Episode 22: Milky Way blowing bubbles!
with Dr Fernando Camilo
This week we are joined by Dr Fernando Camilo who is the South African Radio Astronomy Observatory (SARAO) Chief Scientist, where he directs the scientific program of MeerKAT to ensure the maximum scientific productivity of the telescope.
We chat with Fernando about MeerKAT and the incredible science it is doing. In particular, we discuss the recent discovery of enormous balloon-like structures that tower hundreds of light-years above and below the centre of our galaxy.
Caused by a phenomenally energetic burst that erupted near the Milky Way’s supermassive black hole a few million years ago, the MeerKAT radio bubbles are shedding light on long-standing galactic mysteries.
This week’s guest
Dr Fernando Camilo
Featured Image:
A radio image of the centre of the Milky Way with a portion of the MeerKAT telescope array in the foreground. The plane of the galaxy is marked by a series of bright features, exploded stars and regions where new stars are being born, and runs diagonally across the image from lower right to top centre. The black hole at the centre of the Milky Way is hidden in the brightest of these extended regions. The radio bubbles extend from between the two nearest antennas to the upper right corner. Many magnetised filaments can be seen running parallel to the bubbles. In this composite view, the sky to the left of the second nearest antenna is the night sky visible to the unaided eye, and the radio image to the right has been enlarged to highlight its fine features.
Related Links:
MeerKAT: https://www.sarao.ac.za/science-engineering/meerkat/
Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event, by I. Heywood et al., is published in the 12 September 2019 issue of Nature. The article is available at https://nature.com/articles/s41586-019-1532-5
Episode Transcript
(By Sumari Hattingh)
Dan: [00:00:00] Welcome to The Cosmic Savannah with Dr. Daniel Cunnama
Jacinta: [00:00:08] And Dr. Jacinta Delhaize. Each episode, we’ll be giving you a behind the scenes look at world-class astronomy and astrophysics happening under African skies.
Dan: [00:00:17] Let us introduce you to the people involved, the technology we use, the exciting work we do, and the fascinating discoveries we make.
Jacinta: [00:00:24] Sit back and relax as we take you on a Safari through the skies.
Dan: [00:00:35] Welcome to episode 22
Jacinta: [00:00:36] Hi, welcome back. Today we’ll be talking to the SARAO chief scientist, Dr. Fernando Camilo, about an exciting Nature paper publication that’s come out from the MeerKAT telescope where they found huge bubbles around the center of the Milky way.
Dan: [00:00:54] And SARAO is?
Jacinta: [00:00:56] The South African Radio Astronomical Observatory.
Dan: [00:00:59] Yes.
Jacinta: [00:01:00] I hesitated for a second. It used to be called SKA South Africa, and now it’s been renamed.
Dan: [00:01:08] So first we should probably let our listeners know that we know have transcriptions of our episodes available.
Jacinta: [00:01:13] Yes, that’s right. So we have a dedicated team of student volunteers who have very laboriously been going through and transcribing each episode.
I think almost all of them are done for season two and we’re yet to start attempting season one. So if you or anyone you know is perhaps hard of hearing or it would just help you to read along as you’re listening, head over to our website on the blog for each episode will be the full transcription of what we’re saying.
Thank you to our volunteers.
Yes, very much so. Yeah.
Dan: [00:01:44] We’ve received a lot of positive feedback about the podcast. Thank you to all our listeners.
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It helps us to reach new listeners if you can rate and review us. And of course, the one of the best way to spread the news is by word of mouth. So if you can tell your friends and family about us, if you think they’ll enjoy it, we’d be very grateful.
Dan: [00:02:17] Okay. So should we get into today’s episode?
Jacinta: [00:02:19] Yes. On to science,
Dan: [00:02:20] All right. Today we’re joined by Dr. Fernando Camilo, as you said, who is the chief scientist for the South African Radio Astronomy Observatory. And he’ll be talking to us about this exciting Nature paper.
Jacinta: [00:02:32] Yeah, that’s right. So he’s a big gun here in astronomy in South Africa, and we’re very excited to talk to him about this topic.
Several listeners have requested it. So in September, 2019 so at the end of last year. One of, I think it’s the first MeerKAT paper publication came out and it was published in the world’s most reputable journal – science journal – Nature, and only papers that are very, very important, which are presenting something very important or very new, some previously unknown phenomena are allowed to publish in Nature. This research was so significant that it was accepted. It was important because they found for the very first time, huge radio plumes or bubbles emanating from the center of the Milky Way. And this hasn’t been seen before in any galaxy.
So this is something brand new.
Dan: [00:03:24] So we should point out that by a radio bubble, we mean a big bubble of gas, which is visible at radio wavelengths.
Jacinta: [00:03:32] Yeah, that’s right. And bubbles had been seen before from the center in gamma rays. Very, very huge bubbles called fermi bubbles. And this is the first time it’s been seen in the radio.
So it’s a pretty big deal. And we don’t yet know what’s causing it. It could have something to do with the supermassive black hole at the center of the Milky Way called Sagittarius A star. Maybe that’s ripping apart stuff, some stars and gas and dust and creating these bubbles, or it could be a sudden burst of supernovae.
We’re not really sure yet, but Fernando tells us the backstory behind this discovery and what led to it.
Dan: [00:04:07] Yeah, it’s great to see MeerKAT already producing world-class science, getting into Nature, and I think that we’ve got some exciting years ahead.
Jacinta: [00:04:15] That’s right. So MeerKAT, as we have discussed in previous episodes, is one of the most powerful radio telescopes in the world.
It’s right here in South Africa in the Karoo. It’s fairly new. It consists of 64 antennas, which looks kind of like satellite dishes and they’re picking up radio waves from space, and one day it’ll be incorporated into an even larger telescope called the SKA, the Square Kilometer Array Radio telescope. And this is just as, as you’ve said, just now, Dan, the beginning of a huge revolution in radio astronomy and science discoveries.
Dan: [00:04:48] We should probably also point out the recent news about MeerKAT, that there was a further investment from Germany to expand the 64 dish array with an additional 20 dishes.
Jacinta: [00:04:58] Gosh, very exciting.
Dan: [00:04:59] So that’ll also lead into the SKA. Ultimately. But this is funded and this will be happening over the next two years.
So we expect those dishes to be going online next year. 2021
Jacinta: [00:05:10] so soon. That’s exciting. Oh my goodness. I didn’t even know about that.
Dan: [00:05:14] It is
Jacinta: [00:05:15] hot off the press.
Dan: [00:05:16] Exactly. So there’s some, some really exciting stuff happening.
Jacinta: [00:05:18] Yeah. And there was actually also another Nature paper incorporating MeerKAT released at the time of recording.
It was released this week, on Monday. The…
Fernando: [00:05:28] Second
Jacinta: [00:05:29] Second, I think it was the 2nd of March, and that was about a low mass binary system, which if you’ve heard episode 21 you know all about that. When we talked to Tana Joseph, she explained what that was. It’s a black hole with the star going around it, and in this case it seems to be releasing this huge jet of radiation, which is traveling very, very fast, and it’s super luminal, which means it’s traveling faster than the speed of light. Yes. Well, it appears to be traveling faster than the speed of light, but of course we know that nothing in the universe actually can. Anyway, I’m revealing too much. We’ll, we’ll leave the rest for another episode that’s coming up very soon.
Dan: [00:06:05] Okay. I think we should hear from Fernando. It was wonderful to chat to him. Great interview.
Jacinta: [00:06:10] Yeah, let’s hear from him.
intro_music: [00:06:13] music intro
Dan: [00:06:18] Today. We are joined by Dr. Fernando Camilo, who is the chief scientist at the South African Radio Astronomy Observatory, SARAO. Welcome to The Cosmic Savannah.
Fernando: [00:06:27] Good morning. Thank you.
Dan: [00:06:28] Fernando, if you can just start by telling us a little bit about yourself and how you got to be here in South Africa. You’re not originally from South Africa and how you got to be working at SARAO.
Fernando: [00:06:37] Yeah, sure. That’s right. So I’m not from South Africa. You can tell from my accent. I was born in Portugal, and then when I was 18 I went to the US to study and I did most of my career there. I was a an astronomer studying pulsars, these very tiny neutron stars. And then in 2015 I received an email that had some results from the first MeerKAT dish.
MeerKAT is a big radio telescope up in the Karoo. And I had known – I’d first heard of MeerKAT back in 2009 when the SKA South Africa project had issued a call for proposals from the international community to use this feature. Very, very exciting. A sensitive new radio telescope that was going to be built in South Africa called MeerKAT.
So I was part of one of the teams that was awarded some telescope time back in 2009. But then our South African colleagues went about building this MeerKAT telescope, and in 2014 the very first dish, MeerKAT is made up of 64 dishes separated by up to eight kilometers up in the Karoo. I received a plot that showed the sensitivity of this one dish.
And I was really stunned because it was roughly twice as sensitive as we have been led to believe back in 2009. I went back to my notes to confirm that was the case, and this is very unusual because when you build these high tech projects, you’re very lucky if you reach the design goals, you don’t surpass them by a factor of two.
So I was very interested about that. I contacted my colleague, I said, there must be some factor of two wrong in this plot. Someone forgot to divide by two or something, and a few days later he confirmed to me that, no, this is real. This was the sensitivity of a MeerKAT dish. And at that point I got really interested.
Well what’s happening? Because South Africa didn’t have really a very large profile on the international radio astronomy community, let’s say. And so that led me to, in 2015 I came, there was this job opening SKA South Africa chief scientist, and I thought of doing a career change and moving to a different country and doing a different job.
And yeah, I ended up coming here because of MeerKAT. Now back in 2016 when I arrived, MeerKAT was still being built. The very first image hadn’t even been been made. But since then, in the past two or three years, a lot has happened.
Jacinta: [00:08:47] So this telescope was designed and then it ended up twice as good as it was planned to be.
Fernando: [00:08:52] Yes. Something like that. It’s remarkable.
Dan: [00:08:55] So how, how was that achieved exactly, right? Maybe not. Exactly. Yes.
Fernando: [00:09:00] That was the question I had from my colleagues here in South Africa when I arrived for my job interview back in September of 2015 and I spent three or four days in Cape Town, you know, apart from the job aspects of it. I was trying to figure out if I’d like to move to this beautiful city, which I’m very glad I did, but I said, I remember sitting down with one of the brilliant engineers in the office and asking him just that, ah, how did you do this? And the funny thing was basically, long story short, it was all about design, engineering, optimization of a design.
So it’s an interesting thing also, sociologically from the perspective of science, sociology, if you will, in South Africa. South Africa, as I said, didn’t have much of a history of radio astronomy, so it didn’t have too many radio astronomers. Now when you go and build a new radio telescope in Australia, or in the United States or in the Netherlands, all countries that have a very long history of radio astronomy, of course there’s engineers involved, but also the astronomers are very much involved in building the radio telescope.
You know, some of the old timers, probably built the first Radio telescopes with their hands and so on. And so there are a lot of inputs into the design of a new radio telescope. But in South Africa because it didn’t have that history, what you did, however, have was a very proud and very long history of brilliant engineering.
Something to do with the history of the country, the details of it. But in any case, there’s brilliant engineers in fields like radar technology. Which are very much relevant for, for building a radio telescope. So long story short, the way that my colleagues went around building MeerKAT was really substantially different from what a normal, the way normal telescopes get built around the world.
So it had a lot more engineering input, a lot more design, reviews. I like to joke that with MeerKAT, you don’t build the screw unless there’s 300 pages of documentation and one of the results of that is, well there, there are many consequences of that. So one is that by optimizing every single bit of the design and then re-optimizing, as that colleague of mine explained to me in 2015.
Our colleagues just squeezed out that last little bit of performance that you could from sort of a standard design, and then these telescopes are incredibly complex machines. I mean, they’re really data machines that generate enormous amounts of data. There are many subsystems that all have to work together, and it’s very complicated.
So many of these telescopes when they get built and they get inaugurated, like MeerKAT was inaugurated in 2018 often, it still takes, takes a year thereafter to, to generate science, to generate very nice images because it takes so long to commission; to understand it backwards and forwards. But MeerKAT pretty much just work right out of the box because of that care and thought that went into the design and the design reviews and prototyping and so on.
So pretty much worked right out of the box and led to some very, very nice images that we are seeing today.
Dan: [00:11:51] And not just images. I mean science, right?
Fernando: [00:11:53] Of course. Ultimately it’s about science. I mean, it’s funny, we, we, these days there’s this discussion about big data and big, the words, big data everywhere.
And I was just thinking about this actually the other day. So you think of Google that we all use, right? And of course they’re involved in big data, but their business is really about making money. That’s what Google is about. It’s a public company. It’s either shareholders. Well, when you, when you look at a telescope like MeerKAT, our business is not data.
Our business is science. So we collect lots of data. We’re all swimming in data these days. We have many telescopes of all sorts. But the key thing is how are you going to convert all that data into science, into, into answering new questions, into writing journal articles that explain, you know, what you’ve learned and so on.
And that in turn requires large numbers of very clever young astronomers, scientists, and so on, which now exists in South Africa. Because along the way with building this really world-class radio telescope here in South Africa. Some of our colleagues invested in the human capital development aspect of it, and so now there are far, far, far more young radio astronomers than they were a decade ago or so.
Jacinta: [00:13:04] So speaking of the amazing science that MeerKAT can produce, one of the very first papers that it produced was actually published in one of the world’s most prestigious science journals, Nature. And that was led by Ian Heywood, in Oxford, and yourself here and at SARAO. Tell us what the paper was about.
Fernando: [00:13:23] Yeah. So that was very, very interesting. So the result is very interesting. It turns out so that we on Earth going around the Sun once a year, we are in turn going around the center of our galaxy, the Milky Way galaxy, which is a large spiral galaxy. And we go around the center of our galaxy every couple of hundred million years or so, and we are roughly 25,000 light years away from the center of the galaxy.
So it takes light, including radio waves, 25,000 years to travel all the way from the center to us. The center of our galaxy is a very, very interesting place. It’s unique. Of course, there’s only one center about which we rotate, but it has a very massive black hole, so there’s a black hole at the center that weighs roughly 4 million times as much as our Sun.
So all sorts of things happen near the center of our galaxy that don’t really happen anywhere else. So astronomers are always very interested in looking at what’s happening at the center of the galaxy. This paper reports the discovery of these massive bubbles, the this sort of this bipolar outflow North and South of the center of the galaxy to these plumes of radio waves.
Over a thousand light years in length that we discovered with MeerKAT and nobody knew they were there, so we discovered that. Then in the paper we explained what we think that might be due to some sort of explosion – explosive events that might’ve happened at the center of the galaxy 7 million years ago or so.
So that’s, I mean, the science of it. And then people will do more detailed work and follow-up work, investigating what does this mean for other things we know at the center of the galaxy. So it’s all about basically understanding our environment in which we live on the galactic scale. And this was an important additional discovery.
Now there’s this very interesting backstory behind how we got to writing this paper, how we got to have these data that we analyze and finding these bubbles. So if you go back to early 2018 about six or seven months before the telescope was inaugurated, our colleagues are engineers at SARAO. We’re still developing many key capabilities of the telescope that were required to make it work as a functioning telescope.
So it’s made up of 64 dishes, large dishes, each of them roughly five stories high, up in the Karoo, as I said earlier, separated by up to eight kilometers. Now the dishes were all there. The dishes had been standing there for many months, since 2017 but a lot of the electronics behind it, etcetera, were still being developed.
And finally, it was on April 19th of 2018 when for the very first time, we had 64 MeerKAT dishes, all pointing in the same direction, collecting data from the same star or galaxy that we pointed the telescope to. So that was April 19th. Now. We knew that on July 13th that was going to be the inauguration of the telescope and that date wasn’t going to change.
And so we of course had to come up with some nice images to, to present to the public, to the distinguished guests that were there for the inauguration. And we were thinking about what to do. Now the sky is vast, you can point the telescope anywhere and find interesting things. And one day in May, – I remember it was early May – one night we had telescope time. That is, it was free that it wasn’t being used for tests. I think it was Ian, the first author of this paper myself thought, well, why don’t we point a telescope at the center of the galaxy. Eventually everyone who has a new telescope wants to pointed at the center of the galaxy, if they can.
But that usually takes years because the center of the galaxy is a messy place. You know, it has all these bright features and dim features and large extended scale structures and small features and all of that makes it just technically very complicated to come up with a decent image with radio waves, but we thought, Oh, what the heck?
We have these eight hours or so tonight, let’s do it. And then to our surprise, it came out really well. It looked good. And so then basically we spent the next month doing further observations to assemble this picture that we released at the inauguration on July 13th of 2018 – a very, very beautiful picture.
The clearest view of the center of the Milky way that has been done to date, with any telescope around the world. Now that was essentially for public relations purpose, right? That image was made for the inauguration of the telescope. Now we knew when we had it that the underlying data was also going to be useful for science, some science, but that required someone spending months and possibly years actually analyzing those data carefully.
Well, when we started looking at those data after the inauguration, I think in August of 2018, we soon found these funny features North and South of the center of the galaxy. We thought, whoa, that looks like a bubble up there. And the bubble down there and they seemed to be continuous. And then that was really the story.
And so that was August of 2018 and it’s took us, well, the better part of a year because he had to analyze the data fully and then to write the paper. And the paper, by the way, there are a handful of authors that did detail work on the specific dataset for the paper, but the authorship of a paper consists of roughly 100 people.
And the reason for that is that 95 or so of those people are people that had a critical role in building MeerKAT. There are what we usually call them, the MeerKAT builders list. Without those people, including policymakers, including managers, engineers, scientists, industry partners, university partners, MeerKAT just wouldn’t exist though.
They’re mostly South African, not entirely. So yeah, it’s an interesting story. Came about accidentally, but we’re very glad that we have it.
Jacinta: [00:18:53] How did you feel when you first saw those bubbles?
Fernando: [00:18:56] We were really, really happy. I mean, just visually we thought, okay, this is unusual. This is striking. This must mean something interesting.
Now those of us who looked, Ian and myself were, we’re not experts in the center of the galaxy these days. Radio astronomy, like many sciences, is very specialized. I’m an expert on pulsars and I know very little about the center of the galaxy. So even though Ian and myself spent the next year, well, learning a lot and reading lots of papers about the center of the galaxy so we could write a paper.
So we brought on board a colleague of ours from the United States, Furhad Yusef-Zadeh at Northwestern University, who’s an expert in some aspects of the physics of the center of the galaxy. So that also shows nicely the collaborative aspect of science these days. You know, it’s very international. And even MeerKAT, of course, we want young South African scientists to use it, it’s best done if we do this collaboratively with all the experts around the world.
But it was one of those things that sometimes happens in science. You look at it, you know, you have something, the minute it pops up on the screen, to your face. But then it can be quite a lot of work to actually disentangle the details and figure out what it really means.
Dan: [00:20:08] This discovery. Why MeerKAT? Why has this never been seen before?
Fernando: [00:20:13] That’s a very good question. Until MeerKAT, the, let’s say, well, the gold standard, and still in many ways, the gold standard of radio telescopes of this sort what we call the interferometer is made up of these many dishes put together, is the so-called Very Large Array in New Mexico in the US.
Although we can see the center of the galaxy much better from the Southern Hemisphere, which I’ll come back to in a minute, from the United States you can also look down towards the center of the galaxy for a few hours a day or each night. And so the very larger, I had made some images of this region in the best, and it had found some very interesting features, which we now see better with MeerKAT. But it didn’t quite have the technical capabilities to find these bubbles. Now, why these bubbles are actually relatively faint. They’re very extended large structures. And so the advantage we have with MeerKAT is two or three fold. So first of all, location. So it just so happens that the center of the galaxy, the center of the Milky Way goes right overhead.
Where MeerKAT is located is in the Northern Cape. So that means we can look at it from rise till set for approximately 12 hours a day or night because it’s radio waves and we can observe 24 hours a day. So we can look at it for 12 hours a day. Whereas say in the US you can only look at it towards the South, hugging the horizon for say, four hours.
So that’s one big advantage. Second advantage is that MeerKAT is now the most sensitive radio telescope in the world. At these frequencies that we operate at. So we collected radio waves with the frequency of roughly 1000 Mega Hertz. So roughly 10 times frequency of your FM dial at that frequency, MeerKAT is the most sensitive telescope in the world.
So that helps a lot. The one thing that helps tremendously is the number of what we call “baselines”. So it’s the number of dish pairs. If you think about it, if you consider a telescope with two dishes – made up of two dishes separated by, I don’t know, a hundred meters.
Well, there’s only one way in which you can combine those two dishes. Now, as you start adding more and more dishes, the number of possible pairs goes up as the square of the number of dishes. So with MeerKAT’s 64 dishes, you have 2016 possible combinations of dish pairs. And ultimately that allows you to make much sharper images of the sky, higher fidelity images of the sky.
These interferometers radio telescopes like the kind that MeerKAT is, don’t produce perfect images of the sky. There are always some artifacts, and the fact that we have 64 dishes in 2000 of these dish pair combinations, allows us to make essentially the highest fidelity images of the radio sky, than any telescope of this sort can make.
So all of those put together allowed us to make this discovery. There’s one additional thing, of course, which is normal telescopes, telescopes that are in production, allocate their telescope time on the basis of proposals that are submitted by scientists. Scientists want to investigate some phenomenon. They write a scientific proposal, say, I want 100 hours of telescope time to study this, that, and the other.
Now, we didn’t have to do that in this case because we had other constraints, other requirements; we needed to inaugurate the telescope. So we had the flexibility to, in particular, the moment we saw that we had something interesting that night in May of 2018, we had the flexibility to then spend the next month going back to this region of the sky to really study it very well.
So it was serendipitous. It was very exciting. And I’m very glad this was the first paper that was produced that was put out there based on the full MeerKAT – on the full 64 dish MeerKAT.
Jacinta: [00:23:54] This is obviously a very exciting discovery and very important for the scientific community. Since it was published in a journal as prestigious as Nature.
Why was it so important and what caused these bubbles? I know these are two different questions, but the Milky Way is sort of more or less flat, like a dinner plate. We’ve got the center and then we on Earth, are sort of a little bit further out on the plate revolving around that center. And then these bubbles are coming above and below this plate, this plane of the Milky Way.
And they’re enormous. So what could possibly be producing so much energy that it could blow out these bubbles? And, and why is this important for us to know about?
Fernando: [00:24:33] Yeah, so, excellent question. As I mentioned earlier, at the center of the galaxy, there’s a massive black hole, 4 million times the mass of our Sun.
And what happens is that once in a while, gas and maybe stars that are nearby that black hole, they are swallowed up, or part of them are swallowed by the black hole. And maybe they’re torn to shreds in the process if a star, you know, falls into the black hole. And so there’s a lot of energy involved. And somehow through very complicated means that we don’t yet fully understand in galaxies in general, but some of is this energy is emitted.
This gravitational energy ultimately is emitted along generally in an axial direction. In this case, maybe North and South of the center of the galaxy. Now, we know of other features of the bubbles, etcetera, around the center of the galaxy, there are very famous so-called Fermi bubbles. They were discovered by the NASA’s Fermi Gamma Ray satellite back in 2010 or so, and these are enormous bubbles, much larger than the MeerKAT bubbles.
They spend roughly 50 degrees on the sky, North and South. Now, for comparison, the Moon on the sky subtends an angle of half a degree. So imagine on the sky bubbles that are a hundred times wider or taller say than the Moon, right at the center of the galaxy. These are the so called Fermi bubbles, and we don’t fundamentally understand what caused them.
And likewise, we don’t yet know what’s caused these MeerKAT bubbles that are smaller than the Fermi bubbles. They might be related. We’re not sure, but generally there are two sort of options. So one is, like I said, matter falls into the black hole periodically. It’s not always a constant flow of mass and stars being torn to shreds, perhaps in falling into the black hole.
They can be periods of higher or lower activity. So that’s one option. And the other option is that in a place like the center of the Milky Way, again, a very busy place. Once in a while, meaning over timescales of hundreds of millions of years, the star production rate increases tremendously. You can have periods where many, many more stars and massive stars are being formed.
And then some of these stars explode. And supernovae are the most massive explosions in the Universe. And those supernovae released a lot of energy, mechanical energy into the interstellar medium, which push out other outlying gas and so on. So these bubbles, the MeerKAT bubbles, could also have been produced by such a phenomenon and for technical reasons that we go into into paper.
We think something may have happened roughly 7 million years ago that caused these bubbles. So that’s one estimate of the age of these bubbles now. So that’s interesting for our own galaxy to understand a little better. You know, the environment that we find ourselves in, but of course our galaxy is just one amongst hundreds of billions in the Universe.
So many of us want to understand more generally how galaxies form, how they evolve. And in fact, that’s one of the key MeerKAT projects or goals with many types of observations to address this question of, you know, how does a galaxy like the Milky Way, which is say, roughly 10 billion years old, the universe is roughly 14 billion years old. Our galaxy is a little younger, but how did the galaxy come to be the way it is? How did we come to be here the way we are today? It wasn’t always dust like this but by looking at many galaxies throughout the Universe with MeerKAT telescopes, we do hope to understand better that process, that history, but of course, as with many things, the center of our galaxy is the closest center of a galaxy that we have.
So these MeerKAT bubbles, for instance, if they are present in many of the galaxies throughout the Universe, it’s really unlikely that we’ll be able to detect them. They’re so far away and so faint. So this allows us to have basically a closer example of a galaxy, namely our own, to study in great detail in ways that we cannot study other distant galaxies.
But of course, the idea is we’re not special. It’s just that we are closer to our own central black hole.
Jacinta: [00:28:23] So MeerKAT detected a phenomenon that’s no one’s ever seen before.
Fernando: [00:28:27] That’s correct. That’s correct. And now MeerKAT, I mean, of course, this is the first example, but we have already been sharing data from MeerKAT with some of our colleagues in South Africa.
Many, many colleagues at universities, at the South African Astronomical Observatory, dozens of proposals, scientific proposals have been accepted and data has been shared. And our colleagues are analyzing those data. And soon I expect they will write their own papers, make new discoveries.
Dan: [00:28:55] This is an amazing discovery, obviously about the center of our galaxy, the gas around it.
We learn something about the supermassive black hole and how it interacts with that gas and, and our galaxy as a whole. What else are we gonna learn from MeerKAT?
Fernando: [00:29:11] Right. Very good question. So MeerKAT, as all instruments of this sort, they have to be optimized for something. MeerKAT is not the best in the world at everything.
Obviously, you know, when people ask me, so what’s the best telescope in the world? You can’t answer that question. Best for what? The Hubble Space Telescope that most everyone knows about circles up in Earth’s orbit, and it’s an amazing telescope. And it can do many things, but MeerKAT can do many things that Hubble cannot.
So these telescopes are optimized for doing something, and MeerKAT was particularly optimized to study hydrogen. Hydrogen is the most common, simplest element in the universe, and it’s the fuel that ultimately makes up stars and galaxies. Now, there’s a lot that we don’t know about how this raw fuel, raw material goes into making galaxies, you know, so hydrogen, it’s so happens; emits radiation or radio waves at the specific frequency of 1,420 Mega Hertz. So roughly 15 times the frequency on your FM dial, but it’s faint. So in order to study it from distant galaxies into this Universe, you really need a big so-called collecting area, a big bucket, very sensitive buckets. And that’s what MeerKAT is.
So MeerKAT was optimized. One of the things that was optimized for was to study hydrogen throughout the Universe from two thirds of the way across the Universe to today in our own galaxy and some of our own colleagues, including some of you are using MeerKAT.
Jacinta: [00:30:38] Yes. We have talked a lot on this podcast about using MeerKAT to study the hydrogen since that’s my field.
What are you most excited about for the future with MeerKAT discoveries?
Fernando: [00:30:49] Well, it’s funny.
Dan: [00:30:51] Without giving anything away.
Fernando: [00:30:55] No. I’m interested about everything. I remember discussing this question when I first came to South Africa back in 2015. I was thinking of taking this job and in the talk that I gave in the SKA South Africa office, I went through a bit of a history lesson with telescopes and I was showing what the Hubble Space Telescope was designed to do.
The reason why it was built, or at least a reason that someone used to convince the funders to pay the bills – to build the Hubble Space Telescope. And then when you look back at the Hubble Space Telescope 20 or 30 years later, it did do that project that it was originally intended to do rather well.
But particularly it did things that nobody had thought of. For instance, a Nobel prize was awarded for a fundamental discovery that tells us a lot about how our Universe evolves and expands and so on. That was originally made by the Hubble Space Telescope, basically. But the Hubble wasn’t designed to do that.
Nobody thought of that when the Hubble was designed. So, and this lesson is repeated throughout with other instruments, which is, if you have a relatively general purpose -really good instrument. You will make discoveries that you cannot foresee when the telescope is designed. And I’m fully convinced that this is the case with MeerKAT.
And in fact, these bubbles, I mean, these aren’t Earth shattering. They are, well maybe galaxy shattering in a sense, these bubbles, but it’s a very nice discovery. We expect there will be greater discoveries, but the points in the context of your question is that MeerKAT was not designed to study our galaxy at all.
It was actually optimized to study hydrogen in the distant universe and to study pulsars, ours as well, and a few other things, but making images of this sort isn’t really what it was optimized for, but as it happens, it’s very good at it. And this was the first, so our very first paper with a full MeerKAT was an example of a, you know, a spectacular unknown of sorts.
Yeah. A serendipitous discovery. So. I can predict, you know, scientists write all these long proposals that say we’re going to use all this telescope time to make all these great discoveries. And you know, for the most part, you end up making at least a fraction of those discoveries that you write down on your proposal.
And if MeerKAT does half of what my colleagues around the world have written down on their proposals that it will do, it will be doing very well. But in a sense, what I’m even more excited, just from a human perspective, is what I cannot think of today, the types of discoveries that it will make, like these bubbles and other things in our galaxy and beyond that we really cannot conceive of.
And you and your listeners also cannot think of. So maybe start thinking of what crazy unexpected things there might be out there and MeerKAT will probably make some of those discoveries. So 10 years from now, when we look back at what MeerKAT has achieved and continues to achieve, I expect that some of the things will have been totally unexpected.
Dan: [00:33:52] Well, we look forward to having a lot more MeerKAT episodes. So hopefully we have you back on soon to talk about some new and unknown discovery.
Fernando: [00:34:02] That would be great.
Jacinta: [00:34:03] Do you have any final messages for listeners?
Fernando: [00:34:05] Well, the messages, I understand you have listeners around the world. But this, hopefully a lot of them in South Africa, MeerKAT is a fully South African funded and largely South African designed machine.
It was designed, and it exists in the context of this much larger international project called the SKA, the Square Kilometer Array, which will start being built – we expect next year – also up in the Karoo and in Australia. But you know, I’m not South African, but I’ve been here almost four years now, and part of me starting to feel like South African, and I’m very proud of my colleagues and myself who I’ve have been involved with.
And I think every South African should really be very proud. When I go and give some presentations, talks to collaborators and so on, some of them are skeptical at first, and then they asked me three times or four times. This was really designed by South Africans? Are you sure? Like, come on. Yes, it was. It’s a South African project and it’s a brilliant project on the world stage.
It’s put South Africa out there in an area of research or South Africa hadn’t been very prominent and it’s just astonishing what clever people with vision and perseverance can do. I’m very proud of that, and I think the listeners who are South African especially should be very, very proud,
Jacinta: [00:35:19] We are very proud of South Africa.
Dan: [00:35:21] Fernando, thank you very much for joining us.
Fernando: [00:35:23] Thank you.
Jacinta: [00:35:24] I hope to speak to you again soon.
Fernando: [00:35:25] Thank you very much. So do I
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Jacinta: [00:35:35] All right. How cool was that?
Dan: [00:35:36] Yeah, very cool. I mean, we’ve talked a lot about MeerKAT and about how cool it is, how sensitive it is, how, what a good project it has been. Talking about how it came in past the sensitivity as it was designed to. It’s just been an incredible project that came in on budget on time.
More sensitive than planned. It’s something really that, you know, South Africa can be very, very proud of. It’s a South African project from start to finish and it’s producing what it was aimed to do now. Some incredible science and there’s just going to be more and more and more coming out of it.
Jacinta: [00:36:12] And how often do you build something and then it ends up better than you designed it?
Dan: [00:36:17] I think never.
Jacinta: [00:36:20] It was very rare, very exciting.
Dan: [00:36:23] The things that are going to come out of it. I mean, Fernando talked about a few of them. But there’s, there’s so much that MeerKAT can do. It’s, these bubbles are one thing, as he said, this wasn’t even what they were really looking for or what the, what MeerKAT had was designed to.
Jacinta: [00:36:36] It was an uknown unknown.
Dan: [00:36:39] Yeah. Well, yeah. So it’s one of those things we were stumbling on. There’s going to be a lot more things we stumbled on that we didn’t know. But then also there’s all the science that MeerKAT was planned to do, right? You know, we’re gonna map distant galaxies, and we’re going to understand a lot more about the universe than we did.
And other objects, pulsars. There’s a lot of potential there. There’s a lot of data coming already, it’s streaming out data. And at the moment I think we, the astronomers, are already overwhelmed. We’re not even in the SKA era. We’ve got more data than we know what to do with.
Jacinta: [00:37:12] Yeah, we’ve got data coming out of pur ears.
Dan: [00:37:14] Yeah. So a very exciting time to be a scientist. And I think that, for the public too, we are gonna make some awesome discoveries from here in South Africa.
Jacinta: [00:37:22] And I thought it was really cool, the concept that if you had radio eyes, if your eyes could see in the radio instead of the optical, you would see these bubbles extending like over a huge fraction of the sky.
And if you could see, if you had Gamma-Ray eyes, you’d see things that are even bigger.
Dan: [00:37:40] Yeah, so I mean, we can see the Milky Way. Well, if you’re lucky in the dark sky, you can see the Milky Way streaking across the sky, but in the opposite direction, you’d be seeing these massive bubbles blowing out as a center.
Jacinta: [00:37:53] Oh, how cool would that be if you had like Gamma-Ray glasses or Radio glasses and you could just put them on and see the plumes?
Dan: [00:38:00] Well, let’s hope that the gamma-rays don’t get down to us.
Jacinta: [00:38:04] Look, it’s a good point. You have to be in space to see it. It’s blocked by the atmosphere. Thankfully.
Dan: [00:38:10] We’ve got to keep this scientifically accurate.
Jacinta: [00:38:12] Yeah, that’s true. No, you’re right.
Dan: [00:38:13] Okay. I think that’s it for today. I think it was a very fascinating conversation with Fernando great to have him on and I’m sure we will be having him on again soon when MeerKAT makes another big discovery. Thank you very much for listening. As always. We hope you’ll join us again on the next episode of The Cosmic Savannah.
Jacinta: [00:38:29] You can visit our website, thecosmicsavannah.com where we’ll have the transcription and links related to today’s episode. You can also follow us on Twitter, Facebook, and Instagram @cosmicsavannah. That’s Savannah, spelled S-A-V-A-N-N-A-H.
Dan: [00:38:44] Special thanks today to Dr. Fernando Camilo for speaking with us.
Jacinta: [00:38:48] Thanks to Mark Allnut for music production, Janas Brink for Astro photography, Lana Ceraj for graphic design and Thabisa Fikelepi for social media support. Also to Brandon Engelbrecht for transcription assistance.
Dan: [00:39:00] We gratefully acknowledge support from the South African National Research Foundation and the South African Astronomical Observatory.
As well as the University of Cape Town Astronomy department for their support and keeping the podcast running.
Jacinta: [00:39:12] Yes, thank you for their new sponsorship of the podcast. You can subscribe on Apple podcasts, Spotify, or wherever you get your podcasts, and if you’d like to help us out, please rate and review us and recommend us to a friend.
Dan: [00:39:24] We’ll speak to you next time on The Cosmic Savannah.
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Jacinta: [00:39:35] Dum-dum…tssshh.
Dan: [00:39:40] You need bloopers that involve you, not just me.
Jacinta: [00:39:43] But I do the editing and I enjoy making you the blooper. Yeah. We’ve got data coming out of our ears pouring out of our…pours out. Okay. That’s for the bloopers.
I know, that is gross.
Didn’t know what I was going for then.
Dan: [00:40:05] It’s not even that hot today.
