Space Weather 101
☀️ Solar Flares
View live Solar Flares data →What is Solar Flares?
A solar flare is a sudden, intense burst of radiation released when magnetic energy that has built up in the Sun's atmosphere is abruptly released, usually near sunspot groups where magnetic field lines have become twisted and tangled. Flares release energy across the entire electromagnetic spectrum, from radio waves to X-rays and gamma rays, all essentially simultaneously.
Why it matters
Flares are classified on a standardized letter scale (A, B, C, M, X) based on their peak X-ray brightness, with each letter representing a tenfold jump in intensity. This scale is the backbone of solar activity reporting and directly drives real-world radio blackout warnings.
Typical values
C-class flares are common and mostly go unnoticed on Earth. M-class flares can cause brief radio blackouts, mainly near the poles. X-class flares are the rare, major events — the largest ever recorded (2003) was estimated around X28, over a thousand times more intense than a typical M1 flare.
How scientists measure it
GOES weather satellites carry dedicated X-ray sensors that continuously monitor the Sun's X-ray output. A flare shows up as a sharp spike in this measurement, and its peak value determines its letter-and-number classification.
Why it affects Earth
Because flares release energy as light, their effects reach Earth in about 8 minutes — the time it takes light to travel from the Sun. The burst of X-rays and extreme ultraviolet light ionizes Earth's upper atmosphere on the sunlit side, which can absorb or disrupt high-frequency radio signals, causing sudden radio blackouts.
FAQ
Do all solar flares cause aurora?
Not directly — flares themselves mainly affect radio communication. Aurora is driven more by the solar wind and any associated coronal mass ejection, which often (but not always) accompanies a large flare.
How is flare class calculated?
Each letter (A, B, C, M, X) represents a tenfold increase in X-ray flux. The number after the letter is a linear multiplier within that class — an X2.5 flare is 2.5 times the intensity of X1.0.