The term "X-class" typically refers to a classification of solar flares, which are intense bursts of radiation from the sun. These flares are categorized based on their brightness and energy output, with X-class flares being the most powerful. They can have significant effects on Earth's atmosphere, potentially disrupting communication systems and power grids. In addition to solar flares, "X-class" can also refer to various classifications in other fields, such as X-class asteroids, which are a type of space rock with specific characteristics. Understanding these classifications helps scientists study and predict the behavior of these celestial phenomena.