It also predicts about 0. The Big Bang theory predicts that we should be able to detect these stretched-out photons, if we look in the right part of the electromagnetic spectrum: Precision observations of the cosmic microwave background radiation   with the Wilkinson Microwave Anisotropy Probe WMAP and Planck give an independent value for the baryon-to-photon ratio.
That fusion process essentially shut down at about 20 minutes, due to drops in temperature and density as the universe continued to expand.
A beginning in time was "repugnant" to him. Further support comes from the consistency of the other light element abundances for one particular baryon density and an independent measurement of the baryon density from the anisotropies in the cosmic microwave background radiation.
In terms of the present day critical density of matter, the required density of baryons is a few percent the exact value depends on the assumed value of the Hubble constant.
For a long time, this meant that to test BBN theory against observations one had to ask: 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.
Such a process would require that the temperature be hot enough to produce deuterium, but not hot enough to produce helium-4, and that this process should immediately cool to non-nuclear temperatures after no more than a few minutes.
Now, if the universe was perfectly uniform at the time of recombination -- same density everywhere, same temperature everywhere -- then we should see a perfectly uniform microwave background. Nor does the length of a meterstick grow due to the expansion of the universe.
This has proved to be of limited usefulness in that the inconsistencies were resolved by better observations, and in most cases trying to change BBN resulted in abundances that were more inconsistent with observations rather than less.
Thanks to the pioneering efforts of George Gamow and his collaborators, there now exists a satisfactory theory as to the production of light elements in the early Universe. More recently, the question has changed: Dark energy is also an area of intense interest for scientists, but it is not clear whether direct detection of dark energy will be possible.
The denser the initial universe was, the more deuterium would be converted to helium-4 before time ran out, and the less deuterium would remain. When the universe was very young, it was likely infused with dark energy, but with less space and everything closer together, gravity predominated, and it was slowly braking the expansion.
Further details can be found here. It would also be necessary for the deuterium to be swept away before it reoccurs. In order to test these predictions, it is necessary to reconstruct the primordial abundances as faithfully as possible, for instance by observing astronomical objects in which very little stellar nucleosynthesis has taken place such as certain dwarf galaxies or by observing objects that are very far away, and thus can be seen in a very early stage of their evolution such as distant quasars.
Synthesis of these elements occurred either by nuclear fusion including both rapid and slow multiple neutron capture or to a lesser degree by nuclear fission followed by beta decay.
But these nuclei were totally ionized:.
In physical cosmology, Big Bang nucleosynthesis (or primordial nucleosynthesis) refers to the production of nuclei other than H-1, the normal. Big Bang lattice model, states that the universe at the moment of the Big Bang consists of an infinite lattice of fermions, which is smeared over the fundamental domain so it has rotational, translational and gauge symmetry.
The symmetry is the largest symmetry. Big Bang Nucleosynthesis The Universe's light-element abundance is another important criterion by which the Big Bang hypothesis is verified.
It is now known that the elements observed in the Universe were created in either of two ways. Big Bang Nucleosynthesis One of the primary successes of the Big Bang theory is its explanation for the chemical composition of the universe.
Recall that the universe is mostly hydrogen and helium, with very small amounts of heavier elements. Theory of Big Bang Nucleosynthesis The relative abundances of the lightest elements (hydrogen, deuterium, helium-3 and helium-4, and some lithium and beryllium) provide a strong test of the hypothesis that the.
Big-Bang nucleosynthesis 3 Figure The abundances of 4He, D, 3He and 7Li as predicted by the standard model of big-bang nucleosynthesis. Boxes indicate the observed light element abundances (smaller boxes: 2˙ statistical errors; larger boxes: 2˙ statistical and systematic errors).Bang nucleosynthesis model