WebOn the horizontal axis, we have the parameter eta. The scale is logarithmic; 10-9 corresponds to one proton or neutron for every billion photons, 10-8 to one for every hundred million, and so on (cf. the entry on exponential notation).The vertical axis indicates the different abundances. For for helium-4, it shows the mass ratio Y (the mass of …
Cosmic Evolution - Epoch 3 - Stellar Evolution - Harvard University
WebIn stars, ordinary helium is made by means of a two-step process, its validity directly confirmed in nuclear experiments conducted in laboratories around the world during the past few decades. First, an isotope of … WebSelect one: A. decoupling Event, about a million years after the Big Bang. B. end of the Inflationary Epoch, about 10-32 seconds into creation. C. beginning of particle production, about .0001 seconds into the universe. D. end of the Planck Era, about 10-43 seconds after the Big Bang. E. end of electron production, about a minute after creation. optecom s.a.s
Big Bang Nucleosynthesis: Cooking up the first light elements
WebAll heavier elements have been created by fusion inside of stars and during supernova explosions. Era of Nuclei During the next 500,000 years, the universe was too hot to form neutral atoms, and all of the particles … The recombination epoch begins at around 18,000 years, as electrons are combining with helium nuclei to form He+ . At around 47,000 years, [2] as the universe cools, its behavior begins to be dominated by matter rather than radiation. At around 100,000 years, after the neutral helium atoms form, helium hydride is the … See more The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 See more The Standard Model of cosmology is based on a model of spacetime called the Friedmann–Lemaître–Robertson–Walker (FLRW) metric. A metric provides a measure of distance between objects, and the FLRW metric is the exact solution of Einstein field equations See more After cosmic inflation ends, the universe is filled with a hot quark–gluon plasma, the remains of reheating. From this point onwards the … See more The universe has appeared much the same as it does now, for many billions of years. It will continue to look similar for many more billions of years into the future. Based upon the … See more Chronology in five stages For the purposes of this summary, it is convenient to divide the chronology of the universe since it See more During the earliest moments of cosmic time, the energies and conditions were so extreme that current knowledge can only suggest possibilities, which may turn out to be incorrect. To … See more 370 thousand to about 1 billion years after the Big Bang Dark Ages After recombination and decoupling, the universe was transparent and had cooled enough to allow light to travel long distances, but there … See more WebIn stars, ordinary helium is made by means of a two-step process, its validity directly confirmed in nuclear experiments conducted in laboratories around the world during the … optecore