Vasuki helped in this mission. He was used as the rope tied around the spiritual mountain Mandara, which was the rod, used to churn the ocean. When the Amrita was found the gods wanted to keep it for themselves as they felt that the demons would use it for the wrong purpose. Vasuki being a demon, his instincts were for personal glorification and materialistic happiness rather than universal good. He drank the nectar of immortality secretly. The Sun and the Moon complained to Lord Vishnu, the creator of the Universe, who was very angry at this deception. In anger he threw the Sudharshan Chakra (disk weapon) at Vasuki and cut him into two. Vasuki had drunk the Amrita and was immortal, therefore could not be killed. He remained in the skies as Rahu (the head) and Ketu (the lower half), a permanent reminder to the other planets (gods) of the darker side of life that we have to defeat in the pursuit of immortality.
Usually the moon’s path passes above or below the sun’s path and no eclipse occurs. But, periodically the moon overtakes the sun at the place where their paths intersect. This causes the sun or the moon to be hidden from the earth’s view and is the phenomenon called solar or lunar eclipse. These points of intersection are the north and south lunar nodes, or as they are referred to in Hindu mythology, Rahu and Ketu. Therefore, in the symbolic language of mythology, Rahu and Ketu are said to ‘swallow up’ Sun and Moon. In Sanskrit this is known as Grahan or seizing. However, Ketu is really not a planet. Sun and Moon make in a given day one round of the Earth and Ketu is one of those points when they are in exact alignment with Rahu being the other point. These points are called ‘nodes’ and the path is called the elliptic. Vedic astrologers ascribe special power to these points and in many cases their effects are stronger than the traditional planets. Ketu is the descending node of the moon through the eyes of Indian astrology. Ketu is known to afflict the Sun more so than any other planet. This is in contrast to Rahu, which is associated with the Moon.
Ketu, like Rahu is also a shadowy planet, catches snakes, and is sanyasin by profession. She lives on alms, belongs to a mixed caste, and knows mantras. She is medical practitioner, grateful but clever, and dexterous, makes pilgrimages, practices yoga, has divine and supernatural strength, and helps in salvation of man from the cycle of birth and rebirth. Ketu has a variegated color. Ketu resides in mountains and forests. Ketu lives in corners of houses .Ketu‘s nature is Satvik. Ketu, the dragon’s tail is an eunuch Karmic planet. It is a planet of secrets and mysteries. The position of Ketu in a native chart shows the qualities and characteristics developed during past lives. A planet in conjunction with Rahu has a special significance in relation to the results signified by Ketu’s association with the other planet. Ketu’s placement in the first half of the natal chart is considered to be highly auspicious for one’s steady rise. While the person’s childhood may be difficult, he will make progress as the years advance and will become more prosperous with age. The case would be reverse if Ketu is placed in the second half of the native’s chart. A well-positioned Ketu with good associations and aspects facilitates the native to rise to great heights and bestows name, fame and social esteem. Afflicted nodes (Ketu and Rahu) often cause setbacks and difficulties, tensions and turmoil. But mostly after undergoing some trying phases in life, the natives have chances of subsequent improvements including interest in spiritual aspects of life, as also in parapsychology and the occult. Ketu has the influence of Mars conducting Saturn. Ketu is exalted in Sagittarius, ruler in Pisces, harmonious in Aries, debilitated in Gemini, detrimental in Virgo and harmonious in Libra.
Ketu rules 7 years in the planetary life cycle. Ketu always has a sting in its tale. So the at the end of Ketu Maha Dasha one has to be vary of unexpected happenings. Ketu is considered the keeper of the book of our life- past and present Karmas .Ketu has an unusual association in terms of direction. He is most often noted to be the ‘center’ that has really no direction at all. Ketu is associated with the metal Lead. Earth is considered the element of Ketu.
Dogs are ruled by it. Its stone is ‘Cat’s Eye’ or Lehsunia. Its conjunction with sun and moon is considered malefic in Hindu astrology but good in Western astrology. Ketu has a tendency to behave like Mars and as a result fire and accidents are also associated with Ketu.

Ketu is headless half planet, malefic though not as malefic as Rahu. It is considered as Moksha Karak (liberating factor from birth and death cycle).It bestows spiritual tendencies, ascetics, and non attachment to worldly desires and ambitions. It is associated with smoky- grey color and rules the number 7 in astrology.