The Red Planet, Nergal, and the War God

The planet is conspicuously red to the unaided eye, an effect of iron oxide dust on its surface, and that colour is the origin of nearly all its associations: Nergal in Mesopotamia, god of plague, war and the underworld; Ares in Greece, the least loved of the Olympians; Mars in Rome, a considerably more respectable figure than Ares who was also an agricultural god and the father of Romulus, and after whom the month of March and the campaigning season were named. In Sanskrit the planet is Mangala or Kuja, and Indian astrology treats it with particular caution in questions of marriage, where the condition known as manglik is widely consulted. The eccentric orbit of Mars, which brings it much closer at some oppositions than others, produces the notable variations in its brightness that ancient observers recorded and that later helped Kepler derive his laws.

Mars's conspicuous colour and its unusually irregular motion, including retrograde loops more pronounced than those of the outer giants because its orbit lies just beyond Earth's, made it a body of particular concern in Babylonian celestial omen-reading centuries before Hellenistic astrology built the individual, chart-based nativity around it; those older Mesopotamian omens concerned war, plague and the fate of the state rather than any single person's temperament. The manglik or Kuja dosha assessment Indian astrology applies to Mars in the seventh, eighth or twelfth house from the Moon or ascendant has no equivalent malefic-marriage doctrine in the Hellenistic or Arabic traditions that otherwise share most of Mars's dignities with jyotisha, one of the clearer points where the Vedic elaboration struck out on its own.