give birth to a new generation of stars and make these galaxies bigger. 440 00:46:46,730 --> 00:46:56,230 And the jump here is astounding. So we're able to go from really struggling and really doing very hard work to, you know, 441 00:46:56,270 --> 00:47:07,940 take a relatively course picture to fairly easily taking a picture of all of the stellar nurseries across each of these galaxies. 442 00:47:07,950 --> 00:47:12,919 And the result is that what we expect to be able to do is to put together a picture of 443 00:47:12,920 --> 00:47:18,590 something like 100,000 of these stellar nurseries across all of the nearest hundred galaxies. 444 00:47:19,370 --> 00:47:28,190 And for those who have a penchant for for those who have a penchant for sort of older astronomical books. 445 00:47:28,610 --> 00:47:35,540 A little bit what we're trying to do, if you're familiar with these sort of beautiful pictures of galaxies from the Hubble Atlas, 446 00:47:35,540 --> 00:47:39,020 of galaxies put together by our standards in about the middle part of the century, 447 00:47:39,410 --> 00:47:44,870 is we're trying to build the first sort of book of galaxies that you can see as looked 448 00:47:44,870 --> 00:47:49,910 at in the millimetre that have the same quality of images as you see in optical light. 449 00:47:50,960 --> 00:47:55,340 And to really learn about where where stellar nurseries live in their galaxies. 450 00:47:56,960 --> 00:48:00,590 So I mentioned I want to show you one movie and then a couple more. Pretty pictures on this, too. 451 00:48:00,600 --> 00:48:08,330 Just too close. I mentioned that when we take pictures of this gas, we also capture its motions. 452 00:48:09,260 --> 00:48:12,710 And so that's exactly what we see here. I will. 453 00:48:13,640 --> 00:48:17,299 So what I'm showing you here is a picture of a galaxy on the left and then on the right. 454 00:48:17,300 --> 00:48:25,280 What you're watching is a fly through of the galaxy where each individual frame shows a different speed of gas coming towards or away from you. 455 00:48:25,610 --> 00:48:32,780 So as we take pictures of these galaxies, we also get we also capture how fast the gas is moving towards or away from us. 456 00:48:33,170 --> 00:48:38,450 And if this looks confusing, then I think this is probably a nicer way to see it. 457 00:48:38,750 --> 00:48:42,920 So as we take pictures of these galaxies, we not only see where the stellar nurseries are, 458 00:48:43,280 --> 00:48:49,800 but we watch how the stellar nurseries are moving and how the gas moves inside the individual stellar rings. 459 00:48:50,180 --> 00:48:57,920 And so what you see here are images of how fast the gas moves across the face of both of these galaxies that I've been showing you. 460 00:48:58,280 --> 00:49:04,290 And the main motion that you see here is just that this gas moves away from you and this gas moves towards you. 461 00:49:04,310 --> 00:49:10,850 So what you're looking at are tilted, spinning Frisbees with the rotation of the gas here, 462 00:49:10,850 --> 00:49:14,240 driven by the gravity of the stars and the dark matter in the galaxy. 463 00:49:14,630 --> 00:49:20,240 But there's a lot more subtle motions here related to the arms at bars that relate to how you're pulling 464 00:49:20,240 --> 00:49:25,250 the gas together and forming these stellar nurseries and then tearing them apart that are fascinating. 465 00:49:27,100 --> 00:49:31,990 And I will close by just saying a couple of words on what we found so far. 466 00:49:32,260 --> 00:49:36,220 But this is really you know, this project right now is delivering. 467 00:49:36,790 --> 00:49:42,639 It's taking its observations and sending the data using up a big chunk of the Internet 468 00:49:42,640 --> 00:49:49,660 pipeline between Chile and North America and then piping stuff to us sort of day by day. 469 00:49:49,690 --> 00:49:54,940 So this is really a project that is happening right now at at all. 470 00:49:55,570 --> 00:50:01,299 But we already have the first few images that I'm showing you. And what we see are some really spectacular pictures. 471 00:50:01,300 --> 00:50:08,320 And I really like this picture which combines Alma in purple with a picture of where we know that. 472 00:50:08,320 --> 00:50:15,670 So I'm calling these things stellar nurseries. The picture in yellow is showing you where we know that young stars have recently formed. 473 00:50:16,000 --> 00:50:24,340 And what you see stunningly from this picture is that the it's very clear that the stellar nurseries and the young stars live close to each other. 474 00:50:24,790 --> 00:50:33,910 But it's also the case that the stars that have just formed are not living exactly where you see the star, the stellar nurseries from Alma. 475 00:50:34,420 --> 00:50:39,880 And our understanding of this is that stars are essentially huge jerks to their parents. 476 00:50:41,380 --> 00:50:45,850 So when you form these young stars, these young stars start pouring out light. 477 00:50:46,270 --> 00:50:54,730 When the same winds that clear out protoplanetary disks or the planet forming disks come off of these stars and start hitting the parent cloud. 478 00:50:55,720 --> 00:51:01,870 And then in fairly short order, the biggest of these young stars collapses and explodes as a supernova. 479 00:51:02,320 --> 00:51:10,780 And so what we think is that you're seeing the offset between these stellar nurseries that will form stars in the near future and the places 480 00:51:10,780 --> 00:51:19,990 where young stars have already formed because those young stars have annihilated the clouds that they that actually gave birth to them. 481 00:51:20,830 --> 00:51:24,870 So you see them closely associated, but not directly on top of each other. 482 00:51:26,660 --> 00:51:30,170 And then I would just say by way of sort of, you know, 483 00:51:30,380 --> 00:51:38,930 the other things that we're finding as opposed to showing you a sort of bunch of very technical graphs, I would say qualitatively, 484 00:51:39,560 --> 00:51:44,570 the very neat things that we're finding are that the stellar nurseries do really very dramatically 485 00:51:44,570 --> 00:51:49,130 from place to place as we look across all of the different galaxies in the nearby universe. 486 00:51:50,090 --> 00:51:53,030 And so what we see strikingly is that you get big star, 487 00:51:53,390 --> 00:52:02,600 you get big stellar nurseries with violent motions in the inner parts of galaxies and on the spiral arms that we see. 488 00:52:03,500 --> 00:52:11,120 And in dinky little galaxies, we see them forming tiny, stellar nurseries with comparatively less violent motions. 489 00:52:12,170 --> 00:52:21,139 But overall, the sense that we are getting from these first few, from the first few observations that we've managed to take on this program, 490 00:52:21,140 --> 00:52:28,370 are that it's really it seems very clear that the nurseries that form stars do know about the galaxies that they live in. 491 00:52:29,360 --> 00:52:35,620 It is less clear whether the stars that come out the other end and the planets that come out the other end are deeply affected by this. 492 00:52:35,630 --> 00:52:42,620 But this is something that we hope to have a good answer to within, you know, maybe months, but years, the next few years. 493 00:52:43,880 --> 00:52:53,540 So I would end there and say, I hope that I have at least convinced you that there is a quiet or maybe not quiet revolution 494 00:52:53,540 --> 00:53:00,570 going on in astronomy and specifically this field of long wavelength astronomy or. 495 00:53:01,220 --> 00:53:06,680 Mm. Astronomy is being absolutely revolutionised by hauling 70 of the best telescopes 496 00:53:06,680 --> 00:53:10,700 that we can make up to the most or most remote place that we could take them, 497 00:53:11,000 --> 00:53:18,350 and then pointing them at the structures that form planets and pointing them at galaxies as they're being born across the other side of the universe. 498 00:53:19,520 --> 00:53:27,650 And then using the motions that this thing can see to away black holes ends up at way galaxies. 499 00:53:28,520 --> 00:53:32,479 And then hopefully if you stay tuned, we're also taking the first picture that we've ever had, 500 00:53:32,480 --> 00:53:36,710 of the first direct picture that we've ever had of a black hole. 501 00:53:37,940 --> 00:53:44,030 And still, you should stay tuned and keep an eye out also for what we're learning about how 502 00:53:44,870 --> 00:53:50,300 the nurseries that give birth to stars change across the across the universe. 503 00:53:50,750 --> 00:53:51,050 Thanks.