In Vedic astrology Rahu and Ketu are considered as two planets. Both of them have a great impact in the mental and physical state of a person , so they are considered as existing planets despite of their astronomical absence in the solar system.
In Vedic astrology Rahu and Ketu are celestial planets with no mass and shape . They are celestial points based on mathematical calculations
Rahu and Ketu in Astronomy
Since these planets do not exist physically , they have no astronomical significance. They are actually ecliptical points, where the line of sight of moon concides with the line of sight of sun , and eclipse happen.
This position of sun and moon is also linked to a story mentioned in Puranas.
Origin of Rahu and Ketu
During Samudra Manthan both Devtas and Asuras were arranged in a queue waiting for their chance to consume the nectar from the churning of the ocean of milk (Kshirsagar).
Meanwhile, to distract the demons, Lord Vishnu took the form of a beautiful lady called Mohini. The demons were captured by her beauty .
Taking advantage of this , Mohini was giving the nectar only to Devtas .
A demon named Swarbhanu noticed this and sat in the queue of Devtas disguised as a God. Vishnu served him the nectar and he could drink a few drops of it.
In the meantime Surya and Chandra identified him as the demon and told this to Vishnu. Lord Vishnu used his Sudarshan and beheaded the demon.
However the demon had consumed the nectar so he remained alive but in two separated body parts.
It is believed that during eclipse when the sun or the moon appears to disappears, it is swallowed by Rahu and Ketu, to take their revenge.
Characterstics of Rahu and Ketu
According to Vedic astrology Rahu and Ketu both are strong planets and can have huge effect on the mental state of a person.
Rahu
Rahu is the planet that creates illusion and desires for material benefits. It is the cause of unsatisfaction and cravings in a person’s life.
Rahu is also known as the north node of the moon or the ascending node of the moon.
Rahu indicates paternal grandfather and does not rule over any zodiac sign.
Rahu symbolise a person whose actions are evil , who is always unsatisfied , who is born in lower caste, who always speak lies,
Ketu
In Vedic astrology , Ketu indicates maternal grandfather. Characterstics of Ketu are similar to Rahu . Native believes in falsehood and performs evil actions, likes to live in south direction and in a lonely place etc. Both the planets are considered as malefic and evil.
They can create depression ,confusion and mental imbalance if placed wrongly in the horoscope.
However they are important for material benefits. Planet Ketu is also prominent for spiritual and relgious benefits .