Galactic Encounters: Our Majestic and Evolving Star-System, From the Big Bang to Time's End
William Sheehan
Language: English
Pages: 385
ISBN: 0387853464
Format: PDF / Kindle (mobi) / ePub
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 pioneering efforts 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
tions, the authors provide a view of galaxies – and their place in our understanding of the Universe – as they have never been seen before.
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henceforth he allowed the existence of truly nebulous matter—a “shining fluid” or “fire-mist”—into the heart of his cosmogony. During these years, visitors continued to stream to Observatory House. One of the most famous was the composer, Joseph Haydn, who on his visit to England in 1791 came to Windsor to meet George III and paid a visit to Slough to look through Herschel’s telescope. He later claimed that the experience helped him to compose his celebrated oratorio Creation, which premiered at
such as M33 and M101, do show starlike objects in their outer parts, which appear in better instruments as nebulous knots of glowing gaseous matter (now known as HII regions). These are much brighter than individual stars. Of course, we shall say more to say about all this later, but for now let’s stay with Rosse and Robinson. In these observers’ first remarks on M51, no comment was made on what was to be its most notable feature—its spiral structure. When, and under what circumstances, was the
early as 1857, G.P. Bond obtained a wet-collodion plate of the double star Mizar and Alcor, in the handle of the Big Dipper, and confidently predicted the future application of photography in astronomy on a magnificent scale. Dying tragically young, he did not live to see it. Even wet-collodion plates were only to capture images of the brighter celestial objects, such as the Sun (photographed on every clear day from the King’s Observatory at Kew between 1858 and 1872, when the program was
were arranged outside one of the windows; a large induction coil stood mounted on a stand on wheels so as to follow the positions of the eye-end of the telescope, together with a battery of several Leyden jars; shelves with Bunsen burners, vacuum tubes, and bottles of chemicals … lined its walls.5 Draper learned from Huggins of the commercial availability of the gelatino-bromide dry plate, which would render the wet-collodion plates Chapter 7: Fields of Glory obsolete. Here, photoactive
colleagues were knocking off a star a minute like parts on a moving factory assembly-line. A list of magnitudes for 4,000 stars appeared in 1884, and another, for 45,000 stars, appeared in 1908. Pickering himself seems to have enjoyed making such measures—perhaps they were a form of relaxation for him from his job’s other pressures, as the task was sufficiently repetitive that it required no substantial amount of mental concentration once it had been mastered. In any case, Pickering himself made
