THE PERIL OF THE COMET
It was Edmund Halley who first revealed a source of danger from Comets, of which even medieval superstition had never dreamed.
While he was patiently plotting out the orbit of the Comet of 1680, which had inspired no little dismay among his contemporaries, Halley found that the Earth’s orbit had been approached by the Comet within four thousand miles—half the diameter of the Earth.
If the Earth had been struck by that fiery wanderer?
None had ever thought of the possibility.
Halley began to do some mathematical figuring, and decided that, if a Comet’s mass were comparable with that of the Earth, our year would have been changed in length because the Earth’s orbit would have been altered. He also speculated what would happen to the Earth, and reached this conclusion:
“If so large a body with so rapid a motion were to strike the Earth—a thing by no means impossible—the shock might reduce this beautiful world to its original chaos.”
Halley even thought it probable that the Earth had actually been struck by a Comet at some remote period, struck obliquely, moreover, so that the axis of rotation had been changed. Thus he was led to infer that possibly the North Pole had once been at a point near Hudson’s Bay, and that the rigour of North America’s climate might thus be accounted for.
The seed which was thus sown by Halley has borne fruit. In Halley’s own time, learned men were brooding over the ultimate destruction of the Earth by collision with a Comet.
Dr. Whiston, who succeeded Newton at Cambridge in the Lucasian chair of mathematics, was sure that a Comet caused the Deluge, and went so far as to prophesy that a Comet, as it passed us on its outward course from the Sun, would ultimately bring about a “General Conflagration,” and thus envelope the Earth in flames.