The story goes back to the time when Goddess Lakshmi was disappointed with Lord Vishnu. She had left his abode and as is obvious, the whole of the Dev Loka was facing a shortage of resources in the absence of the goddess of wealth. While all wanted things to get back to normal soon, the biggest question was how to get the goddess of wealth back as quickly as possible since she brings prosperity and wealth along with her always. That is why Goddess Lakshmi is also known by the Sanskrit name Shri, which translates to prosperity.
Lord Vishnu Approached Lord Brahma
When Lord Vishnu approached Lord Brahma to seek some remedy for it, he got the advise that since Goddess Lakshmi is also known as the daughter of ocean, she has gone into deep meditation amidst the milk of the Kshir Sagar, the great ocean of milk. She would be invoked and requested to come back if the milk of the ocean is churned.The Gods Approached The Demons
Since the churning of the milk of the Kshir Sagar was a big enough task, Lord Brahma mentioned that gods alone will not be able to churn the water of the ocean. They would have to request the demons as well for this. But why would demons help them get prosperity back was the big question. Lord Vishnu, whom we know as the clever deity, had an idea. He knew that alluring the demons was a way to get them to help.
Lord Vishnu knew that there was a vessel filled with nectar inside the Kshir Sagar. He approached the demons and told the demons about the nectar, which if one drinks would become immortal. Now, who does not want immortality? Hence, the gods and the demons agreed to share the nectar and become immortal and therefore, set for the task.When The Nectar Emerged From The Ocean
They went on churning the milk of the Kshir Sagar, and various powerful objects, such as the poison which Shiva drank, the divine conch shell, etc., along with the goddess emerged. Finally, the nectar vessel came in the end. But when it emerged out of the ocean, both the teams wanted their share as soon as possible, as had been decided between them.
But do you think it is a good idea to let the demons drink the nectar and become immortal? Of course not. And we know how clever Lord Vishnu was. He was well aware of the weaknesses of the demons. Hence, he secretly took the form of a beautiful apsara (a nymph) in order to distract the attention of the demons, and appeared before all of them, requesting them to let her poor the divine nectar in the mouth of every god, turn wise.Lord Vishnu Disguised As Apsara Mohini
Fooling the demons, Lord Vishnu disguised as Mohini, the apsara, poured nectar into the mouth of the gods and mere water in the mouth of the demons. Initially, the demons did not realise it, but one of them, known by the name Rahuketu, secretly saw what Mohini had been doing.Rahuketu Revived As Two: Rahu And Ketu
In order to drink nectar, they crept in amongst the gods, so that they could drink the nectar. However, to the disappointment of the gods, Rahuketu did succeed in it, and it was too late when the gods came to know about it. Yet enraged, Lord Vishnu chopped off the head of Rahuketu. But having become immortal already, the head and the torso got separated but he did not die.
The head of Rahuketu is today known as Rahu and the torso is known as Ketu. Rahu and Ketu are today known as the north and south lunar nodes respectively, because they mark the north and south points of the intersection of the sun and the moon.Rahu And Ketu Caused The First Solar Eclipse
Hindu mythology says that Rahu, after his head was chopped off, blocked the path of the Surya Dev, the sun god of Hindus. This caused chaos all around on the earth and Rishi Atri, a divine sage of those times, came to the rescue. He used his divine powers and removed Rahu from the path of the sun, bringing the sunlight back.
This day was marked as the first solar eclipse ever. That is how Rahu and Ketu, the planets considered retrograde, became immortal. This is often narrated as the birth story of Rahu and Ketu, born on a solar eclipse day.