On the physical properties of a nonquadratic solution for the McVittie metric

Journal Article · Wed Dec 31 23:00:00 EST 1986 · J. Math. Phys. (N.Y.); (United States)

DOI:https://doi.org/10.1063/1.527798· OSTI ID:6681813

Knutsen, H

A particular class of McVittie's new nonquadratic solutions is examined with respect to its physical characteristics. It is found that center regularity is not compatible with negative pressure and density gradients. These solutions also have the strange geometric feature that the physical radius is a decreasing function of comoving radial coordinate. Models for nonstatic ''gaseous'' spheres (i.e., the density rho vanishes at the outer surface of the perfect fluid sphere together with the pressure p) have been constructed. The global motion is studied, and it has been found that pulsations are not possible. It is shown, however, that the density and pressure gradients are both negative. The pressure and the density are thus positive within the boundary of these ''gaseous'' spheres, and it is also seen that the density is increasing for contracting models. For the layers close to the outer boundary, it is shown that the pressure is increasing when the sphere is contracting. The speed of sound is thus real, and it is further seen that this speed is less than the speed of light. It is found that there exist bouncing models where the rate of change of circumference as measured by an observer riding on the boundary of the ''gaseous'' sphere is zero just at the moment when the sphere starts its reexpansion.

• Research Organization: Stavanger College of Engineering, Box 2527, Ullandhaug, 4001 Stavanger, Norway
• OSTI ID: 6681813
• Journal Information: J. Math. Phys. (N.Y.); (United States), Journal Name: J. Math. Phys. (N.Y.); (United States) Vol. 28:1; ISSN JMAPA
• Country of Publication: United States
• Language: English

Related Subjects

657003* -- Theoretical & Mathematical Physics-- Relativity & Gravitation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANALYTICAL SOLUTION
BOUNDARY CONDITIONS
BOUNDARY-VALUE PROBLEMS
COORDINATES
DENSITY
EINSTEIN FIELD EQUATIONS
EQUATIONS
EXPANSION
FIELD EQUATIONS
FIELD THEORIES
GENERAL RELATIVITY THEORY
GEOMETRY
GRAVITATION
GRAVITATIONAL COLLAPSE
MATHEMATICS
PHYSICAL PROPERTIES
PRESSURE GRADIENTS
PULSATIONS
SPHERES