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  2. Hubble's law - Wikipedia

    en.wikipedia.org/wiki/Hubble's_law

    Hubble's law can be easily depicted in a "Hubble diagram" in which the velocity (assumed approximately proportional to the redshift) of an object is plotted with respect to its distance from the observer. [30] A straight line of positive slope on this diagram is the visual depiction of Hubble's law.

  3. Cosmic distance ladder - Wikipedia

    en.wikipedia.org/wiki/Cosmic_distance_ladder

    The observational result of Hubble's law, the proportional relationship between distance and the speed with which a galaxy is moving away from us, usually referred to as redshift, is a product of the cosmic distance ladder. Edwin Hubble observed that fainter galaxies are more redshifted. Finding the value of the Hubble constant was the result ...

  4. Age of the universe - Wikipedia

    en.wikipedia.org/wiki/Age_of_the_universe

    The first observation that one can make from this formula is that it is the Hubble parameter that controls that age of the universe, with a correction arising from the matter and energy content. So a rough estimate of the age of the universe comes from the Hubble time, the inverse of the Hubble parameter.

  5. Tired light - Wikipedia

    en.wikipedia.org/wiki/Tired_light

    Tired light was an idea that came about due to the observation made by Edwin Hubble that distant galaxies have redshifts proportional to their distance.Redshift is a shift in the spectrum of the emitted electromagnetic radiation from an object toward lower energies and frequencies, associated with the phenomenon of the Doppler effect.

  6. Friedmann equations - Wikipedia

    en.wikipedia.org/wiki/Friedmann_equations

    The Hubble parameter can change over time if other parts of the equation are time dependent (in particular the mass density, the vacuum energy, or the spatial curvature). Evaluating the Hubble parameter at the present time yields Hubble's constant which is the proportionality constant of Hubble's law .

  7. Hubble–Reynolds law - Wikipedia

    en.wikipedia.org/wiki/Hubble–Reynolds_law

    The law is named for the astronomers Edwin Hubble and John Henry Reynolds. It was first formulated by Reynolds in 1913 [ 2 ] from his observations of galaxies (then still known as nebulae). It was later re-derived by Hubble in 1930 [ 3 ] specifically in observations of elliptical galaxies.

  8. Recessional velocity - Wikipedia

    en.wikipedia.org/wiki/Recessional_velocity

    where is the Hubble constant, is the proper distance, is the object's recessional velocity, and is the object's peculiar velocity. The recessional velocity of a galaxy can be calculated from the redshift observed in its emitted spectrum. One application of Hubble's law is to estimate distances to galaxies based on measurements of their ...

  9. Expansion of the universe - Wikipedia

    en.wikipedia.org/wiki/Expansion_of_the_universe

    Hubble's law predicts that objects farther than the Hubble horizon are receding faster than light. This outcome is not in violation of special relativity . Since special relativity treats flat spacetimes, it is only valid over small distances within the context of the curved spacetime of the universe.