scholarly journals Primordial nucleosynthesis: A cosmological probe

2009 ◽  
Vol 5 (S268) ◽  
pp. 19-26
Author(s):  
Gary Steigman

AbstractDuring its early evolution the Universe provided a laboratory to probe fundamental physics at high energies. Relics from those early epochs, such as the light elements synthesized during primordial nucleosynthesis when the Universe was only a few minutes old, and the cosmic background photons, last scattered when the protons (and alphas) and electrons (re)combined some 400 thousand years later, may be used to probe the standard models of cosmology and of particle physics. The internal consistency of primordial nucleosynthesis is tested by comparing the predicted and observed abundances of the light elements, and the consistency of the standard models is explored by comparing the values of the cosmological parameters inferred from primordial nucleosynthesis with those determined by studying the cosmic background radiation.

2006 ◽  
Vol 15 (01) ◽  
pp. 1-35 ◽  
Author(s):  
GARY STEIGMAN

Primordial nucleosynthesis provides a probe of the Universe during its early evolution. Given the progress exploring the constituents, structure, and recent evolution of the Universe, it is timely to review the status of Big Bang Nucleosynthesis (BBN) and to confront its predictions, and the constraints which emerge from them, with those derived from independent observations of the Universe at much later epochs in its evolution. Following an overview of the key physics controlling element synthesis in the early Universe, the predictions of the standard models of cosmology and particle physics (SBBN) are presented, along with those from some non-standard models. The observational data used to infer the primordial abundances are described, with an emphasis on the distinction between precision and accuracy. These relic abundances are compared with predictions, testing the internal consistency of BBN and enabling a comparison of the BBN constraints with those derived from the WMAP Cosmic Background Radiation data. Emerging from these comparisons is a successful standard model along with constraints on (or hints of) physics beyond the standard models of particle physics and of cosmology.


2009 ◽  
Vol 5 (S265) ◽  
pp. 15-22 ◽  
Author(s):  
Gary Steigman

AbstractDuring its early evolution, the hot, dense Universe provided a laboratory for probing fundamental physics at high energies. By studying the relics from those early epochs, such as the light elements synthesized during primordial nucleosynthesis when the Universe was only a few minutes old, and the relic, cosmic microwave photons, last scattered when the protons, alphas, and electrons (re)combined some 400 thousand years later, the evolution of the Universe may be used to test the standard models of cosmology and particle physics and to set constraints on proposals of physics beyond these standard models.


1994 ◽  
Vol 2 (2) ◽  
pp. 155-164
Author(s):  
Martin J. Rees

During the last 25 years, evidence has accumulated that our universe has evolved, over a period of 10–15 billion years, from a hot dense fireball to its present state. Telescopes can detect objects so far away that the universe had only a tenth its present age when the light we now receive set out towards us. The cosmic background radiation, and the abundances of elements such as helium and lithium, permit quantitative inferences about what the universe was like when it had been expanding for only a few seconds. The laws of physics established in the laboratory apparently suffice for interpreting all astronomical phenomena back to that time. In the initial instants of cosmic expansion, however, the particle energies and densities were so extreme that terrestrial experiments offer no firm guidance. We will not understand why the universe contains the observed ‘mix’ of matter and radiation, nor why it is expanding in the observed fashion, without further progress in fundamental physics.


1993 ◽  
Vol 02 (01) ◽  
pp. 97-104 ◽  
Author(s):  
V.G. GURZADYAN ◽  
A.A. KOCHARYAN

The anisotropy properties of the Cosmic Microwave Background Radiation (CMB) are considered within the framework of the photon beam mixing effect developed earlier. The existence of an observable characteristic of the CMB is shown, namely the geometrical shape of anisotropy spots and their degree of complexity, which can contain unique information on cosmological parameters and the life history of the Universe. If future experiments (COBE and others) indicate such features of anisotropy maps, then one can have serious evidence for the negative curvature of the Universe.


1988 ◽  
Vol 20 (1) ◽  
pp. 658-660
Author(s):  
J. Audouze

Primordial nucleosynthesis which is responsible for the formation of the lightest elements (D, 3He, 4HE and 7Li) might be as important as the overall expansion of the Universe and the cosmic background radiation to prove the occurrence of a dense and hot phase for the Unvierse about 15 billion years ago. As recalled in many reviews (e.g. refs. 1, 2) the standard Big Bang nucleosynthesis leads to two important conclusions regarding (i) a limitation of the baryonic density such that the corresponding cosmological parameter ΩB ≤ 0.1; (ii) a limitation of the number of neutrino flavours to 3-4 consistent with the results concerning the widths of the Z0 and W± particles3.


1996 ◽  
Vol 11 (19) ◽  
pp. 1531-1538 ◽  
Author(s):  
LI-ZHI FANG ◽  
YI-PENG JING

According to causality, the existence of density perturbations on scales larger than the present Hubble radius y = 2c/H0 is crucial to discriminate between inflation and non-inflation models of the origin of inhomogeneity of the universe. Observations of the cosmic background radiation anisotropies favor a super-Hubble suppression on scales λmax in the range 0.5–3.0y. Many of non-inflation models are consistent with such a suppression. Inflation models are certainly not in conflict with this suppression, however one important parameter, the duration of the epoch of inflation, may need to be fine tuned.


2007 ◽  
Vol 3 (T26B) ◽  
pp. 179-180
Author(s):  
Francesco Bertola ◽  
Sadanori Okamura ◽  
Virginia L. Trimble ◽  
Mark Birkinshaw ◽  
Françoise Combes ◽  
...  

Division VIII gathers astronomers engaged in the study of the visible and invisible matter in the Universe at large, from Local Group galaxies via distant galaxies and galaxy clusters to the large-scale structure of the Universe and the cosmic background radiation.


1993 ◽  
Vol 08 (28) ◽  
pp. 2615-2621 ◽  
Author(s):  
LI-ZHI FANG

A few years ago, we proposed that the spatial topology of the universe can be detected by cosmic background radiation (CBR), because the amplitudes of the spherical harmonic expansion of CBR anisotropy are sensitively dependent on the size of the universe. Recently, this method has been applied to study the size of a T3 universe by using the COBE-DMR data of CBR temperature fluctuation. The new result of the lower limit to the cosmologically spatial size is found to be larger than the old values by a factor of about 5. Therefore, the model of cubic T3 small universe can be ruled out. This paper is a summary of this progress. The significance and remained problems of the spatial topology of the universe have also been discussed.


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