Watch Out For Aurorae Tonight – The Strongest Solar Flare Of 2025 So Far Just Erupted From The Sun

The Sun has just fired off its most powerful solar flare of 2025, causing radio blackouts across half the globe. As the barrage of charged particles makes its way toward Earth, the aurorae borealis – or Northern Lights – could become visible at unusually low latitudes tonight.

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Solar flares are bursts of electromagnetic radiation that arise from tangles in the Sun’s magnetic field, and travel through space at the speed of light. The strongest of these are categorized as X-flares, three of which have now been recorded in the past few days.

The first two were detected on November 9 and 10, and ranked as X1.7 and X1.2, respectively. Both of these flares arose from an active sunspot called AR4274, and were accompanied by coronal mass ejections (CMEs). 

CMEs are expulsions of magnetized plasma that travel much slower than flares. When these charged particles collide with the Earth’s magnetic field, they are funneled towards the poles, triggering geomagnetic storms as they interact with oxygen and nitrogen molecules in the atmosphere and light up the night sky in a dazzling array of color.

The two CMEs from earlier this week are thought to have combined with – or “cannibalized” – each other, producing aurorae at low latitudes across the Northern Hemisphere. However, according to the NOAA's Space Weather Prediction Center, a third flare erupted on Tuesday morning, this time clocking in at a considerably more powerful X5.1.

An accompanying CME is forecast to reach Earth on Wednesday night, triggering a severe G4 geomagnetic storm (G5 is the strongest possible classification). NOAA says that this could result in aurorae becoming visible as far south as Alabama and northern California.

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Tuesday’s flare was the strongest since October 2024, and triggered strong, R3-level radio blackouts (on a scale of R1-5) across Europe and Africa – which happened to be facing the Sun at the time of the eruption. These disturbances occur when flares blast the Earth’s ionosphere, which carries radio signals sent and received by long-distance communications systems. Depending on the extent to which a flare ionizes the ionosphere, radio signals may become distorted or lost, resulting in what’s known as a blackout.

Prior to this week, the strongest solar flare of the year was an X2.7 eruption that occurred back in May. According to NOAA, strong geomagnetic storms could continue into November 14, although that forecast will be updated as more data is collected.