X1.9 solar flare erupts from Sun, causing brief radio blackout

Updated on 01 Dec 2025 | Category: Science

An X1.9 solar flare erupted from the Sun on 1 December. The associated coronal mass ejection will not strike the Earth.

An X1.9 solar flare erupted from the Sun on 1 December. The associated coronal mass ejection will not strike the Earth.
New Delhi: An X1.9 solar flare erupted from the Eastern Limb of the Sun at 02:27 hours UTC on 1 December. The cluster of sunspots had just rotated into view before shooting off the X-class flare, the strongest category of solar flares, and was subsequently numbered as Active Region 4299 by the Space Weather Prediction Centre, operated by the US National Oceanic and Atmospheric Administration (NOAA). According to the Center of Excellence in Space Sciences India (CESSI) hosted by the Indian Institute of Science Education and Research (IISER) in Kolkata, “Our flare-prediction algorithm indicates a moderate to high probability of X- and M-class flares. Small filaments are present across the solar disk; however, filament-driven Earth-directed CMEs are not currently expected.”
According to the latest forecast discussion by the SWPC, “Solar activity reached high levels due to an X1.9 (R3-Strong) flare observed from new Region 4299 (N22E75, Hsx/alpha). Associated with this event was a Castelli U radio burst, a 988 km/s Type II sweep and a Type IV sweep. The event produced a rapid, partial-halo CME observed off the NE limb, however, initial analysis and model output determined no Earth-directed component.” According to the Solar Influences Data Analysis Centre (SIDC) operated by the Royal Observatory of Belgium, “An associated fast partial halo coronal mass ejection (CME) was detected in the LASCO/C2 coronagraph imagery starting at around 03 UTC with an estimated projected velocity of 850 km/s. The CME is directed off the Sun-Earth line and is not expected to have a notable impact on Earth. There are no solar energetic particles related to the eruptive activities and the proton flux has remained at background levels.”
Space Weather Forecast
While the Coronal Mass Ejection (CME) associated with the X1.9 flare is expected to miss the Earth entirely, geomagnetic disturbances can be caused by the high speed stream from a coronal hole aimed straight at the Earth becoming geoeffective. According to the CESSI forecast, “A coronal hole near the disk center is likely to generate high-speed solar wind streams. The current solar wind speed is above 500 km/s. Overall, space weather conditions remain nominal, with the likelihood of flare- or CME-related disturbances increasing later this week.” According to the latest forecast by the SWPC, “Positive polarity CH HSS influences are expected to wane over 01 Dec, followed by a return to at or near ambient levels over 02 Dec. Another enhancement in solar wind parameters from a negative polarity coronal hole is expected on 03 Dec.”