Solar flares are sudden bursts of magnetic energy from the Sun, produced when stressed magnetic fields snap and reconnect. They release intense light and radiation, sometimes strong enough to affect spacecraft and radio signals. We typically observe flares by monitoring X-rays on the GOES spacecraft. You can learn more about how they work in The Library.

Flares are classified by their X-ray brightness: B (small), C (moderate), M (strong), and X (the rare, powerful ones). Each class is ten times stronger than the last, and the number that follows, like M2.5 or X1.0, shows its strength within that class.

Try the flare simulator below to see how different flare strengths and shapes appear in X-ray light curves. Adjust the settings and build your own solar flare.