Original subtitles

(mysterious music)

- [Narrator] Two advanced space probes

are now orbiting the sun, one from NASA,

the other from Europe.

They have begun studying our star up close,

imaging the mechanisms of hot plasma and magnetic fields,

even diving into its atmosphere, discovering new insights

into the solar winds and the science of the stars.

(adventurous music)

(air whooshing)

(pensive music)

This is the Royal Observatory of Belgium in Brussels.

Scientists have been studying the sun from here

for over a hundred years using telescopes like this.

The observatory is also the World Data Center

for the Sunspot index.

It is now receiving data from the European Solar Orbiter,

a wealth of information studying the sun up close,

well within the orbit of the planet Mercury.

The imagery alone is spectacular,

giving us a whole new perspective

of our sun and the nearest star.

- It sometimes happens, I get into my office,

I download the latest data, and I stare for hours that it,

it's so addictive, actually. (laughs)

Nobody has ever seen the details of the corona

in that much detail before.

So every time we get an image down,

it's the first time we see something

at that scale, and that's really fascinating,

it's really a discovery space that we're entering.

- I was personally blown away by the quality

and degree of detail in these images.

And clearly, as solar physicists, we've been

looking at images of the sun for many years,

but by going three times closer,

we can get the spatial resolution up by a factor of three,

and we see things that we haven't seen before,

and that's of course the beauty of science,

to explore the unexplored.

- [Narrator] The journey of Solar Orbiter began in 2020,

and has traveled over two and a half billion kilometers,

with gravity assists from Venus and Earth.

- The spacecraft is performing very well,

and we are very happy about that,

because it is the first time that it had to go

so close to the sun, and so it is

a very challenging environment,

and of course, the spacecraft is designed for it,

but this design is all based on modeling, on predictions.

So you only really know that it's going to work

until you have seen it working.

- Solar Orbiter is basically a research mission,

but ultimately, we want to be able to predict space weather.

These are energetic events that could have an impact

on high tech installations on Earth,

GPS satellites, power grids, and we want to make sure

that in the future, we can predict geomagnetic storms

based on solar activity.

And for that we really need to take the sun's temperature

and measure the solar wind and connect the two.

By going close to the sun, we try to capture

the physics of space weather events,

and we want to film on sun the events

that give rise to changes in the near-Earth environment.

And we need to fly close to the sun

to be able to measure the solar wind

while it's still in a pristine, undisturbed state.

(ominous music)

- [Narrator] One of the great mysteries of the sun

is the difference in temperature from its surface

to its atmosphere, where it increases by a million degrees

in a process that is not yet understood.

Generation of the high speed solar winds

emanating from the star is another process under scrutiny

- For the mission, it's important in many ways,

because on one hand, of course, the closer you go,

the better resolution you get and the more

details you can see.

And it's also important because we want to understand

the influence of the sun on planets, on the Earth,

and for that we want to come closer

and we want to see what's happening

and at the same time feel around the spacecraft

how the environment is changing.

- So the EUI, so the extreme ultraviolet imager,

sees the hot corona, so so to speak,

the atmosphere of the sun, at extremely high resolution,

much higher than what we had before.

And one of the problems that we're after

is to understand why the corona is so hot.

It's like a million degree or so

while the surface of the sun is 5000, something like this.

And that's really puzzling, and we're after that

since decades.

And we think that it's possibly

because of tiny, tiny, tiny eruptions

that go on all the time, but that are

too small to be seen by other instruments,

and now that we, with our meter,

we get so close to the sun, we can finally see them.

And we did see a lot of them in the first images

that we took, and the closer we get, the more we see.

So we are really excited about this,

because we may finally be on the solution

to that decade long problem.

- These measurements that the spacecraft is taking now

and also later will be important to improve

our understanding of the sun.

One of the things we want to understand better

is how the sun affects the Earth,

but for that you have to really understand

how the activity of the sun is cost,

how it evolves, and when, for example,

such a cloud of solar material leaves the sun,

how it also propagates through space

and goes towards the Earth.

So for that, we want to do several of those close passages

to the sun to observe it from close by,

and we also want to change the orbit of the spacecraft

so that it can see the solar poles,

because we have never ever seen those before,

and they are important to understand

the magnetic field of the sun.

(solemn music)

- [Narrator] The Solar Orbiter carries 10 instruments

on board, imagers of various frequency,

including an x-ray spectrometer

and extreme ultraviolet imager,

a magnetometer, energetic particle detector,

and a solar wind analyzer suite.

It also carries a radio and plasma wave suite,

which measures electric and magnetic fields

around the spacecraft.

- So now, the whole payload is working together.

It's actually a lot of work to coordinate all that,

but what that gives us is that we get

a comprehensive diagnostics of the solar plasma,

of the solar atmosphere, so we can,

with EUI, get the dynamics and the fine scale structure,

but then with other instruments like SPICE,

we can get measurements of the temperature

of the density, these kind of things.

So with all the instruments together,

we get a comprehensive view and understanding

of the physics, and then you have

all the institute instruments also

that we're working with that will

help us understand what the corona mass ejections are

and how they influence the physics of the heliosphere,

which is the surroundings of the sun, so to speak.

- By having all 10 instruments

on Solar Orbiter operate together,

we can really harness the entire power of this mission,

which is designed to connect remote sensing observations

of the sun, meaning pictures and spectra,

and what you measure, essentially feeling the solar wind

as it flies past the spacecraft.

And for that we need all 10 instruments,

and they have now all been tested and exercised

and tuned like musical instruments.

And so this is the first time we actually

got all 10 working together as a team.

- So this Solar Orbiter and the instruments on it,

it's a new machine that we are bringing to place

in the space that has never been visited before.

So when we do that, we cannot expect everything

to work as it is designed or is expected.

There is a steep learning curve to learn to operate a thing,

and that's what we call commissioning phase.

And we are now at the end of that phase

and we have learned how to operate our machine

to the best of its capacities,

and the results are actually fabulous.

- It's important to have all the instruments working

and operating in a coordinated way,

because one of the main goals of the mission

is to link the sun and its activity with the environment,

and not only the environment close by, but also the planets.

And for that we want to look at the sun's activity,

the solar activity, with many different telescopes

that look at it in different wavelengths,

so that means they are looking at different layers

in the atmosphere, and they can also measure things

like the magnetic fields on the sun.

And then at the same time, we also have instruments

at the outside of the spacecraft

that will sense and and measure what's happening

around the spacecraft itself.

So whenever there's solar activity,

we can feel the effects close to the spacecraft.

- Among the things that we now see for the first time

are really tiny sources of energy released in the corona,

and we are now very curious to find out

in what sense they're connected to the large scale structure

of the solar wind and the energy that gets essentially

put into the flow of particles towards Earth.

And we try to really use models to connect

what we see on the surface to what we see in the wind,

and that is something that clearly takes more time

and investigation to really pinpoint

where a solar wind package came from,

that we believe that we've done quite well

in terms of pointing at the right place,

and thereby we hope to get this complete picture

of cause and effect.

(tense music)

Close approach of Solar Orbiter to the sun,

to about a third of the distance between sun and Earth,

is so important because it allows us

to get measurements of the solar wind

in an almost pristine state before it gets mixed

on its way to Earth.

And more importantly, to combine these measurements

with pictures of the sun and spectra

that we can then connect and get

a complete picture of the sun and solar wind.

- [Narrator] Scientists are also studying

the dangerous solar storms that affect Earth.

- This first perihelion was clearly

our first scientific milestone

after getting all the instruments calibrated.

So this really gives us good confidence

that we'll be able to do this again,

and we'll do it roughly twice a year

when we fly by the sun again.

In between we'll be far away from Earth,

so that takes a lot of time to get the data downloaded.

But in between these far away periods,

we have also close by periods where we can

dump all the data that we've accumulated

and then it's Christmas for the scientists

to look at the data and get new scientific insights.

(pensive music)

- [Narrator] The Parker Solar Probe is the second spacecraft

now operating close to the sun.

It was launched by NASA in 2018,

and has taken four years and several gravity assists

to reach its operational orbit.

(pensive music)

Its elliptical orbit bringing it closer

and closer to the star's corona,

a boundary layer not clearly understood.

This project has been over 50 years in the making.

- The fact that the sun is hot has been

a major technological challenge

and why it's taken us so long to fly Parker Solar Probe.

- That design of the heat shield,

where the front of the heat shield that faces the sun

is hot enough to melt aluminum,

but the backside, where the spacecraft electronics

and instruments are, is actually at room temperature.

That's been the key to getting this mission done.

- This is a dream come true.

One of the major goals for the Parker Solar Probe mission

is to fly through the solar corona,

and we are doing that now.

(tense music)

- [Narrator] The edge of the sun's atmosphere

is known as the Alfven critical surface,

a postulated zone where the solar wind

goes from a slow to extremely fast speed,

spreading out through the solar system.

The Parker Solar Probe has passed through this barrier

into the corona, showing that the boundary is indeed lumpy,

and has sampled material still bound to the sun.

(gas whooshing)

- Two of the most challenging scientific mysteries

in astrophysics occur in the region

that we call solar corona.

- [Narrator] The instruments on board have shown

that outside the boundary, the solar winds

accelerate away from the sun at high speed,

unable to fall back onto the surface.

However, inside the boundary, the magnetic field

is much stronger, and solar material is much slower,

tied to the surface.

- That we've always known that the atmosphere of the sun,

the corona, spins with the sun,

spins the same speed that the sun does,

but out at the Earth, the solar wind

is moving straight out from the sun,

so it's no longer spinning.

Where that transition happens is very important

for understanding, because that spinning of the corona

actually helps slow down the sun.

All stars get slower in their spinning as they get older.

Parker Solar Probe sees that transition

from spinning to straight happens further from the sun

than we thought.

And that actually has implications

for every star in the universe in how they slow down.

And that's important, actually, for the habitability

of solar systems around distant stars.

(pensive music)

- [Narrator] Gaining knowledge of our sun

will help us understand all the other stars around us.

This will help us with the search for habitable exoplanets.

Understanding the processes of the solar winds

and energetic particles will assist with finding worlds

that, like the Earth, have magnetic shielding

to help protect living organisms on the planet's surface.

- Parker Solar Probe is the first mission

to get close enough to sun to see

where the action is actually happening,

where the solar wind is accelerated,

where the corona is getting heated.

And we've seen a lot of new science

that we don't completely understand,

but there have been some remarkable results

about small events that we can see

with Parker Solar Probe that get smeared out

in the 93 million miles between the Earth and the sun.

- We are so excited for these new results

coming down from Parker Solar Probe.

Parker has gone closer to the sun

than we've ever gone before.

It's inside the orbit of Mercury.

We're seeing the solar atmosphere

as it emits its material out into the solar system.

We call that the solar wind.

And we're seeing this process up close and personal

at a higher detail and complexity

than we've ever seen before.

- Actually as it's being formed.

So we're able to study the solar wind

and all of its variability and complexity

up close like we just can't do from Earth.

(gentle music)

- [Narrator] The protective magnetic field surrounding Earth

is constantly buffered by solar winds

and energetic particles.

At the poles, these solar disturbances

create spectacular auroras.

It may also cause the atmosphere to leak out into space.

- So the sun not only has this constant solar wind

that blows out in all directions,

it has solar storms, solar flares,

and coronal mass ejections, and those energetic storms

can accelerate particles up to almost the speed of light,

and those energetic particles can actually cause

radiation sickness in astronauts

if they're out unprotected when those happen.

On the Earth, we're protected by the Earth's magnetic field

and the atmosphere of the Earth.

But once you're out in space away from

the Earth's magnetic field, those can be

a danger to not only astronauts, but also spacecraft.

- The sun is capable of energizing pieces of atoms

up to really high speeds and energies.

And these are damaging to astronauts and to electronics.

Now, we're protected down here on Earth

from these particles, but on the moon or beyond,

astronauts wouldn't have that luxury.

So one of the key missions of Parker Solar Probe

is to understand how these particles

are actually being accelerated

so that we can better predict and protect against them.

- [Narrator] Another phenomenon of our sun

deals with space dust and debris,

pieces that clump together by static electricity,

and then, as they grow by gravity,

there appears to be none close to the sun.

- Space dust is pieces of comets and asteroid debris

that fills our solar system, but close to the sun,

they can be so hot that they actually vaporize,

or that material can also be pushed away

by the radiation of the sun.

And so there ought to be a region

around the sun where there is no dust.

And for the first time, Parker Solar Probe

is seeing evidence of this dust-free zone.

(pensive music)

- So the sun goes from a quiet period,

what we call solar minimum to solar maximum and back again,

about every 11 years.

And we launched into a very quiet solar minimum.

That's actually helping this mission,

because during solar minimum, things are simple,

there aren't very many sun spots,

there aren't very many of these solar storms,

ones we're seeing are small, and that allows us

to individually identify every single event.

- And then later, as Parker continues to observe the sun,

we'll see this ramp up of activity and energy burst

and we'll be able to see the more complex

and bigger energy bursts.

(solemn music)

- [Narrator] In the coming years,

the probes will witness up close the power of the sun

during its more active phase as it spirals

closer and faster to the star.

- Parker Solar Probe is already

the fastest human-made object.

As it gets closer to the sun and spirals in

and goes faster and faster, it will reach

half a million miles an hour.

So we are so excited to see the results

as Parker continues on its mission.

- Before Parker Solar Probe passed through

the sun's Alfven boundary, it detected

kinks in the solar wind, where it would

momentarily double back on itself.

Scientists called them solar wind switchbacks,

but had no idea of the mechanism that caused them to form.

As Parker got closer and closer to the sun,

it detected more and more of these switchbacks.

It was able to track one of them to its origin

on the visible surface of the sun.

On the surface, you can see defined cells

as heat rose from beneath.

These convection cells churned and created funnels

of magnetic energy above the surface.

Scientists concluded that these switchbacks

form inside these funnels before rising

into the corona and beyond.

This is only one piece of the puzzle.

However, scientists still don't yet know how they form.

Over the next few years, Parker will keep looking for clues

as it explores our sun up close.

The sun is the only star we can study like this.

It is also the only star we know that supports life

on at least one of its orbiting planets.

Understanding it is critical as we search

for life beyond our solar system.

- That will link directly into the question,

are we alone in this universe?

And that is one of the biggest question

for humanity to answer.

(mysterious music)