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1.
In the introductive section a deeper specification is made of the physical meaning of the terms in the Friedmann Equation (FE). After that, assuming validity of Mach's Principle, it is deduced (Section 2) that the FE for the radiation-dominated phase of the evolution of the Universe (which is considered to be closed) is valid even for the matter-dominated era. On the other hand, such a form of the FE is shown to be irrelevant when used for deducing how the frequency of the 3K-photons depends on the radius of the Universe. The solution of the dilemma turns out to have its roots in the way in which the relativistic gravitational potentials are composed, together with the fact that the cosmic potential of the closed Universe is equal to –1. Consequently, the equation one uses for the matter-dominated era is shown to be proper for both the main phases of the cosmological evolution (Section 3). In Section 4, the deduction of the critical density-value is revised, and the new result shortly discussed. In Section 5 it is concluded that there is only one possible value for the maximum radius of our Universe, specific for the initial condition due to the FE. Nevertheless, it is not excluded that other smaller universes can exist. In the final section a modified soabubble analogy with the first law of thermodynamics is used to describe the dynamics of the cosmological expansion, and, in this context, the importance of Mach's Principle is pointed out.  相似文献   

2.
By combining two two-dimensional subspaces, closed into themselves due to curvature, it is possible to create a model of three-dimensional space of the same properties. If the Universe is a space of this type, its effect is that of a monstrous lens. Close objects are observed to diminish according to the normal law of perspective; however, the remote galaxies are seen to be very highly magnified.The apparent angular size2 of a galaxy is more than the size1 in flat space according to relation:2 =1 cosec , where is the angular distance from the observer to the galaxy. The diameter2 d of a galaxy in curved space must be in the same relation to a diameter1 d with no curvature of space:2 d=1 d cosec . The apparent angular size2 and diameter2 d are distorted shapes in consequence of an optical illusion caused by the spatial curvature.It is necessary to distribute the multitude of galaxies into two parts in accordance with their location on the close or reverse hemihypersphere of the Universe. The minimum of apparent angular size2 of a galaxy of diameter1 d is at the equatorial zone.The most likely candidates for location in the reverse hemi-hypersphere are cD's of apparent supergiant sizes due, probably, to the curvature of space. The existence of supergiant sizes of galaxies is the second indirect proof, besides superluminal velocities, that the Universe is closed into itself through curvature. The third indirect evidence, i.e., inductive confirmation of the same fact, is the superposition of galaxies which need not inevitably be a new alternative to the present theories of collisions, cannibalism, merger, etc.The fourth indirect proof of the positive curvature of the Universe is the occurrence of background radiation, because that must vanish in hyperbolic space irrespective of its origin. The gravitational lens effect acquires another theoretical form, as usual, in the case of remote galaxies, because it is impossible to distinguish between gravitator and lensing image.  相似文献   

3.
An exact solution of Einstein's equation is stated in which the density (), pressure (p), scale factorS and metric coefficients are functions of only one dimensionless self-similar variable,ct/R, wheret is cosmic time andR is a co-moving radial coordinate. The solution represents a cosmology that begins as a static sphere having R –2 and evolves into an expanding model which is pressure-free and has a hierarchical type of density law ( R –, approximately, with =a number, 02). It is suggested that this model should supersede the previous models of Wesson and other workers, since it appears to be the simplest cosmology for a hierarchy.  相似文献   

4.
Eselevich  V.G.  Fainshtein  V.G.  Eselevich  M.V. 《Solar physics》2001,200(1-2):259-281
A technique is proposed for separating the rays of the streamer belt with quasi-stationary and non-stationary solar wind (SW) flows. It is shown that the lifetime of rays with a quasi-stationary SW can exceed 20 days. A new method has been developed for measuring the relative density distribution of a quasi-stationary slow SW flowing along the streamer belt's ray of increased brightness, based on the LASCO/SOHO data. It is shown that the density n for such SW flows varies with the radius R according to the relationship nR –, where =13.3–3.9 within 4 R 0 R 6 R 0 (here R 0 is the solar radius), and decreases gradually further away. It is also shown that the V(R)-profiles in some rays of the streamer belt differ little from each other, although the value of the mass flow density, j E, at the Earth's orbit in them can vary more than by a factor of 4. This distinguishes in a crucial respect a slow SW in the streamer belt's rays from a fast SW originating in coronal holes, for which j Econstant and the dependences V(R) in different fast flows can differ greatly.  相似文献   

5.
We use the generalized Brans-Dicke theory, in which the Pauli metric is identified to be the physical space-time metric, to study the Universe in different epochs. Exact analytical expressions for dilaton field , cosmological radiusR and density parameter are obtained fork=+1,0,–1 Universe in the radiation-dominated epoch. For matter dominated Epoch, exact analytical expressions for Hubble parameterH, cosmological radius, dilaton field, deceleration factorq, density parameter and the gravitational coupling of the ordinary matter are obtained for the flat Universe. Other important results are: (1) the density parameter is always less than unity for the flat Universe because the dilaton field plays a role as an effective dark matter, and (2) the new Brans-Dicke parameter must be larger than 31.75 in order to consistent with the observed data.  相似文献   

6.
A three-component fluid model of the Universe during the recombination era is analysed for = c ( c is the critical density). In addition to the well-known instability of the Jeans mode at 109 M , we find two more unstable modes at 1012 M .  相似文献   

7.
It is shown that in the radiation era of the Universe spatial temperature fluctuations (T/T)<10–5 in the cosmic plasma lead to huge changes of the density up to (/)104. This effect results from the fact that the cosmic plasma in the radiation era can be considered as a general relativistic Boltzmann gas which is found in the very vincinity of equilibrium.  相似文献   

8.
Low-frequency gravitational radiation, with wavelengths reaching or exceeding interplanetary distances, and with a mean energy density of the order of the critical cosmological density c , generates a frequency-shift of order/10–15 h 0(1/108km)(/ c )1/2 in electromagnetic signals transponded by interplanetary spacecraft at a distancel from the Earth.  相似文献   

9.
In addition to our previous paper (Dehnen and Obregón, 1971) the exact cosmological solutions of Brans and Dicke's scalar-tensor theory allowing a power law between the gravitational constant and the radius of curvatureR of the universe are sought in case that — in contrast to our previous paper — the initial conditionR(t=0)=0 is avoided. There exist two different types of solutions especially for the closed space of positive curvature and for positive values of the freely available parameter of the scalar-tensor theory. The radius of curvature and also the gravitational constant increase at first with respect to time and decrease after reaching a maximum value, in contradiction to Dirac's hypothesis whereafter the gravitational constant should decrease with time in an expanding universe. The age of the universe following from these solutions is in accordance with the observations.  相似文献   

10.
There is a brightening effect of quasar outputs due to the positive curvature of space in the static Universe, if we use the right expression of distance as an arc3r=R , and not the corrected luminosity distance ofr=Rsin.  相似文献   

11.
The brightness distribution of the quiet Sun at 8.6 mm wavelength is synthesized from off-meridian observations using an eight element east-west interferometer with a maximum base line of 16.38 m (1913). The observed brightness distribution is practically flat from the disk center to the optical limb. The effective radius of the nearly uniform component is 1.01 R . If the limb brightening is present, the brightening located between 0.95 R and 1.01 R , and the total flux density of the limb brightening is less than 1% of the total flux density of the Sun. In addition to the nearly uniform component there exists a coronal component just outside the optical limb.  相似文献   

12.
Two spherically symmetric time-dependent Green's functions of the equation of transport for cosmic rays in the interplanetary region are derived by transform techniques. The solar wind velocity is assumed radial and of constant speedV. In the first model the radial diffusion coefficient =0 r (0 constant), and in the second solution =0= constant. The solutions are for monoenergetic, impulsive release of particles from a fixed heliocentric radius. Integration of the solutions over timet, fromt=0 tot=, gives the steady-state Green's functions obtained previously.  相似文献   

13.
The process of re-escalation of the scalar field as R 3, the energy density as R 3, and the pressurep aspR 3P, lends itself to obtain a reduced equation that represents, for a wide variety of equations of state, the cosmological evolution of an homogeneous and isotropic, flat Universe. A particular solution to this equation is presented.  相似文献   

14.
By use of the dispersion equation given by Song, Wu, and Dryer (1987) for a cylinder plasma with mass motion and gravity included, we investigate the linear current instabilities developed in loop prominences. The results indicate that the mode of linear instability depends mainly on whetherv s 2 > or not, wherev s is the sonic velocity at heightz, =GM/(R +z) is the gravity potential,G the gravitational constant,M andR the mass and the radius of the Sun respectively. Ifv s 2 > , then the sausage instability will be dominant. Otherwise, the kink instability will be more important. A possible explanation of knot structure, which appears sometimes in solar loop prominences has been given.  相似文献   

15.
The asymptotic properties of a turbulent disk dynamo at large dimensionless numbersR andR characterizing the helicity and the differential rotation are analysed. Three types of generations in the dependence of the relations betweenR andR are found: 2-dynamo and two types of -dynamo. For each of these types the rates of growth are obtained and the forms of solution are pointed out. Boundaries of the disk dynamo approximation are given.  相似文献   

16.
A direct approach of the dynamical equation for the evolution of the two-point density correlation function is given in an expanding flat Friedmann Universe in the Newtonian approximation. If the third and higher moments are neglected, a wave-like equation of third-order for the two-point density correlation function is found. The exact solution of this equation shows, in the large time limit, the usual Jeans instability t 4/3. It is suggested that the highern-point correlation function of the density grow liket 2n/3 in the same approximation. This indicates that every truncation procedure of the hierarchy of the equations is inapplicable at least for large timest.  相似文献   

17.
According to the classical theory of equilibrium figures surfaces of equal density, potential and pressure concur (let call them isobars). Isobars may be represented by means of Liapunov power series in small parameter q, up to the first approximation coincident with centrifugal to gravitational force ratio on the equator. A. M. Liapunov has proved the existence of the universal convergence radius q : above mentioned series converge for all bodies if q < q . Using Liapunov's algorithm and symbolic calculus tools we have calculated q = 0.000370916. Evidently, convergence radius q 0 may be much greater in non-pathological situations. We plan to examine several simplest cases. In the present paper, we find q 0 for homogeneous liquid. The convergence radius turns out to be unexpectedly large coinciding with the upper boundary value q 0 = 0.337 for Maclaurin ellipsoids.  相似文献   

18.
Starting from the field equationS =(T -A(T)), presented in a former paper, we present a test result, based on numerical simulations, giving a new model applied to the very large structure of the Universe. A theory of inverse gravitational lensing is developed, in which the observed effects could be due mainly to the action of surrounding antipodal matter. This is an alternative to the explanation based on dark matter existence. We then develop a cosmological model. Because of the hypothesis of homogeneity, the metric must be a solution of the equationS = 0, although the total mass of the Universe is non-zero. In order to avoid the trivial solutionR = constant ×t, we consider a model with variable constants. Then we derive the laws linking the different constants of physics:G, c, h, m; in order to keep the basic equations of physics invariant, so that the variation of these constants is not measurable in the laboratory, the only effect of this process being the red shift, due to the secular variation of these constants. All the energies are conserved, but not the masses. We find that all of the characteristic lengths (Schwarzschild, Jeans, Compton, Planck) vary like the characteristic lengthR, from where all the characteristic times vary like the cosmic timet. As the energy of the photonh is conserved over its flight, the decrease of its frequency is due to the growth of the Planck constanth t. In such conditions the field equations have a single solution, corresponding to a negative curvature and to an evolution law:R t 2/3.The model is no longer isentropic ands logt. The cosmologic horizon varies likeR, so that the homogeneity of the Universe is ensured at any time which constitues an alternative to the theory of inflation. We re-find, for moderate distances, Hubble's law. A new law: distance =f(z) is derived, very close to the classical one for moderate red shifts.  相似文献   

19.
Einstein's equations of general relativity are solved in terms of gravitational potential derivatives, withT equal to mass and/or field energy such thatT 0 outside a body. The line element equation then describes the variance of test particle internal geometrical structure and time-rate due to work done in a field, not the space-time curvature. Specific properties of gravitational fields and bodies come from this new solution: (a) The gravitational field consists of electromagnetic spin 2 gravitons which produce the gravitational force through the magnetic vector. (b) The gravitational mass is the Newtonian mass, not the relativistic mass, of a moving body. (c) An action principle exists in gravitation theory. (d) Attractive gravity exists between matter and antimatter. (e) Unification with quantum physics appears possible.  相似文献   

20.
Analytic structure of high-density steady isothermal spheres is discussed using the TOV equation of hydrostatic equilibrium which satisfies an equation of state of the kind:P = K g , = g c 2.Approximate analytical solutions to the Tolman-Oppenheimer-Volkoff (TOV) equations of hydrostatic equilibrium in (, ), (,U) and (u, v) phase planes in concise and simple form useful for short computer programmes or on small calculator, have been given. In Figures 1, 2, and 3, respectively, we display the qualitative behaviours of the ratio of gas density g to the central density gc , g / gc ; pressureP to the gc ,P/ gc ; and the metric componente –, for three representative general relativistic (GR) isothermal configurations =0.1, 0.2, and 0.3. Figure 4 shows the solution curve (, ) for =0.1, 0.2, and 0.3 (=0 represents the classical (Newtonian) curve). Numerical values of physical quantitiesv (=4r 2 P *(r)), in steps ofu (=M(r)/r)=0.03, and the mass functionU, in steps of =0.2 (dimensionless radial distance), are given, respectively, in Tables I and II. Other interesting features of the configurations, such as ratio of gravitational radius 2GM/c 2 to the coordinate radiusR, mass distributionM(r)/M, pressure (or density) distributionP/P c , binding energy (B.E.), etc., have also been incorporated in the text. It has further been shown that velocity of sound inside the configurations is always less than the velocity of light.Part of the work done at Azerbaijan State University, Baku, U.S.S.R., and Mosul University, Mosul, Iraq, 1985-1986  相似文献   

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