# Alternative ideas in cosmology

TL;DR: Some remarkable examples of alternative cosmological theories are reviewed here, ranging from a compilation of variations on the Standard Model through the more distant quasi-steady-state cosmology, plasma cosmology or universe models as a hypersphere, to the most exotic cases including static models as discussed by the authors .

Abstract: Some remarkable examples of alternative cosmological theories are reviewed here, ranging from a compilation of variations on the Standard Model through the more distant quasi-steady-state cosmology, plasma cosmology, or universe models as a hypersphere, to the most exotic cases including static models. The present-day Standard Model of cosmology, [Formula: see text]CDM, gives us a representation of a cosmos whose dynamics is dominated by gravity (Friedmann equations derived from general relativity) with a finite lifetime, large scale homogeneity, expansion and a hot initial state, together with other elements necessary to avoid certain inconsistencies with observations (inflation, nonbaryonic dark matter, dark energy, etc.). There are however some models with characteristics that are close to those of the Standard Model but differing in some minor aspects; we call these “variations on the Standard Model”. Many of these models are indeed investigated by some mainstream cosmologists: different considerations on CP violation, inflation, number of neutrino species, quark-hadron phase transition, baryonic or nonbaryonic dark-matter, dark energy, nucleosynthesis scenarios, large-scale structure formation scenarios; or major variations like a inhomogeneous universe, Cold Big Bang, varying physical constants or gravity law, zero-active mass (also called “[Formula: see text]”), Milne, and cyclical models. At the most extreme distance from the Standard Model, the static models, a noncosmological redshift includes “tired-light” hypotheses, which assume that the photon loses energy owing to an intrinsic property or an interaction with matter or light as it travels some distance, or other nonstandard ideas. Our impression is that none of the alternative models has acquired the same level of development as [Formula: see text]CDM in offering explanations of available cosmological observations. One should not, however, judge any theory in terms of the number of observations that it can successfully explain (ad hoc in many cases) given the much lower level of development of the alternative ones, but by the plausibility of its principles and its potential to fit data with future improvements of the theories. A pluralist approach to cosmology is a reasonable option when the preferred theory is still under discussion.

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TL;DR: In this article , the authors compare the results of the standard ΛCDM cosmological model and some static cosmology models, including Zwicky's "tired-light" model.

Abstract: The James Webb Space Telescope (JWST), which has recently become operational, is capable of detecting objects at record-breaking redshifts, z≳15. This is a crucial advance for observational cosmology, as at these redshifts the differences between alternative cosmological models manifest themselves in the most obvious way. In recent years, some observational hints have emerged indicating that the Standard Cosmological Model could require correcting. One of these hints is related to the discovery of remote galaxies whose redshifts correspond to the very young Universe (less than one billion years after the Big Bang) but which are similar to nearby galaxies. The issue is that such galaxies in the early Universe do not have enough time to evolve into something similar to the late-Universe galaxies. JWST observations of high-redshift objects are expected to shed light on the origin of this issue. Here we provide results on performing the “angular diameter—redshift” cosmological test for the first JWST observation data. We compare this result with predictions of the standard ΛCDM cosmological model and some static cosmological models, including Zwicky’s “tired-light” model. The latter is currently assumed to be ruled out by observations. We challenge this assumption and show that a static model can provide a natural and straightforward way of solving the puzzle of the well-evolved galaxies and better agreements with the results of the JWST “angular diameter—redshift” test at high redshifts than the correcting evolution model within the ΛCDM framework. We discuss several cosmological tests that will be important for further research on the possibility of revising the expanding Universe paradigm.

1 citations

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TL;DR: In this paper , a comprehensive survival strategy based on ectogenesis, the raising of embryos in artificial uterus systems, was proposed to ensure human survival and procreativity on future Earths.

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01 Jan 2011

TL;DR: The Cycle of Time as mentioned in this paper provides a new perspective on cosmology, providing a quite unexpected answer to the often-asked question "what came before the Big Bang?" The two key ideas underlying this novel proposal are a penetrating analysis the Second Law of thermodynamics - according to which the randomness of our world is continually increasing - and a thorough examination of the light-cone geometry of space-time.

Abstract: Roger Penrose's groundbreaking and bestselling "The Road to Reality" provided a comprehensive yet readable guide to our present understanding of the laws that are currently believed to govern our universe. In "Cycles of Time", he moves far beyond this to develop a completely new perspective on cosmology, providing a quite unexpected answer to the often-asked question, 'what came before the Big Bang'? The two key ideas underlying this novel proposal are a penetrating analysis the Second Law of thermodynamics - according to which the 'randomness' of our world is continually increasing - and a thorough examination of the light-cone geometry of space-time. Penrose is able to combine these two central themes to show how the expected ultimate fate of our accelerating, expanding universe can actually be reinterpreted as the 'Big Bang' of a new one. On the way, many other basic ingredients are presented, and their roles discussed in detail, though without any complex mathematical formulae (these all being banished to the appendices). Various standard and non-standard cosmological models are presented, as is the fundamental and ubiquitous role of the cosmic microwave background. Also crucial to the discussion are the huge black holes lying in galactic centres, and their eventual disappearance via the mysterious process of Hawking evaporation.

296 citations

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TL;DR: An introductory account of the inflationary cosmology is given in this paper, which postulates a period of accelerated expansion during the Universe's earliest stages and provides a possible model for the origin of structure in the Universe, and key results are reviewed along with a discussion of the current observational situation and outlook.

Abstract: An introductory account is given of the inflationary cosmology, which postulates a period of accelerated expansion during the Universe's earliest stages. The historical motivation is briefly outlined, and the modelling of the inflationary epoch explained. The most important aspect of inflation is that it provides a possible model for the origin of structure in the Universe, and key results are reviewed, along with a discussion of the current observational situation and outlook.

90 citations

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TL;DR: Stickland as mentioned in this paper reported on progress in physics Vol 20 (1957) Pp iv + 568 Vol 21 (1958) pp iv+ 383 Edited by A C Stickland (London: The Physical Society, 1957, 1958) Each 63s net

Abstract: Reports on Progress in Physics Vol 20 (1957) Pp iv + 568 Vol 21 (1958) Pp iv + 383 Edited by A C Stickland (London: The Physical Society, 1957, 1958) Each 63s net

85 citations

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TL;DR: In this paper, the field gravity fractal cosmological model (FGF) is presented, which is based on two initial principles: the first assumption is that the Feynman's field gravity approach describes the gravitational interaction, which delivers a natural basis for the conceptual unity of all fundamental physical interactions within the framework of the relativistic and quantum fields in Minkowski space.

Abstract: The idea of the global gravitational effect as the source of cosmological redshift was considered by de Sitter (1916, 1917), Eddington (1923), Tolman (1929) and Bondi (1947). Also Hubble (1929) called the discovered distance-redshift relation as "De Sitter effect". For homogeneous matter distribution cosmological gravitational redshift is proportional to square of distance: z_grav ~ r^2. However for a fractal matter distribution having the fractal dimension D=2 the global gravitational redshift is the linear function of distance: z_grav ~ r, which gives possibility for interpretation of the Hubble law without the space expansion. Here the field gravity fractal cosmological model (FGF) is presented, which based on two initial principles. The first assumption is that the Feynman's field gravity approach describes the gravitational interaction, which delivers a natural basis for the conceptual unity of all fundamental physical interactions within the framework of the relativistic and quantum fields in Minkowski space. The second hypothesis is that the spatial distribution of gravitating matter is a fractal at all scales up to the Hubble radius. The fractal dimension of matter distribution is assumed to be D = 2, which implies that the global gravitational redshift is the explanation of the observed linear Hubble law. In the frame of the FGF all three phenomena - the cosmic background radiation, the fractal large scale structure, and the Hubble law, - could be the consequence of a unique large scale structure evolution process of the initially homogeneous ordinary matter without nonbaryonic matter and dark energy.

22 citations