222 research outputs found
Does a dynamical system lose energy by emitting gravitational waves?
We note that Eddington's radiation damping calculation of a spinning rod
fails to account for the complete mass integral as given by Tolman. The missing
stress contributions precisely cancel the standard rate given by the
'quadrupole formula'. This indicates that while the usual 'kinetic' term can
properly account for dynamical changes in the source, the actual mass is
conserved. Hence gravity waves are not carriers of energy in vacuum. This
supports the hypothesis that energy including the gravitational contribution is
confined to regions of non-vanishing energy-momentum tensor .
PACS numbers: 04.20.Cv, 04.30.-wComment: Published in Modern Physics Letters A vol 14, no 23, 1531, 1999 Full
text available in the journa
Stability of Gravitational and Electromagnetic Geons
Recent work on gravitational geons is extended to examine the stability
properties of gravitational and electromagnetic geon constructs. All types of
geons must possess the property of regularity, self-consistency and
quasi-stability on a time-scale much longer than the period of the comprising
waves. Standard perturbation theory, modified to accommodate time-averaged
fields, is used to test the requirement of quasi-stability. It is found that
the modified perturbation theory results in an internal inconsistency. The
time-scale of evolution is found to be of the same order in magnitude as the
period of the comprising waves. This contradicts the requirement of slow
evolution. Thus not all of the requirements for the existence of
electromagnetic or gravitational geons are met though perturbation theory. From
this result it cannot be concluded that an electromagnetic or a gravitational
geon is a viable entity. The broader implications of the result are discussed
with particular reference to the problem of gravitational energy.Comment: 40 pages, 5 EPS figures, uses overcite.st
The Energy of a Dynamical Wave-Emitting System in General Relativity
The problem of energy and its localization in general relativity is
critically re-examined. The Tolman energy integral for the Eddington spinning
rod is analyzed in detail and evaluated apart from a single term. It is shown
that a higher order iteration is required to find its value. Details of
techniques to solve mathematically challenging problems of motion with powerful
computing resources are provided. The next phase of following a system from
static to dynamic to final quasi-static state is described.Comment: 36 pages, 2 figures, to appear in Foundations of Physic
Extended Planck Scale
Traditional derivations of the Planck mass ignore the role of charge and spin
in general relativity. From the Kerr-Newman null surface and horizon radii,
quantized charge and spin dependence are introduced in an extended Planck scale
of mass. Spectra emerge with selection rules dependent upon the choice of
Kerr-Newman radius to link with the Compton wavelength. The appearance of the
fine structure constant suggests the possibility of a variation in time of the
extended Planck mass, which may be much larger than the variation in the
traditional one. There is a suggestion of a connection with the value
governing high-energy radiation in Z-boson production and decay.Comment: 9 page
The New Planck Scale: Quantized Spin and Charge Coupled to Gravity
In the standard approach to defining a Planck scale where gravity is brought
into the quantum domain, the Schwarzschild gravitational radius is set equal to
the Compton wavelength. However, ignored thereby are the charge and spin, the
fundamental quantized aspects of matter. The gravitational and null-surface
radii of the Kerr-Newman metric are used to introduce spin and charge into a
new extended Planck scale. The fine structure constant appears in the extended
Planck mass and the recent discovery of the variation with the
evolution of the universe adds further significance. An extended Planck charge
and Planck spin are derived. There is an intriguing suggestion of a connection
with the value governing high-energy radiation in Z-boson production
and decay.Comment: 8 pages, This essay received an "honourable mention" in the 2003
Essay Competition of the Gravity Research Foundatio
General relativistic velocity: the alternative to dark matter
We consider the gravitational collapse of a spherically symmetric ball of
dust in the general relativistic weak gravity regime. The velocity of the
matter as viewed by external observers is compared to the velocity gauged by
local observers. While the comparison in the case of very strong gravity is
seen to follow the pattern familiar from studies of test particles falling
towards a concentrated mass, the case of weak gravity is very different. The
velocity of the dust that is witnessed by external observers is derived for the
critically open case and is seen to differ markedly from the expectations based
upon Newtonian gravity theory. Viewed as an idealized model for a cluster of
galaxies, we find that with the general relativistic velocity expression, the
higher-than-expected constituent velocities observed can be readily correlated
with the solely baryonic measure of the mass, obviating the need to introduce
extraneous dark matter. Hitherto unexplained and subject-to-reinterpretation
astrophysical phenomena could also be considered within this context. It is
suggested that an attempt be made to formulate an experimental design at
smaller scales simulating or realizing a collapse with the aim of implementing
a new test of general relativity.Comment: 12 pages, 2 figure
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