X — X-class Solar Flares

X - X-class Solar Flares. Solar flares are giant explosions on the sun. The biggest and strongest flares are known as X-class flares. Some x-class flares are by far the largest explosions in the solar system. Loops tens of times the size of Earth leap up off the sun's surface when the sun's magnetic fields cross over each other and reconnect. In the biggest events, this reconnection process can produce as much energy as a billion hydrogen bombs. Source: NASA