Search results
Results from the WOW.Com Content Network
Hubble's law is considered the first observational basis for the expansion of the universe, and is one of the pieces of evidence most often cited in support of the Big Bang model. [8] [17] The motion of astronomical objects due solely to this expansion is known as the Hubble flow. [18]
The comoving distance from an observer to a distant object (e.g. galaxy) can be computed by the following formula (derived using the Friedmann–Lemaître–Robertson–Walker metric): = ′ (′) where a(t′) is the scale factor, t e is the time of emission of the photons detected by the observer, t is the present time, and c is the speed of ...
Hubble radius, Hubble sphere (not to be confused with a Hubble bubble), Hubble volume, or Hubble horizon is a conceptual horizon defining the boundary between particles that are moving slower and faster than the speed of light relative to an observer at one given time. Note that this does not mean the particle is unobservable; the light from ...
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 ...
Distance measures are used in physical cosmology to give a natural notion of the distance between two objects or events in the universe.They are often used to tie some observable quantity (such as the luminosity of a distant quasar, the redshift of a distant galaxy, or the angular size of the acoustic peaks in the cosmic microwave background (CMB) power spectrum) to another quantity that is ...
Distance moduli are most commonly used when expressing the distance to other galaxies in the relatively nearby universe.For example, the Large Magellanic Cloud (LMC) is at a distance modulus of 18.5, [2] the Andromeda Galaxy's distance modulus is 24.4, [3] and the galaxy NGC 4548 in the Virgo Cluster has a DM of 31.0. [4]
The redshift given by the formula + = () Any function with a zero subscript denote the function evaluated at the present time t 0 {\displaystyle t_{0}} (or equivalently z = 0 {\displaystyle z=0} ). The last term can be taken to be 1 {\displaystyle 1} including the curvature state equation. [ 7 ]
It relates the proper distance (which can change over time, unlike the comoving distance which is constant and set to today's distance) between a pair of objects, e.g. two galaxy clusters, moving with the Hubble flow in an expanding or contracting FLRW universe at any arbitrary time to their distance at some reference time .