Rahu or Dragon’s Head or North Node represents foreigners, foreign countries, foreign travel, engineering and the technical trades, smoke, old men, grandparents, theft, gambling, drinking, nonconformists, the underworld and the bad elements in the society. Its color is black; metal is mixed-metal and gem is Gomedh. Rahu takes approximately 1-1/2 years to travel a sign and hence completes the round of the zodiac in 18 years.