What does the cosmological constant represent?
In cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: Λ), alternatively called Einstein’s cosmological constant, is the constant coefficient of a term Albert Einstein temporarily added to his field equations of general relativity.
What is a background metric?
Background Screening Metrics to Measure Use where you are now as a starting point. For example, if you have 1,000 background checks at one location and 100 come back with hits, and 150 background checks at one location but just 15 come back with hits, 10% of checks at both locations have hits.
What does scale factor mean in Robertson Walker metric?
If the value of the scale factor becomes 0 during the contraction of universe, it implies the distance between the objects becomes 0, i.e. the proper distance becomes 0. The comoving distance which is the distance between the objects at a present universe, is a constant quantity.
What did Friedmann do?
Friedmann universe, model universe developed in 1922 by the Russian meteorologist and mathematician Aleksandr Friedmann (1888–1925). He believed that Albert Einstein’s general theory of relativity required a theory of the universe in motion, as opposed to the static universe that scientists until then had proposed.
What does the Friedmann equation tell us?
The Friedmann equation which models the expanding universe has a parameter k called the curvature parameter which is indicative of the rate of expansion and whether or not that expansion rate is increasing or decreasing. It indicates the future fate of the universe.
Was Einstein a cosmologist?
Einstein himself lost little time in abandoning his static cosmology at that point. In the early 1930s, he published two distinct models of the expanding universe, one of positive spatial curvature and one of Euclidean geometry.
What is the meaning of Big Rip?
Definition of Big Rip astronomy. : a hypothetical cosmological event in which all matter in the universe loses cohesion and which is posited to be a possible fate of the universe if the outward acceleration of matter continues If the amount of dark energy increases with time, the future will be spectacular.