A powerful solar flare hit Earth causing radio blackouts

More can be expected in the days to come.
Ameya Paleja
Solar flare.jpg

A powerful solar flare hit Earth last week, causing a radio blackout over parts of Australia and the South Pacific last week, CNET reported. This is one of the most powerful flares seen since October last year and might be a sign of what is coming next.

A solar flare is an eruption of electromagnetic radiation from the Sun's surface. According to the European Space Agency, flares occur when energy stored in magnetic fields on the solar surface is suddenly released.

Sometimes, areas on the Sun develop intense magnetic fields where the convection process stops, dropping the temperatures and making them appear darker. These are sunspots and serve as an indicator of activity on the solar surface. The number of sunspots increase as the Sun goes through its 11-year cycle, where it flips its magnetic poles.

Sunspot AR3182

Solar scientists carefully look at sunspots developing on the surface of the Sun in a bid to predict when solar flares might occur. The recent flare came from a complex sunspot that has been cataloged as Sunspot AR3182.

Last week, this sunspot gave off a powerful solar flare, classified as X1.2 class. The X-class solar flares are the most powerful bursts of radiation known to humanity. Class M-flares have moderate intensity, while classes A, B, and C are used for low-intensity flares.

The 1.2 in the classification denotes that the flare was a low intensity among the X-class flares. So far, sunspot AR3182 has been facing away from the Earth and blasting off flares on the far side of the Sun. However, with the sunspot now facing the Earth, the wrath of the sunspot is aimed directly at us.

Coronal Mass Ejections

Even an X-class solar flare could be preferred over a coronal mass ejection (CME), which is the expulsion of plasma alongside magnetic radiation from the Sun's corona. Earlier, CMEs were thought to follow solar flares. However, these two events are now known to occur independently. A CME loaded with plasma and magnetic energy interacts with the Earth's magnetic field and atmosphere to cause a geomagnetic storm.

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Classified in categories G1 to G5, geomagnetic storms also occur at different intensities, depending on the intensity of the CME that interacts with the Earth's magnetosphere. Weaker geomagnetic storms cause auroras that can be seen beyond the usual areas of the poles.

However, stronger geomagnetic storms can cause communications to blackout, as they did recently, but for extended periods while also damaging electrical equipment, which can lead to power outages.

The Earth has faced powerful geomagnetic storms earlier, with the most severe one recorded in 1859. However, back then, humanity was not as dependent on technology for communication, navigation, and energy supply as we are today. An incident on a similar scale could have devastating results for the modern economy, and scientists are therefore keen to be able to predict the occurrence of such an incident accurately.

With the Sun approaching the peak of its solar cycle in the next few years, more X-class solar flares are expected, and so are powerful CMEs.