One similarity that exists between astrology and astronomy is the way in which they originated. Astronomy originated in the ancient world when people began to notice that heavenly bodies moved in a specific, consistent motion. The more people understood about the movement of the heavenly bodies, the easier it was for people to keep track of time. Astrology also had its birth in ancient times. People began to study the universe much more intensely as time progressed. In doing so people began to claim that the movement and position of the planets, predicted events on earth, and events in peoples lives. Therefore, although astronomy and astrology are very different now, they both began in ancient times.
Another similarity that exists between astrology and astronomy is that they both involve the study of the universe. However, both fields of study are very different by definition. Astrology is defined as "the theory that the planets, the sun, and the moon, as well ass the 12 zodiac signs combine in various ever-changing configurations with respect to each other and the local horizon to influence sub lunar events." (Pingree) Therefore, in ancient times it was believed that the configurations of planets in the universe had an impact of the lives of humans on earth. Astronomy is defined as "the study of the universe and the celestial bodies, gas, and dust within it. Astronomy includes observations and theories about the solar system, the stars, the galaxies, and the general structure of space." (Pasachoff)Therefore, although both astronomy and astrology are concerned with the study of the universe, they are very different in the way in which they study the universe.
Astronomers are concerned with the universe, with the universe being the "totality of all time, space, matter, and energy"(Chaisson & McMaillan 1) Whereas, astrologers make predictions about people's personal lives based the positions on the planets and stars.