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Evidence for or against "Worlds in Collision?"
Eclipses in Ancient Times
The following excerpts are taken from a much longer exchange published in Harper's magazine, June, 1951, between Velikovsky and the late Princeton University astronomer, John Q. Stewart. It gains currency owing to a question posed in a letter to the editor (Pensee, fall, 1972, 44). Copyright 1951 by Minneapolis Star and Tribune Co., Inc. Reprinted from Harper's magazine by special permission. Ed.
I. IMMANUEL VELIKOVSKY
On the basis of ancient records of eclipses, [critics] argue, precise calculations have established that, from the second millennium before the present era down to our time, the lunar eclipses have been retarded by the infinitesimal and almost exact interval of 1/1,000 of a second in a century; this very minute retardation is the result of tidal friction between the Earth and the Moon. The eclipses being so consistent throughout the millennia, there could have been no other changes in the rotation of the Earth nor in the revolution of the Moon during all this time.
It is a formidable argument, if it can stand. But does it not remind one of the "pyramidal inch," the minute measurements by which a British scholar once thought to extract hidden meanings from the Pyramid of Cheops? If the observations of the ancients can be fixed in time to the one-thousandth part of a second, then historical documents of the ancients must have very great observational value. Worlds in Collision is full of historical documents. However, historical testimony should not be trusted at all, we were told, even when hundreds of documents corroborate one another, if they are the basis for revolutionary conclusions affecting astronomy. Consequently, this early argument against my book disappeared from all subsequent criticism, to reappear in a much less formidable version. An astronomer from Michigan subsequently wrote: "Records of ancient eclipses go back to 2137 B.C. If the Earth's rotation had been disturbed only a fraction of the amount Velikovsky claims, these eclipses could not have taken place where and when they were recorded." A Harvard astronomer reduced the date 2137 B.C. to 1062 B.C.
If either of them were right, it would still be a devastating attack on the theory of great perturbations and changes in the position and movements of the Earth and the Moon. However, our knowledge of ancient eclipses comes mainly from Claudius Ptolemy of the second century of the present era, and his tables do not go back much farther than the beginning of the seventh century before the present era; they are, besides, primarily the result of retrograde calculations.
Wherever an eclipse or mention of a disturbance of the solar or lunar light is mentioned in any ancient document, theoretical times of eclipses are consulted by modern scholars, and various candidate dates of eclipses calculated for the first or second millennium are considered. The actual dates are not known; they are fixed only with the help of modern reckoning of the time when and the place where the eclipses are supposed to have taken place. Even for historical eclipses after 700 B.C., the exact dates are not established. Thus, the date of the most famous eclipse of antiquity, foretold by Thales of Miletus, and occurring during the battle between Alyattes the Lydian and Cyaxares the Median, is still debated and referred variously to May 28, 585 B.C. and September 30, 610 B.C. Earlier eclipses are arbitrarily assigned to dates when they are presumed to have happened. The last great perturbation of the Earth described in Worlds in Collision (pp. 227 ff.) took place on March 23, 687 B.C.
II. JOHN Q. STEWART
A second objection concerns the deceleration in the Earth's rotation, amounting to an increase in the length of the day of a thousandth of a second every century, and its relationship to ancient records of eclipses. In his article in this issue of Harper's, Velikovsky clearly makes a muddle of this issue. Of course neither the ancients nor ourselves ever timed a total eclipse of the Sun to an accuracy of a thousandth of a second, or to a whole second for that matter. But because successful computation of very ancient eclipses would be proof that neither Mars nor Venus nor any other massive bodies have since come close to the Earth, the reader is invited to consider this question in greater detail.
Velikovsky is quite wrong in saying that "our knowledge of ancient eclipses comes mainly from Claudius Ptolemy." Several modern scholars (notably Fotheringham) have examined Grecian, Babylonian, and Chinese records and listed passages which seem to describe solar eclipses. A brief survey of astronomical publications reveals at least three recorded total eclipses of the Sun before -687 (the supposed date of Velikovsky's last catastrophe) which have been considered by computers to fit the present motions. This evidence, reinforced by equally early records of lunar eclipses, proves or at any rate strongly suggests that no unaccountable disturbance of the motion of the Earth or Moon occurred in that year.
A solar eclipse is likely to be underscored in historical records only if it is a total eclipse, for only then is it spectacular. It is seen as total on each occasion from points on the Earth's surface lying within a band thousands of miles long and only a few score miles wide. The Moon's shadow, as it brushes the Earth from west to east, determines the band. It is enough to know from history only a very rough date- -the century, say--for as a rule total solar eclipses repeat at the same geographical locality only at long intervals. The date merely serves to identify which computed eclipse has been recorded in a given instance. The place of observation is the really important element; it establishes the longitude at which the band of totality crossed a given latitude. The observer knew where he was, whether or not he could measure the hour or the second.
An increase in the length of the day subsequent to the time of ancient eclipses would be shown by the fact that they were observed at points farther easterly than uncorrected computation had in retrospect suggested. The lagging behind of the rotating Earth, as compared with a perfect clock calibrated to the rate of rotation at some particular date, would increase with the square of the elapsed time as the years pass. Time lost is never made up again, while the rate of losing increases continually. This is the equivalent in rotational motion of the high-school physics principle that the distance moved by a falling body with constant acceleration increases with the square of the time.
Projected into the past, the Earth's rotation is seen to have been a very little faster than its present rate. The formula just mentioned shows that the cumulative difference is only 20 seconds as we work back the first century, but in twenty-five centuries it is the square of 25 times greater, 12,500 seconds, which is three hours and a half. This contrasts with an increase of only 1/40 second in the length of the day in twenty-five centuries. In the calculation of an eclipse which took place 2,500 years ago, this difference would be expressed in a displacement of longitude. We might find that an eclipse which would have been observed in Spain if the Earth had always been turning at its present rate is actually recorded not in Spain but far to the east near the Caspian Sea. This, in effect, is what actually happens, although the whole problem is much more complicated.
The most recent catastrophe suggested by Velikovsky, in the seventh century B.C., resulted from the alleged close approach of Mars. An approach of Mars to the Earth, by increasing the planet's gravitational pull at its lessened distance, would have disturbed the Moon's monthly motion around the Earth, and the Earth's motion in its own annual orbit. If the Moon rode at a distance only a few per cent farther away than now, for example, its angular diameter in our sky would be too small ever to hide the Sun. As Dr. Payne-Gaposchkin says, the thirty-six-day month mentioned by Velikovsky is incompatible with any total solar eclipses at all. But nearly any cosmic disturbance would be enough to render our present knowledge of Earth and Moon motions inadequate for eclipse computations before the supposed interference. The discrepancy between observation and calculation would become greater the further back in time we go. Nonetheless, the variation in eclipse records described above is the only one which has been found after known "perturbations" produced by the mutual gravitation of the celestial bodies have been allowed for.
The gravitational pull of the Sun and of each planet on the Earth and Moon is taken into careful account in such computations as these. The calculations are highly complex, achieving a product of successful intricacy which, in spite of the fact that it defies verbal analysis, is one of the most imposing demonstrations of the validity of celestial mechanics. Some idea of the degree of "intricacy" may be conveyed by Dr. Payne-Gaposchkin's statement that lunar theory alone recognizes 155 major periodic terms and over 500 smaller ones, which must be added together in the equation for the Moon's longitude, and about half as many in that for the Moon's latitude.
III. IMMANUEL VELIKOVSKY
In referring to three solar eclipses before 687 B.C., Professor Stewart must have in mind Fotheringham's lecture, "Historical Eclipses" (1921). The dates in question are 1062 B.C. in Babylonia, 776 B.C. in China, 763 B.C. in Assyria. Hundreds of eclipses obviously occurred in those countries during early centuries, but only one for each country is thought to be fixed.
(a) Babylonia. "On the 26th day of the month Siwan in the seventh year the day was turned to night. Heaven in flames." The century of the occurrence is still a matter of debate. Fotheringham chose 1062 B.C. There can be no solar eclipse on the 26th day of a lunar calendar month. Kugler explains the phenomenon:
The Earth was going through an immense train of small, dust-like, and also large meteorites. The meteoric dust created darkness; the larger meteorites became incandescent through friction in the atmosphere and put the sky in flames. (Sternkunde und Sterndienst in Babel, 11, 2, 373 n.)
(b) China. According to the Chinese book of songs, Shi-king, the sun was obscured. The place where the observation was made is not known. The calculation 776 B.C. is made on the authority of the astronomer Y-hang who lived a generation later (Gaubil, Histoire de l'astronomie chinoise, 1732, p. 81). In his day, in 721 B.C. an expected eclipse did not take place. Y-hang informed the Emperor that "the sky changed the course of the planet Venus" (Compare Varro on change of course and form of Venus, W. in C., p. 158).
(c) Assyria. A chronicle relates: "Insurrection in the city of Ashur. In the month Siwan the sun was obscured." The place of observation is not given. Nor the day of the month. The year is named in honor of a magistrate. By retrograde calculation an eclipse should have occurred on July 15, 763 B.C., if there were no changes. Placing the eclipse in 763 B.C. on July 15 and assigning the same year to the magistrate, an Assyrian chronology was built by reconstructing the lists of the magistrates. However, it required a change of 44 years in Biblical chronology.
Professor Stewart believes I confuse the argument of retardation in the Earth's rotation shown by ancient eclipses. The retardation was computed by Fotheringham from eclipses reaching back only to 585 B.C. Since the last catastrophe occurred 102 years earlier, Stewart's request that it shows an effect on retardation is without justification. Dr. Payne-Gaposchkin, and not I, wrote: "A very small, steady change in the length of the day, about 1/1000 of a second a century, has been measured." Stewart also finds the complexity of lunar motion "one of the most imposing demonstrations of the validity of celestial mechanics." S. Newcomb, however, on the basis of eclipses from Ptolemy to this century, found disturbing variations, and wrote:
I regard these fluctuations as the most enigmatical phenomenon presented by the celestial motions, being so difficult to account for by the action of any known causes, that we cannot but suspect them to arise from some action in nature hitherto unknown . . . It would be natural to associate them with the Sun's varying magnetic activity and the varying magnetism of the Earth. (Royal Astron. Soc. Monthly Notices, 1909.)
PENSEE Journal V