"Many Skies: Alternative Histories of the Sun, Moon, Planets, and Stars" by Arthur Upgren

Publisher: New Brunswick, N.J. : Rutgers University Press, [2005]

Copyright: ©2005

ISBN:9780813535128 

Characteristics:viii, 198 pages :,illustrations ;,24 cm

This is an extremely interesting book that examines astronomy and astrophysics from the perspective of what would happen if the world were not as we currently know it. What I mean by this is if our solar system was not comprised of eight planets, a single sun, and various numbers of moons around all but the first two planets how would this have changed human discovery of astronomy, physics, or our understanding of the world itself, and much more.

The book is structured to pose an alternate scenario to what we know as normal in our universe. In it Dr. Upgren deals with our near solar system, and looks at what it would be like if Earth had three moons? Going on from this what if we were in a trinary star system? He then goes on to explain how stellar magnitudes work, and discusses proper motion. He then speculates what science today would been like if Ptolemy's discovery that the sun was at the centre of the solar (fourteen hundred years before Copernicus proposed nearly the same thing) had been accepted. He then concludes the first section by looking at what would have changed if Earth was the only planet orbiting the sun.

He goes on in subsequent sections to talk about other topics such as what would Earth be like if we had rings like Saturn, were close to a very large planet, were part of a double planet system, and so on. He also  writes about globular clusters, celestial mechanics and its history and so on.

Over the years I have dabbled in amateur astronomy, and have had the questions that Dr. Upgren poses in his book come to mind a number of times, but rarely was I ever able to find anyone who could answer them, or would be willing to even consider my interest.

As a writer, I have explored some of these questions more, and believe this book would be a valuable resource for any author of Science Fiction, or Fantasy who has a need to world-build and make it plausible (yes, I realise this actually contradicts the way some people define fantasy, but so be it).

Check it out.