Good afternoon, everybody. I apologise for the delay. So first, I would like to welcome you to the 16th lecture. As you know, the lecture series is one of the many activities that is being supported by the Cancer Family Charitable Foundation. So very big thank you to Sir Michael and Lady Dorothy Hinson for their support over the years.
So of course, our speaker tonight, we're very delighted to have Professor Brendan Doyle from the University of Montreal, known locally of course as the when you see them all well so. And he is director of the institute. I need to get this right the Institute for Research on Exoplanets as well as the Omega Antique Observatory. The Omega Arctic Observatory operates a smallish telescope, but is a very effective platform, in fact, for instrument development.
And you'll see that that Aeneas made a name for himself by developing innovative, cutting edge instrumentation. And that telescope is really a precious resource for those instrument development efforts. So actually, Rodney started his career not too far away from here.
He got this from Imperial College in London in 1990 and then moved back to Montreal fairly early on and was a post-doctoral fellow there and a research associate before getting what is called a Canada research chair that is offered by the National Science and Engineering Research Council of Canada, the equivalent of The New Yorker I here in the UK. And that is meant actually to promote links, I guess between academia and industry. So that's where the incidental development comes about.
And after that, he moved on to a professorship at the university. And as we'll hear today, his fame, I guess, really started ten years or so ago when he probably made his biggest discovery. So I think was the first person to take a direct image of a planet around another star. And that was, in fact, the combination, again, of very effective and ingenious instrumental development. So we'll hear undoubtedly about this today. In fact, he's been involved in many instrumentation efforts.
His babies, as he says now, are the instrument, spittle and nips, one on the left hand side telescope in Hawaii, the other on a 3.6 metre at the Sea Observatory in Chile and is all about high resolution spectrograph to detect and characterise exoplanets using the so-called radial velocity method, which I suspect we'll hear about as well today. He's also involved in an instrument on the Gemini telescope.
Of course, the UK is a partner along with Canada and the US in operating that scope and is developing a planet imager for that. And perhaps his biggest expectation now is is involved with the James Webb Space Telescope, the successor to Hubble in an instrument called NEAREST that again aims to characterise exoplanets. So I'll just mention a few prizes and then we'll move on.
So here's one, in fact, the the polonium prize song from NASA, again, this Canadian Research Council, as well as the 2009 prize from the American Association for the Advancement of Science and the National Medal of the National Assembly in Quebec, amongst other things. So anyway, without further ado, here is an and he will tell us about the quest for nearby habitable world.
So thank you very much. Many thank you, Malcolm. It's really a great pleasure and a great honour to be here today to talk to the subject, which I you know, I have to be honest, I've never I've not always studied exoplanets. I started my my career as not to mentioned as an actual galactic astronomer. So but it's like in 1995 when the very first time it was discovered, that was really a turning point for me.
So today I'm going to talk to you about this quest, this quest about finding habitable worlds that is planet that are potentially inhabited by my life. So that's the main question I wish try to answer. It's a long term question. I'm not going to it's not going to happen any day. But I, I think I hope I can do to you that we may have an answer to this in a few decades.
So many of you will probably see that for me, not within my professional lifetime or probably by my late, my and my courage when that happens. But it will happen. We will likely see that discovery. So but just to be clear about what I'm going to talk about, why don't we mention about we mentioned life.
You probably have all kinds of a picture and in your mind you're thinking in bacteria, you know, little plants, animals, and of course, you're probably thinking of the most powerful species on earth. Right. Those people. Right. Or perhaps that species. Right. Or perhaps you have another idea about life outside the solar system. Those guys. I'm not going to talk about those. No, that would be a fantastically fine, intelligent life.
That's not what I'm going to talk about. I'll we'll talk about a more modern life bacteria that have an influence on on their on a planet on earth. The the oxygen is produced by by plants. CO2 is produced by by us. Methane is really coming from cows. And so this is what we're trying to do. So it's the plan is to detect a biosignature, trying to detect the effect of life in its on its atmosphere.
And that's the main goal, detecting the atmosphere of an exoplanet and actually measuring its chemical composition. As you can see, as you will see, it is very hard, but that what we're rapidly reaching humanity is reaching the technological maturity to actually do this. Okay. So there's no there's no speculation about the fact that these exist. It's not a scientific fact. And it's so many possibilities.
We're estimating there's probably tens of billions of habitable planets in our own galaxy, and probably the closest one is in our in the start to just us at four and four like years. So what we're looking for is something that looks like us, a rocky planet with water on it and an atmosphere that's key, again, to actually to hope to detect a biosignature. So and we're also looking for a planet at the right place around there, star.
That's what we call the habitable zone is this distance not too far, not too close to the star so that you can hope to have liquid water at the surface of the planet. Now, the the question of the planet being habitable is a very complex one. It's just it's much more complex than this simple criteria of finding where the star is next to the star.
But that's the first thought. That's the very first thing we can do. We can actually there's so many whole planet, so we can choose those that are most likely inhabited and we're concentrating on those that are within their habitable zone. Okay. So how do we detect is it possible to do it live from afar? So imagine you are on the moon during a moon eclipse. So in face of all these would be completely dark. It's not dark.
You can watch the moon, it's actually red. And that's because of the atmosphere. The atmosphere is filtering light from the sun. And if you are on the moon with a spectrograph, something that measure that bisects light into its colour, that we express in wavelength, this is what you would see. So you'd see, you know, this is the visible part. This is the infrared part. And all these wiggles are the spectral signature of molecules.
So if there's one that is mind boggling, it's the O2. This is Oxygen. This band here is water. There's little dips. Here is methane. So you can see from a distance with the right instrument, it's actually possible to detect that that planet, that atmosphere has life on it. Now, of course, that's easy on the moon. Now, try to imagine being a bit more further away. So this is a picture of the earth as seen from by the Galileo spacecraft in 1990 on its way to Jupiter.
Galileo was it was to study Jupiter. And this man, Carl Sagan, propose a very interesting experiment. So let's point all our instruments toward the earth while we're there. And we're going to. Analyse the data as this. This was a data from an exoplanet and let's see what are we can actually identify life. So it's basically a control experiment. Can we actually detect life from afar using our instruments? So it made it to a nature paper back in 1990.
And lo and behold, Carl Sagan demonstrated that there was lots of oxygen in a spectrum. We can can see it here. We can even detect pigment from that chlorophyll, which is very exciting. And we can also detect methane in a very unnatural abundance, which it can only explain if there's active biological activity. And there's even even suggestions there's the radio signal to receive on this planet suggests that there may be intelligent life on the planet.
So this is a controlled experiment that, again, from afar you can actually detect life from exoplanets. Okay. But of course, it's much harder than this. So Voyager one in 1990, as it was leaving, it was leaving the solar system well beyond the orbit of Neptune. Took that picture. That's the Earth. And it's now called the Pale Blue Dot. So this is the challenge. So you have to take that life and analyse it and and determine that this planet has an atmosphere and that it has oxygen, methane water.
So that's our goal. But that planet that that picture was taken, only one six thousands from that, the closest star. So you can see this is difficult. But I hope I will convince you that quite soon we'll have the technology to to do that, that task. Okay. So how are we going to do this? Well, we need ways of first detecting planets and characterising this atmosphere. So I'm showing here you hear a picture of the sky, which you can probably look nice, but that's actually the the the great square.
I guess this I'm showing you that region here because there's three stars in that in that region that you can see with binoculars that really made history and have an excellent research. So I'll walk you through all these these stars. So the first one is 51 Pegasi. So that's the first planet around which we discovered a planet around a normal star. So the way it was done, so this what we call the wobbling technique of it's basically literally watching stars dancing.
So basically, you know, we always think that the planet revolves around the star, but really the star also revolved around the planet. In fact, they do revolve around the common point, a centre of mass. As a result, because of the the period of the planet, the star is moving. And so you can actually measure that by taking a spectrum, again, of the of of the star. And while the the the the star moving away from you, the spectrum is blue shifted away redshifted.
So it's very simple. And now we have instrument that can actually do this with very high accuracy. So those are the data. So basically the plan is you go with your telescope, you're in Studio Spectrograph, you take a spectrum and you had it lost, and then you plot it in time and you can see that with time it will oscillate. That's that, the telltale signature of a planet.
Now, just to give you an idea of the difficulty on this, so this the first one was an average of 50 metres per second, but now we can actually detect planets with as low as one metre per second. I'm walking here at the speed of about less than four or five metres per second. Okay, so one very famous discovery that was done back in June of 2012 by the Swiss team, which arguably one of the best in the world to do this kind of work is what we detect a nought mass planet around Alpha Centauri.
B So Alpha Centauri is the closest star system to us. It's actually three stars. It's two stars. It's a binary system component A and B and the Swiss found an earth like planet around component B, so it's about an Earth size, not in the middle of a zone. But yeah, that was quite, quite a groundbreaking discovery. They had found it a rocky planet. Now, it turns out four years ago and I have to say that the actual signal is is marginal. So what you see here. Yeah. Just physicist in the room.
Right. So every point is a radial velocity. Now the scale is change from before this is metres per second. And you think the average of all these points you get the record. So yeah, it was convincing enough to the community to say, yeah, it looks like we've detected a rocky planet around Alpha Centauri B until a team of astronomers, in fact Susan and Ryan here at Oxford realised that data do in fact show that it was not. It was actually stellar activity. The issue is that a star has spots.
As the star rotates, it can fool you that the star is moving, but it's not. It's just bubbling on the surface. So that is very important. And in fact, I'm showing this because, you know, even though you need a very powerful instrument to do this kind of work to detect them, you really need very, very important data analysis tool. And that was one that is very powerful and one that will continue to be absolutely crucial in our quest to detect a biosignature.
Okay. So people do not give up. So around this pair of stars, there's a third one that we call Proxima B. This one is a much fainter star. You cannot see it with your eyes. You need a small telescope. It's a red dwarf and Orion it. There is a planet that was detected to rate of lusty. And now you can see the signal. It's much better behave. But I still put a question mark and that one is right smack into the habitable zone. So then there we go. We have we have one. This one is around.
This is the closest habitable that will ever find. Right. Okay. So we'll see with time whether this planet turned out to be to be true. But I have to say that the signal is much stronger. We'll see. Now moving on to another star, HD 29458b. So this one is very is very similar to 51 figures. And I do not make sure that the the that the planet around 51 because it's a hot Jupiter. It's a planet, the mass of Jupiter, but much closer.
It revolves around this star in three days instead of 12 years, go for Jupiter. So that's why we know that they're very close to their star. They're very hot. So that's why we call them measure hard to believe. So 29458. Was also discovered as a hot to return to the wobbling technique. But that one is very special. The the orbit happens to be aligned with you. So that's when this planet go in front of this star.
It is a small eclipse and you can actually detect that. In fact, it's correcting the easy. And this was done by Didier Tamano and back in 19 into Tarzan. And so basically with the stars winking at you. So the bigger the planet is, the bigger the wink. So this is a very powerful technique because we actually know quite well the radius of stars. So we can measure that depth and you can do that especially in space.
You can measure the radius of the other planet, which is a very fundamental continent. And you want to know, are we dealing with a rocky planet, a small earth sized planet, or a big giant planet? Okay. So that was the trigger to actually of a new mission called Kepler, which was launched in the late 2000. And Kepler has a small telescope that look at this piece of this patch of the sky, which is not much bigger than your hand projected on the sky.
And the vast majority of the close 2 to 4000 exoplanet that we've found so far are from Kepler. So Kepler, the goal couple was to find Rocky Planet around Sun Like Star, just stars like our own. It did find many of them. The problem is that most of these planetary systems are relatively away from us, so it's very difficult even to measure the mass of these planets. Okay. So what did Kepler found?
So this is a picture of our family portrait. This is the gas giant planets Jupiter, Saturn, Uranus, Neptune. The rocky planets are very small on the earth. Venus, Mars, Mercury. And I think this is Pluto here. So what they will point out, do you think Kepler found why? It was a big surprise. It found something like this. We don't know how to call them because they don't exist in our solar system. So we call that either super earth, meaning Neptune's.
We don't know what they are. We don't know what they are. In fact, we're going to learn a lot about those in the coming years. And some of them could be water well, rocky planets covered in oceans. And those things are theoretically possible, but we haven't found any evidence of that yet. But that's a very important discovery. Do to remember that the the most typical exoplanet in a solar neighbourhood does not exist in our solar system.
Okay. Now, even more powerful technique relative to the transit method. Now imagine that while the star of the planet grows in front of a star, you take a spectrum, so you measure its character. This is symbolised by various wavelengths. And so if there's a molecule in the atmosphere that happens to block life like water, the planet will look bigger.
So by measuring the the relative that of these at various wavelength of various colour, you can actually have some insight about the chemical composition of the atmosphere. Now, I have to say this is very difficult to do. We can do it right now. We can do it especially with the Hubble Space Telescope. So here's an actual measurement of the this this this, this contributors to a945 HD. So this is the transit, the depth and the the the black points are the actual.
Data obtained with Hubble and the include this is the model of water. So we have detected water in the atmosphere of an exoplanet. But this is a hot Jupiter. It's not a rocky planet. And doing that for a small planet, it's much, much more difficult. But as you can see, as you will see later, it becomes it will it will be the next few years. Okay. Now, moving on to my favourite star, H.R. seven, 99. So this is the start around, which we actually found the very first image.
So as I said, after 1995, I became very interested in trying to find means techniques, how to actually take pictures of those. So this is illustrated here, how we do this. We basically masked the star. And by doing so, the actually the planet is very faint. Next to it becomes revealed. Now, historically, it wasn't done quite like this. So but we you needed to the biggest telescope. Yeah. You could have in hand and telescope and the best instrument to make your image very, very sharp.
So an actual image of a star on an individual telescope looks like this. Once you remove the actual main signal from the star, it's a it's a complete mess. Okay. So to detect a planet around that mass is very difficult.
And this is where two of my students actually got involved in developing new techniques, new observing strategies with these telescope and data analysis tools to to process the data to turn them into this so suddenly that without, you know, changing any instruments, just new data analysis tools, new tricks, we are able to to to detect very, very faint companion.
Now, we got excited many, many times, but it turns out that the vast majority of those are background stars that happens to be that they're not exoplanets. So it took about ten years to do to do this. And finally, we got lucky. We found that this system this was led by two some our my first student. So we we reported three planets and a year later we found a fourth one.
So if you're not convinced those are planets. So this is a movie of all the data we've acquired on the system in last ten years. And lo and behold, they're really rotating right in the same direction. It is a genuine planetary system. Now, those, even though it was very difficult, it took ten years of effort to actually do this very easy. The brightness ratio of the planets, the stars, about ten, 20,000.
Now, if you want to detect the earth around the solar type stars from afar, that's a ratio of 10 billion. Now, not quite ready to do this, but we think we know how to do it. Okay. And just to give you an idea how difficult that is. Now you have to take the. Oh, yeah, I want to I want to mention something that is really frustrating. Soon after that discovery, we went back and look in the data archive to find out that each are in its own 99 had been observing in 1998.
So our discovery was in 2008. And so this is what the image was reported. Okay. But that they had developed these fancy data analysis tools apply is algorithm and and they turned to this. It was there. So I get mad when I think about it. Yet all these years we didn't have a the tide that went to to telescope two pages all these efforts finally we got lucky. But it it it was there. It was on the Internet. All we needed was a few seconds worth on the laptop to release that up and it was there.
So again, I want to emphasise one very important point. When you think you have the most powerful facility in the world, the largest telescope, the best instrument to make a groundbreaking discovery. Ask yourself, do I have do I have the right analysis? Do you know this is absolutely fundamental. Okay. Now, so this is a new discovery that was done with the Dewey Tunnel in New Jersey. That discovery triggered the even more powerful instrument.
So this is another planet. You can barely see it here. But this time, not only do we have an energy, we have a spectrum and height. And you can see that as we go along the spectrum and that that absorption here is due to methane. So these images really do show that these planets have methane. And I'm showing this just to show that the imaging technique allows you to probe the atmosphere of the planet.
And this is a very powerful technique indeed. And maybe the way one day we will find a biosignature. But again, I won't just show you the difficulty of doing this by showing you one of the deepest image ever obtained with the Hubble Space Telescope. These are galaxies. There's no stars there, but just like the faintest galaxy in there. Okay. And that's a signal of an earth around a solar type star at about ten light years away. The only problem is that that planet is around a very bright star.
You cannot see it. This is very, very difficult. Okay. So what's the road map to find life? Well, the very first things that we need to find more this when you find the closest habitable zone, the closest planets, we need to measure their radius, their mass. Because we want to find out if you have to reduce the volume, if you have the mass, then you know the density. So you know that you're living with a rocky planet. I guess that's absolutely fundamental.
And as I said, you want to focus on the ones that are in the habitable zone to maximise the chance of detecting life. And finally, which is the most difficult part, you want to probe the atmosphere either with imaging or transit spectroscopy, with two techniques that we have in hand to do to do this. Okay. Our best shot in the near term is to focus on these very faint stars, these red dwarfs. Why? Well, because those are the most common stars in the sun.
And what do you think of all you around the sun and you count all the stars? 80% are these red dwarfs, typically a quarter or a fifth of the radius of the sun. And they are very, very faint. And they they are very bright, mostly active fed wavelength and driven by a special aspect. Is that because the star is very faint, the regions where it's habitable, it's much closer.
It's actually well within the orbit of Mercury. In fact, a year on the planet around them, dwarf takes about two or three weeks. Okay. And. And, yeah, so basically much easier. And in general, detecting a planet, detecting its atmosphere around a planet, around a red dwarf is just easier because the planet is much fainter and smaller. Okay. I just want to show you a very famous system. This is the the Trappist system that was discovered a few years ago.
The the star. And this is hard to scale here. So this is a red dwarf. And around this set of the planet, all they all have about the size of the earth and their transit. They're under their stars. And three of them are very close, in fact, is right in the habitable zone. So those that are really real candidates to actually study in detail. And in fact, we will study them later with the James Webb Space Telescope. I'll come back to this. Okay. So what's coming up?
You may have seen the launch of this test scope last week, a very small telescope, which is basically the successor of the Kepler mission. So that's mission is to find very close nearby planets through the transit method. And it will do so by a full camera that can take a picture of, you know, from above 90 degrees. It will tell the sky to buy for 27 days and then move to the next one. So we'll take about one year to do the sun in the sky and then another year to do it the northern sky.
So this is thousands of these you'll find out that the system will find and about a dozen rocky planets right in the zone. So those are the pearl in the sky to study for future calculation. Okay. So and it's not it's not enough if we measure if we'll have the radius of these stars, but we need the mass. As I said, we really need to determine whether they have you know, they are these are rocky or dangerous.
So these are the names of the instruments currently under development in the world to do this. So there's a lot of effort and many of them actually to look at these Red Dwarf. And I live all in two of those instruments and I want all to very briefly spew and arbs. So basically these are machine to use the wobbling technique to measure the mass of nearby exoplanet. So one is on the kind of fronts that we telescope. Yes. It's actually operational.
We're just getting the first light. And one is on the 2.6 metre telescope and on the cap. And we'll have lots of observing time. More than 100 more than 100,000, like of going to have some in time in the next five, six years to to measure the mass of this planet that Tess will find, but also to actually find the closest other worlds. So here's a movie showing you the current census of planets in the solar nebula.
Now, this is a depressing sight because it's far like this kind of this than unit just one fly by three, and you have just like the night years. So every point here is a planet that has been discovered in blue. This is a planet that is in you have a was on. So you see Proxima B is right here. So this is the current census. So over two years it will take about five years. We will interrogate every star in the sky on the close red dwarf and ask, Do you have a planet and is it small?
So this is what we expect to find about 100 planets around that, the close to the sun and about a dozen very close to the. I'm in the habitable zone. Okay. Now moving on to the James Webb Space Telescope. I used to write for 2018, 2019, and now this is 2020. So Tess is about the size of a washing machine. And so you can see the it's mirror, it's much smaller. And this is a gigantic telescope, a collaboration between Nassau County and Space Agency and the British Space Agency.
So this telescope will revolutionise astronomy in all fields and including exoplanet. So I'll just going to give you another know what this telescope will do. So this is the actual telescope. It's not a cat drawing. It's a real telescope built. The instrument that I doing for Canada was delivered July 21st, 2012. So it takes a long time to actually build is a big, big telescope. One important feature of this telescope is the SUNSHIELD, which is about the size of a tennis court.
And all of this is folded into the rocket of a I inside rocket. I'll show you at the end of my talk me a very scary movie, which is the the deployment sequence of this telescope. Okay. So there's four science instruments and all have the capability to actually study the atmosphere of exoplanets. As I said, this is the key to one. They find a biosignature. So I'm responsible for this one. It's called nearest million to know what it means.
But it's a camera with some very specialised models to actually study atmosphere. So I show you that that picture. So three of those played out will be studied by my instrument probably towards the end of 2020. And I will just show you an actual simulations of what we should expect from that for the planet. So this is done by my colleague, John Bennett. You know, this is my are. So this this is actually a data that will show and it's not going to be images.
These are spectra. So what you see in blue, this is the the model of an atmosphere that will be rich in water. Let's suppose that this artist's view is correct, that Trappist one F is a Waterworld. It's got lots of water. So we should expect water in it in its atmosphere. And if that's the case, then we should measure the the blue signal. So in black, those are the data points that the newest instrument will will give us in about 10 hours of observations.
So in only 10 hours of observation with this powerful telescope, we'll be able to tell whether there's water in that in the atmosphere on this planet. Okay. But I have to say that this is probably a very optimistic simulations. You can imagine all kinds of scenarios whereby water would be trapped and then you would not see it. And so this is a I'll show you another simulation to to ask the question. Is it possible that Webb will one day detect about nature?
I'll answer by a big, big maybe. So the reason is that this is probably a more realistic simulation spectra that that well will will give us. And the and so you see various features here, CO2 and the water features only a few parts per million. This is very difficult. The best sensitivity that we can do nowadays with the Hubble Space Telescope is about 1020 BPM. So we need to improve our sense D by about a factor of ten. And but there's one feature it's very interesting, which is this one here.
This is ozone around nine micron and the MIRA instrument built by Europe could actually detect us and that we all understand the performance of this instrument and the telescope to make simulations of how long it would take to do this. So here's an example of a of a planet NHS 1140 B, which is a rocky planet. Right. And you have ozone that was discovered by then it Charbonneau. So we do have targets to look out.
And this is the actual simulated data that we will observe after observing that the planet that by 15 times 15 tens of events and the the ozone feature is is shown here. But the reality is that the stars are always visible. And so it would take actually four years of clock time. So a very significant fraction of Web time to do it. But you can bet that we will look at this star very, very intensely with the James Webb Space Telescope.
Okay. Now, I just want to move on to the future. So this is an animation of a very powerful disco that is currently under development in Europe, the European extremely large telescope, a 40 metre telescope, which will have a lot of chemical data to study exoplanets. And there's others I'm involved in kind of the 30 metre telescope. I'm showing this one because it will likely be the first one, probably a good five years head start compared to other big giant facility in the world.
And but the e-elt remains on the major. A very powerful scientific opportunity for. For Europe to study not only exoplanets, but also the early universe and much further along into the future. Yes, there is a flagship mission that we want and deserve. So this one is a 12 metre telescope. The web is a 6.5 metre telescope, so it looks very similar. And so this would be launched in maybe 2040 ish.
And that that that telescope would be designed to actually paint a picture of an earth so this one would look like this. And this maybe this could be the very first base in Asia. I put a question mark because I'm sure the first time we we claim that it will be very controversial because I won't have time to go into the details. But you can imagine false positives that will generate that signal. And so this will be highly debated. Okay.
I want to finish this by just mentioning that probably the most important part of all this is, yes, of course, these big facilities that cost billions of dollars. But the people so these are the faces of my team at the memorial. And there just are just one team among many others in the world that are all focussed on to one common goal, which is do exploring new worlds and searching for life.
And on this I will thank you and mention my funding agency and our generous donors that may just decide this role that just where possible. Thanks very much.