The dark side of the sun

SOLAR FLARES HAVE GAINED A REPUTATION AS TROUBLEMAKERS, BUT WHEN LOOKING AT THEIR BEAUTY, IT'S POSSIBLE TO SEE THEIR LIGHT SIDE

 Illustration by  Tegan Iversen

Illustration by Tegan Iversen

The year is 1859.

The day is Thursday, the 1st of September.

Queen Victoria sits on the throne of England, and, just a few kilometres away from Buckingham Palace, Richard Carrington points his telescope towards the Sun and notices something unusual.

Carrington is an astronomer at the King's Observatory, spending his days meticulously tracking sunspots: cooler patches on the Sun's surface caused by the constantly circulating uneven gases that form the Sun. But on this fateful Thursday, he saw something remarkably different.

Instead of observing the usual dark blots on the flaming orange surface of the Sun he was accustomed to, Carrington instead saw "two patches of intensely bright and white light" that appeared to have broken away like a bubble, their "brilliance was fully equal to that of direct sunlight", as he would write later.

Such a strange occurrence as it was, Carrington thought there was an error with his telescope, that "a ray of light had penetrated a hole in the screen attached to the object-light". But Carrington's tools were in perfect working order.

Whatever explanation there was for his observation, this brilliant flash of light was heading toward Earth with full ferocity. And Carrington was not alone in noticing this phenomenon unfurling across the sky.

On the other side of the world, C. F. Herbert, tired after a long day panning for gold in rural Victoria, Australia, put down his billy of tea and stared at the sky in wonder. The bright twinkling constellations that he usually saw had been replaced by waves of colour, dancing and fading into each other.

  The lights of this aurora are stunning, but also capture the dance of incoming energised particles from the Sun that interact with the atmosphere to produce amazing light shows. Image c  aptured on June 24 2016 by Expedition 48 Commander Jeff Williams, on the ISS.   NASA    (Public domain)

The lights of this aurora are stunning, but also capture the dance of incoming energised particles from the Sun that interact with the atmosphere to produce amazing light shows. Image captured on June 24 2016 by Expedition 48 Commander Jeff Williams, on the ISS. NASA (Public domain)

Later he described the event: "Lights of every imaginable colour were issuing from the southern heavens, one colour fading away only to give place to another, if possible, more beautiful than the last."

Herbert had witnessed an astronomical event known as an aurora. This natural light display is usually confined to the areas around the poles, hence its other moniker, the ‘polar lights’. But on this evening, people across the globe from Australia to Argentina were all privy to this colourful symphony.

In the United States, a telegraph operator called Royce drew his hand sharply back from the telegraph in pain. The machine had given him a small electrical shock. Nothing too serious... but odd.

Three different locations around the globe, three different events. The brilliant flash of light, the beautiful aurora and the electrical anomaly seemed to exist separately. But as astronomers — including Carrington — would come to realise, the three are spectacularly linked.

History repeats itself

The year is 2003.

The day is the 31st of October — Halloween.

Homes and businesses across the entire country of Sweden are abruptly plunged into darkness for an hour.

Elsewhere, the ground team of the Solar and Heliospheric Observatory notice that their satellite has failed and NASA is also experiencing failures with their Advanced Composition Explorer satellite. As satellites and communication systems across the world shut down, beautiful waves of auroras are once again witnessed around the world.

These events were not well-timed Halloween pranks. They had the same modus operandi as the event of 1859 — something was happening on the surface of that Sun that simultaneously caused electrical problems and auroras. Just like serving cod oil with a spoonful of sugar, the Sun was serving the bad and the beautiful on the same plate in the form of a solar flare.

  This coronal mass ejection (CME) blew out from the Sun in 2013 in a glorious roiling wave, travelling at more than a million kilometres per hour.   Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams  (Public domain)

This coronal mass ejection (CME) blew out from the Sun in 2013 in a glorious roiling wave, travelling at more than a million kilometres per hour. Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams (Public domain)

Not black and white

Solar flares are shaping up to be an anti-hero on an astronomical scale.

Whilst there are villains specifically created to be universally despised or feared (personally, I still hate the man who killed Bambi's mother), the most enthralling villains on page and screen are those who are complex and multi-layered. At times, the nuanced nature of the character steps outside the boundaries of a villain. For a moment, they don the role of a hero or even a victim. Shakespeare's Othello, Darth Vader, and even Draco Malfoy could be called villains at some point in their stories, but at other times are complicated enough to elicit our sympathy or even love.

Solar flares have a similar character arc, with both a dark and a light side: a damaging, electricity-disrupting element, and yet also a tranquil, magical quality in the form of auroras. Describing solar flares in the terms ascribed to villains might be appropriate when assessing their damage, but undercuts their beauty, complexity, and mystery.

Let’s delve in to do a proper character study.

Before unravelling the mysteries of solar flares we first need to look at the Sun. Humans tend to think of the Sun as being reasonably consistent. It rises in the east and sets in the west, and even if we don't see it every day, we know that it is still there in the centre of the Solar System, burning away as it has been doing for billions of years and will continue to do so for billions more.

However, when you examine the chemical composition of the Sun, it is far from stable. It’s not a solid body like the Earth, with a core, mantle, and crust. Instead, the Sun is a giant ball of continually burning gas. Inside the heart of the Sun, hydrogen atoms smash into each other and fuse together, producing 386 billion billion megawatts of energy per second. This incomprehensible amount of energy is mostly in the form of light and heat.

The surface of the sun is no less violent; called the photosphere, it has a temperature of roughly 5800K (5526C), but if that’s too hot to handle, you can find a sunspot. Sunspots are aptly named as they look like dark spots on the surface of the sun and are significantly "cooler" than the surface: 2000C cooler to be exact (but that still makes them 3526C).

Above the photosphere is the chromosphere, which emits a low-density steam of charged particles known as a solar wind. Just like the wind on Earth, solar winds fluctuate throughout the year. Extending out of the photosphere, like streamers flapping in the breeze, are solar prominences.

These are no ordinary streamers — they’re loops of hot gas composed of charged hydrogen and helium atoms. When two solar prominences touch, they short-circuit and high energy photons and particles are rapidly released in the form of a solar flare. According to NASA, the energy in one solar flare is enough to power the entire United States for a million years.

In other words, an explosion occurs on the surface of a burning star that sends a billion tonnes of ionised gas straight for Earth.

Cool, right?

This explosion is what Carrington observed in 1859 and what wreaked havoc in 2003.

There are four categories of solar flares — B, C, M, and X — classified according to their strength. B and C type flares are too weak to affect the Earth. M type flares are ten times stronger, able to cause short radio blackouts at the poles and damage to astronauts on the International Space Station. But the biggest villains are the X type flares. The 2003 solar storm was caused by an X type flare so powerful it overloaded NASA’s instruments designed to detect such flares.

Although the idea of such an explosion is pretty terrifying, the good news is that the radiation emitted by solar flares is absorbed by the Earth's atmosphere. No humans on Earth have ever sustained any serious injuries due to the solar flares, but that doesn’t mean solar flares are a victimless crime — these attacks harm anything with wires. Solar flares contain different types of energy (one superweapon is never enough for a villain): heat energy, magnetic energy, and ionising radiation including X-rays and gamma rays. This ionising radiation damages satellites and interferes with electronic devices.  

So, this begs the question: what would happen if a solar flare the size of the Carrington event occurred today?

A world suddenly running blind

A solar flare produces a cloud of electrically charged particles that interfere with the Earth’s magnetic fields and can potentially short circuit electrical grids.

Back during the Carrington event in 1859 there were reports of electricity failures, but this didn’t pose much of a problem because most of the world was off-the-grid.

But imagine the irreversible damage if all the electricity in the world went out today.

Electricity is fundamental to modern life. Today, did you send emails or attend a conference call with colleagues? Did you use Google Maps or GPS? Are you reading this article right now on your phone or computer? In the case of a solar flare, these everyday actions would not be possible.

 
  If a powerful solar flare hit Earth, the sea of sparkling lights across the world could be extinguished.   NASA  (Public domain)

If a powerful solar flare hit Earth, the sea of sparkling lights across the world could be extinguished. NASA (Public domain)

 

Electricity does more than turn on the lights and charge your iPhone. Our lifestyle and society’s infrastructure have become reliant on it. Hospitals without electricity would be unable to run basic medical equipment and life support for patients. Transport would come to a standstill.

Also, consider the thousands of satellites in orbit around the Earth. During a solar storm, they would become engulfed in a hot cloud of charged particles in the upper atmosphere and slow down as if moving through a sandstorm. This drag would eventually plunge satellites back down to Earth.

If communications satellites are damaged then pilots wouldn’t be able to talk with the ground staff to know if it was safe to land. Cargo ships would be sailing without accurate directions and using celestial navigation as a substitute wouldn’t be a solution, as spell-binding auroras in the sky would block the light of the stars (it would be harder to appreciate auroras if you’re the captain of a hundred-tonne cargo ship sailing without GPS).

And on top of all this, world leaders couldn’t communicate with each other to attempt to stop situations from spiralling out of control.

Battling the light

These are just the immediate impacts. It would take months or even years to rebuild electricity grids.

It is estimated that another Carrington event could cost the world US$40 billion per day, and that number doesn't even take into account the lost economic productivity.   

And just when we thought we had a grip on all the superpowers of this villain, it pulls out another trick, because solar flares can also severely damage the ozone layer.

For two days after the Carrington event, high-energy protons entered Earth’s atmosphere at the polar regions, ionising nitrogen and oxygen to nitrogen oxides, which degraded ozone molecules. According to scientists, this degradation resulted in a 5% decrease in global atmospheric levels.

This number is startling in itself, but becomes downright scary when compared to the effects of chlorofluorocarbons on the ozone layer (the stuff that’s been putting a hole in the ozone layer for decades). In recent years, chlorofluorocarbons have reduced the level of ozone by 3%. So one event — one solar flare — can do more damage to the ozone layer in one moment than all the chlorofluorocarbons in the atmosphere combined.

The most terrifying thing of all? We have no way to stop or prevent this damage.  

Make no mistake — the beauty of the auroras caused by solar flares, the light side of our villain, will be short lived when the extent of the damage is felt.

Keep your friends close and your enemies closer

So, what are scientists doing to mitigate or minimise the damage caused by such flares?

Before trying to tackle solar flares, scientists are trying to understand what makes up a solar flare’s character.

Some of the questions they are hoping to answer include what a solar flare is and how it forms, in that hope that future events can be predicted. Solar activity fluctuates over an 11-year cycle, and observing this cycle over the past few decades has given us a better ability to track and predict the occurrence of such flares. According to the latest predictions, there is a 12% chance of experiencing a solar flare in the next decade.

In particular, the Solar Dynamics Observatory spacecraft has been used to better understand how the Sun behaves... and misbehaves. In October 2016, then-President Obama issued an executive order that directs many agencies, including NASA, to coordinate research and preventive efforts in the case of “space weather events, in the form of solar flares, solar energetic particles, and geomagnetic disturbances”.

NASA estimates that it will take eight minutes for a solar flare to hit earth, and so even with the best models and predictions, this doesn’t leave a lot of time for precautionary measures if a flare were to occur unexpectedly.

Solar astrophysicist Michael Wheatland at the University of Sydney says that a lot is being done to study solar flares: “There is a big investment, worldwide, in research in solar activity and space weather, in part because of the potential risk.”

He suggests that right now, the best thing we could do is to switch satellites and power networks into “safer modes” if a solar flare was headed to earth.

But steps are also being taken to pre-emptively mitigate any damage caused by a solar flare.

Satellite engineers are attempting to make satellites more robust and impenetrable to the short-circuiting that may occur when struck by a solar flare. The United States are also testing “available devices that mitigate the effects...on the electrical power grid” and implement such devices if successful, as well as rebuilding the power grid if necessary.

There are also many things that the average person can do if a solar flare is predicted and electricity is lost, such as filling containers with water and freezing them to keep food cold in the fridge, having a canister of petrol in the garage as petrol stations need electricity to power pumps, and investing in solar-powered or hand crank chargers to power up your phone. These small actions may make the situation a little less painful.

However, these precautions might not be enough considering the enormous potential damage of such an event. Given the nature of solar flares and of our current electricity-entwined world, it may be tough to ever create a foolproof system that stops solar flares in their tracks.

In the case of this villain, there may be no one hero  — we may need the collaboration of a whole league of scientific superheroes around the world.

Edited by Lauren Fuge and Ivy Shih.