Latest / Daniel and Kelly’s Extraordinary Universe / Can the Parker solar probe shed light on the Sun?

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Can the Parker solar probe shed light on the Sun? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Daniel, how did you get into physics in the first place.
0:11
Speaker 1: You know, it's kind of embarrassingly cliche. It was basically
0:14
Speaker 1: staring up at the night sky and just wondering about
0:17
Speaker 1: the stars and everything out there. That's not really cliche,
0:20
Speaker 1: you know. I think that's what gets most people interested
0:22
Speaker 1: in physics. But it doesn't make me wonder about something.
0:25
Speaker 1: You're wondering about my wondering. Well, if everyone's wondering about stars,
0:29
Speaker 1: why don't they focus more on the star that's closest
0:32
Speaker 1: to us, the Sun. I think it's a little bit
0:34
Speaker 1: more dangerous to stare at the Sun than it is
0:36
Speaker 1: to stare at the night sky. Why I didn't know
0:38
Speaker 1: physics was so dangerous. You're living on the edge, the
0:42
Speaker 1: edge of the Solar system. I'm taking lots of risks,
0:45
Speaker 1: napping in my office every day. It was like a
0:47
Speaker 1: sunny job. You got there. Hi am Orhand cartoonists and
1:05
Speaker 1: the creator of PhD comics. Hi. I'm Daniel. I'm a
1:08
Speaker 1: particle physicist and a professor at you see erline, and
1:12
Speaker 1: I'm a big fan of the sunshine. Oh yeah, you're
1:15
Speaker 1: a big sun bather. You like having a tan said
1:18
Speaker 1: with those reflective mirrors. I don't embody every Southern California stereotype,
1:24
Speaker 1: but I do enjoy a sunny day, you know, just
1:27
Speaker 1: like lifts my mood. I've lived in places where it's
1:30
Speaker 1: cloudy every day and it's just not as fun. Yeah,
1:33
Speaker 1: the sun is pretty warm out here in Southern California,
1:35
Speaker 1: and it's interesting because it means we're getting bathed by
1:39
Speaker 1: science every day almost as sent the time. It certainly
1:43
Speaker 1: affects our life. It grows all of our plans, that
1:45
Speaker 1: controls the weather. It basically is in charge of everything
1:49
Speaker 1: that happens on the surface of the Earth. And so
1:52
Speaker 1: you think we might understand it a little bit better
1:54
Speaker 1: than we do. Are you saying we need to shed
1:56
Speaker 1: some sunlight on the sun? We need to uminate those mysteries.
2:01
Speaker 1: Welcome to our podcast Daniel and Jorge Explain the Universe,
2:04
Speaker 1: a production of I Heart Radio in which we try
2:07
Speaker 1: to shine a light on everything we do and don't
2:09
Speaker 1: know about the universe. Our curiosity knows no bounds as
2:14
Speaker 1: it flies from the surface of the Earth down to
2:16
Speaker 1: the tiny particles all the way out to the workings
2:19
Speaker 1: of the Sun. At the heart of our solar system,
2:22
Speaker 1: the fiery fusion engine that powers everything, including life on
2:26
Speaker 1: Earth and the sparkling stars in our sky. We dig
2:30
Speaker 1: into all of those mysteries and try to explain all
2:32
Speaker 1: of them to you as best we can. Yeah, because
2:35
Speaker 1: it is a bright and sunny universe, shining bright with
2:37
Speaker 1: amazing knowledge. We're ready for us to bathe in it
2:40
Speaker 1: and take it in and become an intent our brains,
2:43
Speaker 1: I guess, to make them more colorful and knowledgeable about
2:46
Speaker 1: how things work and why things are the way they are.
2:49
Speaker 1: I really like that picture of the universe as sending
2:53
Speaker 1: us information, is beaming us clues about how the universe works. Because,
2:57
Speaker 1: as we've often limited, we are trapped here on this
3:00
Speaker 1: little rock, mostly unable to physically explore the universe, but
3:03
Speaker 1: we can decode those signals. The universe is zapping us
3:07
Speaker 1: information about what's going on elsewhere, letting us put the
3:10
Speaker 1: pieces together to try to build a mental model of
3:13
Speaker 1: what is happening far far away. Yeah, and it's pretty amazing.
3:16
Speaker 1: We are in a little tiny corner of a galaxy,
3:19
Speaker 1: in a tiny corner of a supercluster of galaxies, in
3:22
Speaker 1: a tiny corner of the universe, and yet just from
3:24
Speaker 1: the light we get from other suns out there in
3:26
Speaker 1: the universe were able to kind of piece together a
3:29
Speaker 1: huge picture of the entire universe. It really is incredible
3:33
Speaker 1: how much we do know about things happening far far away.
3:36
Speaker 1: We have models of little stars and big stars, and
3:39
Speaker 1: star lifetimes and star deaths and star explosions and star implosions,
3:44
Speaker 1: all just from watching from this little rocky perch in
3:47
Speaker 1: the suburbs of the Milky Way. And that knowledge has
3:50
Speaker 1: been developed over many, many years, people staying up late
3:53
Speaker 1: at night, freezing their bones to look up in the
3:56
Speaker 1: night sky and take careful notes, and developing fancy new
3:58
Speaker 1: technology to take better pictures of what's going on out there,
4:02
Speaker 1: and more recently actually sending probes out to explore our
4:05
Speaker 1: neighborhood and try to learn a little bit closer up
4:08
Speaker 1: what's going on. Yeah, because we can learn a lot
4:10
Speaker 1: about stars and also about the star that's closest to us,
4:15
Speaker 1: the Sun. It's kind of easy to forget that the
4:17
Speaker 1: Sun is a star. You know, like, if you're an
4:19
Speaker 1: alien in another planet and you look up at the
4:21
Speaker 1: sky and you see a tiny pinpoint shining bright in
4:24
Speaker 1: the darkness, that could be us, That could be our sun.
4:26
Speaker 1: Sending them information about the universe in US. Yeah, and
4:30
Speaker 1: I think the phrase solar system is sort of underappreciated.
4:35
Speaker 1: It's not just that we have a star and it's
4:37
Speaker 1: at the center of the system. We really are part
4:41
Speaker 1: of our star. In some sense, we are living in
4:43
Speaker 1: the atmosphere of our star. It really does dominate the
4:47
Speaker 1: Solar system in a way I think people don't really understand.
4:50
Speaker 1: It's of the mass of the Solar System is in
4:54
Speaker 1: that star, and it's sending out enormous waves of energy
4:58
Speaker 1: and particles all throughout the Solar system. So you could
5:02
Speaker 1: say we're just sort of like flying high in the
5:04
Speaker 1: very outskirts of the solar atmosphere. You know, we are
5:07
Speaker 1: a tiny little part of the Solar system. It is
5:10
Speaker 1: basically the Sun, the whole Solar system. We're almost like
5:12
Speaker 1: little tiny moons on a giant exploding ball of fire. Yeah,
5:18
Speaker 1: you could say that we live on the Sun. You know,
5:20
Speaker 1: in some sense. The edge of the Sun is not
5:23
Speaker 1: really something that's well defined. You could say the whole
5:25
Speaker 1: Solar system is basically just the Sun, and we are
5:28
Speaker 1: part of it. Yeah. And even though it is the
5:30
Speaker 1: closest start to our system, and it provides light for
5:33
Speaker 1: us and heat and which powers all of life on
5:37
Speaker 1: this planet. There's a lot that we surprisingly don't know
5:40
Speaker 1: about our own son. It is fundamentally important to everything
5:44
Speaker 1: we do. It's the best example of a process that
5:47
Speaker 1: happens all over the universe, and it's really important for
5:50
Speaker 1: the universe looking the way that it does. And yet
5:53
Speaker 1: we still have basic questions about what's going on inside
5:56
Speaker 1: our star, how it all works, and how it's even
6:00
Speaker 1: stable for it to get so hot. Yeah, and it
6:02
Speaker 1: seems like an important question right to understand this giant
6:05
Speaker 1: exploding ball of nuclear powered fusion happening right next to us,
6:10
Speaker 1: you know, like, is gonna keep doing that? Is it
6:12
Speaker 1: going to go out? Is it gonna explode? What's going
6:14
Speaker 1: to happen to it? It It seems like important to find
6:16
Speaker 1: out what's going on there. Yeah, if I lived right
6:18
Speaker 1: next to a fusion reactor, I want to understand pretty
6:21
Speaker 1: well if it was going to blow up or if
6:23
Speaker 1: it was going to fail, or what it was going
6:25
Speaker 1: to do, and why it's it's suddenly so hot. There
6:27
Speaker 1: are lots of practical reasons to understand the Sun. It's
6:30
Speaker 1: also just a great mystery, like it's doing so much cool,
6:33
Speaker 1: amazing important stuff, huge tubes of plasma, superheated, incredibly powerful
6:38
Speaker 1: magnetic fields. It's just a great laboratory for understanding, like
6:42
Speaker 1: what can the universe do? After all? How do all
6:46
Speaker 1: these forces come together in extreme environments to create such
6:50
Speaker 1: a dramatic and beautiful display. Yeah, I'm not sure I
6:53
Speaker 1: would call what the Sun is doing cool. It's more
6:55
Speaker 1: like maybe little. It's sisslingly hot. Yeah, there's a lot
6:58
Speaker 1: we don't know about the Sun, and so today on
7:00
Speaker 1: the podcast, we'll be asking the question what will the
7:08
Speaker 1: Parker Solar Probe teachers? I'm guessing things about the Sun? Yeah,
7:15
Speaker 1: the Parker Solar Probe is a really fun piece of
7:18
Speaker 1: technology that humanity designed, build and launched out to go
7:22
Speaker 1: and explore, to visit up close the Sun and to
7:26
Speaker 1: try to get some answers to some pretty basic questions
7:29
Speaker 1: about how the Sun works. Yeah, it's a pretty cool
7:33
Speaker 1: NASA project, one which I made a comic about last year.
7:36
Speaker 1: I don't know if you know those for Physics magazine.
7:38
Speaker 1: Oh no, awesome, I didn't see that. Yeah. I had
7:40
Speaker 1: to interview a bunch of scientists for it, and I
7:42
Speaker 1: put out a comic of your Google, peachd Comics and
7:45
Speaker 1: Parker Solar Probe. You will find it in case you
7:47
Speaker 1: need like a visual companion to this episode. Awesome. I
7:51
Speaker 1: encouraged everyone to check that out. Jorges cartoons explaining signs
7:55
Speaker 1: are always super well done and the visual is always
7:58
Speaker 1: very helpful. Yeah, it is a pretty your sting and
8:00
Speaker 1: fascinating project over at NASA there and so, as usually,
8:03
Speaker 1: we were wondering how many people had heard about the
8:05
Speaker 1: Parker Solar Probe and what they know about it. So
8:08
Speaker 1: thank you very much to everybody who volunteers for this
8:10
Speaker 1: segment of the podcast. We'd love to hear your voice
8:13
Speaker 1: as well. If you've been listening for a while but
8:16
Speaker 1: never screwed up the courage to write in, please don't
8:18
Speaker 1: be shy reach out to me at questions at Daniel
8:21
Speaker 1: and Jorge dot com. So think about it for a second.
8:23
Speaker 1: Have you heard the Parker Solar Probe. Here's what people
8:26
Speaker 1: have to say. I actually learned some things about the
8:29
Speaker 1: Parker Solar Probe recently, and that that well, study the
8:33
Speaker 1: older atmosphere of the Sun or the outer corona, and
8:37
Speaker 1: to learn why it is hotter actually then the surface
8:42
Speaker 1: of the Sun. I believe the Parker Solar Probe is
8:46
Speaker 1: designed to investigate some of the physics behind the fusion
8:52
Speaker 1: of our Sun and perhaps try to explain why there
8:56
Speaker 1: is a temperature differential whereby the gases that are expelled
9:01
Speaker 1: or the atmosphere of the Sun that is farther away
9:04
Speaker 1: from the surface actually heats up as it leaves the
9:08
Speaker 1: surface of the Sun. So I guess it's going to
9:11
Speaker 1: the Sun, the Parker Solar Probe. So I feel like
9:15
Speaker 1: I could probably tell us about pangnetic field or maybe
9:19
Speaker 1: solar flares or um and stuff like that. I have
9:23
Speaker 1: absolutely no idea speculating. I would imagine that it would
9:26
Speaker 1: be something that would go out into the Solar system
9:28
Speaker 1: in order to collect information on things that we otherwise
9:31
Speaker 1: can't infer, such as particles in space, radiation from this
9:36
Speaker 1: point in space, or perhaps a different perspective that we
9:39
Speaker 1: can't get from Earth. I have no idea what the
9:42
Speaker 1: Parker Solar Probe is. I don't know I would get
9:44
Speaker 1: something to do with like temperature radiation, have no clue,
9:48
Speaker 1: maybe solar flares. Not a lot of name recognition, but
9:51
Speaker 1: I think people are sort of pieced together that it's
9:53
Speaker 1: probing the Sun Yeah, but people seem excited to learn
9:56
Speaker 1: about what the Parker Solar Probe might teach us about
9:59
Speaker 1: the mystery of the source of all energy and life
10:02
Speaker 1: on Earth. Yeah, and so let's dig into it, or
10:05
Speaker 1: I guess, let's go out into the Sun with this idea.
10:08
Speaker 1: First of all, what is the Parker Solar Probe? So,
10:11
Speaker 1: the Parker Solar Probe is a really cool project. It's
10:14
Speaker 1: a spacecraft launched from Earth to go investigate the Sun. Basically,
10:19
Speaker 1: to do a bunch of really close fly bys close
10:22
Speaker 1: sort of by solar standards, and measure a bunch of
10:25
Speaker 1: things about the Sun, to try to get a handle
10:28
Speaker 1: on some long standing mysteries about how the Sun works,
10:32
Speaker 1: what's going on inside it, how it gets so hot,
10:35
Speaker 1: and the solar wind that flies out from it. And
10:37
Speaker 1: so in the end, it's just a satellite that we
10:39
Speaker 1: launched from here. It zooms around Venus a few times
10:42
Speaker 1: and makes a bunch of approaches to the Sun and
10:44
Speaker 1: gathers a bunch of data about what's going on. Well,
10:47
Speaker 1: you can't just call it a satellite. It's more like
10:49
Speaker 1: a spaceship, right, spacecraft, that's right. It's not a satellite
10:52
Speaker 1: in the sense that it's orbiting the Earth, it will
10:54
Speaker 1: be orbiting the Sun, so in that sense, it's a
10:56
Speaker 1: satellite of the Sun. But yeah, spacecraft is definitely cool, ruler,
11:00
Speaker 1: and this one contains a lot of really cool technological
11:03
Speaker 1: advances to let it like survive getting so close to
11:06
Speaker 1: the Sun. It's going to get closer to the Sun
11:08
Speaker 1: than any human object ever has and it's going to
11:11
Speaker 1: have a velocity with respect to the Sun greater than
11:14
Speaker 1: any human object has achieved. Super cool. But this is
11:17
Speaker 1: not the first spacecraft we sent to the Sun, right
11:20
Speaker 1: for the first spacecraft we've used to study the Sun.
11:23
Speaker 1: This is kind of the latest and most awesome and
11:26
Speaker 1: the one that's going to get to the Sun the closest. Yeah,
11:28
Speaker 1: the last spacecraft to go visit the Sun before this
11:31
Speaker 1: was the Helios two in nineteen seventy six. So it's
11:35
Speaker 1: been a few decades since we've visited the Sun. It's
11:37
Speaker 1: been a lot of planning, a lot of technological advancements,
11:40
Speaker 1: a lot of ideas, a lot of arguing at NASA
11:43
Speaker 1: budget meetings. So it's exciting to get to go back
11:45
Speaker 1: to the Sun with new technologies and upgraded instruments and
11:48
Speaker 1: to get closer as you said than ever before. Yeah,
11:52
Speaker 1: it's a hot mission, and it's a long mission to write.
11:55
Speaker 1: It's didn't just take decades to get it going, but
11:59
Speaker 1: the mission itself office is several years. It was launched
12:02
Speaker 1: in August of two eighteen, and you know, even when
12:04
Speaker 1: it launched, it was already unique for a couple of reasons.
12:07
Speaker 1: One is that it was named after a living person.
12:10
Speaker 1: Eugene Parker, who's a famous theorist about how the Sun works,
12:14
Speaker 1: was alive at the time it was launched, even though
12:16
Speaker 1: he was ninety one, and he was on hand to
12:18
Speaker 1: observe the launch, which is really cool. Also, it contained
12:21
Speaker 1: the names of more than a million people who wanted
12:24
Speaker 1: their name to sort of touch the Sun. NASA let
12:27
Speaker 1: people submit their names and they wrote down more than
12:30
Speaker 1: one point one million submissions, put it on a memory
12:33
Speaker 1: card and slapped it on the outside of the probe,
12:35
Speaker 1: so those people could sort of ride along and go
12:38
Speaker 1: visit the Sun with them. No kidding, for real, They
12:41
Speaker 1: just like duct tape a little flash drive to the outside. Yeah,
12:44
Speaker 1: there was a memory card mounted on the plaque so
12:46
Speaker 1: that all those people could feel like they went to
12:48
Speaker 1: visit the Sun. Pretty cool, but you're right, there's gonna
12:51
Speaker 1: be like twenty four solar orbits in a seven year mission.
12:55
Speaker 1: So it's going to zip around the Sun a bunch
12:57
Speaker 1: of times, and it goes sort of between the Sun
13:00
Speaker 1: and Venus and the Sun and Venus, and some of
13:02
Speaker 1: those visits are closer to the Sun and some of
13:04
Speaker 1: them are further from the Sun. Also, remember that the
13:06
Speaker 1: Sun has a weird cycle of its own. It's about
13:08
Speaker 1: eleven years, so the mission lasts long enough to allow
13:10
Speaker 1: us to sample the Sun several times in different places
13:14
Speaker 1: in its own internal cycle. M what do you mean
13:17
Speaker 1: the Sun has a cycle like it It's it's not moving.
13:20
Speaker 1: I mean it's moving through space, but it's not really
13:22
Speaker 1: were respective the solar system. It's more like has cycles
13:25
Speaker 1: of its temperature and size. Right. Yeah, people have been
13:28
Speaker 1: noticing over the last few hundred years that there's an
13:31
Speaker 1: eleven year cycle of the Sun. Over eleven years, you
13:35
Speaker 1: see like the number of sun spots rise and then fall.
13:38
Speaker 1: And people have been recording this four hundreds of years.
13:40
Speaker 1: It's something we've known about it for quite a while.
13:42
Speaker 1: And so the number of like solar flares and corona
13:45
Speaker 1: loops increase and then fall, and actually they think that
13:49
Speaker 1: this cycle has been pretty stable for like hundreds of
13:52
Speaker 1: millions of years. They see evidence of this going back
13:56
Speaker 1: to like the impact on ancient tree rings that have
13:59
Speaker 1: they dung up, like fossilized tree rings from hundreds of
14:02
Speaker 1: millions of years ago show these same kind of cycles.
14:06
Speaker 1: Are you saying the trees are the original scientists, solar
14:09
Speaker 1: scientists of Earth. It's incredible how sensitive life on Earth
14:14
Speaker 1: is to like the mood of the Sun. As the
14:17
Speaker 1: Sun gets hotter, it changes the weather on Earth in
14:19
Speaker 1: a way that we can measure hundreds of millions of
14:22
Speaker 1: years later because of the impact on the trees. And
14:24
Speaker 1: it's not just the Sun's weather. The Sun's magnetic field
14:27
Speaker 1: also flips every eleven years. Remember, the Earth's magnetic field
14:32
Speaker 1: also flips, but it's very irregular. Sometimes it flips every
14:35
Speaker 1: fifty thousand years, sometimes every million years. The Sun's magnetic
14:39
Speaker 1: field flips every eleven years. So that's all part of
14:42
Speaker 1: the solar cycle that people want to understand. And so
14:44
Speaker 1: the mission is like seven years long to try to
14:46
Speaker 1: gather data from different parts of that solar cycle. Yeah,
14:49
Speaker 1: super interesting. Now for the probe. One thing that I
14:52
Speaker 1: found interesting when I talked to scientists about this was
14:55
Speaker 1: that it's actually really hard to get close to the Sun.
14:58
Speaker 1: Like you would have thought that sending something to design,
15:01
Speaker 1: you just kind of put it in space and then
15:02
Speaker 1: the gravity makes it fall towards the Sun. But actually
15:04
Speaker 1: you need a lot of energy to slow down your
15:06
Speaker 1: space graph in order to get close to the Sun. Yeah,
15:09
Speaker 1: as you fall towards the inner Solar System, you speed
15:11
Speaker 1: up because you're trading gravitational potential energy for kinetic energy,
15:15
Speaker 1: and so you likely to sort of like whizz around
15:17
Speaker 1: the back of the Sun. That's true because you have
15:20
Speaker 1: angular momentum and it doesn't go away, right, and so
15:23
Speaker 1: you need to use some energy to basically lose angular
15:26
Speaker 1: momentum if you want to actually fall into the Sun.
15:29
Speaker 1: And that's why it goes around Venus, right. It kind
15:31
Speaker 1: of uses Venus's gravity to slow itself down exactly, uses
15:35
Speaker 1: Venus as like a gravity assist and it's gonna do
15:39
Speaker 1: like five different flybys of Venus to try to shed
15:42
Speaker 1: some of that energy so we can get closer to
15:43
Speaker 1: the Sun. There were previous designs for this mission back
15:47
Speaker 1: in earlier iterations, when it was going to use Jupiter
15:50
Speaker 1: as a gravity assiste. And also have like a bunch
15:52
Speaker 1: of nuclear power on board to try to help it
15:54
Speaker 1: get even closer. So previous designs, we're going to get
15:57
Speaker 1: even closer to the Sun than the actual spacecraft that
16:00
Speaker 1: they launched, but it wasn't going to be near the
16:02
Speaker 1: Sun as long. It was gonna be like a very
16:04
Speaker 1: fast close fly by. So they opted for this approach,
16:07
Speaker 1: which is cheaper, didn't require nuclear power, and give them
16:10
Speaker 1: a longer visit to the Sun, even though it's a
16:12
Speaker 1: little bit further than the original design. Yeah, and so
16:14
Speaker 1: it's on this kind of elliptical orbit where it's kind
16:17
Speaker 1: of swinging between Venus and the Sun. You can imagine
16:21
Speaker 1: like in the ellips Like one end of the ellipse
16:23
Speaker 1: is really close to the Sun, and that's the fly
16:25
Speaker 1: by they do close to the Sun to take data
16:28
Speaker 1: from the Sun exactly. So it's going around. Remember this
16:30
Speaker 1: is like a multi year mission. It's gonna be like
16:32
Speaker 1: twenty four solar orbits. As of October two, it's done
16:37
Speaker 1: thirteen of those so far, and so it's like more
16:41
Speaker 1: than halfway through its life, but there's a lot more
16:43
Speaker 1: coming and we're all looking forward to it getting closer
16:47
Speaker 1: to the Sun. It hasn't yet reached its closest approach,
16:50
Speaker 1: and also it's sampling the solar maximum, which is going
16:53
Speaker 1: to happen in around five that's when the Sun is
16:56
Speaker 1: like at its peak of solar activity. Mm. Yeah, because
17:00
Speaker 1: every time it goes near the Sun, it gets a
17:02
Speaker 1: little bit closer each time, right, Like the orbits are
17:05
Speaker 1: getting smaller and smaller. Yeah, if you look at a
17:07
Speaker 1: map of the orbits, you see it's sort of cork
17:09
Speaker 1: screwing around in this elliptical path, as you say, between
17:12
Speaker 1: the Sun and Venus, so sort of like zooming in
17:15
Speaker 1: on the Sun. Yeah, it's pretty cool that we can
17:17
Speaker 1: like navigate a spacecraft around the Solar System like that,
17:20
Speaker 1: like swinging between the Sun and then on the planet. Yeah.
17:23
Speaker 1: It requires really precise knowledge of where everything is in
17:25
Speaker 1: the Solar System and also a really detailed understanding of gravity.
17:29
Speaker 1: You know, these are also really exquisite tests of our
17:32
Speaker 1: understanding of how gravity works, because you're talking about throwing
17:35
Speaker 1: a rock and basically predicting where it's going to be
17:38
Speaker 1: in ten years right as everything is flying around the
17:42
Speaker 1: Solar System. So it's incredible precision and really awesome sort
17:45
Speaker 1: of control over the physics of the Solar system and gravity. Yeah,
17:50
Speaker 1: you don't want to fall short on that knowledge of
17:52
Speaker 1: gravity when you're sending something close to the Sun. Yeah,
17:55
Speaker 1: and so this thing is going to get closer than
17:57
Speaker 1: anything has ever gotten to the Sun before by actor
18:00
Speaker 1: of seven though when you say the number doesn't actually
18:03
Speaker 1: sound that impressive. It's going to get within four million
18:06
Speaker 1: miles of the Sun. It's like just under five of
18:10
Speaker 1: one au the distance from the Sun to the Earth.
18:13
Speaker 1: But that is seven times closer than any previous mission,
18:17
Speaker 1: and it's going to be within ten times the radius
18:20
Speaker 1: of the Sun. Yeah, it sounds like a lot, but
18:23
Speaker 1: it's actually super different close to the Sun and super
18:26
Speaker 1: dangerous and in fact, people I think one of the
18:29
Speaker 1: ways they described is that it's actually gonna touch the
18:31
Speaker 1: Sun in a way, and we'll talk about that later
18:34
Speaker 1: about what that means. Yeah, it's cool to think about
18:36
Speaker 1: touching the Sun. That we can of course argue about
18:38
Speaker 1: what it means to touch it, because like where is
18:40
Speaker 1: the edge of the Sun In some definitions, we're already
18:43
Speaker 1: in the Sun. And it's definitely fascinating to get nearer
18:46
Speaker 1: to the Sun and to study up close what's going
18:49
Speaker 1: on with its magnetic fields and its corona and the
18:51
Speaker 1: solar wind and maybe even understanding what's going on inside
18:55
Speaker 1: it to generate all these cycles. Yeah, and as the
18:58
Speaker 1: sent this probe to the Sun to learn about its mysteries,
19:01
Speaker 1: there are still a lot of things we don't know
19:03
Speaker 1: about the Sun, and so we'll get into those. But
19:05
Speaker 1: first let's take a quick break. All Right, it's the
19:21
Speaker 1: sunny day here in southern California, and we're talking about
19:23
Speaker 1: the Sun and the probe that NASA has sent to
19:26
Speaker 1: study it, the Parker Solar Probe, launched in August, and
19:31
Speaker 1: it's been making closer and closer passes to the Sun,
19:34
Speaker 1: getting us closer to what's going on there in the
19:37
Speaker 1: inside of the Sun and in its atmosphere, to learn
19:39
Speaker 1: about some of the deep mysteries we still have about
19:42
Speaker 1: how it works and what's going on inside there and
19:44
Speaker 1: outside of it. Yeah, you think that after studying the
19:47
Speaker 1: Sun for hundreds or thousands of years, that we might
19:50
Speaker 1: understand better this fusion engine at the heart of our
19:53
Speaker 1: solar system, the thing that's basically making all life on
19:57
Speaker 1: Earth possible. And while we do have some understand of
20:00
Speaker 1: how stars work in general, there are a lot of
20:03
Speaker 1: big mysteries remaining about basic facts about the sun. Yeah,
20:07
Speaker 1: like why don't my kids like to put on sun block?
20:09
Speaker 1: It's a huge mystery to me. The fight to the death.
20:11
Speaker 1: Maybe you should move somewhere less sunny, Maybe you should
20:14
Speaker 1: get them into the habit of wearing hats. Perhaps, But
20:16
Speaker 1: the Sun does have a lot of interesting and pretty
20:19
Speaker 1: deep mysteries about it that we still don't know, and
20:21
Speaker 1: so let's dig into those, Daniel, what are some of
20:23
Speaker 1: the unknowns about the Sun or the sun knowns? One
20:27
Speaker 1: of my favorite mysteries about the Sun is just why
20:30
Speaker 1: the outside of it is so hot. You know, the
20:32
Speaker 1: Sun is of course very very hot. It's thousands of
20:35
Speaker 1: degrees at its surface, and that's where the light that
20:38
Speaker 1: you see is generated. Remember we talked on the podcast
20:41
Speaker 1: several times about the connection between temperature and wavelength. Everything
20:45
Speaker 1: in the universe radiates light, and the light that it
20:48
Speaker 1: radiates depends on its temperature. And the Sun is several
20:52
Speaker 1: thousand degrees kelvin and at that temperature you tend to
20:55
Speaker 1: radiate in the visible spectrum. And it's no coincidence, of course,
20:58
Speaker 1: that the Sun tends to give off light in the
21:00
Speaker 1: visible spectrum. Our eyes evolved in this environment in order
21:03
Speaker 1: to see the light typically given off by the Sun.
21:06
Speaker 1: And so the sun itself is several thousand degrees kelvin.
21:10
Speaker 1: But around the sun is something called the corona, which
21:13
Speaker 1: is much much hotter than the Sun itself. And that's
21:16
Speaker 1: a really big mystery how that gets so hot and
21:19
Speaker 1: how it stays so hot. Yeah, it's a really weird thing,
21:22
Speaker 1: and it's a little bit hard to wrap your head
21:24
Speaker 1: around because the Sun itself is not one temperature, right, Like,
21:27
Speaker 1: the core of the Sun is super duper, duper duper
21:30
Speaker 1: hot because that's where all the fusion is going on.
21:32
Speaker 1: But as you get closer to the surface, it's sort
21:34
Speaker 1: of cools off, right, Like the surface of the sun
21:37
Speaker 1: is much cooler than the center of the Sun. But
21:41
Speaker 1: then if you keep going out further past the surface,
21:43
Speaker 1: it actually starts to get hotter. Again. It's like having
21:46
Speaker 1: a light bulb where the air around the lightbulb is
21:49
Speaker 1: hotter than the surface of the light bulb itself. Expect
21:52
Speaker 1: the hottest point to be the center. This is the
21:54
Speaker 1: source of the heat where most of the fusion is
21:56
Speaker 1: happening until the star gets much much older, of course,
21:59
Speaker 1: but in a star the to the age of our Sun.
22:01
Speaker 1: Mostly you have hydrogen fusion at the core which is
22:04
Speaker 1: driving it, and then it cools off, as you say,
22:06
Speaker 1: as you get to the outer regions. But then it
22:08
Speaker 1: weirdly spikes again. So this part the corona is hotter
22:11
Speaker 1: than the actual surface of the Sun itself. It can
22:14
Speaker 1: be like hundreds of times hotter. The corona is like
22:18
Speaker 1: millions of degrees kelvin. Yeah, it's super weird. It's like
22:21
Speaker 1: you said, it's like you can imagine the air around
22:24
Speaker 1: a light bulb hotter than the actual surface of the
22:27
Speaker 1: light bulb. Like, what's going on there? How is that possible?
22:30
Speaker 1: It's a big mystery, and it's been a mystery for
22:33
Speaker 1: more than a hundred years. People who have been studying
22:36
Speaker 1: the Sun, like in the eighteen hundreds were looking at
22:38
Speaker 1: the light that comes from the Sun and they noticed
22:40
Speaker 1: something really weird when they looked at the spectrum, Like
22:43
Speaker 1: they took the light from the Sun and they asked,
22:44
Speaker 1: what is the wavelength of all the photons that we get.
22:47
Speaker 1: That's sort of the spectrum, and it peaks in the
22:49
Speaker 1: visible range as you expect, But there's also one particular line,
22:54
Speaker 1: this green line from the Sun at a very strange
22:57
Speaker 1: wavelength that they couldn't explain. The only way to explain
23:00
Speaker 1: this line, The only thing that tends to give off
23:02
Speaker 1: light at this particular frequency is a weird form of iron,
23:06
Speaker 1: iron that's been ionized thirteen times. So iron has like
23:11
Speaker 1: twenty six protons and twenty six electrons, and in extremely
23:15
Speaker 1: hot situations, it can get so ionized that it loses
23:19
Speaker 1: thirteen of its electrons. So this is iron thirteen plus
23:24
Speaker 1: and this is capable of making that green line. But
23:26
Speaker 1: it only exists in situations that are super duper hot,
23:30
Speaker 1: like multimillion degree plasmas. So they spotted this in eighteen
23:34
Speaker 1: sixty nine and it was a real puzzler. Yeah, it
23:37
Speaker 1: tells us that the corona of the Sun is a
23:39
Speaker 1: lot harder than the surface of the Sun. And now,
23:41
Speaker 1: to give pe pose some context, I think you maybe
23:43
Speaker 1: mentioned that the corona is It's like the Sun is
23:47
Speaker 1: about one point four million kilometers. Why, but the corona
23:52
Speaker 1: extends eight million kilometers around the Sun, right, It's like
23:56
Speaker 1: a much wider circle that they call the corona of
23:58
Speaker 1: the Sun. That's right. And if you just like had
24:01
Speaker 1: a hot blob of gas around the Sun, that was
24:03
Speaker 1: hotter than the Sun, than that heat would flow in
24:05
Speaker 1: it would cool down. This is not like an equilibrium situation.
24:09
Speaker 1: In order for this to persist, you need some source
24:12
Speaker 1: of heat. But if the source of heat is the
24:14
Speaker 1: Sun itself, you would expect it to be hotter in
24:16
Speaker 1: the core. So really nothing about this makes sense. There
24:20
Speaker 1: needs to be some way to heat the corona, and
24:22
Speaker 1: it doesn't seem like it can come from the inside, right,
24:26
Speaker 1: And so it's a very strange situation. Somehow heat seems
24:29
Speaker 1: to be flowing out, violating the second law of thermodynamics,
24:32
Speaker 1: from something cooler, which is the surface of the Sun,
24:35
Speaker 1: to the corona, which is hotter. Right. He doesn't usually
24:38
Speaker 1: flow from a cooler surface to a hotter surface, right. Well,
24:41
Speaker 1: there's some subtleties. I think then maybe we need to
24:43
Speaker 1: go over like, for example, you're talking about temperature, not
24:46
Speaker 1: overall energy, Like the corona is hotter than the surface
24:50
Speaker 1: of the Sun, but it's a lot sparser. So this
24:52
Speaker 1: is one of those situations where it's like it's not
24:54
Speaker 1: like there's more energy outside of the Sun, it's just
24:56
Speaker 1: that the particles that are there are moving fast for
25:00
Speaker 1: than the particles at the surface of the Sun. Right,
25:03
Speaker 1: that's exactly right. It's much less dense than the surface
25:06
Speaker 1: of the Sun, but the temperatures are higher. In the
25:08
Speaker 1: same way that you can have very high temperature plasmas
25:11
Speaker 1: between galaxies, places where if we dropped you without a
25:15
Speaker 1: space who you would instantly freeze. Though technically you're in
25:18
Speaker 1: a very high temperature plasma. It's just very dilute. So
25:21
Speaker 1: there are fast moving particles, just not very many of them.
25:24
Speaker 1: So I think the same thing is true here. The
25:26
Speaker 1: corona is definitely hotter than the surface of the Sun.
25:29
Speaker 1: They're faster moving particles, but they're not as many of them,
25:32
Speaker 1: so there is less energy. Yeah, but it's still kind
25:35
Speaker 1: of I guess the mystery is like, why are these
25:37
Speaker 1: particles around the Sun moving faster than the particles just
25:41
Speaker 1: coming off of the Sun, Right, that's kind of the mystery. Yeah,
25:44
Speaker 1: exactly where did they get this energy? Because by a
25:47
Speaker 1: standard heat diffusion process, that shouldn't happen. You shouldn't get
25:50
Speaker 1: this weird spike where things suddenly get hotter further from
25:54
Speaker 1: the source of the heat. Now, could it just be
25:56
Speaker 1: like a situation where it's just the gas around the
25:58
Speaker 1: Sun is absorbing the heat from the Sun and getting
26:02
Speaker 1: that heat building up, you know, like kind of like
26:05
Speaker 1: if I put a black blanket around a light bulb,
26:08
Speaker 1: but it's gonna get hot. It is gonna get hot,
26:10
Speaker 1: but it's not going to get hotter than the light bulb. Right,
26:13
Speaker 1: That's the weird thing that's happening here. The air is
26:16
Speaker 1: already a blanket around the light bulb, and it doesn't
26:18
Speaker 1: get hotter than the light bulb. The heat diffusion equations
26:21
Speaker 1: tell you that the heat flows from the higher temperature
26:24
Speaker 1: to the lower temperature. So you need something else to
26:26
Speaker 1: explain this. You need some way to like pump energy
26:29
Speaker 1: out from the Sun, some other kind of process, not
26:32
Speaker 1: just diffusion of energy, all right, So that's a huge mystery.
26:36
Speaker 1: There are also other mysteries about the solar wind. Yeah,
26:39
Speaker 1: this is sort of connected in the sense that there
26:41
Speaker 1: are mysterious high speed particles. The solar wind is something
26:45
Speaker 1: that actually is kind of well named because when you
26:47
Speaker 1: think about a wind on Earth, you're thinking about like
26:49
Speaker 1: high speed particles pushing on you, bouncing off you, transferring
26:53
Speaker 1: their momentum. Well, the solar wind is sort of similar.
26:56
Speaker 1: The Sun doesn't just put out photons, it also puts
26:58
Speaker 1: out particles, protons, electrons, all these things moving at very
27:03
Speaker 1: very high speeds, like hundreds of kilometers per second. So
27:07
Speaker 1: this is what we call the solar wind, and it
27:08
Speaker 1: flies out through the whole solar system. Right, you get
27:11
Speaker 1: the solar wind even out here on Earth, and it's
27:13
Speaker 1: far out of Jupiter and Neptune. It's like it's not
27:15
Speaker 1: just light, it's actual like stuff flying from the Sun. Right. Yeah,
27:19
Speaker 1: the Sun is sort of throwing itself at us. This
27:22
Speaker 1: is one reason people say that we're sort of in
27:24
Speaker 1: the atmosphere of the Sun, because we are in this
27:27
Speaker 1: envelope of gas that the Sun is basically produced and
27:30
Speaker 1: it's sitting in the middle of Yeah, so then what's
27:32
Speaker 1: the mystery about the solar wind. The mystery is how
27:35
Speaker 1: the solar wind gets so fast, Like a four hundred
27:38
Speaker 1: kilometers per second is very very high speed for these particles.
27:43
Speaker 1: If you build a model of the Sun and just
27:45
Speaker 1: think about like particles at the edge of the Sun
27:48
Speaker 1: boiling off based on the temperature of the Sun, then
27:51
Speaker 1: you don't get particles this high speed. Like the Earth
27:54
Speaker 1: has an atmosphere, right, and it's losing its atmosphere because
27:58
Speaker 1: things at the very top of the atmosphere are moving
28:00
Speaker 1: at high speeds and gravity is lower, and they just
28:02
Speaker 1: sort of like fly off they reach escape velocity. So
28:05
Speaker 1: the Earth is boiling off hydrogen the same way the
28:07
Speaker 1: Sun is boiling off particles of itself. But if you
28:11
Speaker 1: do the calculations and predict how fast those particles should
28:14
Speaker 1: boil off, you get like a hundred and fifty kilometers
28:17
Speaker 1: per second, But what we see are things like four
28:20
Speaker 1: hundred kilometers per second. So there's some mechanism we don't understand.
28:24
Speaker 1: It's like accelerating these particles over a really short distance
28:28
Speaker 1: just from like the surface of the Sun boom out
28:30
Speaker 1: through the corona and out into the rest of the
28:32
Speaker 1: Solar system. You're saying the solar wind is faster than
28:36
Speaker 1: what you would expect. Now, is that related to also
28:39
Speaker 1: why the corona is harder, Because the corona beaming harder
28:42
Speaker 1: also means that the particles there are moving faster than
28:44
Speaker 1: what we expect. Yes, we think that these might all
28:47
Speaker 1: be connected mysteries, and the answer to them might lie
28:50
Speaker 1: somehow in the magnetic fields, because Sun isn't just a
28:54
Speaker 1: hot ball of gas the way the Earth is has
28:56
Speaker 1: very very powerful magnetic fields that are driving is happening
29:00
Speaker 1: inside of it, and also that are driven by what's
29:03
Speaker 1: happening inside of it. And these mathetic fields contain a
29:05
Speaker 1: lot of energy. And so if essentially you're getting little
29:08
Speaker 1: pumps or these magnetic fields are breaking, then those are
29:11
Speaker 1: various theories we have about how these particles might get
29:14
Speaker 1: accelerated really fast. And it also might explain how the
29:18
Speaker 1: corona is getting heated so much cool Now, you mentioned
29:22
Speaker 1: solar cycles before the cycles that the Sun goes through.
29:25
Speaker 1: There are some mysteries about that too. Yeah. I think
29:27
Speaker 1: this is one of the most incredible mysteries in the
29:30
Speaker 1: solar system, which is that the Sun's magnetic fields flips. Right,
29:34
Speaker 1: I mean, it blew my mind when I learned that
29:36
Speaker 1: the Earth's magnetic fields flips. First of all, that it
29:39
Speaker 1: isn't just static. It isn't just like point the same direction,
29:41
Speaker 1: like wanders around a little bit, but that every fifty
29:44
Speaker 1: thousand years or million years, it changes direction. North becomes south,
29:48
Speaker 1: south becomes north. If that's not weird enough for you,
29:51
Speaker 1: the Sun does that also, but it doesn't like clockwork.
29:54
Speaker 1: Every eleven years it flips. I can't overstate how much
29:58
Speaker 1: energy is involved here because the song one is enormous
30:01
Speaker 1: and whatever is causing its magnetic fields are very very powerful.
30:05
Speaker 1: For that entire thing to flip over, it's like turning
30:08
Speaker 1: a football stadium upside down, right, and it does it
30:12
Speaker 1: every eleven years. Yeah, it's pretty amazing. And so you're saying,
30:15
Speaker 1: we don't quite know why they flip, or we don't
30:18
Speaker 1: know what's causing it to flip every eleven years. Both,
30:21
Speaker 1: we don't even know why it flips. We don't know
30:24
Speaker 1: why the Earth's magnetic field flips either. But we definitely
30:27
Speaker 1: don't know why the Sun's magnetic field flips, and we
30:29
Speaker 1: don't know why it's so regular. We have a bunch
30:32
Speaker 1: of different theories for why the Sun's magnetic field flips,
30:34
Speaker 1: some of which are pretty awesome and hilarious. Is it
30:37
Speaker 1: like an eleven year old kid at the switch, just
30:39
Speaker 1: going click click click click, click click plick. I don't
30:43
Speaker 1: think eleven year old kids are that regular over a
30:46
Speaker 1: seven hundred million year timeline. It's amazing. The first thing
30:50
Speaker 1: to understand is how you get a magnetic field anyway.
30:52
Speaker 1: For the Earth, we think it comes from like motion
30:55
Speaker 1: of fluid metals inside the Earth. Right, Essentially, you're having
30:59
Speaker 1: the flow of charge particles creates a magnetic field that
31:02
Speaker 1: pushes the charged particles. You get more flow, which gives
31:05
Speaker 1: you more magnetic field. It's called the dynamo. And we
31:08
Speaker 1: have a whole podcast episode about where the Earth's magnetic
31:10
Speaker 1: field comes from. It might be that the Sun's magnetic
31:13
Speaker 1: field also comes from something similar. But these dynamos, these
31:17
Speaker 1: flows of plasma within the Sun could be affected by
31:20
Speaker 1: other things. Like for example, it could be that gravity
31:24
Speaker 1: from the other planets like Jupiter and Saturn and even
31:27
Speaker 1: the Earth are tugging on these things, and as they
31:30
Speaker 1: move around the Sun, their collective gravity could like create
31:33
Speaker 1: an instability which flips the whole thing over. Yeah, it's
31:36
Speaker 1: like a giant generator basically inside of the Sun and
31:39
Speaker 1: the Earth where you have like a all these kind
31:42
Speaker 1: of like magnetic materials kind of swirling around and creating things.
31:45
Speaker 1: And so I guess if the overall flow changes and
31:48
Speaker 1: the overall magnetic field changes to Another possibility is that
31:51
Speaker 1: it could be due to differential rotation. Like the Sun rotates,
31:55
Speaker 1: but it doesn't rotate the same speed all over. It's
31:58
Speaker 1: not a firm object the way the Earth is, right,
32:01
Speaker 1: and so for example, at the equator, it takes about
32:03
Speaker 1: thirty five days for the Sun to rotate, and it's
32:05
Speaker 1: twenty five days to rotate closer to the polls, And
32:09
Speaker 1: so the magnetic field lines might be getting like twisted
32:12
Speaker 1: and pinched, and it might take like eleven years for
32:15
Speaker 1: enough tension to build up for everything to sort of
32:17
Speaker 1: like snap and reassemble upside down. That's another possibility. And
32:22
Speaker 1: there's a third possibility for what might be explaining the
32:25
Speaker 1: Sun's weird magnetic field, which is that the plasma currents
32:29
Speaker 1: inside the Sun that are generating these magnetic fields might
32:32
Speaker 1: be moving sort of like in a huge donut of plasma.
32:35
Speaker 1: Like imagine not just a donut, but a donut now
32:38
Speaker 1: with layers in it. Like what do they call that
32:40
Speaker 1: when you have a croissant and a donut together, a chronut, right,
32:43
Speaker 1: So imagine a donut with all these layers in it.
32:45
Speaker 1: And every eleven years, instead of these plasma currents going
32:48
Speaker 1: sort of around the outside of the donut, they flip.
32:51
Speaker 1: So now they're going like around the short side of
32:54
Speaker 1: the donut. Briefly before it's flipping around and going the
32:56
Speaker 1: other direction. So we have like lots of very different
33:00
Speaker 1: weird ideas about what's going on inside the Sun, and
33:03
Speaker 1: the problem is we just haven't gotten close enough to
33:05
Speaker 1: make the measurements we need to understand what's going on. Yeah,
33:09
Speaker 1: because it is pretty hard to get close to the Sun,
33:12
Speaker 1: as I think Icarus and his father learned, it's hard
33:16
Speaker 1: to touch the Sun, and obviously also a little bit
33:18
Speaker 1: dangerous because the Sun is so hot and putting out
33:21
Speaker 1: so much radiation and light and heat. And so let's
33:23
Speaker 1: get into what it takes to build the spacecraft to
33:26
Speaker 1: get that close to the Sun to solve some of
33:28
Speaker 1: these mysteries. But first let's take another quick break. All right.
33:44
Speaker 1: We're talking about the Parker Solar Probe, which is the
33:48
Speaker 1: fastest or it's going to be the fastest moving spacecraft
33:51
Speaker 1: that humankind has ever built, and it's also going to
33:54
Speaker 1: get closer to the Sun than anything we've ever build.
33:56
Speaker 1: Some say it made it's sort of in a way
33:59
Speaker 1: touches the Sun. That makes me think of that kid
34:02
Speaker 1: on a Christmas story who puts his tongue on the
34:04
Speaker 1: life post and gets it stuck. Yeah, it does sound
34:06
Speaker 1: like a cautionary till the people who try to touch
34:10
Speaker 1: the Sun. Yeah, and I love this description of it
34:12
Speaker 1: as the fastest thing ever built, and that sounds really
34:15
Speaker 1: impressive until you kind of hear the number is going
34:17
Speaker 1: to go zero point zero six four of the speed
34:20
Speaker 1: of light relative to the Sun, and that's really really fast.
34:24
Speaker 1: It's like six thousand kilometers per hour, six hundred and
34:29
Speaker 1: ninety kilometers per hour. Thousand kilometers per hour. That is insane, right, because, um,
34:38
Speaker 1: as you go down the highway, you're going at like
34:40
Speaker 1: a hundred kilometers per hour. Does is six kilometers per hour? Yes,
34:45
Speaker 1: it's much much faster than I hope any of our
34:47
Speaker 1: listeners are traveling on their commute. But it's also such
34:50
Speaker 1: a tiny fraction of the speed of light, just another
34:54
Speaker 1: sense for like how vast the universe is and how
34:57
Speaker 1: extreme the conditions are out there, and how like quiet
35:01
Speaker 1: and cozy things are in our neighborhood. It's still a
35:03
Speaker 1: pretty amazing achievement. And it's also a huge achievement to
35:06
Speaker 1: send something that close to the Sun because the Sun
35:10
Speaker 1: is hot, like it's hot here on Earth, Like if
35:13
Speaker 1: you stand in the sun in the desert, maybe you're
35:16
Speaker 1: going to get heat through, but we're millions of kilometers
35:19
Speaker 1: away from the Sun. Imagine being like super close to
35:21
Speaker 1: the Sun, You're just getting so much more of the
35:23
Speaker 1: radiation and heat and particles trying to kill you. Right. Yeah,
35:28
Speaker 1: it's a very intense environment and, as you say, an
35:30
Speaker 1: incredible technological achievement to build a spacecraft that can survive
35:34
Speaker 1: these visits. Yeah. Do you know how they did it? Yeah,
35:37
Speaker 1: they have a bunch of like really cutting edge thermal
35:39
Speaker 1: engineering advances. They have a complex solar shield. Basically, the
35:45
Speaker 1: thing is diving towards the Sun, but most of the
35:47
Speaker 1: instruments are protected by a shield. So the thing is
35:50
Speaker 1: like diving towards the Sun, but it's doing a sort
35:52
Speaker 1: of shield first. Behind that shield are a bunch of instruments,
35:56
Speaker 1: and the shield itself is very fancy and very technological.
36:00
Speaker 1: It's made of two panels of reinforced carbon composite with
36:04
Speaker 1: like a carbon core foam, and a lot of really
36:07
Speaker 1: complicated engineering and modeling went into like how to bleed
36:10
Speaker 1: this energy off, how to make sure that the stuff
36:13
Speaker 1: behind the shield doesn't get fried. Yeah. I think if
36:16
Speaker 1: you look at a picture of the park or solar probe,
36:18
Speaker 1: you'll see that like half of it is basically the
36:20
Speaker 1: heat shield. It's almost like you know, like when Captain
36:23
Speaker 1: America jumps out of a building and he's you know,
36:26
Speaker 1: it's covered behind his shield. That's kind of what this
36:28
Speaker 1: probe is doing. It's it's not that it's covered all
36:31
Speaker 1: the way around. It just has a one shield in front,
36:33
Speaker 1: and so it's always going to be facing the Sun
36:36
Speaker 1: with the shield, otherwise it's gonna get fried. Yeah, and
36:38
Speaker 1: the shield can withstand temperatures up to like thirteen or
36:41
Speaker 1: fourteen hundred celsius, but the instruments have to be kept
36:45
Speaker 1: at like thirty celsius otherwise they'll get fried. And you know,
36:49
Speaker 1: this is a complicated maneuver. It's not just diving towards
36:52
Speaker 1: the Sun and done as you said, it's orbiting the
36:54
Speaker 1: Sun a bunch of times, so has to orient itself
36:56
Speaker 1: to always keep the shield between the instruments and the Sun.
37:00
Speaker 1: So that means like turning right. If these things are
37:02
Speaker 1: exposed to the intense radiation near the Sun for like
37:06
Speaker 1: tens of seconds, they're fried. So over like a ten
37:10
Speaker 1: year mission, you can't have ten seconds of exposure to
37:14
Speaker 1: the Sun. So this thing has a lot of computing
37:17
Speaker 1: on board to make sure that the shield is always
37:20
Speaker 1: in place. They call it one of the most autonomous
37:23
Speaker 1: spacecraft ever flown. Because it's so far away that like
37:26
Speaker 1: nobody on Earth can drive it in real time. It
37:28
Speaker 1: would take too long for the signals to get back
37:31
Speaker 1: and forth. So basically has to fly itself. And it
37:33
Speaker 1: doesn't just have to fly by itself because it's far away.
37:36
Speaker 1: It's because it's at some point it goes behind the sun, right, like,
37:39
Speaker 1: at some point it's on the other side of the Sun,
37:42
Speaker 1: and there's like no way it can send a signal
37:44
Speaker 1: to us or we can send a signal to it,
37:46
Speaker 1: so it has to be pretty much autonomous and always
37:50
Speaker 1: face the shield towards the Sun. Yeah, that's a really
37:52
Speaker 1: good point. We cannot control anything on the other side
37:55
Speaker 1: of the Sun. No signals we send could be received there.
37:58
Speaker 1: So every time it goes behind the Sun, we just
38:00
Speaker 1: sort of sit and wait and hope that it comes
38:03
Speaker 1: back around the other side in good condition. Yeah, they
38:06
Speaker 1: told me that. Apparently there are three computers on board,
38:09
Speaker 1: and the way that the probe makes decisions is that
38:12
Speaker 1: the three computers are independent and they vote on what
38:16
Speaker 1: the probes should do at any point when it's independent,
38:18
Speaker 1: and then they take a vote and whoever whichever decision
38:21
Speaker 1: wins gets the most votes. Is what the probe does.
38:24
Speaker 1: That's awesome. Are they all running Windows? No? I think
38:27
Speaker 1: one of them is like iOS. When of them to
38:30
Speaker 1: Linux or unux, just to be safe, you know, would
38:34
Speaker 1: download the Windows computer. But it's also interesting because like
38:37
Speaker 1: the probe needs to shield itself from the sun when
38:39
Speaker 1: it's closed because the sun is so hot. But when
38:41
Speaker 1: it's far away from the sun, it meets the Sun's
38:44
Speaker 1: energy to power and its batteries. So it has like
38:47
Speaker 1: these retractable solar panels that when it's far away from
38:51
Speaker 1: the sun, it like puts out these panels, but when
38:53
Speaker 1: it's getting closer, it tucks them in, kind of like
38:55
Speaker 1: one of those jets that tucks its wings in. Yeah,
38:59
Speaker 1: it's like a hawk diving right as it gets to
39:01
Speaker 1: very high speeds, it tucks itself in. It's really very awesome,
39:05
Speaker 1: and my applause to everybody who worked on this project
39:07
Speaker 1: and designed it. And it must be really nail biting
39:09
Speaker 1: to see actually out there and flying and implementing the
39:12
Speaker 1: programming that you put into it and trusting these autonomous
39:16
Speaker 1: systems to make these decisions with your baby. I mean,
39:19
Speaker 1: you work on this project for like a career. This is,
39:22
Speaker 1: you know, not a one project you work on and
39:24
Speaker 1: then you move on to another one the next week.
39:26
Speaker 1: This is a decades long project. So these people are
39:29
Speaker 1: biting their nails every time it goes around the Sun. Yeah,
39:32
Speaker 1: it's a lot of trust to put into or a
39:35
Speaker 1: majority vote, but you know, to get answers to the
39:38
Speaker 1: physics questions that we want, you really do have to
39:41
Speaker 1: get near the Sun. Sometimes you can learn things about
39:43
Speaker 1: what's happening really far away just by sampling the photons
39:46
Speaker 1: that get here, but sometimes they're scrambled, and that's the
39:49
Speaker 1: case here. To understand what's going on in the Sun's corona,
39:51
Speaker 1: in the acceleration of the solar wind and the magnetic field,
39:54
Speaker 1: you have to get as close as possible to the
39:56
Speaker 1: Sun because things tend to get scrambled by the time
39:58
Speaker 1: they're already here on Earth. And so part of what
40:01
Speaker 1: the probe is doing is getting those measurements really close
40:04
Speaker 1: to the Sun, which we know it's really hard, but
40:06
Speaker 1: they seem to be doing it. And so the idea
40:08
Speaker 1: is to, as you said, to study the electromagnetic field
40:11
Speaker 1: to the Sun because maybe that's where a lot of
40:13
Speaker 1: these mysteries can be explained. Yeah, they have a bunch
40:16
Speaker 1: of instruments on board. One of them measures the electromagnetic fields,
40:19
Speaker 1: another one measures the velocity of the particles of the
40:22
Speaker 1: solar wind, and there's also a camera they can just
40:24
Speaker 1: like take pictures of solar activity. Um. But it's this
40:27
Speaker 1: one that like measures the electromagnetic fields that I think
40:30
Speaker 1: is really going to provide the clues that help us
40:33
Speaker 1: understand and build like a deeper model of what's going
40:36
Speaker 1: on inside the Sun, because fundamentally, the Sun is a
40:39
Speaker 1: ball of plasma. Remember, a plasma is just a gas
40:42
Speaker 1: that's so hot that the electrons are free, they're flying around,
40:46
Speaker 1: so everything in the plasma has an electric charge. So
40:50
Speaker 1: instead of just being like any other blob of hot gas,
40:52
Speaker 1: now affected by electromagnetic fields and it generates electromagnetic fields.
40:57
Speaker 1: So it's very chaotic. It's very difficult to understand this
41:00
Speaker 1: part of why fusion is so hard to do here
41:02
Speaker 1: on Earth, because plasmas are chaotic and very intense, and
41:06
Speaker 1: so measuring those electromagnetic fields close up will give us
41:09
Speaker 1: a sense for like what's going on inside the Sun.
41:12
Speaker 1: How are these things flipping? Are these magnetic tubes like
41:14
Speaker 1: reconnecting and snapping to accelerate particles. That really is part
41:18
Speaker 1: of the core of the mission of the spacecraft. Yeah, because,
41:20
Speaker 1: as you mentioned before, the maybe the sort of two
41:23
Speaker 1: big mysteries about the Sun that we don't know right now.
41:26
Speaker 1: Why the outside of the Sun, the solar corona is
41:29
Speaker 1: hotter than the surface of the Sun. And also what
41:32
Speaker 1: is making the solar winds so fast, faster than it
41:35
Speaker 1: should be if it was just coming off of the Sun.
41:37
Speaker 1: And so it seems like maybe a big explanation is
41:39
Speaker 1: what's going on with the magnetic fields outside of the
41:42
Speaker 1: Sun right exactly, And it might be connected to another mystery,
41:47
Speaker 1: which is the mystery of these solar flares. You know,
41:49
Speaker 1: the Sun is bright and hot, but it's not always static,
41:52
Speaker 1: right There are suns spots and sometimes it injects a
41:55
Speaker 1: lot of energy and even like huge blobs of plasma.
41:58
Speaker 1: These things are called coronal massage actions and solar flares,
42:01
Speaker 1: and something we want to understand because it affects life
42:03
Speaker 1: on Earth, because these particles sometimes even reach Earth and
42:06
Speaker 1: can damage our electronics. And they think that these solar
42:09
Speaker 1: flares might be caused by disruptions in the magnetic field
42:13
Speaker 1: of the Sun. Like when these magnetic tubes get pinched
42:16
Speaker 1: off and collapse, it can cause a little eruption. That's
42:19
Speaker 1: an idea for what might be explaining these solar flares,
42:21
Speaker 1: and a related idea might solve these questions of the
42:25
Speaker 1: solar wind and the heat of the corona. As you
42:27
Speaker 1: were saying this, this theory of like nanoflares that instead
42:31
Speaker 1: of like always having huge, big flares, maybe the Sun
42:34
Speaker 1: is constantly having a lot of these little magnetic disruptions
42:38
Speaker 1: that caused nanoflares that dump out energy from the surface
42:41
Speaker 1: of the Sun to the solar wind and to the corona. Yeah,
42:45
Speaker 1: because I think an interesting concept here is that the
42:47
Speaker 1: Sun isn't just the gas that's on fire. It's not
42:51
Speaker 1: just the circle that's shining bright kind of like part
42:54
Speaker 1: of the Sun is also the invisible magnetic fields that
42:58
Speaker 1: the Sun is creating, and that it's there are extending
43:01
Speaker 1: out past a visible surface, right, because these magnetic fields
43:04
Speaker 1: are huge, right, they are there are millions of kilometers
43:08
Speaker 1: more wider than the actual visible width of the Sun,
43:12
Speaker 1: Like it has invisible fingers. Yeah, and it's sort of
43:16
Speaker 1: like a duet, right, or like a dance. There's two
43:19
Speaker 1: partners there. The magnetic fields push on the particles and
43:23
Speaker 1: change how they behave and where they go and how
43:25
Speaker 1: much energy they have. And the particles, because they have charges,
43:29
Speaker 1: also generate electric fields. It's this very nonlinear behavior that
43:33
Speaker 1: can easily generate runaway effects that can get very very extreme,
43:37
Speaker 1: and they power each other, like these dynamos inside the
43:40
Speaker 1: Sun or inside the Earth that generate our magnetic field.
43:43
Speaker 1: And so, as you say, this like one partner in
43:45
Speaker 1: that dance that we can't always see directly with our eyes,
43:48
Speaker 1: but it plays a really big role in what's happening.
43:51
Speaker 1: It controls how all this plasma flows and where the
43:54
Speaker 1: energy is deposited. And so instead of just thinking about
43:57
Speaker 1: the sun is like a hot ball of gas where
43:59
Speaker 1: the energy is diffusing out from the second law of thermodynamics. Instead,
44:03
Speaker 1: now we're imagining like all these little magnetic tubes that
44:06
Speaker 1: are like leaching energy out from the Sun more intensely,
44:09
Speaker 1: and those could be like heating up the particles and
44:11
Speaker 1: speeding them away in the solar wind to get them
44:14
Speaker 1: really really fast and making the corona hot as well. Yeah,
44:18
Speaker 1: because the other thing is that it's kind of like
44:19
Speaker 1: a dynamic environment around the Sun, right, like, the Sun
44:23
Speaker 1: is churning, things are moving, like you said before, Uh,
44:26
Speaker 1: there are flows inside of the Sun of these particles,
44:30
Speaker 1: and the stuff in the Sun is changing and flowing
44:33
Speaker 1: and churning, and so these magnetic fields outside of the
44:36
Speaker 1: Sun are also moving and changing, and sometimes they crash
44:39
Speaker 1: into each other. And that's kind of I think one
44:41
Speaker 1: of the other explanations for maybe what makes the corona
44:44
Speaker 1: so hot is that these magnetic fields are basically crashing
44:47
Speaker 1: and exciting the corona more than you would think. Yeah,
44:50
Speaker 1: and it's Eugene Parker who sort of came up with
44:52
Speaker 1: this idea. Before him, people thought about the Sun's atmosphere
44:56
Speaker 1: sort of like static, the way the Earth's is. It's,
44:58
Speaker 1: you know, maybe boiling off a little bit at the top,
45:00
Speaker 1: but it's basically just floating there, held by gravity. But
45:03
Speaker 1: he wrote the first paper suggesting that the Sun's atmosphere
45:06
Speaker 1: is could of dynamic and has all these magnetic components
45:09
Speaker 1: and generates this really powerful wind to explain these high
45:13
Speaker 1: speed particles. And his original paper was like rejected a
45:16
Speaker 1: million times, sort of like the way like the Harry
45:19
Speaker 1: Potter manuscript was rejected by dozens of people before it
45:22
Speaker 1: was published, but he was right, and it was confirmed
45:24
Speaker 1: later by like the Mariner mission that measured the solar
45:27
Speaker 1: wind to be these really high speed and so, yeah,
45:29
Speaker 1: the Sun's atmosphere is much more complex in the Earth's
45:32
Speaker 1: atmosphere because it's a big magnetic ball of hot plasma.
45:35
Speaker 1: Is lots of crazy things happening. These magnetic tubes are
45:38
Speaker 1: breaking and clipping and reversing and smashing into each other.
45:41
Speaker 1: It's like magnetic weather. Yeah, it's good that his theory
45:44
Speaker 1: finally saw the light of day. But I think also
45:47
Speaker 1: that could also maybe explained the solar wind. Right, it
45:49
Speaker 1: could be these like thrashing, moving magnetic fields around the
45:54
Speaker 1: Sun that are maybe causing or accelerating particles in the
45:58
Speaker 1: solar wind. Yeah, these are all mechanism sums for taking
46:01
Speaker 1: energy from the inside of the Sun and dumping it
46:04
Speaker 1: out into the corona, accelerating those particles into the solar
46:07
Speaker 1: wind and heating up the corona. Remember, to solve this mystery,
46:10
Speaker 1: we need something other than just the second loftterm agynamics.
46:13
Speaker 1: We need some pump that's like pulling energy from the
46:15
Speaker 1: Sun and accelerating these particles. And as you say, these
46:18
Speaker 1: magnetic fields and they're crazy behavior might just do that.
46:22
Speaker 1: And early results from the Parker Solar Probe are suggestive.
46:25
Speaker 1: They've made a bunch of measurements of these magnetic switchbacks,
46:28
Speaker 1: like sudden reversals in the magnetic field, much more dramatic
46:33
Speaker 1: than anything you would expect otherwise. They're like frequent and
46:36
Speaker 1: short lived changes in the magnetic field. That's suggesting that
46:40
Speaker 1: it's sort of like a chaotic magnetic environment. And these
46:43
Speaker 1: magnetic pumps, these nanoflares at the surface of the Sun
46:47
Speaker 1: caused by this crazy magnetic behavior could be with heating
46:50
Speaker 1: up the corona and accelerating the solar wind. Yeah. I
46:53
Speaker 1: think that was the whole point of the Parker Solar Probe,
46:55
Speaker 1: is to get in there, in those magnetic fields and
46:58
Speaker 1: measure what's going on in there. And that's kind of
47:00
Speaker 1: what they mean when they say that probe kind of
47:02
Speaker 1: touches the Sun because it's it's sort of in there.
47:05
Speaker 1: It actually gets to the point where it's right in
47:07
Speaker 1: the middle of those magnetic fields, which in a way
47:10
Speaker 1: are kind of the Sun itself, right. I mean, it's
47:12
Speaker 1: not touching the visible surface of the Sun, but it
47:15
Speaker 1: is touching it's magnetic fingers. Yeah, when you're building a
47:18
Speaker 1: model of the Sun, you have to match the data
47:20
Speaker 1: you see from the outside, but it's always ambiguity about
47:22
Speaker 1: what's going on inside. So which you really want is
47:25
Speaker 1: data from the inside, from where all the action is happening,
47:28
Speaker 1: right from the inside out. As you say, Parker is
47:30
Speaker 1: going to give us this measurement of what's going on
47:32
Speaker 1: very very close to the Sun and can help us
47:34
Speaker 1: constrain these models, tell us which ideas are wrong and
47:37
Speaker 1: which ideas do actually describe what's happening in the Sun.
47:40
Speaker 1: So that's pretty exciting in a way. It's sort of
47:42
Speaker 1: like the probe is not really touching the Sun. It's
47:44
Speaker 1: more like it's getting to the point where the Sun
47:46
Speaker 1: touches it. Touched by the Sun. That's going to be
47:51
Speaker 1: the name of its memoir when it's done with its trip,
47:53
Speaker 1: and hopefully it didn't make it's a heat shield out
47:55
Speaker 1: of wax and feathers, because we know that's a bad idea.
48:00
Speaker 1: And there's also exciting room for surprises. Right, we have
48:03
Speaker 1: these ideas about what might be happening inside the Sun
48:05
Speaker 1: and near its edge, but remember that every time we
48:08
Speaker 1: send something out into the universe or develop a new
48:11
Speaker 1: kind of eyeball. We're surprised by what we learned. The
48:13
Speaker 1: universe doesn't just say yes or no to our theories.
48:16
Speaker 1: It says yes but or actually, something totally different is happening.
48:21
Speaker 1: And so the Parker Solar Probe is going somewhere nobody's
48:24
Speaker 1: gone before, and it might discover things that totally surprise us.
48:28
Speaker 1: The universe is not big into improv theory. It's not
48:31
Speaker 1: a yes and kind of thing. It's a yes, but
48:35
Speaker 1: it's a sorry about the theory you've been developing for decades,
48:38
Speaker 1: but you were totally wrong. Well that's when we have
48:40
Speaker 1: to improvise. I guess all right, Well, the probe is
48:43
Speaker 1: out there, it's flying close to the Sun. Uh. There's
48:46
Speaker 1: data coming in all the time now and new papers
48:49
Speaker 1: coming out of it, and so as it gets even
48:51
Speaker 1: closer to the Sun, we'll learn more and more about
48:53
Speaker 1: what's going on in there, and so stay tuned for
48:56
Speaker 1: more news about the Sun. I'm saying that pro has
48:59
Speaker 1: a lot of any days ahead of it, exactly, And
49:02
Speaker 1: so thank you to everybody at NASA who developed these
49:05
Speaker 1: things and sweated over it and launched it so that
49:08
Speaker 1: we could all learn more about what's going on at
49:11
Speaker 1: the heart of our solar system. Yeah, and thanks to
49:13
Speaker 1: the scientists who talked to me to make my comic
49:15
Speaker 1: about the Parker Solar Probe and all of this solar signs. Again,
49:19
Speaker 1: if you want a visual companion to this episode, just
49:21
Speaker 1: google PhD Comics and Parker Solar Probe. You'll see it
49:26
Speaker 1: on Physics Magazines website. All right, well, we hope you
49:29
Speaker 1: enjoyed Dad, Go out there and get some sun if
49:31
Speaker 1: you can. Thanks for joining us, See you next time.
49:41
Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain
49:44
Speaker 1: the Universe is a production of I Heart Radio. For
49:47
Speaker 1: more podcast from My Heart Radio, visit the I Heart
49:50
Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your
49:54
Speaker 1: favorite shows.