Toward an Epistemic Web

In the beginning knowledge was local. With the development of more complex forms of economic organization knowledge began to travel. The Library of Alexandria was the fulfillment - however partial and transitory - of a vision to bring together all the knowledge of the world. But to obtain the knowledge one had to go to Alexandria. Today the World Wide Web promises to make universally accessible the knowledge of a world grown larger. To be sure, much work remains to be done: many documents need to be made available (i.e. digitized if they are not already, and freed from restrictive access controls); and various biases (economic, legal, linguistic, social, technological) need to be overcome. But what do we do with this knowledge? Is it enough to create a digital library of Alexandria, with (perhaps) improved finding aids? We propose that the crucial question is how to structure knowledge on the Web to facilitate the construction of new knowledge, knowledge that will be critical in addressing the challenges of the emerging global society. We begin by asking three questions about the Web and its future. In the remainder of the paper we explore the possibility of an Epistemic Web in the context of a more general discussion of knowledge representation technologies, technologies used for storing, manipulating and spreading knowledge

Einstein and the Perihelion Motion of Mercury: Excerpts from ‘How Einstein Found His Field Equations. Sources and Interpretation’ (Forthcoming)

Abstract On November 23, 2021, the Einstein-Besso manuscript on the perihelion motion of Mercury will be auctioned at Christie’s. Expected to fetch around $3M, it promises to be the most expensive scientific manuscript ever sold at auction. In this preprint, we present the parts of our forthcoming book, How Einstein Found His Field Equations. Sources and Interpretation (Springer, 2021) dealing with Einstein’s attempts, in 1913 and in 1915, to account for the anomalous advance of Mercury’s perihelion. In 1913, as documented in the Einstein-Besso manuscript, Einstein and his friend Michele Besso found that the Einstein-Grossmann or Entwurf (= outline or draft) theory, a preliminary version of general relativity, could only account for 18 of the 43 seconds-of-arc-per-century discrepancy between Newtonian theory and observation. In November 1915, however, putting the techniques developed in his collaboration with Besso to good use, Einstein showed that his new general theory of relativity could account for all missing 43′′. After a brief introduction, we provide an annotated transcription of the key pages of the Einstein-Besso manuscript and an annotated new translation of the November 1915 perihelion paper. For permission to post these materials on the arXiv, we are grateful to our publisher, Springer, the Albert Einstein Archives at the Hebrew University of Jerusalem (and its director, Hanoch Gutfreund) and the Einstein Papers Project at Caltech (and its director, Diana Buchwald)

Controlling the phase of a light beam with a single molecule

We employ heterodyne interferometry to investigate the effect of a single organic molecule on the phase of a propagating laser beam. We report on the first phase-contrast images of individual molecules and demonstrate a single-molecule electro-optical phase switch by applying a voltage to the microelectrodes embedded in the sample. Our results may find applications in single-molecule holography, fast optical coherent signal processing, and single-emitter quantum operations

Navigation/traffic control satellite mission study. Volume 3 - System concepts

Satellite network for air traffic control, solar flare warning, and collision avoidanc