Regions

On August 24, 2006, the solar system lost its ninth planet! The astronomers' decision at the IAU General Assembly in Prague to demote Pluto had been precipitated by the discovery, beyond the orbit of Neptune, of a very rich population of Pluto-like objects. The study of the recently discovered remote celestial bodies grows ever more fascinating. Their great variety in color, shape, size, and orbit has astonished observers. What is more, studies of the composition of these new-found objects reveals that they among the most primitive objects in the solar system. In their simple and lively style, the authors of At the Edge of the Solar System alternate discussions on historical aspects and physical descriptions of the remote regions, as well as amazing findings from the cutting edge of research. Beginning with a description of the structure of the solar system, the authors look at the discoveries of Pluto and its moon Charon and show how our knowledge of this mysterious world grew over the last 80 years of its study. They then describe the origins of our solar system and look at the discoveries of the first unusual objects in the outer solar system - Chiron and the first Centaurs. They trace the discoveries of the first Kuiper Belt objects and introduce the wide range of bodies found in the outer solar system, including "Plutinos." Examining these objects in more detail, they then present the arguments concerning the status of Pluto and conclude with discussion of the essential characteristics of the Kuiper Belt and a look at how future observations may lead to yet more discoveries and a greater understanding of these bodies.

This book offers an intimate guide to the Milky Way, taking readers on a grand tour of our home Galaxy's structure, genesis, and evolution, based on the latest astronomical findings. In engaging language, it tells how the Milky Way congealed from blobs of gas and dark matter into a spinning starry abode brimming with diverse planetary systems--some of which may be hosting myriad life forms and perhaps even other technologically communicative species. William Waller vividly describes the Milky Way as it appears in the night sky, acquainting readers with its key components and telling the history of our changing galactic perceptions. The ancients believed the Milky Way was a home for the gods. Today we know it is but one galaxy among billions of others in the observable universe. Within the Milky Way, ground-based and space-borne telescopes have revealed that our Solar System is not alone. Hundreds of other planetary systems share our tiny part of the vast Galaxy. We reside within a galactic ecosystem that is driven by the theatrics of the most massive stars as they blaze through their brilliant lives and dramatic deaths. Similarly effervescent ecosystems of hot young stars and fluorescing nebulae delineate the graceful spiral arms in our Galaxy's swirling disk. Beyond the disk, the spheroidal halo hosts the ponderous--and still mysterious--dark matter that outweighs everything else. Another dark mystery lurks deep in the heart of the Milky Way, where a supermassive black hole has produced bizarre phenomena seen at multiple wavelengths. Waller makes the case that our very existence is inextricably linked to the Galaxy that spawned us. Through this book, readers can become well-informed galactic "insiders"--ready to imagine humanity's next steps as fully engaged citizens of the Milky Way.