This paper discusses the mistake of understanding the laws and concepts of thermodynamics too literally in the foundations of statistical mechanics. Arguing that this error is still made in subtle ways, the article explores its occurrence in three examples: the Second Law, the concept of equilibrium and the definition of phase transitions.

The Past Hypothesis is the claim that the Boltzmann entropy of the universe was extremely low when the universe began. Can we make sense of this claim when *classical* gravitation is included in the system? I first show that the standard rationale for not worrying about gravity is too quick. If the paper does nothing else, my hope is that it gets the problems induced by gravity the attention they deserve in the foundations of physics. I then try to make (...) plausible a very weak claim: that there is a well-defined Boltzmann entropy that *can* increase in *some* interesting self-gravitating systems. More work is needed before we can say whether this claim answers the threat to the standard explanation of entropy increase. (shrink)

Two of the world's leading astrophysicists, James Binney and Scott Tremaine, here present a comprehensive review of the theory of galactic dynamics at a level suitable for both graduate students and researchers. Their work in this volume describes our present understanding of the structure and dynamics of stellar systems such as galaxies and star clusters. Nicknamed "the Bible of galactic dynamics," this book has become a classic treatise, well known and widely used by researchers and students of galactic astrophysics and (...) stellar dynamics. Praised for its modern approach, as well as for the rigor and exemplary clarity with which the authors handle the material in this book, Galactic Dynamics includes classic results and data while also reflecting the many recent developments in the field. The authors maintain an effective style of exposition throughout, keeping clear what is present knowledge and what is still speculation, while allowing the reader to grasp an overview of the subject before following through with the mathematical detail. Most of the astronomical community since the late 1980s was introduced to galactic dynamics through Galactic Dynamics, and it remains the most widely used graduate textbook in galactic astrophysics today. No other book gathers together and presents our current understanding of the field in such a clear and concise way. Through this approach, Binney and Tremaine succeeded in creating a classic reference of enormous pedagogic value. (shrink)

This work assembles some basic theoretical elements on thermal equilibrium, stability conditions, and fluctuation theory in self-gravitating systems illustrated with a few examples. Thermodynamics deals with states that have settled down after sufficient time has gone by. Time dependent phenomena are beyond the scope of this paper. While thermodynamics is firmly rooted in statistical physics, equilibrium configurations, stability criteria and the destabilizing effect of fluctuations are all expressed in terms of thermodynamic functions. The work is not a review paper but (...) a pedagogical introduction which may interest theoreticians in astronomy and astrophysicists. It contains sufficient mathematical details for the reader to redo all calculations. References are only to seminal works or readable reviews. Delicate mathematical problems are mentioned but are not discussed in detail. (shrink)