Is the report true? And if so, of what type are these newly discovered heavenly bodies? Are they companions of fixed stars, or do they belong to our solar system? Herr Wackher, though a Catholic, holds to the view of the misfortunate Bruno, that the stars are suns, infinite in number, which fill the infinite space, and Galileo's discovery, he believes, is proof of it, the four new bodies being companions of fixed stars: in other words, that it is another solar system that the Paduan has found. To me, however, as you know, an infinite universe is unthinkable. Also I consider it impossible that these are planets circling our sun, since the geometry of the world set forth in my Mysterium will allow of five planets in the solar system, and no more. Therefore I believe that what Galileo has seen are moons circling other planets, as our moon circles the earth. This is the only feasible explanation.
Perhaps you, closer to the scene of these discoveries, already have heard the correct explanation-perhaps even you have witnessed the new phenomena! Ah, to be in Italy. The Tuscan envoy, de Medici, who gave this news to Wackher, has presented to the Emperor a copy of Galileo's book. I hope soon to get my hands on it. Then we shall see!
Write, tell me all the news! Kepler
PragueApril 1610
George Fugger, legatus imperatorius: at Venice
Lest silence amp; delay should make you believe that I agree with all you have to say in your latest letter, and since your position is peculiarly relevant in these matters, Galileo being in the employ of the Venetian Republic, I thought it prudent to interrupt my present studies and write to you straightway. Believe me, my dear Sir, I am deeply touched by your remarks regarding the claims to pre-eminence as between the Paduan amp; myself. However, I am not running a foot-race with him, that I should want for cheering amp; partisan broadcasting. Certainly, it is true what you say, that he urgently requires in these discoveries amp; claims of his the blessing of the Imperial Mathematician; and perhaps indeed this is, as you maintain, the only reason he has approached me. But why not? Some dozen years ago, before I was famous, and my Mysterium had just been published, it was I approaching him. True, he did not at that time make any great effort on my behalf. Perhaps he was too much taken up with his own work, perhaps he did not think much of my little book. Yes, I know his reputation for arrogance amp; ingratitude: what of it? Science, Sir, is not like diplomacy, does not progress by nods amp; winks amp; well-wrought compliments. It has always been my habit to praise what, in my opinion, others have done well. Never do I scorn other people's work because ofjealousy, never do I belittle others' knowledge when I lack it myself. Likewise I never forget myself when I have done something better, or discovered something sooner. Certainly, I had hoped for much from Galileo when my Astronomia nova appeared, but the fact that I received nothing will not prevent me now from taking up my pen so that he should be armed against the sour-tempered critics of everything new, who consider unbelievable that which is unknown to them, and regard as terrible wickedness whatever lies beyond the customary bounds of Aristotelian philosophy. I have no wish to pull out his feathers, as you put it, but only to acknowledge what is of value, and question that which is doubtful.
No one, Excellency, should allow himself to be misled by the brevity amp; apparent simplicity of Galileo's little book. The Sidereus nuncius is highly significant amp; admirable, as even a glance through its pages will show. It is true that not everything in it is wholly original, as he claims-the Emperor himself has already turned a spyglass upon the moon! Also, others have surmised, even if they have not provided proof, that the Milky Way would, on closer inspection, dissolve into a mass of innumerable stars gathered together in clusters. Even the existence of planetary satellites (for this is, I believe, what his four new planets are, in fact) is not so amazing, for does not the moon circle the earth, and hence why should not the other planets have their moons? But there is a great difference between speculating on the existence of a myriad of invisible stars, and noting their positions on a map; between peering vacantly through a lens at the moon, and announcing that it is composed not of the quinta essentia of the schoolmen, but of matter much like that of the earth. Copernicus was not the first to hold that the sun sits at the centre of the world, but he was the first to build around that concept a system which would hold good mathematically, thus putting an end to the Ptolemaic age. Likewise Galileo, in this pamphlet, has set down clearly amp; calmly (and with a calm precision from which, I ruefully admit, I could learn much!) a vision of the world which will deliver such a blow to the belly of the Aristotelians that I think they will be winded for a long time to come.
The Sidereus nuncius is much talked about at court, as by now I suppose it is everywhere. (Would that the Astronomia nova had attracted such attention!) The Emperor graciously let me glance through his copy, but otherwise I had to contain myself as best I could until a week ago, when Galileo himself sent me the book, along with a request for my opinion on it, which I suppose he wishes to publish. The courier returns to Italy on the 19th, which leaves me just four days in which to complete my reply. Therefore I must close now, in the hope that you will forgive my haste-and also that you will not take amiss my response above to your touching amp; much appreciated gestures of support for me. In these matters of science, it is a question, you see, not of the individual, but of the work. I do not like Galileo, but I must admire him.
By the way, I wonder, during your recent time in Rome, did you see or hear anything of Tycho's dwarf, and his companion, the one called Felix? I would have news of them, if you know any.
I am, Sir, your servant, Johannes Kepler
Aedes Cramerianis
Prague
March 1611
Dr Johannes Brengger: at Kaufbeuren
Everything darkens, and we fear the worst. In the little world of our house, a great tragedy has befallen, which, in the morbid confusion of our grief, we cannot help but believe is in some way connected with the terrible events in the wider world. I think there are times when God grows weary, and then the Devil, seizing his chance, comes flying down upon us with all his fury amp; cruel mischievousness, wreaking havoc high amp; low. How far away now, my dear Doctor, seem those happier days when we corresponded with such enthusiasm amp; delight on the matter of our newborn science of optics! Thank you for your latest letter, but I fear I am unable at present to engage the interesting questions which you pose-another time, perhaps, I shall turn my mind upon them, and reply with the vigour they demand. I have not the heart for work now. Also much of my time is consumed by duties at court. The Emperor's eccentricities have come to seem more amp; more like plain insanity. He immures himself in the palace, hiding from the sight of his loathed fellow men, while in the meantime his realm falls asunder. Already his brother Matthias has dispossessed him of Austria, Hungary amp; Moravia, and is even now preparing to take over what is left. Throughout last summer and into the autumn, a congress of princes was held here in the city, which urged reconciliation between the brothers. Rudolph, however, despite his whimsy amp; his peculiarities, displays an iron stubbornness. Thinking to curb both Matthias amp; the princes, and also perhaps to set aside the religious freedoms wrested from him in the Royal Charter by the Lutheran Representatives here, he plotted with his kinsman Leopold, Bishop of Passau amp; brother to the poisonous Archduke Ferdinand of Styria, my old enemy. Leopold, of course, as vile amp; treacherous as the rest of his family, turned his army against us here, and has occupied part of the city. Bohemian troops massed against him, and frightful excesses by both sides are reported. Matthias, it is said, is now on his way here with an Austrian army, at the request of the Representatives-and of Rudolph himself! There can be only one result of all this, that the Emperor will lose his throne, and so I have begun to look elsewhere for a refuge. Certain influential people have urged me to come to Linz. For my own part, I cannot help but look with longing toward my native Swabia. I have sent a petition to the Duke of Württemberg, my sometime patron, but I have scant faith in him. Hard it is to know that one is not wanted in one's homeland! Also I have been offered Galileo's old chair at Padua, following his departure for Rome. Galileo has himself recommended me. The irony of this does not escape me. Italy -I do not relish the thought. Linz would seem, therefore, the most promising prospect. It is a narrow amp; provincial town, but there are people there whom I know, as well as a special friend. My wife would be happy to leave Prague, which she has never liked, and return to her native Austria. She has been most ill, with Hungarian fever amp; epilepsy. She bore these afflictions with fortitude, and all might have been well with her, had not our three children shortly thereafter been seized with the smallpox. The eldest one and the youngest survived, but Friedrich, our darling son, succumbed. He was six. It was a hard death. He was a fair child, a hyacinth of the morning in the first days of spring, our hope, our joy. I confess, Doctor, I fail sometimes to understand the ways of God. Even as the boy lay on his death bed, we could hear from across the city the noise of battle. How may I adequately express to you my feelings? Grief such as this is like nothing else in the world. I must close now.