By Ron Cowen
On Oct. 10, 1604, a young assistant to the German astronomer Johannes Kepler looked up in the sky and saw a brilliant light that had never been there before. Located in the serpent-bearer constellation Ophiuchus, the object shone brighter than any other star in the heavens. Over the next few nights, the body grew even more luminous, rivaling the glow of the solar system’s biggest planet, Jupiter. Kepler himself got his first clear view on Oct. 17. Over the next year, he charted the course of the “new star” with naked-eye observations because the telescope hadn’t yet been invented.
Kepler’s book, De Stella Nova in Pede Serpentarii (On the New Star in Ophiuchus’ Foot), was read by noblemen and others eager to learn about the brilliant new light in the sky. Although Kepler speculated that the star’s appearance, which coincided both in time and sky location with the conjunction of Mars, Jupiter, and Saturn, might portend some important historical event, he admitted that he couldn’t explain the celestial phenomenon.