A central principle of Yoga and Vedic Astrology is the cycle of human birth, death and rebirth, as the soul’s journey towards the realization of its cosmic roots. With each successive birth the desires of the soul to experience all aspects of life evolve until all desires have been transmuted (not suppressed) and surrendered. The desire that propels the soul to take birth on the physical plane is Rahu (north node) and the completion of the desire is Ketu (south node). When all longings cease and everything is embraced as an aspect of the divine, the journey is complete, and the soul merges back into its source.