For more than a century, studies of atomic hydrogen have been a rich source of scientific discoveries. These began with the Balmer series in 1885 and the early quantum theories of the atom, and later included the development of QED and the first successful gauge field theory. Today, hydrogen and its relatives continue to provide new fundamental information, as witnessed by the contributions to this book. The printed volume contains invited reviews on the spectroscopy of hydrogen, muonium, positronium, few-electron ions and exotic atoms, together with related topics such as frequency metrology and the determination of fundamental constants. The accompanying CD contains, in addition to these reviews, a further 40 contributed papers also presented at the conference "Hydrogen Atom 2" held in summer 2000. Finally, to facilitate a historical comparison, the CD also contains the proceedings of the first "Hydrogen Atom" conference of 1988. The book includes a foreword by Norman F. Ramsey.

In No Easy Answers, Allan Franklin offers an accurate picture of science to both a general reader and to scholars in the humanities and social sciences who may not have any background in physics. Through the examination of nontechnical case studies, he illustrates the various roles that experiment plays in science. He uses examples of unquestioned success, such as the discoveries of the electron and of three types of neutrino, as well as studies that were dead ends, wrong turns, or just plain mistakes, such as the "fifth force," a proposed modification of Newton's law of gravity. Franklin argues that science is a reasonable enterprise that provides us with knowledge of the natural world based on valid experimental evidence and reasoned and critical discussion, and he makes clear that it behooves all of us to understand how it works.

In this collection of essays Allan Franklin defends the view that science provides us with knowledge about the world which is based on experimental evidence and on reasoned and critical discussion. In short, he argues that science is a reasonable enterprise. He begins with detailed studies of four episodes from the history of modern physics: (1) the early attempts to detect gravity waves, (2) how the physics community decided that a proposed new elementary particle, 17-keV neutrino, did not exist, (3) a sequence of experiments on K meson decay, and (4) the origins of the Fifth Force hypothesis, a proposed modification of Newton's Law of Universal Gravitation. The case studies are then used to examine issues such as how discord between experimental results is resolved, calibration of an experimental apparatus and its legitimate use in validating an experimental result, and how experimental results provide reasonable grounds for belief in both the truth of physical theories and in the existence of the entities involved in those theories. This book is a challenge to the critics of science, both postmodern and constructivist, to provide convincing alternative explanations of the episodes and issues discussed. It should be of interest to philosophers, historians, and sociologists of science, and to scientists themselves.

Most of the relevant topics on the dark matter in the universe are discussed. The present knowledge of the problem is presented and possible solutions are discussed. The actual experimental efforts devoted to determining the nature of the dark matter — baryonic (for instance, brown dwarfs) or non-baryonic (such as supersymmetric particles) — and to detecting it are illustrated, paying particular attention to necessary technological developments.

Beyond Einstein: Perspectives on Geometry, Gravitation, and Cosmology explores the rich interplay between mathematical and physical ideas by studying the interactions of major actors and the roles of important research communities over the course of the last century.