This video taken in 2022 captures the fall of a satellite into the ocean off Puerto Rico.

49 American satellites were launched in the effort to form an international communications network,

but they began falling after just four days, with around 40 plummeting from space.

Responsible for their descent were the massive solar flares on the Sun's surface,

which brought about geomagnetic storms on Earth.

In the ionosphere, an electrically charged part of Earth's atmosphere,

at a height of 60 km or more above the surface, magnetic storms occur.

The atmosphere is heated and expands,

which is thought to increase air drag on satellites and limit their speed, causing them to fall.

Solar activity changes constantly, exerting a variety of effects over life on Earth.

When a large geomagnetic storm occurs, it can cause damage to electronic devices, like communication satellites,

interrupting access to services such as the internet and television.

Additionally, magnetic storms can disrupt the Earth's magnetic fields,

causing sudden power surges, that inflict damage on power transformers.

Massive power outages can occur.

The functionality of the social infrastructure is placed at severe risk by these sporadic occurrences.

Countries and regions around the world hurry to predict and prepare for the threat of "space disasters."

The Japanese government is making one such effort, using space weather forecasts.

For today's forecast, we report "Active" for one day.

Space weather is a natural phenomenon, so to some extent it's inevitable.

But just as warnings allow us to take actions to avoid tsunamis, if we had space weather warnings...

I think we'd be able to reduce or avoid damage from it.

However, the sun remains shrouded in mystery, with many details of its mechanisms still unknown.

Given a better understanding, increases in solar activity could be predicted more accurately.

Solar activity varies in strength over the course of an approximately 11-year cycle.

As of June 2024, that cycle happens to be reaching its peak.

It presents the ideal opportunity to pursue the unknown properties of the sun.

As we research how the Earth is affected by external factors...

I think that research of solar flares will be of growing importance.

In this program, we follow the researchers exposing the mysteries of the sun,

in order to prevent potential space disasters.

The National Institute of Information and Communications Technology, or NICT,

is the only institute in Japan capable of space weather forecasts.

2:30 PM.

Each day at this time, they conduct their forecast meeting.

Based on the solar data they've compiled, they discuss the appropriate forecast for the next 24 hours,

with regard to phenomena such as solar flares and geomagnetic storms.

First, the researchers check their data.

Satellites observe the speed and temperature of various particles emitted by the sun.

Their data is received 24 hours a day in four countries, including Japan.

Around the sunspots detected on the Sun, massive explosions occur frequently.

These are solar flares.

With them, strong x-rays and other electromagnetic radiation, as well as high-energy particles, are emitted.

From the sun's outermost atmosphere, the corona, clusters of ionized gas called plasma, explode outward.

The particles released from the Sun in this phenomenon can have a damaging effect on organic life.

Following a solar flare, electromagnetic waves reach the Earth as x-rays in approximately 8 minutes,

while the fastest high-energy particles arrive in 30 minutes.

Then, superheated clusters of corona gas reach the Earth in 2 to 3 days.

The Earth's magnetosphere and atmosphere form a barrier,

that prevents these forces from acting directly on the planet's surface.

However, large flares cause greater impact than the Earth can be shielded from,

creating disruptive geomagnetic storms.

At the NICT, solar observation data and other information is used to simulate

how the plasma and magnetic fields may reach the Earth, rating its expected affect.

At the center is the sun, with the Earth displayed beside it.

Blue areas indicate where the solar particles are slow, and yellow areas where they're somewhat faster.

Serving as the leader of the space weather forecasting team is Takuya TSUGAWA.

When the boundary between the fast and slow speed of gas reaches the Earth...

The Earth's magnetic field can be greatly disturbed.

When clusters of plasma reach the Earth at very high speeds, shockwaves ensue.

The impact of these shockwaves on the planet then threatens to spread geomagnetic disruption.

This system calculates when it'll reach the Earth, and with how much of an effect.

This shows a forecast for about a week in advance.

It lets us determine around how far ahead there's an effect.

Researchers specializing in a variety of fields

hold discussions to determine the space weather forecast for the next 24 hours.

Magnetic field strength should increase, so issue a K4 warning.

They discuss whether the intensity of geomagnetic variation, ranked from 1 to 10, should be rated a 4, "Active."

The higher the number, the greater the indication of magnetic disturbance.

As for today's forecast...

If it continues until night, will it stay at 4?

A few days ago, gas expelled from the corona reached the Earth,

and affected its magnetic fields, bringing some cause for concern.

If the magnetic field strength increases similarly to last time, I think it should be a 5.

A 5? Understood.

Today's report indicates that magnetic field intensity of solar winds has increased slightly:

Geomagnetic activity is expected to be at an active level for one day.

The forecast is released on their website,

with warning levels issued in 7 categories, related to solar occurrences like flares, the magnetosphere, and the ionosphere.

The information is also distributed by email to about 7,000 registered users,

including wireless communications companies and positioning service companies.

Actually, the number of solar flares and their intensity scale have increased dramatically each year.

Social impacts such as effects on satellites and telecommunications are readily apparent.

We'll need to remain cautious of it.

This graph shows the number of solar flares that have been observed.

Although more than 4,000 occur in active years, some years see nearly none.

The number varies with a wave-like shape.

One solar cycle occurs roughly every 11 years.

Since 2020, they've been on the increase.

The pattern demonstrates that, as of 2024, the solar cycle is reaching its peak.

In 2022, Tsugawa's team announced the worst-case scenario for extreme space weather events.

It's a simulation of an occurrence at a scale likely to happen only once a century.

It suggests that if major solar flares continued over a two-week span,

widespread power outages would be caused throughout Japan.

For those two weeks, transmissions and broadcasts would be interrupted, leading to chaos within society.

Due to the rapid onslaught of electromagnetic waves from the Sun,

frequencies would be temporarily restricted.

Some cell phones would be rendered completely inoperable.

The long-distance radio communications of ships and planes would also be affected.

Some radio waves, such as shortwave frequencies, are able to reach the other side of the globe,

by being reflected in the ionosphere, which is located above the stratosphere.

However, powerful solar x-rays would sharply increase the electron density in the lower ionosphere,

causing shortwave to be absorbed.

This would make long-range radio communication useless.

Electromagnetic waves from the sun would inflict damage on monitoring radar,

causing flight and ocean shipping stoppages globally.

Operations plans would be thrown into total disarray.

The satellites that form the core of global communications

would take serious damage from electronic equipment malfunctions and sudden power surges.

Most satellites would sustain damage,

halting dependent services, like satellite communications and weather forecasts.

Likewise, instability in the ionosphere would impede the propagation of radio waves from positioning satellites,

making it impossible to accurately locate current positions.

As a result, systems making use of satellite positioning such as car navigation, automated driving, and drone flight,

would all become inaccurate by tens of meters.

There's no need to hold excessive fear.

However, I think it's important that we understand the impact and prepare for it.

The accuracy of space weather forecasts is currently around 70%.

The team seeks to bring this up to 80%, the typical accuracy of terrestrial weather reports.

In order to accurately predict the coming of solar flares and magnetic storms,

comprehension of the mechanisms that trigger them is a necessity.

However, many aspects of solar activity remain shrouded in mystery.

At the National Astronomical Observatory of Japan,

Yukio KATSUKAWA observes solar flares and sunspots, in order to decode these mechanisms.

This is the Solar Flare Telescope used by the observatory to examine solar flares.

It views the entirety of the sun.

We use it daily on days with clear weather.

This lets us get a handle on typically unpredictable solar flares.

This is the observation room, where data from the solar flare telescopes is collected.

Three kinds of telescopes are used to effectively grasp solar activity.

By observing the diverse types of light and magnetic fields emitted from the Sun,

detailed activity can be more accurately glimpsed.

The telescopes accurately capture the moment that flares are emitted.

They can be expanded for a closer view.

In order to make observations without influence by the atmospheric or weather fluctuations,

that are unavoidable on the Earth's surface, they make use of a special tool:

the satellite Hinode.

It's equipped with an 0.5-meter Solar Optical Telescope, that is one of the most advanced in the world.

This is an image taken from Hinode.

When the small sunspots are expanded upon,

they can be viewed with minute detail, as if peering through a microscope.

Since the Sun is seen through the void of space, the view provided is extremely stable and accurate.

Hinode can even clearly observe magnetic fields.

The left image shows sunspots photographed with visible light.

At the right, a special method is used to reveal magnetic fields.

The white areas are north pole fields, and the black ones, south pole fields.

Although they appear entirely black through visible light,

Hinode is able to pick up the polar distinctions.

Looking before a sunspot is formed,

the area is dotted with countless pairs.

When many of them appear together, it's an indication that a large sunspot will soon form there.

99 percent of solar activity is actually caused by magnetic fields.

That's why we consider observation and measurement of the fields to be the most important thing.

Both the Earth and the Sun are, in a sense, giant magnets.

However, their magnetic field lines couldn't be more different.

The lines for the Earth form a simple shape between the north and south poles,

while solar magnetic field lines are complex and chaotic.

This is due to the rotation of the Sun.

Being mostly made of gas, the sun's rotation period varies with latitude,

from around 32 days near the poles, to 27 days near the equator.

As a result, the magnetic field lines are pulled by the fast equatorial rotation,

which coils up inside the Sun like a spindle of thread.

As the field lines coil, they become more and more powerful,

with some eventually bursting outside the surface of the Sun.

The cross-sections of these protruding lines are seen as sunspots.

This image is a detailed obervation of a sunspot's magnetic fields.

The pink arrows represent the directions of magnetic field lines.

It seems clear where the magnetic fields are strongly twisting, like a whirlwind.

In doing so, their energy is stored up to large extents.

These serve as the triggers for flares.

Their explosive release of energy can be predicted from our observations.

The magnetic fields of the sunspots provide the energy source for solar flares.

Large-scale flares are often glimpsed with ribbon-like shapes.

When a flare occurs, that area glows very brightly.

This happens when the atmosphere around the sun is heated to extreme temperatures.

Instantly changing the energy of magnetic fields to heat or kinetic energy...

That's the power of solar flares.

The mechanism with which solar flares release plasma and cause magnetic storms has also been made clear.

This footage uses x-rays to view the Sun's outer atmosphere, the corona.

First, magnetic field lines connecting the sunspots are visible.

When the flare occurs, a ring is formed.

This release of plasma, the cause of magnetic storms on Earth, was captured by Hinode.

Flares are caused when the magnetic field lines between the north and south poles reconnect.

These reconnecting lines caused an important and unique flare that was observed with x-rays.

This is how it happens.

A magnetic field line forms a loop between sunspots.

The lines hold plasma within them, so at this point it's still on the Sun's surface.

But, when the magnetic strength on the surface grows stronger, the field lines are drawn out.

Lines are pulled together, and make contact.

The lines converge, forming a ring and being expelled along with the plasma.

This important moment was preserved on film.

Since its launch in 2006, Hinode has been operational for 18 years,

more than one full solar activity cycle of 11 years.

This accumulated data is of extraordinary value.

The National Astronomical Observatory of Japan has performed its globally unique form of solar observation for over 100 years.

Katsukawa endeavors to use the collected observational data

to establish the principles of solar activity, making these mechanisms clear.

This would in turn serve as the gateway to providing highly accurate space weather forecasts.

Katsukawa first became interested in the Sun as a middle-school student.

He received a telescope,

and as his free study during summer vacation, he sketched out the position of sunspots.

Watching during summer vacation, sometimes I'd see a lot, and sometimes less.

That constant change was exciting to me.

With ever-deepening interest in outer space, he chose to study astronomy.

As a graduate student,

he learned that Japan's satellites had been delivering some of the world's most impressive results in solar observation,

and he decided that he wanted to make an active contribution to the field,

joining the development team of the solar optical telescope for Hinode.

However, it was no easy task.

Outer space is a totally different environment from Earth, in zero gravity.

The presence of gravity on Earth affects telescopes there slightly.

We had to simulate the environment of space and make sure it would function the same.

Those experiments and tests were very challenging for us.

Every test brought with it new issues.

Many unanticipated problems arose, such as heat-related warping,

but Katsukawa worked persistently to resolve them, one by one.

In 2006, Hinode was launched.

There's a door on the telescope, and after its launch, opening the door would let the sun's light in.

Looking through the telescope for the first time, the sun's image appeared very sharply.

On its surface, we could easily see the granulation of the convective pattern.

When I saw the images, I was astounded by them.

The start of Hinode's mission marked the beginning of Katsukawa's career as a solar physicist.

He's also hard at work in the development of advanced observational equipment.

Currently he's involved in the international SUNRISE project,

using a stratospheric balloon, which launches in June of 2024.

It's all covered up.

Researchers in Sweden, from where the balloon will be launched, relay their progress.

The lower part is the SCIP.

Telescopes and observational devices, developed in countries such as Japan, Germany, and Spain,

have been assembled to undergo performance testing.

In the project, a balloon containing a telescope and other equipment will be launched from Sweden.

After ascending to the stratosphere over the course of three hours,

the balloon will cross the Atlantic Ocean, moving over Canada.

During that time, it will spend around one week observing the Sun.

Around the north pole at the time of the summer solstice, the sun doesn't set.

The midnight sun continues to shine.

This makes solar observation possible 24 hours a day.

As the peak of the solar activity cycle is neared,

it's the perfect chance to glimpse major flares.

The telescope to be used for the project exceeds even Hinode's capabilities,

with a diameter twice as large, at a full meter.

Since it can monitor a wide range of wavelengths of light,

its accuracy in reading magnetic fields is extremely high.

They seek to measure the magnetic fields of the chromosphere,

the solar layer located between the photosphere and the corona.

This is footage of the chromosphere taken by Hinode.

Gas is emitted from its surface at high speeds.

However, Hinode lacks the capabilities to gauge its magnetic fields.

The chromosphere changes constantly, and magnetic field energy is released.

To grasp how the fields cause this, we intend to equip SUNRISE with a near-infrared observation unit.

I hope that by measuring magnetic fields at the brightest points...

We can visualize how magnetic field energy becomes heat energy.

If the magnetic field activity of the chromosphere can be grasped,

it'll provide more detailed insight into the internal activity of the Sun.

Katsukawa is also participating in the development of a new solar observation satellite, SOLAR-C,

which is scheduled to launch in 2028.

SOLAR-C is expected to realize seven times the observational accuracy of Hinode,

using ultraviolet rays to measure solar magnetic fields in great detail.

As for how it is that magnetic field energy affects the flow of plasma, there's much we don't know.

Reconnections in magnetic fields occur, but their scale is actually very small.

SOLAR-C seeks to analyze those minute properties.

If SOLAR-C can be mobilized during the peak of the solar cycle,

the mechanisms of solar activity that it reveals may allow us to prepare for the possibility of space disasters.

Tsugawa believes that if research on solar activity progresses,

applying its findings will enable faster and more accurate forecasts of space weather.

He's also using AI to analyze the large quantity of accumulated data,

in order to create an assistive system for forecasts.

Things like predictions and forecasts can still be very difficult.

There are things we don't know physically, and things that require academic research.

It'll be interesting to take on that challenge.

Without knowing about the other side or interior of the sun, we won't truly understand space weather.

That's why I think it's most important that we can research those areas.

To life on Earth, the Sun represents both the beginning of life and the potential to end it.

Understanding its mysteries is key to preparing for the possibility of space disasters.