Monthly Archives: July 2014

Isolated systems are asymptotically… flat

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Martin Reiris

Martin Reiris is Junior Scientist at the Max Planck Institute for Gravitational Physics (Golm-Germany) since 2009. He received the PHD in pure math in 2005 at SUNYSB, and held a Moore Instructor in Math at MIT from 2006 to 2009. His interests are mainly in geometry and the mathematical structure of general relativity

In the extraordinary manuscript The Foundation of the Generalised Theory of Relativity, printed in 1916 in Annalen der Physics, Einstein begins addressing what he calls an epistemological defect of classical mechanics, (as well as of special relativity), whose dignity he attributes to E Mach. He imagined two bodies, A and B, made of the same fluid material and sufficiently separated from each other that none of the properties of one could be attributed to the existence of the other. Observers at rest in one body, he continues, see the other body rotating at a constant angular velocity, yet these same observers measure a perfect round surface in one case and an ellipsoid of rotation in the other case. It is then asked: “Why is this difference between the two bodies?”. Continue reading →

Why are complete compact-binary-coalescence waveforms so important for compact-object astrophysics?

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Marie-Anne Bizouard

Marie-Anne Bizouard is a research fellow at CNRS, Laboratoire de l’Accélérateur Linéaire, Orsay, France.
She is an experimental physicist working on gravitational wave searches with ground based interferometric detectors.

The numerical relativity breakthrough in 2005 has provided waveforms of the gravitational wave signal emitted by a compact binary sources that describe the coalescence, the merger of the two compact objects and the ring-down of the newborn object. These waveforms are now more and more often used in gravitational wave searches carried out with interferometric detectors (LIGO, Virgo, GEO and eventually KAGRA), instead of analytical waveforms from Post Newtonian expansion that Continue reading →

The Weyl curvature and the Cosmic Censorship conjecture

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Parampreet Singh

Parampreet Singh is an Assistant Professor of Physics at Louisiana State University

Whether the gravitational collapse of an astrophysical object leads to a black hole or a naked singularity is one of the most intriguing issues in Einstein’s theory of General Relativity. In many astrophysical situations, the initial conditions are such that a trapped region forms and the gravitational collapse ends in a black hole, in confirmation with the Cosmic Censorship conjecture. However, in recent years Continue reading →