Episode 10: Stars behaving badly!

with Dr Priscilla Muheki and Prof Hakeem Oluseyi

We are joined by two experts in stellar astronomy, Dr Priscilla Muheki from Mbarara University of Science and Technology, Uganda and Distinguished Professor Hakeem Oluseyi from the Florida Institute of Technology.

Priscilla talks about her PhD research in Uganda studying violent outbursts, known as coronal mass ejections, from certain types of stars.

Hakeem then goes on the explain these coronal mass ejections and the violent magnetic fields associated with them, and what effect they may have on both our technology and our entire planet!

Hakeem also talks about his visit to South Africa to assist in forming the African Astronomical Society (AfAS) and the incredible achievements of the South African National Astrophysics and Space Science Programme (NASSP) which has produced over 150 MSc Students and 90 PhD’s!

Episode Links:
Mbarara University of Science and Technology, Uganda: https://www.must.ac.ug/
Hakeem Oluseyi: https://www.fit.edu/faculty-profiles/4/hakeem-oluseyi/
AfAS: https://www.africanastronomicalsociety.org
NASSP: https://www.star.ac.za/

This weeks guests:

Transcript

(Please take note that Dan’s intro is not included in the audio, this is an episode 44 transcript that is a rerun of episode 10. Enjoy!)

[00:00:00] Dan: Hi everyone. Welcome to episode 44. This week, Jacinta and I will be taking a short break, and we will be playing one of our favorite episodes; stars behaving badly, which was episode 10. We hope you enjoy it. It was, as I said, one of our favorites, and I hope one of yours too.

[00:00:23] Jacinta: Welcome to The Cosmic Savannah, with Dr. Jacinta Delhaize,

[00:00:26] Dan: And Dr. Daniel Cunnama. Each episode, we’ll be giving you a behind-the-scenes look at world-class astronomy and astrophysics happening under the African skies.

[00:00:35] Jacinta: Let us introduce you to the people involved, the technology we use, the exciting work we do, and the fascinating discoveries we make.

[00:00:42] Dan: Sit back and relax, as we take you on a safari through the skies.

Welcome to episode 10.

[00:00:54] Jacinta: 10. Yay. We made to double digits. It’ll be a slightly longer episode today in celebration of episode 10. But I hope you make it all the way through, even if you have to listen in two parts, because we’ve got some, great guests with some really special things to say.

[00:01:10] Dan: Yeah, what are we talking about today?

[00:01:12] Jacinta: Today, we’re talking about stars behaving badly. So, we see stars in the sky and we think they look all innocent and pretty and sparkly, but they’re actually roiling balls of bubbling gas and plasma. And sometimes they do crazy things, and we call it stellar activity, where they have flares and coronal mass ejections, that whether the star suddenly throw off parts of their outer layers, and we’re looking at what happens to the planets around them when this happens, including the Earth, and also what happens to extra solar planets. We’re talking about pulsating stars, lots of good stuff.

[00:01:52] Dan: Our guests today are Priscilla Muheki, who is doing her PhD in astronomy at the Mbarara University of Science and Technology in Uganda, and Hakeem Oluseyi, who is a Distinguished Professor at the Florida University of Technology.

[00:02:06] Jacinta: Yeah. We got to chat with Priscilla and Hakeem, when they visited Cape Town recently for the astronomy in Africa meeting.

[00:02:12] Dan: Yeah. Which was a great meeting. The formation of the African Astronomical Society.

[00:02:17] Jacinta: Yeah.

[00:02:17] Dan: It was an event organized by the. Office for Astronomy Development, which is based here at the Observatory in Cape Town. And yeah, very exciting stuff.

[00:02:27] Jacinta: Yeah. So, first we’ll hear from Priscilla, and she’s on track to become the first woman to graduate from a PhD in physics, in Uganda and in Uganda Institute. And for her PhD, she’s studying, coronal mass ejections around M-type stars.

[00:02:43] Dan: Whoa.

[00:02:45] Jacinta: So, let me just explain that, there are two main types of stellar activity. There’s flares and there’s coronal mass ejections. And flares are like, bright flashes of light on the surface of the star, and it can result in the acceleration of highly charged particles, which can go streaming towards the planets that surround that star.

Now a coronal mass ejection, is also caused by realigning magnetic fields inside the star. But this is actually the ejection of a huge amount of highly magnetized particles, or plasma from the outer layers of the star. And this stuff actually goes hurtling towards space, and it can hit the Earth, or it can hit whatever planet is going around that star. And sometimes these clouds of plasma can expand out to be much bigger than the actual size of the star itself.

[00:03:37] Dan: And what is an M-type star?

[00:03:39] Jacinta: So stars are given a letter classification based on the kind of molecules that we can detect inside them. For example, the Sun is a GV-type star. An M-type stars, or just M-stars for short, by far the most common star type.

It’s important to study these because, many of the extrasolar planets that we’ve found, are going around M-type stars. Extrasolar planets being planets that are not in our solar system, going around the Sun, but going around other stars in different solar systems. So, we want to know what effect the star activity we’ll have on those exoplanets?

[00:04:19] Dan: Yeah. And whether it’s gonna be conducive for life, right? Or whether the star is gonna completely obliterate it.

[00:04:25] Jacinta: Obliterate it .

[00:04:27] Dan: Great. So, let’s hear from Priscilla

[00:04:36] Jacinta: With us now is Priscilla Muheki. Welcome Priscilla.

[00:04:39] Priscilla: Thank you.

[00:04:40] Jacinta: Priscilla, you are from Uganda and you work in astronomy. Can you tell us a little bit about yourself?

[00:04:46] Priscilla: I’m Priscilla Muheki. I am a PhD student at Mbarara University of Science and Technology, in Uganda. And I’m glad to be here.

[00:04:55] Jacinta: What got you interested in astronomy in the first place?

[00:04:58] Priscilla: First of all, we are a small community in the department of physics. So under the guidance of a professor, Associate Professor Edward Jurua who is the Head of Department, who’s trying to run a drive to promote astronomy in Africa, and especially in Uganda. And, basically we have courses in undergraduate studies. And as you study introduction to astrophysics, there’s so many fascinating things that you get to discover.

And eventually it motivated me to go ahead with astrophysics, from my graduate studies. And most of that, currently, there’s no female astrophysicist in Uganda who has completed from Uganda in particular. So it motivated me and I’m thinking, oh, I can make the name.

[00:05:50] Jacinta: You can be the first.

[00:05:50] Priscilla: Yeah. Yeah.

[00:05:51] Jacinta: That’s amazing.

[00:05:52] Priscilla: So, I was motivated to do my graduate studies. I did my master’s at the same university and later on enrolled for my PhD, which I’m currently doing.

[00:06:02] Jacinta: So, tell us about your PhD. What are you working on at the moment?

[00:06:06] Priscilla: Currently for my PhD, I’m looking at the effect of stellar activity on planetary atmospheres, in particular, around M stars. We know of this campaign to look for another habitable planet, and it happens that the biggest targets are M stars. So it’s very important to understand the properties of these M stars, and how they could influence the planets in.., around their system.

[00:06:34] Jacinta: Okay. So I’m not a stellar astronomer. Could you explain what an M star is? What are the different types of stars?

[00:06:40] Priscilla: There are different types of stars and they are classified according to their sizes to their luminosity, that is the brightness. And M stars are very cool stars with the effective surface temperatures, about 3000 Kelvin.

[00:06:56] Jacinta: Okay. And how does that compare to our Sun? For example?

[00:06:59] Priscilla: The Sun is about 5,700. So that’s like close to half of the temperature of the Sun.

[00:07:07] Jacinta: Okay, so they’re cooler. Are they bigger?

[00:07:10] Priscilla: No, they’re usually smaller in size..,

[00:07:12] Jacinta: Smaller. Okay. And what makes makes them interesting to study?

[00:07:17] Priscilla: What makes them interesting to study is because they’re very active. I mean, there’s a lot of activity on their surface and in their environment. So, they’re interesting because that activity brings about so many other issues that can actually influence their environment. And secondly, in the current, Coryton Kepler satellite, it has been discovered that about 75% of the targets are M stars in, within our galaxy.

So it makes it interesting because if they’re the biggest number of candidates, then it’s very imperative that you look at how best will they accommodate planets.

[00:08:02] Jacinta: What do you mean by targets? Targets to what exactly?

[00:08:05] Priscilla: In the exoplanet search.

[00:08:08] Jacinta: Oh, so searching for planets around other stars.

[00:08:10] Priscilla: Oh yeah.

[00:08:11] Jacinta: Right. And so you said that many of the stars that were selected to be looked at, to find extra solar planets are actually M type stars.

[00:08:21] Priscilla: Most of the planets that have been discovered are around M stars.

[00:08:25] Jacinta: Ah, right.

[00:08:26] Priscilla: Yeah.

[00:08:26] Jacinta: Okay. So it’s important to understand what’s going on with these M stars, and how active they are, and I guess how it affects the planets going around them.

[00:08:35] Priscilla: Yes. That’s true.

[00:08:36] Jacinta: So what kind of activity are we talking about? What sort of things can a star do?

[00:08:40] Priscilla: So, a star ca give out very high energetic particles, in form of flares and also plasma, through coronal mass ejections. So, basically those are the two most prominent, or energetic phenomena that take place on stars.

[00:09:01] Jacinta: So what’s a coronal mass ejection, CME?

[00:09:04] Priscilla: coronal mass ejection is, where there’s a very big energy. We have very big energies being released and a magnetic field from the Corona of the star.., I am not sure whether you actually understand the whole stellar structure, but the Corona is like the outside part of the star, like the atmosphere of the star.

[00:09:27] Jacinta: Okay. The surface.

[00:09:28] Priscilla: Yeah.

[00:09:28] Jacinta: Yeah. Yep.

[00:09:29] Priscilla: Yeah. So when you have very high energetic particles and magnetic field being released into inter planetary space, then we refer to that as a CME, or a coronal mass ejection.

[00:09:44] Jacinta: Does the Sun.., our star, does that have coronal mass ejections?

[00:09:48] Priscilla: Oh, yeah. It has several coronal mass ejections, and they are usually higher in number during very high active times.

The Sun has an 11 year activity cycle, where there’s decrease and increase in activity. So you’ll have some time when there are few coronal mass ejections. Sometimes they’re no, and that, during that time, it’s a quiet time. And then when it’s very active, you’ll have many coronal mass ejection. And these coronal mass ejections for the case of the Sun on Earth, we are affected by these coronal mass ejections not necessarily directly, but they interfere mostly with the space physics and equipment.

Because when these high energetic particles get into the Earth atmosphere, they reduce or interfere with communication and all that satellite thing. They’re very crucial in influencing space weather and all.

[00:10:56] Jacinta: Space weather. That’s a cool concept. Is that what causes the aurora that we see?

[00:11:01] Priscilla: Oh yeah. When tsese energetic particles get into that atmosphere, then they interact with molecules. And usually that is at the poles because we know that the magnetic field is polar. So, at the poles, at the north and the south poles, we get to experience the aurora.

[00:11:20] Jacinta: Okay, great. So it’s, at high energy particles from the Sun, released through coronal mass ejections.

Streaming through space to the Earth where it causes space , they interact with the Earth’s magnetic field, spiral towards the poles and cause these beautiful green light shows for us.

[00:11:37] Priscilla: Northern lights and..,

[00:11:38] Jacinta: Yeah.

[00:11:39] Priscilla: Yeah. Very beautiful features.

[00:11:40] Jacinta: Yeah. So I guess it’s our atmosphere, and it’s our magnetic field that is kind of protecting us from the impact of these high energy particles from the Sun. What would the impact of this kind of star activity have on planets around other stars?

[00:11:57] Priscilla: Yeah. So, for M stars, because they’re very active… If a planet has to be safe, we would need a very strong magnetic field that will deflect these particles as they come towards the planet. But it so happens that most of these planets are..,

First of all at a short orbital distance from the star. So most times they are tidally locked. So, they cannot generate a sufficient magnetic field. So, which means that when particles are streamed from the star, they will actually interact directly with atmospheres of these planets.

[00:12:36] Jacinta: Oh, right. By tidally locked, you mean that the planet is always facing the same side to the star?

[00:12:41] Priscilla: Yes, that’s right.

[00:12:42] Jacinta: And you said that, that means it doesn’t have a magnetic field.

[00:12:45] Priscilla: It cannot generate a strong magnetic field, because you see magnetic field also is influenced by the rotation. And also if it’s always tidally locked, there’s going to be a very small magnetic field.

[00:13:01] Jacinta: Okay. So you said that it doesn’t have a magnetic field, so there’s nothing to protect the planet from the..,

[00:13:07] Priscilla: It does have, but it has a small magnetic field,

[00:13:10] Jacinta: Right. Sorry.

[00:13:11] Priscilla: Oh, sometimes it is close to zero, depending on the structure of the planet. But, we would need a very big magnetic field, because these planets are very close to their hostess. So, which means that the interaction is very big. So, we need a very big magnetic field if it’s to deflect away these particles from reaching the planetary surfaces.

[00:13:36] Jacinta: Okay. So the there’s a weak magnetic field, not strong enough to stop the particles. The particles hit the atmosphere and then what happens?

[00:13:44] Priscilla: So when the particles hit the atmosphere, they get to interact with the molecules in the atmosphere, and most of these molecules are hydrogen. So, what happens is that there will be escape of the hydrogen, and eventually the atmospheres will be lost.

And of course we know just like for the Earth, if we didn’t have an atmosphere, we wouldn’t actually be existing, because that atmosphere keeps us safe from ultraviolet radiation, which would otherwise kill all the life cells. Yeah. So it’s very important to know how much radiation comes to this planet if we are going to think of looking for a habitable planet.

[00:14:24] Jacinta: So the activity of the star might result in the, essentially the evaporation of the atmospheres of these planets. And I guess that, that’s important to know isn’t it? If we’re trying to search for life out there in?

[00:14:37] Priscilla: It’s very important because without an atmosphere, life cannot be sustained. It’s actually the same as on Earth. Of course when a star is young, the activity is usually high. As it grows, the activity tends to reduce.

So, probably for the Earth, in the beginning it also had a hydrogen atmosphere. And because of the high activity of the young Sun, some was eroded until we got to form a secondary atmosphere which we are now living under. So, similarly you find most of the M stars are young, middle age, old. So for the young stars, we need to understand, does the evolution of the atmospheres also take on the same trackers?

What happened for the Earth? Because when they’re young, it means they’re very, very active. So if we’re able to establish the activity rate when they’re young, it’s very easy to predict what will happen as they grow. So it’s very, very important.

[00:15:39] Jacinta: So, what do you do in your work? How do you study these M stars and the influence they have on their planets?

[00:15:45] Priscilla: Yeah, so we do observations of the M stars. Currently, we are looking at ED Leo and EV Lac. These are very young and active M stars; bright enough for where we are doing the observations so we can be able to observe them. And we do high resolution spectroscopy. We study the behavior of the chromospheric lines.

chromospheric lines, are lines.., emission lines that are produced due to absorption of light in the outer layers of the star. So these lines can give us a hint on material that is moving in the chromosphere; in that part of the chromosphere, because basically we are trained to look for flares and CMEs, and trying to see how their effect influences atmospheres of planets around such M stars.

So you look out for extra emission in a chromospheric lines, and of interest. We have Hα, Hβ, and helium one lane. Which only exists when the chromosphere is very hot, it only exists at very high temperature. So they are good indicators for stellar activity.

[00:17:00] Jacinta: So the chromosphere is part of the atmosphere. Is that right?

[00:17:03] Priscilla: Yes. Of a star.

[00:17:05] Jacinta: And what telescopes do you use for these?

[00:17:07] Priscilla: We’re using the Totenberg day shell telescope in Germany. That’s where we are doing observations from.

[00:17:15] Jacinta: What kind of a telescope is that?

[00:17:18] Priscilla: It’s an optical telescope.

[00:17:19] Jacinta: So it’s an optical telescope with a spectrograph?

[00:17:22] Priscilla: Yeah. Yeah.

[00:17:22] Jacinta: I’m assuming, which is helping you to figure out which of these molecules and atoms are in the atmospheres of these stars.

[00:17:28] Priscilla: Yes, yes.

[00:17:29] Jacinta: Great. And how do you apply for time on this telescope?

[00:17:33] Priscilla: Currently, we have a collaboration with the institute that host the telescope. So, we were given observing time every month when the object is visible, for a week. So we do observations for one week, every month when the object is visible.

[00:17:49] Jacinta: And what have you found so far?

[00:17:51] Priscilla: So far? Several flares, but still not trace of a CME. So we are still searching for a CME because our motivation in this study is, previous studies aimed at looking at predicting the possible CME rate on these very active stars. But they were using solar relationships because the Sun is easy to study, cause it’s the nearest, these are the stars look like point objects to us. So, there’s so much information we can get from the Sun. And there’s been an established flare CME relation for the Sun. Using the flare rate, you can determine what the CME rate would be. And so, previous studies looked at how they aimed at using that same relationship, to predict what happens on these M stars.

But we’re asking how credible is that, because you are comparing two stars with different activity rates. So it could be possible that a high flare rate may imply a high CME rate, but also at the same time, you may have a high flare rate with no CMEs. And so far, we’ve not found a CME.

We are still hoping to see one, because it’s not that they’ve not been observed on this particular star ED Leo. A very big CME was observed about 29 years ago, and that was the only CME so far that was observed. All the other studies have not come up with something really good to prove that actually this is a CME. There’s always material living, but with a very small velocity, that does not qualify to be a CME.

So, we set out to find out, if we have a longer observation time, can we be able to get these CMEs? Are they rare? Or are they never there? That’s also another thing. And then, from there we can know, is it really right that we use the solar relationships? So, probably we need to actually get the CMEs from these test, and then we can come up with models to predict how frequent they occur. And if they don’t occur, then we also see what next.

[00:20:09] Jacinta: Great. So, I mean, good luck with your, the rest of your research. This sounds..,

[00:20:14] Priscilla: Thank you. Thank you. Thank you.

[00:20:15] Jacinta: Really interesting, and I am really interested in hearing what your result is.

[00:20:19] Priscilla: Yeah. Yeah.

[00:20:19] Jacinta: Do you have any other messages you’d like to share with our listeners?

[00:20:22] Priscilla: I advocate for women in science. I like to see more women in science. Wherever your best, whether in a developed country, or a developing country, and in underdeveloped country, I don’t care, but I wish to see more women represented in the scientific community, and especially astronomy.

Currently, we try to do runs and drives to see that we encourage more girls and women into science and STEM fields, and I hope that it can yield something in the next five years.

[00:20:59] Jacinta: I agree. And it’s quite great that we have role models like yourself to follow.

[00:21:03] Priscilla: Oh yeah.

[00:21:04] Jacinta: So good luck with the rest of your PhD. And we’re all cheering for you, and maybe we can speak to you again one day when find out what your results are.

[00:21:12] Priscilla: Oh, thank you. It will be a pleasure.

[00:21:15] Jacinta: Thank you very much for talking with us today.

[00:21:17] Priscilla: You’re welcome.

[00:21:25] Dan: Great. Thank you for that. I mean, for me, studying stars has always been quite, I don’t know, it’s out of my field. I’ve always been focused on galaxies and much larger things. Realizing how much there’s still to learn about how stars are kind of behaving and they’re very vibrant. Yeah..,

And they’re not

[00:21:45] Jacinta: so peaceful.

[00:21:46] Dan: No, they’re really not. And, yeah, it’s quite cool. And I think the relation to the exoplanets is really, really nice too. There’s a lot of interest in the exoplanets these days. And, trying to understand what sort of stars host these exoplanets, and what sort of exoplanets will be orbiting around what stars is this. Kind of a new, sort of era of astronomy.

[00:22:06] Jacinta: New field, really.

[00:22:07] Dan: Yeah. It is kind of a new field. Yeah.

[00:22:08] Jacinta: These planets are, as Priscilla said, tidally locked to their host star, and they don’t have strong magnetic fields, so they don’t have atmospheres, or magnetic spheres that are protecting the surface of the planet from these flares, or coronal mass ejections from the star.

And I guess just one flare, or one coronal mass ejection could just wipe out any life that had started to form on that planet. So, these must be really harsh conditions for life to try and start forming.

[00:22:35] Dan: You keep realizing how incredibly lucky we are?

[00:22:39] Jacinta: Lucky. Definitely.

[00:22:42] Dan: And, also just great to hear the work she’s doing in Uganda, right?

[00:22:46] Jacinta: Yeah. And I absolutely agree with her about, encouraging more women in astronomy everywhere in the world, but particularly also in developing countries, such as Uganda and other African countries.

[00:22:58] Dan: Yeah. Wonderful role model.

[00:22:59] Jacinta: Definitely.

[00:23:01] Dan: And, next up we have Hakeem Oluseyi, who joined us to talk about some of his work, and also talking about stars and coronal mass ejections.

Some of the work he’s done on the Sun, and how it’s.., it affects the Earth. But then also how these stars.., The state of pulsations can be used to measure distances to distance stars. And then, I mean, that was a great step forward in astronomy when that was first discovered.

[00:23:29] Jacinta: Yeah. As Hakeem explains, this was really groundbreaking for the field of astronomy; and our understanding of our place in the universe.

[00:23:37] Dan: Yeah, absolutely.

[00:23:39] Jacinta: So let’s hear from Hakeem.

In the studio with us today is, Distinguished Professor Hakeem Oluseyi. Hi Hakeem.

[00:23:53] Hakeem: Hello, how are you?

[00:23:55] Dan: Hello! Good. Thank you.

[00:23:56] Hakeem: Also, thanks for having me.

[00:23:59] Dan: I wasn’t ready for that.

[00:24:00] Hakeem: Ahh.., Daniel.

 What’s up man?

[00:24:01] Dan: Flipping it to me.

[00:24:03] Hakeem: Yeah.

[00:24:04] Dan: So, Hakeem, thank you for joining us. And, can you tell us quickly who you are, and where you from?

[00:24:09] Hakeem: Well, as you already heard, my name is Hakeem Oluseyi. I’m based in the United States of America. And, I’m a Professor at the Florida Institute of Technology.

[00:24:19] Dan: And what do you do there? Research wise?

[00:24:21] Hakeem: Yeah. So my.., I’m weird because I’ve read many years ago that a researcher follows their curiosity, and that’s what I do. So I don’t do one thing like many researchers do.

So, one of the things that I do is study the surface of the Sun, the atmosphere of the Sun known as the Corona. And, another thing that I do is study our galaxy using what’s known as survey science, where we map out the sky and discover millions of stars, or observe millions of stars. And, we get basically a movie of the sky.

And from there, we can tell a lot of things about different types of stars, and the stars that I’m interested in are the ones that change their brightness by pulsating.

[00:25:03] Dan: Okay. So, tho those are two quite different astronomical techniques. So, if we’re looking at the Corona of the Sun, what sort of telescopes are you using for that?

And, do you have telescopes here in South Africa that you’ve used in the past or?

Yeah.

[00:25:16] Hakeem: So, the work on the Sun is using a technology that I helped to develop in graduate school. So when you see these pictures of the Corona with all the pretty plasma loops, the type of mirror that takes that image, is not the same kind of mirror that you look at in the morning and get ready for for your day.

This mirror we’ll reflect invisible light. Like what do we call soft x-rays, or what we call extreme ultraviolet light. And so, it has to be built up layer by layer in a very special way. And what it allows us to do is take a photograph of the Sun at a particular temperature. So, when you look at the images that come down from space, you have images that are at a million degrees, 1.5 million degrees, 20,000 degrees.

And so, you fit all this stuff together, along with measuring the magnetic fields at the surface of the Sun, and kind of figure out what’s happening. And that’s what we do. We take the light and we interpret it, and it tells us what the matter is doing on the Sun, and what the fields are doing.

[00:26:14] Jacinta: And what are they doing?

[00:26:15] Hakeem: They are busy. They’re moving around. The surface of the Sun is boiling. It’s like it’s covered in a big giant ocean of 6,000 degree plasma. And these magnetic fields that are created inside the Sun are buoyant. They flow up to the surface, and then they break up from the surface, and now they control what the mass and plasma do.

And so, many people are familiar with solar flares. That’s when you have large magnetic regions, doing what we call reconnecting the magnetic fields break, reconnect to others, and they give all this energy to the plasma, which comes to us as light. And sometimes it comes to us as a big blast of matter of stuff that gets sent out of the Sun.

And we call that a coronal mass ejection.

[00:26:58] Dan: Just in terms of the telescope again. These telescopes, we can’t see, UV and x-ray from, from Earth, correct?

[00:27:06] Hakeem: We cannot see it from the ground. It can’t make it through our atmosphere. Now, you can measure magnetic fields from the ground, but it turns out that we do it so much better from space, that the ones in space are the ones that we actually use the data for.

So anybody, if you’re in South Africa and you wanna study the Sun, the data that comes down from these satellites is freely available for anyone to use.

[00:27:27] Dan: All right. And that’s stuff you use. So, there’s these telescopes sitting up there observing the Sun all the time.

[00:27:31] Hakeem: That’s right.

[00:27:32] Dan: With these special mirrors to detect.

[00:27:33] Hakeem: Yep.

[00:27:34] Dan: Oh, excellent.

[00:27:34] Hakeem: Yeah.

[00:27:35] Dan: And then to do that research, you said these coronal mass ejections come, and everybody talks about sort of flares and it’s quite a dangerous sort of, I don’t know, there’s a lot of fear and,

[00:27:45] Hakeem: yeah,

[00:27:45] Dan: I guess misunderstanding about what these things do to us. What do they do? And what do they look like for a telescope, firstly, and then when they hit Earth?

[00:27:55] Hakeem: Yeah. So, you know, it’s really crazy, but the first solar flare to be observed was observed with the naked eye. And so the observer, I forget exactly who it was in history, actually drew a picture of this bright spot on the Sun. Now we know you’re not supposed to look at the Sun,

[00:28:09] Jacinta: mm-hmm…

[00:28:09] Hakeem: Without, you know, having some approved solar glasses on, right? To protect your eyes, because the light that comes from the Sun will damage your eye, if you look at it. But in the old days they did that. Right? And now, what kind of damage they can cause? If you are inin space, it can be some serious damage, right? It’s radiation from the Sun. It’s protons primarily that are flying down.

And so they often affect the instruments that we use in space. It, they, you know, the electronics can get affected by this radiation. But it also interacts with the Earth’s atmosphere. So, you’ve heard of the ozone layer. The ozone layer is created by the light from this part of the Sun. And when the Sun gets more active, as we say, Earth’s atmosphere swells.

And that means that, the satellites that are in low Earth orbit, which is most of them, they experience more drag and they can like deorbit and come back down to Earth. But what’s happening right now, is our son is way less active than normal. And so when this happened centuries ago, it was a period known as the Maunder Minimum.

There were, you know, famines that occurred in association. Now we don’t, we can’t say with scientific certainty that the solar activity caused the famines, but the fact that they correlated suggests that. And so now we’re going into another cycle like that, potentially. We don’t know if that’s the case, but what we do is we count the number of Sun spots on the Sun’s surface.

And if you look at, the last several cycles, so the Sun is more active on a cycle of 11 years. And so if you, the number of Sun spots every 11 years is getting smaller and smaller. Right? And so it may go to zero. And if it stays there for a long time, then the Earth’s atmosphere is gonna settle way down. It’s gonna contract way down, and weather may change as a result.

[00:30:05] Dan: Whoa!

[00:30:07] Hakeem: Yeah.

[00:30:08] Dan: Man, I didn’t know that. Like, I mean, I knew about the 11 year cycle. I didn’t realize that this was something which was slowing down. Do we have a better understanding than we did a hundred years ago about why this happens?

[00:30:20] Hakeem: Not really. So it’s all about the process that makes magnetic fields on the Sun, and we call that the solar dynamo; whatever it is that creates these fields. Now I told you that the Sun is like it’s covered in a boiling ocean of hot plasma. Well, that’s the outer one third of the Sun, and the magnetic fields, what we know is they’re created where that layer interfaces with the layer below, but the exact process we don’t understand. And something’s very similar is happening with the Earth right now. So the Earth’s field, north pole has been, in New Finland Canada for the entire human history. And now it’s moving at 40 miles per year toward Russia.

So we think that the Earth’s pole is flipping. Right? The north pole will become the south, and the south become the north. And so the thing about Earth is, you know, we’re very lucky here because we have a very thin atmosphere, but also we have a strong magnetic field that protects us from the radiation from the Sun and beyond.

So when the Earth flips its pole, which the Sun does 11 years. Then we might have a period of being not very well protected, from this type of radiation. So, when you’re like in an airplane, you get more radiation than when you’re in a ground. So, will it become dangerous? Right? That’s the question that we have? Will it become dangerous if you’re up there a lot as a pilot?

That’s another question that we have. So, another thing that happens though, is that when the activity from the Sun strikes the Earth’s magnetic field, it can cause the Earth’s magnetic field to change. And a changing magnetic field through a process, we call induction, creates electric fields. And so that means that, when one of these big flares of coronal mass ejections, caused the Earth’s magnetic field to rearrange. That causes huge currents to go through the power lines that we use.

And so back in 1989, it wiped out the electricity in north America for a huge portion of it in Canada, and America’s Eastern area.

[00:32:13] Dan: We’re quite used to that in South Africa.

[00:32:17] Jacinta: Yeah. We have load shedding. Just going back a minute, what actually causes the Earth’s magnetic poles to flip?

[00:32:27] Hakeem: Right. So, is exact same type of problem we have with the Sun, which is figuring out what’s the source of the Earth’s magnetic field. So on the Sun, we know it’s the interface between this outer layer and the next layer in. On Earth, we know it has to do with the nature of Earth’s core. It has a liquid core and a solid core. And, whenever you have currents, whenever you have charged particles like electrons, like we use electricity every day. And what’s happening there, is electrons are flowing. Whenever these charged particles flow, they create magnetic fields.

So if you have the flow of liquid metal inside the Earth’s core, then that’s gonna create magnetic fields. And if it’s, the direction is.., So you can imagine that it’s spinning in one direction. If it changes the direction that it’s spinning, right? Then that’s gonna change the direction at the magnetic field point.

[00:33:17] Dan: Yeah, but as you said, it’s first gonna slow down at some point.

[00:33:20] Hakeem: Yeah.

[00:33:20] Dan: And that’s gonna weaken the magnetic field and that’s where it gets a bit dicey.

[00:33:24] Hakeem: Yeah. That’s where it gets dicey. And we don’t, you know, we don’t know, we don’t know. I imagine it like, suppose there’s a species that lives in your toilet, and they only last a generation only lasts one second. Right? Then over the course of a day, you’ll have many, many generations. Right? And so they may think that the normal state is the toilets just sitting there still, but then someone comes alongs and flushes the toilet and they’re like, ohh.., freak out.

[00:33:48] Dan: I mean, I wasn’t thinking about the flush. Okay. Yeah. I mean,

[00:33:52] Hakeem: but we have a sense of normal. It’s my idea. But humans, our life cycle is so short compared to the lifespan of..,

[00:33:59] Dan: No, for sure.

[00:34:00] Hakeem: The timescale of these changes,

[00:34:01] Dan: It’s an interesting analogy though.

[00:34:02] Hakeem: Yeah, I know it, it is not the best analogy. Maybe actually come up with one that does it involve a toilet? I don’t know.

[00:34:07] Dan: It’s yeah.

[00:34:08] Hakeem: Maybe it’s your cup of coffee.

[00:34:09] Dan: It’s definitely descriptive. gets you your attention.

[00:34:13] Jacinta: Since we was talking about toilets, let’s let’s change the subject a little. You said your second topic is on pulsating stars.

[00:34:19] Hakeem: Yes. Yeah.

[00:34:20] Jacinta: What are pulsating stars?

[00:34:22] Hakeem: Yeah. So there are these stars that are old, and what happens is something very similar to when you boil water. If you take a pot of water and you put it on a fire, and you put a thermometer in there, what you see is that the more energy you put in there through the heat of the fire, the hotter and hotter the water gets. But then once the water starts boiling, it doesn’t get any hotter, even though you’re adding energy.

And the reason why, is because instead of that energy, going into making a water molecules, move and vibrate faster, which we call heat, it breaks them apart, right? It breaks apart the liquid phase into the gas phase. And so that phase change is what eats up that energy. And so, the same thing happens in these stars.

There’s a layer where there are helium atoms, and instead of the energy flowing out of the star, the energy is absorbed by these helium atoms, and one electron is removed from them. And so now, a star, or anything that’s like a gas like, or plasma like, if you heat it, it expands. So, since this energy is staying in, in order to ionize this helium, instead of escaping, the star gets hotter and it expands. But eventually, as it gets bigger, it’s cooling at the surface.

And so eventually it gets so cool, that now the helium atoms can capture those electrons again. And suddenly, it is not absorbing energy, and so it falls back down to its small state. So it expands slowly and then falls back down to the small state; expands slowly falls back down to the small state. And surprisingly, they’re brightest when they’re in their smaller state and dimmer when they’re in their larger state. And that’s because they’re hotter when they’re smaller. And the thing about these stars is, we can tell how far away they are based on how they pulsate. We know what type of star it is, and then we can tell how bright it really is.

And so if you compare how bright something really is to how bright it appears to be, you could tell how far away it is. Much like if I gave you a flashlight or a lantern, and told you to go stand in the field. If I know how bright your lantern is really based on how bright it appears, cuz it gets dimmer as you move farther away, I could tell you how far away it is.

So in astronomy, the most difficult problem, is the problem of measuring distances. All stars look the same through a telescope. Doesn’t matter if they’re near or far. A far away big, bright star, will look identical to a nearby small dim star. So how do you tell what you’re looking at? Is it big, and bright, and far away? Or small, and dim, and close? Right? So with these types of pulsating stars, we can measure their distance. And then that allows us to do a lot of different things.

[00:37:04] Dan: So these pulsating stars that we use for, to calibrate distance, therefore a particular range of distances. Okay.

[00:37:11] Hakeem: Right.

[00:37:12] Dan: So, nearby we can use parallax.

[00:37:14] Hakeem: Yep.

[00:37:14] Dan: So we can just see the sort of shift on,

[00:37:16] Hakeem: Yeah.

[00:37:16] Dan: On a yearly basis, of the positions of the stars. But once they get further away and then other galaxies, it’s impossible to take those differences.

[00:37:26] Hakeem: Right.

[00:37:26] Dan: How far out can we measure distance using pulsating stars? Because presumably at some point you can no longer pick up individual stars.

[00:37:35] Hakeem: Right. Right. And that’s an amazing question, because this is what Edwin Hubble did to prove that what they were called in, at the time, Spiral Nebulae, which we now call galaxies, were actually outside our galaxy.

So, he saw them in the Andromeda galaxy, which is around 2 million light years away. Right? And so with Hubble, you can look very deep in the space and find these stars, millions of light years away. I use smaller telescopes to do it. So I find stars that are around our galaxy, that surround our galaxy, and what’s known as the halo in the attempt to find satellite galaxies of our galaxy; because we are trying to understand how do galaxies build up.

And also, the incoming stuff. What is it made of? Is it made of the same stuff that’s already here or, you know, cause what happens is, stars change what the matter is, right? So hydrogen becomes helium, helium becomes carbon and oxygen inside of stars. And, like when we saw two neutron stars collide a year or so ago, you know, 10 times the mass of the Earth, and gold was created in that collision.

S, you know, it’s really fascinating stuff and, you know, if you have a bigger telescope that can capture more light, then you can see farther and farther into the universe.

[00:38:54] Dan: Yeah, for sure. I mean.., I’ve got lots of questions. So the Milky Way, you’re looking at, looking for satellite galaxies. We know there are two satellite galaxies, the Small Magellanic Cloud and the Large Magellanic Cloud. And then the Southern hemisphere, we are fortunate enough to be able to observe those with the naked eye even. Is there evidence for more?

[00:39:12] Hakeem: Oh yeah. So one of the most famous ones is called the Sagittarius Dwarf, which is actually colliding with our galaxy. Our galaxy is eating it. And so, as it’s orbit in the Milky Way,

it gets torn apart gravitationally by tidal forces. So there’s also what is known as the Sagittarian Stream. And these little galaxies, when they come in, you know, they end up getting incorporated into our galaxy and becoming a part of it. And so, there are several streams. There’s the Monoceros stream. So, you know, 20 years ago we knew about the.., You know, large and small clouds of Magellan, we knew about the Sagittarius stream. But then, you know, the predictions are that there should be about 200 of these dwarf galaxies. And we only knew about, you know, 4 or 5 as of 20 years ago. Now we know of around 30. Right? So we’re finding them.

[00:40:01] Dan: But they’re all like streams now. They’re all getting stripped out like,

[00:40:04] Hakeem: Yeah, some of them aren’t stripped apart yet, and they’re just like clumps, but they’re just not bright like the, what you can see here. Like the Southern hemisphere sky is so amazing. It so beats the Northern hemisphere sky, I tell you. Yeah,

[00:40:17] Dan: No, I know.

[00:40:18] Jacinta: He definitely does.

[00:40:21] Hakeem: Yeah. I love coming down here for exactly that reason.

[00:40:24] Jacinta: Speaking of which, why are you here at the moment? What are you doing in South Africa?

[00:40:28] Hakeem: Yeah, so we are here working on forming the first continent-wide organization of astronomy professionals on Africa, known as the African Astronomical Society. We initially formed the African Astronomical Society in 2011. And then, over time, things kind of dissolved. And so now it’s reformed because the astronomy community today is not what it was back then. South Africa, for example, has done a great job of helping to create astronomers, not just in South Africa, but around the African continent.

And so, they come here to do their astronomy. You have the MeerKAT array, you have the SALT telescope, you have other telescopes out of Sutherland. And, you know, the African skies are dark and they’re in the Southern hemisphere, many of them. And so, those are the skies we need to make observations from. Right? So, what we’re doing is in service, not just to Africa, but in service to the world.

[00:41:28] Dan: The growth of astronomy in South Africa, as you mentioned and training students, that’s largely been done through the NASSP program,

[00:41:35] Hakeem: Right.

[00:41:35] Dan: The National Astrophysics and Space Science Program. And you’ve been involved in that. Can you tell us a little bit about it?

[00:41:40] Hakeem: Right. So my colleague, Charles Mcgruder, he got a grant from the Kellogg foundation. We did through an organization in America, known as the National Society of Black Physicists. So, in America, I was the one black astrophysicist who had grown up in underprivileged circumstances. Right? And so, Charles asked me to join with him in this program. And he said to me, Hakeem, you know, as well as I, that the problem is not a problem of academics. Right? And so, I came here and I worked with NASSP students, and so what was happening up to this time, when I started in 2008, is South Africa only produced three black astronomers.

And all of them were in a year, 2003. And there was a phenomenon where students would get recruited, but you know, they’d come to UCT, and they would have a difficult time passing what’s known as the honors exam. And so, after working with students for three years, myself, Charles Magruder and others, my Professor host at University of Cape Town, Peter Dunsby said to me, he said, Hakeem, I have great news for you. Not only have all the students you worked with passed their honors exams, they all passed in the top 20%. Right? So that was very exciting. And shortly after that, I traveled internationally, and they would talk about the SKA contest and South Africa.

And they would show the SKA control room, and I’d see my students there. Right? And so that was the greatest feeling in the world, knowing that you could contribute to helping people change their lives. Cuz even in my own community, you know, my father dropped out of school when he was 9 years old, and my mother dropped out of school when she was 16.

So I had no idea that something as astronomy, as a career existed, or physics as a career existed. People reached out to me, and that’s how I learned about it. So, I thought the least I can do is reach out to others. But, when you change one person like myself, you changed your whole community. Because now the people in my old community where nobody went to the university now, you know, have the kids go to the university.

[00:43:35] Jacinta: Yeah. Now the NAASP program has produced, I think, over 150 Masters, and 90 PhDs.

[00:43:41] Hakeem: Wow!

[00:43:41] Jacinta: Which is a huge number.

[00:43:43] Hakeem: That is a huge number.

[00:43:43] Dan: Yeah. That’s in less than 15 years, I think.

[00:43:46] Hakeem: Wow! That’s incredible.

[00:43:48] Dan: Yeah, amazing stuff.

[00:43:49] Hakeem: Yeah. Yeah. Yeah. Well, the astronomy community in South Africa is worldwide, top class, right? It’s not just, you know, top class on a continent of Africa. It’s top class worldwide. And of course it comes down to your assets, and your main assets are your people .

[00:44:11] Dan: And I mean, that’s absolutely true and tat we.., there’s a great bunch of astronomers in the African continent. And as you say, now forming into the African Astronomical Society to hopefully cement that relationship and move this forward.

[00:44:25] Hakeem: Yeah. Yes. There’s still many countries in Africa where there are no astronomers. Some, I heard an estimate yesterday, there’s 34 from which there are, you know, no astronomers. And even if you look at major observatories for a while, in terms of working observatories, it was only South Africa. But now of course, Ethiopia’s had a working large meter class telescope for quite a while. There’s one being built in Burkina Faso. I think, Egypt has one. And of course there are non-visible, like telescopes in places like Namibia.

[00:44:53] Dan: Yeah.

[00:44:53] Hakeem: Yeah.

[00:44:54] Jacinta: Well, this has been absolutely wonderful, Hakeem. Do you have any other final messages for our listeners?

[00:44:59] Hakeem: Well, I would like to thank all of the people of South Africa for being so amazing, and allowing me to come visit, and contribute to developing your community and being a part of it. It is one of the highlights of my career in life.

[00:45:12] Dan: Thank you. Thank you for your contributions, and thank you for your passion. And,

[00:45:17] Hakeem: Thank you.

[00:45:17] Dan: And thank you for these.

[00:45:18] Hakeem: Anytime.

[00:45:19] Jacinta: Thanks for chatting with us.

[00:45:20] Hakeem: Bye bye.

[00:45:28] Jacinta: Wow. That was an awesome interview. So many things, I don’t know where to start. I guess I just, I found it fascinating to hear how living next to a star, the Sun, which gives us our energy and light, can also cause absolute havoc.

[00:45:43] Dan: Yeah. So scary concepts.

[00:45:45] Jacinta: Yeah. I mean, It could have caused famines on the Earth.

[00:45:47] Dan: Well, at the very least, I mean, I think that, yeah. We don’t realize how vibrant, and sort of unpredictable these things are. And talking about that cycle, the sort of the fact that the Suns 11 year cycle, which we kind of thought we knew about, is dissipating now, and the fact that that’s gonna have and… I always knew that the magnetic fields were weakening, and maybe were gonna flip, and things like that.

[00:46:10] Jacinta: On the Earth,

[00:46:11] Dan: on the Earth.

[00:46:11] Jacinta: Yeah.

[00:46:12] Dan: But like, the fact that the Sun’s activity can affect our atmosphere, and the thickness of our atmosphere, sort of puffing up our atmosphere.

[00:46:20] Jacinta: Yeah. He said that the activity of the Sun actually creates the Ozone.

[00:46:24] Dan: Yeah. I guess it’s the energy is required to excite those particles. And again, we’re, we always knew we were heavily dependent on the Sun for all of our energy, and heat, and all of our cycles with the cycles and everything else, but realizing that the Sun’s not quite as stable as we previously thought. And,

[00:46:44] Jacinta: And the actual fact of that instability, which helps us have an ozone. I mean, it’s all tied together so intricately and again, just how lucky we are.

[00:46:52] Dan: Yeah. And that we’ve been lucky for four and a half billion years.

[00:46:54] Jacinta: Exactly.

[00:46:55] Dan: I guess we’ll just hold on for a little bit longer.

[00:47:00] Jacinta: Fingers crossed. Huh?

[00:47:01] Dan: I like still getting right up now. Isn’t it?

[00:47:04] Jacinta: No, we’ve got a few million years, I think probably two…

[00:47:08] Dan: Million? Maybe a few billion,

[00:47:09] Jacinta: Few billion to figure out what to do about it.

[00:47:12] Dan: Yeah. Wow.

[00:47:14] Jacinta: And, Hakeem also mentioned the NAASP program and the graduates. So, I’d also like to take this chance to congratulate the latest graduates who came through the program, and have been recently awarded their PhDs from the University of Cape Town.

And that was to Dr. Sam Legodi, Dr. Kerry Paterson, Dr. Elizabeth Naluminsa, Dr. Marie Korsaga, and Dr. Brenda Namumba. Now Marie actually becomes the first female astrophysicist from the country of Burkina Faso.

[00:47:45] Dan: Brilliant.

[00:47:46] Jacinta: Yeah. And, Brenda becomes the first female, Zambian physicist. So first PhD in any physics field.

[00:47:55] Dan: Glad she chose astrophysics.

[00:47:56] Jacinta: Yeah. And Zambia’s very first PhD in astrophysics. And Liz becomes the first Uganda woman to earn a PhD in astrophysics. So she may have just picked Priscilla at the post there, but, Priscilla may still become the first to earn the PhD in Uganda.

[00:48:13] Dan: Awesome.

[00:48:13] Jacinta: Isn’t it incredible?

[00:48:14] Dan: Great. I mean, yeah.

[00:48:15] Jacinta: Congratulations to everyone…

[00:48:17] Dan: Yeah, absolutely. Congratulations guys. Must have been very nice for them to hear their names with the doctor in front too.

[00:48:22] Jacinta: Yeah. I mean, I remember when I graduated from my PhD, that was the first moment that was,

[00:48:26] Dan: Yeah.

[00:48:26] Jacinta: That was pretty awesome.

[00:48:27] Dan: Yeah. Walk into the bank.

[00:48:30] Jacinta: Yeah. Are you Miss or Mrs? Uh, Doctor.

[00:48:37] Dan: Yeah. I.., Keep up the great work, everyone. Astronomy and the kind of knowledge economy in Africa and South Africa is growing every day. And again, as Hakeem had mentioned with the development of the African Astronomical Society; Africa’s gonna have a major role to play in the next few decades.

[00:48:54] Jacinta: Absolutely. It will.

[00:48:56] Dan: And that’s it for today. Thanks very much for listening and we hope you’ll join us again on the next episode of The Cosmic Savannah.

[00:49:02] Jacinta: You can visit our website, thecosmicsavannah.com, where we’ll have links related to today’s episode. You can also follow us on Twitter, Facebook, and Instagram, where we’ll post extra pictures, videos, and some behind-the-scene footage.

We’re @cosmicsavannah. That’s Savannah spelled S A V A N N A H.

[00:49:22] Dan: Special thanks today to Priscilla Muheki, and Distinguished Professor Hakeem Oluseyi for speaking with us.

[00:49:29] Jacinta: Thanks to Mark Allnut for music production, Janus Brink for the astrophotography, Lana Sarae for graphic design, Michal Lyczek, for photography and assistance, and Sebastian Tulinski Obrocki for help in post production.

[00:49:42] Dan: We gratefully acknowledge to the support of the South African National Research Foundation, and the South African Astronomical Observatory to help keep the podcast running.

[00:49:50] Jacinta: You can subscribe on Apple podcasts, Spotify, or wherever you get your podcasts.

[00:49:54] Dan: And we’ll speak to you next time on The Cosmic Savannah.

Great. So, let’s hear from Priscilla,

[00:50:05] Jacinta: blah, blah, blah, blah, blow, blow, blow, blah, blah.

Okay. In the studio with us today is Hakeem Oluseyi.

[00:50:12] Hakeem: That’s the best anyone’s ever said my name.

[00:50:14] Jacinta: Oh, really?

[00:50:15] Hakeem: Yeah.

[00:50:15] Jacinta: Well, I’m gonna leave it to her.

[00:50:18] Hakeem: uh,

[00:50:20] Dan: Is it? Cause I’m gonna do the guests. Muheki and Hakeem Hakeem Oluseyi. Shay. Yeah.

Yeah. I know you did it. Well, whatever ,

[00:50:30] Jacinta: I’m gonna put that in the bloopers .