William Sheehan – författare

Written by William Sheehan, a noted historian of astronomy, and Christopher J. Conselice, a professional astronomer specializing in galaxies in the early universe, this book tells the story of how astronomers have pieced together what is known about the vast and complicated systems of stars and dust known as galaxies.

The first galaxies appeared as violently disturbed exotic objects when the Universe was only a few 100 million years old.  From that tortured beginning, they have evolved though processes of accretion, merging and star formation into the majestic spirals and massive ellipticals that dominate our local part of the Universe. This of course includes the Milky Way, to which the Sun and Solar System belong; it is our galactic home, and the only galaxy we will ever know from the inside.  Sheehan and Conselice show how astronomers’ understanding has grown from the early catalogs of Charles Messier and William Herschel; developed through the pioneeringefforts of astronomers like E.E. Barnard, V.M. Slipher, Henrietta Leavitt, Edwin Hubble and W.W. Morgan; and finally is reaching fruition in cutting-edge research with state-of-the-art instruments such as the Hubble Space Telescope that can see back to nearly the beginning of the Universe.  By combining archival research that reveals fascinating details about the personalities, rivalries and insights of the astronomers who created extragalactic astronomy with the latest data gleaned from a host of observa

Much of what is known about the universe came from the study of celestial shadows. This book looks in detail at the way eclipses and other celestial shadows have given us amazing insights into the nature of the objects in our solar system and how they are even helping us discover and analyze planets that orbit stars other than our Sun. A variety of eclipses, transits, and occultations of the mooons of Jupiter and Saturn, Pluto and its satellite Charon, asteroids and stars have helped astronomers to work out their dimensions, structures, and shapes - even the existence of atmospheres and structures of exoplanets.

Long before Columbus set out to reach the Far East by sailing West, the curved shadow of the Earth on the Moon during a lunar eclipse revealed that we inhabit a round world, a globe. More recently, comparisons of the sunlit and Earthlit parts of the Moon have been used to determine changes in the Earth''s brightness as a way of monitoring possible effects in cloud coverage which may be related to global warming. Shadows were used by the Greek mathematician Eratosthenes to work out the first estimate of the circumference of the Earth, by Galileo to measure the heights of the lunar mountains and by eighteenth century astronomers to determine the scale of the Solar System itself.

Some of the rarest and most wonderful shadows of all are those cast onto Earth by the lovely "Evening Star" Venus as it goes between the Earth and the Sun. These majestic transits

Using the "Parallel Lives" approach adopted by the Greek biographer Plutarch, noted historian of astronomy William Sheehan contrasts the lives and research careers of two famous astronomers, Percival Lowell and Edward Emerson Barnard.  Drawing on vast archival materials and hitherto unpublished source materials, Sheehan documents in detail the contributions of these two late 19th and early 20th astronomers. 

Living at a time when controversies about Mars peaked, when great observatories were being built, and when research increasingly turned away from the Solar System toward the stellar and extra-galactic universe, these observers made spectacular contributions to astronomy.  Their work still inspires, and continues in Perseverance rover''s explorations of the surface of Mars carrying forward Lowell''s dream of showing that Mars may once have been "the abode of life," and in Barnard''s pioneering wide-angle photographs of the Milky Way which first showed the sweep, majesty and complexity of the Galaxy.

  The work of decades of research and writing, Sheehan has produced what is likely to become the definitive work on these two great astronomers.

 "Parallel Lives marks an important contribution to the history of astronomy. The book is masterful and inventive. William Sheehan could hardly have chosen two more compelling—or contrasting—personalities to analyze in this fascinating dual biography."

   - David Baron, author of American Eclipse and The Martians, and former Chair in Astrobiology at the Library of Congress.

"Sheehan has united scientific acumen, detailed historical research, penetrating insight into character, and narrative virtuosity—and adapted it all to an ancient Greek model—a remarkable achievement!"

  - Michael Armstrong, Assoc. Prof. Emeritus of Classics, Hobart and William Smith Colleges, Geneva NY

   William Sheehan''s many books include the authoritative biography The Immortal Fire Within: The Life and Work of Edward Emerson Barnard and (with Jim Bell) Discovering Mars: A History of Observation and Exploration of the Red Planet, which has been called the "gold standard of books on Mars" (Michio Kaku).