Starry Messenger : Galileo’s Sidereus Nunceus

The Starry Messenger : Galileo’s Sidereus Nunceus ( First Hand observations of the sky through a telescope)


Galileo’s Sidereus Nunceus is also known as the ‘Starry Messenger’. He wrote it in English in the year 1610. The book mainly contains Galileo’s observations of the stellar bodies made from his newly invented telescope. The book was important mainly for it was the first description of the telescopic observation of stellar bodies ever published. Most important are the lively accounts of the moon and Galileo’s observations of the Jupiter and its four satellites. Actually, Sidereus Nunceus is more in the form of a Latin treatise that deals with Galileo’s observation of Jupiter’s moons.  He dedicated his work to Cosimo de Medici and even named the moon she had observed after the name of the Medici family as the Medician stars. Galileo’s observations were marvellous and the entire philosopher and scientist community marveled at his description of the sky in Sidereus Nunceus. The book came to be known as the wonder of Europe. For the first time when Galileo observed the moons, he thought they were stars. However, as he observed them carefully he could mark their motion relative to Jupiter that made him infer they were its moons.

Apart from taking notes of his observation, Galileo made careful drawings of his observations. His book contains at least seventy different drawings of the moon and other various constellations as well as the Medicean stars. The response to Suidereus Nunceus was varied. While it struck many with awe, others approached it with disbelief and hostility. Several of the astronomers had responded enthusiastically to his work and appreciated his efforts. However, Aristotle’s and Ptolemy’s ideas of an unchanging universe came to clash with the new discoveries he had made. The Roman Catholic Church had relied on the ideas of Aristotle and Ptolemy. As a result, Galilelo’s work was considered irreligious and blasphemous. The system that Galileo had discovered was far more chaotic than people knew it as. However, his observations also brought a sea change in the way people saw the universe and the earth’s place in it.


Galileo registered several important achievements in his life. He was known not only for being a great astronomer but also for having the courage to challenge the accepted truths and for having given the world a new view of the universe and the space. His discoveries were exciting but also deeply unsettling for many who had accepted the view of an unchanging universe. Soon, after he had written his Sidereus Nunceus in 1610, he was appointed the first mathematician of the university of Pisa and the First mathematician and Philosopher to the Grand Duke. His other important contributions include ground breaking research in physics as well as the discovery of the law of inertia. In his works, Galileo produced evidence to show that neither the earth, nor the other planets were still and that they were continuously circling the sun. The evidence that his telescope provided with made him strongly advocate the Copernican theory. It was 1616 when the church gave him the first formal warning regarding his ideas being in clash with the doctrine of the Church. In the later part of his life, Galileo was made to suffer bitterly on account if his views of the universe.

After having received the Church’s warning, Galileo did not publish anything regarding his theories for a decade. In 1632, came his “Dialogue Concerning the Two Chief World Systems” in which he argued in the favour of the Copernican theory. The result was that he was tried and forced to renounce his views. Near the end of his life, he was forced to retire to the hilltop village of Arcetri where he lived in a small villa under house arrest. The clash between his views and that of the Church brought him enormous suffering. Still, he was one of the most brilliant minds of his age and his fame spread throughout Europe as his books were published. People pitied him for how he suffered at the hands of the Church. His death took place in 1642 in Arcetri after he suffered with fever and heart palpitations.  Galileo won but after his death and his books came to widely admired. In 1758, The Church had lifted the ban on most of his works that argued in favour of the Copernican theory.

Written by Abhijeet Pratap

Abhijeet has been blogging on educational topics and business research since 2016. He graduated with a Hons. in English literature from BRABU and an MBA from the Asia-Pacific Institute of Management, New Delhi. He likes to blog and share his knowledge and research in business management, marketing, literature and other areas with his readers.

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