With reference to the plurality of inhabited worlds, it has been well said by the ancient writer Metrodorus (third century B.C.), “The idea that there is but a single world in all infinitude would be as absurd as to suppose that a vast field had been formed to produce a single blade of wheat.”[474] With this opinion the present writer fully concurs.
CHAPTER XXI
General
The achievements of Hipparchus in astronomy were very remarkable, considering the age in which he lived. He found the amount of the apparent motion of the stars due to the precession of the equinoxes (of which he was the discoverer) to be 59″ per annum. The correct amount is about 50″. He measured the length of the year to within 9 minutes of its true value. He found the inclination of the ecliptic to the plane of the equator to be 23° 51′. It was then 23° 46′—as we now know by modern calculations—so that Hipparchus’ estimation was a wonderfully close approximation to the truth. He computed the moon’s parallax to be 57′, which is about its correct value. He found the eccentricity of the sun’s apparent orbit round the earth to be one twenty-fourth, the real value being then about one-thirteenth. He determined other motions connected with the earth and moon; and formed a catalogue of 1080 stars. All this work has earned for him the well-merited title of “The Father of Astronomy.”[475]
The following is a translation of a Greek passage ascribed to Ptolemy: “I know that I am mortal and the creature of a day, but when I search out the many rolling circles of the stars, my feet touch the earth no longer, but with Zeus himself I take my fill of ambrosia, the food of the gods.”[476] This was inscribed (in Greek) on a silver loving cup presented to the late Professor C. A. Young, the famous American astronomer.[477]
Some curious and interesting phenomena are recorded in the old Chinese Annals, which go back to a great antiquity. In 687 B.C. “a night” is mentioned “without clouds and without stars” (!) This may perhaps refer to a total eclipse of the sun; but if so, the eclipse is not mentioned in the Chinese list of eclipses. In the year 141 B.C., it is stated that the sun and moon appeared of a deep red colour during 5 days, a phenomenon which caused great terror among the people. In 74 B.C., it is related that a star as large as the moon appeared, and was followed in its motion by several stars of ordinary size. This probably refers to an unusually large “bolide” or “fireball.” In 38 B.C., a fall of meteoric stones is recorded “of the size of a walnut.” In A.D. 88, another fall of stones is mentioned. In A.D. 321, sun-spots were visible to the naked eye.
Homer speaks of a curious darkness which occurred during one of the great battles in the last year of the Trojan war. Mr. Stockwell identifies this with an eclipse of the sun which took place on August 28, 1184 B.C. An eclipse referred to by Thucydides as having occurred during the first year of the Peloponnesian War, when the darkness was so great that some stars were seen, is identified by Stockwell with a total eclipse of the sun, which took place on August 2, 430 B.C.
A great eclipse of the sun is supposed to have occurred in the year 43 or 44 B.C., soon after the death of Julius Cæsar. Baron de Zach and Arago mention it as the first annular eclipse on record. But calculations show that no solar eclipse whatever, visible in Italy, occurred in either of these years. The phenomenon referred to must therefore have been of atmospherical origin, and indeed this is suggested by a passage in Suetonius, one of the authors quoted on the subject.