Sir, - Your Science Today page of October 9th featured an article by Fintan Gibney entitled "Discovering methods to cleverly conceal", which contains two statements with which I would take issue. For one, it is stated that "Galileo can be excused for concealing certain discoveries regarding planetary motions, given that the Catholic Church was opposed to the Copernican model of the solar system." Secondly, Mr Gibney presumes that Johannes Kepler and other 17th century Protestants were "not subject to the anti-intellectualism of the Roman Church at the time".
In fact, in the wake of his telescopic discoveries, Galileo enjoyed the almost universal goodwill of the Catholic hierarchy. He made a visit to Rome in 1611, where he was feted by cardinals, and granted a private audience by Pope Paul V, who promised his personal support. What soured this relationship was his insistence on one-upmanship, and the fact that he published a work on cosmology 20 years later that contained a thinly disguised insult to his long-time friend, Pope Urban VIII.
The Catholic Church was not at that time opposed to heliocentrism. In his time, Copernicus had feared not the wrath of the Church, but the ridicule of Aristotelian acadmeics. Copernicus's theory (1543) drew a furious response from Martin Luther and Philipp Melanchton, who regarded heliocentricity as blasphemous. Even by 1600, Kepler had to flee Protestant Europe and seek the protection of the Jesuits for proposing a Sun-centred description of planetary motion.
That Venus had moon-like phases, which Galileo observed in 1611, was indeed compelling evidence against the Ptolemaic system. But this system had already for many years been superseded by the cosmology of Tycho Brahe, that held the Earth to be immobile, the Sun to be in orbit about it, and several of the planets to be in orbit about the Sun. A crescent Venus tells you only the relative positions of it, the Earth and Sun, not which one is at rest. Galileo never tackled this, or several other valid objections to Copernicus. Alas, the truth, be it historical or scientific in nature, is often tiresomely complex. - Yours, etc.,
Emmet Mordaunt, PRO, Astronomy Ireland, PO Box 2888, Dublin 1.