Page:Popular Science Monthly Volume 78.djvu/332

322 that he greatly simplified the theory of planetary motion by this step. . . which he worked out mathematically. . . and, that by means of his simpler theory and more exact planetary tables, he reduced to some sort of order the confused chaos of the Ptolemaic system, whose accumulations of complexity and of outstanding errors threatened to render astronomy impossible by the mere burden of its detail. There are many imperfections in his system, it is true, but his great merit is that he dared to look at the facts of nature with his own eyes unhampered by the prejudice of centuries. A system, venerable with age and supported by great names, was universally believed and had been believed for centuries. To doubt this system, and to seek after another and better one, at a time when all men's minds were governed by tradition and authority, and when to doubt was sin—this required a great mind and a high character. Such a mind and such a character had this monk of Franenburg.

Mr. E, J. C. Morton in a biography of Copernic says:

 ". . . like some iron peak, by the Creator Fired with the red glow of the rushing morn."

It is not to be supposed that there were not weighty objections to be urged against the Copernican system. Of these three may be noted:

1. If it be true that the earth moves, why do not the configurations of the stars change with the changing seasons? It is evident that the grouping of the stars depends upon the distance of the earth from them, and if the earth moves the groups of stars in front of the earth's motion should appear to open out while those behind should appear to close up. We now know the correct answer, that is, that the 184 millions of miles making up the diameter of the earth's orbit is lost in the immensity of stellar space and its effect can only be detected by the most refined of modern methods,

2. If the earth moves about the sun. Mercury and Venus should show phases as does the moon.

The only answer Copernicus could make was that, wore the powers of man's eyesight sufficiently increased, this would doubtless be found to be the case. Seventy years later, Galileo furnished the required proof.

Before looking so far ahead, two important workers must be noted. The first of these is the Danish astronomer, Tycho Brahé (1545-1601), who is well called the father of instrumental astronomy. His aid in the solution of the present problem did not consist in the advocacy of the Copernican system—for he rejected it—but in his patient, faithful gathering of data. His tables of planetary motions and his star tables were the most extensive and the most accurate of his time. Even when