Two massive solar flares emanating from the sunspot AR 3429 and producing a surge of plasma over the Sun’s northeastern limb struck Earth as recently as at 7 AM on Monday (September 11, 2023). According to data from NASA’s Solar and Heliospheric Observatory (SoHO), an M1.39-class solar flare erupted on the side of the Sun that faces Earth, sparking a shortwave radio blackout over the Pacific Ocean following solar radiation from the flare. Hours later, at 9.30 AM, another solar flare of M1.19-class in intensity sparked a blackout over South Korea, Japan and the eastern regions of China. Complicating the situation, another sunspot region, AR3423, which doubled in size since Friday and spanned 100,000 kilometres in width, posed a further threat.
Blackout Over Oz & Indian Ocean
On Thursday, April 6 this year, a solar flare caused a not-too-significant shortwave radio blackout over the Indian Ocean, a report said. According to the Space Weather website, an ‘M class’ solar flare caused the blackout. It warned that the sunspot might emit more flares in the coming times.
Blackout over the US & Pacific Ocean
Subsequently, a giant sunspot—a huge dark patch known as AR3354—exploded on Sunday, July 2, 2023, creating a powerful solar flare that tore through Earth’s atmosphere and resulted in a radio blackout lasting around 30 minutes over several parts of the US and the Pacific Ocean, reported Space.com. The sunspot is seven times the width of Earth. NASA’s Solar Dynamic Observatory (SDO) observed the flare, bursting out of the Sun at 15:14 EDT, as a bright, ultraviolet flash and classified it as an X1.0 flare, the strongest type of solar flare in existence. Within 48 hours, it had expanded to a size roughly equivalent to 3.5 billion sq km, or ten times the size of Earth.
June 2023 witnessed the highest monthly average for sunspots in 21 years. Scientists monitoring space weather were alarmed by the rapid appearance of the giant sunspot for fear that it would trigger a series of possibly catastrophic solar storms.
NASA’s Solar Dynamics Observatory
NASA’s Solar Dynamics Observatory (SDO) is a satellite put into geosynchronous orbit and built to study the Sun’s influence on Earth by scrutinizing the solar atmosphere. The SDO aims to understand the dynamic solar activity that dictates weather conditions in near-Earth space. SDO helps us study where the Sun derives its energy from, how the interior of the Sun behaves and how the Sun’s atmosphere stores and releases energy in dramatic eruptions.
Every 12 seconds, the SDO records the Sun’s images in 10 ultraviolet light wavelengths, each revealing different solar features and assigning a distinctive colour. Each image is eight times the resolution of HD video. The SDO studies the Sun’s blazing atmosphere—right from recording dark coronal holes or bright active regions on the Sun’s surface to intense flares and eruptions that lash out millions of miles above the surface.
Aditya L-1’s Sojourn to The Sun
A major scientific goal of ISRO’s Aditya L-1 Sun mission is to uncover the extent of the Sun’s influence on Earth’s climate, particularly and space weather dynamics, in general, by studying solar phenomena up close in real-time. This understanding will lead to more precise forecasts of space weather and offer important lessons in reducing their potentially harmful effects on space missions and technologies on Earth.
Activities on the Sun can result in space weather events that pose risks to astronauts and affect the ionosphere surrounding Earth. The ionosphere layer in Earth’s upper atmosphere contains ions and free electrons. This layer is critical in influencing global communication and navigation systems besides reflecting radio signals. The major objectives of the Aditya L-1 mission include the study of the physics of solar corona and its heating mechanism, temperature anisotropy and origin of coronal mass ejections (CMEs) and flares, besides near-earth space weather.
There are several categories of solar flares: B, C, M and X.’ B class’ solar flares are minor ones, while ‘X class’ is the most potent. Medium-sized ‘M class’ flares typically cause brief radio blackouts affecting Earth’s polar regions. Sometimes, small radiation storms ride on the back of an ‘M class’ flare. ‘C class’ flares are insignificant and have little effect on Earth. ‘X class’ flares are huge, significant events that may lead to radio blackouts worldwide and radiation storms in the upper atmosphere. An ‘X class’ flare is ten times the strength of an ‘M class’ flare and 1,000 times more powerful than a ‘B class’ flare.
What Are Solar Eruptions & Flares?
When the Sun’s magnetic fields suddenly release the energy stored in them, huge explosions, called ‘solar flares’ can happen. These flares produce sudden, intense light flashes, sending high-energy particles, and sometimes, these explosions can create very strong X-rays and bursts of ultraviolet (UV) rays. These particles can reach Earth in a few hours or days, creating magnetic storms in Earth’s atmosphere that can last for days.
Solar flares can heat a substance to several millions of degrees in just minutes, producing a burst of radiation that spans the electromagnetic spectrum, from radio waves to X-rays and gamma rays. Long-lasting flares such as the one emanating from sunspot AR3354 are sometimes accompanied by coronal mass ejections (CMEs)—events where magnetic fields lash out a huge amount of stellar material in the form of plasma that is ejected by the Sun.
Effects of Solar Flares:
- Radiation storms in the upper atmosphere
- Radio blackouts across the world
- Transformer explosions
- Widespread mobile phone outages
- Fluctuations in magnetic fields reaching Earth’s surface
These eruptions and flares can be dangerous for space missions, astronauts, and satellites. X-rays are very energetic light that we cannot see with our naked eyes but can penetrate the skin and muscles. Ultraviolet light is a kind of light that is even higher in energy than the light we see. It is what can cause sunburn if a person is out in the Sun for too long. The Aditya-L1 mission wants to understand these Sun explosions better. By doing that, they can better predict when and how they could affect space phenomena.