Super Solar Storms with Lika Guhathakurta

Introducing the sun and guest Lika Guhathakurta

0:00So, the sun is still at it. But what's it really up to, Neil?

0:05Lika Guhathakurta knows. Yes. Coming up on StarTalk.

0:12Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now.

0:25This is StarTalk. Neil deGrasse Tyson, your personal astrophysicist. Got Chuck Nice with me. Hey, baby. That's right. Your personal ass.

0:36Astrophysicist.

0:40Deal with you later on that one.

0:43So, Chuck, we have a returning guest. Yes. Someone we very much like. One of the all-time favorites. Yes. StarTalk favorite. Yeah. We have Lika Guhathakurta. Yes. I even think I pronounced it right that way. You did it. Right. You did it. Lika, welcome back to StarTalk. Thank you. And it's great to be here and great to have Chuck in the show. What can I say?

1:07Well, thank you, Lika. You're one of the world's experts on the sun. And those who are consuming this via video, you may notice that her hair is as bright as the sun. Yes. Yes. Sunkissed, as they might say. Sunkissed, perhaps. Yes. There it is. Don't go there. Don't go there. So, you're an astrophysicist and the technical name for your subspecialty, I guess, would be heliophysicist. Do we got that right? You got that right.

1:38All right. Brand new word, about 20 years old. Oh, cool. Oh. I did not know that. Did not know that either. Brand new discipline. Word, perhaps people have used it. But it's a brand new discipline. A thing unto itself. There you go. Except you were interested in the sun long before that. So, what attracted you? Just because we like a little bit of bio on people every now and then. And someone with such intense interest in such an omnipresent object.

2:09You can ask, why isn't everybody interested in it? Or how come more people aren't? So, what got you into it?

Studying the sun as a laboratory

2:16You know, it's not a traditional approach, right? So, I'll give the most honest answer I can give, which is I came to the sun almost by accident. I was trained as an astrophysicist, interested in stars in general. And you know what that is all about, Neil. Then I realized that we spent studying stars that are light years away.

2:46And, you know, we have one star which sits only eight light minutes from us and allows us to examine it in exquisite detail. So, the sun became the most exciting laboratory I could imagine. We can see the surface change, listen to its interior, fly through its atmosphere of late, and watch its influence literally move all the way to Earth and the edge of the solar system, which is our Milky Way galaxy.

3:24Okay. So, right now, do you live in the sun? Is this your... And you just come out for interviews? We do live in the atmosphere of a living, breathing star. What can I say? Oh, good. I like that. I like that she did that. I like that she did there. Yes. That was good.

Helioseismology and measuring internal waves

3:44So, now, I remember coming through graduate school, there was a subfield of heliophysics called helioseismology. And they were, you know, borrowing the word from Earth, you know, seismology and Earth. Right. As you watch earthquake waves move through the Earth, and they refract and bend, and you can infer what the middle of the Earth is like. Okay. From the delayed signals from different points on Earth's surface. And so, that made sense to me, because Earth is like solid.

4:16The sun is not solid. So, when I heard them talk about this, it was like, yeah, okay, let's see what you got. But it's a real subfield. Could you tell me how that works? And is what's going on in the middle of the sun settled science at this point? Ooh. That's, well, you have to give me some time. A lot of questions kind of coupled together. Helioseismology is very much a well-established subgroup of heliophysics, solar physics.

4:50It's exactly how you describe. Now, sun is not solid. I think we all know that. But there are vibrations, sound vibrations, taking place in the interior of the sun. And that's what we, so we image the vibrations. And then infer, essentially, the interior properties of the sun, like the convection zone. You can't see inside the sun. Everything has to be inferred. That's inside the sun, everything.

5:21So is, are all scientists who study this inferring the same thing so that there's general agreement about what the middle of the sun is up to? Or is it like dentists, where you have four out of five dentists surveyed says that you should brush your teeth? I don't know who that fifth dentist is. He ain't got no teeth. Okay. Hey, let me say that we do our best. We are doing ultrasound on the sun, okay? It's not a dental office. That's what we are doing. So seismology is like, really, ultrasound.

5:54And the more observations you have, more continuous observations, that's why Solar Dynamics Observatory was created. You know, we needed 99.9% of the data continuously because any data gap can lead to erroneous results. So SDO, the Solar Dynamics Observatory, many of the images we've seen of the sun's surface in high detail are credited to that observatory. I assume that's in space somewhere, correct?

6:25It is in space somewhere. It's actually near our space. Because the volume of data is so high, we have our own dedicated ground station in New Mexico. So we couldn't send it to like L1. But we are watching the sun nearly 24-7. There are eclipse periods because of its orbit being close to Earth. But yes, there were a lot of thought. So if it was much, much closer to Earth, it would have daytime and nighttime.

6:56But you want near 24-7 observations. Obviously, the farther away from Earth, the less Earth is going to get in the way. Right. Right, right. Or anything else. Yeah, yeah, yeah. Well, it turns out in this episode, we were mining the questions that had accumulated in our cosmic queries search. And some of them are sun-related. And we exhumed them for just your arrival here. And then we'll get on with my conversation with you. So Chuck, you got questions for us?

7:27I got, we just got a few that are specifically for Lika. These are from our Patreon supporters. From our Patreon patrons. And by the way, whenever we get the opportunity to say thank you to the Patreon patrons, we definitely offer our heartfelt gratitude because, you know, you give us the money. The money. Don't be so crass. You say you give us support. I'm sorry. You freely give of yourself to support us. Thank you. See, that's how you do that. You give us your ideas. Yes. That's what they're doing. That's what they're doing. That's true.

7:57They do because they offer their questions. And perspectives. And perspectives. And, you know, so, okay, this is Lothar Irkins. I love the name Lothar. That's so cool. It's like a caveman name. Yeah, yeah, of course. Lothar. Lothar. Hello, Dr. T, Lord Nice, and Lika. Lothar from Edwardsville, Illinois.

Mass loss through fusion and solar wind

8:20Has anybody ever crunched the numbers on how much mass our son has lost since igniting the fusion process and recorded the results? Just curious. That's weird. Now, but the real question is, because the sun is radiating, is it indeed losing mass as it's radiating? That's the whole shebang. That's the shebang right there. Yeah, so the real question for Lika is, is this something you guys care about?

8:53Because you can calculate this. Right. Very simply, actually. Okay. We know how much energy is coming off the sun every second. Okay. Okay? Convert that into mass. Mass. Because it's making that energy by equals mc squared. Right. And now that's how much mass is losing per second. Now you ask, how many seconds has the sun been alive? Right. It was a little brighter in the past, but, and then you get a total mass. So, Lika, is this something that matters to the heliophysicist, the rate at which the sun is losing mass? Because I think the rate is pretty slow.

9:23Well, it's not so much the rate, but the fact that it is losing mass, how much mass, in what ways. In what ways, yes. So, the sun has two main leaks. You already mentioned one. Fusion of, it converts 600 million tons of hydrogen into helium. Of that, 4 million metric tons of mass is converted into energy. That's every second.

9:54You know, it's the E equal to mc squared that you mentioned. Yeah. Right. That's what's going on. That's amazing. But there is another one that people might not know about. And that is that solar wind carries away roughly another one to two million tons of matter each second. Okay. So, altogether, the sun at this present time is losing roughly between five and six million metric tons, basically.

10:27Right. Per second. And that sounds alarming until you actually remember the size of the sun, its mass. And over its lifetime, you know, people have calculated because all these scientists are basically nerds. So, you can imagine someone calculated this somewhere. Of course. And it's not a difficult calculation. So, over its lifetime, the total is only sort of an order of 0.03% of the total mass of the sun.

10:58So, the sun maintains its weight very well. Yeah. Unlike me.

11:05The sun knows the sun. You're accreting mass. I am accreting mass while the sun is maintaining its mass. Okay. So, if the sun has strong gravity, as we all know and love it, that's what keeps us in orbit. Yeah. How is it losing particles? Why don't the particles just stay with the sun? What accelerates them and sends them out? You are jumping to all kinds of settled signed questions, which I haven't even gone to. Oh. Okay. So, you are absolutely right.

11:35I mean, everything, you know, on the sun, things are governed by basically gravity, pressure, magnetic field. Close to the sun, that we call the corona, the particles are dominated by gravity and magnetic field. And then we get to a point where the temperature in the corona rises so much, pressure increases, and particles become what we call the solar wind.

12:08And that region is called the alphanic surface or alphancritical point, where the particles are no longer tethered to the sun by gravity. Hey, this is Kevin the Sommelier, and I support StarTalk on Patreon. You're listening to StarTalk with Neil deGrasse Tyson.

12:38All right.

What the sun would sound like in space

12:46This is Corey Haas, who says, Hey, simple question. Does the sun make noise if space allowed for sound to travel? Hmm. Well, you already mentioned that we do some ultrasound measurements. And so, if sound can move through it, I think this question is, anything we can listen in on? Is there some, or if there was some way for sound to cross the vacuum of space, what would the sun sound like?

13:19It's a deep, deep question, Neil. I find all sun questions to be deep, by the way. I love these questions. They seem ordinary on the face of it, but really, you have to think about it, right? So, the answer is, the sun is not quiet. I mean, imagine, as if I've said something. It rings like an enormous musical instrument, okay? With millions of overlapping pressure waves that I talked about that creates the field of helioseismology.

13:54And a strong family of these sort of oscillations around five minutes. And five-minute oscillation is kind of has been known for a while when we started actually measuring these surface waves. Now, Neil, you already said, right, we cannot hear that sound directly because the vacuum between the sun and earth does not carry ordinary acoustic waves. And I would say, thank God for that, space is nature's sort of finest soundproofing, cancelling device outside of the Bose acoustics, right?

14:34Yeah. I wish my bedroom was space. We still listen by, as I mentioned, by measuring the tiny motions, and we do it with ultrasound. So, if, and this is like, you know, I can't be certain about it, but if we could answer your question, Neil, somehow get those sounds to propagate in our environment, it is thought that that would sound like a loud, roaring lawnmower.

15:09Lawnmower? Yes.

15:13Only on weekends. Don't do that during the weekday. Well, at least it's not a leaf blower. It would be constant, okay? It's not going to stop. Oh, okay. That's the other thing, right? So, be grateful, Chuck, that space is a vacuum. Yes. Otherwise, we'd be living with that. Now, see, I would have thought it would have sounded like a frying egg. Oh, quick, quick, quick. Like that, that makes more sense. But a lawnmower, that's crazy. So, some of the big waves will do that.

15:43The little ones could be crackling like an egg, you know? Oh, okay. So, a couple of things. I just want to re-emphasize the concept of a pressure wave. Yeah, I was about to. So, when I speak, it creates a pulse of energy in the air that is a pulse that moves forward and backwards. Right. And so, it's that forward and backwards pulse that hits your eardrum to vibrate the eardrum. That causes it to vibrate the eardrum. Right. And that's how you move sound. So, now, normally, when you think of a pressure wave, not just from, well, speaking, when you hear pressure wave, often that is associated with an explosion, okay?

16:15Yeah. So, like, there's an explosion, and emanating from the explosion is the pressure wave, which is what does all the damage, right? Yes, exactly what does all the damage. It's an extreme pressure wave. An extreme pressure wave. Yeah. So, the sun— That's why if a sound is too loud, it'll blow out your eardrum. Right. The pressure wave is too high. Right on. Right. But here's what I want to know. Is the sun, with these pressure waves, is that the result of, like, explosions on the sun? Yeah. Yeah, so— Like, what is the cause of these pressure waves?

16:46You analogize it to a musical instrument. Who's playing—where's the orchestra? Well, in the—I mean, the deep-seated orchestra is always at the core, but I'm not going there. It's the convection zone, where there is, like, a pot of boiling plasma. Ooh. Okay, that creates the magnetic field and everything outward that we experience. So, these five-minute oscillations that you describe, that means something in the sun is repeating every five minutes. Ooh. Is it one of these sort of convective cells or something else?

17:19Yes, if you pattern, if you actually measure this, right? I said there are many resonant— Yes, overlapping. So, you see this. Wow. Okay. That is wild. Okay. And let me ask you this. One of the images I saw from the SDO, it was so close up, and you could see, like, the surface of the sun as though it was a gurgling, boiling—it was like a cauldron or something. Nice. And this—it's almost mesmerizing.

17:52You're just watching it boil.

17:59And, of course, if you were on the sun, you might hear it, but you would vaporize first. Oh, wow, yeah. That's the problem. You're going to fall down. There is no surface. Oh, yeah, yeah. You'll just descend. But you'll fall into that. It's got strong gravity. I mean, so many ways to think about this, right? Strange things will happen. All right. Interesting. That is interesting. Chuck, I think we have one more question before we resume the episode as intended. What do you have? All right.

The heliosphere and galactic boundaries

18:23Here we go.

The heliosphere and galactic boundaries

18:24This one is from Monopoly World. That's their handle? That's the handle that's given. Okay. All right. And Monopoly World says this. Please tell me everything about the heliosphere.

18:36Yeah. Do you have five hours? Really? I thought nobody would ever ask that question. All right. Sure. It's about time. Oh, seriously. I love this question, actually. And yeah, five hours would be an adequate amount of time. Neil, you want to introduce the subject? Then I'll follow. Let me stoke the engine. All right. And then she can drive the train where it needs to go. All right. So you'll crank it up. Allow me to remind people that the Greek word for the sun is helios.

19:09Helios. And it's where we get the name for the second element on the periodic table. Helium. Helium. discovered on the sun before it was discovered on earth. Oh, wow. So it was of the sun, helios. Nice. Yeah, yeah, yeah. And so heliosphere, you can ask, there's the sun, but how about everything outside the sun? Does the sun have any influence there? And if it does, let's still connect it back to the sun. So, Lika, correct me if I'm wrong. Everything that the sun touches, I feel like a lion king.

19:41Wherever the sun touches is your kingdom. Right. Okay. Wherever the sun influences particles and magnetic fields beyond itself is the heliosphere. Is the heliosphere. I think that's right. Is that correct? It is correct. Okay. It is correct. That's our entire solar system, isn't it? Well, let's find out. And the boundary, too. And the boundary as well. Yeah, it's very interesting. Remind me to give this analogy. But, you know, simply put, we all know that, I think we all know, that earth has a magnetic

20:18cocoon or a bubble. And think of it either way. We can't see it, touch it, but we feel it magnetically. And it's called the magnetosphere. Well, the sun creates a much larger cocoon or bubble with the solar wind. Solar wind doesn't stop anywhere. It continues to propagate, right? And it's a bubble that surrounds all the planets and presses against the local interstellar medium.

20:52This is like the boundary with our own Milky Way galaxy. That is the heliosphere. And I'd like to say that we have actually punched through the heliosphere. That is, I mean, NASA spacecraft launch in the 70s have done that, right? So, in the comedy worlds, they say, you were punching up.

21:17We are punching out. Out. Punching out. Yes. Yes. There you go. Yes. So, they are in the interstellar medium. And, you know, this boundary, just like we learned that the alphine surface boundary, we learned with Parker Solar Probe, that it's, we used to think of it's, you know, a spherical surface. That's what we scientists do. We start with the simplest assumptions till, you know, observations tell us something else.

21:48Well, it's the same thing here. This, because the two Voyager spacecraft went in two different directions, latitude, we know that the heliosphere is not a symmetric boundary, basically. So, it's a little closer on one side than on another side. Yeah. And they respond to the solar wind pressure, magnetic field. And this is, heliosphere is really our home. It protects us from the harmful cosmic radiation from the interstellar medium.

22:24So, technically, the heliosphere is the solar system. Don't be so planet biased about it. Yeah. Thank you. Well, you know, we don't. You know, it's a star's environment. I mean, other stars have environment bubbles. They are called astrospheres. So, this is sun's sphere. Okay. So, what about the magnetopause? Is that the sun going through like a change of life? Magnetopause? We pause. We pause.

22:55I'm going through magnetopause. Oh, it's hot. I am so hot. Oh, magnetopause is killing me. You pause there. You get your breath. Then you keep moving on. But these boundaries tend to have the word pause in them, if I remember my vocabulary. Yes, they do. And so, basically, what – so, magnetopause is kind of used in reference to Earth's magnetosphere.

23:26Heliopause is in reference to sun's magnetosphere, which is the heliosphere, et cetera. But what they're trying to do, they essentially describe physics laws, right? So, you know, is it gravity-dominated? Is it pressure-dominated? Is it magnetic fields sweeping out? Those are the conditions that these boundaries define. I remember the day.

23:57It was reported when the Voyager 1, I think, exited the heliosphere. Right. So, it's the heliopause at the end. And we were all excited, but we asked, well, how does it know? Right. And so, it has these sensors on board that knows where the sun is because of the sun's influence on them. But then you reach a point where the sensors went haywire. Right. And you couldn't find the sun. Couldn't find the – didn't know which way the sun was. Right. Because the sun's influence was dropping while the galactic influence was rising.

24:30There's a point where they were about the same, and you could no longer uniquely point which way the sun was. We'd say, it has left the solar system. It has left the solar system. Oh, yeah. That's pretty cool. It's like a compass needle behaves, right? Right. Yeah. You know, if you take it to the North Pole, what will it show? Yeah, which way is it going to point? Yeah. Well, I think it just points every way. It goes haywire. Every way it can. Yeah. If you were to personify that, oh, my gosh. Yeah. I don't know. I am without direction in my life.

25:01Right.

25:04Yeah. Yeah, for the first time. So when you look at the heliosphere, okay, and then you get to the pause, and now you have the galactic influence, right? Mm-hmm. Okay. Now, is the gravity of our star still influencing anything beyond that point as well? Yeah, that's a simple thing. The gravity goes forever. Goes forever. Forever. Chuck, you are so smart.

25:35My God. Nobody dare bring up such questions. Well, thank you. Awesome. So the sun's gravity extends forever, but so does Earth's gravity. Right. So does the moon's gravity. Right. So all that really matters to you is that somebody else's gravity that's dominating where you are. Gotcha. And we exploit that when we go to the moon. We only give the spacecraft enough energy to get to the point where the moon's gravity takes over.

26:08Gotcha. And then it falls towards the moon. Gotcha. I don't need rocket fuel to fall towards the moon. Yeah. So at that point, of course, Earth's gravity is still there, but it's dominated by the moon's gravity when you're close enough to the moon. Gotcha. Yeah, so that's where it's the gravity thing. So our sun's gravity, now here's the, is there something that could fall into the influence of our sun's gravity so far out that it pulls it into our solar system? Oh, yeah. Oh, yeah. Oh, yeah. Let me say, oh, yeah.

26:38Oh, yeah. Well, that isn't that subject for another topic. That's another topic. Another show. That's another show. Okay. A lot of controversy attached, but it's kind of fun. It's really fun. It is. Because we are beginning to look everywhere. And what we had taken for settled science is very unsettled. Ooh. Love that. And unsettling. And that, too. That, too. But may I add, you know, heliosphere is my favorite thing, right?

27:12May I add a couple of more? Please. Please. Do it, right? Because you were instructed to say everything there is to know about the heliosphere. That was your instructions. So, please proceed. So, heliosphere literally partly shields the planets from galactic cosmic radiation. And so, before you reach interstellar space, you first have to leave home. And that is our home. And two thoughts as I was thinking about this topic when I said bubble magnetosphere is a

27:44bubble or a cocoon. And same thing with sun's magnetosphere, which is the heliosphere. This is like a bubble within a bubble within a bubble. And it takes me to a fractal zone. It's like nature kind of knows how to replicate a good thing. I kind of want to embed that idea. This is how, you know, stars have astrosphere. So, everything you look around has this zone of magnetic field that we can't see, we can't touch, okay?

28:17And so, my final comment to you is that you live inside a star's gigantic magnetic embrace. It keeps you safe. Do not forget that. And thank it. Look at that. That's pretty cool. Now, it makes perfect sense that people used to worship the sun. Because they knew. They knew. They knew. They knew more than we did. They were like, hey, man, that thing is keeping us safe.

28:49All right? We need to show it a little respect.

Parker Solar Probe and the corona

28:51So, Lika, catch me up on the Parker Solar Probe. Because last I encountered it, I was telling everybody about how it achieved a speed record for any human-made object. Because there were some trajectories as it fell towards the sun where the sun accelerated it. And it was some still very small fraction of the speed of light, but faster than anything had been sent before. But the Parker Solar Probe, what was its mission and did it accomplish it?

29:24And is it still going? You know, I'm answering the last question first. Yes. Parker Solar Probe is going strong. You know, the first seven years it launched in 2018. The first seven years were basically dedicated to doing the prime mission. And after that, NASA is going to decide it as operating mission. So, what Parker Solar Probe has done now, after 24 orbits, it took it to its closest point, called the perihelion.

29:56It's about something like close to 10 solar radii, 3.8 million miles. But I know things in solar radii. It's inside of 10 solar radii. And that was important because we wanted to have a little bit of idea of crossing over from the alphan zone into the corona, where the particles actually become solar wind. So, we've done 24 of those and reached the closest point.

30:27And now, we just kind of finished, I think, 28th perihelion in June. Wait, wait, wait. Lika, is that closest point within the corona? Or is it still kind of safe outside the corona? Because you said 8 radii that feels a little distant. Fancy you would ask that, Neil. That's such a binary question. Seriously. Damn. Just getting dissed on my own shelf.

30:55So, I already told you, right, that the alphan surface, alphan zone, is not a spherically symmetric zone. It's not a 5 solar radii, 10 solar radii. We made lots of assumptions. There's not a sign there saying entering the alphan zone. No. So, we are actually close enough that we go in and out. And we are actually able to measure the pristine solar wind in the corona.

31:26That's very cool. That's the best of all world. That's how it was designed. If you're only in it, you're just getting the same measurement. Exactly. What good is that? That's really cool, actually. Very cool. Very cool. Very cool. Instead of going to the poles of the sun, that was the original idea of solar probe, said, hey, we are going to the sun. We are going to take, and that would have taken very little data, and said, no, we want data. And so, we created this alternate concept in the ecliptic, and we get Venus gravity de-assist momentum.

32:03So, it's between Venus and the closest point to sun. And that point is 3.8 million miles. But let's stick to solar radii. Solar radii. Okay. Yeah, the sun's diameter is almost a million miles across. Now, Lika said something just casually. Go ahead. But I got to stop on it and give an explanation. All right. Okay. She said, what's the word you used? De-accelerate. Oh, no, no, no.

32:33Gravitational de-assist. De-assist. The de-assist. Not de-ist. Okay, I'm sorry. But de-assist. The de-assist. As opposed to. We are so accustomed to hearing about gravitational assist. Assist. Because you have a probe that doesn't have enough energy to get to its destination. Right. You sneak up behind a planet. Right. You fall towards the planet. You gain its orbital speed, and you keep coming out the other side. Right. So, you can do this, boost your speed, get to wherever you want in the solar system. Okay. Here's the problem. You want to get to the sun. The sun is not in orbit.

33:03Right. We're in orbit. We're in orbit around it. And we launched it from here. Right. We've got to somehow eat that orbital speed. Right. We've got to get rid of it somehow so that we can fall in towards the sun. Because we don't want to overshoot it. Correct. Correct. So, if you come the other direction into a planet. Right. You get a de-assist. Ah. Okay. Gotcha. Yeah. And Venus is sitting there conveniently between us and the sun. And so, Venus is doing, doing, doing. Doing the breaking for us. Doing the breaking for us.

Solar cycles and magnetic activity

33:33That's really cool.

Solar cycles and magnetic activity

33:34So, it seems like, I don't know if it's true or not, that there's been more auroral activity visible at latitudes farther south than usual. Right. And the aurora, we know, comes from the solar wind. Right. And the solar wind is stoked, we know, from the solar cycle. Okay. So, Lika, tell me about the solar cycle. I know it's a big question, but how often do we have you? Okay. The solar cycle and what it does to the solar wind. And is the sun burping up more wind lately than historically?

34:08Or are we just better informed? Because we have space weather people saying, look north, go north, this weekend, aurora, check it out. There you go. Is it just our awareness or is it really happening? And what do sun burps smell like? Stop. Is it like pastrami? That has to be the next cosmic query question and I will answer.

34:33Not right now. Okay. Because I have to think about it. But it's a great question, I think. What will it answer? So, solar cycle, I mean, I don't even know. We talked about this in some of the previous shows. Yes, we did. Where to begin. But generally speaking, you know, solar, the convection zone that we talked about and the convection cells and all that. And the churning of plasma and creating magnetic field with dynamo, all of this creates kind of condition for generating.

35:08It is moving plasma creates magnetic field. That's the key thing to remember. It's the same process of dynamo anywhere. Right. But in the case of the sun, it has a beat. It has a couple of beats, actually. Well, I just want to add something there. So, it's not just moving plasma that creates magnetic field. It's any moving charge. Right. And a plasma is a charge cloud. Right. So, you get the magnetic field for free because there are free charges moving in the plasma. In the plasma. Right. But turbines and things that generate electricity, they have charges moving within a magnetic field.

35:43Right. And it creates a current. But anyway, so it's a broader fact than just a plasma moving through. Well, no, we have one on Earth, but it's because we have an iron core. Oh, in our core. Right. And it's liquid. But it's liquid. Yes. Otherwise, it would be dead. It's molten. The Earth cools completely. We lose our magnetic field. And when we're done, right? We're toast at that point. We just have to go underground. Oh. And now we're chuds. Now we're chuds. Okay. Please. Please continue, Lika. So, actually, kind of this is something, you know, talking about a little bit more. Whenever you hear the term electromagnetic, we really can't separate electricity and magnetism.

36:20They are coupled. They are coupled physical process. One generates the other. One's movement generates the other. And that's what you are saying, Neil. And it depends what's moving and what's stationary. And depending on that, you either create an electric field or a magnetic field. Yeah. There you go. Oh, that's cool. It's very cool. I mean, that's a great way to think about it. That's very cool. Yeah. That they're part of the same thing always. Yes. All right. Great. That's great. So, you have this turbulence.

36:51So, all this is happening. And so, we get, like, a couple of signatures from all of this. And that is roughly 11-year solar cycle, where the solar magnetic cycle peaks, where we get these sunspots, you know, big, gigantic freckles on the sun. They are dark, but they are dark not because they are less intense or energetically less, but because the magnetic field is so strong, it inhibits kind of, you know, outward propagation of radiation.

37:27So, you see it dimly in comparison to the rest of the surface. So, magnetic field. So, solar max is a period when you have lots of sunspots. They basically start at high, mid-latitude, 50 degrees north and south. So, then they gradually decline. And then we get into solar minimum. And in solar minimum, there are times when you have no sunspot. That doesn't mean the sun is dead. There is still sort of a basal magnetic field always.

37:58And these are things we are understanding better. But another interesting thing that happens is, and that's why I say two beats, right? So, there is the sort of the 11-year solar cycle, magnetic field increases, magnetic field decreases. But there is a flipping of the magnetic field also. So, magnetism has two poles, north and south pole. Take a bar magnet, and you will see those polarities if you put iron filings around them. So, in the case of the sun, what happens, you know, what was, say, one polarity in one hemisphere, say, northern hemisphere, changes completely in 11 years.

38:42But in 22 years, it goes back to its original polarity. And, Neil, you have to explain this. That's why it's called a one magnetic solar cycle as opposed to one solar cycle. So, the outboard effect of space weather kind of phenomenon doesn't care quite as much. We haven't at least seen its evidence. More data might lead us to understand it better. But they depend on, really, the intensity of the magnetic field and how many coronal mass ejections are happening, how many solar storms are happening.

39:20They happen in each cycle, from maximum to minimum. So, the space weather cares less about the polarity of the sun than it does about the intensity of the magnetic field at any given time. So, that's a fair statement, right? Well, I want to kind of be very clear about it because polarity does matter at Earth. But it is not the polarity on the sun. Okay. So, what the solar polarity is doing is less consequential to space weather. Yeah, that's all I was trying to say.

39:51But the coronal mass ejections, when they come towards Earth and interact with our magnetic field, our magnetosphere, then the polarity that the particles are carrying is very important. You know, in one case, you would actually have a reconnection and particles would penetrate, where our magnetosphere is no longer a bubble or a shield. In the other case, they are just going to get deflected. Just bounce off. So, they repel. So, comment, please, on the greater frequency of reported aurora.

Auroras and space weather impacts

40:48Because I looked at how peaky the last solar maximum was. It was not oddly high. Okay. It was, you know, maybe even a little low compared with an average over the last 50 years or so. Okay. Or 100 years. So, is this just better reporting? Because I, it was like 11 p.m., and I looked to my right. I was driving on Long Island. I looked to my right, and the sky was kind of glowing reddish. Okay. And I said, wait a minute, the sun set many hours ago.

41:19It can't be sunset colors. Wait a minute, I'm facing north. What the? So, I pulled over, pulled out my phone, my camera phone, and took a photo, which is, the phone is more sensitive than your eyes are to different colors. And there it was. Aurora? It was Aurora. Okay. And I had never seen Aurora on Long Island before in New York. And so, do you remember the time? Which month? I do remember the date. It was October 10th, 2024. And that year was Solar Max.

41:51Isn't that correct? Yep. Okay. Cool. So, are you friends with the Aurora? Like, yeah, I know that one. Well, I have sun's number. I could tell you a couple of stories about the sun. And so, this is, you're asking a very important question because it is a question in my mind. And someday, when I am not working professionally, I want to go back to science and actually kind of try to understand this.

42:21And I share whatever I experience and my speculative thoughts on this. I'm not going to go there right now. But it is a confluence of two things. We are all very aware. So, I would say heliophysics big year that I talked about in 2024 and overall, the outreach that NASA has done over the years has really seeped in to the community consciousness.

42:51So, people are paying more attention. We have better cameras. So, we are capturing this. But still, that doesn't answer everything. However, I do end every show saying, keep looking up. You should. You should. No, no, I do. Every show ends that way. So, maybe it's us. Right. Just seeing what we should be seeing because we actually did what we were supposed to do. We're looking up. We're looking up. So, that's a little piece of it. We don't know how big a piece. Keep going. A little piece of it. So, the aurora happens when solar wind particles come and interact, you know, with our atmosphere dislodging, you know, oxygen atoms to, you know, their electrons to higher orbits.

43:34And we get different colors, like green at 100, 200 kilometers, red with higher energy. These are all oxygen at higher elevation. And then you have blue and green for nitrogen. So, we kind of know all this, what exactly is going on. But remember one thing, that auroras are most visible in the higher southern or northern latitudes around the magnetic axis, which is substantially different from the actual geographic north-south axis.

44:10So, May 2024 was actually one of those auroras where basically it is the first G5. NOAA sort of describes storms in scales. And G5 is the highest geomagnetic storm scale. And so, that particular, the May 2024 aurora was G5 level, and it lit up all the way to Ladakh, India, to Florida.

44:44I mean, think about being south. It is incredibly south, right? So, if you allow me, I kind of want to describe, there are a couple of personal stories related to aurora that hadn't happened until this solar cycle. Oh, please. Yes. One is May 2024. You know, that happened between May 10th and 12th, 2024. I was in D.C. I didn't get to see the aurora.

45:15My friends took pictures, you know, as I would have seen it from our deck in Boulder and sent it to me. About a week earlier, a dear friend and colleague of mine, Dr. Jennifer Gannon, a space weather scientist from Boulder, passed away. And I was heartbroken. And I wrote a short piece on LinkedIn, essentially celebrating her life. And to me, it felt like that aurora display was nature celebrating her life.

45:48And I wrote a little haiku on that. Yeah. And this was actually picked up by White House. And we named our first solar storm as Gannon Storm. Oh, that's lovely. We meaning, you know, not anybody I know, but White House people, space weather people. This is incredible. You know, we have named hurricanes for 100 years.

46:22Right, right, right. But this is the first time that we named a storm. Well, that's beautiful. That's beautiful. Yeah, it really is. Well, thanks for sharing that. Yeah. There's one more. One more. Oh, another one. Okay. Well, because they are so personal, I cannot not say it. Please. So, in November 2025, now, you know, this is kind of a sad story. You know, in my life, who has looked at the sun, chased eclipses, studied everything, I had never seen an aurora with my own eyes.

47:00I had not. In November, between 11th to 13th of November, and this event reached the G4 scale of NOAA.

47:11It is like the sun did a private show for me. I saw an aurora so bright from 6.30 p.m. to 3 a.m. in the morning. And our neighbors thought, you know, I had gone crazy, you know, basically. Now, I myself have been in a position where I've seen colors from 6.30 p.m. to 3 a.m.

47:39I'm not sure. I'm not going to say it was aurora. I'm just going to say it was very beautiful. The sun didn't speak to you in color, but your mental state did, which is pretty awesome. Okay, that works sometimes, too. Pretty awesome. Why not? Why not? So, the sun has these storms every now and then. Okay. But they have to be aimed towards Earth for that to affect us in the way we describe for aurora.

48:11Right. Because if it's not aiming towards Earth, then it just misses Earth. Right. Then it goes to Mars or any other place or directly into heliosphere. Okay. I just want to be clear that not every storm observed on the sun results in aurora on Earth. So, with that in mind, I wanted to ask both of you. I can't remember the name of the movie, but I believe the opening scene is these catastrophic coronal mass ejections that are so massive that, now, in the movie they say these microwaves

48:44come to Earth and melt, like, half the damn, half a city. Okay, okay. And they're, like, very random. Some things melt, some things don't. That was in 2012? Is that 2012? Well, there's another one where they, geologists go to the middle of the Earth to find out what happened. That's the core. The core. That's the core. That's the core. Yeah. Yeah. I think you're talking about 2012. Is that 2012? Yeah. And they pulled that out of their ass. Really? Okay. You know what? What? I kind of, because we know so little, honestly, honestly.

49:17So it's not, okay, one thing we can say, we haven't seen this from the sun. We don't expect to see it, probabilistically speaking. But it is not impossible for other stars. We now study exoplanet, right? And I think heliophysics informs the exoplanet signs. So we have all these red dwarf stars with gigantic sunspots that we don't see on our sun. And they produce coronal mass ejections and storms that are of the gigantic proportion.

49:50And so what they could do, we don't know. I mean, that's why science is so beautiful. You know, we export our knowledge to any place in the universe. And sun and earth, they are our laboratories. Well, we even can bring past data into the present if it can give us insight into what we should fear. For example, spend a moment, because we're running a little bit short in time here, but there's stuff I want to make sure we hit.

50:21Was it 1859, this famous solar flare? Carrington event. The Carrington event. The famous solar flare that short-circuited the brand-new telegraphs that they had along the railroad to communicate from one station to another. Have we had that event since then, but we were not as susceptible? Or would such an event today knock out all of our satellites, which are right now, Elon alone has 12,000 satellites up there?

50:52It's actually a fascinating question, because one of the things we don't get to measure during such a term, even during Carrington event, I think there was only one magnetometer in Mumbai, Kolaba, Mumbai, that measured the actual magnetic field. So something happens on the sun, but something that all those mass magnetic field particles have to interact with Earth.

51:22That is where space weather phenomenon is actually happening, right? Where the ionosphere gets more ionized, where electricity sort of funnels through the soil into grids and we get power outages, where energetic particles can, you know, spoil satellite sensors, where astronauts are warned for radiation, where high-altitude aviation is susceptible, again, for radiation.

51:53What I want to know is, is it a G5, G10? What level storm will put our satellites at risk? Because we have a lot of assets right now in space. As a scientist in me, Neil, I think we limit ourselves when we put those restrictions. We don't know enough to say, because there are many different phenomena interacting with many different environments. There's magnetic field, there's energetic particles, there is radiation. So, sometimes even, and I can give you an example.

52:25Do you want me to give you an example? Please do. Please, please. Okay. So, I think in late January, early February 2022, Starling, you know, launched something like some 49 satellites, which it does very periodically. Everybody pays attention to space weather, what the sun is doing, and NOAA actually informs everyone. And so, they were aware there was a very mild coronal mass ejection going on.

52:57So, they were familiar and said, no, we can launch into that. They launched, and, you know, about 38 to 39 of those satellites didn't reach launch orbit with this really medium-class coronal mass ejection. So, what happened? What happened is that the sun launched many coronal mass ejections that gradually started heating the thermosphere, ionosphere, and created a lot of drag, and the Starling satellites didn't have enough propulsion, enough Delta V to launch them.

53:37Look at that. That's yet another way you can impact the health and safety of a satellite. Right. I forgot about that, Mika. Oh, my gosh.

Carrington events and satellite vulnerability

53:47So, do we know what level the Carrington event was from 1859? From every indication, it was absolutely G5, and I don't think we have the scales right. We get saturated, so we need to, you know, really think deeply. And I think NOAA and space weather community is thinking about it to really amplify the scales. Yeah, plus there are a lot of military satellites that are radiation-hardened. Yeah, they better be.

54:18So, there are ways you can sort of—and there are others. For example, you can—we have some of our telescopes. Depending on whether we're going into a meteor shower or some other phenomenon, we can actually put the telescope in safe mode. Okay. Where we close it down, turn it over. Right. And then—so, there are ways to mitigate this. That's why prediction is so important. Yeah. Space weather. The people just live in the space weather pages. Yeah. You know, people don't talk about space weather the way we talk about our weather.

54:50Hot enough for you? No, they don't do that. It's got real consequences. That is going to change, Chuck. Okay. Mark my world. Get me back in 10 years if I'm still here and not blended with the corona. And I'll prove myself right. If you blended with the corona, it would become that much more colorful. Oh, look at that, Neil. Thank you. Way to go. That was good. That was good, man. That was pretty good.

International missions to the sun

55:17All right.

International missions to the sun

55:18What's coming down the pike in the future in missions to the sun? So, the community, the world has launched, you know, lots of interesting missions. Punch, polarimeter to unify the corona and heliosphere. It's a constellation of four small satellites in polar, sun-synchronous, low-Earth orbit, and they image the solar wind. You know, that's a gap area in imaging, in understanding how solar storms are born on

55:55the surface of the sun and propagate through the corona into interplanetary medium and touch us here at Earth. And that is really going to connect in imaging from the surface of the sun all the way to Earth. And it's extraordinary science. You know, we can connect it to auroras in future. Then we have things like IMAP, right? Interstellar mapping and acceleration probe. And that is actually looking at the heliosphere, the original question.

56:28It operates from Lagrange point one with instruments. And it's kind of, it's still, it started taking its science data, I think, in February. And it is trying to sharpen sort of the discovery that one of the earlier missions called IBEX, Interstellar Boundary Explorer, found, which was discovery. You know, all of a sudden you look at the heliosphere from inside the heliosphere, inside the bubble, and you see this giant ring in high energy, energetic neutral atoms.

57:02So IMAP is going to shed light on that, but it also serves as a space weather buoy. I see what you did there. You said it would shed light on it. Yeah, I see that. You catch that? And so what you implied there is these missions, they can't use visible light because not all of this is giving us imageable substance in visible light. You need other bands of the spectrum to image the high energy, what bands of light, ultraviolet X-rays, I guess? Well, the ultraviolet X-rays, white light, infrared, all of those.

57:35But outside of that, yeah. I mean, some of these, you have to be outside of our atmosphere, otherwise they get absorbed. So that's why we have to launch. You know, before we launched sort of extreme ultraviolet and X-ray satellites, this is way back, right? We did not really know that the sun was a cauldron, as you described very early on, of this sort of seething plasma.

58:06You can't see that in white light. So Lika, is the United States a leader in the world in studying the sun or what other countries are players here in this space? Sun belongs to no one. And sun shines on every flag. There are very many interesting missions from all over the world. Europe plays a very big role, European Space Agency, Solar Orbiter, which is in partnership with NASA. And it takes us up to 30, 35 degrees above the ecliptic so we can view the poles of the

58:42sun, never before done before. We have Proba 3 also in Europe that created two spacecraft to create artificial eclipse, externally occulted coronagraph at extreme with two spacecraft. And they are finding out, again, sort of new sources of slow solar wind. The thing is, every time you look somewhere, you find something. So this is eclipses on demand. Eclipses. I love that. Eclipses on demand. Yeah.

59:13India launched Aditya L1. Aditya is sun in Sanskrit, which is sparked at L1, looking at the surface of the sun, interior with magnetic field of the sun, with in-situ instruments. So Aditya is Indian's eye on the sun. We have JAXA. JAXA, the Japanese Space Agency. Right. And then there is China.

59:44China is doing amazing stuff. So CUAFU L1 mission that was conceived of about 20 years ago, its launch, it's measuring all kinds of phenomenon, including X-rays. So what every agency is doing is looking at the gap areas that, you know, a while ago we had as a community created and trying to fill those gaps. Is this a cooperative effort?

1:00:15Is this information shared around the world with all the other scientists? So except for China, everything else is shared. Except for China. Right now. Right now. Yeah. And by the way, the Artemis Accords. Right. Which are a modern day attempt to create some level of cooperation in space. Right. In particular, if you discover something that could impact the safety or security of my next mission. Of somebody else. Either my hardware or my wetware, people.

1:00:46Right. The brains. Yes. Then you are obliged to share that. To share that. But China, last I checked, had not yet signed it. Hasn't signed it. But India has signed it. And the list of countries you'd expect have signed it. Right. And the list of countries you might expect wouldn't sign it, hasn't signed it yet. Of course. Russia. Yeah. Yeah. Of course. And a few others. Sunlight is spherically symmetric, shines everywhere. Everywhere. That's right. But how it touches us as human beings, our culture evolves. That's like that heliosphere, heliopause border, or the alphanic zone border.

1:01:22It's very crooked. There you go. Ooh. Look at that. That was profound. That's a mic drop. That's a mic drop. We like it. Well, Lika, that's all the time we have. This has been a delight to catch up with you. And thanks for sharing those two stories. Sad, but beautiful. And about your friend and about yourself. Yeah. And what role Aurora played within it. We'll have to catch up with you again. Just, you know, if the sun burps or anything or misbehaves, you're going to be on our hotline.

1:01:52Okay? Well, when you get those cosmic query questions, you know. Oh, yeah. Well, there it is. Absolutely. On the sun, heliosphere, because everything is under that. So. There you go. Everything under the sun. Under the sun.

1:02:08All right. Chuck, always good to have you, man. Always a pleasure. All right. This has been StarTalk. This was the heliophysics edition. Nice. I like that. Until next time, I bid you to keep looking up. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye.

1:02:39Bye. Bye. Bye.