Free fall and self-force: an historical perspective
Alessandro Spallicci
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43 pages; to appear in final form on "Mass and Motion in General Relativity" by Springer (L. Blanchet, A. Spallicci, B. Whiting Eds.) based on the lectures given at the CNRS School on Mass held the 23-25 June 2008 in Orléans. http://www.springer.com/astronomy/cosmology/book/978-90-481-3014-6
Free fall has signed the greatest markings in the history of physics through the leaning Pisa tower, the Cambridge apple tree and the Einstein lift. The perspectives offered by the capture of stars by supermassive black holes are to be cherished, because the study of the motion of falling stars will constitute a giant step forward in the understanding of gravitation in the regime of strong field. After an account on the perception of free fall in ancient times and on the behaviour of a gravitating mass in Newtonian physics, this chapter deals with last century debate on the repulsion for a Schwarzschild black hole and mentions the issue of an infalling particle velocity at the horizon. Further, black hole perturbations and numerical methods are presented, paving the way to the introduction of the self-force and other back-action related methods. The impact of the perturbations on the motion of the falling particle is computed via the tail, the back-scattered part of the perturbations, or via a radiative Green function. In the former approach, the self-force acts upon the background geodesic; in the latter, the geodesic is conceived in the total (background plus perturbations) field. Regularisation techniques (mode-sum and Riemann-Hurwitz $z$ function) intervene to cancel divergencies coming from the infinitesimal size of the particle. An account is given on the state of the art, including the last results obtained in this most classical problem, together with a perspective encompassing future space gravitational wave interferometry and head-on particle physics experiments. As free fall is patently non-adiabatic, it requires the most sophisticated techniques for studying the evolution of the motion. In this scenario, the potential of the self-consistent approach, by means of which the background geodesic is continuously corrected by the self-force contribution, is examined.
Alternative Explanations of the Cosmic Microwave Background: A Historical and an Epistemological Perspective
我们回顾了对宇宙微波背景起源的各种非传统解释，并讨论了它们的价值，同时分析了它们被拒绝的动力学，以及相关的物理和方法论原因。事实证明，有许多这样的非正统解释;不仅是那些在完全拒绝相对论（“大爆炸”）范式的理论背景下发展起来的解释（例如，宇宙大爆炸理论），而且是那些在宇宙大爆炸理论背景下发展起来的解释。由阿尔芬，霍伊尔和纳利卡），但也有那些来自阵营的原始思想家牢牢扎根在相对论环境（例如，作者：Rees，Ellis，Rowan-Robinson，Layzer and Hively）。事实上，正统解释在其多阶段发展的30年中只是逐步战胜了替代解释。虽然总的来说，没有一个替代热大爆炸的场景是有说服力的今天，我们讨论建立正统和消除替代品在科学中的认识论的后果，一个问题，最近讨论的哲学家和历史学家的科学物理学的其他领域。最后，我们挑选出一些似是而非的和可能富有成效的想法提供的替代品。
Keplers's Equation and Angular Momentum: Historical Perspective, Critical Analysis and Implications for Development of the Orbital Mechanics/Dynamics, Mathematics and Physics
"Observations on the possible electromagnetic nature of nucleon interactions and pions" -- historical manuscript from 1969 by B. W. Ninham and C. Pask
Centre of Excellence ENSEMBLE3 Sp. z o. o.（ENSEMBLE3卓越中心有限责任公司）；Chemical and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw（华沙大学新技术中心化学与生物系统模拟实验室）；Department of Chemical and Geological Sciences and CSGI University of Cagliari（卡利亚里大学化学与地质科学系及CSGI）
