The phenomenon that occurs when the moon blocks the sun is called a solar eclipse. This celestial event takes place when the moon passes directly between the Earth and the sun, casting a shadow on the Earth's surface. Solar eclipses can be total, partial, or annular, depending on the alignment of the moon, Earth, and sun. During a total solar eclipse, the moon completely covers the sun, revealing the solar corona and creating a dramatic effect in the sky. These events are relatively rare, with total solar eclipses visible from specific regions on Earth, often leading to gatherings of people hoping to witness the spectacle.