A solar eclipse is a sweet cosmic gift—a combination of orbital mechanics, random chance, and dazzling celestial aesthetics. They are also more common than most people would think; if you manage to live through the entire 21st century, you’ll be around for 224 solar eclipses. But only seven of those—or 3.1%—will be of the particularly rare variety known as a hybrid eclipse, one of which is occurring April 20.