Matters of Gravity, The Newsletter of the Topical Group in Gravitation of the American Physical Society, Volume 28, Fall 2006

Research Briefs: Singularity Avoidance in Canonical Quantum Gravity, by Viqar Husain What's New in LIGO, by David Shoemaker Conference reports: Scanning New Horizons: GR Beyond 4 dimensions, by Donald Marolf Quantum Gravity in the Americas III, by Jorge Pullin New Frontiers in Numerical Relativity, by Luciano Rezzolla Teaching General Relativity to Undergraduates, by Greg Comer Ninth Capra Meeting on Radiation Reaction, by Lior BurkoComment: 20 pages. David Garfinkle (Editor

On "the'' electric field of a uniformly accelerating charge

The problem of the electric field of a uniformly accelerating charge is a longstanding one that has led to several issues. We resolve these issues using techniques from linguistics, cognitive psychology, and the mathematics of partial differential equations

Black hole entropy as a consequence of excision

Black hole entropy is shown to be a consequence of restricting our description of physics to the exterior of black holes. This precludes the need for a statistical mechanical description of this entropy in terms of microstates

Inhomogeneous spacetimes as a dark energy model

Tolman-Bondi inhomogeneous spacetimes are used as a cosmological model for type Ia supernova data. It is found that with certain parameter choices the model fits the data as well as the standard $\Lambda$CDM cosmology does.Comment: 9 pages, 6 figures, Added Reference

The Probability for matter-Antimatter Segregation Following the Quark-Hadron Transition

Cosmologists such Sakharov, Alfv\'en, Klein, Weizs\"acker, Gamow and Harrison all disregarded the distribution of baryons and antibaryons immediately prior to freeze-out in trying to elucidate the circumstances that explained hadron distribution in the early universe. They simply accepted a uniform distribution: each baryon paired with an antibaryon. Their acceptance of this assumption resulted in theoretical difficulties that could not be overcome. This essay discards this assumption of homogeneity or uniformity. Although this essay does deal with early-universe matters, it is not meant to indicate any involvement in energy distribution functions nor in any symmetry-asymmetry controversies. Cluster formation is strictly geometric. This essay has value as far as problems early cosmologists faced but also should complete the historic record

Matters of Gravity, The Newsletter of the Division of Gravitational Physics of the American Physical Society, Volume 50, December 2017

DGRAV News: We hear that .... APS April Meeting Town Hall Meeting Conference Reports: Hawking Conference Benasque workshop 2017 QIQG 3 Obituary: Remembering Cecile De Witt-Morett

How extreme are extreme black holes?

We examine the properties of nearly extremal black holes produced by gravitational collapse. It is shown that an observer who crosses the black hole horizon at late times rapidly encounters a singularity.Comment: 10 pages, 3 figure

Matters of Gravity, The Newsletter of the Topical Group on Gravitation of the American Physical Society, Volume 35, Winter 2010

GGR News: - GGR Program at the APS meeting in Washington D.C., by David Garfinkle - we hear that..., by David Garfinkle Research Briefs: - Supernovae modelling, by Ian Hawke Conference Reports: - ADM-50, by Richard WoodardComment: 11 pages, late

The fine structure of Gowdy spacetimes

The approach to the singularity in Gowdy spacetimes consists of velocity term dominated behavior, except at a set of isolated points. At and near these points, spiky features grow. This paper reviews what is known about these spikes.Comment: contribution to A Spacetime Safari: Essays in honor of Vincent Moncrie

Matters of Gravity, The Newsletter of the Division of Gravitational Physics of the American Physical Society, Volume 47, June 2016

DGRAV News: DGRAV we hear that.... Research Briefs: GW150914 Obituaries: Remembering Felix Pirani Remembering David Finkelstein Steve, the physicist Remembering Sergio Dain Editorial: Gravitational physics in the modern universit