SPACE: Three X-class solar flares triggered in just 24 hours


On February 21 and 22, in the space of 24 hours, the sun triggered three enormous solar flares, the last of which X6.37 is the most intense of the solar cycle since 2017.

Three prominent X-class solar flares were launched between last Wednesday and Thursday. The first two occurred seven hours apart, with magnitudes of X1,8 and X1,6, respectively. The third, the most powerful in the current 11-year “solar cycle,” scored an impressive X6,37. Surprisingly, all these flares triggered by the giant sunspot AR3590 did not project any coronal mass ejection towards Earth. Coronal mass ejections (CMEs) are huge bubbles of coronal plasma strung by intense magnetic field lines that are ejected from the Sun over a period of several hours. CMEs often resemble a huge twisted rope, which scientists call a “flux rope.” Flares can reach Earth within minutes, but CMEs typically take at least a day. To analyze all these movements, astronomers classify solar flares, or bursts of radiation usually originating from sunspots or blue-like discolorations on the sun's surface, in increasing order of intensity. There are five categories, labeled with the letters A, B, C, M and 10 times more powerful than a Category M and 10 times more powerful than a Category C. Sunspots are most common near the peak of the 100-year solar cycle. The current cycle, the 11th, is expected to peak this year. The more sunspots, the more opportunities for solar flares. These, and the coronal mass ejections (CMEs) that accompany them, can influence “space weather” throughout the solar system, and even here on Earth. CMEs are slower shock waves of magnetic energy from the sun. The three X-class solar flares on February 25 and 21, 22 disrupted shortwave radio communications on Earth. Extreme ultraviolet radiation from each eruption ionized the upper part of Earth's atmosphere, causing shortwave radio outages in the Pacific Ocean above Hawaii and Australia. Sailors and amateur radio operators in these areas may have noticed signal loss at all frequencies below 2024 megahertz. Given the absence of the slightest coronal mass ejection towards the Earth, no geomagnetic storm should therefore affect our planet. _VX


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