An Etymological Dictionary of Astronomy and Astrophysics

The → Friedmann-Lemaitre model of → expanding Universe that only contains matter and in which space is → Euclidean (Ω_M > 0, Ω_R = 0, Ω_Λ = 0, k = 0). The Universe will expand at a decreasing rate for ever.

See also: → Einstein; de Sitter, after the Dutch mathematician and physicist Willem de Sitter (1872-1934) who worked out the model in 1917; → Universe.