Big Bang nucleosynthesis (BBN)
haste-handâyeš-e Meh Bâng, ~ Big Bang
Fr.: nucléosynthèse de Big Bang
The production of → light elements, roughly three minutes after the → Big Bang when the temperature of the → Universe dropped from 1032 K to approximately 109 K. In a short time interval → protons and → neutrons collided to produce → deuterium. Most of the deuterium then fused with other protons and neutrons to produce → helium and a small amount of → tritium. The element → lithium 7 could also arise form the coalescence of one tritium and two deuterium nuclei. According to the Big Bang nucleosynthesis theory, roughly 25% of the mass of the Universe consists of helium. It also predicts about 0.01% deuterium, and even smaller quantities of lithium. These predictions depend critically on the → baryon-photon ratio. Same as → primordial nucleosynthesis.
→ Big Bang; → nucleosynthesis.
hasté andâyeš-e oskafti
Fr.: nucléosynthèse explosive
The explosive processes that are believed to occur in supernovae. Explosive carbon burning occurs at a temperature of about 2 × 109 degrees and produces the nuclei from neon to silicon. Explosive oxygen burning occurs near 4 × 109 degrees and produces nuclei between silicon and calcium in atomic weight.At higher temperatures, still heavier nuclei are produced.
→ explosive; → nucleosynthesis.
The process by which → nuclear reactions at very high temperatures and pressures produce the various → chemical elements of the → periodic table, either in the → Big Bang or in stellar interiors. See also → primordial nucleosynthesis, → stellar nucleosynthesis, → explosive nucleosynthesis.
From nucleo-, combining form of → nucleus + → synthesis.
Fr.: nucléosynthèse primordiale
The formation of → chemical elements in the → early Universe, between about 0.01 seconds and 3 minutes after the → Big Bang, when the nuclei of primordial matter collided and fused with one another. Most of the → helium in the → Universe was created by this process. Same as → Big Bang nucleosynthesis
→ primordial; → nucleosynthesis.
Fr.: nucléosynthèse stellaire
The → nuclear reaction process taking place inside stars, whereby → chemical elements are produced from pre-existing nuclei heavier than → hydrogen and → helium.
→ stellar; → nucleosynthesis.