物理学史与哲学

The main goal of this article is to use the epistemological framework of a specific version of Cognitive Constructivism to address Piaget's central problem of knowledge construction, namely, the re-equilibration of cognitive structures. The…

In General Relativity in Hamiltonian form, change has seemed to be missing, defined only asymptotically, or otherwise obscured at best, because the Hamiltonian is a sum of first-class constraints and a boundary term and thus supposedly…

Redshift observations of galaxies outside the Local Group are fairly common in extragalactic astrophysics. If redshifts are interpreted as arising from radial velocities, these must be corrected by the contamination of the solar motion. We…

This is the transcript of the after-dinner talk I gave at the close of the 16 Nov 2013 symposium "Celebrating the Science of Kenneth Geddes Wilson" [1] at Cornell University (see Fig. 1 for the poster). The video of my talk is on-line [2],…

Quantum gravity is understood as a theory that, in some sense, unifies general relativity (GR) and quantum theory, and is supposed to replace GR at extremely small distances (high-energies). It may be that quantum gravity represents the…

Translation of Denis Diderot's `Cinqui\`eme M\'emoire ou Lettre sur la R\'esitance de L'Air ou Mouvement des Pendules.'

It is often thought that the existence of other worlds cannot be scientifically verified and therefore should be treated as philosophical speculation. In this article, I describe several methods for determining if other worlds exist, even…

In this paper we present the results of an archaeoastronomical survey of three proto-historical sites located in the high Friulian plain (Galleriano, Gradisca and Savalons), dating from the end of the Early Bronze Age (1900 B.C.) to the end…

In 1893, the "physicist-engineer" Andr\'e Blondel invents the oscilloscope for displaying voltage and current variables. With this powerful means of investigation, he first studies the phenomena of the arc then used for the coastal and…

Black holes are extremely relativistic objects. Physical processes around them occur in a regime where the gravitational field is extremely intense. Under such conditions, our representations of space, time, gravity, and thermodynamics are…

The discovery that the Universe is accelerating in its expansion has brought the basic concept of cosmic expansion into question. An analysis of the evolution of this concept suggests that the paradigm that was finally settled into prior to…

It has been 20 years since planning began for the 1995 United Nations International Conference on Near-Earth Objects. The conference proceedings established the scientific basis for an international organizational framework to support…

If the universe is infinite now it has always been infinite. This is the opinion of many astronomers today as can be concluded from the following series of interviews, but the opinions differ much more than I had expected. Many astronomers…

This article is a brief Retrospective on the life and work of Robert W. Zwanzig, who formulated nonequilibrium statistical mechanics and who passed away in May of this year.

Sicily has played an important role in the development of the new research area named "Econophysics". In fact some key ideas supporting this new hybrid discipline were originally formulated in a pioneering work of the Sicilian born…

Jaynes invented the Brandeis Dice Problem as a simple illustration of the MaxEnt (Maximum Entropy) procedure that he had demonstrated to work so well in Statistical Mechanics. I construct here two alternative solutions to his toy problem.…

At the beginning of the twentieth century while Henri Poincar\'e (1854-1912) was already deeply involved in the developments of wireless telegraphy, he was invited, in 1908, to give a series of lectures at the \'Ecole Sup\'erieure des…

Relaxation oscillations are commonly associated with the name of Balthazar van der Pol via his eponymous paper (Philosophical Magazine, 1926) in which he apparently introduced this terminology to describe the nonlinear oscillations produced…

I will discuss the interactions of a number of individuals that played major roles in the formation of radio astronomy in India in the period 1952-1962, particularly Dr. Joseph L. Pawsey. The story began in 1953-1954: Pawsey brought Govind…

During the 17th century the idea of an orbiting and rotating Earth became increasingly popular, but opponents of this view continued to point out that the theory had observable consequences that had never, in fact, been observed. Why, for…