Graha means ‘planet’ and it has great significance in astrology. According to Indian astrology, there are nine planets having some essential properties. The moving of planets through the chart wheel of a person can influence his or her life.
When these planets come together with the rashies (signs) and houses (Bhavas) they occupy, they change their color, leading to different behavior, at different time of births.
At certain points, the planets gain strength and behave differently in different signs and houses. Depending upon the house they own in the astrology chart, some planets become Yogakaraka (good) or maraka (harmful) for the person.
The nine planes as per Indian astrology include Sun, Moon, Mars, Mercury, Jupiter, Venus (Shukra), Saturn, Rahu and Ketu.
[Source (37) 17-Apr-05]