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

by E. Walter Maunder

Its core or inner nucleus is not accessible to observation, its nature and constitution being a mere matter of inference. The "photosphere" is a shell of incandescent cloud surrounding the nucleus, but the depth, or thickness of this shell is quite unknown. The outer surface—which we see—of the photosphere is certainly pretty sharply defined, though very irregular, rising at points into whiter aggregations, called "faculæ," and perhaps depressed at other places in the dark "spots." Immediately above the photosphere lies the "reversing layer" in which are found the substances which give rise to the gaps in the sun's spectrum—the Fraunhofer lines. Above the "reversing layer" lies the scarlet "chromosphere" with "prominences" of various forms and dimensions rising high above the solar surface; and over, and embracing all, is the "corona," with its mysterious petal-like forms and rod-like rays.

The great body of the sun is gaseous, though it is impossible for us to conceive of the condition of the gaseous core, subjected, as it is, at once to temperature and pressure both enormously great. Probably it is a gas so viscous that it would resist motion as pitch or putty does. Nor do we know much of the nature of either the sun-spots or the solar corona. Both seem to be produced by causes which lie within the sun; both undergo changes that are periodical and connected with each other. They exercise some influence upon the earth's magnetism, but whether this influence extends to terrestrial weather, to rainfall and storms, is still a matter of controversy.

The sun itself is distant from the earth in the mean, about 92,885,000 miles, but this distance varies between January and June by 3,100,000 miles. The diameter of the sun is 866,400 miles, but perhaps this is variable to the extent of some hundreds of miles. It would contain 1,305,000 times the bulk of the earth, but its mean density is but one-quarter that of the earth. The force of gravity at its surface is 27-1/2 times that at the surface of the earth, and it rotates on its axis in about 25 days. But the sun's surface does not appear to rotate as a whole, so this time of rotating varies by as much as two days if we consider a region on the sun's equator or at a distance from it of 45°. The intensity of sunlight at the surface of the sun is about 190,000 times that of a candle-flame, and the effective temperature of the solar surface is eight or ten thousand degrees centigrade.

Such are some of the facts about the sun that are received, or, as it would be technically expressed, "adopted" to-day. Doubtless a very few years will find them altered and rendered more accurate as observations accumulate. In a few hundred years, knowledge of the constitution of the sun may have so increased that these data and suggestions may seem so erroneous as to be absurd. It is little more than a century since one of the greatest of astronomers, Sir William Herschel, contended that the central globe of the sun might be a habitable world, sheltered from the blazing photosphere by a layer of cool non-luminous clouds. Such an hypothesis was not incompatible with what was then known of the constitution of the heavenly bodies, though it is incompatible with what we know now. It was simply a matter on which more evidence was to be accumulated, and the holding of such a view does not, and did not, detract from the scientific status of Sir William Herschel.

The hypotheses of science require continual restatement in the light of new evidence, and, as to the weight and interpretation to be given to such evidence, there is continual conflict—if it may so be called—between the old and the new science, between the science that is established and the science that is being established. It is by this conflict that knowledge is rendered sure.

Such a conflict took place rather more than 300 years ago at the opening of the Modern Era of astronomy. It was a conflict between two schools of science—between the disciples of Aristotle and Claudius Ptolemy on the one hand and the disciples of Copernicus on the other. It has often been represented as a conflict between religion and science, whereas that which happened was that the representatives of the older school of science made use of the powers of the Church to persecute the newer school as represented by Galileo. That persecution was no doubt a flagrant abuse of authority, but it should be impossible at the present day for any one to claim a theological standing for either theory, whether Copernican or Ptolemaic.

So long as evidence sufficient to demonstrate the Copernican hypothesis was not forthcoming, it was possible for a man to hold the Ptolemaic, without detracting from his scientific position, just as it is thought no discredit to Sir William Herschel that he held his curious idea of a cool sun under the conditions of knowledge of a hundred years ago. Even at the present day, we habitually use the Ptolemaic phraseology. Not only do we speak of "sunrise" and "sunset," but astronomers in strictly technical papers use the expression, "acceleration of the sun's motion" when "acceleration of the earth's motion" is meant.

The question as to whether the earth goes round the sun or the sun goes round the earth has been decided by the accumulation of evidence. It was a question for evidence to decide. It was an open question so long as the evidence available was not sufficient to decide it. It was perfectly possible at one time for a scientific or a religious man to hold either view. Neither view interfered with his fundamental standing or with his mental attitude towards either sun or earth. In this respect—important as the question is in itself—it might be said to be a mere detail, almost a matter of indifference.

But it is not a mere detail, a matter of indifference to either scientist or religious man, as to what the sun and earth are—whether he can treat them as things that can be weighed, measured, compared, analyzed, as, a few pages back, we have shown has been done, or whether, as one of the chief astrologers of to-day puts it, he—

"Believes that the sun is the body of the Logos of this solar system, 'in Him we live and move and have our being.' The planets are his angels, being modifications in the consciousness of the Logos,"