Search results
Results from the WOW.Com Content Network
The evolution of the universe and its horizons in proper distances. The x-axis is distance, in billions of light years; the left-hand y-axis is time, in billions of years since the Big Bang; the right-hand y-axis is the scale factor. This is the same model as in the earlier figure, with dark energy and an event horizon.
Scale factor (cosmology) The expansion of the universe is parametrized by a dimensionless scale factor . Also known as the cosmic scale factor or sometimes the Robertson–Walker scale factor, [1] this is a key parameter of the Friedmann equations. In the early stages of the Big Bang, most of the energy was in the form of radiation, and that ...
In computer science, a scale factor is a number used as a multiplier to represent a number on a different scale, functioning similarly to an exponent in mathematics. A scale factor is used when a real-world set of numbers needs to be represented on a different scale in order to fit a specific number format. Although using a scale factor extends ...
e. The Lambda-CDM, Lambda cold dark matter, or ΛCDM model is a mathematical model of the Big Bang theory with three major components: a cosmological constant, denoted by lambda (Λ), associated with dark energy. the postulated cold dark matter, denoted by CDM. ordinary matter. It is referred to as the standard model of Big Bang cosmology [1 ...
The scale factor is a function of time and is conventionally set to be = at the present time. Because the universe is expanding, a {\displaystyle a} is smaller in the past and larger in the future. Extrapolating back in time with certain cosmological models will yield a moment when the scale factor was zero; our current understanding of ...
The definition of "accelerating expansion" is that the second time derivative of the cosmic scale factor, , is positive, which is equivalent to the deceleration parameter, , being negative. However, note this does not imply that the Hubble parameter is increasing with time.
e. The deceleration parameter in cosmology is a dimensionless measure of the cosmic acceleration of the expansion of space in a Friedmann–Lemaître–Robertson–Walker universe. It is defined by: where is the scale factor of the universe and the dots indicate derivatives by proper time. The expansion of the universe is said to be ...
In affine geometry, uniform scaling (or isotropic scaling[1]) is a linear transformation that enlarges (increases) or shrinks (diminishes) objects by a scale factor that is the same in all directions (isotropically). The result of uniform scaling is similar (in the geometric sense) to the original. A scale factor of 1 is normally allowed, so ...