Editing Redshift (section)

===Highest redshifts===
{{see also|List of the most distant astronomical objects#List of most distant objects by type{{!}}List of most distant objects by type}}
[[File:Comoving distance and lookback time (Planck 2018).png|thumb|upright=1.8|[[Comoving and proper distances|Comoving distance]] and [[lookback time]] for the Planck 2018 cosmology parameters, from redshift 0 to 15, with distance (blue solid line) on the left axis, and time (orange dashed line) on the right. Note that the time that has passed (in giga years) from a given redshift until now is not the same as the distance (in giga light years) light would have traveled from that redshift, due to the expansion of the universe over the intervening period.]]

The most reliable redshifts are from [[spectroscopic]] data,<ref>{{Cite web |title=Redshift |url=https://lco.global/spacebook/light/redshift/ |access-date=2025-03-06 |website=lco.global |publisher=[[Las Cumbres Observatory]] |language=en}}</ref> and the highest-confirmed spectroscopic redshift of a galaxy is that of [[JADES-GS-z14-0]] with a redshift of {{math|''z'' {{=}} 14.32}}, corresponding to 290 million years after the Big Bang.<ref>{{Cite journal |last1=Carniani |first1=Stefano |last2=Hainline |first2=Kevin |last3=D'Eugenio |first3=Francesco |last4=Eisenstein |first4=Daniel J. |last5=Jakobsen |first5=Peter |last6=Witstok |first6=Joris |last7=Johnson |first7=Benjamin D. |last8=Chevallard |first8=Jacopo |last9=Maiolino |first9=Roberto |last10=Helton |first10=Jakob M. |last11=Willott |first11=Chris |last12=Robertson |first12=Brant |last13=Alberts |first13=Stacey |last14=Arribas |first14=Santiago |last15=Baker |first15=William M. |date=2024-07-29 |title=Spectroscopic confirmation of two luminous galaxies at a redshift of 14 |journal=Nature |volume=633 |issue=8029 |language=en |pages=318–322 |doi=10.1038/s41586-024-07860-9 |issn=1476-4687|doi-access=free |pmid=39074505 |pmc=11390484 |arxiv=2405.18485 |bibcode=2024Natur.633..318C }}</ref> The previous record was held by [[GN-z11]],<ref>{{cite journal
 | title=A Remarkably Luminous Galaxy at z=11.1 Measured with Hubble Space Telescope Grism Spectroscopy
 | last1=Oesch | first1=P. A. | last2=Brammer | first2=G.
 | last3=van Dokkum | first3=P. G. | last4=Illingworth | first4=G. D.
 | last5=Bouwens | first5=R. J. | last6=Labbé | first6=I.
 | last7=Franx | first7=M. | last8=Momcheva | first8=I.
 | last9=Ashby | first9=M. L. N. | last10=Fazio | first10=G. G.
 | last11=Gonzalez | first11=V. | last12=Holden | first12=B.
 | last13=Magee | first13=D. | last14=Skelton | first14=R. E.
 | last15=Smit | first15=R. | last16=Spitler | first16=L. R.
 | last17=Trenti | first17=M. | last18=Willner | first18=S. P.
 | display-authors=1 | journal=The Astrophysical Journal
 | date=March 1, 2016 | volume=819 | issue=2 | page=129
 | arxiv=1603.00461 | doi=10.3847/0004-637X/819/2/129
 | bibcode=2016ApJ...819..129O | s2cid=119262750
| doi-access=free }}</ref> with a redshift of {{math|''z'' {{=}} 11.1}}, corresponding to 400 million years after the Big Bang.

Slightly less reliable are [[Lyman-break galaxy|Lyman-break]] redshifts, the highest of which is the lensed galaxy A1689-zD1 at a redshift {{math|''z'' {{=}} 7.5}}<ref>{{Cite journal|last1=Watson|first1=Darach|last2=Christensen|first2=Lise|last3=Knudsen|first3=Kirsten Kraiberg|last4=Richard|first4=Johan|last5=Gallazzi|first5=Anna|last6=Michałowski|first6=Michał Jerzy|title=A dusty, normal galaxy in the epoch of reionization|journal=Nature|volume=519|issue=7543|pages=327–330|doi=10.1038/nature14164|arxiv = 1503.00002 |bibcode = 2015Natur.519..327W|pmid=25731171|year=2015|s2cid=2514879}}</ref><ref>{{cite journal
 | title=Discovery of a Very Bright Strongly Lensed Galaxy Candidate at z ~ 7.6
 | first1=L. D. | last1=Bradley | first2=R. J. | last2=Bouwens
 | first3=H. C. | last3=Ford | first4=G. D. | last4=Illingworth
 | first5=M. J. | last5=Jee | first6=N. | last6=Benítez
 | first7=T. J. | last7=Broadhurst | first8=M. | last8=Franx
 | first9=B. L. | last9=Frye | first10=L. | last10=Infante
 | display-authors=1 | journal=[[The Astrophysical Journal]]
 | volume=678 | issue=2 | pages=647–654 | year=2008
 | bibcode=2008ApJ...678..647B | s2cid=15574239
 | doi=10.1086/533519 | arxiv=0802.2506
}}</ref> and the next highest being {{math|''z'' {{=}} 7.0}}.<ref>{{cite journal
 | display-authors=1 | first1=E. | last1=Egami
 | first2=J.-P. | last2=Kneib | first3=G. H. | last3=Rieke
 | first4=R. S. | last4=Ellis | first5=J. | last5=Richard
 | first6=J. | last6=Rigby | first7=C. | last7=Papovich
 | first8=D. | last8=Stark | first9=M. R. | last9=Santos
 | first10=J.-S. | last10=Huang | first11=H. | last11=Dole
 | first12=E. Le | last12=Floc'H | first13=P. G. | last13=Pérez-González
 | title=Spitzer and Hubble Space Telescope Constraints on the Physical Properties of the z~7 Galaxy Strongly Lensed by A2218
 | journal=[[The Astrophysical Journal]]
 | volume=618 | issue=1 | pages=L5–L8 | year=2005
 | bibcode=2005ApJ...618L...5E | doi=10.1086/427550
 | arxiv=astro-ph/0411117 | s2cid=15920310 }}</ref> The most distant-observed [[gamma-ray burst]] with a spectroscopic redshift measurement was [[GRB 090423]], which had a redshift of {{math|''z'' {{=}} 8.2}}.<ref>{{cite journal
 | title=GRB 090423 reveals an exploding star at the epoch of re-ionization
 | last1=Salvaterra | first1=R. | first2=M. Della | last2=Valle
 | last3=Campana | first3=S. |author-link3=Sergio Campana (astrophysicist)| last4=Chincarini | first4=G.
 | last5=Covino | first5=S. | last6=d'Avanzo | first6=P.
 | last7=Fernández-Soto | first7=A. | last8=Guidorzi | first8=C.
 | last9=Mannucci | first9=F. | last10=Margutti | first10=R.
 | last11=Thöne | first11=C. C. | last12=Antonelli | first12=L. A.
 | last13=Barthelmy | first13=S. D. | last14=De Pasquale | first14=M.
 | last15=d'Elia | first15=V. | last16=Fiore | first16=F.
 | last17=Fugazza | first17=D. | last18=Hunt | first18=L. K.
 | last19=Maiorano | first19=E. | last20=Marinoni | first20=S.
 | last21=Marshall | first21=F. E. | last22=Molinari | first22=E.
 | last23=Nousek | first23=J. | last24=Pian | first24=E.
 | last25=Racusin | first25=J. L. | last26=Stella | first26=L.
 | last27=Amati | first27=L. | last28=Andreuzzi | first28=G.
 | last29=Cusumano | first29=G. | last30=Fenimore | first30=E. E.
 | display-authors=4 | journal=[[Nature (journal)|Nature]]
 | volume=461 | issue=7268 | pages=1258–60
 | doi=10.1038/nature08445 | date=2009 | pmid=19865166
 | s2cid=205218263 | bibcode=2009Natur.461.1258S |arxiv=0906.1578
 }}</ref> The most distant-known quasar, [[ULAS J1342+0928]], is at {{math|''z'' {{=}} 7.54}}.<ref>{{cite web|url=https://news.mit.edu/2017/scientists-observe-supermassive-black-hole-infant-universe-1206|title=Scientists observe supermassive black hole in infant universe|website=MIT News |publisher=Massachusetts Institute of Technology |date=2017-12-06 |first=Jennifer |last=Chu}}</ref><ref name="Nature-2018-01">{{cite journal |last1=Bañados |first1=Eduardo |last2=Venemans |first2=Bram P. |last3=Mazzucchelli |first3=Chiara |last4=Farina |first4=Emanuele P. |last5=Walter |first5=Fabian |last6=Wang |first6=Feige |last7=Decarli |first7=Roberto |last8=Stern |first8=Daniel |last9=Fan |first9=Xiaohui |last10=Davies |first10=Frederick B. |last11=Hennawi |first11=Joseph F. |last12=Simcoe |first12=Robert A. |last13=Turner |first13=Monica L. |last14=Rix |first14=Hans-Walter |last15=Yang |first15=Jinyi |last16=Kelson |first16=Daniel D. |last17=Rudie |first17=Gwen C. |last18=Winters |first18=Jan Martin |title=An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5 |journal=Nature |date=January 2018 |volume=553 |issue=7689 |pages=473–476 |doi=10.1038/nature25180 |pmid=29211709 |arxiv=1712.01860 |bibcode=2018Natur.553..473B |s2cid=205263326 }}</ref> The highest-known redshift radio galaxy (TGSS1530) is at a redshift {{math|''z'' {{=}} 5.72}}<ref>{{cite journal|last1=Saxena|first1=A.|date=2018|title=Discovery of a radio galaxy at z = 5.72|journal=Monthly Notices of the Royal Astronomical Society|volume=480|issue=2|pages=2733–2742|arxiv=1806.01191|bibcode=2018MNRAS.480.2733S|doi=10.1093/mnras/sty1996|doi-access=free |s2cid=118830412}}</ref> and the highest-known redshift molecular material is the detection of emission from the CO molecule from the quasar SDSS J1148+5251 at {{math|''z'' {{=}} 6.42}}.<ref>{{cite journal | doi = 10.1038/nature01821 | title = Molecular gas in the host galaxy of a quasar at redshift z = 6.42 | date = 2003 | last1 = Walter | first1 = Fabian | last2 = Bertoldi | first2 = Frank | last3 = Carilli | first3 = Chris | last4 = Cox | first4 = Pierre | last5 = Lo | first5 = K. Y. | last6 = Neri | first6 = Roberto | last7 = Fan | first7 = Xiaohui | last8 = Omont | first8 = Alain | last9 = Strauss | first9 = Michael A. | last10 = Menten | first10 = Karl M. | journal = Nature | volume = 424 | issue = 6947 | pages = 406–8 | pmid = 12879063 |bibcode=2003Natur.424..406W|arxiv = astro-ph/0307410 |s2cid = 4419009| display-authors = 4 }}</ref>

''Extremely red objects'' (EROs) are [[Radio astronomy#Astronomical sources|astronomical sources]] of radiation that radiate energy in the red and near infrared part of the electromagnetic spectrum. These may be starburst galaxies that have a high redshift accompanied by reddening from intervening dust, or they could be highly redshifted elliptical galaxies with an older (and therefore redder) stellar population.<ref>
{{cite journal
 | display-authors=4
 | author=Smail, Ian
 | author2=Owen, F. N.
 | author3=Morrison, G. E.
 | author4=Keel, W. C.
 | author5=Ivison, R. J.
 | author6=Ledlow, M. J.
 | journal=The Astrophysical Journal | volume=581 | issue=2
 | pages=844–864 | doi=10.1086/344440 | bibcode=2002ApJ...581..844S
 | title=The Diversity of Extremely Red Objects
 | date=2002
|arxiv = astro-ph/0208434 | s2cid=51737034
 }}</ref> Objects that are even redder than EROs are termed ''hyper extremely red objects'' (HEROs).<ref>
{{cite journal
 | display-authors=4
 | author=Totani, Tomonori
 | author2=Yoshii, Yuzuru
 | author3=Iwamuro, Fumihide
 | author4=Maihara, Toshinori
 | author5=Motohara, Kentaro
 | title=Hyper Extremely Red Objects in the Subaru Deep Field: Evidence for Primordial Elliptical Galaxies in the Dusty Starburst Phase
 | journal=The Astrophysical Journal | volume=558 | issue=2
 | date=2001 | pages=L87–L91 | doi=10.1086/323619
 | bibcode=2001ApJ...558L..87T
|arxiv = astro-ph/0108145 | s2cid=119511017
 }}</ref>

The [[cosmic microwave background]] has a redshift of {{math|z {{=}} 1089}}, corresponding to an age of approximately 379,000 years after the Big Bang and a [[Comoving and proper distances|proper distance]] of more than 46 billion light-years.<ref name="ly93">
{{cite journal | last1 = Lineweaver | first1 = Charles | first2=Tamara M. | last2=Davis | date = 2005 | title = Misconceptions about the Big Bang | journal = Scientific American | volume = 292 | issue = 3 | pages = 36–45 | doi = 10.1038/scientificamerican0305-36 | bibcode = 2005SciAm.292c..36L }}</ref> This redshift corresponds to a shift in average temperature from 3000K down to 3K.<ref>{{cite journal|last1=Gawiser|first1=E.|last2=Silk|first2=J.|date=2000|title=The cosmic microwave background radiation|journal=[[Physics Reports]]|volume=333–334|issue=2000|pages=245–267|doi=10.1016/S0370-1573(00)00025-9|arxiv=astro-ph/0002044|bibcode = 2000PhR...333..245G |citeseerx=10.1.1.588.3349|s2cid=15398837}}</ref>
The yet-to-be-observed first light from the oldest [[Population III stars]], not long after atoms first formed and the CMB ceased to be absorbed almost completely, may have redshifts in the range of {{math|20 < ''z'' < 100}}.<ref>{{cite journal|bibcode=2006MNRAS.373L..98N|arxiv = astro-ph/0604050 |doi = 10.1111/j.1745-3933.2006.00251.x|title=The first stars in the Universe|date=2006|last1=Naoz|first1=S.|last2=Noter|first2=S.|last3=Barkana|first3=R.|journal=Monthly Notices of the Royal Astronomical Society: Letters|volume=373|issue = 1 |pages=L98–L102 |doi-access = free |s2cid = 14454275 }}</ref> Other high-redshift events predicted by physics but not presently observable are the [[cosmic neutrino background]] from about two seconds after the Big Bang (and a redshift in excess of {{math|''z'' > 10{{sup|10}}}})<ref>{{cite journal|bibcode=2006PhR...429..307L|arxiv = astro-ph/0603494 |doi = 10.1016/j.physrep.2006.04.001|title=Massive neutrinos and cosmology|date=2006|last1=Lesgourgues|first1=J|last2=Pastor|first2=S|journal=Physics Reports|volume=429|issue=6|pages=307–379 |s2cid = 5955312 }}</ref> and the cosmic [[gravitational wave background]] emitted directly from [[inflation (cosmology)|inflation]] at a redshift in excess of {{math|''z'' > 10{{sup|25}}}}.<ref>{{cite journal|bibcode=2005PhyU...48.1235G|arxiv = gr-qc/0504018 |doi = 10.1070/PU2005v048n12ABEH005795|title=Relic gravitational waves and cosmology|date=2005|last1=Grishchuk|first1=Leonid P|journal=Physics-Uspekhi|volume=48|issue=12|pages=1235–1247 |s2cid = 11957123 }}</ref>

In June 2015, astronomers reported evidence for [[Stellar population#Population III stars|Population III stars]] in the [[Cosmos Redshift 7]] [[galaxy]] at {{math|''z'' {{=}} 6.60}}. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of [[chemical element]]s heavier than [[hydrogen]] that are needed for the later formation of [[planet]]s and [[life]] as we know it.<ref name="AJ-20150604">{{cite journal |last1=Sobral |first1=David |last2=Matthee |first2=Jorryt |last3=Darvish |first3=Behnam |last4=Schaerer |first4=Daniel |last5=Mobasher |first5=Bahram |last6=Röttgering |first6=Huub J. A. |last7=Santos |first7=Sérgio |last8=Hemmati |first8=Shoubaneh |title=Evidence For POPIII-Like Stellar Populations In The Most Luminous LYMAN-α Emitters At The Epoch Of Re-Ionisation: Spectroscopic Confirmation |date=4 June 2015 |journal=[[The Astrophysical Journal]] |doi=10.1088/0004-637x/808/2/139 |bibcode=2015ApJ...808..139S |volume=808 |issue=2 |page=139|arxiv=1504.01734|s2cid=18471887 }}</ref><ref name="NYT-20150617">{{cite news |last=Overbye |first=Dennis |author-link=Dennis Overbye |title=Astronomers Report Finding Earliest Stars That Enriched Cosmos |url=https://www.nytimes.com/2015/06/18/science/space/astronomers-report-finding-earliest-stars-that-enriched-cosmos.html |date=17 June 2015 |work=[[The New York Times]] |access-date=17 June 2015 }}</ref>