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The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. [ 1] It was first proposed as a physical theory in 1931 by Roman Catholic priest and physicist Georges Lemaître when he suggested the universe emerged from a "primeval atom". Various cosmological models of the Big ...
The Friedmann equations, also known as the Friedmann–Lemaître ( FL) equations, are a set of equations in physical cosmology that govern the expansion of space in homogeneous and isotropic models of the universe within the context of general relativity. They were first derived by Alexander Friedmann in 1922 from Einstein's field equations of ...
Thus, an accelerating universe took a longer time to expand from 2/3 to 1 times its present size, compared to a non-accelerating universe with constant ˙ and the same present-day value of the Hubble constant. This results in a larger light-travel time, larger distance and fainter supernovae, which corresponds to the actual observations.
The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time. [ 1] It is an intrinsic expansion, so it does not mean that the universe expands "into" anything or that space exists "outside" it. To any observer in the universe, it appears that all but the nearest galaxies ...
The universe is all of space and time [ a] and their contents. [ 10] It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from sub-atomic particles to entire galactic filaments. Space and time, according to the prevailing ...
This time happens to correspond roughly to the time of the formation of the Solar System and the evolutionary history of life. Stelliferous Era: 150 Ma ~ 100 Ta [16] 20 ~ −0.99: 60 K ~ 0.03 K: The time between the first formation of Population III stars until the cessation of star formation, leaving all stars in the form of degenerate ...
The minimum of it is only 1, not 0 as needed, and the negative outputs for inputs smaller than 10 are useless. Therefore, the time from 0.1 to 10 years is collapsed to a single point 0, but that does not matter in this case because nothing special happens in the history of the universe during that time.
Each individual reaction produces only a tiny amount of energy, but because enormous numbers of these reactions occur constantly, they produce all the energy necessary to sustain the star's radiation output. In comparison, the combustion of two hydrogen gas molecules with one oxygen gas molecule releases only 5.7 eV.