When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Flatness problem - Wikipedia

    en.wikipedia.org/wiki/Flatness_problem

    The local geometry of the universe is determined by whether the relative density Ω is less than, equal to or greater than 1. From top to bottom: a spherical universe with greater than critical density (Ω>1, k>0); a hyperbolic, underdense universe (Ω<1, k<0); and a flat universe with exactly the critical density (Ω=1, k=0). The spacetime of ...

  3. Shape of the universe - Wikipedia

    en.wikipedia.org/wiki/Shape_of_the_universe

    For a flat (zero curvature) or a hyperbolic (negative curvature) spatial geometry, the topology can be either compact or infinite. [8] Many textbooks erroneously state that a flat or hyperbolic universe implies an infinite universe; however, the correct statement is that a flat universe that is also simply connected implies an infinite universe ...

  4. Flatness (cosmology) - Wikipedia

    en.wikipedia.org/wiki/Flatness_(cosmology)

    Such a space is called a "flat space" or Euclidean space [citation needed]. Whether the universe is “flat″ could determine its ultimate fate; whether it will expand forever, or ultimately collapse back into itself. The geometry of spacetime has been measured by the Wilkinson Microwave Anisotropy Probe (WMAP) to be nearly flat

  5. Friedmann equations - Wikipedia

    en.wikipedia.org/wiki/Friedmann_equations

    The spatial geometry of the universe has been measured by the WMAP spacecraft to be nearly flat. This means that the universe can be well approximated by a model where the spatial curvature parameter k is zero; however, this does not necessarily imply that the universe is infinite: it might merely be that the universe is much larger than the ...

  6. Olbers's paradox - Wikipedia

    en.wikipedia.org/wiki/Olbers's_Paradox

    The paradox is that a static, infinitely old universe with an infinite number of stars distributed in an infinitely large space would be bright rather than dark. [1] A view of a square section of four concentric shells. To show this, we divide the universe into a series of concentric shells, 1 light year thick.

  7. Cosmological perturbation theory - Wikipedia

    en.wikipedia.org/wiki/Cosmological_perturbation...

    Both cases apply only to situations where the universe is predominantly homogeneous, such as during cosmic inflation and large parts of the Big Bang. The universe is believed to still be homogeneous enough that the theory is a good approximation on the largest scales, but on smaller scales more involved techniques, such as N-body simulations ...

  8. Lambda-CDM model - Wikipedia

    en.wikipedia.org/wiki/Lambda-CDM_model

    The fraction of the total energy density of our (flat or almost flat) universe that is dark energy, , is estimated to be 0.669 ± 0.038 based on the 2018 Dark Energy Survey results using Type Ia supernovae [8] or 0.6847 ± 0.0073 based on the 2018 release of Planck satellite data, or more than 68.3 % (2018 estimate) of the mass–energy density ...

  9. Static universe - Wikipedia

    en.wikipedia.org/wiki/Static_universe

    In cosmology, a static universe (also referred to as stationary, infinite, static infinite or static eternal) is a cosmological model in which the universe is both spatially and temporally infinite, and space is neither expanding nor contracting. Such a universe does not have so-called spatial curvature; that is to say that it is 'flat' or ...