Janna Levin: Black Hole Blues and Other Songs from Outer Space
PIRSA: 17050000  ( MP4 Medium Res , MP3  , PDF ) Which Format? Janna Levin: Black Hole Blues and Other Songs from Outer Space Speaker(s): Janna Levin Abstract:  More than a billion years ago, two black holes
collided. In the final second of their long life...

Being is an Objectification of the EGO
Is 'Being' The Same For Everyone? by Alva Noë May 15, 2017 • Philosophical
skepticism, in part coming from Decartes, considers the idea that it's
impossible to know another person's reality. Alva Noë ponders this in
relation to debates in today's world. ...

The Sound of Blackholes?
During her live public lecture webcast at Perimeter Institute on May 3,
2017, Janna Levin of Columbia University will explain LIGO's “discovery
of the century” and what it means for the future of science. See: Black Hole Blues and Other Songs from Outer S...

Per-sonifying the way we look at the Universe and Blackholes

Traversable acausal retrograde domains in spacetime

Benjamin K Tippett1 and David Tsang2

Published 31 March 2017 • © 2017 IOP Publishing Ltd
Classical and Quantum Gravity, Volume 34, Number 9

Abstract

In this paper we present geometry which has been designed to fit a layperson's description of a 'time machine'. It is a box which allows those within it to travel backwards and forwards through time and space, as interpreted by an external observer. Timelike observers travel within the interior of a 'bubble' of geometry which moves along a circular, acausal trajectory through spacetime. If certain timelike observers inside the bubble maintain a persistent acceleration, their worldlines will close.

Our analysis includes a description of the causal structure of our spacetime, as well as a discussion of its physicality. The inclusion of such a bubble in a spacetime will render the background spacetime non-orientable, generating additional consistency constraints for formulations of the initial value problem. The spacetime geometry is geodesically incomplete, contains naked singularities, and requires exotic matter.

http://iopscience.iop.org/article/10.1088/1361-6382/aa6549#artAbst

Mysterious Cosmic Explosion Puzzles Astronomers
A Quick Look at CDF-S XTI * Credit: NASA/CXC/Pontifical Catholic Univ./F.Bauer et al.   See Also: Mysterious Cosmic Explosion Puzzles Astronomers *   We report on the detection of a remarkable new fast high-energy transient
found in the Chandra Deep Fie...