Spherical Symmetry and Mass‐Energy in General Relativity. II. Particular Cases

1970 ◽  
Vol 11 (4) ◽  
pp. 1392-1401 ◽  
Author(s):  
Michael E. Cahill ◽  
G. C. McVittie
Keyword(s):  
General Relativity ◽  
Spherical Symmetry ◽  
Mass Energy

scholarly journals CAN THE EXISTENCE OF DARK ENERGY BE DIRECTLY DETECTED?

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3426-3436 ◽  
Author(s):  
MARTIN L. PERL
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Energy Density ◽  
Total Mass ◽  
Mass Density ◽  
Mass Energy ◽  
Dark Energy Density ◽  
Astronomical Observations ◽  
Expansion Of The Universe ◽  
The Universe

Over the last decade, astronomical observations show that the acceleration of the expansion of the universe is greater than expected from our understanding of conventional general relativity, the mass density of the visible universe, the size of the visible universe and other astronomical measurements. The additional expansion has been attributed to a variety of phenomenon that have been given the general name of dark energy. Dark energy in the universe seems to comprise a majority of the energy in the visible universe amounting to about three times the total mass energy. But locally the dark energy density is very small. However it is not zero. In this paper I describe the work of others and myself on the question of whether dark energy density can be directly detected. This is a work-in-progress and I have no answer at present.

New Exact Vacuum Solutions in Brans–Dicke Theory

1997 ◽  
Vol 12 (25) ◽  
pp. 1865-1870 ◽  
Author(s):  
Luis O. Pimentel
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Initial Data ◽  
Cosmological Model ◽  
Exact Solutions ◽  
Spherical Symmetry ◽  
Physical System ◽  
Special Value ◽  
Isotropic Cosmological Model ◽  
Vacuum Solutions

A family of exact solutions to vacuum Brans–Dicke theory with spherical symmetry is found. In the limit of large ω this family reduces to the solutions obtained in general relativity with a scalar field. The solutions show curvature singularities for all times, therefore they do not represent the gravitational collapse of a physical system with regular initial data in the theory. One would like to interpret it as an inhomogeneous dynamical cosmology, but the lack of a regular spacelike slice forbids it. For a special value of an integration constant we have an isotropic cosmological model without the problems mentioned above.

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