This all-new and long-awaited sequel to Carl Sagan and Ann Druyan's international bestseller Cosmos takes readers to worlds only now emerging with the advent of new technologies. With lucid prose that recalls the best-selling and beloved Cosmos, Ann Druyan takes readers on an extraordinary journey through the vast and unexplored realms of Earth and space, past and future, fact and imagination. Written and published in coordination with the sensational international television debut of a second season of National Geographic's Cosmos, Cosmos: Possible Worlds travels through more than 14 billion years of cosmic evolution and into an astonishing future where probes travel by light beams to distant stars, helping us solve enduring mysteries of our origins and dream of an unimaginable time ahead. Along the way, we meet the colorful characters who push beyond the boundaries of knowledge—both the little-known but monumental visionaries of the past and the scientists whose work is shaping our future. Color photographs, art, and diagrams based on graphics created for the television series—plus a foreword by Neil deGrasse Tyson, best-selling author, wildly popular science commentator, and host of Cosmos on the National Geographic Channel—complete this highly anticipated package.

Aliens are big in America. Whether they've arrived via rocket, flying saucer, or plain old teleportation, they've been invading, infiltrating, or inspiring us for decades, and they've fascinated moviegoers and television watchers for more than fifty years. About half of us believe that aliens really exist, and millions are convinced they've visited Earth. For twenty-five years, SETI has been looking for the proof, and as the program's senior astronomer, Seth Shostak explains in this engrossing book, it's entirely possible that before long conclusive evidence will be found. His informative, entertaining report offers an insider's view of what we might realistically expect to discover light-years away among the stars. Neither humanoids nor monsters, says Shostak; in fact, biological intelligence is probably just a precursor to machine beings, enormously advanced artificial sentients whose capabilities and accomplishments may have developed over billions of years and far exceed our own. As he explores what, if anything, they would tell us and what their existence would portend for humankind and the cosmos, he introduces a colorful cast of characters and provides a vivid, state-of-the-art account of the past, present, and future of our search for extraterrestrial intelligence.

Two world-renowned scientists present an audacious new vision of the cosmos that “steals the thunder from the Big Bang theory.” — Wall Street JournalThe Big Bang theory—widely regarded as the leading explanation for the origin of the universe—posits that space and time sprang into being about 14 billion years ago in a hot, expanding fireball of nearly infinite density. Over the last three decades the theory has been repeatedly revised to address such issues as how galaxies and stars first formed and why the expansion of the universe is speeding up today. Furthermore, an explanation has yet to be found for what caused the Big Bang in the first place.In Endless Universe , Paul J. Steinhardt and Neil Turok, both distinguished theoretical physicists, present a bold new cosmology. Steinhardt and Turok “contend that what we think of as the moment of creation was simply part of an infinite cycle of titanic collisions between our universe and a parallel world” ( Discover ). They recount the remarkable developments in astronomy, particle physics, and superstring theory that form the basis for their groundbreaking “Cyclic Universe” theory. According to this theory, the Big Bang was not the beginning of time but the bridge to a past filled with endlessly repeating cycles of evolution, each accompanied by the creation of new matter and the formation of new galaxies, stars, and planets.Endless Universe provides answers to longstanding problems with the Big Bang model, while offering a provocative new view of both the past and the future of the cosmos. It is a “theory that could solve the cosmic mystery” ( USA Today ).

A Kabbalistic Universe is about how and why Existence came into being. It sets out the general scheme of the four Worlds of Emanation, Creation, Formation and Action and heir various archangelic, angelic, demonic and organic inhabitants. Drawing upon ancient, medieval and modern material this book brings the Kabbalistic tradition up to date so that the current generation can perceive what Existence is about and how they might play a conscious part in humanity's role of aiding God to behold God in the Mirror of Existence. This is a revised edition with additional graphics. These make the Divine principles involved more comprehensible. Once the terms and metaphysics are mastered, then new perceptions are possible regarding not only the structure and dynamics of Existence but also the workings of the angelics and demonics, Nature and the process of human evolution and its purpose.

Astronomy is the oldest and most fundamental of the natural sciences. From the early beginnings of civilization astronomers have attempted to explain not only what the Universe is and how it works, but also how it started, how it evolved to the present day, and how it will develop in the future. The author, a well-known astronomer himself, describes the evolution of astronomical ideas, briefly discussing most of the instrumental developments. Using numerous figures to elucidate the mechanisms involved, the book starts with the astronomical ideas of the Egyptian and Mesopotamian philosophers, moves on to the Greek period, and then to the golden age of astronomy, i.e. to Copernicus, Galileo, Kepler, and Newton, and ends with modern theories of cosmology. Written with undergraduate students in mind, this book gives a fascinating survey of astronomical thinking.

1. Introduction.- 2. Observational Data.- 3. Celestial Mechanics Minimum.- 4. Elementary Particle Dynamics. I Rigid Body Collisions.- 5. Elementary Particle Dynamics. II Ring Cosmogony.- 6. Elementary Particle Dynamics. III Wave, Photometric, and Other Effects.- 7. Collective Dynamics of Disc Particles. I Formalism.- 8. Collective Dynamics of Disc Particles. II Stability Analysis.- 9. Resonance Effects in Planetary Rings. I Spiral Waves.- 10. Resonance Effects in Planetary Rings. II Narrow Ringlets and Satellites.- 11. Formation and Stability of the Uranian Rings.- 12. Origin, Dynamics, and Stability of the Neptunian Rings.- 13. Self-organisation of the Solar System.- 14. Space Studies of the Outer Planets.- Conclusion.- Appendices I. The Possibility of Studying the Dynamics of Astrophysical Discs in a Two-Dimensional Approach.- 1. Introduction.- 2. Original Equations for the "Volume" Functions.- 2.1 Initial Dynamic Equations.- 2.2 Equation of State.- 3. Derivation of the Basic Equations for the "Plane" Functions.- 3.1 Order-of-Magnitude Estimates of the Terms in the Initial Equations.- 3.2 The Two Limiting Cases of Astrophysical Discs.- 3.3 Limitations of the Characteristic Times of Processes Studied in the Two-Dimensional Approximation.- 3.4 Closed System of Integro-differential Equations for a Barotropic Disc.- 4. Closed Set of Differential Equations for a Polytropic Disc in an External Gravitational Field.- 4.1 Derivation of the Two-Dimensional Equations.- 5. Closed Set of Differential Equations for a Polytropic Self-gravitating Disc.- 5.1 Derivation of the Two-Dimensional Equations.- 5.2 Why Does the Gradient of the Plane Pressure Not Have the Physical Meaning of a Force?.- 6. Conclusion.- 1. Derivation of a Closed Set of Integro-differential Equations.- 2. Derivation of the Dispersion Equation Describing the Three-Dimensional Perturbations.- 4. Dispersion Relation for Waves in the Plane of the Disc.- 5. The Role of Perturbations Along the Rotation Axis.- 5.1 Condition for Neglecting Mass Transfer Along the Rotation Axis.- 5.1.1 General Case.- 5.1.2 Isothermal Disc.- 6. Conclusion.- III. Derivation of the Linearised Equations for Oscillations of a Viscous Disc.- 1. Derivation of the Linearised Equations for Oscillations of a Viscous Uniformly Rotating Disc.- 2. Derivation of the Linearised Equations for Oscillations of a Viscous Differentially Rotating Disc of Inelastic Particles with Account of External Matter Fluxes.- 3. Derivation of the General Dispersion Equation.- IV. Evaluating the Gravitational Potential Inside and Outside a Triaxial Ellipsoid.- 1. Potential Inside the Ellipsoid.- 2. Potential Outside the Ellipsoid.- V. A Drift Mechanism for the Formation of the Cassini Division.- 1. Introduction.- 2. Statement of the Problem.- 3. Derivation of the Non-linear Momentum Conservation Equations.- 4. Time-Averaged Non-linear Momentum Conservation Equations.- 5. Absence of Averaged Radial Mass Flux in a Dissipationless Disc. Large-Scale Convection.- 6. Radial Mass Transfer in a Viscous Disc.- 7. Evolution of the Surface Density of a Disc.- 8. Conditions for the Formation of Different Types of Resonant Structures: Gaps or Wavetrains?.- 9. Estimate of the Maximum Width of a Gap Produced by a Density Wave.- 10. Some Additional Remarks.- VI. Resonance Structures in Saturn's C Ring.- References.