What are the beliefs related to lunar and solar eclipses?

Question

What are the beliefs related to Lunar and Solar eclipses according to Hindu culture? I have heard that they are the result of trouble making by Rahu and Ketu by devouring the sun/moon for a while.

Answer 1

You heard correctly. The story of Rahu and Ketu occurs after the churning of the ocean, when Vishnu turned into the beautiful woman Mohini in order to trick the Asuras (demons) and give the Amrita, the nectar of immortality, only to the gods (gods). The Adi Parva of the Mahabharata describes what transpired next:

And all the gods at that time of great fright drank the Amrita with delight, receiving it from Vishnu. And while the gods were partaking of it, after which they had so much hankered, a Danava named Rahu was also drinking it among them in the guise of a god. And when the Amrita had reached Rahu's throat only, Surya and Soma (recognised him and) intimated the fact to the gods. And Narayana instantly cut off with his discus the well-adorned head of the Danava who was drinking the Amrita without permission. And the huge head of the Danava, cut off by the discus and resembling a mountain peak, then rose up to the sky and began to utter dreadful cries. And the Danava's headless trunk, falling upon the ground and rolling thereon, made the Earth tremble with her mountains, forests and islands. And from that time there is a long-standing quarrel between Rahu's head and Surya and Soma. And to this day it swalloweth Surya and Soma (during solar and lunar eclipses).

I should note that although in this account (and the similar account in the Srimad Bhagavatam) only the head survives and the headless body dies, in more popular versions of the story both the head and the body survive separately due to the Amrita being in the middle of the Asura's throat - the head is known as Rahu and the headless body is known as Ketu. And this isn't information entirely absent from scripture; the Karna Parva of the Mahabharata says "the headless planet Ketu (is peerless) among all the planets".

Also, it should be noted that the Rahu and Ketu have some basis in astronomy: they correspond to the two lunar nodes, and eclipses occur whenever the sun or the moon passes through one of these nodes.