As per astrology sun & moon always transit in the 12 signs in Margi position (Truth is that Sun never transits) and Rahu & Ketu always transit in Vakri motion. Wherever a transiting planet is failed to maintains an appropriaate speed & degreecally distance from the Sun and gets out of the orbit it becomes retrograde and instead of following its route in the orbit it start coming towards the earth. Due to this it influence the earth and People etc at large. As far as the matter of good or bad condition it depends upon the planet who becomes retrograde, its placement, lordship etc in the horoscope.
Answered by
Arun Thhakur
at
8:27 PM on May 06, 2009