Sidereus Nuncius, or The Sidereal Messenger

Van Helden divides his book into three sections: First, he gives a well researched, well footnoted, introduction to Galieo and his times. We learn about the invention of the telescope (then called the "Spyglass")- an exceptionally crude instrument by even the most modest of today's standards. Van Helden tells his story with abundant quotes from the writings of Galileo's contemporaries. Amongst other things, we learn that another astonomer, Thomas Harriot, may have observed the moon with a telescope somewhat before Galileo, but that his observations, through an inferior instrument, did not reveal much more than could be seen with the naked eye. We learn about the then dominant view of the univserse, the geocentric "Aristotelean" model and the arguments given in favor of it. We also learn about Galileo himself. The publication of the "Starry Messenger," was, it seems, a bit of a rush job, as a financially strapped Galileo wanted priority for his discoveries and the position and money that he though would go with it.

We also learn that while Galileo didn't invent the telescope (or SpyGlass) he greatly improved it from an almost totally useless instrument, to a useful, merely wretched, one (again, by today's standards.)

The middle section is Galileo's "Starry Messenger" itself. The text is brief and only strays a bit from a simple recounting of his observations to explain such things as his deduction of the height of the moons' mountains. Galileo wrote with a wide and not necessarily scientific audience in mind and he took their preconceptions into account when cobbling together his "message". This makes his thought process easy to follow. (Van Helden's translation uses apropriately contemporary English.) It's a delight to read about Galileo's observations and follow his careful (though sometimes incorrect) reasoning about what he has seen. There are delighful reproductions of Galileo's illustrations of the moon, stars, and Jupiter's satellites.

Armed with the knowledge and sense of the times that Van Helden has given us, Galileo's discoveries feel as revolutionary as they were. (Quite a feat, given our current view of the universe.) Having learned that the Aristotelians thought of the universe as somehow different, more perfect, than the "corrupted" terrestrial world, Galileo's observations of the moon take on great significance. Galileo wonders in amazement at the multitudes of stars his telescope reveals and gives a few sample drawings of some "nebular" regions of the Milky Way- which he discovers are mere assemblages of stars too faint to make out individually, but which cumulatively present to the eye a cottony appearance.

The least readable portion of Galileo's writing is also the most significant and carefully presented: his discovery and observations of the "Medician" moons- as he dubbed them, we now refer to them as the four "Galilean" moons. Galileo makes it clear that he, early in his observations of the planet Jupiter, sensed the three (later four) "stars" that he had discovered whirling about Jupiter were significant. He proceeds to carefully, and monotonously, document several weeks of observations of what he comes to consider planets. That he chose to do this in such a thorough way, however, is telling. Despite his desire to publish early and claim priority, Galileo wanted to assure his readers that what he was seeing was real.

Throughout the text, the translator provides footnotes explaining some of Galileo's mistakes, later changes of thought, and the context of a given argument. I came away from the text knowing exactly what Galileo was attempting to convey, and the few places where he went wrong (for instance, in surmising that the moon had a thick atmosphere).

The third section is similar to the first and covers the immedate reaction to the publication of the Sidereus Nuncius- which Galileo sent to as many heads of state as he could, often sending a spyglass along with the text so that observations could be repeated. Van Helden outlines many of the objections to Galieo's claim that he had discovered the moon to be rough and Jupiter to be surrounded by satellites of its own. The most significant of these objections was grounded, once again, in the Aristotelian logic of the day which claimed that one could learn all there was to learn about the world with the unaided senses. In other words, people didn't believe that the telescope (the first instrument to extend human senses beyond their natural talents) could be trusted to present reality.

Van Helden only briefly hints at Galileo's subsequent trial and trouble with the Church. This seems apropriate, however, considering that, at the time of its publication, some of Galileo's most ardent supporters were not other "natural philosophers" or "mathmeticians"- who, Van Helden demonstrates, were sometimes jealous and harshly critical- but some members of the Church- his sponsors.

All in all, this is a wonderful introduction to the times and discoveries of Galileo. It's a great book to read for those who enjoyed Galileo's Daughter and other biographies one of the world's first true scientists. That the words "Starry Messenger" do not appear in the title might throw a few potential readers off its trail in their search for a good translation, and this is a shame- let's hope that Amazon's new search engine brings this one up from the depths.


Wonderful Bit of Astronomical History   April 4, 2000
David Wilkins (Philadelphia, PA USA)
9 out of 9 found this review helpful

This is Galileo's report of his first discoveries with the telescope, especially his drawings of the moon and obervations of Jupiter's satellites. To read Galileo's ideas, methods, and results first hand gives an idea of his brilliance and attention to detail. This book was crucial in the development of the Copernican revolution. It is exciting to read, and not at all difficult.


A Starry Message in Galileo's Own Words   November 15, 2000
Sandra Tragesser (Houston, TX USA)
8 out of 9 found this review helpful

This new translation, with introduction, conclusion, and notes, by famed author Albert Van Helden is a wonderful reading of Galileo Galilei's timeless classic, Sidereus Nuncius. For all who are astronomy fans, Van Helden, Professor of History at Rice University, gives readers a glimpse of the man, Galileo, and his earth-shattering findings. In his book,Sidereus Nuncius, or the Sidereal Messenger, Galileo describes his reinvention of the refracting telescope and his subsequent astronomical discoveries. Never before has a scientific instrument had a more dramatic impact than that of Galileo's telescope. It not only advanced scientific knowledge, but affected personal philosophy and religion by upsetting the traditional belief of the Earth as the center of the universe. Galileo's work challenged the geocentric cosmology that had been accepted since the days of Aristotle. If Galileo's discoveries and carefully documented observations were true, people had to accept the fact that the Earth was not at the center of the universe. This was very difficult for people in the 17th century to accept because it went against long held beliefs.. Add Galileo's analysis of an imperfect moon and people were force to reevaluate history,science, and their personal religions. Galileo opened the door to the truth about our heliocentric universe; however, few people of his day were prepared to accept it. Van Helden's translation, based on the original 1610 Latin text, is a wonderful book for all those who enjoy gazing into the heavens on a clear, star-filled night in wonder. Galileo Galilei did the same. Everyone will enjoy reading Sidereus Nuncius, as Galileo's voice echoes down the centuries and brings his amazing discoveries to life.


Significant Work   February 25, 2002
Mark Garrett (Charlotte, NC USA)
6 out of 7 found this review helpful

This book will help you understand just how much Galileo affected and reflected the science of the time and even the science of today. I had the privilage of taking Prof. Van Helden's courses at Rice U. and they were some of the most informational and facinating courses I took. He is now emeritus, but hopefully that means we can look forward to more excellent translations and commentary in the years to come.