The Astronomy of the Bible / An Elementary Commentary on the Astronomical References of Holy Scripture

by E. Walter Maunder

And so, in olden time, an eclipse of the sun came as an omen of terrible disaster, nay as being itself one of the worst of disasters. It came so to all nations but one. But to that nation the word of the prophet had come—

"Learn not the way of the heathen, and be not dismayed at the signs of heaven; for the heathen are dismayed at them."

God did not reveal the physical explanation of the eclipse to the Hebrews: that, in process of time, they could learn by the exercise of their own mental powers. But He set them free from the slavish fear of the heathen; they could look at all these terror-striking signs without fear; they could look with calmness, with confidence, because they looked in faith.

It is not easy to exaggerate the advantage which this must have given the Hebrews over the neighbouring nations, from a scientific point of view. The word of God gave them intellectual freedom, and so far as they were faithful to it, there was no hindrance to their fully working out the scientific problems which came before them. They neither worshipped the heavenly bodies nor were dismayed at their signs. We have no record as to how far the Hebrews made use of this freedom, for, as already pointed out, the Holy Scriptures were not written to chronicle their scientific achievements. But there can be no doubt that, given the leisure of peace, it is a priori more likely that they should have taught astronomy to their neighbours, than have learnt it even from the most advanced.

There must have been numberless eclipses of the moon seen in the ages during which the Canon of Holy Scripture was written. Of eclipses of the sun, total or very nearly total over the regions of Palestine or Mesopotamia, in the times of the Old Testament, we know of four that were actually seen, whose record is preserved in contemporaneous history, and a fifth that was nearly total in Judæa about midday.

The first of the four is recorded on a tablet from Babylon, lately deciphered, in which it states that on "the 26th day of Sivan, day was turned into night, and fire appeared in the midst of heaven." This has been identified with the eclipse of July 31, 1063 b.c., and we do not find any reference to it in Scripture.

The second is that of Aug. 15, 831 b.c. No specific record of this eclipse has been found as yet, but it took place during the lifetime of the prophets Joel and Amos, and may have been seen by them, and their recollection of it may have influenced the wording of their prophecies.

The third eclipse is recorded on a tablet from Nineveh, stating the coincidence of an eclipse in Sivan with a revolt in the city of Assur. This has been identified with the eclipse of June 15, 763 b.c.

The fourth is that known as the eclipse of Larissa on May 18, 603 b.c., which was coincident with the final overthrow of the Assyrian Empire, and the fifth is that of Thales on May 28, 585 b.c.

The earth goes round the sun once in a year, the moon goes round the earth once in a month, and sometimes the three bodies are in one straight line. In this case the intermediate body—earth or moon—deprives the other, wholly or partially of the light from the sun, thus causing an eclipse. If the orbits of the earth and moon were in the same plane, an eclipse would happen every time the moon was new or full; that is to say, at every conjunction and every opposition, or about twenty-five times a year. But the plane of the moon's orbit is inclined to the plane of the earth's orbit at an angle of about 5°, and so an eclipse only occurs when the moon is in conjunction or opposition and is at the same time at or very near one of the nodes—that is, one of the two points where the plane of the earth's orbit intersects the moon's orbit. If the moon is in opposition, or "full," then, under these conditions, an eclipse of the moon takes place, and this is visible at all places where the moon is above the horizon at the time. If, however, the moon is in conjunction, or "new," it is the sun that is eclipsed, and as the shadow cast by the moon is but small, only a portion of the earth's surface will experience the solar eclipse. The nodes of the moon's orbit are not stationary, but have a daily retrograde motion of 3´ 10·64´´. It takes the moon therefore 27^d 5^h 5^m 36^s (27·21222^d) to perform a journey in its orbit from one node back to that node again; this is called a Draconic period. But it takes the moon 29^d 12^h 44^m 2·87^s (29·53059^d) to pass from new to new, or from full to full, i. e. to complete a lunation. Now 242 Draconic periods very nearly equal 223 lunations, being about 18 years 10-1/3 days, and both are very nearly equal to 19 returns of the sun to the moon's node; so that if the moon is new or full when at a node, in 18 years and 10 or 11 days it will be at that node again, and again new or full, and the sun will be also present in very nearly its former position. If, therefore, an eclipse occurred on the former occasion, it will probably occur on the latter. This recurrence of eclipses after intervals of 18·03 years is called the Saros, and was known to the Chaldeans. We do not know whether it was known to the Hebrews prior to their captivity in Babylon, but possibly the statement of the wise king, already quoted from the Apocryphal "Wisdom of Solomon," may refer to some such knowledge.