ترغب بنشر مسار تعليمي؟ اضغط هنا

Einsteins static universe

34   0   0.0 ( 0 )
 نشر من قبل Domingos Soares
 تاريخ النشر 2012
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Domingos Soares




اسأل ChatGPT حول البحث

Einsteins static model is the first relativistic cosmological model. The model is static, finite and of spherical spatial symmetry. I use the solution of Einsteins field equations in a homogeneous and isotropic universe -- Friedmanns equation -- to calculate the radius of curvature of the model (also known as Einsteins universe). Furthermore, I show, using a Newtonian analogy, the models mostly known feature, namely, its instability under small perturbations on the state of equilibrium.

قيم البحث

اقرأ أيضاً

We consider a cosmology in which the final stage of the Universe is neither accelerating nor decelerating, but approaches an asymptotic state where the scale factor becomes a constant value. In order to achieve this, we first bring in a scale factor with the desired property and then determine the details of the energy contents as a result of the cosmological evolution equations. We show that such a scenario can be realized if we introduce a generalized quintom model which consists of a scalar field and a phantom with a {it negative} cosmological constant term. The standard cold dark matter with $w_m=0$ is also introduced. This is possible basically due to the balance between the matter and the {it negative} cosmological constant which tend to attract and scalar field and phantom which repel in the asymptotic region. The stability analysis shows that this asymptotic solution is classically stable.
38 - L. G. Medeiros 2012
This work presents a complete cyclic cosmological scenario based on nonlinear magnetic field. It is constructed a model composed by five fluids namely baryonic matter, dark matter, radiation, neutrinos and a cosmological magnetic field. The first fou r fluids are treated in the standard way and the fifth fluid, the magnetic field, is described by a nonlinear electrodynamics. The free parameters are fitted by observational data (SNIa, CMB, extragalactic magnetic fields, etc) and by simple theoretical considerations. As result arises a cyclic cosmological model which preserves the main successes of standard big bang model and solve some other problems like the initial singularity, the present acceleration and the Big Rip.
76 - John G. Hartnett 2011
The Hubble law, determined from the distance modulii and redshifts of galaxies, for the past 80 years, has been used as strong evidence for an expanding universe. This claim is reviewed in light of the claimed lack of necessary evidence for time dila tion in quasar and gamma-ray burst luminosity variations and other lines of evidence. It is concluded that the observations could be used to describe either a static universe (where the Hubble law results from some as-yet-unknown mechanism) or an expanding universe described by the standard Lambda cold dark matter model. In the latter case, size evolution of galaxies is necessary for agreement with observations. Yet the simple non-expanding Euclidean universe fits most data with the least number of assumptions. From this review it is apparent that there are still many unanswered questions in cosmology and the title question of this paper is still far from being answered.
55 - Daegene Song 2015
In this paper, we discuss that an observable-based single-system Copenhagen and entanglement-based two-system von Neumann measurement protocols in quantum theory can be made equivalent by considering the second part of the two-system scheme to be a D irac-type negative sea filling up the first system. Based on this equivalence, and by considering the universe as a computational process, the choice of the apparatus state in the two-system protocol can be identified with the choice of the observable in the single-system scheme as negative sea filling up the observable universe. In particular, the measuring partys state is considered to be evolving backwards in time to the big bang as a nondeterministic computational process, which chooses the acceptable path as a time-reversal process of irreversible computation. The suggested model proposes that the prepared microstate of the universe, or reality, corresponds to the observers choice, therefore, subjective reality. Thus, this effectively provides a specific description of the subjective universe model previously proposed, which is based on the symmetry breakdown between the Schrodinger and the Heisenberg pictures of quantum theory.
From the observed results of the space distribution of quasars we deduced that neutrino mass is about 10^(-1) eV. The fourth stable elementary particle (delta particle) with mass about 10^(0) eV can help explain the energy resource mechanism in quasa rs, cosmic ultra-high energy particles, as well as the flatness of spiral galaxy rotation curves. The blue bump and IR bump in the quasar irradiation spectra, as well as the peaks of EBL (Extra-galactic Background Light) around 10^(0) eV and 10^(-1) eV, are related to the annihilation of delta particle with anti-delta particle and neutrino with anti-neutrino respectively. This enlightens us to explore the reason for missing solar neutrinos and the unlimited energy resource in a new manner. For delta-particle search it is related to Dual SM or Two-fold SM; the relationship between space electron spectrum (>10^(0)Tev) and cosmic ray spectrum (knee and ankle) at high energy region; and the characteristics of spherical universe. Appendix is the theory part, which related to mass tree, inflation, BSM, finite universe.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا