Big Bang nucleosynthesis: In physical cosmology, Big Bang nucleosynthesis (or primordial nucleosynthesis) refers to the production of nuclei other than H-1, the normal, light hydrogen, during the early phases of the universe, shortly after the Big Bang. Synthesis of the naturally occurring elements and their isotopes present in the Solar System solids may be divided into three broad segments: primordial nucleosynthesis (H, He), energetic particle (cosmic ray) interactions (Li, Be, B), and stellar nucleosynthesis (C and heavier elements).
The image illustrates two of the nuclear reactions occurring during Big Bang Nucleosynthesis: It shows protons and neutrons combining to form deuterium nuclei (D, containing one proton and one neutron), accompanied by the emission of high energy photons (denoted as γ); furthermore, it shows two deuterium nuclei fusing.
During the formation of the universe some 14 billion years ago in the so-called ‘Big Bang’, only the lightest elements were formed, hydrogen and helium along with trace amounts of lithium and beryllium. Light elements (namely deuterium, helium, and lithium) were produced in the first few minutes of the Big Bang, while elements heavier than helium are thought to have their origins in the interiors of stars which formed much later in the history of the Universe.
Big bang nucleosynthesis was the creation of elements heavier than hydrogen, mainly helium. After the Big Bang, there were only protons and neutrons. … Shortly after the big bang temperatures and pressures were high enough the create helium and traces of lithium and beryllium by fusion.
The era of nucleosynthesis is important because during this time all the primordial hydrogen and helium were created from the nuclear fusion process. Except for the few percent of matter that stars later fused into heavier elements, the chemical composition of the universe remains unchanged today.
Instead of extrapolating “hot and dense” back to an infinitely hot, infinitely dense singularity, inflation basically says that the hot Big Bang was preceded by a period where an extremely large energy density was present in the fabric of space itself, causing the Universe to explode and inflate.
Five Dark Matter Facts:
1st: The total amount of normal matter in the Universe is unambiguously known.
2nd: You cannot explain either the cosmic microwave background or the large-scale structure of the Universe without dark matter.
3rd: Dark matter behaves as a particle, and that’s fundamentally special compared to something that behaves as a field.
4th: Very real small-scale physics effects, like dynamical heating, star-formation and feedback, and nonlinear effects must be worked out.
5th: You must explain the full suite of cosmological evidence, or you’re cherry-picking, not doing legitimate science.
