How The Life Begin

These and other astronomical measurements constrain the spatial curvature to be very close to zero, although they do not constrain its sign. This means that although the local geometries of spacetime are generated by the theory of relativity based on  spacetime intervals , we can approximate 3-space by the familiar  Euclidean geometry . The  Friedmann–Lemaître–Robertson–Walker (FLRW) model  using  Friedmann equations  is commonly used to model the universe. The FLRW model provides a curvature of the universe based on the mathematics of  fluid dynamics , that is, modeling the matter within the universe as a perfect fluid. Although stars and structures of mass can be introduced into an "almost FLRW" model, a strictly FLRW model is used to approximate the local geometry of the observable universe. Another way of saying this is that if all forms of  dark energy  are ignored, then the curvature of the universe can...

General relativity  explains that mass and energy bend the curvature of spacetime and is used to determine what curvature the universe has by using a value called the  density parameter , represented with Omega (Ω). The density parameter is the average density of the universe divided by the critical energy density, that is, the mass energy needed for a universe to be flat. Put another way, If Ω = 1, the universe is flatIf Ω > 1, there is positive curvatureif Ω < 1 there is negative curvature One can experimentally calculate this Ωto determine the curvature two ways. One is to count up all the mass-energy in the universe and take its average density then divide that average by the critical energy density. Data from  Wilkinson Microwave Anisotropy Probe  (WMAP) as well as the  Planck spacecraft  give values for the three constituents of all the mass-energy in the universe – normal mass ( baryonic matter  and  dark ma...