An "X-class" solar flare erupts from the limb of the Sun in this 2014 image. X flares are the most powerful solar flares, which are giant eruptions of radiation and charged particles. Such flares can disrupt spacecraft, knock out power grids on Earth's surface, and cause other problems. Such flares are most common near the peak of the Sun's 11-year magnetic cycle. The next cycle currently is forecast to peak in 2024. [NASA/GSFC/SDO/Wiessinger]