Talks

One of the most hotly debated topics of the late nineteenth century concerned the geometry of physical space, an issue that arose with the discovery of non-Euclidean geometries. Lobachevsky and Bolyai opened the way, but it was not until the 1860s that scientists began to take this revolutionary theory seriously. Assuming the free mobility of rigid bodies, Helmholtz concluded that the geometry of space was Euclidean or else of constant curvature (either positive of negative). In 1899 these cases were tested by the astronomer Karl Schwarzschild who used data on stellar parallax to estimate the minimum size of the universe. Many argued that the notion of a curved space was nonsensical, whereas Poincaré, the most prominent mathematician of the era, thought that the geometry of space could never be determined absolutely. These classical debates played a major role in the discussions spawned by Einstein’s general theory of relativity. David Rowe, geometry, space-mathematics, Euclid, Carl Friedrich Gauss, Gaussian curvature, Gaussian Theory, Einstein, differential geometry, playfair, spherical triangles, platonic solids, Netwon, non-Euclidean geometry, Riemann, Ricci, Poincare, Klein

What was happening in Philosophy in 1905? This lecture will seek to answer that question by picking out some of the most influential works of philosophy that were published in or shortly before that year, describing both those works themselves and their intellectual context. The works discussed will include Henri Poincare\'s Science and Hypothesis, Edmund Husserl\'s Logical Investigations, Gottlob Frege\'s Fundamental Laws of Arithmetic and Bertrand Russell\'s \'On Denoting\'. What I hope to bring out is how the seminal works of that period established the tone and content of twentieth century philosophy and drew the battlelines of the great philosophical disputes of the last hundred years: Intuitionism versus Logicism, Phenomenology versus Analytic Philosophy, etc. Ray Monk, Philosophy, Poincare, science, Bertrand Russell, intuitism, logicism, metaphysics, analytic, phenomenology, mathematics, Gottlob Frege, 20th century, arithmetic

We show that the entropy resulting from the counting of microstates of non extremal black holes using field theory duals of string theories can be interpreted as arising from entanglement. The conditions for making such an interpretation consistent are discussed. First, we interpret the entropy (and thermodynamics) of spacetimes with non degenerate, bifurcating Killing horizons as arising from entanglement. We use a path integral method to define the Hartle-Hawking vacuum state in such spacetimes and discuss explicitly its entangled nature and its relation to the geometry. If string theory on such spacetimes has a field theory dual, then, in the low-energy, weak coupling limit, the field theory state that is dual to the Hartle-Hawking state is a thermofield double state. This allows the comparison of the entanglement entropy with the entropy of the field theory dual, and thus, with the Bekenstein-Hawking entropy of the black hole. As an example, we discuss in detail the case of the five dimensional anti-de Sitter, black hole spacetime.

Wireless Communication amazed the world at the turn of the century. That astounding early technology has morphed into one of the hottest communications devices on the market today. Technology historian Robert Friedel and Mike Lazaridis, inventor of the BlackBerry, bring you the story of wireless communication.

In 1905, Norwegian explorer Roald Amundsen completed the first ever transit of the fabled Northwest Passage, culminating a centuries long quest that had claimed ships and lives. Amundsen\'s feat was one of many human achievements in the first decade of the new century, and a landmark in the history exploration. Amundsen\'s voyage was preceded by the controversial North Pole expedition of Robert Peary, another long sought prize of explorers. Amundsen\'s quests shifted south to Antarctica and the South Pole, a prize he achieved, and then back to the Arctic, when he tried and failed to navigate, locked in the polar ice, to the North Pole. This presentation will examine the life, feats, trials, failures and successes of Amundsen. James P.Delgado, Roald Amundsen, northwest passage, north pole, south pole, exploration, Arctic, Frobisher, Peary, Franklin, Clark, Ross, Mclure,

Albert Einstein worked in the Swiss Patent Office in 1905. What was the new world of technology that a patent examiner would have confronted in the young century? Robert Friedel, historian of technology and author of several books on inventions of this period shows why this period a century ago was as exciting and disorienting an age of technological change as our own--maybe even more so! The horseless carriage (we would call it the automobile), the wireless telegraph, motion pictures, electric light and power, as well as a host of surprising new minor inventions, all filled the young twentieth century with an air of novelty and expectation.

How has the most celebrated scientific theory of the 20th century held up under the exacting scrutiny of planetary probes, radio telescopes and atomic clocks? After 100 years, was Einstein right? Clifford Will, Einstein, general relativity, spacetime, gravity wave, mercury perihelion, light, radioastronomy, gravititational lenses, quasars, pulsar