In terms of the public reaction it received, the Astronomia Nova didn't fare much better than the Mysterium Cosmographicum. Once again, Kepler's peers didn't understand the profound importance of his work. The full significance of the two planetary laws did not become apparent until years later, when Newton used them to formulate his theory of universal gravitation. Until then, Kepler's system was little more than an aesthetic monstrosity. Even Kepler was dismayed by the loss of uniform circular motion – he disliked the idea of elliptical orbits as much as everyone else.
Although no one fully understood the ramifications of his work, it was accorded respect by the scientific community. Kepler was in a far different position than he'd been in ten years before. By the time the Astronomia Nova was published, Kepler was one of the most famous astronomers in Europe, primarily due to his title as the Imperial Mathematicus. He was also well respected for the other scientific research he'd done while working on the orbit of Mars, including the impressive work he'd done in the field of optics. In 1604, a new star had appeared in the sky and Kepler had proved that it was indeed a new star, not merely an atmospheric phenomena. As an indication of his newfound fame, the star became known as Kepler's Nova. While few recognized the Astronomia Nova for the landmark work that it was, the book only added to his prestige. Kepler's star was on the rise.
As one of Europe's top astronomical experts, Kepler was expected to have an opinion on any news in the field. The scientific community was eager to hear he had to say in 1610, when an Italian scientist named Galileo Galilei announced he had made a startling discovery. Galileo, who was a few years older than Kepler, was the first major astronomer to make use of a brand new tool for observing the stars: the telescope. In 1610, Galileo published his short book Sidereus Nuncius, or A Message From the Stars. He announced that he had discovered four new celestial bodies: the moons of Jupiter.
Kepler and Galileo had corresponded briefly in earlier years; in 1597, Galileo had complemented Kepler on his support of the Copernican system. In a later, Galileo admitted that he too supported it, but was hesitant to make that fact public. Kepler responded with a letter urging Galileo to get over his fears – a letter which Galileo may have taken as a personal affront, as he never responded.
Kepler and Galileo had not spoken for twelve years, but when the report of Galileo's observations came out, Kepler supported them. Kepler was the only one; the rest of the scientific community was quick to decry Galileo's discoveries. When Kepler requested that Galileo send him a telescope so that he could make an independent confirmation of Galileo's discoveries, Galileo ignored him. Frustrated and a bit embarrassed that he had staked his scientific reputation on a discovery of which he had no evidence, Kepler persevered. Finally, he was able to borrow the telescope of a nearby nobleman and publish Observation – Report on Jupiter's Four Wandering Satellites. It was the first independent confirmation of the existence of the moons of Jupiter.
But if Kepler's professional life was finally soaring, his personal life was falling apart. In 1611, Kepler's wife and favorite child died of the Hungarian Fever. Adding to this misery, the situation in Prague was becoming increasingly unstable. In 1611, Kepler's patron, Rudolph II, went insane and was forced to give up the throne; he died in January of 1612. While Kepler continued to serve as the Imperial Mathematicus, his new patron was not nearly as interested in astronomy as Rudolph II had been. The new emperor didn't care whether his imperial astronomer was by his side or across the country, so Kepler was free to leave Prague. The city was being torn apart by civil war, and Kepler decided to leave immediately.
He moved to Linz, a small town in Upper Austria, where he served as Provincial Mathematicus for fourteen years. The position was less glamorous than Kepler was used to, but it afforded him more freedom, as he was no longer at the beck and call of the emperor. The next year, Kepler married his second wife, the 24-year- old Susanna Pettinger. Kepler had had a difficult time convincing his first wife that he was worthy of marriage; this time, he had eleven different women to choose from, all eager to have his hand. Kepler and Susanna had eleven children and, since he rarely mentioned her or her shortcomings in later life, seem to have lived happily.
Kepler had only a short time to enjoy his marital bliss. It wasn't long before yet another crisis interceded in his life. In 1615, he was forced to rush to his mother's side in the town of Leonberg, to save her from being burned at the stake. The townspeople were convinced that Katherine Kepler was a witch.
Although the seventeenth century was a time of modernization and scientific progress for Europe, it was also the peak of the European witch-hunts. Weil-der- Stadt, Kepler's hometown, had burned thirty-eight supposed witches in the years between 1615 and 1629. Katherine's new home Leonberg was no more tolerant. It took Kepler five years of arguments and trials to save his mother's life. In 1620, it was decreed that Katherine be interrogated under threat of torture. When the old woman refused to confess anything, even in that precarious situation, the powers that be finally decided that she must be innocent. She was released, but was unable to go home, as the townspeople threatened to lynch her. She died six months later.
Incredible as it seems, Kepler had remained hard at work throughout this period of political crises and personal torment. In 1618, he published his newest discoveries in his last major work, Harmonice Mundi, or Harmony of the World. In a footnote to the Harmonice Mundi, Kepler implied that he could block out, but not ignore, the troubles around him: "The Earth sings Mi-Fa-Mi, so we can gather even from this that Misery and Famine reign on our habitat."