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Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the elements heavier than hydrogen.
Big bang nucleosynthesis refers to the process of element production during the early phases of the universe, shortly after the Big Bang. It is believed to be responsible for the formation of hydrogen, its isotope deuterium, helium in its varieties 3He and 4He, and the isotope of lithium 7Li.
Big Bang nucleosynthesis
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Big Bang ~
Gamow, Alpher and Herman proposed the hot Big Bang as a means to produce all of the elements. However, the lack of stable nuclei with atomic weights of 5 or 8 limited the Big Bang to producing hydrogen and helium.
~ and Fusion Reactions
~ simply refers to the production of nuclei heavier than hydrogen. This occurs in main sequence stars through two main processes, the proton-proton chain and the CNO cycle (carbon, nitrogen, oxygen).
(a) The transformation of one element or isotope into another. ~ occurred just after the big bang, but today most ~ takes place in stars - for example, the Sun presently converts hydrogen into helium.
The production of elements heavier than helium by the fusion of atomic nuclei in stars and during supernova explosions.
~: Element formation by reactions inside stars.
Nucleus: (see comet) Kilometer-sized "dirty snowball" composed of dust (refractory material) and primarily water-ice which gives rise to all of the features observers associate with comets.
The processes whereby elements heavier than hydrogen are built up from hydrogen.
~ - The building up of more massive elements from less massive elements through nuclear reactions in stars
Nucleoitide - The class of organic molecules of which nucleic acids are composed ...
~ Era, time=3 minutes, Temperature = 109 K.
Figure 2. Click to see a larger version. This graph shows how the composition of the Universe changed with time since the Big Bang - not much time, though.
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stellar ~ The formation of heavy elements by the fusion of lighter nucleii in the hearts of stars. Except for hydrogen and helium, all other elements in our universe result from stellar ~.
~ requires a high-speed collision, which can only be achieved with very high temperature. The minimum temperature required for the fusion of hydrogen is 5 million degrees. Elements with more protons in their nuclei require still higher temperatures.
~ ((astronomy) the cosmic synthesis of atoms more complex than the hydrogen atom)
libration ((astronomy) a real or apparent slow oscillation of a moon or satellite) ...
~ The creation of new elements in stars by combining lighter nuclei to make heavier nuclei.
More about ~...
~ The building up of heavy elements from lighter ones by nuclear fusion.
nucleus Dense, central region of an atom, containing both protons and neutrons, and orbited by one or more electrons.
~: The First Atoms
When the universe had been in existence for 1 second, it had cooled to approximately 1010 K (2x1010 °F) (1000 times hotter than the core of the sun). Finally, light atomic nuclei could form.
~ is the production of new elements via nuclear reactions. ~ takes place in stars. It also took place soon after the Big Bang.
~: The process by which nuclear reactions produce the various elements of the periodic table.
Why is ~ in the Big Bang different from ~ in stars?
The answer lies in the particles present in the early Universe and the temperatures and densities present when nuclear reactions are occurring: ...
The fusion of light elements during the early hot phase of the big bang, to produce heavier elements. It resulted in nearly a quarter of the mass of the universe being turned from hydrogen into helium.
cosmic rays ...
Big Bang ~
Big Bang ~ refers to the production of nuclei other than those of 1H (i.e. the normal, light isotope of hydrogen, whose nucleus consists of a single proton) during the early phases of the universe.
Element building that occurred in the early universe when the nuclei of primordial matter collided and fused with one another. Most of the helium in the universe was created by this process.
BIG BANG ~ - Formation of elements in the Big Bang. Calculated abundances of these isotopes (D (deuterium = 2H), 3H, 3He, 4He, 6Li, 7Li, and 7Be) and of protons (1H) and neutrons (n) vs. time are shown in the diagram.
Primordial ~ also depends on the number of flavors of neutrino; the more there are, the more neutrons will be produced in the early universe and the more helium will remain. The value above implies only three kinds of leptons, fortunately allowed by the three known generations.
(a) The creation of elements that occurred just minutes after the Big Bang. According to standard theory, primordial ~ gave the Universe only five nuclei, all lightweight: hydrogen-1, hydrogen-2 (or deuterium), helium-3, helium-4, and lithium-7. [C95] ...
Thanks for the ~ explanations people. I clean forgot about solar (stellar) winds. D'oh!
re: other scientists turning over their telescopes.
The abundances of the lightest elements (hydrogen, helium, deuterium, lithium) are consistent with their creation in a Big Bang event and not via subsequent ~ in stars.
Nuclear Fusion and ~
Stars are giant nuclear reactors. In the center of stars, atoms are taken apart by tremendous atomic collisions that alter the atomic structure and release an enormous amount of energy. This makes stars hot and bright.
"The constraints on the density of baryonic [normal] matter from ~ and the cosmic microwave background radiation tells us that if MACHOs exist they have to be non-baryonic," says Green.
The first three minutes / big bang ~, deuterium
Microwave Background Radiation: recombination, anisotropy, Sunyaev-Zeldovich effect
dark matter: MACHO, WIMP, neutrino
de Sitter space, Friedmann-Robertson-Walker metric(*), Newtonian derivation of the Friedmann equation ...
The term "Primordial ~" refers to the production of chemical elements with more than one proton a few moments after the Big Bang. This production happened in a very short time, allowing only hydrogen, helium, and lithium to form, but no heavier elements.
Hoyle later helped considerably in the effort to understand stellar ~, the nuclear pathway for building certain heavier elements from lighter ones. After the discovery of the cosmic microwave background radiation in 1964, and especially when its spectrum (i.e.
Sir Fred Hoyle Fellow of the Royal Society was an England astronomer primarily remembered today for his contribution to the theory of stellar ~ and his often controversial stance on other Cosmology and scientific matters, in particular his rejection of the Big Bang theory....
This brings us to the important issue of ~, or the creation of the nuclei. The universe is mostly composed of hydrogen and helium. All the rest of the elements of the periodic table are built up in the interior of stars through nuclear reactions.
Hydrogen (deuterium) helium and some lithium were created by ~ just after the Big Bang. The next heaviest elements (like carbon, nirogen, and oxygen) are formed inside stars via fusion. Most stars fuse hydrogen, forming helium.
The primordial nucleons (hydrogen and helium) themselves were formed from the quark-gluon plasma in the first few minutes after the Big Bang, as it cooled to below ten million degrees, but ~ of the heavier elements (including all carbon, oxygen, etc) occurs primarily in the nuclear ...
See also: What is the meaning of Astro, Solar, Sun, Star, Planet?