Related papers: Big Bang: a theory or fact
A review of Big Bang Nucleosynthesis (BBN) is presented. Observations of deuterium and helium-4 are discussed. Some BBN restrictions on non-standard physics, especially on neutrino properties and time-variation of fundamental constants are…
The big bang model and the history of the early universe according to the grand unified theories are introduced. The shortcomings of big bang are discussed together with their resolution by inflationary cosmology. Inflation, the subsequent…
Astrophysical nucleosynthesis is a family of diverse processes by which atomic nuclei undergo nuclear reactions and decays to form new nuclei. The complex nature of nucleosynthesis, which can involve as many as tens of thousands of…
In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of…
We observe photons and neutrinos from stars. Based on these observations, complemented by measurements of cosmic rays energies and composition, we have been able to constrain several models for the Big Bang and for stellar evolution. But…
Research over the past 25 years has led to the view that the rich tapestry of present-day cosmic structure arose during the first instants of creation, where weak ripples were imposed on the otherwise uniform and rapidly expanding…
Measurements of the primordial element abundances provide us with an important probe of our universe's early thermal history, allowing us to constrain the expansion rate and composition of our universe as early as $\sim 1 \, {\rm s}$ after…
The `Little Bangs' made in particle collider experiments reproduce the conditions in the Big Bang when the age of the Universe was a fraction of a second. It is thought that matter was generated, the structures in the Universe were formed…
The nature of the first generation of stars in the Universe remains largely unknown. Observations imply the existence of massive primordial stars early in the history of the universe, and the standard theory for the growth of cosmic…
Our universe was born about 13.8 billion years ago from an extremely hot and dense singular point, in a process known as the Big Bang. The hot and dense matter which dominated the system within a few microseconds of its birth was in the…
From an observational perspective cosmology is today in excellent shape - advances in instrumentation and data processing have enabled us to study the universe in detail back to when the first galaxies formed, map the fluctuations in the…
Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the…
The predictions of Standard Big Bang Nucleosynthesis are summarized and compared with observations of abundances of helium in HII regions, deuterium in quasar absorbers, deuterium and helium-3 in the Galaxy, and lithium in metal-poor stars.…
The continuity equation requires that energy released in nuclear fusion flows away from the point of interaction and is not immediately thermalised into the CMB. It is seen that consequently the bulk of thermo-nuclear energy released in BBN…
Primordial or Big Bang nucleosynthesis (BBN) is one of the three strong evidences for the Big- Bang model together with the expansion of the Universe and the Cosmic Microwave Background radiation. In this study, we improve the standard BBN…
Our understanding of the observed elemental abundance in the universe, stemming from nuclear reactions during the big bang or from nucleosynthesis within stellar environments, requires theoretical analyses based on multidimensional…
This essay is a nontechnical primer for a broader audience, in which I paint a broad-brush picture of modern cosmology. I begin by reviewing the evidence for the big bang, including the expansion of our Universe, the cosmic microwave…
First, this paper broaches the definition of science and the epistemic yield of tenets and approaches: phenomenological (descriptive only), well-founded (solid first principles, conducive to deep understanding), provisional (falsifiable if…
We perform calculations of dark photon production and decay in the early universe for ranges of dark photon masses and vacuum coupling with standard model photons. Simultaneously and self-consistently with dark photon production and decay,…
We study effects of long-lived massive particles, which decay during the big-bang nucleosynthesis (BBN) epoch, on the primordial abundances of light elements. Compared to the previous studies, (i) the reaction rates of the standard BBN…