These phenomena vary in an 11 year cycle called the solar cycle. They include sunspots, flares, prominences and the solar wind. Sunspots are dark markings on the Sun's photosphere. They appear dark because they are cooler than the surrounding area. The number of sunspots reaches a maximum and a minimum over an 11 year cycle called the sunspot cycle.
Sunspots generally occur in pairs and are regions of strong magnetic fields.
Solar flares are explosive eruptions of gas that occur at the site of a sunspot. They can extend beyond the corona. Flares are short-lived solar activity that last several minutes and they are much hotter than the Sun's surface. A solar flare may cause aurora on Earth, interfere with radio transmissions and even cause power outages. Prominences are huge eruptions of gas that are ejected up to thousands or even hundreds of thousands of kilometers above the Sun's surface and fall back as arches.