Cosmox Blogs

Dec 12, 2024

Solar Flares: Earth's Hidden Threat from the Sun

Imagine being stuck in your house during hurricanes and thunderstorms. An eruption of X-rays and ultraviolet light from the sun causes radio blackouts, which ultimately results in the loss of communication between various disaster management teams trying to rescue the people. Space weather and Earth weather combine to create havoc in people's lives.

This was a true incident that occurred after a Solar Flare eruption in September 2017. This is why studying and monitoring space weather activities becomes an important part of our everyday lives. 

Solar flares are huge explosions of electromagnetic radiation from the Sun.  Flares are our solar system’s largest explosive events. They are seen as bright areas in the sun and they can last from minutes to hours. We typically see a solar flare by the photons (or light) it releases, at almost every spectrum wavelength. These flares are often associated with solar magnetic storms known as coronal mass ejections (CMEs).  CMEs’ are huge eruptions of magnetic plasma clouds from the Sun's corona.

Origin & Classification

The sun is a dynamic star, made of super-hot ionized plasma gas. The complicated structure of the sun's magnetic field causes loops-like structures of lines coming out of the sun’s surface. These lines control where plasma can go causing plasma loops.

The plasma may cool and pour down as Plasma rain. The loops are like wires carrying electricity. If they get too close to each other they can release tremendous energy in the form of solar flares and Coronal Mass ejections. 

Solar Flares are classified depending on the energy carried by them.

A & B-class solar flares

The A & B-class are the lowest class of solar flares. They are very common. The background flux (amount of radiation emitted when there are no flares) is often in the B-range during solar maximum and in the A-range during solar minimum.

C-class solar flares

C-class solar flares are minor solar flares that have little to no effect on Earth. Only C-class solar flares which are long in duration might produce a coronal mass ejection but they are usually slow, weak, and rarely cause a significant geomagnetic disturbance here on Earth.

M-class solar flares

M-class solar flares are what we call medium-large solar flares. They cause small (R1) to moderate (R2) radio blackouts on the daylight side of the Earth. Some eruptive M-class solar flares can also cause solar radiation storms. Strong, long duration M-class solar flares are likely candidates to launch a coronal mass ejection. If the solar flare takes place near the center of the Earth-facing solar disk and launches a coronal mass ejection towards our planet, there is a high probability that the resulting geomagnetic storm is going to be strong enough for aurora on the middle latitudes.

X-class solar flares

X-class solar flares are the biggest and strongest of them all. On average, solar flares of this magnitude occur about 10 times a year. Strong to extreme (R3 to R5) radio blackouts occur on the daylight side of the Earth during the solar flare. If the solar flare is eruptive and takes place near the center of the Earth-facing solar disk, it could cause a strong and long-lasting solar radiation storm and release a significant coronal mass ejection that can cause severe (G4) to extreme (G5) geomagnetic storming at Earth.

Effects of Solar Flares & CMEs

Geomagnetic storms - A geomagnetic storm is a major disturbance of Earth's magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth. The largest storms that result from these conditions are associated with solar coronal mass ejections (CMEs). These Storms result in intense currents in the magnetosphere, changes in the radiation belts, and changes in the ionosphere, including heating the ionosphere and upper atmosphere region called the thermosphere.

Harmful radiation effects- If Solar Flares or CMEs are directed at Earth, such flares and associated CMEs can create long-lasting radiation storms that can harm satellites, communications systems, and even ground-based technologies and power grids.

Formation of Auroras- The Formation of Auroras has attracted tourists as well as scientists for centuries in the northern and southern poles. It might be quite surprising to know that Auroras form due to CMEs and solar flare-related activities. When the particles of CME seep through Earth's magnetosphere, they cause substorms. Most of these particles get deflected away but some of them slam into our thin, high atmosphere, accelerate towards the poles due to the structure of our magnetic field, and collide with Earth's oxygen and nitrogen particles. As these air particles shed the energy they picked up from the collision, each atom starts to glow in a different color. The aurora's characteristic wavy patterns and 'curtains' of light are caused by the lines of force in the Earth’s magnetic field.

The green we see in the aurora is characteristic of oxygen, while hints of purple, blue, or pink are caused by nitrogen. Sometimes, when the aurora is energetic we see scarlet red colour due to the interaction of high-altitude oxygen with solar particles.

The Carrington Event (1859)

The solar cycle is the Sun's activity cycle, which is a continuous pattern of the Sun's activity level that lasts about 11 years. Solar maximum is a period of increased solar activity that occurs roughly every 11 years during the Sun's solar cycle. Even though solar flares and ejection-related activities occur on a daily basis. The intensity and frequency increase as the sun approaches the solar maximum.

A large number of sunspots appear during the solar maximum period which gives rise to a number of space weather-related activities including super flares ( intensified solar flares ) and massive CMEs. The Carrington Event was a large solar storm that took place at the beginning of September 1859, just a few months before the solar maximum of 1860.

On the first day of September 1859, Richard Carrington was observing sunspots when he saw a bright flash of light which is now believed to be a CME. The effects of the September 2, 1859, solar storm were unprecedented. People saw auroras as far south as the Caribbean and Mexico. At some more northerly latitudes, it’s said the sky was so bright with auroras that birds, thinking it was morning, began to sing. But it wasn’t all awe and beauty. There were widespread stories of people receiving shocks from door knobs and other metal objects due to the induction of electrical currents. Around the world, compasses at sea failed to work, causing some ships to become lost.

The Carrington Event, in the end, caused minimal damage in an age when there was little that could be damaged. But were it to occur today, it would be catastrophic.

The Upcoming Solar Maximum of 2025

In 1859 there was hardly anything that could be damaged except a few radio and telegraph communication systems. But today computers manage our society. They affect every single aspect of our lives, from traffic control to power grids to banking to healthcare to entertainment. The birth of the integrated circuit gave us the modern world, appearing in all modern devices from toasters to televisions and cell phones to cars. What would happen if an event like the Carrington were to happen today?

There would almost certainly be widespread burnout of electronic circuits and the failure of power grids on a much bigger scale. The recovery could take months to years depending on how developed the country is. The effects would be drastic for healthcare and other basic day-to-day needs providing fields. In space, satellites would also fail as their electronics fried. This has happened several times during geomagnetic storms on a scale far smaller than the Carrington Event. The most recent was in March 2022, when 40 Spacex Starlink satellites failed after a CME.

The current solar cycle began in 2019 and scientists predict it will peak sometime in  2024 or 2025 before the Sun returns to a lower level of activity in the early 2030s. During this period, up to 115 sunspots, which are often sites of solar flares and coronal mass ejections, are anticipated. Although solar wind takes days to reach Earth, providing some warning, extremely powerful storms like the Carrington Event could reduce this lead time to hours.

During this period the primary concern for many space as well as world government organizations is to minimize the damage as much as possible. There are several ways to prevent the damage but the question is are these methods enough?

Are we prepared?

Studies have placed the potential global financial cost of a modern-day Carrington Event would be around trillions of dollars. The first-world countries might recover in a few years but the underdeveloped ones might take years to go back to normal. This is why preparedness for this space disaster should be taken seriously.

Monitoring and prediction

While coronal mass ejections can travel thousands of kilometers per second, they typically take several days to reach the Earth. Ideally, we would have a constellation of satellites at several points between the sun and Earth's orbit working with a network of ground-based sensors to constantly monitor solar activity. This would give additional time to prepare.

However, with existing capabilities, it's not likely there would be enough time to adequately prepare for a coming storm, once identified. Not only is the correct infrastructure not in place but there needs to be a better fundamental understanding of the solar and geospace sciences in order to create more accurate models to predict an incoming disaster.

However, there are joint efforts by many space and atmospheric sciences organizations along with private companies to develop more accurate forecasting of events on the sun and in near-Earth space that is critical for national security and society’s well-being.

Protection of energy grids and power transformers

From lighting of our houses to pumping water from the ground, we are dependent on power grids for everything. The worst effect of the solar storm is definitely causing permanent damage to them. Solar storms can cause currents to flow through the power grid, which can damage components like transformers, relays, and circuit breakers.

Shutting down the power grids for some time, and using temporary transformers using shield equipment are some potential measures to protect against the damage but they too come with a cost.

Personal Safety measures

Taking personal precautions is also an important part of preparing. 

-> Follow the guidelines from news and local management bodies and stay updated.

-> Unplug every piece of electronics that is attached to the switchboard.

-> Get all necessities required for a few days to weeks in a power outage.

-> Use shielded Faraday bags to protect your devices like laptops and mobile phones.

Conclusion

Out of all aspects of preparedness the most challenging yet the most important ones are spreading awareness about this topic and continuously monitoring the solar activities accurately. Advancements in space technologies bring us great hope when events like this occur. Apart from the drastic effects, solar flares and CMEs provide us a medium to understand not only the Sun but also our solar system in a better way. They serve as proof to the saying that the mysteries of the universe are endless.