The navagrahas form the basis of ancient Hindu astronomy. They consist of nine celestial bodies. There are seven from the solar system namely the Surya or the sun, Chandra or the moon, Mangal or Mars, Budha or Mercury, Brihaspati or Jupiter, Shukra or Venus and Shani or Saturn. These seven planets are considered divine and worshipped as deities. The other two are the demons, Rahu and Ketu, who got in by trickery. They could be a reference to comets or the darker planets of Neptune and Pluto. Collectively these planets, depending on their position at birth, influence a number of outcomes for the world in general and for individuals in particular. These influences can be positive or negative and there is a whole science dedicated to drawing birth charts and circumventing these unfavorable influences as well as enhancing the beneficial influences. The role of Shani, Rahu and Ketu are of particular importance because of their potential to cause harm. Each of the nine bodies has different characteristics but on the whole they have certain prominent roles. The sun is important for overall health. The moon controls mental stability and determines success as well as fertility. Mangal controls wealth and prosperity as well as the muscular system of the body. Budha reflects the nervous system, intelligence and communication and is the knowledge provider. Brihaspati determines the importance of education in our life as well as spirituality and love. Shukra influences the finer aspects of life such as art, music, luxurious living and fortune. A beneficial Shani implies longevity and shows the path of renunciation but if it is a negative influence, prolongs misery and grief. Rahu provides strength but in a negative situation obstructs success and Ketu can add prosperity but is known to reflect the consequences of karma whether good or bad.