AkN Science: BOOK OF THE MONTH: MAY 2012

Title : Chasing Venus:
The Race to Measure the Heavens
Authors : Andrea Wulf
Publisher : William Heinemann
Pages : 336
ISBN : 10: 0307700178
Price : $16.95

On June 5 or 6, depending on the time zone, millions of people around the globe will watch Venus glide across the sun in a rare celestial event that won't happen again until 2117.The Transit of Venus was the key to unlocking the distance between Earth and the sun and by extension, the size of our solar system. In a fitting homage to these strenuous efforts of 18th-century astronomers,the Indian born British writer British Andrea Wulf has written an absorbing account of their expeditions to do so in 1761 and 1769.

On June 6, 1761, the world paused to observe a momentous occasion: the first transit of Venus between the earth and the sun in more than a century. Through that observation, astronomers could calculate the size of the solar system--but only if the transit could be viewed at the same time from many locations. Overcoming incredible odds and political strife, astronomers from Britain, France, Russia, Germany, Sweden, and the American colonies set up observatories in remote corners of the world only to have their efforts thwarted by unpredictable weather and warring armies.

She begins the story with legendary astronomer Edmond Halley.In 1663 James Gregory suggested that observations of a transit of the planet Mercury could be used to calculate the Solar Parallax. Aware of this a young Edmund Halley made observations of such a transit in 1676 from St Helena, but was disappointed to find that the resulting calculation of the Solar Parallax at 45" was accurate. He proposed that more accurate calculations could be made during the next transit which was due until 1761. But Halley died in 1742.

On the basis of his observation of the transit of Venus of 1761 from the Petersburg Observatory, Mikhail Lomonosov predicted the existence of an atmosphere on Venus. Lomonosov detected the refraction of solar rays while observing the transit and inferred that only refraction through an atmosphere could explain the appearance of a light ring around the part of Venus that had not yet come into contact with the Sun's disk during the initial phase of transit.

Andrea Wulf was born in India and moved to Germany as a child. She lives in London, where she trained as a design historian at the Royal College of Art. She is the author of The Brother Gardeners, long-listed for the Samuel Johnson Prize in 2008 and winner of the American Horticultural Society 2010 Book Award, and of Founding Gardeners; she is the coauthor (with Emma Gieben-Gamal) of This Other Eden: Seven Great Gardens and 300 Years of English History.

Author Website: http://www.andreawulf.com