The Discovery of The Galaxies

Theories have always abounded about the place of the earth in the universe. Most saw the earth as its center with the sun and moon and stars moving in a fixed orbit around it. While early astronomers such as Copernicus challenged that view, it was only with the invention of the telescope and its use by Galileo to observe the galaxies that it was established that the earth revolved around the sun and not the opposite. However, it was only with the invention of more sophisticated telescopes in the 18th and 19th centuries, with attached spectroscopes, that a clearer view and a greater understanding of the galaxies would be realized. These powerful instruments helped to confirm the theories of such astronomers as William Hershel and of Lord Rosse that galaxies were collections of stars, and that nebulae were composed of gases and dust and were the birthplace of stars. This primary source portfolio tells the story of the astronomers' fascination with the heavens from the late 19th century to modern times. By examining the variety of letters, charts, illustrations, essays, and photographs, students will gain an understanding of the interest that propelled these humans to devote their lives to understanding the makeup of the universe. This portfolio provides a comprehensive Reproducible Activities Booklet, which includes vocabulary, writing, research, and creative thinking exercises. 5 Illustrated Broadsheet Essays: * The Universe * The Problem of the Nebulae * The Telescope Makers * Splitting Starlight * The Galaxies 11 Primary Source Documents: * Two maps of the heavens, 1790 * A nebula and a galaxy as seen by William Herschel, Lord Rosse, William Huggins, and Edwin Hubble * A letter from William Herschel to Johann Bode * A letter from Rosse to John Herschel * A photograph of part of the Milky Way * Charts showing some bright nebulae and galaxies * Photographs showing a supernova in Ursa Major * Photograph of a cluster of galaxies in the depths of space * The great nebula in Orion * Star chart in the form of a planisphere * Sealed envelope: a problem for astronomers