What is Surya Grahan and why is it significant in Hinduism?

Surya Grahan (solar eclipse) is one of the most significant celestial events in Hindu tradition. Mythologically, it represents the demon Rahu swallowing the Sun, rooted in the Puranic story of the Samudra Manthan. Spiritually, it is a time of exponentially amplified spiritual energy when mantra japa, sacred bathing, and charitable giving yield merit a hundred thousand times greater than at ordinary times.