Cosmological Expansion |

**In General**
s.a. expansion rate, issues and effects
[including global-local discrepancy] and acceleration; friedmann
equation; relativistic cosmology.

* __Hubble's law__: Introduced as the
relationship *v* = *H*_{0}*R*
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;
*H*_{0} is not really a constant;
Alternatively, *H*_{0} can be replaced
by its dimensionless counterpart *h* or "little *h*",
defined by *H*_{0} = 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.

@ __Original papers__:
Lemaître ASSB(27),
translation MNRAS(31);
Hubble PNAS(29);
Hubble & Humason ApJ(31).

@ __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 MNRAS(17)-a1705 [information-theoretic viewpoint];
> s.a. history of relativistic cosmology.

**Expansion History**
> s.a. Cosmography; 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];
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.

@ __Coasting models__: Sethi et al PLB(05)ap [viability];
John MNRASL-a1902 [history].

@ __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];
Wang & Meng PDU-a1709 [from galaxy cluster surveys];
Al Mamon & Bamba EPJC-a1805 [jerk parameter];
Gómez-Valent a1810.

@ __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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