The New Worlds

Exoplanet, extrasolar planet, exoEarth, exojupiter: neologisms still absent from many dictionaries. These terms are, however, current among astronomers, and are heard in their answers to a question already two millennia old: are there planets like ours elsewhere in the Universe? Greek atomists such as Epicurus were convinced of the existence of an infinite number of solar systems like our own, but it was only in 1995 that a real answer began to emerge. An extrasolar planet had been detected... a planet orbiting another star... a star like the Sun. So, the solar system was not unique! By mid- 2006 more than 200 giant exoplanets had been discovered. At this rate of discovery it seems that Earth-like planets may be found within a decade. The discovery of exoplanets held some surprises, in that they exhibited very different characteristics from what might have been expected. Although most of them are gas giants of masses comparable to Jupiter's mass, as a result of the rather insensitive nature of current detection methods, why are they from ten to fifty times closer to their stars than is Jupiter? How were these 'hot Jupiters' formed? Another surprise about exoplanets is that many of them have very elliptical orbits, while the planets of the solar system have much more circular orbits.

Offering an engaging story of the hunt for new worlds, this book examines the range of extrasolar planets that have been discovered during the past decade and looks at what can be learned about such planets by studying the bodies in our own solar system.

Offering an engaging and complete story of the hunt for new worlds, this volume fully details the detection and exploration of extrasolar planets. Coverage begins by first looking at early searches for extrasolar planets, the very first discoveries, and the observational techniques involved. The book examines the very wide range of extrasolar planets that have been discovered during the past ten years and looks at what can be learned about such planets by studying the bodies in our own solar system. It also discusses the formation of planetary systems, the way in which such systems may evolve and the final systems of planets that result. In addition, the authors demonstrate how life might evolve on an extrasolar planet and how such life might be detected.

Extrasolar planets: the Holy Grail of astronomers.- In search of exoplanets.- Twelve years of discovery.- What do we learn from our own solar system?.- The formation of planetary systems.- Life in the Universe.- Future projects.