This is one of the corner-stones of the Hot Big Bang model.

N2 - Big bang nucleosynthesis (BBN) describes the production of the lightest nuclides via a dynamic interplay among the four fundamental forces during the first seconds of cosmic time. A brief overview of the essentials of this physics is given, and new calculations presented of light-element abundances through Li6 and Li7, with updated nuclear reactions and uncertainties including those in the neutron lifetime. Fits are provided for these results as a function of baryon density and of the number of neutrino flavors Nν. Recent developments are reviewed in BBN, particularly new, precision Planck cosmic microwave background (CMB) measurements that now probe the baryon density, helium content, and the effective number of degrees of freedom Neff. These measurements allow for a tight test of BBN and cosmology using CMB data alone. Our likelihood analysis convolves the 2015 Planck data chains with our BBN output and observational data. Adding astronomical measurements of light elements strengthens the power of BBN. A new determination of the primordial helium abundance is included in our likelihood analysis. New D/H observations are now more precise than the corresponding theoretical predictions and are consistent with the standard model and the Planck baryon density. Moreover, D/H now provides a tight measurement of Nν when combined with the CMB baryon density and provides a 2σ upper limit Nν

The neutron lifetime can be well approximated by

This process is called nucleosynthesis.Its harder and harder to make nuclei with higher masses.

Big Bang nucleosynthesis - Wikipedia

But, as matter condenses out of the cooling Universe, a morestable epoch is entered, one where the slow, gentle force of gravitydominates over the nuclear forces of earlier times.Much of the hydrogen that was created at recombination was used up inthe formation of galaxies, and converted into stars.

Big Bang Nucleosynthesis - UC Berkeley Astronomy w

gravity), so this time, and until today, is called thematter era.Today, radiation in the form of photons have a very passiverole in the evolution of the Universe.

The higher the density, the morehelium produced during the nucleosynthesis era.
At this temperature, nucleosynthesis, or the production of light elements, could take place.

Big Bang nucleosynthesis - ScienceDaily

Big bang nucleosynthesis (BBN) describes the production of the lightest nuclides via a dynamic interplay among the four fundamental forces during the first seconds of cosmic time. A brief overview of the essentials of this physics is given, and new calculations presented of light-element abundances through Li6 and Li7, with updated nuclear reactions and uncertainties including those in the neutron lifetime. Fits are provided for these results as a function of baryon density and of the number of neutrino flavors Nν. Recent developments are reviewed in BBN, particularly new, precision Planck cosmic microwave background (CMB) measurements that now probe the baryon density, helium content, and the effective number of degrees of freedom Neff. These measurements allow for a tight test of BBN and cosmology using CMB data alone. Our likelihood analysis convolves the 2015 Planck data chains with our BBN output and observational data. Adding astronomical measurements of light elements strengthens the power of BBN. A new determination of the primordial helium abundance is included in our likelihood analysis. New D/H observations are now more precise than the corresponding theoretical predictions and are consistent with the standard model and the Planck baryon density. Moreover, D/H now provides a tight measurement of Nν when combined with the CMB baryon density and provides a 2σ upper limit Nν

The s-processworks as long as the decay time for unstable isotopes is longer than thecapture time.

Is "Big Bang Theory" Bad for Science? - Science Not Fiction

The smoking gun for evidence of the Big Bang is the cosmic microwave backgroundradiation (CMB), the relic of the early universe when the matter wasdecoupling from light. This forms the next focus of the course,starting with its discovery, determination of its blackbody form,dipolar anisotropy as evidence of the peculiar motion of the solarsystem, and the full-blown power spectrum of angular fluctuations asdetermined recently by the WMAP experiment. Its existence rules againststeady-state universes, and its dappled appearance in sky maps () signalsthe onset of structure formation in the universe. Accordingly, thisrich physical manifestation of the universe dating from over 13 billionyears ago has garnered two Nobel Prizes in physics.

Up to this time (just over three minutes past the Beginning) there had been no nucleosynthesis.

18/12/2017 · Timeline of the Big Bang Theory


Apart from Hydrogen and Helium which are the products of all observed chemical elements heavier that Helium (C, O, … called metals by astronomers) are synthesised inside stars. Stellar nucleosynthesis provides clues not only to stellar evolution but also to space-time distribution of matter in the universe. A probe to nucleosynthesis in our Galaxy is given by the chemical abundances in the solar system which testify for their abundance at the time of formation of the solar system. Evidence of nucleosynthesis in other stars has been discovered in S-Type stars by Merrill (1952). Population II stars are poor in metals whereas Population I are 2 orders of magnitude richer.