He demonstrated the rotation of the satellites of Jupiter round the planet, and gave rough predictions of their configurations, proved the rotation of the sun on its axis, established the general truth of the Copernican system as compared with that of Ptolemy, and fairly routed the fanciful dogmas of the philosophers.
On the Copernican change the heavenly bodies were recognized as concrete and yet subject to calculable law.
Henceforth the Aristotelian logic, the genuine no less than the traditional, was to lie on the other side of the Copernican change.
These are, briefly speaking, the decay of those great fabrics, church and empire, which ruled the middle ages both as ideas and as realities; the development of nationalities and languages; the enfeeblement of the feudal system throughout Europe; the invention and application of paper, the mariner's compass, gunpowder, and printing; the exploration of continents beyond the ocean; and the substitution of the Copernican for the Ptolemaic system of astronomy.
His commentary on Manilius is really a treatise on the astronomy of the ancients, and it forms an introduction to the De emendatione temporum, in which he examines by the light of modern and Copernican science the ancient system as applied to epochs, calendars and computations of time, showing upon what principles they were based.
The significance of the Copernican system, as the total overthrow of the traditional conception of the universe, dawned on all educated men.
Blount adopted and expanded Hobbes's arguments against the Mosaic authorship of the Pentateuch; and, mainly in the words of Burnet's Archeologiae philosophicae, he asserts the total inconsistency of the Mosaic Hexaemeron with the Copernican theory of the heavens, dwelling with emphasis on the impossibility of admitting the view developed in Genesis, that the earth is the most important part of the universe.
He was also the first advocate of Copernican views in England, and he concluded that the fixed stars are not all at the same distance from the earth.
Bellarmine did not proscribe the Copernican system, as has been maintained by Reusch (Der Process Galilei's and die Jesuiten, Bonn, 1879, p. 125); all he claimed was that it should be presented as an hypothesis until it should receive scientific demonstration.
The Tabulae Prutenicae, calculated on Copernican principles by Erasmus Reinhold (1511-1553), appeared in 1551.
Galileo seems, at an early period of his life, to have adopted the Copernican theory of the solar system, and was deterred from avowing his opinions - as is proved by his letter to Kepler of August 4, 1 597 - b y the fear of ridicule rather than of persecution.
An illustration is, with the general run of mankind, more powerful to convince than an argument; and the cogency of the visible plea for the Copernican theory offered by the miniature system, then first disclosed to view, was recognizable in the triumph of its advocates as well as in the increased acrimony of its opponents.
In December 1613 a Benedictine monk named Benedetto Castelli, at that time professor of mathematics at the university of Pisa, wrote to inform Galileo of a recent discussion at the grandducal table, in which he had been called upon to defend the Copernican doctrine against theological objections.
The Saggiatore was printed at Rome in October 1623 by the Academy of the Lincei, of which Galileo was a member, with a dedication to the new pope, Urban VIII., and notwithstanding some passages containing a covert defence of Copernican opinions, was received with acclamation by ecclesiastical, no less than by scientific authorities.
The ironical submission with which it opened, and the assumed indetermination with which it closed, were hardly intended to mask the vigorous assertion of Copernican principles which formed its substance.
On the 21st of June he was finally examined under menace of torture; but he continued to maintain his assertion that after its condemnation by the Congregation of the Index, he had never held the Copernican theory.
Of his two capital errors, regarding respectively the theory of the tides and the nature of comets, the first was insidiously recommended to him by his passionate desire to find a physical confirmation of the earth's double motion; the second was adopted for the purpose of rebutting an anti-Copernican argument founded on the planetary analogies of those erratic subjects of the sun.
It is not too much to say that the final triumph of the Copernican system was due in larger measure to his labours in this department than to his direct arguments in its favour.
At Liege (September 1633), with the words " although he professes that the [Copernican] theory was only adopted by him as a hypothesis."
3 The Copernican theory is rejected in name, but retained in substance.
But it is a plain finding of history that he has brought no " Copernican revolution " 4 to their minds.
As results of Roberval's labours outside the department of pure mathematics may be noted a work on the system of the universe, in which he supports the Copernican system and attributes a mutual attraction to all particles of matter; and also the invention of a special kind of balance which goes by his name.
But his assent to this was only extracted from him in 1540 by the importunities of his friends, especially of his enthusiastic disciple George Joachim Rheticus (1514-1576), who printed, in the Narratio prima (Danzig, 1540), a preliminary account of the Copernican theory, and simultaneously sent to the press at Nuremberg his master's complete exposition of it in the treatise entitled De revolutionibus orbium coelestium (1543).
Being greatly attracted by the new Copernican theory, he resigned the professorship in 1539, and went to Frauenberg to associate himself with Copernicus, and superintended the printing of the De Orbium Revolutione which he had persuaded Copernicus to complete.
He also published Narratio de Libris Revolutionum Copernici (Gedenum, 1540), which was subsequently added to editions of Copernicus's works; and Ephemerides until 1551, which were founded on the Copernican doctrines.
In Oxford he was allowed to hold a disputation with some learned doctors on the rival merits of the Copernican and so-called Aristotelian systems of the universe, and, according to his own report, had an easy victory.
The Cena de le Ceneri, or Ash Wednesday conversation, devoted to an exposition of the Copernican theory, was printed in 1584.
The " Copernican revolution " which he claimed to have effected may be said to have become the starting-point of all modern philosophy.
A brilliant examination for the degree of bachelor procured him, in 1588, admittance on the foundation to the university of Tubingen, where he laid up a copious store of classical erudition, and imbibed Copernican principles from the private instructions of his teacher and life-long friend, Michael Maestlin.
As early as 1573, Thomas Digges had suggested that this theory should necessitate a parallactic shifting of the stars, and, consequently, if such stellar parallaxes existed, then the Copernican theory would receive additional confirmation.
- Gilbert was probably led to study the phenomena of the attraction of iron by the lodestone in consequence of his conversion to the Copernican theory of the earth's motion, and thence proceeded to study the attractions produced by amber.
The Copernican theory of the solar system - that the earth revolved annually about the sun - had received confirmation by the observations of Galileo and Tycho Brahe, and the mathematical investigations of Kepler and Newton.