Evry Leon Schatzman

This article describes the life and work of French astrophysicist Evry Schatzman (1920-2010). He was a pioneer in the study of white dwarfs during the 1940s and was one of the proponents of the wave heating theory of the solar corona. He made important contributions to the fields of internal stellar structure, novae, mechanisms of acceleration of cosmic rays, the role of turbulent diffusion in stellar evolution and its consequences for the lithium abundance, and the rate of solar neutrinos. Schatzman is mostly recognized as the creator of the French school of theoretical astrophysics. Although he was not the first theoretician of astrophysics in his country, he was the first to have felt the need for a rapid development of this subject in France, and the first to teach it and to guide the path of many young researchers. Many of them became involved, and some leaders, in space science.Comment: 5 pages. Published in Biographical Encyclopedia of Astronomers, Thomas Hockey (ed.), 201

Editorial note to "A Homogeneous Universe of Constant Mass and Increasing Radius accounting for the Radial Velocity of Extra--Galactic Nebulae" by Georges Lema\^itre (1927)

This is an editorial note to accompany printing as a Golden Oldie in the Journal of General Relativity and Gravitation of the fundamental article by Georges Lema\^itre first published in French in 1927, in which the author provided the first explanation of the observations on the recession velocities of galaxies as a natural consequence of dynamical cosmological solutions of Einstein's field equations, and discovered the so-called Hubble law. We analyze in detail the scientific contents of this outstanding work, we describe how it remained unread or poorly appreciated until 1930, and we list and explain the differences between the 1927 and 1931 versions. Indeed the English translation published in 1931 in MNRAS was not perfectly faithful to the original text - it was updated. As it turned out very recently, the updates were done by Lema\^itre himself, but the discrepancies between the two texts caused a temporary stir among historians. Our new translation - given in the Appendix - follows the 1927 version exactly.Comment: 25 pages, 3 figures, to be published in Gen. Rel. Gra

New Developments in the Search for the Topology of the Universe

Multi-connected Universe models with space idenfication scales smaller than the size of the observable universe produce topological images in the catalogs of cosmic sources. In this review, we present the recent developments for the search of the topology of the universe focusing on three dimensional methods. We present the crystallographic method, we give a new lower bound on the size of locally Euclidean multi-connected universe model of $3000 h^{-1} \hbox{Mpc}$ based on this method and a quasar catalog, we discuss its successes and failures, and the attemps to generalise it. We finally introduce a new statistical method based on a collecting correlated pair (CCP) technique.Comment: 20 pages, 13 figures, Proceedings of the XIXth Texas meeting, Paris 14-18 december 1998, Proceedings of the XIXth Texas meeting, Eds. E. Aubourg, T. Montmerle, J. Paul and P. Peter, article-no: 04/2

Creation, Chaos, Time : from Myth to Modern Cosmology

Every society has a story rooted in its most ancient traditions, of how the earth and sky originated. Most of these stories attribute the origin of all things to a Creator - whether God, Element or Idea. We first recall that in the Western world all discussions of the origin of the world were dominated until the 18th century by the story of Genesis, which describes the Creation as an ordered process that took seven days. Then we show how the development of mechanistic theories in the 18th century meant that the idea of an organized Creation gave way to the concept of evolution, helped by the fact that in the 19th century astrophysicists discovered that stars had their origin in clouds of gas. We conclude with Big bang theory, conceived at the beginning of the 20th century, that was subsequently developed into a more or less complete account of the history of the cosmos, from the supposed birth of space, time and matter out of the quantum vacuum until the emergence of life (at least on our planet Earth, and much probably elsewhere) and beyond.Comment: 15 pages, 0 figur