Deluge and Comet
The idea that a comet heralded the Deluge was not new with William Whiston: it is found in several earlier authors, the so-called cometographers and chronologists of the seventeenth century. But they only described the appearance of the comet at the time of the Deluge as a matter of fact, and did not deduce any theory from it. No causal relation was seen: it was more in the nature of a coincidence. New in Whiston was the identification of the comet of 1680 as the comet of the Deluge, and the perturbatory effects on the position and motion of our planet, ascribed by him to the activities of the comet; finally, his general theory that the Earth itself was once a comet.
The author whom Whiston names as his source was J. Hevelius, whose Cometographia was published in 1668. Apparently Whiston did not go further back to the sources of Hevelius: to Abraham Rockenbach (15 -16 ), Seth Calvisius (1556-1615), Henricus Ecstormius, Christopher Helvicus (1581-1617) and David Herlicius (1557-1636).(1) Abraham Rockenbach was a scholar of the late Renaissance, a man of broad interests, already evident from that fact that he occupied both, the chair of Greek and of Mathematics at the University of Frankfurt, and later taught law and became Dean of the Philosophical College at that University. In 1602 he published a short treatise in Latin, De cometis tractatus novus methodicus, and in it he had the following entry concerning the Deluge:
Rockenbach lived and wrote nearly a hundred years before Whiston. What were Rockenbachs sources? He did not let us know. He referred to them at the beginning of his treatise, claiming that it was based on information ex probatissimis & antiquissimis veterum scriptoribus"from the most trustworthy and the most ancient of the early writers. We have already had occasion to quote from Rockenbach in connection with the comet that shone during the Exodus.(3) There he refers only to Pliny, although he probably used other sources besides: Lydus, Servius, Hephaestion, and Junctinus wrote about comets, and Servius mentions also the writings of Campester and Petosiris.
Although we may never be certain of the sources on which Abraham Rockenbach and other cometographers drew in mentioning a comet in connection with the Deluge, the great medieval rabbinical authority Rashi was probably among them.(4) Rashi wrote concerning Khima, a celestial body mentioned in Job 9:9 and 38:31, and in Amos 5:8, that it is a star with a tail, or a comet. In the Talmud, Khima is associated with the Deluge, and this seems to have been the source of the cometographers assertion that a comet appeared in conjunction with that event.
The question now is, what was Khima, and what was its role in the Deluge? Was it really a comet as Rashi thought?