The Facts On File Dictionary of Astronomy, Fifth Edition is a new edition in the ""Dictionary Science"" series. This volume uses clear descriptions of different celestial bodies, observational techniques and instruments, and scientific and mathematical theories by which other dictionaries in this discipline have been measured. Now in its fifth edition, this book has been thoroughly updated and expanded with more than 3,700 cross-referenced entries - 200 more than the previous edition...that reflect all aspects of astronomy together with associated terms in spectroscopy, photometry, and particle physics. The topics covered include: Avalanche, Dark energy, Early universe, Imaging, Orbital resonance, Rampart crater, Spitzer Space Telescope, and Thermal field theory.