Sun in hydrogen alpha light

This photo shows an enormous solar flare over 230,000 miles long. This event lasted about 30 minutes. Solar flares are immensely hot (~30 million degrees) eruptions on the Sun which emit charged particles of plasma. When these particles traveling at 1,000,000 mph are intercepted by the Earth's magnetosphere, they become excited and glow. We can see them as the Aurora Borealis. The thin dark lines covering the Sun's surface are called filaments and are caused by the Sun's magnetism.