[en] Observational results indicate that the Hubble flow as well as the cosmic background radiation tend to be anisotropic. In standard cosmological models such anisotropy effects are interpreted as perturbative inhomogeneities on the homogeneous Friedmannian background. The inhomogeneous nonstandard model can be at least an acceptable alternative if the inhomogeneities are considered to be the property of Tolman's background. (author). 19 refs

[en] Steady-state theories are very difficult to rule out on observational grounds, particularly if they are adjusted to contain a three-degree isotropic thermal-background radiation. However, anthropic-principle arguments can be used to rule out virtually any cosmological theory which has the universe stationary in the large. For example, anthropic considerations show that the perfect cosmological principle is self-contradictory. (author)

[en] Using Hamiltonian techniques, we study class-A Bianchi universes generated by a spinor source. We show that these cosmological models do not belong in general to the diagonal case, and derive a new solution to Einstein-Dirac equations in the type-II case

[en] A list of 556 references, covering the subject of cosmology, listed in alphabetical order by first author (A to K only), is given. (U.K.)

[en] There has been much interest in the study of the dynamical properties of type IX cosmological models. Such studies rely on the use of Kasner stages together with an associated discretization of the orbit. In this work I argue that this discretization is essentially 1-dimensional and does not yield a complete specification of the pair of momentum variables. I show that a consistent approximation, with the correct number of parameters, can be extracted from the dynamics of separatrix transitions. In this context it is stressed that the discretization fails to describe essential properties of this class os models. (author)

[en] Possible methods of detecting other planetary systems are examined, in the light of available data. It is concluded that it is still uncertain whether such systems exist. It is certain that no information is available which will allow us to clarify our understanding of the main characteristics of planetary systems. Some probable and some possible examples are discussed. (U.K.)

No abstract available

[en] Published in summary form only

[en] The status of the inflationary model of the very early universe is summarized. In this model the universe supercools many orders of magnitude below the critical temperature of a grand unified theory phase transition, and in the process it expands by many orders of magnitude. The model can solve the monopole, horizon, and flatness problems of the standard hot big-bang cosmology, and at the same time it offers an explanation of the origin of all matter, energy, and entropy of the universe. There are still uncertainties concerning the mechanism which ends the inflationary era, but the new ending proposed by Linde and by Albrecht and Steinhardt appears very promising

[en] I comment on a recent paper of Nagao and in particular give a proof that a special type of homology basis used by Nagao and previous workers is not admitted by the complex double of any unorientable surface with a boundary. However, their final results are not invalidated by the modifications required by the use of a less restricted class of homology bases