Imagine you're on this spacecraft
and it's like whooshing towards the sun.
Oh wow.
At an unbelievable speed, like it's going so fast, you know?
Yeah.
And you're on this mission to figure out
all the secrets of our nearest star.
Yeah.
Big ball of plasma that's been like the giver of life
and energy for billions of years.
Amazing.
Welcome to Cosmos in a Pod, the space and astronomy series.
Yeah.
Please like, comment, share, and subscribe.
Yes.
So we've all seen the sun a lot, right?
I mean, it's like there every day.
Every day.
But how much do we really know about this,
like this big powerhouse in the sky?
Yeah, it's an interesting question.
Today we're going deep into the heart of the sun.
Ooh.
Exploring its structure, all the mysteries it holds,
and the incredible missions that are helping us
unravel its secrets.
It's gonna be a fascinating journey.
I think so.
One that's full of surprises.
Okay.
You see, the sun, it's not just this like static
ball of fire just hanging there.
Right.
It's dynamic, it's always changing.
Right.
With layers upon layers of activity and complexity.
Okay, so let's break this down a little bit.
When we look at the sun, what are we really seeing?
Well, what you see is the photosphere.
Okay.
The sun's visible surface.
Right.
But it's not a solid surface like we have here on Earth.
Oh, okay.
It's a layer of crazy hot plasma
about 6,000 degrees Celsius.
Wow.
And that's where most of the sun's light comes from.
Okay, so it's kind of like the tip of the iceberg.
Exactly.
That's a whole lot more going on underneath.
Oh yeah, absolutely.
Beneath the photosphere, there's this vast
and really intricate interior.
Oh yeah.
Starting with the convective zone.
Okay.
This is where hot plasma rises, cools,
and then sinks back down.
It creates this churning motion
that carries energy up towards the surface.
This is like a giant boiling pot constantly stirring.
Yeah, that's a great way to think about it.
I like that.
And as we go deeper, we get to the radiative zone.
This is super dense and energy can take
like hundreds of thousands,
even millions of years to travel out.
Wow, that's a serious traffic jam of energy.
Yeah.
Okay, so we went from the photosphere
through the convective zone
and now we're in the radiative zone.
What's next?
What's at the very heart of the sun?
At the very center of it all is the core.
Okay.
The sun's nuclear furnace.
Here, the pressure is immense,
temperatures over 15 million degrees Celsius.
It's hot.
And this is where hydrogen atoms fuse into helium,
releasing all that energy that powers the sun.
It's mind-blowing to think that that process,
that fusion has been going on for billions of years.
I know.
And it'll keep going for billions more.
It's incredible, the power and the longevity of our star.
Yeah.
But you know what's really fascinating?
All that energy made deep within the core.
Yeah.
It has to travel through all those layers we talked about
before it gets to us here on Earth.
So it's a journey of epic proportions.
It is.
In terms of both distance and time.
And as we've learned more about the sun's interior,
we've run into some really puzzling questions.
Oh.
Yeah, and one of the biggest is the coronal heating problem.
Oh yeah, I've heard of this.
Yeah.
It's the mystery of why the sun's outer atmosphere,
the corona, is millions of degrees hotter than the surface.
Right.
It seems kind of counterintuitive, doesn't it?
It really does.
You'd think the further you get from the heat source,
the cooler it would get.
Right.
But the sun, it's the opposite.
Yeah.
The corona, that wispy outer layer,
can reach temperatures of over a million degrees Celsius.
Wow.
While the photosphere where all that energy starts
is only around 6,000 degrees.
So how do scientists explain that?
Well, there are a few theories.
OK.
Some think that powerful magnetic waves made
in the sun's interior are funneling energy
up into the corona.
So like a cosmic elevator.
Exactly.
Lifting energy from the surface to that outer atmosphere.
I like that.
Others believe that tiny bursts of energy,
called nanoflares, are constantly
erupting on the surface.
OK.
And they're collectively heating the corona.
It's like a billion tiny explosions
going off all the time.
It is.
And then there's the solar wind, a constant stream
of charged particles shooting out from the sun,
which might also be contributing to the heating.
So there are a lot of possibilities.
Yeah.
But we're still working on the whole picture.
We are.
It's a complex problem, one that needs
a really deep understanding of the sun's magnetic fields,
plasma dynamics, and how energy moves around.
Yeah, it's amazing to think that this object,
we see it in the sky all the time,
still holds so many mysteries.
I know.
That's the beauty of science.
The more we learn, the more we realize how much more there
is to discover.
Right.
And the sun, our closest star, is a constant source
of wonder and intrigue.
Absolutely.
Speaking of discoveries, haven't we
sent probes to actually study the sun up close?
We have.
One of the most amazing missions is the Parker Solar Probe,
a spacecraft that's getting closer to the sun
than any other before it.
Wow.
How close are we talking here?
The Parker Solar Probe is flying through the sun's corona
within a few million kilometers of the surface.
That's insanely close to a star that's over 100 times
the diameter of Earth.
It is.
And it's moving at an incredible speed,
over 600,000 kilometers per hour.
It's the fastest human-made object ever.
Why does it have to go so fast?
That speed is vital for the probe to survive.
Oh.
It lets it dip in and out of the corona really quickly.
Got it.
Minimizing its exposure to the intense heat and radiation.
So like a daredevil skimming the surface of a raging inferno.
That's a great way to put it.
I try.
And even with those insane conditions,
the Parker Solar Probe is sending back some incredible data.
Oh, wow.
Giving us views of the sun's corona and solar wind
we've never seen before.
What kind of insights is it giving us?
Well, it's seen these strange zigzag patterns
in the sun's magnetic field.
OK.
They're called switchbacks.
Switchbacks.
Yeah.
And they might help explain how the solar wind is
generated and speeds up.
So it's basically rewriting how we understand the sun.
It is.
And it's just one example of the incredible missions
that are helping us unlock the secrets of our nearest star.
Yeah.
It's really amazing what we're learning.
So we've been talking a lot about the Parker Solar Probe.
Yeah.
And like it's amazing, right?
All the engineering that lets it get so close to the sun.
It's incredible.
But it's not the only tool we have for studying our star.
No, not at all.
So what other ways do scientists use to unlock the sun's secrets?
You're right.
The Parker Solar Probe is amazing,
but it's just one piece of the puzzle.
We've got a ton of instruments, both on the ground
and up in space.
OK.
It's giving us this multifaceted view of the sun.
So it's like having a team of detectives,
each with their own specialty.
Yeah, exactly.
Working together to solve the case.
Some of our most powerful tools are actually
ground-based solar telescopes.
OK.
These telescopes have really fancy filters and instruments
that let us observe the sun in all these different wavelengths
of light.
It reveals details we could never see with just our eyes.
So what kind of details are we talking about?
Well, we can see sunspots, those dark cooler patches
on the surface we talked about earlier.
We can also see prominences, these huge loops of plasma
that stretch out from the sun, sometimes
for hundreds of thousands of kilometers.
I've seen pictures of those.
They're incredible.
Oh, yeah.
They look like fiery arches just hanging in space.
They are quite a sight.
Yeah.
And then there are solar flares, those sudden bursts of energy
that release radiation across the entire electromagnetic
spectrum.
So ground-based telescopes, they give us that close-up look
at the surface.
They do.
And all the crazy events happening there.
But to really understand the sun,
we have to go beyond Earth's atmosphere.
OK.
And that's where space-based observatories come in.
Like the Parker Solar Probe.
Like the Parker, yeah.
But others, too.
One of the most important is the Solar Dynamics Observatory,
or SDO.
It's been orbiting the sun since 2010.
OK.
And what makes SDO so special?
It's like a solar watchdog, constantly watching
the sun in tons of wavelength.
Wow.
It takes pictures every few seconds.
Seriously.
Giving us this constant stream of data
about what's happening.
So it's like having a live feed of the sun's most exciting
moment?
Yeah, exactly.
That's awesome.
And SDO has given us so much information
about solar flares, coronal mass ejections,
and how the sun's magnetic field works.
So it's like we have front row seats to the sun's biggest
shell.
And then we have ESSOHO, the Solar and Heliospheric
Observatory.
OK.
It's been watching the sun from space since 1995.
So what does ESSO focus on?
Well, it's a multipurpose observatory.
OK.
But one of its big contributions is in helioseismology.
Hold on.
Helioseismology, what's that?
It's the study of the sun's interior, but using soundwaves.
Why?
Kind of like how geologists use seismic waves
to study the earth's insides, helioseismologists
use soundwaves to map out the sun's structure.
So we can actually see inside the sun using sound.
We can.
That's wild.
By looking at the patterns of those soundwaves,
we can learn about the sun's density, its temperature, what
it's made of at different depths.
So it's like taking an ultrasound of the sun.
Yeah.
That's a great analogy.
It's revealing all these hidden layers.
And ESSO, it's totally revolutionized
how we understand the sun's interior,
helping us see the processes that drive all that activity.
Seems like we have this impressive toolbox
for studying the sun.
We do.
And these tools are always getting better and more
precise, giving us more detailed and insightful views
of our star all the time.
It's not all just for scientific curiosity, though, right?
Yeah, definitely not.
I mean, understanding the sun has real implications for us
here on Earth.
Absolutely.
The sun is not just some faraway object.
It's this powerful force that can
have a massive impact on our planet and everything we use.
We talked about solar storms before
and how they could mess up our power grids and communication
systems.
Right.
And those storms, they start on the sun.
And they can travel so fast through space,
reaching Earth in just a few hours or days.
So the more we learn about the sun and how it acts,
the better we can prepare for those storms.
Exactly.
And maybe even lessen their impact.
By monitoring the sun's activity and creating better forecasting
models, we can give people early warnings about potential storms.
So it's about understanding our star, not just
for the knowledge itself, but for our own safety.
It is.
The sun gives us life and energy,
but it can be dangerous, too.
By studying it carefully, we can learn
how to live with it, using its benefits,
and protecting ourselves from any harm.
OK, so we've talked about the structure of the sun,
the different layers, and all the amazing missions
helping us understand it.
But what about all those crazy events we see on the sun?
Right.
Those huge bursts of energy and eruptions of plasma.
Can we zoom in on those a bit?
Oh, definitely.
We're talking about sunspots, solar flares, coronal mass
ejections.
They're not only visually stunning,
but they give us clues about the sun's magnetic field
and how it affects us here on Earth.
OK, so let's start with sunspots.
Yeah.
I remember seeing pictures of those as a kid,
those dark patches on the sun.
What are they exactly?
Imagine these massive magnetic knots on the sun's surface.
They're so strong, they actually stop the heat from below
from getting to the surface.
Oh, wow.
So a sunspot, it's actually a region that's
cooler than its surroundings.
That's why it looks darker.
So it's like a magnetic traffic jam blocking the heat.
Precisely.
And these sunspots can be enormous.
Some are even bigger than the entire Earth.
That's huge.
But they're not just sitting there, right?
Yeah.
They change over time.
You got it.
Sunspots go through these cycles of activity.
We call it the solar cycle.
It lasts about 11 years.
OK.
And during the cycle, the number of sunspots, it goes up,
it goes down.
And that affects how often we see other solar events too.
Like you mean the solar flares and coronal mass ejection.
Exactly.
Think of sunspots like the epicenters
for all these powerful events.
You know those tangled magnetic fields we talk about?
Yeah.
Sometimes they snap.
Oh, wow.
And when they do, they release just this massive amount
of energy.
And is that when we get a solar flare?
That's it.
A solar flare, it's like the sudden flash,
this burst of radiation across the whole electromagnetic
spectrum from radio waves to x-rays and gamma rays.
Wow.
And if a really strong flare is pointed right at Earth,
well, it can mess with our radio communications, GPS signals,
even damaged satellites.
That's intense.
OK, so what about coronal mass ejections, the CMEs?
Yeah.
They sound even more powerful.
OK, picture this.
A billion ton cloud of charged particles,
just this giant bubble of plasma,
launched into space at crazy speeds.
That's a CME.
Whoa.
It's like a solar tsunami caused by those snapping magnetic
fields.
So it's like sunspots are the warning signs.
Yeah.
Heads up, something big is about to happen.
Yeah, you could say that.
Sunspots are where the magnetic activity is really high.
Right.
And all that activity can lead to these explosive events
that can definitely affect us here.
It's kind of incredible and a little scary
how these little dark spots on the sun can cause so much stuff.
It really shows how connected everything
is in our solar system.
Yeah.
The sun's activity, it ripples through space,
affects everything in its path.
And the better we understand these events,
the better we can protect our tech and ourselves.
This deep dive has been amazing.
We've gone from the sun's core all the way to its corona.
We've uncovered some secrets and seen just how powerful it is.
Any final thoughts for our listeners?
I'd say remember this.
The sun isn't just some distant object.
It's what sustains life on Earth.
But it can also be dangerous.
Right.
By studying it, getting to know it,
we can learn how to live with it, appreciate its beauty,
but respect its power too.
That's a great point.
Thank you so much for taking us on this incredible journey
to the sun.
You're welcome.
And listeners, we hope you've enjoyed learning
all about our nearest star.
If you want to keep exploring space with us,
be sure to follow and subscribe to Cosmos in a Pod
and our YouTube channel.
Until next time, keep looking up and keep wondering.