Sept. 9th: Why is Warm Glass Stickier Than Cold Glass? -
Mary Hogan
52 Posts
Sept. 9th: Why is Warm Glass Stickier Than Cold Glass?
Presentation by: Eric Cornell (2001 Physics Nobel Laureate!) from JILA, University of Colorado
Abstract: What we think of as "empty" space is really filled with a fluctuating electric field. These tiny electric fields are spooky-seeming but entirely real. They give rise to the stickiness of a perfectly clean glass surface. I'll talk about a set of experiments we did on this so-called Casimir-Polder force; time permitting I'll explore connections to eschatology as well.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Sept. 16th: The Supernovae at Night are Big and Bright Deep in the Heart of Baja Oklahoma -
Mary Hogan
52 Posts
Sept. 16th: The Supernovae at Night are Big and Bright Deep in the Heart of Baja Oklahoma
Presentation by: Craig Wheeler from the University of Texas
Abstract: Using a very modest 16-inch aperture robotic telescope, we discovered a whole new category of supernovae that are rare, but of order a hundred times brighter than previously known supernova types. These new events have heterogeneous properties. Some almost surely result from the collision of an "ordinary" supernova with a dense shell of matter that was ejected from the progenitor star prior to explosion. If fortuitously placed, this shell can very efficiently convert kinetic energy of expansion into radiant energy. Others of this new category may be the result of the explosion of exceedingly massive stars by the long-ago proposed mechanism of pair formation by which stars become hot enough to produce electron/positron pairs that destabilize the star. One-dimensional models predict complete thermonuclear destruction, but 3D models yield a violent turbulent burning that may alter the paradigm for this mechanism. Study of these ultra-luminous supernovae will give deeper insights into stellar evolution, and perhaps a new window into the young Universe when very massive stars were thought to be the rule, not the exception.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Sept. 23rd: Electrical & Electromagnetic Responses of Molecules in Confined Geometries:Applications -
Mary Hogan
52 Posts
Sept. 23rd: Electrical and Electromagnetic Responses of Molecules in Confined Geometries - Applications to Molecule-Based Electronic Devices
Presentation by: David L. Allara from Penn State University
Abstract: There has been increasing interest in the past decade in using molecules as active components in electronic devices. A number of fabricated junction structures have been developed to measure I-V behavior including molecular conductance as well as bistable behavior leading to switching and memory. Inherent in these studies are challenges to definitively determine the molecular structure of the embedded molecules and assemblies, especially as a function of applied bias in the case of bistable systems, to control the nature of the electrode-molecule bonding and to develop methods for direct measurements of charge transport dynamics along the molecular frameworks. Since the junctions in the limit reach quasi 1-D (for single molecule junctions) it is necessary to develop techniques that can reach individual molecule level sensitivies and selectively probe the target of interest in complicated multi-material structures. In order to meet these challenges rigorously a collection of different types of complementary probes must be used. In this talk I will discuss the development and application of multiple probes, ranging across scanning tips, in-situ photon and electron scattering and resonant photoelectron spectroscopy.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Oct. 7th: Linear and Non-Linear Gravitational Corrections to Conventional Gravitational Lensing -
Mary Hogan
52 Posts
Oct. 7th: Linear and Non-Linear Gravitational Corrections to Conventional Gravitational Lensing
Presentation by: Bin Chen from the University of Oklahoma
Abstract: I will talk about the Swiss cheese gravitational lensing theory on which our group has been working recently. We claim that a correction to both bending angles and time delays are necessary at the percentage level. We also have found a non-negligible effect of the cosmological constant on cluster lensing. I will also briefly talk about cosmic lensing in a perturbed FLRW universe and the integrated Sachs-Wolfe effect induced by large scale structures.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Oct. 14th: A Non-Technical (Honest!) Discussion of the Problem of Quantum Gravity -
Mary Hogan
52 Posts
Oct. 14th: A Non-Technical (Honest!) Discussion of the Problem of Quantum Gravity
Presentation by: Richard Woodard from the University of Florida
Abstract: I review the problem of quantum gravity at the level of a first year graduate student. My talk is based on an article in Reports on Progress in Physics, vol. 72 (2009) 126002, arXiv:0907.4238. Among other things, I answer seven questions: (1) How can quantum general relativity be so bad when classical general relativity is so good? (2) Why must we quantize gravity? (3) Why do quantum field theories have divergences? (4) Why are the divergences of quantum general relativity worse than those of other quantum field theories? (5) How bad is the problem? (6) What are the main approaches to it? (7) What would we do with a quantum theory of gravity if we had it?
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Presentation by: Andrei Linde from Stanford University
Abstract: I will describe the basic principles of inflationary cosmology and recent progress in constructing realistic inflationary models, including inflation in string theory and supergavity, Higgs inflation and the curvaton scenario. I will also give a brief overview of the present observational status of inflationary cosmology.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Oct. 28th:The Technical, Scientific, and Cultural Legacy of the Space Shuttle -
Mary Hogan
52 Posts
Oct. 28th:The Technical, Scientific, and Cultural Legacy of the Space Shuttle
Presentation by: Steve Hawley from the University of Kansas
Abstract: After nearly 30 years and 134 missions, the Space Shuttle will be retired in 2011. In 1978, I was selected as part of the first class of astronauts specifically chosen for the Shuttle. During my NASA career I flew five Shuttle missions, including three missions as part of NASA's Great Observatories Program, served in flight operations management positions and also as the first Chief Astronaut for the NASA Engineering and Safety Center. In this talk I will describe some of the technical achievements, some of the science that the Shuttle enabled, and a variety of cultural and political milestones that occurred during those 30 years.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Nov. 4th: Cosmic rays and atmospheric leptons: probes of the standard model and beyond -
Mary Hogan
52 Posts
Nov. 4th: Cosmic rays and atmospheric leptons: probes of the standard model and beyond
Presentation by: Mary Hall Reno from the University of Iowa
Abstract: Cosmic ray interactions led to particle discoveries in the era before particle accelerators were built. More recently, neutrino fluxes from cosmic ray interactions in the atmosphere have led to our understanding that neutrinos have mass. I will review how the atmospheric flux of neutrinos and muons is evaluated theoretically. I will present our results on very high energy lepton fluxes from charmed particle production and decay in the atmosphere. Finally, I will discuss some examples of the potential for the measurement of the atmospheric lepton fluxes to constrain non-standard particle physics models.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Nov. 11th: The missing baryons around galaxies and galaxy clusters -
Mary Hogan
52 Posts
Nov. 11th: The missing baryons around galaxies and galaxy clusters
Presentation by: Joel Bregman from the University of Michigan
Abstract: The baryon content is composed of the sum of stars and the gaseous components, which can be measured in potential wells from the richest clusters to the poorest galaxies. For the richest clusters of galaxies, most of the baryons are accounted for in that the baryon fraction approaches the cosmological value, within theoretical expectations. Progressing toward shallower potential wells, the baryon fraction decreases slowly until temperatures of about 1E6 K, below which the baryon fraction decreases quickly. This trend of decreasing baryon content continues through galaxies, where the Milky Way is missing about 75% of its baryons and the typical (lower mass) galaxy is missing 90% of its baryons. The missing baryons do not surround the galaxies as hot halos and we argue that the material never fell into these galaxies, having been pre-heated by an early population of supernovae. Furthermore, we show that the heating and metallicity contributions from this early population of stars may be largely independent of galaxies as well.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Nov. 18th: Casimir Forces and the Perversity of Solid State Physics -
Mary Hogan
52 Posts
Nov. 18th: Casimir Forces and the Perversity of Solid State Physics
Presentation by: Raul Esquivel-Sirvent from Northwestern University (sabbatical)
Abstract: Several table-top experiments have been proposed recently to search for new forces and extra dimensions at the nano scale and to look for chameleon particles trying to measure the pressure between two plates due chameleon fields. These experimental proposals rely on the understanding of other forces involved in the experiments such as the electrostatic force and the Casimir force. In this talk I will discuss how several known properties of the materials will make the success of these experiments very unlikely and how the real properties of solids affect the Casimi force when we go beyond simple models for the dielectric functions. On the positive side of things, I will also show how we can modify the Casimir force and the Casimir torque using, for example, magneto plasmons and external magnetic fields.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~
Dec. 2nd: Early Star-forming Galaxies and the Reionization of the Universe -
Mary Hogan
52 Posts
Dec. 2nd: Early Star-forming Galaxies and the Reionization of the Universe
Presentation by: Richard Ellis from Caltech
Abstract: A few hundred million years after the Big Bang, the hydrogen in deep space was ionized into its component protons and electrons. Theorists speculate this landmark event was caused by the birth of the first galaxies. Can powerful telescopes, probing back in cosmic history, directly witness this event? Large telescopes have already traced the evolutionary history of galaxies back to when the Universe was 1 billion years old. The first results from the Wide Field Camera 3 onboard Hubble Space Telescope give a glimpse at primitive stellar systems at yet earlier times. The lecture will address the progress and challenges of this fundamental quest for our origins, and discuss the future prospects with the James Webb Space Telescope and the next generation of 30 meter aperture ground-based telescopes.
~ It only takes one bottle cap moving at 23,000 mph to ruin your whole day ~