What Is a Black Hole?

Although black holes are objects of central importance across many fields of physics, there is no agreed upon definition for them, a fact that does not seem to be widely recognized. Physicists in different fields conceive of and reason about them in radically different, and often conflicting, ways. All those ways, however, seem sound in the relevant contexts. After examining and comparing many of the definitions used in practice, I consider the problems that the lack of a universally accepted definition leads to, and discuss whether one is in fact needed for progress in the physics of black holes. I conclude that, within reasonable bounds, the profusion of different definitions is in fact a virtue, making the investigation of black holes possible and fruitful in all the many different kinds of problems about them that physicists consider, although one must take care in trying to translate results between fields

What We Don\u27t Know About Class Actions but Hope to Know Soon

Legislation that would alter class action practice in the federal courts has been pending in Congress. Nearly a decade’s worth of U.S. Supreme Court cases have restricted the scope and ease of use of the class action device. Class action critics argue that class litigation is a “racket” that fails to compensate plaintiffs and instead enriches plaintiffs’ lawyers at the expense of legitimate business practices. On the other hand, defenders of class actions decry the legislative and judicial forces aligned against them, warning that trends in class action law will eviscerate the practical rights held by consumers and workers. In short, there is considerable controversy over whether class actions are an economic menace or a boon to the little guys. We have two purposes in this brief Article. First, we wish to focus continuing attention on the need for more empirical information about the actual functioning of the federal class action system. Second, we wish to share our current efforts to use a one-of-a-kind collection of docket reports, originally harvested from Public Access to Court Electronic Records (PACER), to fill the empirical gap. Presentation of empirical findings resulting from this effort awaits a future article. However, this Article includes suggestions as to how the federal judiciary and Administrative Office of the United States Courts (“AO”) could improve data management and data reporting so as to make information about federal class actions more accessible to scholars and others interested in how the class action device operates in practice and what reforms, if any, would be advisable

What keeps nanopores boiling

The liquid to vapour transition can occur at unexpected conditions in nanopores, opening the door to fundamental questions and new technologies. The physics of boiling in confinement is progressively introduced, starting from classical nucleation theory, passing through nanoscale effects, and terminating to the material and external parameters which affect the boiling conditions. The relevance of boiling in specific nanoconfined systems is discussed, focusing on heterogeneous lyophobic systems, chromatographic columns, and ion channels. The current level of control of boiling in nanopores enabled by microporous materials, as metal organic frameworks, and biological nanopores paves the way to thrilling theoretical challenges and to new technological opportunities in the fields of energy, neuromorphic computing, and sensing