Most Powerful Geomagnetic Storm in Years Led to Auroras Lighting the Sky Across the Globe

Earth has been hit by the strongest geomagnetic storm in over six years, caused by an eruption from an exceedingly rare "double" X-class flare. This event illuminated global skies with vibrant auroras, signaling the likely peak of the sun's 11-year cycle of activity, known as solar maximum. Consequently, Earth may face more such potentially harmful solar storms in the upcoming months.

Dual X-Class Solar Flare and Its Impact on Earth's Magnetosphere

On March 23, the Sun discharged a formidable 1.1 magnitude X-class solar flare, the most robust type of solar explosion. This event was noteworthy due to its composition of two simultaneous eruptions, termed a sympathetic solar flare, stemming from distant sunspots AR3614 and AR3615.

These dual explosions propelled a substantial mass of plasma and radiation, referred to as a coronal mass ejection (CME), toward Earth's magnetosphere on March 24. This collision weakened the planet's natural shield, enabling solar radiation to penetrate deeper into the atmosphere, prompting auroras in Australia and New Zealand, as well as the aurora-like phenomenon STEVE in Alaska.

The severity of the resulting geomagnetic storm peaked at a classification of severe (G4), marking a significant event not witnessed since September 2017. CMEs, colossal clouds of solar plasma, are typically ejected during periods of heightened solar activity, often accompanying magnetic realignments at sunspots. This specific CME coincided with an X1-class solar flare on March 22.

Brett Carter, an associate professor in space science at RMIT University, elucidated the distinction between solar flares and CMEs, underlining their separate natures despite their occasional simultaneous occurrences.

Geomagnetic storms, precipitated by CMEs interacting with the Earth's ionosphere, are graded on a scale from G1 (minor) to G5 (extreme), with G4 storms being relatively uncommon, occurring approximately 100 times per 11-year solar cycle. The exceptional intensity of this solar event and ensuing geomagnetic storm serves as a poignant indication of the sun's approach to solar maximum.

Solar maximum denotes the peak phase of the sun's approximately 11-year activity cycle, during which heightened solar activity, including increased occurrences of solar flares and CMEs, is anticipated. Consequently, the recent solar explosion and resulting geomagnetic disturbance portend the likelihood of more intense solar phenomena in the foreseeable future as the sun approaches this critical phase of its cycle.

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Geomagnetic Storm Creates Spectacle of Auroras Across the Globe

As solar storms assail Earth, radiation trapped by magnetic poles amplifies this natural phenomenon. The severe G4 geomagnetic storm sparked vivid auroras over New Zealand. Moreover, the Met Office suggests auroras could also be seen in the UK, particularly in Wales and Southern England, with Scotland and Northern Ireland likely observing displays overnight.

In the US, the northern lights may be visible as far south as Alabama or northern California in the U.S. Although the CME occurred during daylight hours in the U.S. and Europe, obscuring auroras, New Zealand experienced a dazzling spectacle of the aurora australis or southern lights.

Typically confined to regions near the Earth's magnetic poles, auroras extend to lower latitudes during coronal mass ejections when the Sun releases a heightened volume of charged particles.

Today, the National Oceanic and Atmospheric Administration of the U.S. announced a significant geomagnetic storm. Rated as G2, the storm is deemed moderate and has the potential to disrupt radio communications and power systems at high latitudes. Despite not posing severe disruptions to communication systems, this storm is expected to enhance the visibility of the Northern Lights over a broader geographical area.

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