Editing Cosmological constant (section)

== References ==
=== Footnotes ===
{{reflist|30em|refs=
<ref name="CC Definition">It may well be that dark energy is explained by a static cosmological constant, or that this mysterious energy is not constant at all and has changed over time, as in the case with quintessence, see for example:
* "Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Λ; nowadays the concept is termed dark energy or quintessence." {{harvp|Peebles|Ratra|2003|p=1}}
* "It would then appear that the cosmological fluid is dominated by some sort of fantastic energy density, which has negative pressure, and has just begun to play an important role today. No convincing theory has yet been constructed to explain this state of affairs, although cosmological models based on a dark energy component, such as the cosmological constant ({{math|Λ}}) or quintessence (Q), are leading candidates." {{harvp|Caldwell|2002|p=2}}
</ref>
<ref name="Rugh 2001 3">{{harvp|Rugh|Zinkernagel|2001|p=3}}</ref>
<ref name="Λ = 0?">On the Cosmological Constant being thought to have zero value see for example:
* "Since the cosmological upper bound on {{abs|{{angle bracket|''ρ''}} + ''λ''/8''πG''}} was vastly less than any value expected from particle theory, most particle theorists simply assumed that for some unknown reason this quantity was zero." {{harvp|Weinberg|1989|p=3}}
* "An epochal astronomical discovery would be to establish by convincing observation that Λ is nonzero." {{harvp|Carroll|Press|Turner|1992|p=500}}
* "Before 1998, there was no direct astronomical evidence for Λ and the observational upper bound was so strong (Λ&nbsp;<&nbsp;10<sup>−120</sup>&nbsp;Planck units) that many particle physicists suspected that some fundamental principle must force its value to be precisely zero." {{harvp|Barrow|Shaw|2011|p=1}}
* "The only other natural value is Λ&nbsp;=&nbsp;0. If Λ really is tiny but not zero, it adds a most stimulating though enigmatic clue to physics to be discovered." {{harvp|Peebles|Ratra|2003|p=333}}
</ref>
<ref name="1998 Discovery">See for example:
* "This is the independent result of two teams. [[Supernova Cosmology Project]] ({{harvp|Perlmutter et al.|1999}}; also see {{harvp|Perlmutter et al.|1998}}) and the [[High-Z Supernova Search Team]] ({{harvp|Riess et al.|1998}}; also see {{harvp|Schmidt et al.|1998}})" {{harvp|Weinberg|2015|p=376}}
</ref>
<ref name="Biggest Blunder">There is some debate over whether Einstein labelled the cosmological constant his "biggest blunder", with all references being traced back to a single person: [[George Gamow]]. (See {{harvs|txt|last1=Gamow|year1=1956|year2=1970}}.) For example:
* "Astrophysicist and author Mario Livio can find no documentation that puts those words into Einstein's mouth (or, for that matter, his pen). Instead, all references eventually lead back to one man—physicist George Gamow—who reported Einstein's use of the phrase in two sources: His posthumously published autobiography ''My World Line'' (1970) and a ''Scientific American'' article from September&nbsp;1956." {{harvp|Rosen|2013}}
* " We also find it quite plausible that Einstein made such a statement to Gamow in particular. We conclude that there is little doubt that Einstein came to view the introduction of the cosmological constant a serious error, and that it is very plausible that he labelled the term his "biggest blunder" on at least one occasion". {{harvp|O'Raifeartaigh|Mitton|2018|p=1}}
</ref>
<ref name="CC Problem">See for example:
* "This gives an answer about 120&nbsp;orders of magnitude higher than the upper limits on Λ set by cosmological observations. This is probably the worst theoretical prediction in the history of physics!" {{harvp|Hobson|Efstathiou|Lasenby|2006|p=187}}
* "This, as we will see later, is approximately 120&nbsp;orders of magnitude larger than what is allowed by observation." {{harvp|Carroll|Press|Turner|1992|p=503}}
* "Theoretical expectations for the cosmological constant exceed observational limits by some 120&nbsp;orders of magnitude." {{harvp|Weinberg|1989|p=1}}</ref>
<ref name="CC Problem 3">See for example:
* "the vacuum holds the key to a full understanding of nature" {{harvp|Davies|1985|p=104}}
* "The theoretical problem of explaining the cosmological constant is one of the greatest challenges of theoretical physics. It is most likely that we require a fully developed theory of quantum gravity (perhaps superstring theory) before we can understand Λ." {{harvp|Hobson|Efstathiou|Lasenby|2006|p=188}}</ref>
}}

=== Bibliography ===
==== Primary literature ====
{{refbegin|30em}}
* {{cite journal |last1=Baker |first1=J. C. |last2=Grainge |first2=K. |last3=Hobson|first3=M.P. |last4=Jones |first4=M.E. |last5=Kneissl |first5=R. |last6=Lasenby |first6=A.N. |last7=O'Sullivan |first7=C.M. M.|last8=Pooley |first8=G. |last9=Rocha |first9=G. |last10=Saunders |first10=R. |last11=Scott |first11=P.F. |last12=Waldram |first12=E.M. |title=Detection of cosmic microwave background structure in a second field with the Cosmic Anisotropy Telescope |journal=Monthly Notices of the Royal Astronomical Society |volume=308 |issue=4 |year=1999 |pages=1173–1178 |issn=0035-8711 |doi=10.1046/j.1365-8711.1999.02829.x |doi-access=free |arxiv=astro-ph/9904415 |bibcode = 1999MNRAS.308.1173B |s2cid=10867413 |display-authors=etal |ref={{harvid|Baker et al.|1999}} }}
* {{cite journal |last1=Dyson |first1=L. |last2=Kleban |first2=M. |last3=Susskind |first3=L. |title=Disturbing Implications of a Cosmological Constant |journal=Journal of High Energy Physics |volume=2002 |issue=10 |year=2002 |pages=011 |issn=1029-8479 |doi=10.1088/1126-6708/2002/10/011 |bibcode=2002JHEP...10..011D |arxiv=hep-th/0208013 |s2cid=2344440 }}
* {{cite journal |last1=Einstein |first1=A. |author-link1=Albert Einstein |title=Kosmologische Betrachtungen zur allgemeinen Relativitätstheorie |year=1917 |url=http://einstein-annalen.mpiwg-berlin.mpg.de/related_texts/sitzungsberichte |journal=[[Prussian Academy of Sciences|Sitzungsberichte der Königlich Preußischen Akademie der Wissenschaften]] |volume=part 1 |pages=142–152 |location=Berlin, DE |bibcode=1917SPAW.......142E |access-date=2014-11-15 |archive-url=https://web.archive.org/web/20190321062928/http://einstein-annalen.mpiwg-berlin.mpg.de/related_texts/sitzungsberichte |archive-date=2019-03-21 |url-status=dead }}
* {{cite journal |last1=Gamow |first1=G. |author-link1=George Gamow |title=The evolutionary universe |journal=Scientific American |year=1956 |volume=195 |issue=3 |pages=136–156 |jstor=24941749 |doi=10.1038/scientificamerican0956-136 |bibcode=1956SciAm.195c.136G }}
* {{cite book |last1=Gamow |first1=G. |author-link1=George Gamow |title=My World Line: An informal autobiography |year=1970 |publisher=Viking Press |location=New York, NY |isbn=978-0-670-50376-6 |lccn=79094855 |oclc=70097 }}
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* {{cite journal |last1=Perlmutter |first1=S. |last2=Aldering |first2=G. |last3=Goldhaber |first3=G. |last4=Knop |first4=R.A. |last5=Nugent |first5=P. |last6=Castro |first6=P.G. |last7=Deustua |first7=S. |last8=Fabbro|first8=S. |last9=Goobar|first9=A. |last10=Groom |first10=D.E. |last11=Hook |first11=I.M. |last12=Kim |first12=A.G. |last13=Kim |first13=M.Y. |last14=Lee |first14=J.C. |last15=Nunes |first15=N.J. |last16=Pain |first16=R. |last17=Pennypacker |first17=C.R. |last18=Quimby |first18=R. |last19=Lidman |first19=C. |last20=Ellis |first20=R.S. |last21=Irwin |first21=M. |last22=McMahon |first22=R.G. |last23=Ruiz-Lapuente |first23=P. |last24=Walton |first24=N. |last25=Schaefer |first25=B. |last26=Boyle |first26=B.J. |last27=Filippenko |first27=A.V. |last28=Matheson |first28=T. |last29=Fruchter |first29=A.S. |last30=Panagia |first30=N. |last31=Newberg |first31=H.J.M. |last32=Couch |first32=W.J. |author33=The Supernova Cosmology Project |title=Measurements of Ω and Λ from 42&nbsp;high-redshift supernovae |journal=The Astrophysical Journal |volume=517 |issue=2 |year=1999 |pages=565–586 |issn=0004-637X |doi=10.1086/307221 |bibcode=1999ApJ...517..565P |arxiv=astro-ph/9812133 |s2cid=118910636 |ref={{harvid|Perlmutter et al.|1999}} }}
* {{cite journal |last1=Riess |first1=A.G. |last2=Filippenko |first2=A.V. |last3=Challis |first3=P. |last4=Clocchiatti |first4=A. |last5=Diercks |first5=A. |last6=Garnavich |first6=P.M. |last7=Gilliland |first7=R.L. |last8=Hogan|first8=C.J. |last9=Jha|first9=S. |last10=Kirshner |first10=R.P. |last11=Leibundgut|first11=B. |last12=Phillips |first12=M.M. |last13=Reiss |first13=D. |last14=Schmidt |first14=B.P. |last15=Schommer |first15=R.A. |last16=Smith |first16=R.C. |last17=Spyromilio |first17=J. |last18=Stubbs |first18=C. |last19=Suntzeff |first19=N.B. |last20=Tonry |first20=J. |title=Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant |journal=The Astronomical Journal |volume=116 |issue=3 |year=1998 |pages=1009–1038 |issn=0004-6256 |doi=10.1086/300499|bibcode=1998AJ....116.1009R |arxiv=astro-ph/9805201 |s2cid=15640044 |ref={{harvid|Riess et al.|1998}} }}
* {{cite journal |last1=Schmidt |first1=B.P. |last2=Suntzeff |first2=N.B. |last3=Phillips |first3=M.M. |last4=Schommer |first4=R.A. |last5=Clocchiatti |first5=A. |last6=Kirshner |first6=R.P. |last7=Garnavich |first7=P. |last8=Challis|first8=P. |last9=Leibundgut |first9=B. |last10=Spyromilio |first10=J. |last11=Riess |first11=A.G. |last12=Filippenko |first12=A.V. |last13=Hamuy |first13=M. |last14=Smith |first14=R. C. |last15=Hogan |first15=C. |last16=Stubbs |first16=C. |last17=Diercks |first17=A.|last18=Reiss |first18=D. |last19=Gilliland |first19=R. |last20=Tonry |first20=J. |last21=Maza |first21=J. |last22=Dressler |first22=A. |last23=Walsh |first23=J. |last24=Ciardullo |first24=R. |title=The High-Z Supernova Search: Measuring Cosmic Deceleration and Global Curvature of the Universe Using Type Ia Supernovae |journal=The Astrophysical Journal |volume=507 |issue=1 |year=1998 |pages=46–63 |issn=0004-637X |doi=10.1086/306308|bibcode=1998ApJ...507...46S |arxiv=astro-ph/9805200 |s2cid=15762698 |ref={{harvid|Schmidt et al.|1998}} }}
* {{cite journal |author1=The Planck Collaboration |title=Planck 2015 results I. Overview of products and scientific results |journal=Astronomy & Astrophysics |date=2016|volume=594 |pages=A1 |doi=10.1051/0004-6361/201527101 |arxiv=1502.01582 |bibcode=2016A&A...594A...1P |s2cid=119213675 |ref={{harvid|The Planck Collaboration|2015a}} }}
* {{cite journal |author1=Planck Collaboration |title=Planck 2015 results. XIII. Cosmological parameters |journal=Astronomy & Astrophysics |volume=594 |year=2016 |pages=A13 |issn=0004-6361 |doi=10.1051/0004-6361/201525830|bibcode=2016A&A...594A..13P|arxiv=1502.01589 |s2cid=119262962 |ref={{harvid|The Planck Collaboration|2015b}} }}
* {{cite journal |author1=The Planck Collaboration |title=Planck 2018 results. VI. Cosmological parameters |journal=Astronomy and Astrophysics |year=2020 |volume=641 |pages=A6 |doi=10.1051/0004-6361/201833910 |arxiv=1807.06209 |bibcode=2020A&A...641A...6P|s2cid=119335614 }}
* {{cite journal |last=Weinberg |first=S. |title=Anthropic Bound on the Cosmological Constant |journal=Phys. Rev. Lett. |volume=59 |pages=2607–2610 |bibcode=1987PhRvL..59.2607W |doi=10.1103/PhysRevLett.59.2607 |year=1987 |pmid=10035596 |issue=22 }}
{{refend}}

==== Secondary literature: news, popular science articles & books ====
{{refbegin|30em}}
* {{cite journal|last1=Abbott|first1=Larry|s2cid=30023659|author-link1=Larry Abbott|title=The Mystery of the Cosmological Constant|journal=Scientific American|volume=258|issue=5|year=1988|pages=106–113|issn=0036-8733|doi=10.1038/scientificamerican0588-106|bibcode=1988SciAm.258e.106A}}
* {{cite journal|last1=Barrow|first1=J. D.|last2=Webb|first2=J. K.|title=Inconstant Constants|journal=Scientific American|volume=292|issue=6|year=2005|pages=56–63|issn=0036-8733|doi=10.1038/scientificamerican0605-56|pmid=15934653|bibcode=2005SciAm.292f..56B|url=http://phys.unsw.edu.au/~jkw/hons/barr_webb_sciam11.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://phys.unsw.edu.au/~jkw/hons/barr_webb_sciam11.pdf |archive-date=2022-10-09 |url-status=live}}
* {{cite journal|last1=Brumfiel|first1=G.|title=A constant problem|journal=Nature|volume=448|issue=7151|year=2007|pages=245–248|issn=0028-0836|doi=10.1038/448245a|pmid=17637631|bibcode=2007Natur.448..245B|s2cid=4428576|url=http://hosting.astro.cornell.edu/academics/courses/astro1109/readings/AConstantProblem.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://hosting.astro.cornell.edu/academics/courses/astro1109/readings/AConstantProblem.pdf |archive-date=2022-10-09 |url-status=live|doi-access=free}}
* {{cite book|last1=Davies|first1=P. C. W.|author-link1=Paul Davies|title=Superforce: The Search for a Grand Unified Theory of Nature|date=1985|publisher=Simon and Schuster|location=New York|isbn=978-0-671-47685-4|url=https://books.google.com/books?id=Bna5p4vJtucC|lccn=84005473|oclc=12397205}}
* {{cite journal|last1=Hogan|first1=J.|title=Welcome to the dark side|journal=Nature|volume=448|issue=7151|year=2007|pages=240–245|issn=0028-0836|doi=10.1038/448240a|pmid=17637630|url=http://pa.brown.edu/articles/Nature_Vol448_20070719_UnseenUniverse.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://pa.brown.edu/articles/Nature_Vol448_20070719_UnseenUniverse.pdf |archive-date=2022-10-09 |url-status=live|bibcode=2007Natur.448..240H|s2cid=4415960|doi-access=free}}
* {{cite journal |last1=O'Raifeartaigh |first1=C. |last2=Mitton |first2=S. |title=Einstein's "biggest blunder" – interrogating the legend |journal=Physics in Perspective |volume=20 |issue=4 |pages=318–341 |date=2018 |arxiv=1804.06768 |doi=10.1007/s00016-018-0228-9 |s2cid=119097586 }}
* {{cite web |last1=Redd |first1=N. T. |title=What is Dark Energy? |url=https://www.space.com/20929-dark-energy.html |website=space.com |archive-url=https://archive.today/20160519162257/http://www.space.com/20929-dark-energy.html |archive-date=19 May 2016 |date=2013 |access-date=28 October 2018 |url-status=live }}
* {{cite web |last1=Rosen |first1=R. J. |title=Einstein Likely Never Said One of His Most Oft-Quoted Phrases |url=https://www.theatlantic.com/technology/archive/2013/08/einstein-likely-never-said-one-of-his-most-oft-quoted-phrases/278508/ |website=theatlantic.com |publisher=The Atlantic |archive-url=https://archive.today/20130810062508/http://www.theatlantic.com/technology/archive/2013/08/einstein-likely-never-said-one-of-his-most-oft-quoted-phrases/278508/ |archive-date=10 August 2013 |date=2013 |access-date=6 March 2017 |url-status=live }}
{{refend}}

==== Secondary literature: review articles, monographs and textbooks ====
{{refbegin|30em}}
* {{cite journal|last1=Barrow|first1=J. D.|last2=Shaw|first2=D. J.|title=The value of the cosmological constant|journal=General Relativity and Gravitation|volume=43|issue=10|year=2011|pages=2555–2560|issn=0001-7701|doi=10.1007/s10714-011-1199-1|bibcode=2011GReGr..43.2555B|arxiv=1105.3105|s2cid=55125081}}
* {{cite journal|last1=Caldwell|first1=R. R.|title=A phantom menace? Cosmological consequences of a dark energy component with super-negative equation of state|journal=Physics Letters B|volume=545|issue=1–2|year=2002|pages=23–29|issn=0370-2693|doi=10.1016/S0370-2693(02)02589-3|bibcode=2002PhLB..545...23C|arxiv=astro-ph/9908168|s2cid=9820570}}
* {{cite journal|last1=Carroll|first1=S. M.|author-link1=Sean M. Carroll|last2=Press|first2=W. H.|author-link2=William H. Press|last3=Turner|first3=E. L.|title=The Cosmological Constant|journal=Annual Review of Astronomy and Astrophysics|volume=30|issue=1|year=1992|pages=499–542|issn=0066-4146|doi=10.1146/annurev.aa.30.090192.002435|pmid=28179856|pmc=5256042|bibcode=1992ARA&A..30..499C|url=https://preposterousuniverse.com/wp-content/uploads/cpt92.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://preposterousuniverse.com/wp-content/uploads/cpt92.pdf |archive-date=2022-10-09 |url-status=live}}
* {{cite book |last1=Hobson |first1=M. P. |last2=Efstathiou |first2=G. P. |last3=Lasenby |first3=A. N. |title=General Relativity: An Introduction for Physicists |date=2006 |publisher=Cambridge University Press |location=Cambridge |isbn=978-0-521-82951-9 |edition=2014 |url=https://books.google.com/books?id=5dryXCWR7EIC|oclc=903178203|lccn=2006277059}}
* {{cite journal|last1=Joyce|first1=A.|last2=Jain|first2=B.|last3=Khoury|first3=J.|last4=Trodden|first4=M.|title=Beyond the cosmological standard model|journal=Physics Reports|volume=568|year=2015|pages=1–98|issn=0370-1573|doi=10.1016/j.physrep.2014.12.002|bibcode=2015PhR...568....1J|arxiv=1407.0059|s2cid=119187526}}
* {{cite journal|last1=Peebles|first1=P. J. E.|author-link1=Jim Peebles|last2=Ratra|first2=B.|author-link2=Bharat Ratra|title=The Cosmological Constant and Dark Energy|journal=Reviews of Modern Physics|volume=75|issue=2|year=2003|pages=559–606|issn=0034-6861|doi=10.1103/RevModPhys.75.559|bibcode=2003RvMP...75..559P|arxiv=astro-ph/0207347|s2cid=118961123}}
* {{cite journal | last1=Rugh | first1=S | title=The Quantum Vacuum and the Cosmological Constant Problem | journal=Studies in History and Philosophy of Modern Physics| volume=33 | issue=4 | pages=663–705 | doi=10.1016/S1355-2198(02)00033-3 | date=2001 | last2=Zinkernagel | first2=H. | bibcode=2002SHPMP..33..663R| arxiv=hep-th/0012253 | s2cid=9007190 }}
* {{cite book |last1=Ryden |first1=B. S. |title=Introduction to Cosmology |date=2003 |publisher=Addison-Wesley |location=San Francisco |isbn=978-0-8053-8912-8|oclc=50478401|lccn=2002013176}}
* {{cite book |last1=Vilenkin |first1=A. |author-link1=Alexander Vilenkin |title=Many worlds in one: The Search For Other Universes |date=2006 |publisher=Hill and Wang |location=New York |isbn=978-0-8090-9523-0 |oclc=799428013 |lccn=2005027057 |url-access=registration |url=https://archive.org/details/manyworldsinoneo00vile }}
* {{cite journal|last1=Weinberg|first1=S.|author-link1=Steven Weinberg|title=The Cosmological Constant Problem|journal=Reviews of Modern Physics|volume=61|issue=1|year=1989|pages=1–23|issn=0034-6861|doi=10.1103/RevModPhys.61.1|bibcode=1989RvMP...61....1W|url=https://repositories.lib.utexas.edu/bitstream/2152/61094/1/Weinberg_1989.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://repositories.lib.utexas.edu/bitstream/2152/61094/1/Weinberg_1989.pdf |archive-date=2022-10-09 |url-status=live|hdl=2152/61094|s2cid=122259372 |hdl-access=free}}
* {{cite book |last1=Weinberg |first1=S. |author-link1=Steven Weinberg |title=Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature. |date=1992 |publisher=Pantheon Books |location=New York |isbn=978-0-679-74408-5|lccn=93030534|oclc=319776354}}
* {{cite book|last1=Weinberg|first1=S.|author-link1=Steven Weinberg|title=Lectures on Quantum Mechanics|date=2015|publisher=Cambridge University Press|location=Cambridge|isbn=978-1-107-11166-0|edition=2nd|lccn=2015021123|oclc= 910664598}}
{{refend}}