1 00:00:11,700 --> 00:00:16,830 Good afternoon, ladies and gentlemen. Welcome to the 103rd Hall Lecture. 2 00:00:18,820 --> 00:00:26,140 I'm delighted to be able to introduce to you today Professor Naveen Van de SEC from Leiden. 3 00:00:26,170 --> 00:00:32,890 She is an astronomer and a chemist. And that's an unusual and very special set of skills. 4 00:00:33,700 --> 00:00:42,340 She's a professor of molecular astrophysics at Leiden Observatory in the Netherlands and director of the Sackler Laboratory for Astrophysics. 5 00:00:42,940 --> 00:00:47,200 She's also a member of the Max Planck Institute for Terrestrial Astrophysics in Garching. 6 00:00:48,640 --> 00:00:52,030 She had her Ph.D. in Leiden before the United States for a while, 7 00:00:52,030 --> 00:01:00,700 where she worked at Harvard Institute of Advanced Study in Princeton and Caltech before she returned to Leiden and became a professor there in 1995. 8 00:01:01,900 --> 00:01:05,560 She works on interstellar molecules, star formation, planet formation, 9 00:01:05,860 --> 00:01:12,970 submillimeter and millimetre astronomy and the basic radiative transfer processes that go along with working in that field. 10 00:01:13,690 --> 00:01:16,810 She is an extraordinarily eminent astronomer. 11 00:01:17,200 --> 00:01:23,410 She's a member of the Dutch Royal Dutch Academy of Sciences and the U.S. National Academy of Sciences. 12 00:01:23,860 --> 00:01:30,160 She's played a crucial role in the development of many of the forefront facilities that astronomers use today, 13 00:01:30,580 --> 00:01:36,850 most topically and recently the alma interferometer in Chile, the Herschel satellite. 14 00:01:37,330 --> 00:01:40,450 And to be looked forward to the James Webb Space Telescope. 15 00:01:40,810 --> 00:01:50,320 She was responsible for one of the instruments. She has published an astonishing 370 papers that have been cited over 20,000 times. 16 00:01:51,130 --> 00:01:56,950 She's had 34 Ph.D. students. This is a remarkable person who's going to speak to us today. 17 00:01:57,820 --> 00:02:05,560 There's a list of accolades which goes now down from halfway on this page to the entire other side of the page and beyond. 18 00:02:05,770 --> 00:02:13,090 But I'm not going to read all those. I'll just pick a few. She's the gold medal holder of the Royal Dutch Chemical Society. 19 00:02:13,990 --> 00:02:18,010 In 2000, she won the highest scientific wall award in the Netherlands, 20 00:02:18,010 --> 00:02:24,610 the Spinoza Prize 2001, the Burke Award of the Royal Society of Chemistry here in the U.K. 21 00:02:25,510 --> 00:02:32,200 She's a foreign member of the American Academy of Arts and Sciences, an honorary fellow of the Royal Astronomical Society, 22 00:02:32,680 --> 00:02:37,450 and just last year became an Academy professor of the Royal Dutch Academy of Sciences. 23 00:02:38,050 --> 00:02:44,440 So it's my great pleasure to introduce Professor Irene Van de Sic to deliver the 103rd Halley Lecture. 24 00:02:44,620 --> 00:02:47,980 Building stars, planets and the ingredients for life between the stars. 25 00:02:48,430 --> 00:03:00,120 If you. Okay. 26 00:03:00,130 --> 00:03:03,360 Well, thank you very much, Roger, for this very kind introduction. 27 00:03:03,370 --> 00:03:11,620 And I want to thank you and the entire department actually here at Oxford for inviting me to give this very prestigious lecture. 28 00:03:11,890 --> 00:03:18,640 And so I'm really delighted to be here. Although it could be a little bit dry or on the other hand, my story is partly about water. 29 00:03:18,640 --> 00:03:22,270 So maybe that's sort of good, a good omen. 30 00:03:22,750 --> 00:03:29,559 And so what I'm going to do today is actually take you on a tour of the matter between to the stars, 31 00:03:29,560 --> 00:03:35,920 the interstellar space, and see how how out of this very tenuous material that you see over here. 32 00:03:36,280 --> 00:03:43,570 You actually built the stars and the planets and clouds like our own first that we that we live on. 33 00:03:45,100 --> 00:03:52,350 So this is a very broad subject, and I'm going to tell it at a very general level as well, 34 00:03:52,390 --> 00:03:56,320 because there may also be people from there, the general public here. 35 00:03:56,680 --> 00:04:02,259 And but I'll interspersed with some more detailed recent results to give you a 36 00:04:02,260 --> 00:04:06,520 flavour of everything that is happening actually at the moment in this field. 37 00:04:07,760 --> 00:04:10,249 But before we do so, since this is the only lecture, 38 00:04:10,250 --> 00:04:19,159 I want to make a tribute to Edmund Talley and all the work that he has done and is actually very relevant to the story that I'm going to tell, 39 00:04:19,160 --> 00:04:24,370 because in the ends of my lecture, I'll get actually two comments and they're ingredients. 40 00:04:24,380 --> 00:04:32,030 And so what you see here is, is basically one of the aspirations of Halley's Comet in 1986. 41 00:04:32,030 --> 00:04:40,880 And of course, then we could take a first peek at the nucleus of a comet and actually see what it is made of and what it looks like. 42 00:04:41,300 --> 00:04:49,730 And so the very end I'll come back to actually how these these nuclei of comets, these planetesimals are actually built. 43 00:04:52,200 --> 00:04:59,770 But it's not just astronomers, that's physicists and scientists that are interested in this story of our origins. 44 00:04:59,790 --> 00:05:04,440 It's you see it also throughout our culture in many different ways. 45 00:05:04,800 --> 00:05:08,879 And one of my hobbies is actually astronomy and art. 46 00:05:08,880 --> 00:05:21,000 And so I like to to find sort of pictures that have special paintings that sort of depict and also part of the story. 47 00:05:21,390 --> 00:05:25,590 So, of course, in the Netherlands here there's several faces, Starry Night. 48 00:05:25,590 --> 00:05:28,500 So you just have to paint this this picture. 49 00:05:28,830 --> 00:05:36,670 If you go to German expressionists, Kandinsky already painted here the stars and even long before molecular clouds were known. 50 00:05:36,930 --> 00:05:45,629 He already has these stars forming somewhere inside the dense clouds, and it's being heated and irradiated by some nearby star, 51 00:05:45,630 --> 00:05:52,350 as you can see, as it's sort of a like if you go to another part of the world, here is Day Australia, 52 00:05:52,350 --> 00:06:01,320 Aboriginal Art and with the seven sisters here sitting in the centre of the Milky Way, hidden there by their mother, 53 00:06:01,860 --> 00:06:08,340 who keeps them away from Orion, which is the old man that is chasing actually these seven sisters. 54 00:06:09,150 --> 00:06:14,160 And finally, you know, the Pacific Northwest and northern Canada. 55 00:06:14,490 --> 00:06:24,300 And there is the story of a first raven actually stealing the sun out of a dark box where the moon to put it and then putting the sun up at the sky. 56 00:06:24,450 --> 00:06:35,730 So these are all stories about stars, about the origins of stars, the origins of of planets that you see reflected actually throughout culture. 57 00:06:36,420 --> 00:06:42,070 And in fact, of course, Halley's Comet has been an inspiration to many artists as well. 58 00:06:42,390 --> 00:06:47,459 And the famous tapestry on bear here, where you see the Halley's Comet, 59 00:06:47,460 --> 00:06:52,620 said a 1066 appearance, which was particularly bright and which you see up here. 60 00:06:53,460 --> 00:06:59,940 And that also got a very famous painting in one of the chapels in Florence. 61 00:07:00,300 --> 00:07:04,650 And where you see here, this is not the end of the negativity. 62 00:07:04,650 --> 00:07:12,330 This is not the star of Bethlehem. This is actually a comet. And again, inspired by the 31 appearance of Italy. 63 00:07:13,440 --> 00:07:18,599 But even the Native Americans reflect it and see it as actually in the petroglyphs. 64 00:07:18,600 --> 00:07:22,530 Here again, to the 1066 appearance, which was so, so prominent. 65 00:07:24,610 --> 00:07:31,989 And so basically the origin of of comets and the origins of solar systems is, of course, 66 00:07:31,990 --> 00:07:38,470 a topic that has now become very much in the forefront again with the discovery of exoplanets, 67 00:07:38,500 --> 00:07:42,250 planets that circle around stars other than our own sun. 68 00:07:43,000 --> 00:07:49,149 And it's only less than 20 years ago that the first exoplanets were discovered by now. 69 00:07:49,150 --> 00:07:54,040 It's a field that is really booming. It's one of the fastest growing fields in astronomy. 70 00:07:54,550 --> 00:07:58,870 And right now, close to a thousand exoplanets have been discovered. 71 00:07:59,530 --> 00:08:04,450 And that makes all of these questions as to how these planets were actually formed, 72 00:08:04,810 --> 00:08:08,680 whether these outer planetary systems are similar to our own or not. 73 00:08:09,490 --> 00:08:17,500 How unique is our own solar system also in its architecture, and which of these planets could actually be habitable? 74 00:08:18,280 --> 00:08:22,960 And so that is sort of the context of the story that I would going to tell you here today. 75 00:08:24,340 --> 00:08:30,860 So let's orient ourselves as to where we are going to look for America to look very much in the solar neighbourhood, close, 76 00:08:31,410 --> 00:08:39,310 close to home, so to say, because that's where we have the highest spatial resolution, that's where we can see the sharpest. 77 00:08:40,540 --> 00:08:43,930 But all of the processes I'm going to tell you about actually happens throughout 78 00:08:44,450 --> 00:08:50,950 our entire Milky Way and even in other galaxies out to the edge of the universe. 79 00:08:51,190 --> 00:08:59,860 In fact, molecules like water and carbon monoxide have now been seen out to distances corresponding 80 00:08:59,860 --> 00:09:05,290 to when the lifetime of the universe was only sort of 10% of its current age. 81 00:09:05,740 --> 00:09:14,680 So really very, very large distances. So so this is basically to remind you where we are actually where here, 82 00:09:14,930 --> 00:09:22,420 if you would look on top of our own Milky Way and our Star of the Sun is only one of some hundred, 83 00:09:22,540 --> 00:09:30,400 several hundred billion stars here in this Milky Way, and then sort of halfway out to the edge of the Milky Way. 84 00:09:32,840 --> 00:09:39,830 So why are these stars and planets formed? Well, they are formed in the very tenuous material that is between the stars. 85 00:09:40,040 --> 00:09:48,370 It was only sort of around 1900s that astronomers realised that the regions between the stars were not empty. 86 00:09:48,380 --> 00:09:56,060 But the field is a very, very dilute gas and it's the more denser concentrations of this gas where the stars are being born. 87 00:09:57,010 --> 00:10:06,460 So here's a good example of one nebula where we actually have a lot of stars being formed at this moment here in the famous constellation Orion. 88 00:10:06,730 --> 00:10:15,130 And here we have done the Orion Nebula. And if you look at it with a more modern telescope, then you see that it's not just a few stars, 89 00:10:15,160 --> 00:10:18,910 a few bright stars that were seen already by 300 years ago. 90 00:10:19,660 --> 00:10:26,020 But you see here, actually, a nursery of some hundreds young several hundred young stars. 91 00:10:26,590 --> 00:10:31,149 Now, William Herschel, he actually speculated already that something like the Orion Nebula, 92 00:10:31,150 --> 00:10:39,130 which he was able to see this little telescope in his backyard, that these were the chaotic material of future suns. 93 00:10:39,610 --> 00:10:48,520 But at that time, when Herschel said this, it was not even realised recognised that stars actually don't have very internal life. 94 00:10:48,760 --> 00:10:52,180 Stars actually are born and they also die again. 95 00:10:52,570 --> 00:10:56,800 And and and that's that is an integral part of the whole story. 96 00:10:57,700 --> 00:11:05,500 So the Orion Nebula is actually one of the prime nurseries of new stars in in our galaxy. 97 00:11:06,220 --> 00:11:11,470 Here you see another image in this case taken by the Hubble Space Telescope, now on a somewhat larger scale. 98 00:11:11,810 --> 00:11:21,250 And you see also these dark regions here. You see them also in other places, these these bright nebulae, a sort of dusty, 99 00:11:21,250 --> 00:11:28,300 ionised gas that is emitting brightly in the the optical wavelengths regime. 100 00:11:29,020 --> 00:11:35,920 But you see also here, these these very dark clouds. And these clouds are dark because they can contain very tiny dust particles, 101 00:11:36,370 --> 00:11:41,920 small silicate material, small carbonaceous material, which absorbs and scatters starlight. 102 00:11:42,490 --> 00:11:46,030 And that is why these clouds look so look so dark. 103 00:11:47,270 --> 00:11:52,210 And we can see them them as a silhouette, basically against this bright background. 104 00:11:53,750 --> 00:11:58,430 Now these clouds are large. They can be several light years across. 105 00:11:59,090 --> 00:12:06,890 They can also be very massive. Some of these clouds or the larger cloud complexes can have masses up to a hundred thousand solar masses, 106 00:12:07,370 --> 00:12:13,040 meaning that they have enough material in order to 400,000 new suns. 107 00:12:13,580 --> 00:12:17,060 They won't do that. They actually have a lot of low efficiency of forming new stars. 108 00:12:17,270 --> 00:12:21,860 But in plants, in principle, there's lots of material presence to do so. 109 00:12:26,280 --> 00:12:30,630 So let's look in a little bit more detail at some of these dark clouds. 110 00:12:31,080 --> 00:12:37,230 So here you see a nice example. I show that there's a small dark cloud also called a coal sack. 111 00:12:37,240 --> 00:12:45,600 This one actually on the southern sky. And you see it again hanging here in front of the thousands of stars here in the Milky Way. 112 00:12:47,690 --> 00:12:58,530 And so these clouds contain about 99% gas, mostly hydrogen, and about 1% by mass of this solid material. 113 00:12:58,980 --> 00:13:04,530 And as I mentioned already, this sort of material is typically silica silicates. 114 00:13:04,850 --> 00:13:10,770 And I've seen gas, little sounds, grains and also carbonaceous material. 115 00:13:10,920 --> 00:13:18,570 And it's typically only a 10th of a micrometre in size and thousands of a ten thousands of a millimetre. 116 00:13:19,350 --> 00:13:26,159 So very small dust particles. And but they are responsible for making these clouds look dark. 117 00:13:26,160 --> 00:13:26,910 And thus we will see. 118 00:13:26,910 --> 00:13:35,310 They actually also play a role in shielding the molecules from the dissociated radiation of the stars and therefore making them survive. 119 00:13:36,260 --> 00:13:39,920 These clouds are cold, stay only slightly above the absolute zero, 120 00:13:40,670 --> 00:13:45,470 and they have densities of typically about a thousand particles per cubic centimetre. 121 00:13:46,340 --> 00:13:53,240 Now this one cubic centimetre here in this room contains probably of the order of ten to the 19 particles per cubic centimetres. 122 00:13:53,570 --> 00:14:01,790 And even a good vacuum in a laboratory on Earth still, still has something of the order of, say, 100 million particles per cubic centimetre. 123 00:14:02,330 --> 00:14:10,100 So what an astronomer calls a dense cloud is still a much better vacuum than we normally have in the laboratory on Earth. 124 00:14:10,370 --> 00:14:16,310 And that is really what makes these clouds also so interesting for chemists, because they are actually quite unique. 125 00:14:16,940 --> 00:14:22,800 Chemical physics laboratory. So how do we observe these clouds? 126 00:14:23,250 --> 00:14:29,069 Well, it's nice to see these dark regions here in optical image, and that certainly recognises that. 127 00:14:29,070 --> 00:14:36,990 You recognise that there is a cloud there. And but if you want to see actually what's inside the clouds, then we need to go to longer wavelengths. 128 00:14:36,990 --> 00:14:45,809 You basically need to put on the glasses, we need to put on infrared glasses or even longer in order to go to the longer 129 00:14:45,810 --> 00:14:50,700 wavelengths where the scattering and absorption of the light is much less. 130 00:14:51,180 --> 00:14:56,010 And so you see here an image of the same cloud, but now in infrared wavelengths. 131 00:14:56,400 --> 00:15:00,930 And you see that you can actually see through the clouds and see the background stars. 132 00:15:01,170 --> 00:15:05,310 But you can also now actually studied material that is present inside of clouds. 133 00:15:06,450 --> 00:15:16,890 So this is actually a nice movie that was made by the Spitzer Space Telescope, a satellite which flew between 2003 and 2009. 134 00:15:17,970 --> 00:15:21,240 And what we are doing here is we're taking here one of these dark clouds. 135 00:15:21,630 --> 00:15:25,770 And so these are actual thermal images, actually, from one of our programs. 136 00:15:26,880 --> 00:15:31,560 And it's we go as we are zooming in, we're also going to do longer and longer wavelengths. 137 00:15:32,100 --> 00:15:36,299 And so we're zooming in. And what we see is that the dark regions disappear. 138 00:15:36,300 --> 00:15:41,850 And actually inside this dark cloud there is a young started is at this moment being formed. 139 00:15:42,810 --> 00:15:48,180 And these young star is still trying to push away the surrounding material through the so-called 140 00:15:48,180 --> 00:15:55,650 jets and winds and jets that it has here in these two directions in a bipolar direction. 141 00:15:56,670 --> 00:16:03,720 So the colour coded here in this image is such that says here is obviously to start and that's 142 00:16:03,960 --> 00:16:10,230 the green is a filter that actually contains the hottest molecular gas and the rarest. 143 00:16:10,230 --> 00:16:19,770 A red filter that you see here is actually a filter that contains emission from very large molecules d so called polycyclic aromatic hydrocarbons. 144 00:16:20,160 --> 00:16:27,360 And so these are actually molecules that are being excited by this radiation that emits them in the infrared wavelengths range. 145 00:16:27,360 --> 00:16:32,340 And that's see that's what you see here, nicely reflected in this in this image. 146 00:16:35,230 --> 00:16:43,840 So astronomy is very much driven by the facilities, by the big telescopes that come that allow us to to observe at various wavelengths. 147 00:16:43,840 --> 00:16:50,410 And we have been very fortunate that in the last decades to have a number of very powerful telescopes that are very well suited, 148 00:16:50,680 --> 00:16:54,400 especially to to probe into these dark regions. 149 00:16:55,600 --> 00:16:58,419 So here are my examples of the space telescope. 150 00:16:58,420 --> 00:17:06,010 And I want to mention in particular the Herschel Space Observatory, which is actually the largest astronomical telescope in space. 151 00:17:07,120 --> 00:17:10,120 In fact, it's run out of coolant just a few weeks ago. 152 00:17:10,120 --> 00:17:15,370 So it was launched in 2009 and it was operative until just a few weeks ago. 153 00:17:16,030 --> 00:17:22,929 But at this very moment, we are still very busy and analysing all of the results from this from this telescope, 154 00:17:22,930 --> 00:17:30,220 especially for one of two instruments, two hi fi instruments that was actually built under the leadership of of the Netherlands. 155 00:17:31,450 --> 00:17:33,579 And of course, we want to go above the Earth's atmosphere, 156 00:17:33,580 --> 00:17:39,100 because the Earth's atmosphere actually blocks a lot of the radiation and prevents it from coming to Earth. 157 00:17:39,460 --> 00:17:47,650 And especially because our radiation, our atmosphere contains so much water and oxygen and also CO2, 158 00:17:47,920 --> 00:17:55,810 we really have to get above the Earth's atmosphere in order to observe these crucial ingredients and for chemistry. 159 00:17:57,680 --> 00:18:01,640 Just to give you an indication of the progress that we actually have made. 160 00:18:02,300 --> 00:18:03,410 So 30 years ago, 161 00:18:03,410 --> 00:18:12,860 this was sort of the best image that we could take in the far infrared wavelengths range C around 100 micrometers off such a star forming a cloud. 162 00:18:12,860 --> 00:18:16,970 It was really not much more than a sort of a single pixel on the sky. 163 00:18:17,450 --> 00:18:22,760 And so if you look basically at the kind of images that Herschel has been returning, 164 00:18:23,180 --> 00:18:29,000 and then it's really fantastic to see the detail now in all of these molecular clouds. 165 00:18:29,480 --> 00:18:37,490 Again, the colour coding is such here. That's really was actually two shorter wavelengths and red is the longer wavelengths. 166 00:18:37,490 --> 00:18:40,879 So here we're looking at the somewhat warmer parts of the sky. 167 00:18:40,880 --> 00:18:45,050 This cloud is irradiated by a bright star from this size. 168 00:18:45,290 --> 00:18:49,100 And here we're looking at the somewhat cooler part of the cloud. 169 00:18:49,640 --> 00:18:57,950 But all these little point sources that you see over here are actually new stars that are being formed at this very moment. 170 00:18:58,250 --> 00:19:04,880 And we see already filaments and ridges, etc., which is where most of these star formation takes place. 171 00:19:05,270 --> 00:19:10,099 But it's really beautiful to see how Herschel has sort of unveiled these these clouds. 172 00:19:10,100 --> 00:19:16,400 And as we can now look at them in the thermal emission, basically, that is so-called dust grains emits. 173 00:19:18,080 --> 00:19:24,920 If you go to a somewhat later stage, if you look at where planets are being formed, again, we have come a long way. 174 00:19:24,920 --> 00:19:36,020 This is a famous graph from the iris satellites, one of the first infrared satellites which saw an excess of emission over a stellar photosphere. 175 00:19:36,530 --> 00:19:40,880 And now as Herschel, actually we have been able to make an image. 176 00:19:41,720 --> 00:19:47,959 So what used to be just one flux at a pixel is now a beautiful image here of this as the source, 177 00:19:47,960 --> 00:19:59,700 where here we have two star and here we have a ring of cold dust where there's just this small dust grains actually produced by collisions of big, 178 00:19:59,960 --> 00:20:06,710 bigger blocks and that are actually the remnants of planet formation. 179 00:20:06,950 --> 00:20:11,840 And I will come back actually to this this kind of process at the end of my talk. 180 00:20:13,820 --> 00:20:23,090 And of course, the private savvy also have very powerful telescopes we can think of to the very large telescopes of the European Southern Observatory, 181 00:20:24,110 --> 00:20:30,620 which are the possibly the most powerful instruments that we have on Earth. 182 00:20:31,490 --> 00:20:36,320 And if you go to longer wavelengths than we have some of the pioneering millimetre telescopes. 183 00:20:36,740 --> 00:20:40,340 And I want to mention here, especially the James Clerk Maxwell telescope, 184 00:20:40,340 --> 00:20:48,530 which has been a and still is a collaboration of and does in the United Kingdom. 185 00:20:48,740 --> 00:20:53,870 So England and the Netherlands and Canada, although the Netherlands just ended its participation, 186 00:20:53,870 --> 00:21:03,680 but for many years we have been observing together actually here on this telescope and basically opening up the millimetre wavelength regime. 187 00:21:05,600 --> 00:21:14,990 And of course, the major new facility that has just been inaugurated only two months ago here in Chile is the Atacama Large millimetre array. 188 00:21:15,650 --> 00:21:19,940 Oh, wow. Here is a picture that's actually representative of the day. 189 00:21:20,510 --> 00:21:30,950 This is a big collaboration, actually, of the actually the first worldwide collaboration in astronomy, 190 00:21:31,010 --> 00:21:39,650 both Europe and North America and also East Asia, coming together to build 66 telescopes on this high site here in Chile. 191 00:21:40,520 --> 00:21:43,700 And I'm very pleased to see actually that's Richard Hills, 192 00:21:43,700 --> 00:21:50,479 who has played a very important role in making this telescope actually work, that he's actually here in the audience. 193 00:21:50,480 --> 00:21:58,670 And we owe a lot to him and all of his other staff of the observatory to provide us with some of the beautiful images that we are now getting here. 194 00:21:59,240 --> 00:22:05,510 And this is what it will look like in about a year time when all of the 66 telescopes are there. 195 00:22:05,840 --> 00:22:13,010 And I can assure you, it is really already a breathtaking experience to be there, both literally and figuratively. 196 00:22:13,280 --> 00:22:21,480 And they're up there at 5000 metres. And I always open up, up as scientific eyes. 197 00:22:21,570 --> 00:22:25,170 Just to give you an impression of what the facility looks like. 198 00:22:25,440 --> 00:22:33,749 So here is basically at the 3000 metre level is where the telescopes are being assembled and then they are put on a big truck 199 00:22:33,750 --> 00:22:43,950 and then driven up to the road here to the 5000 metres region where they're built and then used for scientific observations. 200 00:22:45,570 --> 00:22:50,700 Okay. So that is some of the broke ground down on the facilities that we're using. 201 00:22:50,700 --> 00:22:53,130 But the observations are only one part of the story. 202 00:22:53,610 --> 00:22:59,580 If you want to learn something about stars and planets and especially the ingredients that go in there, 203 00:22:59,940 --> 00:23:05,300 and then you have to also combine it with models and also what I call the laboratory, 204 00:23:05,310 --> 00:23:12,930 although that can also be a computer actually laboratory, which provides the critical ingredients for both the observations and the models. 205 00:23:13,500 --> 00:23:17,610 So let's talk a little bit about the ingredients that we actually have in these clouds. 206 00:23:18,660 --> 00:23:29,790 So this is actually the astronomers view of the periodic table, which emphasises that the universe is mostly of hydrogen and followed by helium. 207 00:23:29,790 --> 00:23:34,020 But helium is chemically not that interesting, and that's a chemically interesting. 208 00:23:34,050 --> 00:23:40,950 Elements like carbon, hydrogen and oxygen are really way down at the level of a few times 10 to -4. 209 00:23:40,950 --> 00:23:46,390 Ms. Respect to hydrogen. And so what we have is this very tenuous gas. 210 00:23:46,420 --> 00:23:49,989 Very cold, mostly hydrogen here and there. 211 00:23:49,990 --> 00:23:56,290 And interesting elements. These elements may not meet each other, you know, for 25 years or so. 212 00:23:57,010 --> 00:24:04,690 So chemists had always told astronomers, well, don't bother to even go out and look for molecules because you simply won't see them. 213 00:24:05,830 --> 00:24:13,900 Well, fortunately, the astronomers didn't listen and they turned to the receivers and actually found a whole wealth of different molecules there. 214 00:24:14,440 --> 00:24:20,300 So this is just an example of the richness of features in the Orion Nebula. 215 00:24:20,320 --> 00:24:27,370 So now we are taking Herschel and pointing to Hi-Fi Instruments, a natural light instrument on the Orion Nebula. 216 00:24:27,370 --> 00:24:29,560 And this is an almost complete spectral scan. 217 00:24:30,100 --> 00:24:35,319 And it's you see already there are lots of lines there, but it's just to warn you that this is not noise. 218 00:24:35,320 --> 00:24:43,240 But if you start to blow this up, then we actually see that this little part is actually there are all all real 219 00:24:43,240 --> 00:24:47,530 lines and there's no no noise whatsoever that you can see in the spectrum. 220 00:24:47,530 --> 00:24:53,560 You see already here patterns of certain molecules. And you can try to assign these all of these lines. 221 00:24:53,710 --> 00:25:05,230 And if you have enough left catalogues of lines and you find that we find see both simple and also rather complex molecules present in these clouds. 222 00:25:05,590 --> 00:25:10,360 So this whole feature, this whole pattern of lines is all due to one molecule, methanol. 223 00:25:11,380 --> 00:25:14,380 But you also see simple molecules like sulphur dioxide. 224 00:25:14,410 --> 00:25:18,010 Several lines over here and more complex molecules like that. 225 00:25:18,010 --> 00:25:25,360 Methyl aether or metal formate. You also can get some kinematic information from the lines here. 226 00:25:25,360 --> 00:25:29,610 You see how beautifully resolved this line profiles are. This is a case of water. 227 00:25:30,030 --> 00:25:36,600 And you see already that this water is is moving actually very fast, up to 100 kilometres per second. 228 00:25:36,870 --> 00:25:39,720 So we also get some information on the the kinematics. 229 00:25:40,620 --> 00:25:46,740 So just to summarise, that's the kind of information that we can actually get here from these these lines. 230 00:25:47,700 --> 00:25:49,979 We get information on the kinematics, 231 00:25:49,980 --> 00:25:58,320 we get from the line intensities we can and count basically how many molecules there are and translate that into relative abundances. 232 00:25:58,740 --> 00:26:09,420 And then from the line ratios, they tell us something how often a molecule colitis and not a molecule in order to get its excitation. 233 00:26:09,420 --> 00:26:14,190 And that tells us something about physical conditions like temperatures and densities in this class. 234 00:26:14,910 --> 00:26:19,290 So these kinds of data, these kind of spectra actually contain a whole wealth of information. 235 00:26:19,530 --> 00:26:22,140 This which you can characterise the class. 236 00:26:24,110 --> 00:26:31,730 Just to show you some of the molecules that have been detected, some of the complex, more complex organic molecules. 237 00:26:32,270 --> 00:26:37,670 And here is already that methyl aether that I mentioned. 238 00:26:38,510 --> 00:26:43,790 So one of the simple sugars that's I'll be talking about a little later as well, 239 00:26:45,080 --> 00:26:53,479 that glycol aldehydes that is seen ethanol is seen in quite a substantial abundances actually in these clouds. 240 00:26:53,480 --> 00:27:03,879 And molecules like benzene have also been detected. But if you think of molecules that we would need to to say this is prebiotic material 241 00:27:03,880 --> 00:27:10,300 that we would need to to make a DNA and RNA of potential life elsewhere in space, 242 00:27:11,140 --> 00:27:19,480 I can think of simple amino acids like lysine or bases like Purine and Pyrimidine, and these have all not yet been detected in space. 243 00:27:19,480 --> 00:27:26,050 There have been many claims and there was it the the refereed literature in the press that this molecule has been detected. 244 00:27:26,440 --> 00:27:33,970 But so far that has not yet been formally seen. But this is exactly what's what Alma will do, because it will have such high sensitivity. 245 00:27:34,180 --> 00:27:39,910 It will actually be short being able to show how far it is, chemical complexity and actually go. 246 00:27:40,990 --> 00:27:48,549 And this little molecule here, caffeine, although not necessarily for the origin of life, is certainly necessary for the maintenance of life. 247 00:27:48,550 --> 00:27:53,980 So and that's the molecule that we also still have not yet discovered in space, 248 00:27:53,980 --> 00:27:58,750 that it's actually not much more complex than some of the molecules that have been seen. 249 00:27:58,750 --> 00:28:06,190 So who knows what we will find? And even larger molecules are presence in space. 250 00:28:06,190 --> 00:28:12,160 I mentioned already this polycyclic aromatic hydrocarbons which have a very characteristic infrared emission. 251 00:28:12,520 --> 00:28:23,540 In this case, we don't know exactly the precise molecule that we have, whether it has 50 carbon atoms of 40 or 60, and how many hydrogen star. 252 00:28:24,040 --> 00:28:27,070 But we know as a class that these molecules are certainly present. 253 00:28:27,970 --> 00:28:33,760 A very recently actually also the first Fullerene C 60 and 70 were actually discovered in space. 254 00:28:34,390 --> 00:28:43,090 Of course, Harry Kroto was originally a master chemist and he got much of his inspiration for his work on C60 from working on these interstellar 255 00:28:43,090 --> 00:28:50,950 molecules and and wondering if you have these long carbon chains and you start to wind them up and basically what kind of molecules he gets. 256 00:28:50,950 --> 00:28:55,540 And that's one of the the roads that led him to the discovery of C60. 257 00:28:58,300 --> 00:29:05,110 So far I've been talking mostly as molecules, as a gas, but actually because these grains are so cold today, 258 00:29:05,320 --> 00:29:11,980 they sort of act as a deep freeze and on which molecules from the gas can basically collide and stick, 259 00:29:12,370 --> 00:29:16,420 much like you can get icy your freezer or in the cold winter nights, 260 00:29:16,750 --> 00:29:22,060 you get molecules from the atmosphere that freeze out on your windshield and form a little icy layer. 261 00:29:23,420 --> 00:29:28,100 Now, once the molecules and the atoms are on the grains, then other chemical reactions can occur, 262 00:29:28,430 --> 00:29:31,730 especially as reactions with hydrogen become much more prominent. 263 00:29:32,030 --> 00:29:37,909 So you can turn actually oxygen into water and you can turn carbon into methane, 264 00:29:37,910 --> 00:29:44,090 and you could turn nitrogen into ammonia and carbon monoxide, which is another main ingredient of this cloud. 265 00:29:44,100 --> 00:29:47,210 You can actually hydrogenase it all the way to methanol. 266 00:29:47,840 --> 00:29:57,050 And that's actually one of the reasons why medicine all is so prominence, why methanol plays a very important role in that and interstellar chemistry. 267 00:29:58,790 --> 00:30:05,390 So actually enlightened in the sexual laboratory by trying to simulate these processes. 268 00:30:05,790 --> 00:30:09,320 And of course, we can never simulate all the conditions we need to speed it up. 269 00:30:09,330 --> 00:30:13,070 We cannot wait for four times of the five years for our reactions to occur. 270 00:30:13,700 --> 00:30:22,579 And that's certainly the temperature we can that a beacon and also basically make sure that we 271 00:30:22,580 --> 00:30:28,730 only look at and say to body processes that we can actually extrapolate to much longer timescales. 272 00:30:29,960 --> 00:30:36,740 And so the laboratory is now actually under the direction of Hydrothermal March and we are doing still continue 273 00:30:36,740 --> 00:30:42,290 to collaborate on a number of processes that are directly relevant for what is happening in interstellar space. 274 00:30:43,520 --> 00:30:47,749 So that's an example of we actually tell you the story about water, because water is, 275 00:30:47,750 --> 00:30:55,190 of course, one of the main ingredients for for life on other planets. 276 00:30:56,280 --> 00:30:58,710 And thanks to the Herschel Space Telescope, 277 00:30:58,950 --> 00:31:07,109 we've now been able to obtain quite unique data on what it can tell us and give us insights into questions such as 278 00:31:07,110 --> 00:31:14,430 how and where water is formed and how it is actually transported from a collapsing cloud onto a forming planet. 279 00:31:15,710 --> 00:31:22,910 So just to show you that this is not just interesting for astronomers, you see quite a lot in the popular literature. 280 00:31:23,380 --> 00:31:27,050 And this is challenges for life on Mars. And it says just at water. 281 00:31:27,700 --> 00:31:36,259 And here is actually what they think, that the NASA's spacecraft, when it finally gets to a new planets, they will actually see in terms of water. 282 00:31:36,260 --> 00:31:40,640 So it simply shows the importance of water in all of the story. 283 00:31:43,250 --> 00:31:47,180 So the program that we have been carrying out over the last several years is dead 284 00:31:47,180 --> 00:31:51,620 in the water in star forming regions with Hershel program abbreviated as wish. 285 00:31:52,780 --> 00:32:00,470 And she says it's one of these large collaborations that we now have in astronomy where you actually get a 286 00:32:00,620 --> 00:32:07,370 quite a number of hours in this case of guaranteed observing time as a return for building the instruments. 287 00:32:08,330 --> 00:32:14,510 And then we have less clear collaboration between some 70 scientists from 30 institutions. 288 00:32:14,810 --> 00:32:17,840 And that's done carry out this joint program. 289 00:32:19,180 --> 00:32:27,520 And so we're now in the States that we have all the data, but we are still digesting sort of all of the results that I think that we now 290 00:32:27,520 --> 00:32:32,710 have a much better view as to how we think actually that water is is formed. 291 00:32:33,010 --> 00:32:37,180 And really, look, not most of it actually happens on these dust particles. 292 00:32:37,900 --> 00:32:45,670 So what you see here is a global dust grain where maybe once a day you see a the hydrogen atom actually lands on this grain. 293 00:32:45,910 --> 00:32:51,690 You also see the oxygen atoms, the hydrogen atoms find each other and take off as a hydrogen molecule. 294 00:32:51,700 --> 00:32:57,790 But you can also form a water molecule there. And here you see already another two molecule actually being formed. 295 00:32:58,240 --> 00:33:02,950 And now they're making the hydrogen peroxide radical. If you make hydrogen peroxide. 296 00:33:02,950 --> 00:33:06,190 Yes. Here. And we actually form a water molecule. 297 00:33:07,410 --> 00:33:11,330 And these were all processes. That's where we zoom forward in time, 298 00:33:11,340 --> 00:33:22,080 fast forwards and that's then how we make our our ice layer actually on the brain and then end up actually with an is an icy grain. 299 00:33:23,480 --> 00:33:25,879 So a lot of these processes are actually pushing AIDS. 300 00:33:25,880 --> 00:33:36,770 It's already 30 years ago, but we simply didn't have the laboratory experiments in order to test these these hypotheses. 301 00:33:37,130 --> 00:33:47,600 And it's really, I think, a success story of the interaction between astronomy and laboratory astrophysics that we've now been able to to to verify 302 00:33:47,600 --> 00:33:53,900 all of these processes in the lab and actually show also how they occur and measured are rate the rate constants. 303 00:33:55,620 --> 00:34:05,910 So we can then try to to quantify this down and look, for example, at here, what is this dark cloud and why we know that we have mostly ice in there. 304 00:34:06,360 --> 00:34:07,290 And then we can say, well, 305 00:34:07,290 --> 00:34:15,960 the water that we can actually see in the gas is basically a balance between the formation of water on this ice that I just showed you, 306 00:34:16,260 --> 00:34:22,079 and then getting the molecules back of the grains again back into the back, into the gas phase. 307 00:34:22,080 --> 00:34:29,040 And that should then give us our signal in terms of of water that we get from this from this cloud. 308 00:34:30,780 --> 00:34:34,079 And that's indeed what we have observed as part of the wish program. 309 00:34:34,080 --> 00:34:41,250 We have now detected for the first time basically that the Colt gaseous water reservoir is Herschel. 310 00:34:41,430 --> 00:34:49,830 And one of these clouds, probably a cloud of is on the verge of forming of collapsing and forming a new solar system. 311 00:34:50,670 --> 00:34:59,700 And the signal that we see here is very much in agreement with sort of this theory of water formation and desorption that I just sketched to you. 312 00:35:00,480 --> 00:35:05,430 So it looks like we have learned a lot about the water formation in space. 313 00:35:06,540 --> 00:35:10,530 It's also clear that the bulk of the water is already formed during this early stage. 314 00:35:10,890 --> 00:35:15,930 So the water molecules that you see here in this glass and it's may well be the water 315 00:35:15,930 --> 00:35:19,860 molecules that were formed some four and a half billion years ago in the cloud, 316 00:35:19,860 --> 00:35:25,950 out of which our own solar system formed. So that's an interesting thought to keep to conclusion. 317 00:35:27,660 --> 00:35:33,090 And we also see the water associated with the forming Protostars. 318 00:35:33,090 --> 00:35:36,540 Here is still some beautiful example of the quality of the data that we're getting, 319 00:35:37,490 --> 00:35:43,560 and it tells us that some of the water is not only in falling, but some of the water is also outflowing. 320 00:35:44,070 --> 00:35:46,980 There's very high velocities at 200 kilometres per second. 321 00:35:47,220 --> 00:35:54,180 And in fact, we see the water associated with these jets that we that are associated with old forming stars. 322 00:35:54,540 --> 00:35:59,339 And we can now even make maps of of water associated with forming stars. 323 00:35:59,340 --> 00:36:06,780 So here is the protostar basically. And there you see the outflows to bipolar outflows which are lighting up in water. 324 00:36:07,080 --> 00:36:15,150 So basically what you're seeing here is maybe a young version of what our own solar system also looked like at some early stage. 325 00:36:15,450 --> 00:36:19,920 Very it had basically these these water fountains on both sides. 326 00:36:20,160 --> 00:36:23,220 So this is basically where the water is, is lighting up. 327 00:36:24,800 --> 00:36:35,060 So to summarise so far interest, our clients clearly have a very rich chemical composition in spite of the very cold and tenuous conditions and 328 00:36:35,060 --> 00:36:41,270 complex molecules and water are basically found around nearly all the forming stars and throughout the Milky Way. 329 00:36:41,750 --> 00:36:43,760 And this means that at least the ingredients, 330 00:36:44,570 --> 00:36:53,240 the building blocks for prebiotic material are widespread throughout our Milky Way and presumably also through other galaxies. 331 00:36:54,850 --> 00:37:04,600 All right, so let's now form a star out of these clouds. And I'm going to look a little bit more at the physics and effects just collapsing. 332 00:37:04,600 --> 00:37:12,850 And then forming a star is not so simple. There's a lot of physics that is actually associated with it, which I won't go into during this lecture. 333 00:37:13,120 --> 00:37:21,819 I just want to show it to you here in a movie that is actually based on real data from the Hubble Space Telescope 334 00:37:21,820 --> 00:37:29,950 taken by Chris O'Dell and then turned into a movie and basically taken the data making from the two dimensional image, 335 00:37:30,040 --> 00:37:35,440 three dimensional image through which you can then zoom in and in a computer. 336 00:37:35,710 --> 00:37:43,900 And here we now go to an animation where you actually see this envelope around the collapsing star. 337 00:37:43,900 --> 00:37:53,500 And here you see to the young star itself was a rotating disk of gas and dust and is this disk in which the planets can subsequently form. 338 00:37:54,520 --> 00:37:59,320 So let's look at this once more. Here we have our two dimensional image again of Orion. 339 00:37:59,710 --> 00:38:01,240 We're going to now fly through it. 340 00:38:02,500 --> 00:38:09,639 And so what you see is already several of these protostars of collapsing clouds in which a new star is already being born. 341 00:38:09,640 --> 00:38:12,010 They're still embedded in their envelopes. 342 00:38:12,460 --> 00:38:21,730 And these envelopes are basically blown away by these by these jets and also by the radiation from the young stars in the surroundings. 343 00:38:22,000 --> 00:38:25,660 And here we now go to the animation. The envelope is basically being dispersed. 344 00:38:26,170 --> 00:38:28,270 And what we see now is still the young star, 345 00:38:28,270 --> 00:38:38,740 but it's surrounded by this this rotating disk of gas and dust and in which the subsequent planets can form. 346 00:38:40,060 --> 00:38:48,420 And such a rotating disk is a very natural outcome of a collapsing cloud that has initially a little bit of rotation to go with. 347 00:38:49,720 --> 00:38:56,170 So here you see the still image from Hubble on which the movie was based. 348 00:38:56,530 --> 00:39:04,120 And you see already that you have to look really was a magnifying glass in order to see these young stars, Mr. Disks, surrounding them. 349 00:39:04,120 --> 00:39:08,410 And then we can see them here as silhouettes against a bright background. 350 00:39:08,830 --> 00:39:15,580 But these images, which are here by now, almost two decades old, were still very important to show the sizes of these disks. 351 00:39:16,060 --> 00:39:23,180 And because you can now put our own solar system at a distance of Orion and you can show that is very much the same size. 352 00:39:23,180 --> 00:39:27,249 So showing that these disk actually have sizes that are equivalent, 353 00:39:27,250 --> 00:39:33,760 so to say the distance from centre of Pluto, which is some some 40 astronomical units. 354 00:39:34,990 --> 00:39:41,830 So what we now know is that nearly all the young stars in the in their surroundings are have 355 00:39:41,830 --> 00:39:48,190 these disks and that the sizes of the disks are comparable to the sizes of our own solar system, 356 00:39:48,640 --> 00:39:53,860 and also that the masses of these disks are usually enough to form a solar system. 357 00:39:54,850 --> 00:39:59,890 And that is about 1% of the mass of the sun, or about ten times the mass of Jupiter. 358 00:40:00,130 --> 00:40:03,190 If you think about how much mass you needed to make our own solar system, 359 00:40:04,150 --> 00:40:12,070 that's about ten times the mass of of Jupiter, because some gas has been lost from the solar system during formation. 360 00:40:13,120 --> 00:40:17,320 So this means also that our ingredients actually for planet formation are gone. 361 00:40:18,370 --> 00:40:22,180 That is also something that we're finding throughout. 362 00:40:24,490 --> 00:40:28,630 Okay. So but what is the problem? Well, here we go back to our Carina Nebula. 363 00:40:29,050 --> 00:40:34,300 And here we see these clouds and these we can easily resolve this current instrumentation. 364 00:40:34,870 --> 00:40:41,860 And even the collapsing forest is collapsing regions. We can also still resolve this current instrumentation. 365 00:40:42,190 --> 00:40:48,819 But if I take a here a disk and this is an artist's impression of a disk, then I wish it was as big as this on this scale. 366 00:40:48,820 --> 00:40:51,430 But it is not. It's much smaller. 367 00:40:51,430 --> 00:40:58,990 So basically if you would look at what the disk would be, it would really be sort of tiny, tiny, tiny on this on this scale. 368 00:41:00,790 --> 00:41:06,459 And so this is really why we need an instrument like Alma to basically zoom in on these 369 00:41:06,460 --> 00:41:12,850 regions and to have the sharpness in order to to study these to study these disks. 370 00:41:14,490 --> 00:41:19,410 So let's look a little bit about what we now know about these about these tests. 371 00:41:20,400 --> 00:41:27,210 First, let's talk a little bit again about our water story, because water plays an important role in planet formation. 372 00:41:27,900 --> 00:41:37,070 We know that in our solar system and also in other solar systems, there is the so-called snow line, which Stewart says already. 373 00:41:37,080 --> 00:41:42,220 It's the line beyond which water actually exists as an ice. 374 00:41:42,240 --> 00:41:51,300 Or you can also call it Iceland. And that is sort of close to where Jupiter is, a little bit more inward. 375 00:41:51,990 --> 00:41:58,110 Currently, within the early solar system, it was somewhere around where Jupiter now is. 376 00:41:59,400 --> 00:42:05,410 And if you actually freeze out water and then you enhance the density of the solids and 377 00:42:05,430 --> 00:42:11,760 that makes actually that's your whole planet formation process is actually more rapid. 378 00:42:12,180 --> 00:42:21,360 And they are trying to basically get from these small dust particles to a larger and larger dust particles, the inner parts inside the ice line. 379 00:42:21,360 --> 00:42:26,910 That's where water is mostly as a gas, and that's also where the water gets very hot. 380 00:42:27,840 --> 00:42:36,180 And that is water that we can actually observe is other telescopes and more infrared telescopes in this area, the Herschel and the Alma telescopes. 381 00:42:37,440 --> 00:42:44,730 And so what we've actually been trying to do is we have been trying to use Herschel in order to detect a water gas, 382 00:42:45,420 --> 00:42:51,030 because that is actually providing us with a direct measure of how much Easter 383 00:42:51,030 --> 00:42:55,530 is as through the same sort of processes that I illustrated you earlier for. 384 00:42:55,530 --> 00:43:01,120 It is collapsing. Cloud and ice itself is very difficult to detect in these climate. 385 00:43:02,010 --> 00:43:04,680 And so this is one of the highlights of our wish program, 386 00:43:04,680 --> 00:43:14,460 also the detection of cold water in these disks and shown here from work from if you look ahead as well. 387 00:43:15,510 --> 00:43:21,950 And the signal actually, we can translate into a number of water molecules are there. 388 00:43:21,960 --> 00:43:26,970 And since Science magazine likes it, mostly the units of oceans. 389 00:43:27,210 --> 00:43:32,510 We translate this into oceans of water, which is about 6000 oceans. 390 00:43:33,000 --> 00:43:37,010 And but you can, of course, translated also into grams or whatever. 391 00:43:37,020 --> 00:43:39,900 And I can give you the conversion factor for that. 392 00:43:40,920 --> 00:43:48,630 But it shows already that this disk contains certainly enough water to fill several oceans on a on a new planet. 393 00:43:50,450 --> 00:43:57,800 The other thing that we've done is we've used actually, Oliver. These are data that were released by the project as science verification. 394 00:43:58,130 --> 00:44:01,730 Basically, the project was trying to see whether Alma was working well. 395 00:44:01,730 --> 00:44:08,360 And we had some old data showing these three lines here. And so they took these data and they said, oh, we see these three lines. 396 00:44:08,360 --> 00:44:13,489 That's great. Alma is working fine. And that's even in its early stage. 397 00:44:13,490 --> 00:44:16,490 When this was still done, there's only 16 antennas. 398 00:44:16,890 --> 00:44:26,270 Alma was already so sensitive that it's not just these three lines, but it saw a whole bunch of other lines already appearing here in these data. 399 00:44:26,750 --> 00:44:30,350 And together with zero consent from the University of Copenhagen, 400 00:44:30,350 --> 00:44:37,460 we dug into these data and we discovered quickly that several of these lines were due to interesting molecules, 401 00:44:37,670 --> 00:44:47,959 actually quite complex organic molecules. What we're looking at here is a forming protostar, a very low mass protostar and not seeing as big as Orion. 402 00:44:47,960 --> 00:44:51,500 But just a tiny little start is forming at the moment. 403 00:44:51,920 --> 00:45:00,469 And this tiny little star already has very complex molecules associated with it and even quite complex ones like this. 404 00:45:00,470 --> 00:45:05,540 There's little sugar here, like, well, aldehydes and we're over. 405 00:45:05,810 --> 00:45:15,860 Oh, my God. Already see? So sharp and that we could locate the presence of these molecules to within 25 astronomical units from the source. 406 00:45:16,280 --> 00:45:21,740 So now we're no longer looking at large scales? No. Now we're looking really on scales of these disks. 407 00:45:22,910 --> 00:45:26,720 Well, basically corresponding to the orbit of Uranus. 408 00:45:27,080 --> 00:45:36,020 And we are finding already these complex molecules there. So what we're seeing is that they're both with Herschel, but now particularly with Alma, 409 00:45:36,260 --> 00:45:47,060 we are able to really zoom in and to these disks in which planets are forming and that we can actually characterise these and their composition. 410 00:45:49,600 --> 00:45:57,070 Okay. Back to a little bit of arch. What you see here is actually a English engraving from 1798, 411 00:45:57,970 --> 00:46:04,959 which is actually hanging in our living room and reminding us that's already decked as what is it? 412 00:46:04,960 --> 00:46:11,560 Centuries ago, artists were speculating that our solar system is just one of many, 413 00:46:12,100 --> 00:46:16,450 and that is our solar systems don't need to look at all like our own solar system. 414 00:46:17,710 --> 00:46:24,010 Some of them have less planet, some of them have more planets, some of them are close by and some of them are further away. 415 00:46:25,110 --> 00:46:34,920 And this is exactly what is now being revealed by these detections of exoplanets, that there is a huge diversity in planetary systems. 416 00:46:36,030 --> 00:46:44,370 And so that's, for example, at the Kepler satellite and is is finding a huge diversity in in planets. 417 00:46:45,850 --> 00:46:52,930 So. But where does this come from? Well, the answer lies clearly in the past, during the time that these were assembled on this planet. 418 00:46:53,500 --> 00:47:02,620 And that happened really in the disks and these rotating these through Hunter young stars, which contain a material out of which they they formed. 419 00:47:03,790 --> 00:47:08,170 So in a very simplistic way, what is happening is that this gas and dust, 420 00:47:08,590 --> 00:47:13,270 you know, that came from this collapsing cloud and that's entered into this desk. 421 00:47:13,600 --> 00:47:23,290 So of which we now know the ingredients that basically these small dust particles started to coagulate and grow and grow into larger particles. 422 00:47:24,220 --> 00:47:27,010 This is not as simple as it looks here in this cartoon. 423 00:47:27,010 --> 00:47:35,049 And in fact, in my seminar tomorrow in the astronomy department, I will tell a lot more about these digital processes. 424 00:47:35,050 --> 00:47:41,860 And what we are learning about is at the moment as to how these various particles can of coagulate. 425 00:47:43,870 --> 00:47:47,079 But it's clearly happening and some of that we can actually see in action. 426 00:47:47,080 --> 00:47:57,219 And these are some first results from the AMA, again, on these discs in which we think that actually planet formation is occurring at this moment. 427 00:47:57,220 --> 00:48:00,520 So this is an artist's impression where we see one of these dusty disks, 428 00:48:01,240 --> 00:48:07,180 but then some of these holes here, which are two locations in which if I go back here, 429 00:48:07,510 --> 00:48:10,420 an image of planets may have formed already, 430 00:48:10,630 --> 00:48:19,450 and which is basically clearing out its past by attracting the gas and the dust and thereby creating this gap here in these disks. 431 00:48:19,750 --> 00:48:27,130 We cannot see the young planet itself, but we can certainly see the result of what it has done that they re creating this this gap over here. 432 00:48:28,270 --> 00:48:35,230 And we are now starting to see this precedent of sharpness, actually, and these these gaps and holes in these disks. 433 00:48:35,710 --> 00:48:42,670 And there are some surprises associated with that. So that I will tell you more about again tomorrow. 434 00:48:44,640 --> 00:48:50,520 Okay. In the last few minutes, let me make the connection done with our own early solar system. 435 00:48:50,520 --> 00:48:55,460 And let's go back to comments. Let's go back to comments like comets, Halley. 436 00:48:55,580 --> 00:49:05,989 Halley's Comet or Comet Hale-Bopp. A beautiful example, a very bright comets in 2005, a new comet that is coming back of a ten stars. 437 00:49:05,990 --> 00:49:12,020 That's Will and maybe somewhat later in the year will be actually visible. 438 00:49:13,580 --> 00:49:17,930 And the good thing is that we now have these powerful telescopes that we can 439 00:49:17,930 --> 00:49:23,630 actually point at these comets and that we can then study their composition. 440 00:49:24,170 --> 00:49:35,780 So what are comets? Comets are basically these coagulated and icy dust grains and grown to something like a kilometre in size or a few kilometres 441 00:49:35,780 --> 00:49:45,050 in size and which have most of their time spent in the outer parts of our solar system where it was very cold and radical, 442 00:49:45,060 --> 00:49:53,480 basically be preserved. So we think that comets actually contain the most original primitive material that we have in our solar system. 443 00:49:53,480 --> 00:49:59,900 And so they tell us also something about the past. They tell us the story basically also of the formation of our own solar system. 444 00:50:00,740 --> 00:50:09,710 And so we can now point our powerful telescopes at this comets and study their chemical material that they have. 445 00:50:10,040 --> 00:50:16,180 And what we find actually is that the chemical composition is actually very comparable to what we see is these 446 00:50:16,190 --> 00:50:23,060 interstellar ices suggesting that these are indeed sort of a leftover of the formation process of our own solar system. 447 00:50:23,330 --> 00:50:31,460 So that basically they're the building blocks that didn't make it into comets are scattered down into the outer solar system. 448 00:50:33,580 --> 00:50:38,620 We can actually make time to make some connections and also what we see on Earth. 449 00:50:39,290 --> 00:50:44,859 There is one big question there, namely whether comets actually did bring the water on earth. 450 00:50:44,860 --> 00:50:48,879 Where does the water on earth actually come from? And again, thanks to high five, 451 00:50:48,880 --> 00:50:57,130 we have another part of this story because high fire Herschel could observe not just water but also refrigerated version, 452 00:50:57,130 --> 00:51:05,230 a video where one hydrogen is replaced by a heavier version of hydrogen deuterium. 453 00:51:05,710 --> 00:51:13,690 And it's actually this ratio which would then go compare with the ratio that we have of water in the oceans glass. 454 00:51:14,410 --> 00:51:23,320 And that is thought to be a diagnostics of what's the. What did the original materials that brought us water on the earth? 455 00:51:24,220 --> 00:51:36,760 And what Herschel actually found is at least two comets in which this ratio is within 20%, exactly the same as we have in water in our own oceans. 456 00:51:36,970 --> 00:51:41,890 Previously, there have been measurements that suggested at least two factor of two discrepancies, 457 00:51:41,890 --> 00:51:47,290 but that factor of two has gone away with these new measurements suggesting that Reza's least one 458 00:51:47,290 --> 00:51:53,050 family of comets that has the right isotopic composition and could have delivered the what on earth? 459 00:51:54,070 --> 00:51:58,060 Now you may already think of delivering water on earth. How does that how does that work? 460 00:51:58,950 --> 00:52:05,770 And because if you have an impact, then a lot of things can, of course, happen. 461 00:52:06,640 --> 00:52:17,320 And in fact, if you have a massive impact of a very big object and maybe a mars sized object that impacted our own early Earth, 462 00:52:18,040 --> 00:52:26,140 then it's clear that not much of the water and organic material that is present in these comments that as would actually survive. 463 00:52:27,280 --> 00:52:34,390 We think that actually an impact phenomenon like this was responsible for the formation of of our own moon. 464 00:52:35,620 --> 00:52:40,930 And so you don't need to do this. You should not do it this way, because then there's not that much is left. 465 00:52:41,430 --> 00:52:44,620 And so you do try to do it a little bit more gently. 466 00:52:44,620 --> 00:52:51,800 So not larger comets and and maybe sort of having the comet disintegrating and 467 00:52:51,940 --> 00:52:56,950 bring it in in smaller pieces on Earth so that it's so dense can still survive. 468 00:52:57,190 --> 00:53:02,580 But this is obviously also still one of the big questions as to how you make this this work and. 469 00:53:02,680 --> 00:53:08,040 Exactly. Finally, if you want to link down with exoplanets. 470 00:53:08,490 --> 00:53:14,940 And then the next step in this research is basically to look for the chemical ingredients, 471 00:53:14,940 --> 00:53:21,720 not just of the star forming regions or the planet forming regions in which the stars and planets are being made. 472 00:53:21,960 --> 00:53:27,060 But to actually look at mature planets and look there at their chemical compositions. 473 00:53:27,360 --> 00:53:32,370 And so this is deep echo for the next generation of optical infrared telescope, 474 00:53:32,370 --> 00:53:36,509 such as the extremely large telescope that has to actually have power to take 475 00:53:36,510 --> 00:53:42,090 spectra of these of these exoplanets and determine the chemical composition. 476 00:53:42,840 --> 00:53:47,129 I think one of the main messages of my story after this lecture, actually, 477 00:53:47,130 --> 00:53:53,350 is that a lot of this chemical composition can and is already determined at the time of their formation, 478 00:53:53,370 --> 00:54:00,000 only at a location in the disk where they being formed, whether they were formed inside a snow line or outside the snow line. 479 00:54:00,900 --> 00:54:04,890 And the same actually for the carbon rich material. 480 00:54:06,600 --> 00:54:11,490 So we found the entries, this summary. We started off as clouds. 481 00:54:11,940 --> 00:54:15,210 We saw that they have actually a very rich chemical composition. 482 00:54:15,570 --> 00:54:23,400 You see that out of these clouds and they can collapse to form a young star in that these young stars are surrounded by disks. 483 00:54:23,700 --> 00:54:28,410 We are now starting to determine the chemical composition of this material here in this disks. 484 00:54:29,160 --> 00:54:32,710 We know that's out of these disks through the coagulation of the grains. 485 00:54:32,740 --> 00:54:39,059 You can actually form planets. And much of the same material that we had here is actually transported to these disks, 486 00:54:39,060 --> 00:54:46,830 is also transported to the icy bodies in these new solar systems, such as you see over here. 487 00:54:47,790 --> 00:54:53,040 And some of that material can indeed and also have been brought onto these new planets. 488 00:54:55,010 --> 00:55:03,079 Of course it's to her. Also, our son doesn't have eternal life, so at some stage they will run out of nuclear fuel and they will die of that. 489 00:55:03,080 --> 00:55:08,660 They will swell and they will come much, much bigger. They will swallow basically much of our solar system. 490 00:55:09,110 --> 00:55:18,170 They will also then return some of the heavy elements that they made in their nucleus through nuclear burning and like carbon, oxygen and hydrogen. 491 00:55:18,530 --> 00:55:24,380 And they bring that back to the interstellar medium and then a whole new cycle of star formation, 492 00:55:24,560 --> 00:55:28,670 climate formation, and then stellar deaths, planetary deaths, and start again. 493 00:55:29,030 --> 00:55:34,100 And of course, in our own Milky Way, the cycle has occurred already several times. 494 00:55:35,650 --> 00:55:43,510 So to sum up then chemical ingredients and our present storage space and they are associated 495 00:55:43,510 --> 00:55:49,329 with this way all the forming stars transfer systems are possible under majority of stars, 496 00:55:49,330 --> 00:55:52,750 whether they actually form. And it's still a bit of a question, 497 00:55:52,750 --> 00:55:59,380 although the exoplanet statistics seem to indicate that at least one planets per star is certainly 498 00:55:59,440 --> 00:56:08,440 the possibility and formation process is now being actually unravelled based in new telescopes, 499 00:56:09,010 --> 00:56:12,069 the new instrumentation, they're basically driving to science. 500 00:56:12,070 --> 00:56:18,970 Herschel Alma And our next goal is really to image the physics and chemistry on these solar system scales. 501 00:56:20,130 --> 00:56:25,050 So I'll leave you with the thought of bringing art and science and astronomy again together. 502 00:56:25,620 --> 00:56:36,210 And the Australian Aboriginals already had a milky Way dreaming and comets featured already in some of the dreams that you see of the artists. 503 00:56:36,600 --> 00:56:41,309 As astronomers, we have dreamt for more than 30 years we've dreamt of Herschel, 504 00:56:41,310 --> 00:56:47,250 we've jumped of Alma and now these facilities are with us and are doing fantastic science visit. 505 00:56:47,670 --> 00:56:48,420 Thank you very much.