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According to the theory of cosmic inflation, the very early universe underwent a period of very rapid, quasi-exponential expansion.While the time-scale for this period of expansion was far shorter than that of the existing expansion, this was a period of accelerated expansion with some similarities to the current epoch.
A higher expansion rate would imply a smaller characteristic size of CMB fluctuations, and vice versa. The Planck collaboration measured the expansion rate this way and determined H 0 = 67.4 ± 0.5 (km/s)/Mpc. [26] There is a disagreement between this measurement and the supernova-based measurements, known as the Hubble tension.
The universe's expansion rate, a figure called the Hubble constant, is measured in kilometers per second per megaparsec, a distance equal to 3.26 million light-years.
One of the ways the universe can be illuminated is if two carbon–oxygen white dwarfs with a combined mass of more than the Chandrasekhar limit of about 1.4 solar masses happen to merge. The resulting object will then undergo runaway thermonuclear fusion, producing a Type Ia supernova and dispelling the darkness of the Degenerate Era for a few ...
The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. [1] The concept of an expanding universe was scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations.
Here is the Hubble parameter, a measure of the rate at which the universe is expanding. ρ {\displaystyle \rho } is the total density of mass and energy in the universe, a {\displaystyle a} is the scale factor (essentially the 'size' of the universe), and k {\displaystyle k} is the curvature parameter — that is, a measure of how curved ...
In physical cosmology, the Big Rip is a hypothetical cosmological model concerning the ultimate fate of the universe, in which the matter of the universe, from stars and galaxies to atoms and subatomic particles, and even spacetime itself, is progressively torn apart by the expansion of the universe at a certain time in the future, until distances between particles will infinitely increase.
The rapid expansion immediately after the Big Bounce explains why the present Universe at largest scales appears spatially flat, homogeneous and isotropic. As the density of the Universe decreases, the effects of torsion weaken and the Universe smoothly enters the radiation-dominated era.