In Vedic astrology, Rahu and Ketu are the sinful and shadow planets. If their position is not favorable in the horoscope, then the person's life can be very difficult. Rahu and Ketu have 5th, 7th, and 9th aspects and affect the house in which they are placed. Thus, if Rahu and Ketu and Ketu are in an inauspicious position in the horoscope, then these two together can directly affect 8 out of 12 houses of the horoscope.