[FPSPACE] Scientists Predict How To Detect A Fourth Dimension Of Space

[LARRY KLAES]

Scientists Predict How To Detect A Fourth Dimension Of Space

Einstein's Theory of Relativity is going to have to defend itself against a 
new five-dimensional theory of gravity.

by Staff Writers

Durham NC (SPX) May 26, 2006

Scientists at Duke and Rutgers universities have developed a mathematical 
framework they say will enable astronomers to test a new five-dimensional 
theory of gravity that competes with Einstein's General Theory of 
Relativity.

Charles R. Keeton of Rutgers and Arlie O. Petters of Duke base their work on 
a recent theory called the type II Randall-Sundrum braneworld gravity model. 
The theory holds that the visible universe is a membrane (hence 
"braneworld") embedded within a larger universe, much like a strand of filmy 
seaweed floating in the ocean.

The "braneworld universe" has five dimensions -- four spatial dimensions 
plus time -- compared with the four dimensions -- three spatial, plus time 
-- laid out in the General Theory of Relativity.

http://www.spacedaily.com/reports/Scientists_Predict_How_To_Detect_A_Fourth_Dimension_Of_Space.html


Astrophysics, abstract
astro-ph/0606641

From: Floyd Stecker [view email]

Date: Tue, 27 Jun 2006 13:26:21 GMT (926kb)

Testing Relativity at High Energies Using Spaceborne Detectors

Authors: F. W. Stecker (NASA/GSFC)

Comments: pdf file, 13 pages, Text of invitated talk presented at the "From 
Quantum to Cosmos: Fundamental Physics Studies from Space" meeting, typo in 
title corrected

(ABRIDGED) The Gamma-ray Large Area Space Telescope (GLAST) will measure the 
spectra of distant extragalactic sources of high energy gamma-rays. GLAST 
can look for energy dependent propagation effects from such sources as a 
signal of Lorentz invariance violation (LIV). Such sources should also 
exhibit high energy spectral cutoffs from pair production interactions with 
low energy photons. The properties of such cutoffs can also be used to test 
LIV. Detectors to measure gamma-ray polarization can look for the 
depolarizing effect of space-time birefingence predicted by loop quantum 
gravity. A spaceborne detector array looking down on Earth to study 
extensive air showers produced by ultrahigh energy cosmic rays can study 
their spectral properties and look for a possible deviation from the 
predicted GZK effect as another signal of LIV.

http://arxiv.org/abs/astro-ph/0606641