Cosmological Expansion  

In General blue bullet s.a. expansion rate, issues and effects [including global-local dicrepancy] and acceleration; friedmann equation; relativistic cosmology.
* Hubble's law: Introduced as the relationship v = H0R between a distant galaxy's recession speed and its distance, it actually relates the distance to the galaxy's redshift z observationally, or its comoving distance to the time rate of change of its comoving distance theoretically; H0 is not really a constant; Alternatively, H0 can be replaced by its dimensionless counterpart h or "little h", defined by H0 = 100 h km/s/Mpc.
* History: Credit for the discovery is given to Edwin Hubble (1929), but the work of Lemaître (1927) has been neglected; Mechanisms such as Zwicky's 1929 "tired light" were proposed as alternative explanations for the redshift; Hubble was initially reluctant to accept the expansion as real! 1970s, Alan Sandage defined cosmology as the search for two numbers, the Hubble parameter \(H_0\) and deceleration parameter \(q_0\).
* Measurements: Calculations of the value of Hubble's constant use redshift and distance measurements; Some high-precision distance-determination methods use Cepheids, the tip of the red giant branch, maser galaxies, surface-brightness fluctuations, the Tully-Fisher relation and Type-Ia supernovae; 2012, Recently proposed methods use galaxy clusters and gravitational waves.
@ General references: Criado & Alamo AJP(07)apr [motion of photons and galaxies]; Linder RPP(08)-a0801 [rev]; Greenhill et al a0902-rp [measurement]; Padmanabhan GRG(10)-a1001 [and gravitational action and thermodynamics]; Wallace & Prather AJP(12)may [use for teaching introductory physics]; Neben & Turner ApJ(13)-a1209 [using time dependence of redshifts]; Croton PASA(13)-a1308 [dealing with little h in data analysis]; Sloan & Silk PRD(16)-a1505 [reason for large expansion].
@ Conceptual: Silverman AJP(86)dec [apparent paradoxes]; Page gq/93 [apparent superluminal expansion]; Peacock a0809; Kaya AJP(11)-a1107; Padmanabhan RAA(12)-a1207 [expansion of the universe as emergence of space]; Toporensky & Popov PU(14)-a1311 [observer perspective]; Hogan a1312 [quantum indeterminacy in local measurement of cosmic expansion]; Pandey a1705 [information-theoretic viewpoint]; > s.a. history of relativistic cosmology.

Expansion History > s.a. cosmology [including future].
* 2016: The most accurate measurements have been obtained with Type Ia supernovae and Baryon Acoustic Oscillations, providing evidence for the existence of a transition epoch from a decelerated to an accelerated expansion rate.
@ General references: Linder PRL(03)ap/02; Simon et al PRD(05); Shafieloo et al MNRAS(06)ap/05 [from supernova data]; Wang & Tegmark PRD(05) [measurement method]; Sethi et al PLB(05)ap [viability of linearly coasting model]; Linder PRD(05)ap [and inhomogeneity growth history]; Bonvin et al PRL(06) [H(z) from luminosity distance dipole]; Nojiri & Odintsov JPCS(07)ht/06 [and reconstruction of modified gravity theory]; Schaefer ApJ(07)ap/06 [Hubble diagram to z > 6]; Figueroa et al JCAP(08)-a0807 [and cosmological parameters]; Mörtsell & Clarkson JCAP(09)-a0811 [constraints]; Linder & Smith JCAP(11)-a1009 [excluding early acceleration periods]; Santos et al APP(11)-a1009 [switch from deceleration to acceleration]; Barboza & Carvalho PLB(12) [kinematic probe]; Shchigolev UJPA(13)-a1404 [toy model of complete history]; > s.a. acceleration.
@ Reconstruction: Ishida & de Souza A&A(11)-a1012; Shafieloo JCAP(12)-a1204 [high-precision]; Samsing et al PRD(12)-a1208 [model-independent, from cmb observations]; Song PRD(13)-a1210 [using redshift distortions]; Shafieloo et al PRD(13)-a1211 [model-independent, from supernova data]; news sn(12)nov [BOSS finds expansion was slowing down 11 Gyr ago]; Hamaus et al JCAP(14)-a1409 [using the clustering statistics of cosmic voids]; Li et al PRD(16)-a1504 [H(z) as a function of redshift]; Vitenti & Penna-Lima JCAP(15)-a1505; Hamaus et al JCAP(15)-a1507 [using redshift-space distortions]; Moresco et al JCAP(16)-a1601 [evidence for transition from decelerated to accelerated expansion]; Crevecoeur a1603 [in light of Planck data]; Feng & Li ApJ(16)-a1604 [from SN and GRB measurements].
@ And gravitational waves: Izquierdo AIP(06)gq [relic gravitational waves]; Linder JCAP(08)-a0711, Nishizawa et al PRD(11) [sirens]; Messenger & Read PRL(12) [from binary neutron star coalescence].
@ In f(R) gravity: Amarzguioui et al A&A(06)ap/05 [Palatini]; Fairbairn & Rydeck JCAP(07)ap.

Other References > s.a. doppler effect global geometry[including distance-redshift relation].
@ Distance measurements: Feast ASP-ap/04; Allen et al a1307 [rev]; Fakhouri et al ApJ(15)-a1511 [using "twin" Type Ia supernovae].
@ Related topics: Goldhaber et al ap/96-in [cosmological time dilation]; Scott & Frolop ap/06 [(not CJP) coincidences]; Cooray & Caldwell PRD(06) [complications from bulk motions]; Coley et al IJMPD(06)gq [observer dependence]; Cattoën & Visser CQG(07)-a0710 [expansions in powers of z]; Uzan et al PRL(08) [time drift of cosmological redshift]; Guzzo et al nat(08)jan + news pw(08)jan [redshift distortion]; Qi & Lu a1001 [direct measurement proposal]; Christiansen & Siver AJP(12)may-a1204 [brightness and angular size in an expanding universe]; López-Corredoira PoS-a1501 [tests of expansion].
@ Arguments against expansion: Petry ASS(97) [redshift]; Sumner ap/04 [contraction!]; Whiting Obs-ap/04; Moret-Bailly ap/04; Chodorowski ONCP(07)ap/06; Bunn & Hogg AJP(09)-a0808 [Doppler shift as opposed to stretching]; Chodorowski a0812; Crawford a0901 [no evidence of time dilation in GRBs], a0901 [supernovae]; López-Corredoira IJMPD(10) [angular-size test]; Rebhan PRD(12)-a1211 [expansion of space is just an interpretation]; Janzen a1303-FQXi; Kragh a1507 [Jacob Halm's 1935 paper].
@ The universe does expand: Lineweaver & Davis SA(05)mar; Abramowicz et al ap/06, a0812 [expansion vs motion of galaxies is verifiable]; Faraoni GRG(10)-a0908.
@ Other unconventional views: Leffert ap/05 [spatial condensation]; Grøn & Elgarøy AJP(07)feb-ap/06 [response]; He ap/06 [flat spacetime]; Francis et al PASA(07)-a0707; Lewis et al MNRAS(07)-a0707 [counterargument]; Tomozawa a0710 [center of expansion, from cmb dipole]; Cook & Burns AJP(09)-a0803 [FLRW model with different interpretation]; Baryshev a0810-proc ["paradoxes"]; Christensen a0810; Farley PRS(10)-a1005 [no gravity between galaxies and no dark energy]; Chernin a1107; Jain MPLA(12) [no expansion, increasing particle masses]; Lewis AusP-a1605; > s.a. FLRW models.

I awoke on Friday and because the universe is expanding it took me longer than usual to find my robe...
– Woody Allen, in "Strung Out" The New Yorker, 18 Jul 2003.

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