Chasing Venus

Starred review from April 1, 2012
In the late 18th century, European astronomers scurried about the globe measuring the transit of Venus, hoping, at last, to learn the size of our universe. Until this busy narrative, Wulf had turned her eyes more earthward with three previous outings about gardens (The Founding Gardeners: The Revolutionary Generation, Nature, and the Shaping of the American Nation, 2011, etc.). Here she glides easily into the heavens, where she clearly explains how Venus' transit across the sun, which occurs every 105 years (and each time does so twice, at eight-year intervals--one will occur in June 2012), gave Enlightenment astronomers a chance to figure out such things as the distance between the earth and the sun. Their 1769 calculation--transit-derived--was quite close. The author follows the two international attempts, in 1761 and 1769, to accomplish the measurements from various global viewing points, describing in grim detail the vast difficulties of travel and communication, the geopolitical complications (wars didn't help) and the various personalities of potentates and scientists that characterized the endeavor. The 1761 transit occurred before everyone were sufficiently ready, and the measurements were disappointing; 1769 was better--though poor Guillaume Le Gentil of France, who'd spent nine years devoted to the projects, saw only clouds at his observatory in Pondicherry, India. Worse, Jean-Baptiste Chappe d'Auteroche died of typhus only days after his successful recordings. The author notes the imprecision of the instruments, the difficulties of determining precisely when the dark spot of Venus began and ended its journey across the sun's yellow wafer and the arduous treks Enlightenment men (yes, all men) undertook to Lapland, Tahiti, Hudson Bay and Baja. More than 100 pages of back matter reveal the sturdy research undergirding the lively narrative. Like a nonfiction National Treasure with myriads of Nicholas Cages darting around--in a good way. Enlightening Enlightenment fare.

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June 1, 2012

During Venus's transit, observers can see the planet as a small black dot against the face of the sun. The transit is a rare event: while the last one occurred in June 2004 and the next will occur in June of this year, Venus will not appear again between Earth and the Sun until December 2117. Like Mark Anderson's The Day the World Discovered the Sun (reviewed above), Wulf's (Founding Gardeners: The Revolutionary Generation, Nature, and the Shaping of the American Nation) book is concerned with Venus's 1761 and 1769 transits, when the international science community dispatched a remarkable set of expeditions to remote parts of the world to observe and measure the planet's passages across the sun. Their primary objective was to use newly acquired observational data to improve knowledge of the distance between Earth and the Sun and the solar system's dimensions. Many of the traveling scientists underwent great travails, and several died. VERDICT Wulf well describes the scientific problems and physical trials these astronomers had to solve and endure. Recommended for all readers interested in the history of science.--Jack W. Weigel, Ann Arbor, MI

Copyright 2012 Library Journal, LLC Used with permission.

May 1, 2012
A rare, once-in-a-lifetime celestial event, a transit of Venus across the solar disk enables astronomers to measure the distance between the earth and the sun. The trigonometry of the measurement, however, requires observers to be separated by thousands of miles, which in 1761 and 1769, when transits were predicted by Edmund Halley, necessitated months and years of arduous travel to get into position. The voyages and their inevitable misadventures inspire Wulf's enthusiastic account, which opens with the international ringmaster for 1761, French astronomer Joseph-Nicolas Delisle. His pleas successfully instigated several expeditions that faced, in addition to the hazards of the sea and atrocious roads, those of the Seven Years' War. Whether enemy warships or clouds, mishaps so interfered with seeing Venus that 1761 was a dud. Motivated not to squander 1769, scientists again spread across the globe. Wulf details their finances, instruments, journeys (which cost several astronomers their lives), and the observations that triumphantly revealed the true dimensions of the solar system. With the next transit predicted for June 6, 2012, Wulf's well-handled history arrives in a timely manner.(Reprinted with permission of Booklist, copyright 2012, American Library Association.)