New Photos Show Swirling Mysteries On Sun’s Surface

IRA FLATOW: This is Science Friday. I’m Ira Flatow. With summer here most of the news about our home star, the Sun, most likely will involve sunscreen. And that’s something we should all be paying attention to.

But scientists are also paying close attention to the surface of the Sun. Because despite it being so ever present, we still have a lot to learn about the Sun. And they have just announced that the Solar Orbiter– a satellite orbiting the sun– has just sent back some photos of surprising events on the Sun’s surface.

Here to talk to us about these new images is Anik de Groof, Instrument Operations Scientist for the Solar Orbiter. She’s based in Madrid, Spain, and joins us today by Skype. Welcome to Science Friday.

ANIK DE GROOF: Hello.

IRA FLATOW: I believe that these are the closest direct images of the Sun’s surface. Is that right?

ANIK DE GROOF: That’s correct indeed. There has never been cameras actually observing the Sun from that close. So we have had satellites go in closer, but never with images– never with telescopes.

IRA FLATOW: So tell us, this being a radio program, when you looked at those images, what was that surprising thing you saw on the surface of the Sun?

ANIK DE GROOF: Well, so first, we were really excited to see these first images, because these are really the very first data we got from the satellite. So it’s even just test images still. But we could already see new features. So what we saw mainly was in the EUV Imager.

So that is a telescope that is looking at the Sun in extreme ultraviolet light. You cannot see that from Earth, because the atmosphere is blocking it, but we can see it from space.

And so there you see part of the atmosphere of the Sun– the solar corona. And that atmosphere is currently very quiet. There is not that much activity on the Sun. But now it turns out, when we were zooming-in, that we see very little eruptions– which are much, much smaller than the ones we can usually see. And so this was quite a surprise, because we have never seen these features before.

IRA FLATOW: And they were called campfires, if I’m reading this correctly.

ANIK DE GROOF: Yes. Because indeed, they look like these little flashes or flames of light. And actually, they look like the mini, mini brothers of solar flares. And solar flares are much bigger eruptions of radiation from the Sun. And sometimes they also cause clouds of solar plasma– so solar material that leaves the Sun. And so this seemed to be a micro-flare, so to say. So very-small eruptions.

IRA FLATOW: That’s kind of interesting. Do we know anything about these small eruptions? And how do we study these further?

ANIK DE GROOF: Well, that’s one of the strengths of the Solar Orbiter, that it does not only have these camera. It has many different telescopes– in total six– which will all observe the Sun at different wavelengths. So you see slightly different temperatures from the Sun, and slightly different layers.

So the next bit will be to analyze these new features in all those different types of light, to find out what exactly is happening. And then we also have sensors which are measuring the environment of the spacecraft. And they can see what’s actually coming out of the Sun– so the effects of this little activity on the environment of the Sun, and later also on Earth.

IRA FLATOW: Hmm. So tell me, though, what mysteries you are most interested in finding out more about. What keeps you up at night?

ANIK DE GROOF: Well, one thing that we are really excited about is that Solar Orbiter will also look at the solar poles– so the North Pole and the South Pole of the Sun. And we have never, ever seen these before. We also don’t know whether there is any activity going on there, or how the Sun is structured at its north and south pole.

And this is important to understand how all of this activity works, because the Sun has an activity cycle. So it’s not always as active. It has times– several years– where it’s quite quiet, which is now– the period we are in now. And then we expect, in two-or-three years from now, there will be more solar activity. There will be some what we call solar storms. So this is the time when the Sun is very active.

And then it will go back to a quieter stage. And we don’t really understand how that works. And we think that one of the keys lie with the solar pulse. So that’s the part I’m most excited about.

IRA FLATOW: You know, I never thought about the Sun having poles. I know that the Earth has poles. What creates the poles on the Sun?

ANIK DE GROOF: Well, so when I talk about poles, I talk mainly about the magnetic poles. So the Sun has a magnetic field, like the Earth has magnetic field as well. We have a north pole and a south pole, but on the Sun, it’s all much-more complicated. Because this magnetic field gets completely tangled, and this is actually what causes the activity– and what causes this cycle in activity.

IRA FLATOW: Very interesting. Let me go to some questions from our listeners who’ve tweeted us. Tony asks, “I understand the Sun is warmer on the surface. Is that true? Do we know why?”

ANIK DE GROOF: Yes, it’s slightly different. So the Sun indeed has its own energy source, of course. That is the fusion in the core. So obviously, there it’s super hot.

And then when you move closer to what we call the surface– and the surface is what we see with the naked eye from Earth– then the Sun there has cooled down quite a bit, to about 5,500 degrees Celsius. But then what we see is if you move higher in the atmosphere– and these layers we call photosphere, chromosphere, and then corona– then the Sun is heating-up again.

And so the images we have seen here from this instrument is the part in the solar corona that is at 1-million degrees again. And you even have, in times of activity, even higher temperatures– up to two-or-three-million degrees. And these little campfires we have seen may be part of the explanation of why the corona is so hot. So we think that indeed having these mini-explosions omnipresent in this layer of the solar atmosphere may explain partially why the corona is so much heat– why it’s so much hotter than at the surface.

IRA FLATOW: I find it interesting that we have been around so long, and science has been looking at the Sun so much over hundreds of years, why do we still understand so little about how it works?

ANIK DE GROOF: One of the reasons is that, from Earth, we are a little bit limited in what we can see. So as you know, the Earth’s atmosphere is filtering out some of the light. So we cannot see X-rays, for example, or ultraviolet light of the Sun. And so only when we went into space and we saw the Sun for the first time, with telescopes with special filters, we saw for the first time this atmosphere. Because before we had never seen it– only during eclipses.

So when there is a solar eclipse, most of the visible light of the solar disc is being blinded, because of the Moon that comes in front of it. And only then, suddenly you see this funny layer and these kind of blooms sticking out. And that is the solar corona as well.

So to see it in its full wealth of activity and structure and features, you have to go out in space. And that’s why it has taken us a while to really understand what’s going on there.

IRA FLATOW: Now, we also have another probe. NASA has the Parker Solar Probe, speaking of being in outer space. It’s orbiting the Sun also. How is your orbiter different than the Parker Solar Probe?

ANIK DE GROOF: Well, thank you for that question, because that’s really interesting. Actually, Parker Solar Probe is going much closer even to the Sun than Solar Orbiter, but it does not have any cameras onboard– or at least not cameras that can see straight into the Sun. Because the environment is really too harsh if you go that close.

So on the other hand, Solar Orbiter also has a unique orbit. It is also orbiting quite close, but not so close, but then has the cameras onboard. And so from the beginning, we have been collaborating– the teams behind Solar Probe and the team behind Solar Orbiter. Because it is the combination of the two missions that will really be very exciting for solar physics.

Because we will see the Sun from different angles. Also, the Earth will see it from yet another angle. At times the solar probe will be very close to the Sun, and we will be slightly further out. And we can see actually what’s happening on the Sun while Solar Probe is measuring the solar ring. So it is going to be really exciting to have all the data together.

IRA FLATOW: Well, tell me about a little bit more about the Solar Orbiter. What kinds of data can we collect that we don’t already have? What are the instruments onboard collecting?

ANIK DE GROOF: So you have on one hand the EUV Imager– the one that has these images with the campfires. So this is the solar corona EUV. Then, we also have an instrument that’s looking at even hotter parts of the Sun, where the flares will come from. So that’s an X-ray imager. Then, we also have PHI, which is an instrument looking at the magnetic field on the surface. That will be very important to understand what is causing the activity.

Another instrument, Solar [? HI, ?] is looking at the side of the sun. So not at the Sun directly, but it’s looking at any solar storm or plasma that’s flying out of the Sun.

And then you also have a coronograph. That’s kind of an artificial eclipse [INAUDIBLE], so to say. So it’s also looking at what’s happening around the Sun in the far corner. And so apart from those telescopes, we also have the [INAUDIBLE] sensors– four of them– which are measuring what’s happening around the spacecraft. So they will measure magnetic fields– the different energetic particles that we can measure there, and also any plasma waves that are passing by the spacecraft.

IRA FLATOW: You have a whole bunch of instruments on there. It’s good to see.

ANIK DE GROOF: Yes. It’s a very complete suite.

IRA FLATOW: Yeah. Well, because it’s a once-in-a-lifetime kind of thing, right? You put as many things as you can.

ANIK DE GROOF: Yeah, it’s one of the main goals, actually, of the satellite– to go closer and to make the connection between what we see happening on the Sun and what we measure around the spacecraft.

So that’s why sometimes we want to go close, but we also want to go a little bit further away– because we want to understand what in the end is happening close to the Earth. So we want to see everything in the middle, so to say, and what’s happening there.

IRA FLATOW: Let me get to some of the questions our listeners have been asking about the Sun, in general. For example, Paul on Twitter tweet us, “What happens to the material from a coronal-mass ejection, once it separates from the Sun? Does it burn up? Does it fall back towards the Sun? What’s going on there?”

ANIK DE GROOF: Yeah, so corona mass ejection is when the Sun suddenly loses a lot of material. So typically, you first have a solar flare. And then it could happen that indeed it’s ejecting a lot of material. And then you have a cloud that’s traveling into space.

So sometimes indeed the cloud falls back to the Sun, and then we don’t really call it an coronal-mass ejection yet. So typically, when it propagates into space, it may come close to planets. And then it will affect the magnetic field around the Earth.

So it’s a cloud of energetic particles. You have protons and electrons. And they will interact with the magnetic fields on Earth. And they will cause what we call a geomagnetic storm. So the magnetic field of the Earth may be slightly changed. Also, we see very nice events, like polar lights– both in the North and the South Pole of the Earth. And you could also have disruptions. In case of a very strong storm, you could have disruptions of GPS signals– and even power plants that could be disrupted.

And so the cloud, then, typically– so part of the energetic particles will be captured by the Earth. And then the rest of it may still travel further in the interplanetary medium.

IRA FLATOW: That’s terrific. Let me remind our listeners that I’m Ira Flatow. And this is Science Friday, from WNYC Studios.

And in case you’re just joining us right now, we’re having an interesting talk about the sun with an Anik de Groof, the instrument operations scientist for the Solar Orbiter, based in Madrid, Spain. I understand that COVID-19 caused some setbacks for the Solar Orbiter team. How do you operate an orbiter when everyone is working from home?

ANIK DE GROOF: Well, nobody knew.

IRA FLATOW: [LAUGHS]

ANIK DE GROOF: But indeed, in case of Solar Orbiter, the satellite got launched in February. And then normally, you have the very first week trying to get the spacecraft in the right orbit and testing out the platform. And then you go into the testing of all the different instruments. And this takes, typically, months.

And it’s all very sensitive. Also, it’s all very exciting. So you want to be really with all the teams together to try out all the little steps for your instrument, to look at the telemetry coming back, to check exactly what’s happening– and only then send the next commands to the spacecraft.

So this was completely disrupted by the fact that after a few weeks nobody could travel anymore. There was even a COVID case at the ESA Center, where they do the commanding in Germany. And so in the end, everybody started working through [? telecoms, ?] through webcams– looking at the monitor with all the housekeeping data coming back. And yeah, we made it work somehow.

IRA FLATOW: Just like we’re all doing, right?

ANIK DE GROOF: Yes, indeed. I think it’s the first spacecraft that has been fully commissioned or tested from people’s homes.

IRA FLATOW: That’s a first you never expected to have, right?

ANIK DE GROOF: Oh, indeed. We were not really prepared for that.

IRA FLATOW: That is cool. Let me see if I have room for one more tweet from a listener. Emma, who tweets, “Instead of dumping garbage in the ocean, what if we shot it into the Sun? It just seems like this would be easily incinerated and avoid the issue of drifting through space.”

We get this question so many times on our show. What is your reaction to this? This would be a very expensive way to dump garbage, wouldn’t it?

ANIK DE GROOF: Yes. The problem is it’s not so easy to shoot something straight at the Sun. Even for a spacecraft, it’s not easy to get the spacecraft close to the sun. That’s why, for example, for Solar Orbiter, we need two years to get into an orbit that is coming only almost fourth of the distance between Sun and Earth.

So the problem is, if you shoot something in space, it will start orbiting around the Sun or the planet or whatever. So first you have to already spend a lot of energy and have a strong rocket to escape Earth. And then when you get into an orbit around the Sun, it will just stay there forever. It will not fall into the Sun. That’s the problem.

IRA FLATOW: Yeah, that’s the mythology. Just send it up there and the Sun will suck it right in. I’m glad you fact-checked that.

ANIK DE GROOF: Yeah. Indeed it will not just suck it in. That’s the problem. [LAUGHS]

IRA FLATOW: And the problem is we’ve run out of time. I would like to thank my guest, Anik de Groof, instrument-operations scientist for the Solar Orbiter, based in Madrid, Spain. Stay safe. Thank you for taking time to be with us today.

ANIK DE GROOF: Thank you.

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