Physical Science in the Time of Nero: Naturales Quaestiones (1910) - Page 25

CHAP.		PAGE
X.	The slowness and steadiness of a comet could not be accounted for by this assumption, nor could its general behavior and shape.	281
XI.	We must look for another explanation. Now, comets appear in all quarters of the sky. Whatever divisions the Greeks may have made, they all share one origin. Some of the ancients thought they were due to the union of two planets.	283
XII.	Again, the facts do not align. Comets and planets appear simultaneously. A conjunction is momentary, while a comet sometimes lasts for six months. Planets do not pass far beyond the ecliptic, but comets appear in every part of the sky. There are other objections as well.	284
XIII.	Artemidorus believes the firmament is solid and has openings for the stars. He claims comets are accidental planets or formed by their conjunctions. His account is a tissue of barefaced falsehoods.	286
XIV.	How would a solid firmament be supported? No feasible explanation can be offered. Besides, the number of stars is so great—and they might all be "wanderers" if an indefinite number are—that there must be innumerable conjunctions (i.e., comets). But, as a matter of fact, comets are rare.	287
XV.	Furthermore, the huge comets from the times of Demetrius and Attalus would require scores of planetary conjunctions to form them.	288
XVI.	Ephorus, a mere chronicler who holds this view, has nothing to support him. Like others of his group, he tries to embellish his work by narrating marvels. Why did he not tell us what the two stars were into which the comet supposedly resolved itself?	289
XVII.	Apollonius of Myndus holds that the comet is a true star (planet) with an erratic course, visible only when it approaches the lower part of its orbit. He discusses the different colors of comets.	290
XVIII.	But comets do not wax and wane as they approach and recede like planets. Nor do their orbits lie within the ecliptic. Besides, we can see through a comet, but not through a true star (planet).	291
XIX.	Zeno the Stoic thinks the light of converging stars creates the appearance of a longer star. Others hold modified versions of this opinion or analogous views.	291
XX.	Most of the Stoics hold that comets are fleeting and attribute them to the friction of the air. Various phenomena are considered analogous.	292
XXI.	Their methods of accounting for the varieties of orbits in comets.	293
XXII.	I do not agree with any school. Reasons for this.	295
XXIII.	Further arguments showing the difference between ordinary fires and comets.	295
XXIV.	There may be many stars in the universe whose paths have not been traced; comets are such stars. No satisfactory explanation has been given of the mind, yet its existence is not doubted.	297
XXV.	Comets are not yet fully understood. Many things fall into this same category. A future age will be amazed at our ignorance of such matters.	298