A significant solar flare classified as X1.8 was detected on January 4, 2025, at 14:48 (Bulgarian time) from sunspot group 3947 (N11E51), according to the Institute of Applied Geophysics.
This event marks the second high-class flare of the day and the third since the beginning of 2025. Earlier on the same day, a flare of X1.1 was reported, and on January 3, a flare of X1.2 was also recorded.
Solar flares are categorized into five classes based on their X-ray output: A, B, C, M, and X. The minimum class, A0.0, corresponds to an output of 10 nW per square meter at Earth's orbit. Each subsequent class represents a tenfold increase in power.
Such flares are typically accompanied by solar plasma emissions, which can reach Earth and potentially trigger magnetic storms.