Astrology consists of several pseudoscientific systems of divination based on the premise that there is a relationship between astronomical phenomena and events in the human world. Many cultures have attached importance to astronomical events, and the Indians, Chinese, and Mayans developed elaborate systems for predicting terrestrial events from celestial observations. In the West, astrology most often consists of a system of horoscopes purporting to explain aspects of a person'spersonality and predict future events in their life based on the positions of the sun, moon, and other celestial objects at the time of their birth. The majority of professional astrologers rely on such systems.
Throughout most of its history, astrology was considered a scholarly tradition. It was accepted in political and academic contexts, and was connected with other studies, such as astronomy, alchemy, meteorology, and medicine. At the end of the 17th century, new scientific concepts in astronomy and physics (such as heliocentrism and Newtonian mechanics) called astrology into question. Astrology thus lost its academic and theoretical standing, and common belief in astrology has largely declined. Astrology has been rejected by the scientific community as a pseudoscience, having no validity or explanatory power for describing the universe. Among other issues, there is no proposed mechanism of action by which the positions and motions of stars and planets could affect people and events on Earth that does not contradict well understood basic aspects of biology and physics. Scientific testing of astrology has found no evidence to support any of the premises or purported effects outlined in astrological traditions. In one study, participating astrologers attempting to match natal charts with profiles generated by a psychological inventory produced results not significantly at variance with random chance.