Rating: 
Summary: Delightful little book
Review: A delightful short book about an astronomical event both dynamic and rare, and one that has an important place in the history of science. Venus is the closest planet to earth, and having an inferior orbit (closer to the sun than us), can occasionally be seen to cross the face of the sun - a transit. Such events can be observed with the naked eye (appropriately filtered) but are relatively rare, occurring in pairs separated by about 8 years, 100 years apart. Only five times in recorded history have Venus transits been observed, and Maor tells the story of each encounter painted in lively narrative against the historical backdrop of the times. From theorist Kepler, whose accurate calculations of the orbits of the planets first permitted accurate prediction, to observers Gassendi and Horrocks in the 17th century, Maor intersperses the story with well written nontechnical explanations of the celestial mechanics that lie behind the transit phenomenon, including the best explanation I have ever read of the reason behind the curious pairing of two transits just 8 years apart, with each pair separated by 100 years or more.The historical importance comes due to the fact that as astronomers were slowly unraveling the mysteries of the solar system, the absolute distance scale remained elusive. Kepler's 3rd law allowed scientists to compute the relative distances of the planets from the sun, but absolute distances couldn't be obtained unless one knew the exact distance from the sun to the earth. In 1677, Edmund Halley observed a transit of Mercury, and realized that a transit event could serve as an excellent opportunity to obtain measurements of the transiting planet's parallax, from which could be calculated the distance of the transiting body. Then, using Kepler's 3rd law, the distances of all other planets - including the earth - could be calculated. Halley worked on the problem for almost 40 years, and in 1716 published a detailed plan for using the next transit of Venus to determine the size of the solar system. Already 60 when he published his plan, Halley knew he would be long dead before the next transit in 1761, but his scientific stature and eloquent appeal was all that was necessary - when the time came, the scientific world was ready (Halley's posthumous reputation was further enhanced when the periodic comet that now bears his name reappeared in 1758, just as he had predicted). Alas, Venus transits proved not to be the answer to the scale of the solar system (exact timing of transit events proved unreliable due to Venus's thick atmosphere), but the stories of the explorers who traveled to the corners of the earth in 1761, 1769, 1874 and 1882 are worth the price of the book. Maor concludes by pointing out that the upcoming event in June of 2004 will the only the sixth opportunity in recorded history to observe such an event, and while scientists are no longer watching for the same reasons as two centuries ago, the event will have enormous popular appeal. Maor's book is wonderfully written, and will be of interest to amateur astronomers as well as those with an interest in the history of science.
Rating:
Summary: Delightful little book
Review: A delightful short book about an astronomical event both dynamic and rare, and one that has an important place in the history of science. Venus is the closest planet to earth, and having an inferior orbit (closer to the sun than us), can occasionally be seen to cross the face of the sun - a transit. Such events can be observed with the naked eye (appropriately filtered) but are relatively rare, occurring in pairs separated by about 8 years, 100 years apart. Only five times in recorded history have Venus transits been observed, and Maor tells the story of each encounter painted in lively narrative against the historical backdrop of the times. From theorist Kepler, whose accurate calculations of the orbits of the planets first permitted accurate prediction, to observers Gassendi and Horrocks in the 17th century, Maor intersperses the story with well written nontechnical explanations of the celestial mechanics that lie behind the transit phenomenon, including the best explanation I have ever read of the reason behind the curious pairing of two transits just 8 years apart, with each pair separated by 100 years or more. The historical importance comes due to the fact that as astronomers were slowly unraveling the mysteries of the solar system, the absolute distance scale remained elusive. Kepler's 3rd law allowed scientists to compute the relative distances of the planets from the sun, but absolute distances couldn't be obtained unless one knew the exact distance from the sun to the earth. In 1677, Edmund Halley observed a transit of Mercury, and realized that a transit event could serve as an excellent opportunity to obtain measurements of the transiting planet's parallax, from which could be calculated the distance of the transiting body. Then, using Kepler's 3rd law, the distances of all other planets - including the earth - could be calculated. Halley worked on the problem for almost 40 years, and in 1716 published a detailed plan for using the next transit of Venus to determine the size of the solar system. Already 60 when he published his plan, Halley knew he would be long dead before the next transit in 1761, but his scientific stature and eloquent appeal was all that was necessary - when the time came, the scientific world was ready (Halley's posthumous reputation was further enhanced when the periodic comet that now bears his name reappeared in 1758, just as he had predicted). Alas, Venus transits proved not to be the answer to the scale of the solar system (exact timing of transit events proved unreliable due to Venus's thick atmosphere), but the stories of the explorers who traveled to the corners of the earth in 1761, 1769, 1874 and 1882 are worth the price of the book. Maor concludes by pointing out that the upcoming event in June of 2004 will the only the sixth opportunity in recorded history to observe such an event, and while scientists are no longer watching for the same reasons as two centuries ago, the event will have enormous popular appeal. Maor's book is wonderfully written, and will be of interest to amateur astronomers as well as those with an interest in the history of science.
Rating:
Summary: A syzygy for everyone
Review: A transit of Venus is a kind of solar eclipse in which the planet Venus, rather than our moon, crosses in front of the Sun. A century-long interval between transits makes the normal kind of solar eclipse seem like a frequent event. The transits occur in pairs separated by eight years, with over one hundred-year separations between the pairs. The last transit of Venus was in 1882. However, we can look forward to the transits of 2004 and 2012. By traveling thousands of miles, I have been able to place myself in the path of the shadow for six total and two annular solar eclipses. With careful planning, and some last minute scurrying to avoid clouds, my success rate for viewing of the critical event is seven of eight. How ironic that today I was able to walk into my own back yard to view a partial solar eclipse under a clear cloudless sky. By contrast with total solar eclipses, which may be viewed only within a narrow corridor, a transit of Venus may be viewed from any place on the Earth that faces the Sun during the event. Thus, simultaneous observations may be made from distant locations. The author tells the story of the pursuit of transits of Venus by scientists whose aim was to establish a precision measurement of the distance between the Earth and the Sun. It is a great adventure story. There are the usual disasters: there are wars; ships are intercepted; natives run off with the instruments; and there are clouds. Finally, an unexpected optical effect, the "black drop", appears. In the end science triumphs, although not as expected. We no longer need to measure the transits of Venus to establish the astronomical unit. However, our ability to calculate and predict precise locations and times for the occurrence of such events as eclipses and transits is a confirmation of the success of our formulation of mechanics and an affirmation of the scientific method. This work is primarily a history with the basic information on the details of the transit of 2004 and very little on the transit of 2012. The reader will have to go to the web for more. However, the eastern Mediterranean looks promising for 2004, while the transit of 2012 should provide an excuse for a trip to Hawaii.
Rating:
Summary: A syzygy for everyone
Review: A transit of Venus is a kind of solar eclipse in which the planet Venus, rather than our moon, crosses in front of the Sun. A century-long interval between transits makes the normal kind of solar eclipse seem like a frequent event. The transits occur in pairs separated by eight years, with over one hundred-year separations between the pairs. The last transit of Venus was in 1882. However, we can look forward to the transits of 2004 and 2012. By traveling thousands of miles, I have been able to place myself in the path of the shadow for six total and two annular solar eclipses. With careful planning, and some last minute scurrying to avoid clouds, my success rate for viewing of the critical event is seven of eight. How ironic that today I was able to walk into my own back yard to view a partial solar eclipse under a clear cloudless sky. By contrast with total solar eclipses, which may be viewed only within a narrow corridor, a transit of Venus may be viewed from any place on the Earth that faces the Sun during the event. Thus, simultaneous observations may be made from distant locations. The author tells the story of the pursuit of transits of Venus by scientists whose aim was to establish a precision measurement of the distance between the Earth and the Sun. It is a great adventure story. There are the usual disasters: there are wars; ships are intercepted; natives run off with the instruments; and there are clouds. Finally, an unexpected optical effect, the "black drop", appears. In the end science triumphs, although not as expected. We no longer need to measure the transits of Venus to establish the astronomical unit. However, our ability to calculate and predict precise locations and times for the occurrence of such events as eclipses and transits is a confirmation of the success of our formulation of mechanics and an affirmation of the scientific method. This work is primarily a history with the basic information on the details of the transit of 2004 and very little on the transit of 2012. The reader will have to go to the web for more. However, the eastern Mediterranean looks promising for 2004, while the transit of 2012 should provide an excuse for a trip to Hawaii.
Rating:
Summary: beautiful melding of science and narrative
Review: As he did with E and Trigonometric Delights, Maor combines technical expertise with a sure sense of narrative to tell the story (or rather the many different stories) of the transits of Venus. Gives a different meaning to the slogan "Four More Years."
Rating:
Summary: Maor does it again!
Review: Even if all you know about Venus is that "Men are from Mars, women are from Venus", you will still enjoy this book. Maor is a both a great writer and a mathematician, and he combines clear explanations with great narrative. But anybody who's read any of his other books knows this already!
Rating: 
Summary: Incomplete history, muddled science
Review: I have read a few of Eli Maor's books. They are not great masterpieces, but they fill a niche, providing all the information I wanted and more. This one was less satisfying. This became clear on page 58, where he states that Venus crosses the ecliptic on December 8 and June 7, and transits can occur only when Earth reaches the same node at the same time. Perhaps he is using the Venusian calendar, but in our calendar Earth will be there in December and June while the location of Venus will vary. I bought this book because the transit of Venus in 1874 was significant in the history of Campbell Island (French expedition)and Auckland Island (German expedition) in the sub-Antarctic region. There were also Americans on Kerguelen and French on St. Paul Island, and probably others. Maor mentions only the British and German expeditions to Kerguelen, where the Brits released rabbits that devastated the native vegetation. The scale of the effort is not apparent from his tale. My second objective was to learn what other mmethods were used to measure the astronomical unit when the transit of Venus proved inadequate. Maor mentions only that a measurement of the parallaz of Mars was used, but gives no hint how. Apparently there were other methods before WWII, but they are not in this book. Too much space is devoted to failures and speculations, pleasant stories properly used as side dishes, too little to the main course.
Rating:
Summary: Incomplete history, muddled science
Review: I have read a few of Eli Maor's books. They are not great masterpieces, but they fill a niche, providing all the information I wanted and more. This one was less satisfying. This became clear on page 58, where he states that Venus crosses the ecliptic on December 8 and June 7, and transits can occur only when Earth reaches the same node at the same time. Perhaps he is using the Venusian calendar, but in our calendar Earth will be there in December and June while the location of Venus will vary. I bought this book because the transit of Venus in 1874 was significant in the history of Campbell Island (French expedition)and Auckland Island (German expedition) in the sub-Antarctic region. There were also Americans on Kerguelen and French on St. Paul Island, and probably others. Maor mentions only the British and German expeditions to Kerguelen, where the Brits released rabbits that devastated the native vegetation. The scale of the effort is not apparent from his tale. My second objective was to learn what other mmethods were used to measure the astronomical unit when the transit of Venus proved inadequate. Maor mentions only that a measurement of the parallaz of Mars was used, but gives no hint how. Apparently there were other methods before WWII, but they are not in this book. Too much space is devoted to failures and speculations, pleasant stories properly used as side dishes, too little to the main course.
Rating: 
Summary: Venus in Transit doesn't cast a long shadow
Review: I read e: The Story of a Number and Trigonometric Delights from Eli Maor and found both to be well written and enjoyable. With the transit of Venus approaching, the previous experience with Eli Maor brought me to his latest book. The writing style is the same, clear, fluent, but Venus in Transit is at a different level, more superficial than any of the other two books. And a couple of statements make you wonder. On page 58 "...Venus reaches its ascending node around December 8, and its descending node around June 7, so a transit can happen only around these dates. But for a transit actually to occur, Earth, too, must cross the line of the nodes on these dates." There is an inversion here, for Earth reaches the line of nodes at the given dates, while Venus is usually elsewhere in its orbit at these dates as already pointed by another reviewer. And then on page 20 when describing Galileo's observations of the phases of Venus as the first solid proof for the heliocentric system, the author states: " Venus showed phases like the moon - a narrow crescent at the time, a gibbous shape at another, and occasionally a nearly full disk. Here was solid proof that Venus moved around the sun; for had it moved around d the earth instead, it would have shown a full disk at each opposition, when it was directly opposite to the sun [sic]." This is surprising. Venus is never at opposition with the Sun as the ancients new very well by observation. The epicycles and deferents in the geocentric system of Ptolemy had their sizes and speeds carefully adjusted to account for the maximum elongation of 47 degrees or so along the ecliptic between the Sun and Venus. And although the geocentric system could not account for a full disk because in that system Venus was always between the Earth and the Sun, the alternative system proposed by Tycho Brahe could. These two inconsistencies suggest that Eli Maor is not exactly at home when discussing planetary astronomy and perhaps this is the source of the different levels between this book and the other two dealing with mathematics.
Rating:
Summary: Interesting, simple astronomy
Review: This book traces the history of the Venus transit, which is when Venus transits between the sun and earth, thus casting the planet's shadow on the sun. Happening only every 121 years, Maor explores the lives of the many scientists that studied the Venus transit in order to come up with an estimation of the astral unit (the distance between the sun and earth...about 93 million miles), including Galileo, Hell, Copernicus, Kepler, Brahe, and more. The book is very good, and one is left marveling at astronomy and eager to the coming of the transit, but Maor is very extensive in his history at times.
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