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Episode 5 (Special Edition): Event Horizon Telescope – First Results

with Dr Roger Deane and Dr Rhodri Evans

On 10 April 2019 six simultaneous press conferences around the world broadcast the first results from the Event Horizon Telescope – a project that was designed to take the first-ever image of a black hole.

We were fortunate to speak with two scientists involved with the project Dr Rhodri Evans a senior lecturer in physics & astrophysics at the University of Namibia, and Dr Roger Deane, Associate Professor of Physics at the University of Pretoria.

Roger spoke to us via Skype from Brussels where he was for the announcement and explained the exciting result and Africa’s involvement in the project.

Rhodri spoke with us before the announcement at the recent Astronomy in Africa conference about plans to build a telescope in Namibia to join the EHT Network.

The EHT Array
This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. This thin disc of rotating material consists of the leftovers of a Sun-like star which was ripped apart by the tidal forces of the black hole. Shocks in the colliding debris as well as heat generated in accretion led to a burst of light, resembling a supernova explosion.
Simulated Image from INTERSTELLAR, from Paramount Pictures and Warner Brothers Pictures, in association with Legendary Pictures.

Episode Links:
Press Release:
https://www.up.ac.za/news/post_2802251-astronomers-capture-first-image-of-a-black-hole
https://www.up.ac.za/news/post_2802266-university-of-pretoria-astrophysicist-part-of-team-involved-in-capturing-first-black-hole-image-
EHT: https://eventhorizontelescope.org

This week’s guests:

  • Prof Roger Deane
  • Dr Rhodri Evans

Acknowledgements

Transcript by Mohammed Riaz and Vuyolwethy Mpetshwa.

Transcript

005 The Cosmic Savannah – Event Horizon Telescope – First Results

Dan: [00:00:00] Welcome to The Cosmic Savannah with Dr. Daniel Cunnama

Jacinta: [00:00:08]  and Dr Jacinta Delhaize. In each episode, we’ll be giving you a behind the scenes look at world-class astronomy and astrophysics happening under African skies.

Dan: [00:00:16] Let us introduce you to the people involved, the technology we use, the exciting work we do, and the fascinating discoveries we make.

Jacinta: [00:00:25] Sit back and relax as we take you on a safari through the skies.

Dan: [00:00:28] Right.

So today we have a very exciting special episode.

Jacinta: [00:00:37] Welcome to our bonus episode

Dan: [00:00:40] Because, just this week on the 10th of April 2019 astronomers released the first-ever image of a black hole.

Jacinta: [00:00:51] Can we just say that again?

Dan: [00:00:53] Astronomers released the first-ever image of a black hole, but wait, what ?

We’ll try and break it down for you. So today we  have two special guests who will be talking to us a little bit about the Event Horizon Telescope and black holes and what this discovery means. And what was our involvement as South Africans?

Jacinta: [00:01:18] Yeah, that’s right. So I guess  the first place to start is to talk about the telescope that did all of this.

It’s called the Event Horizon Telescope or E H T and understand what the EHT is. We first have to talk about another acronym. V L B I, which stands for Very Long Baseline Interferometry. And what that means is it’s like a normal radio telescope or radio interferometer where you have several different antenna, different dishes, and you connect the signal together. And to give you an idea of how big that is, a couple of comparisons I’ve seen in the news and on Twitter recently if you were in Paris, you would be able to read the print on a newspaper in New York. And there was another one too. If you were in Brussels, you’d be able to see a mustard seed in Washington, DC.

Dan: [00:02:41] Yeah. So this very long baseline interferometry combines these telescopes around the world. And in this particular case, the Event Horizon telescope has combined the eight telescopes ranging from Hawaii to South America, Spain, and numerous other locations operate as a single telescope with an aperture of the size of the Earth.

And by doing that, we can get this resolution that Jacinta was talking about. And what that means is that if we look in a very particular wavelength, and that’s what we’ve done here in about a millimetre-wavelength we can actually observe the light around a black hole.

Jacinta: [00:03:26] And this has never been done before, right?

Dan: [00:03:29] No. So  the technology required to do this, obviously firstly you need the individual telescopes to exist and to operate. Then you need to form this  consortium and form a plan and organize these operations so that everybody can do an observation at the exact same time. Then you have to choose your target, try and observe it. Hope the weather’s good at eight different locations around the world. And then take an observation, do a very large amount of data reduction and hope that what comes out of it is what you kind of expect when you, when you model the light around a black hole.

Jacinta: [00:04:08] Yeah. And the data was far too much to send via the internet, so it actually had to go onto enormous hard disks and physically taken to the processing centers, I think it was Boston and Bonn.

Dan: [00:04:21] Yeah. So, shoving hard drives around in airplanes with this incredibly interesting data. Yeah. So the observation in particular that we’re talking about now, this black hole at the center of M87 is a Galaxy fairly near to us, 55 million light-years away. So in our Galactic neighborhood, and the black hole sitting at the center is six and a half billion times the mass of our Sun. So it’s a very, very big black hole.

Jacinta: [00:04:55]  6.5?

Dan: [00:04:56]  6.5 billion.

Jacinta: [00:04:59] Pretty big,

Dan: [00:04:59] And it’s a thousand times bigger than the black hole at the center of our Galaxy, the Milky Way, which is also pretty big. So it’s a very big black hole. And that was why it was one of the targets, right? It was fairly nearby, a very, very big black hole.

So we would expect a fairly large, relatively large angle in the sky. And yeah, the astronomers with the EHT basically combined forces to make this observation and release this image.

Jacinta: [00:05:33]  Yeah. And I guess so if you’ve heard our previous episode, episode four, we spoke to a few radio astronomers about looking at galaxies that have supermassive black holes in them, and what kind of intense energy processes can be  released as a result of this.

Now, these supermassive black holes are not doing something as intense as that but there is stuff orbiting them. Gas and dust orbiting close to this black hole, creating a plasma heating up to enormous temperatures and glowing basically. 

Dan: [00:06:12] Yeah. And then the light that comes off this accretion disk, so it’s a disc of material, which is slowly falling into the black hole.

The light that comes off, gets bent quite violently by the mass of that black hole. So space and time is heavily distorted by something of this mass, which means that the light behaves in, very predictable with relativity, but quite weird ways. And that’s what we essentially have observed now is how this light has bent around this black hole and being beamed towards us in this very neat little ring showing us the matter residing around this black hole. In a very  distant galaxy.

Jacinta: [00:07:01] Yeah, and I mean, I’m sure by now you’ve probably seen a picture of it. It’s splashed all over the news, but if you haven’t, it will be on our website. You can have a look at that picture and I think it looks like the eye of Sauron.

Dan: [00:07:13] Yeah, there’s been a lot of social media attention around.

A lot of memes and things popping up.

Jacinta: [00:07:21] I’ve really been enjoying them.

Dan: [00:07:24] But to give us more of an idea of what went into this observation we’re now joined via Skype from Brussels by Dr. Roger Deane who is an Associate Professor at the University of Pretoria in South Africa, and his team was involved in some of the background work of this observation.

Jacinta: [00:07:48] Yeah, we’ll just warn our listeners that this conversation was via Skype because Roger is in Brussels for the big press conference and to make the announcement. So the quality of the recording isn’t super high, but we know our listerners are all very intelligent,  switched on people, and I’m sure you’ll all be able to fill in the blank words when it cuts out.

Dan: [00:08:11]  It’s a nice little game for you.

Jacinta: [00:08:12] Yep.

 Hello can you hear us?

Roger: [00:08:21]  I can’t actually, I’m in Brussels so I hope this works out.

Jacinta: [00:08:24]  What are you doing in, in Brussels, Roger?

Roger: [00:08:32] So I was really lucky to come to the announcement of the events, the first imaging results of the Event Horizon Telescope yesterday for the world to see. So I went to the European Commission where one of six press conferences was held. And announced the first image of a black hole.

Dan: [00:08:56] Yeah. It was very exciting we were following on social media and following the press conference live, and I think there was a lot of excitement both in the scientific  community as well as the public from this. I think everybody’s social media feeds are all full of images of this supermassive black hole.

Can we start with what exactly is the telescope.

Roger: [00:09:22] Sure. So the Event Horizon Telescope is what we call a very long baseline interferometer. That’s a mouthful. So I’ll break it down. What we do is we have radio antennas spread on continental and indeed planet-sized distances apart from one another.

And then we bring those signals together and combine them with very, very high precision. So the EHT is a VLBI array it uses that same technique of synthesizing an Earth-sized telescope, but it’s special from other Earth-sized, other VLBI. So the wavelength of light that it observes, if you looked at two consecutive peaks, the distance between those two peaks would be one millimeter, In order to do this, it has antennas on very, very high and dry sites. They need to be up on 5,000-meter volcanoes in  Hawaii, down at the South Pole where it’s very, very dry. And the reason for that is the atmosphere basically absorbs these frequencies.

Jacinta: [00:10:20]  That’s great. And what did we actually detect? What did we look at with the EHT?

Roger: [00:10:25] Well to summarize a ring of fire, in the great words of Johnny Cash. But the image that was made, was a complete ring, which is basically what we call the shadow of the black hole. Now what we were seeing is light in the immediate vicinity of that boundary layer, which defines the point of no return.

When you enter the black hole and exit our Universe, there is a sharp feature at this boundary point. So there is a point at which light disappears from the Universe if you will or at least from our view of it and that which does come to our telescope and eyes. And that is a sharp feature known as the black hole shadow.

Jacinta: [00:11:09]  Which black hole did we look at?

Roger: [00:11:11]  So on cosmic scales, this is a fairly nearby giant, or we call it elliptical, about 55 million light-years  away. And essentially the center of this  gargantuan galaxy lies a very, very massive black hole, 6.5 billion times the mass of our Sun. And that was the image that we had unveiled yesterday.

Dan: [00:11:33] So Roger, why this galaxy, I mean, I think most people would expect that we would try and go for the supermassive black hole at the center of our own Galaxy, the Milky Way. Why was this the first one?

Roger: [00:11:41] Yeah, that’s a really good question. Why those two targets are best candidates and our primary targets as the EHT consortium. The shadow size that I’m describing, that sharp feature the ring of fire, scales with the mass of the black hole, but obviously the more distant the black hole, the smaller it appears, and the distance.

 Those two targets, we’d have the largest apparent size of the shadow on the sky. So that’s why those are the two priorities. So both of these are predicted to have a shadow size about the same size. They are very  different black holes though, they are a thousand times. So, the more nearby Milky Way black hole is about a thousand times closer than M87. Now there’s a bit of a complication to the observations of the black hole at the center of our galaxy in that it’s a thousand times less massive than the black hole M87 that we revealed yesterday. So that means it’s a thousand times faster.

And by that, essentially there is variability of the emission. A change on the timescales of minutes. That presents a challenge to our calibration techniques. So it was a lot easier, for that reason. And then a second reason is that we lie in that thin disc, and in that disc, is a lot of free electrons, which actually distort our view, even at these high frequencies.

That process could actually erase the signature as well. So it’s a much faster black hole, if you will, at the center of our Galaxy.  And we have this added complication of living in the Galaxy, which, makes it a harder target. But we’ve set our sights on that and data processing is happening as we speak.

Dan: [00:13:33] So last year with the MeerKAT telescope, we observed the center of our Milky Way, and that was a slightly different wavelength. How is this different? And I mean, how are those related?

Roger: [00:13:48] Yeah, well, also a great question. So, the beautiful image that was unveiled by MeerKAT at the inauguration last year basically shows very energetic phenomena in the Galactic center, in that region.

The EHT observes that wavelength of light, as I said, that is one millimeter apart, between two consecutive peaks, which is about a factor of a hundred smaller than the MeerKAT image that you saw last year. So it is essentially one of the pixels right at the center of that image. But there’s another factor at play. Even if you have the sharpness of view to see the actual hot plasma that lies at  the center of our Galaxy, would be opaque to MeerKat. So you really have to go to these high frequencies to be able to actually peer through the gas  to be able to see this.

Dan: [00:14:37] So in terms of coordinating between eight telescopes across many continents around the world how do you guys arrange for such an observation?

I mean, do you have to wait for a particular date and time?

Roger: [00:14:52] Yeah, it’s a really interesting mode of operation. So firstly, you have to coordinate that you get a block booking, if you will, of all these independent observatories, which includes something like ALMA which is of the most valued time in the millimeter astronomy.

And the way it works is basically every year’s campaign gets five nights in observing, but it’s awarded in a two-week window. And because we’re so critically dependent on good weather on most of the sites, we have an EHT team at every single one of these sites, including the South Pole.  And there is a go, no go decision at the start of every new day, based on where the predictions that we have from purpose built software that we use, which incidentally actually goes into our simulations for later on.

So it’s five nights carefully coordinated, but only decided on the day in a two week period around March, late March, early April of every year.

Dan: [00:15:55] So we’re going to have to wait for another year before another attempt can be made. So say at the Sagittarius-A *?

Roger: [00:16:04] Well, not quite, because we have data in the can. Okay. Because the Event Horizon Telescope consortium had to basically create new techniques for A: the actual calibration imaging and B: the analysis because it’s all-new. It’s been a a feverish period of activity within the consortium to get this all right, but things will become a bit easier now  that all this work’s been done.

And data will come, results will be announced more frequently, but essentially we still have 2017 data from Sagittarius-A *. Yesterday’s results on M87 were from the 2017 run as well. We then have 2018 data on both those targets as well. So you might not have to wait as long as a year.

Dan: [00:16:57] Wonderful.

Jacinta: [00:16:57] What was your involvement in this discovery and you and your team and at the University of Pretoria?

Roger: [00:17:06] Right. So  the University of Pretoria’s his role was to create a highly realistic simulation of this Earth-sized array. We did this because we want to understand its limits. We want to understand the extent to which we can actually infer the presence of black hole shadows in the data. This folds in all the complexities and imperfections and corruptions that  might come from the engineering of the instrument, the synchronization of the different data streams, and of course the weather that’s present above each site, which can erase the signature of the black hole shadow entirely.

Dan: [00:17:55] So just to explain to the listeners that this simulation, you’re basically putting in test information for all of these situations and then seeing how the telescopes should respond given those conditions.

Roger: [00:18:10] Yes,  because  a radio interferometer, that this instrument where, you know, we combine the signals from independent antennas, just like the way that MeerKAT works is, you know, it’s not a point and shoot digital camera.

There is quite a complex process of combining, converting voltages into actual images. Especially, so when you’ve got antenna spread across the earth that exacerbates the problem quite a bit. But essentially we can make a prediction of what the shadow might look like  and then pass it through in a way that it would mimic the real data.

And we can understand the effects of the photons hitting the antenna through to the final data analysis. We can understand how instrumental imperfections and whether they are actually impacting those signals.

Dan: [00:19:07] So there a lot of excitement and, and talk when the movie Interstellar came out about that simulation of what we should see, what black holes would look like.

And, that was at the time touted to be one of the most accurate simulations. That information. I mean, is that useful to you? Are you using those sorts of simulations to feed into your things.

Roger: [00:19:35] No, the black hole sorry, the Event Horizon Telescope consortium has developed I think was definitely the largest suite of black hole simulations.

That’s not my part of the work that is, you know, theory and, and general relativity. People who were looking very carefully and figuring out how light  behaves in different space-times and how the thermodynamics of the gas behaves. But the Event Horizon Telescope developed its own  huge suite of these perhaps not as quite high resolution as the single black hole in Interstellar.

But the purpose here was to actually understand the physics and what you might remember was that in the Interstellar black hole, Christopher Nolan decided that there was a certain observational characteristic of the black hole shadow that might be too much for the public to grasp.

And that was the fact that the light travels obviously, quite close to the speed of light in the immediate vicinity in the shadow. So on one side of the shadow, it’s actually brightened. And on the other shadow, it’s slightly dimmed. Christopher Nolan removed that aspect of the simulation. He made an executive decision, but in the real image that was unveiled yesterday, you can actually see a difference in the brightness of the  ring on one side versus the other. If you have the image in front of you, you’ll see the bottom. It’s a lot brighter compared to the top. And that is reflective, we have argued, of this gas that is orbiting the black hole at very high velocity, quite close to the speed of light or at least  comparable to the speed of light.

And therefore there is this dimming and brightening effect.

Dan: [00:21:28] So basically the black hole and all of the matter around it is spinning very, very rapidly on the sort of top to bottom axis as we look at the picture.

Roger: [00:21:40] Well, we know that the plasma is spinning fairly rapidly. We don’t know for sure about the spin of the black hole, but we could put some constraints on the spin of the black hole. To first order, the dominant effect is actually the mass of the black hole. About a 10% effect is the spin of the black hole. So as we improve the image, we’ll be able to make better constraints on how fast the hole is actually spinning, but we can use independent information on that spin. We think this is a fairly highly  spinning black hole, which is consistent with expectations.

Jacinta: [00:22:17] Well thanks very much for speaking with us, Roger. We’ll let you go cause we know you’re extremely busy and everyone’s trying to clamor for an interview with you. So enjoy Brussels and thanks again.

Dan: [00:22:27] Yeah, hope you get some rest and also a bit of a celebration.

Roger: [00:22:30] Thanks very much guys. Great to talk to you and love your work. Keep going on.

Jacinta: [00:22:41] Okay. So that was really exciting. I’m really glad Roger managed to find some time to talk with us. He’s been extremely busy, as you can probably imagine. Yeah, I guess so much of that was really exciting. I really liked also hearing about Interstellar and the simulations and how it’s related to black holes and the work that they’re doing.

I think it’s a cool little fact that the simulations in the Interstellar were made by a real astrophysicist Kip Thorne and in his research team, and Kip Thorne later went on to win the Nobel prize in physics in 2017 on something different the discovery of gravitational waves,  but also something else that proves Einstein’s theories.

Dan: [00:23:25] Yeah. So not just any, physicist. Doing these calculations and Nobel Prize winner. So I think we can trust the simulations in Interstellar with some artistic license but taken by Christopher Nolan. So what next for the EHT. It was very exciting to hear Roger say that they have data in the bag for the Sagittarius-A star, which is the black hole at the center of our Milky Way.

Because while it’s a lot smaller than this black hole, we’ve just observed. It’s much nearer. So we may see something quite different move across the sky very quickly. So it’s a completely different challenge to try and observe.

Jacinta: [00:24:13] Yeah, it’s a thousand times smaller, faster, and closer than the black hole M 87. But I’ve heard it also referred to as like taking a picture of a small toddler that’s racing around the house for eight hours. Quite hard to capture.

Dan: [00:24:29] In order to do that the  EHT isn’t gonna be resting on its laurels. They’re in the process of incorporating other telescopes into the network so that they can prove their resolution.

And there are currently plans afoot to build one of these stations on the African continent in Namibia. And fortunately, we recently spoke to Dr. Rodhri Evans who was in Cape Town for the formation of the African Astronomical Society, and he spoke to Jacinta about these plans and, the incorporation of a telescope in Namibia into the EHT. In the future.

Jacinta: [00:25:09] Yeah. I just happened to speak to Rhodri a couple of weeks ago, and this was, of course before the announcement, but it was well-timed. We didn’t yet know what was about to be announced. But I think it’s super relevant because if we can get this telescope in Namibia, then that’s going to dramatically improve the angular resolution of the EHT and maybe give us a better shot at looking at Sagittarius-A star and also exciting that some of the data is already in the bag. You heard it here first folks. Okay, let’s hear from Rodhri.

Hi, we’re chatting to Rhodri Evans who works at the University of Namibia. Welcome Rhodri.

Rodhri: [00:25:57] Thank you very much,

Jacinta: [00:25:58] Can you tell us who you are?

Rodhri: [00:25:59] Yes. My name is Rhodri Evans. I am originally from Wales. I’m a senior lecturer at the University of Namibia based on the  main campus in Windhoek, and prior to moving to Namibia, I was working at Cardiff University, and prior to that, spent nine years working in the United States. So a sort of typical academic, I’ve worked in lots of different places. I’m hoping that maybe it will be my last stop though but, you never know.

Jacinta: [00:26:26] How do you find living in Namibia? What’s it like?

Rodhri: [00:26:30] Well, I couldn’t have picked a country that’s more different from Wales.

It’s a, very dry desert-like climate in Namibia. And that’s actually why the project that I’m working on will be based there. But I find it fascinating because it’s so different to what I’m used to. And one of the other things I like about the country is, there are only 2 million people who live in the country, even though it’s more than three times larger than the U.K which has 65 million people.

So I enjoy the lack of people in the wide-open spaces.

Jacinta: [00:27:01] Right. And now you’re working on something called the AMT, the Africa Millimeter Telescope. Can you tell us more about what that project is?

Rodhri: [00:27:10] Yes correct.  So because Namibia is such a dry country, it’s actually ideal for doing a type of astronomy called millimeter-wave astronomy.

So millimeter-wave astronomy, as the name implies, uses electromagnetic waves, which have a wavelength of, about a millimeter, and that kind of radiation. Gets absorbed by water vapor. So you can only do it in very dry places. So for example, in Europe, it’s only really in Southern Spain that you can do millimeter-wave astronomy and Namibia is the driest country in sub-Saharan Africa.

And we have a mountain called Mt. Gamsberg, which is. I’m about three hours Southwest of the Capital Windhoek, which is at an altitude of just under 2400 meters, which is extremely dry. So the plan is to put this millimeter-wave telescope on Mount Gamsberg, and when it’s there, it’ll be Africa’s first Millimeter Wave Telescope.

So the opportunity to be involved in something that was going to be the first on the continent is what attracted me to do  Namibia.

Jacinta: [00:28:15] That’s really fantastic. I’m really exciting, for Namibia and for Africa. So what will this telescope do?

Rodhri: [00:28:22] Well, the telescope will do lots of things, but the main science that it’s been sold on is to be part of something called the Event Horizon Telescope.

And this is a network of telescopes that are attempting to image the black hole at the center of our Milky Way Galaxy. So we now know that there is a black hole at the center of our Milky Way Galaxy. The evidence is overwhelming, but as some of the listeners may know, you can’t actually see a black hole.

Directly by the very nature that not even light can escape. But what you can do is see the environment around the black hole where the material is falling into the black hole. And the point of sort of no return for a black hole where once the material crosses, it’s, you’ll never see anything from that material is called the Event Horizon.

And if you calculate the size of the Event Horizon for the black hole at the center of our Milky Way Galaxy, it has a, tiny, tiny angle on this guy. It’s 10000000th of an arc second. There are 3600 arc seconds in one degree, and as people know, 360 degrees in a circle. So it’s an absolutely minuscule angle.

Jacinta: [00:29:27] Absolutely tiny.

Rodhri: [00:29:29] The only way that we currently have to observe such a tiny angle is to link up telescopes in different parts of the world, a process which we call very long baseline interferometry. And although that’s been done at radio wavelengths for decades, actually, if you were to use radio wavelengths, the earth isn’t big enough to be able to image such a small angle.

But millimeter waves are at that sweet spot where you can do VLPI, but it’s short enough that the earth is a big enough baseline. So we’ll be joined in part of an already existing network called the Event Horizon Telescope. The other telescopes are in places like Chilie, North America, Hawaii, Greenland, Mexico.

And there is one at the South pole as well. But there’s nothing in Africa and actually having a telescope in Africa will help improve the images that we can obtain with this  network of telescopes. So that’s the plan. To put this telescope, a 15 meter dish on Mount Gamsberg in Namibia.

Jacinta: [00:30:29] Right? So you’re putting a telescope on a flat mountain top in Namibia, and it’s going to be connected with other telescopes all around the world. And the goal of that is to image the Event Horizon of a black hole.

Rodhri: [00:30:43] Exactly. So the imaging campaign which there was one in 2017, for example, another one last year. They happen in March and April because as I mentioned earlier, you need extremely dry conditions to do millimeter-wave astronomy and for example, the dry season in places like the desert southwest of the United States and Mexico is in March, April time of the year. So that’s when the observing campaigns happen.

So we will join that network when our telescope is ready and hopefully in 2021 or 2022. And, as I say, because of the position of our telescope and the fact that it’ll be able to link up and  observe the same object simultaneously with telescopes in the Western hemisphere. We will improve the resolution of the images that the network of telescopes are able to get.

Jacinta: [00:31:37] That’s amazing. So can you tell me more about this project to image the Event Horizon? I’ve heard it described before as imaging the shadow of a black hole. Is that the same project?

Rodhri: [00:31:47] Yes, exactly. So as I mentioned earlier, you can define the event horizon as the point of no return. Once an object crosses that. You won’t see any radiation coming from it. So in effect, we’re observing that the shadow of the black hole, the material that is just outside of the event horizon, that is. Swirling into the black hole. And given the massive, our black hole at the center of the Milky Way Galaxy, which is about 4 million times the mass of our sun.

You can work out just from basic physics, what size that would mean. And then given our distance from the center Milky way you can work out that it would suck down an angle of 10 millions of an arc second, 10 microarc seconds.

Jacinta: [00:32:27] Amazing. So what did we expect it to look like?

Rodhri: [00:32:30] That’s a very good question. Actually my understanding is that the movie Interstellar had a lot of good simulations of what light around a black hole looks like.

Jacinta: [00:32:42] It did, i remeber that movie

Rodhri: [00:32:44] So probably the best thing is for listeners is to rent Interstellar and have a look at the kind of effects a black hole has on light. Basically, we’re expecting to see a sort of curve of light as light is distorted by the gravitational effects of the black hole.

Also, Einstein showed back in the early 19 hundreds that gravity will actually bend light. So the light that we’ll get from the vicinity of the black hole will be highly distorted by the gravitational effects of the black hole, where, of course, the gravitational field is extremely strong, but simulations show that by adding the AMT to the network of telescopes, we will significantly improve the image that we see.

So we’ll be part of a, not quite worldwide network. A sort of Western hemisphere network of telescopes trying  to observe this fascinating object at the center of our galaxy.

Jacinta: [00:33:42] Yeah really amazing. So this is in our galaxy, inside the Milky Way. And you said that there’s some stuff falling into it?

And that’s what we’re trying to see. Are we in any danger from this black hole?

Rodhri: [00:33:54] We’re not in any danger from this black hole. And interestingly, it’s a question I asked my students if we were to replace our sun, by a black hole of the same mass of our sun how would it affect the earth and the answer is they wouldn’t, apart from the fact that we wouldn’t have the heat and the light coming from the sun, our orbit would remain exactly the same.

So you actually have to be very close to a, black hole to be affected by it and to be sucked into it, to sort of use the popular idea. So it’s only material right towards the center of our Milky Way Galaxy, which has been sucked into the black hole. And certainly the orbit our sun is completely unaffected by the fact that it’s a black hole rather than 4 million stellar objects. The mass of the sun is at the center.

Jacinta: [00:34:39] And how did it get to be so  huge? How did I get to be the massive 4 million suns?

Rodhri: [00:34:45] We don’t know the answer to that question. So the evidence that we have a black hole at the central Milky Way galaxy, there was a very compact object, first observed in 1974, and then by the 1980s, a couple of teams, one in the United States at UCLA, University of California Los Angeles, and the other team based in Germany at one of the Max Planck Institutes. They’ve been studying the motions of stars for more than 30 years now. And that’s how we know the central object has this massive, about 4 million times the mass of the sun as, you know, it was pretty well determined by the two teams independently. What we don’t know is how the supermassive black hole formed.

And in the last 15 or so years, the Hubble space telescope has discovered that every galaxy that we look at has a supermassive black hole at its center, not just our Milky Way Galaxy, but every galaxy. And intriguingly, it seems that the ttal massive of a galaxy is related quite closely to the, mass of the central black hole. There’s a correlation between them and that we do not understand either. So it seems that supermassive black holes play a central role in the formation of galaxies, but quite what that role is not something we know the answer to yet, but certainly being able to essentially directly, image the black hole for the first time is an important step in understanding the role of these black holes in our Galaxy’s evolution and hopefully in the evolution of all galaxies.

So that’s an amazing science. Is the AMT going to do any other types of science? Yes. So because the observing campaign of the Event Horizon Telescope is only in March, April. That of course, leaves most of the year when it’s not going to be doing that particular project. So. One of the things that makes the project so interesting to me is that we will have, you know, essentially 10 months of the year when we can do other science with the telescope. So, for example, we’re open to  do a survey of the southern sky at millimeter wavelengths, which really hasn’t been done since the telescope that we’re going to use was decommissioned. So we’re actually gonna use an already existing telescope is called the Swedish ESO sub-millimeter telescope-SEST it went into operation in 1987 and then was decommissioned in 2003.

So really since 2003, there hasn’t been a telescope doing large-scale surveys of the Southern skies. And of course, technology has moved on since then in terms of detector technology receiver technology. So we’re planning to do various observing campaigns, including a large-scale survey of the southern skies. A survey of the Milky Way galaxy. Looking at, in particular the astrochemistry of the Milky Way, the various combinations of different molecules and elements in the Milky Way galaxy, and looking at active galactic nuclei. So these are other signatures of black holes in other galaxies.

When we look at some galaxies, we see that the  nucleus of the galaxies is particularly active, and that’s due to the effects of the central black holes. So we’re planning to observe some of these active galactic nuclei beyond our own Milky Way Galaxy as well. So there are lots of signs that we’ll be able to fill the rest of the year with.

Now. The driest times of the year are June, July, August. So that’s when we’d expect to get the best data. But that doesn’t mean we can’t be making observations at other times. There is just that we will be more limited in the sensitivity at other times of the year because the atmosphere isn’t quite as dry as the May, June, July, August period.

Jacinta: [00:38:24] Great. And you mentioned that the actual telescope that’s going on the top of Mt. Gamsberg is SEST the Swedish ESO millimeter telescope. Now, I think you said that’s currently in Chile.

Rodhri: [00:38:35] Right, so the telescope was put at La Silla in Chile back in 1987. It was operated for some 16 years and then decommissioned in 2003.

So it’s still sitting there and Chile, We will dismantle it, take it down bit by bit, ship it initially actually to France to have some repairs because as it’s been sitting idle for the last 16 years, there are a couple of panels that are slightly rusted, need repairing. But actually very little. You know, we’ve done a thorough test of the telescope and everything is fine apart from just needing to replace a couple of the panels. And then once it’s been repaired in France, we will ship it down to Namibia. And so stopped taking it up the mountain. Now the mountain, as I mentioned earlier, is at an altitude of nearly 2,400 meters, and it sits about 600 meters higher than the surrounding plane.

And the road up to the top of the mountain is extremely precarious. So we’re going to have to improve that road. There’s no way we can take the parts of the telescope up to the top of the mountain without improving the road. So that’s part of the project will be in improving the road, but it’s the top of the mountain, it’s often referred to as Namibia’s table mountain.

It has a completely flat top about  600 meters by maybe 200 meters. So there’s lots of room on the top for other telescopes as well. It’s an almost undeveloped site at the moment, even though way back in the 1960s, the European Southern observatory considered it as, a place to put the telescopes that ultimately went to Chile, and it was reconsidered again in the 90s when ESO was trying to negotiate, I guess, the site for what became the very large telescope, which was put in a different place in Chile.

And maybe as part of the negotiations, they did another site test of Mt. Gamsberg, just to show that Mt. Gamsberg was just as good on all the tests that have been done on how good an observant site Mt. Gamsberg have shown that it’s  just as good as Chile. My hope is beyond the AMT that Mt. Gamsberg, can be gum as another site in the Southern hemisphere for telescopes.

At the moment, there’s nothing on the top, apart from a German amateur telescope, but in 20-30 years’ time, it could be a major observatory like Mauna Kea or, some of the sites in Chile.

Jacinta: [00:41:05] Wow, thats incredible, i mean its great, we recycling this telescope, that it gets a whole new life to do something brand new and you know mother nature has given us this big mountain that’s got  a completly flat top. You showed me a picture of it earlier and its incredibly flat at the top, and we going to use it to look at the supermassive black hole at the center of our Milky Way.

Rodhri: [00:41:21] And Namibia, because of its extremely dry climate and very low population density  has the potential to be one of the major observing places in the world done for various reasons.

It hasn’t developed in the last 30, 40 years to be competing with Chile and Hawaii has as examples. But there’s no reason why that can’t happen in the future. It’s just a question of developing the infrastructure for the mountain on getting the government on our side, for them to see the potential for Namibia of having these telescopes in the country.

You know, rather than looking upon it as a negative thing, which initially, most people do change. Change is always a bit scary to get them to realize that the huge potential, not just in terms of revenue, but in terms of jobs for local people. I was just chatting in the last couple of weeks to someone who graduated in physics from the University of Namibia and she’s currently teaching. And she said, well, outside of teaching, there aren’t any jobs. And then maybe a, which, although it’s not strictly true, is truer than it should be. And by developing these kinds of facilities there will be far more  job opportunities for people trained in STEM subjects than there currently is.

Jacinta: [00:42:34] Wonderful. Well, we’re all wishing you well. We’re all cheering for you in Namibia and for the AMT. Is there anything else you’d like to talk about today?

Rodhri: [00:42:45] Well, just the fact that’s, I’m here for a couple of days in Cape Town. I’m seeing all the different projects that are going on in Africa and astronomy. And it really is quite inspiring because as someone who up until two years ago would only ever worked in Europe and North America is just great for me to see that there is, a lot going on in Africa and astronomy and certainly Africa needs to do a better job of advertising what it’s doing to the rest of the world.

But this meeting and the beginning of the Africa astronomy society. It’s a start of putting Africa on the world map as far as astronomy is concerned, which it certainly has, the potential to be as big a contributor to world astronomy as some of the other better-known continents.

Jacinta: [00:43:32]  And hopefully this podcast will help as well.

Rodhri: [00:43:34]  Yes. Let’s hope so. Yes.

Jacinta: [00:43:36] Thank you very much for speaking with us today. Rhodri

Rodhri: [00:43:38] You’re welcome. Thank you very much.

Jacinta: [00:43:47] Well, it’s been a big 24 hours for all of us at the time of recording.

Dan: [00:43:52] Yeah, it’s been very exciting. These astronomical discoveries seem to happen more and more these days. You know, not a month goes by it feels like when something major for the first time gets announced or released,

Jacinta: [00:44:05] Or at least not a year until something really major.

Dan: [00:44:08] Yeah. It’s very exciting, to live in an exciting time, to be involved in astronomy, and astrophysics. And great to hear how Africa is getting involved in some of these projects. I think that the incorporation of a telescope in Namibia will greatly improve the resolution of this telescope. The EHT, because at the moment there’s nothing on the African continent and it’s a big, empty patch and in terms of the footprint of that telescope.

Jacinta: [00:44:41] Yeah. And as I’m Roger, he said, Namibia is perfect because it’s  really dry and you need a very dry atmosphere in order to do these particular observations. And it also has currently a low population density which makes it, again, perfect for these kinds of observations. So hopefully Mt. Gamsberg. It is.

Dan: [00:44:58] Yeah. And then hopefully we will be involved and, improvements in these observations and maybe future observations of other black holes and other galaxies.

Jacinta: [00:45:09]  Yeah, exactly. I wonder what else we can find, what else we can look at.

Dan: [00:45:12] I mean, that’s the astronomer’s motto, isn’t it? Like, you know, make a big discovery. What else can 

Jacinta: [00:45:17] What next?

Dan: [00:45:19] Absolutely. Well. Yeah, I mean, a very exciting special episode. Thank you very much for joining us and we hope you learned a thing or two.

And please join us again soon.

Jacinta: [00:45:31] As always, you can follow us on Twitter, Facebook, and our website, thecosmicsavannah.com. And that’s where we’ll have links related to today’s episode.

Dan: [00:45:40] Yeah. It’s a special thanks today to Associate Professor Roger Dean for joining us via Skype from Brussels and Dr.Rhodri  Evans.

Jacinta: [00:45:49] Thanks to Mark Allnut for a music production at Janus Brink for the astrophotography and Lana Ceraj for the graphic design used to create the podcast art

Dan: [00:45:57] The Cosmic Savannah was created with the support of the South African National Research Foundation and the South African Astronomical Observatory.

Jacinta: [00:46:05] If you enjoyed this episode, please tell a friend and help us by subscribing on iTunes, Spotify, or wherever you get your podcasts and leaving us a review.

Dan: [00:46:15] And we’ll speak to you next time on The Cosmic Savannah.

Posted on

Episode 4: Black holes and Radio Jets

with Dr Imogen Whittam and Lerato Sebokolodi

Episode 4 features Dr Imogen Whittam, a SARAO Postdoctoral Fellow at the University of the Western Cape and Lerato Sebokolodi a PhD student, based at SARAO and the National Radio Astronomy Observatory (NRAO) in the USA.

Imogen talks about her work on Active Galactic Nuclei (AGN), stemming from the super-massive black holes that reside at the centre of most galaxies and how we learn how these massive beasts work.

Lerato chats about one AGN in particular, the famous Cygnus A and her work on the magnetic fields that drive the formation of the beautiful jets pictured below.

An image taken at radio wavelengths of the dramatic jets of charged particles being ejected from the nucleus of the galaxy Cygnus A. Image credit: NRAO/AU.

Episode Links:
SARAO: https://www.ska.ac.za/about/sarao/
UWC: http://astro.uwc.ac.za/
NRAO: https://public.nrao.edu/
MeerKAT: https://www.ska.ac.za/science-engineering/meerkat/about-meerkat/
JVLA: https://science.nrao.edu/facilities/vla

This week’s guests:

  • Dr Imogen Whittam @imogenwhittam
  • Lerato Sebokolodi



Posted on

Episode 3: SETI with MeerKAT

with Dr Griffin Foster

In this episode Dr Griffin Foster describes the planned hunt for extraterrestrial intelligence with South Africa’s MeerKAT telescope!

Griffin is from the University of Oxford and is the project scientist for Breakthrough Listen – a program to hunt for signs of extraterrestrial intelligence using radio telescopes.

Griffin explains, in a surprisingly down-to-earth and practical way, why we might expect intelligent extraterrestrial lifeforms to exist elsewhere in the Universe, how they might be trying to communicate and how we might search for these signals.

Griffin and the Breakthrough Listen team plan to conduct part of their search with the new MeerKAT radio telescope. MeerKAT is one of the world’s most advanced radio telescopes and is located in the Karoo in South Africa.

Episode Links:

BL@MeerKAT announcement: https://breakthroughinitiatives.org/news/23

Berkeley SETI Research Center: http://seti.berkeley.edu/

This week’s guest:

  • Dr Griffin Foster

Acknowledgements

Transcript by Lynette Delhaize.

Transcript

Jacinta: [00:00:00] Welcome to The Cosmic Savannah with Dr Jacinta Delhaize

Dan: [00:00:07] and Dr. Daniel Cunnama. Each episode we’ll be giving you a behind the scenes look at the world class astronomy and astrophysics happening on the African skies.

Jacinta: [00:00:17] Let us introduce you to the people involved, their technology. We use the exciting work we do and the fascinating discoveries we make.

Dan: [00:00:24] Sit back and relax as we take you on a safari through the skies.

Welcome to today’s episode. Thank you for joining us again. So Jacinta, what do we have in store today?

Jacinta: [00:00:37] Yes. Hello. Today we are talking about aliens, and how we’re using big radio telescopes in South Africa to search for extraterrestrial intelligence .

Dan: [00:00:51] And how exactly are we doing that?

Jacinta: [00:00:53] Well, recently at a conference, I managed to speak with Dr Griffin Foster from the University of Oxford, and he is part of a team called Breakthrough  Listen which will be using the MeeKAT telescope in South Africa to start SETI.

Dan: [00:01:09] SETI being?

Jacinta: [00:01:10] The search for extraterrestrial intelligence.

Dan: [00:01:13] So Jacinta you’re a radio astronomer. Why do we want to use MeerKAT in radio astronomy?

Jacinta: [00:01:18] Yeah, so I guess traditionally astronomy has been done with optical telescopes, and all of us are familiar with optical light. It’s the type of light that we can see with our eyes. But there are many different types of light, and this is called the electromagnetic spectrum. And one of these types of light is  radio waves.

Now it’s a common misconception that radio waves are a type of sound instead of a type of light. And that’s because we all have radios, which we listen to, right? But radio stations transmit their signals as radio waves, which are a type of light which are picked up by your antenna on your radio instrument, which converts the light into sound waves.

And that’s what you can hear. But radio waves are a type of light, and they can come from space as well as being generated here on the Earth.  And the really useful things about radio waves is that they’re very long wavelength, which means that they can travel straight through dust, and there’s a lot of dust up there in space, in galaxies, in the Milky way.

So that blocks our view of much of the Universe. But if we look at this Universe at radio wavelengths,  then we can see straight through the dust and see what’s hiding behind it. And that’s why we want to do radio astronomy.

Dan: [00:02:30] So the Breakthrough Listen project is obviously continuing these misconceptions because they’re actually looking at light.

Jacinta: [00:02:36] True. True. Okay.

Dan: [00:02:38] Good to know. Okay.

So South Africa currently has one of the best radio telescopes in the world. Can you tell us a little bit more about MeerKAT?

Jacinta: [00:02:47] Right. So MeerKAT is a big new radio telescope that’s in the Karoo in South Africa. It was launched in about July, 2018. And it’s currently the world’s most powerful functioning radio telescope.

So a radio telescope kind of looks like a satellite dish. It’s made of these antenna that look like satellite dishes. MeerKAT has 64 of these and they are  spread out over about eight kilometers in the Karoo region. And this forms an array of antennae or an interferometer, we call it. This makes it a very powerful telescope.

 The further you can spread these dishes apart, the better your angular resolution. And this means you can see things that are smaller and of course, things that are further away in space appear smaller to us. So this is helping us to see very distant objects in the Galaxy and in the Universe.

Dan: [00:03:42] And MeerKAT of course, is a precursor telescope to an even larger telescope, which is coming.

Jacinta: [00:03:48] Yeah, that’s right. Even though MeerKAT itself is currently the most powerful radio telescope, it’s only approximately one to 3% the size of a new radio telescope that will be built in the future called the Square Kilometer Array, or SKA for short.

This will also be built partially in the Karoo, and the other part in Western Australia. And this is going to be a really phenomenal scientific instrument, which is probably going to revolutionize our understanding of the universe. But this will be starting to be built soon and will be hopefully functional, the first phase, in about 2025 so we’ve got some time until SKA is up and running to use MeerKAT, which itself is going to produce some really amazing discoveries.

Dan: [00:04:34] I’m looking forward to hearing more about the exciting discoveries MeerKAT is hopefully going to make, and one of those discoveries could be life?

Jacinta: [00:04:42] Could be. Yeah. So there’s this project called Breakthrough Listen, and it’s essentially searching for signals of intelligent alien life elsewhere in the Galaxy using MeerKAT.

Dan: [00:04:56] Sounds fascinating. So are they piggybacking on current observations or are we specifically looking for aliens?

Jacinta: [00:05:02] Right, exactly.

So it’s sort of like a timeshare situation where these telescopes are going to be doing their science observations for other projects. And then Breakthrough Listen can essentially piggyback  onto these. So it just uses the data that’s being taken for these other purposes, and then it can be analyzed in a different way to commensally search for aliens at the same time as doing other science. When I say aliens, of course, what I actually mean is extra terrestrial intelligence. So scientifically speaking, there’s no evidence for this existing yet. That’s why we’re doing a scientific search for this with MeerKAT. What do you think, Dan?

Dan: [00:05:44] I think that there is a high likelihood of there being life elsewhere. If it’s transmitting in the radio and it’s near enough for us to see, I think that’s probably unlikely.

Jacinta: [00:05:59] Yeah. So I spoke to,  as I said before, Dr. Griffin Foster from the University of Oxford recently, at a conference and we had a long discussion about these issues.

How do we reconcile aliens in pop culture with science? What are the chances of actually detecting a signal  from an alien civilization with a telescope like MeerKAT?  How exactly do you do that and what kind of signal do you even look for? So Griffin gave some amazing answers, and I think we can have a listen.

Dan: [00:06:34] Yeah, let’s do that.

Jacinta: [00:06:42] Today, we have Dr. Griffin Foster talking to us. Hello Griffin. Tell us who you are.

Griffin: [00:06:46] Hello, I’m Griffin Foster. I’m a researcher at the University of Oxford.

Jacinta: [00:06:50] And what are you doing here in South Africa at the moment?

Griffin: [00:06:54] Right now, I’m at the Bursary conference, the student SARAO Bursary conference. This morning I gave a talk on what Breakthrough Listen is, the idea of how we do SETI and why we search for life.

 Specifically how Breakthrough Listen on MeerKAT will work. Basically we will be doing this large commensal backend, which will run anytime MeerKAT is doing scientific observations.

Jacinta: [00:07:22] So I watched your talk at the conference this morning and I really enjoyed it. You started by talking about single celled organisms and their evolution to what we know is life now.

Griffin: [00:07:33] A few years ago, I sat down  when I first started working through Breakthrough Listen,  I’d think about what do we know about life? And I realized my knowledge goes back to basically when I was in high school and took biology. I didn’t know what the current research was. So I spent a bit of time reading about this and I was surprised to learn, actually, that of course, you know, biologists have spent the past few decades figuring this stuff out to fantastic detail about how one of the main theories is these hydrothermal vent structures were formed that were fairly long lasting, long lasting enough to allow for life to form by basically creating these kinds of cavities, which had potentials between them and kind of acted like a cell before there were cells. And over time, these structures kind of became detached from the vents.

And as time went on  they formed these basic forms of life, you know, and there’s prokaryotic cells. From there planet earth chugged along for quite a long time. It took this kind of special moment. It’s a very rare moment in the story of life where these prokaryotic cells at one point in time decided to engulf another one, a few maybe, and instead of destroying it, it kind of incorporated in kind of the beginning of a eukaryotic life and what’s made a multicellular organism possible.

This moment happened, and it engulfed a chlorophyll, so it could do  photosynthesis or engulf something that was like this prototypical mitochondria, so it could do energy production and, kind of complex life shot off from there. And from there it was kind of a slow progress, but there was kind of a steady progress to multi-cellular life.

And then, these various forms of life until here we are now, this kind of life that can form abstract thoughts and build technology and really allowing us to then ask, well, why can’t there be other life out there very similar to us? Maybe not physically, but kind of the same ability to think beyond a basic survival, kind of more complex, informed societies and advance our knowledge.

Jacinta: [00:09:47] So basically one cell ate another cell, and then evolution continued leading to life as we know it today. And then that then leads to the idea that there could be other life out there in the Universe and that we could search for it. So throughout the history of humanity, what has been the search for extraterrestrial intelligence?

Griffin: [00:10:07] Just to start, you said it ate the cell, but that’s just it fundamentally, it didn’t eat the cell it incorporated it. That’s a big leap. Right. Before it would always eat it. Now, it didn’t. But I get your point. So humanity at some point, when we first realized there are planets, I think it was this general thought that, well, we’re on a planet there’s another plant out there. Maybe there’s life. And it’s quite interesting to think that for much of humanity’s existence, probably people thought, oh yeah, it’s reasonable that there’s something else out there. It’s only fairly recently that we’ve looked then gone oh yeah there’s nothing obviously there.

And maybe we’re alone. I’m not sure at what point that happened. But I think people have always been curious to figure out, like, can we communicate? And there’s some famous stories,  apocryphal stories likely about people digging big trenches and filling them with oil or kerosene and lighting them on fire and the hopes of like, signaling nearby planets to say hello.

Where they’re building crops or fields of crops in weird shapes, geometric shapes to show off to some other nearby planet oh yeah, we have an idea of geometry. These are great stories. But I’m not sure how many of them are real. The first attempt to look for life beyond Earth in a kind of a systematic scientific way happened about a hundred years ago.

The invention of radio made people realize that you can transmit information across great distances at great speeds. That led people to think, well, why can’t we transmit to other planets and why couldn’t they transmit to us? This happened early in last century. But it was really the development of the radio telescope, post World War II where we developed a lot of radar technology and started understanding how noise works, how information is carried and how we would utilize that.

People started thinking more kind of seriously about how one would send a signal. The first papers were written in the late fifties and early sixties. The first paper on radio SETI happened in 1959. Just the idea of fundamentally, and to this day, in fact, the most basic signal we can think if we wanted to make ourselves known and what we presume an advanced civilization would want to make themselves known would be, a very narrow band carrier wave.

A typical radio station has a carrier wave with information on the side, but you kind of tune in to that carrier. And so we would think  maybe an advanced civilization would do the same. It’s a great way to transmit at great distances. Say you have a given energy budget, and by concentrating it down to a very narrow frequency you can transmit that energy at greater distance.

And so to this day in fact, the kind of the standard, the bread and butter SETI observation that we do is to look for these narrow signals. Being incredibly narrow we can notice any sort of drifting and frequency. And there’s a drift in frequency because we’re on Earth. We’re spinning around on the Earth, which is spinning around the Sun, which is spinning around its own part of the Galaxy.

So we’re in a very particular reference frame, which as astronomers we know all about. We have to correct for all often times when we do observations of pulsars or anything that’s kind of variable in time.  We have a very particular reference frame so if we saw a signal that was kind of drifting, Doppler red shifting or blue shifting, we would have a sense that that must be because it’s in a different reference frame.

And we would never really expect a signal from an advanced civilization to be in the same reference frame because they’re spinning around their own star, on their own bit of the galaxy and on their own planet. So that back in the late fifties, that’s when the idea started and we still stick to it.

And it is a kind of a, what’s the dumbest thing we can do? And that was what was thought first. Of course there’s a ton of other ideas people have and there’s a lot of philosophy into you know, what’s the best way to search? Should we even search? What does it mean to look for life? But   if we want to do something practical, this is what we tend to do.

And we kind of expand from there and try to  look for other signals as we kind of think of them up but that’s what we stick to. Also in the late fifties, early sixties another type of  SETI was thought of, and instead of doing the radio, you’d do optical SETI, we call it . That’s because back in the early sixties lasers were developed.

It turns out lasers are a very good way to transmit information great distances, because you’ve basically made a coherent beam that you’re transmitting out.  If you know where you want to send the signal to you can point your laser at it and shoot at it. So the idea is we could do the same. As maybe some advanced civilization is shooting shiny lasers at us.

And then we could find that also within by using our optical telescopes.

Jacinta: [00:15:34] So there’s been this whole history of SETI. Why are we doing it now?

Griffin: [00:15:38] You know, I’ve been doing astronomy for maybe a decade now, maybe more. I did my degree in astronomy and astrophysics. It wasn’t that long ago when I was doing my degree and taking my course, there was kind of this unknown about whether there’s exoplanets or not.

Everyone kind of assumed there was, but there wasn’t really much evidence other than a few particular examples. And over this last decade, last 20 years, there’s been this boom and we now know that there’s planets everywhere. Most star systems have a planet, if not many planets. And the fact that we know this now is kind of an exciting thing.

This idea that of course there’s so many planets. I mean it seems so obvious now, but we now have this evidence and an obvious question next is when there’s a planet, what’s on this planet? Do they have atmospheres? Do they also have life? And people are, are kind of moving from finding planets and now figuring out what these planets are made up of. And this is a really a great moment because at the same time, this kind of brings forward the idea of doing SETI again. I think over the past few decades SETI’s been very quiet. People continue to do research in it, but I think this kind of discovery of exoplanets has really boosted the interest in SETI again. What’s happened about three years ago this kind of interest built to a really phenomenal event is that the Breakthrough initiatives. Which is this organization founded by some fairly interested people, but also fairly rich people who wanted to fund science to look for life beyond Earth in a number of ways.  The initial project is called Breakthrough Listen and Breakthrough Listen is a project that’s funded for over 10 years. It’s been going for three years now to use radio telescopes to look for  signatures of advanced life on other planets.

Jacinta: [00:17:29] So what is the Breakthrough project working on at the moment?

Griffin: [00:17:33] Right, when we started three years ago we kind of came up with some foundational goals.

Broadly, we want to survey, if not all nearby stars, a significant sample of them. We picked a number ambitiously, we want to do a million nearby stars. We also want to survey the Galactic Plane, and particularly the Galactic Center. You know, if you were an advanced civilization like us, you would build telescopes and you would realize the Galactic Center is very interesting and you’d want to point telescopes there. And so it’d be a great place to put a signal if you’re a very advanced civilization who thought they wanted to be known. There’s this idea of a civilization might create a beacon, a lighthouse to shine basically and this beacon  can be directed in many locations, or it could be kind of in all directions.

And if you’re going to create a beacon, you might put it in places people would look. And the Galactic Center would be a great spot to do it because it’s fantastically interesting. And so we’re not just looking there, but kind of on all the other planets we’d be interested in finding a beacon. And then  the third point is we’re interested in looking at nearby galaxies.

For an extremely advanced civilization with kind of unlimited energy budget they might be trying to let other galaxies, nearby galaxies be known. That reaches more into the realm of science fiction about how this would work.  It’s beyond kind of our understanding of how energy and technology would work.

But it’s potentially, you know, this is exciting. Who knows what we’ll find. And so for the past three years, we’ve been using the Green Bank telescope in the United States, which is a hundred meter steerable, a Gregorian offset dish. It’s a fantastic instrument that’s in the Northern hemisphere.

And then we use the Parkes telescope  in Australia, and these are great dishes but they can only point at one thing at a time. And so it takes a long time, especially if we want to observe a million stars. It’s going to take a really long time. So in the past few years, we’ve observed a few thousand stars, but we need to go bigger because it’s going to take a long time to get a million.

So that’s where MeerKAT comes in. MeerKAT’s this fantastic array where we have 64 dishes that are quite small compared to these really large dishes. They’re 13 and a half meters. Which means they have a large field of view and they roughly have a one degree field of view, but it’s actually quite bigger if you want to take into account other structures.

 What this means is that we can look at multiple places within this field of view at once. And so we build what’s called the digital beam former. And there’s 64 of these dishes and add it all up they’re just as sensitive. They’re in fact more sensitive than the Parkes telescope. There’re about as sensitive as the Green Bank telescope. And so by combining them all together, we have this big field of view where we can see dozens of stars at once and then we can point, we can form these a little beams in multiple directions. And so it’s almost like having dozens of massive telescopes at once.

And this is going to allow us to observe a million stars over three to five years. Kind of the run of this initial large survey projects at MeerKAT.

Jacinta: [00:20:54] Well, you’re taking the Breakthrough Listen project from having looked at a few thousand stars to looking at a million stars. You must generate an enormous amount of data.

What are you going to do with this data and how are you going to process it?

Griffin: [00:21:07] That’s a fantastic challenge we have right now. We’re working on that right now. The MeerKAT system, because it’s so much data coming through, we have to do it in real time. We basically can’t save all the data, we have to choose what to keep.

And so we’re basically taking our processing pipeline, which typically we do this thing where we channelize the data down to very narrow bands. So the number we pick is roughly one Hertz, and that’s narrow compared to other radio astronomy. Most radio astronomy, you’re interested in tens of kilohertz, hundreds of kilohertz, maybe a megahertz band or more.

The reason we picked this is because we expect these kind of artificial signals to be incredibly narrow band. That’s another way that we’d indicate that something was artificial. You know, there’s this natural limit to how narrow natural physical processes are in the Universe. And we know this fairly well.

Masers are kind of the narrowest band things and even those are tens of kilohertz.  There is a natural maser it’s different than a laser or maser  that we make. But a natural maser is a cloud basically of elements within the molecules within the Universe that actually kind of coherently transmit.  Quite interesting objects that they can form a coherent transmission.

So once we do this narrow channelization, we then do the search where we look in to see if the reference frame is  different. A big challenge we have is the fact that humans make a ton of artificial signals. So we call this radio frequency  interference or RFI. And so we’re kind of, we have this problem where we’re looking for artificial signals in other artificial signals, and it turns out the vast majority of the things we detect are manmade things. And so we spend most of our time trying to get rid of those. We have good ways to do that, but still we’re  flooded with them. So we’re always trying to find new solutions. And in fact, there’s a limited number of us. And so we have kind of within our mandate, not only to find to seek out advanced civilizations or signals from the advanced civilizations, but make this as open as possible because we know that there’s not enough of us. And this is really a challenge beyond us. I mean, it’s really an interesting challenge that I think most people in the world can understand that and could be excited about and given that  we have limited time we want to make it possible for other people to help on this. And so not only is all that data open, we’re very open about what we search for, how we do it. We’ve created tutorials, our code is open and we strongly encourage interested parties to join in if they feel like they can contribute or want to contribute. You know we’re all aware of pop culture, we all are interested in it. We watch films or books and aliens get into pop culture quite often. And we think about this and a lot of times it’s fairly nefarious or there’s some like conspiracy theories.

And so, really an important aspect to us is that  we make sure everything we do is open. Everything we do is our codes open source. We’re very public about our discoveries, we want to make it very clear that everything we do is not nefarious.

Jacinta: [00:24:47] So you do want people to be involved in your search  for “aliens”, quote un quote.

 What about the general public? Can they get involved as well?

Griffin: [00:24:56] Yeah, absolutely. We are trying to figure out ways for everyone to be involved.  Not just skilled engineers and programmers and astronomers, but yeah, the general public. We’ve decided to start a project using Zooniverse and Zooniverse is this great project that’s been running for I’m not even sure how long, but well over a decade now. And it’s a citizen science project and started as a way to classify radio galaxies. And the idea would be that a bunch of scientists would upload images of radio galaxies that they just didn’t have time to classify. But they’ve built a tutorial and a guide for how to do it, and they sent it out into the world and they built a really nice interface and it was enormously successful.

And over the years the Zooniverse has expanded to a ton of other scientific project. There’s been a project to decode scraps of papyrus that people found in a rubbish bin from many centuries ago. There’s like a project to encode weather logs from the 18 hundreds. I mean, not just astronomy, but all these other really interesting things.

And they’ve built a really nice framework to allow us to create this. These projects are very accessible to mainly the ideas is for school children, but also high schoolers and general interested parties. And we’ve gone and built this little program where people will be able to go through all our signals and help us at least describe what they are.

As far as we know all these signals are human made, but, they’re really hard to figure out what they are and kind of filter through them and get rid of them. And so we need help to kind of classify them and this is kind of the entry point in how we build a model that will filter them out. We’re beta testing this Zooniverse project right now and hopefully in the next few months we’ll have the official announcement and we’ll get a lot of people to help us.

Basically the next step is really to build these models that allows us to kind of filter out all this human made radio frequency interference, and try to get to the astronomical signals.

Jacinta: [00:27:10] All right, so astronomers and the public and everyone are going to be searching for these radio signals from alien civilizations, but what actually makes us think that they want to talk to us?

What makes us think that they are putting out signals for us to find.

Griffin: [00:27:25] Well for me, a bit of optimism. A bit of a hope for humanity and hope for humanity that stretches off to other advanced civilizations. You know, you’re absolutely right.  You can take a pessimistic approach and think, well, you know, maybe they wouldn’t transmit signals.

 I’d like to believe that our own interest in this means that we’re curious  about the Universe and any other civilization would also be curious. And at some point decide, well, we’ve advanced technology sufficiently, we kind of have control of energy in a way that we’re comfortable with and that it might be reasonable to say something more, just try and say hello to the rest of the Universe and kind of make themselves aware or make other civilizations aware of themselves. Yeah, I think that it’s an optimistic dream, I guess. And I’m hopeful about that. I think that’s a reasonable thing because I’m hopeful for humanity.

Jacinta: [00:28:23] So are we transmitting any signals? Are we trying to communicate with aliens?

Griffin: [00:28:28] Well, indirectly we are, you know, this radio frequency interference I’m talking about is us transmitting. This is the radios, this is mobile data, this is radar systems. You know, the Earth has a radio leakage signature we call it, of just all the technology that’s leaking out around it.

Turns out the signature is actually, because it’s not directed and it’s not coherent, and  in a particular kind of focus, the leakage kind of fades fairly quickly. And so we might be able to detect a similar leakage from nearby planets, but really distant planets, it can be really hard. And so similarly, a civilization would have a hard time seeing our leakage, but we do have large radar systems.

We have this large planetary radar system. At Arecibo in Puerto Rico in the United States, which is used to map objects, near-Earth objects and things  within our Ssolar System. And that uses the radar system that we transmit to a very, very high power to map these out. But a similar system could basically be used to communicate at very large distances.

And in fact, this is what we typically use as a measure, an indication of kind of how far we could detect a signal.

Jacinta: [00:29:46] And there were concerted efforts  to put out a signal with Arecibo a few years, wasn’t there?

Griffin: [00:29:50] Oh yeah, yeah. Many years ago, in fact. But there have been in the past, and there’s been other radar systems where people have transmitted on to nearby stars.

And so there’s been these little moments, no long term kind of signal. And the signals are fairly basic kind of encoding little bits of mathematics into it. And figures. But we haven’t really done this  in a long  time or in a serious effort.

Jacinta: [00:30:20] That’s just the beginning for large radio telescopes  in South Africa. Of course, we’ve got coming up the international Square Kilometer Array, much of which will be built here in South Africa. This will be an even bigger instrument. Is there plans to perform SETI with the SKA?

Griffin: [00:30:36] Absolutely. I mean, this is, you know, MeerKAT is a fantastic instrument and it’s going to run for as long as it can and we can get amazing science out, but it will also be the core of the SKA mid-frequency array.

It won’t just when MeerKAT ends. Hopefully MeerKAT doesn’t end for a very long time. But it will continue with the SKA.

Jacinta: [00:30:59] You recently went to the MeerKAT site in the Karoo. What were you doing there?

Griffin: [00:31:04] Yeah. We installed our very first equipment there,  which has been very successful and we’ll be installing more equipment over the coming months.

You know, we announced officially in October that we’ll be doing this collaboration with MeerKAT. Of course, it’s been in the planning for a very long time and part of this planning has been to invest in the HCD program, the human capital development program that SARO has been running for a long time now.

And it’s this fantastic program. In fact, not too long ago, I was part of that program. I did my first,  research fellowship here,   after I did my PhD. And,   I couldn’t be more happy to be back. In fact,  there’s an incredible excitement in South Africa about doing radio astronomy, it’s probably the best place in the world to be doing radio astronomy at this moment.

 And I think the interest from SARAO to have us here has been great. And we’re excited to, you know, we’re based throughout the world and we want a presence here specifically. And we hope in the near future we have people that are not just contributing on a volunteering basis, but we’ll be kind of financially supporting them to expand, interest in SETI in South Africa.

And there’s really been a lot of great feedback and great support from South Africa. And,  I think it’s going to continue.

Jacinta: [00:32:29] Well, it all sounds very, very exciting. Thanks very much for talking to us today, Griffin.

Griffin: [00:32:33] Thank you so much.

Dan: [00:32:39] Great. Fascinating stuff.   I mean, I’ve always been skeptical. Like I don’t, I really don’t expect us to be able to detect anything. I mean, the scale of the Universe is so large that the chances of something being near enough and in the right developmental stage to be transmitting has always made me, and I think a lot of scientists is probably, a little disinterested in the actual search for extraterrestrial intelligence. But it’s great to see that people are doing it and taking it seriously.

Jacinta: [00:33:13] Yeah, and I guess if you don’t look, you definitely 100% are not going to find. Right. So somebody’s gotta be looking, and I think it’s worthwhile doing it, especially if you can do it at the same time as doing other science.

So you’re not losing telescope time. You’re not losing data products. You’re just gaining and why not?

Dan: [00:33:31] Yeah, I mean, I think that’s absolutely the point here. Like it’s kind of hard to motivate for spending time and telescope time and money on the search when the likelihood of finding something is so low. But if you can just piggyback on amazing science that’s already happening and possibly discover something incredibly amazing, then why not?

Jacinta: [00:33:54] Yeah, exactly. I mean, it’s high risk, high reward. I mean, if you actually found a signal that’s potentially from an extraterrestrial civilization, that’s game changing.

Dan: [00:34:05] Well, in this case, it’s pretty low risk, right? I mean, they’re using observations which are already happening.

Jacinta: [00:34:11] Right, exactly. So I think all in all, this is just awesome that it’s really happening and that it’s happening in a really rigorous scientific way and that it’s happening right here in South Africa.

Dan: [00:34:24] Well, I mean, I hope the aliens don’t take offense. Independence Day. They’re all going to come and kill us,

Jacinta: [00:34:31] Oh right. Oh, sorry. It’s been a long time since I’ve seen that movie.

Dan: [00:34:35] Gosh, it’s a classic!

Jacinta: [00:34:36] And that’s it for today’s episode. Thanks very much for listening and we hope you’ll join us again for the next episode of The Cosmic Savannah.

Dan: [00:34:44] You can follow us at thecosmicsavannah.com that’s Savannah, S A V, A, N, N, A, H, where we will have links related to today’s episode.

Jacinta: [00:34:53] Special thanks to Dr. Griffin foster for speaking with us.

Dan: [00:34:58] Thanks to Mark Allnut for the music production. Janus Brink, for  astrophotography and Lana Ceraj for the graphic design to create the podcast art. This episode was created with the support of the South African National Research Foundation and the South African Astronomical Observatory.

Jacinta: [00:35:12] We’ll speak to you next time on The Cosmic Savannah.

Dan: [00:35:19] Next time on The Cosmic Savannah.

Lerato: [00:35:21] They were wondering like, what is this bright star like that shines in their radio? What is it? And later on with better instruments, with better telescopes, they were able to see that, okay, no, actually there’s more to it.