6 Kosmologie

Blome, Hans Joachim; Hoell, Josef; Priester, Wolfgang

doi:10.1515/9783110221596.439

Cited by 3 publications

(3 citation statements)

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“…In the following cosmological considerations we treat the cosmic vacuum by quantities denoting its vacuum energy density ε vac and its associated vacuum pressure p vac , like done in case of a hydrodynamic fluid which in general relativity theory is described by the following fluid-type hydrodynamical energy-momentum tensor (see e.g Goenner 1996;Overduin & Fahr 2001;Blome, Hoell & Priester 2002;Fahr 2004)…”

Section: Thermodynamics Of the Cosmic Vacuummentioning

confidence: 99%

The Thermodynamics of a Gravitating Vacuum

Heyl

Zentrum²,

Scholar³

et al. 2015

PSIJ

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In the present days of modern cosmology it is assumed that the main ingredient to cosmic energy presently is vacuum energy with an energy density ǫ vac that is constant over the cosmic evolution. In this paper here we show, however, that this assumption of constant vacuum energy density is unphysical, since it conflicts with the requirements of cosmic thermodynamics. We start from the total vacuum energy including the negatively valued gravitational binding energy and show that cosmic thermodynamics then requires that the cosmic vacuum energy density can only vary with cosmic scale R = R(t) according to ǫ vac ∼ R −ν with only two values of ν being allowed, namely ν 1 = 2 and ν 2 = 5/2. We then discuss these two remaining solutions and find, when requiring a universe with a constant total energy, that the only allowed power index is ν 1 = 2. We discuss the consequences of this scaling of ǫ vac and show the results for a cosmic scale evolution of a quasi-empty universe like the one that we are presently faced by.

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Section: Thermodynamics Of the Cosmic Vacuummentioning

confidence: 99%

The Thermodynamics of a Gravitating Vacuum

Heyl

Zentrum²,

Scholar³

et al. 2015

PSIJ

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“…Then with the help of the well-known photon temperaturescale relation T ∼ (1/R) (e.g. see [8,35]) one would furthermore find for the beginning t b and the end t e of the recombination era the relation R e /R b = t e /t b yielding where the beginning of the recombination period, as usually assumed in cosmology, was timed with t b 380000 years.…”

Section: The Process Of Recombinationmentioning

confidence: 99%

The “writing on the cosmic wall”: Is there a straightforward explanation of the cosmic microwave background?

Fahr¹,

Zönnchen²

2009

Ann. Phys.

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The Cosmic Microwave Background (CMB) is taken today as reflecting the thermodynamical state of the universe at these early cosmic times. Based on this assumption and standard cosmological principles meanwhile many fundamental cosmological facts have been deduced from the CMB state which, however, to some surprise reveal that the universe should be dominated by dark energy and dark matter, while for its energy content the usual baryonic matter is nearly negligible. Thus the question which we want to raise in this article is, whether this standard interpretation of the CMB phenomenon is solid and unequivocal enough to support the standard cosmological claims. We shall show, however, that in many details the standard explanation is not straightforward, but allows for important alternatives which seriously should be looked at. Especially arguments for a vanishing cosmic curvature (k = 0) are shown to be weak, and, contrary to the usual claim, the light distance to the recombination horizon is in fact strongly model-biassed. We also show that the CMB dipole which is generally understood as a consequence of a peculiar motion by about 680 km/s with respect to rest system of the CMB can as well, and perhaps even better, be understood as indication of differerent cosmological expansion dynamics seen in an anisotropically expanding universe in different directions of the sky. We also discuss that the power amplitude (i.e. effective Planck temperature) in the dipolar CMB structure depends on wavelength even inverting the dipole maximum orientation in the Wien's branch. In addition unexpected properties of the lowest CMB multipoles could mean that we are at least partly seeing an unquantifyable foreground in the background. Only after its removal the CMB interpretation could at all then, but then on a completely new basis, become a subject of cosmological terms. At the end of this article we shall briefly discuss an alternative explanation of the CMB radiation which helps to better understand the mysterious cosmic photon-to-baryon ratio of about 10 9 .

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“…those with Λ ¼ 0) (for a review, see Friedmann 1922Friedmann , 1924, or those with Λ] 0 (see reviews given, e.g. by Goenner 1996;and Blome et al 2002) the actual Hubble constant is determined by:…”

Section: A Consistency Check With Cosmological Factsmentioning

confidence: 99%

Cosmological implications of the Machian principle

Fahr

2006

Naturwissenschaften

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The famous idea of Ernst Mach concerning the non-absolute but relational character of particle inertia is taken up in this paper and is reinvestigated with respect to its cosmological implications. From Thirring's general relativistic study of the old Newtonian problem of the relativity of rotations in different reference systems, it appears that the equivalence principle with respect to rotating reference systems, if at all, can only be extended to the system of the whole universe, if the mass of the universe scales with the effective radius or extent of the universe. A reanalysis of Thirring's derivations still reveals this astonishing result, and thus the general question must be posed: how serious this result has to be taken with respect to cosmological implications. As we will show, the equivalence principle is, in fact, fulfilled by a universe with vanishing curvature, i.e. with a curvature parameter k = 0, which just has the critical density rho (crit) = (3H)(2)/8piG, where H is the Hubble constant. It turns out, however, that this principle can only permanently be fulfilled in an evolving cosmos, if the cosmic mass density, different from its conventional behaviour, varies with the reciprocal of the squared cosmic scale. This, in fact, would automatically be realized, if the mass of each cosmic particle scales with the scale of the universe. The latter fact, on one hand, is a field-theoretical request from a general relativistic field theory which fulfills H. Weyl's requirement of a conformal scale invariance. On the other hand, it can perhaps also be concluded on purely physical grounds, when taking into account that as source of the cosmic metrics only an effective mass density can be taken. This mass density represents the bare mass density reduced by its mass equivalent of gravitational self-binding energy. Some interesting cosmological conclusions connected with this fact are pointed out in this paper.

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6 Kosmologie

Cited by 3 publications

References 0 publications

The Thermodynamics of a Gravitating Vacuum

The Thermodynamics of a Gravitating Vacuum

The “writing on the cosmic wall”: Is there a straightforward explanation of the cosmic microwave background?

Cosmological implications of the Machian principle

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