Editing Habitable zone (section)

==History==
[[File:Maunder Edward Walter.jpg|thumb|[[Edward Walter Maunder]], British astronomer, who introduced the concept of habitable zones]]
An estimate of the range of distances from the Sun allowing the existence of liquid water appears in [[Isaac Newton|Newton's]] ''[[Philosophiæ Naturalis Principia Mathematica|Principia]]'' (Book III, Section 1, corol. 4).<ref>{{cite book |last1=Newton |first1=Isaac |author-link=Isaac Newton |title=Philosophiae Naturalis Principia Mathematica |date=1729 |page=739 |edition=3rd |url=https://www.17centurymaths.com/contents/newton/book3s1.pdf#page=18 |archive-url=https://web.archive.org/web/20231113064651/http://17centurymaths.com/contents/newton/book3s1.pdf#page=18 |archive-date=13 November 2023 |chapter=Book III - Section I - Proposition VIII - Corol. 4 |url-status=live }}</ref> The philosopher [[Louis Claude de Saint-Martin]] speculated in his 1802 work ''Man: His True Nature and Ministry'', "... we may presume, that, being susceptible of vegetation, it [the Earth] has been placed, in the series of planets, in the rank which was necessary, and at exactly the right distance from the sun, to accomplish its secondary object of vegetation; and from this we might infer that the other planets are either too near or too remote from the sun, to vegetate."<ref>{{cite book |last1= de Saint-Martin |first1= Louis Claude |author-link= Louis Claude de Saint-Martin  |title= Man: His True Nature and Ministry |date=1802 |page=78}}</ref>

Possibly the earliest use of the term habitable zone was in 1913,<ref>{{cite book |last=Lorenz |first=Ralph |date=2019|title=Exploring Planetary Climate: A History of Scientific Discovery on Earth, Mars, Venus, and Titan|publisher=Cambridge University Press |page= 53 |isbn=978-1108471541}}</ref> by [[Edward Maunder]] in his book "Are The Planets Inhabited?".<ref>{{cite journal | journal=Research Notes of the American Astronomical Society |title=Maunder's Work on Planetary Habitability in 1913: Early Use of the term "Habitable Zone" and a "Drake Equation" Calculation|year=2020 |last=Lorenz |first=Ralph |volume=4 |issue=6 |page=79|doi=10.3847/2515-5172/ab9831|bibcode=2020RNAAS...4...79L|s2cid=219930646 |doi-access=free }}</ref> [[Hubertus Strughold]]'s 1953 treatise ''The Green and the Red Planet: A Physiological Study of the Possibility of Life on Mars'' used the term "ecosphere" and referred to various "zones" in which life could emerge.<ref name=huggett-1995>{{cite book |url=https://archive.org/details/geoecologyevolut0000hugg |url-access=registration |title=Geoecology: An Evolutionary Approach |publisher=Routledge, Chapman & Hall |author=Huggett, Richard J. |date=1995 |page=[https://archive.org/details/geoecologyevolut0000hugg/page/10 10] |isbn=978-0-415-08689-9}}</ref><ref name=strughold-1953>{{cite book |url=https://books.google.com/books?id=zNbPAAAAMAAJ |title=The Green and Red Planet: A Physiological Study of the Possibility of Life on Mars |publisher=University of New Mexico Press |author=Strughold, Hubertus |date=1953}}</ref> In the same year, [[Harlow Shapley]] wrote "Liquid Water Belt", which described the same concept in further scientific detail. Both works stressed the importance of liquid water to life.<ref name="Kasting2010">{{cite book|author=Kasting, James|title=How to Find a Habitable Planet|url=https://books.google.com/books?id=xPqEeB-SRvUC|access-date=4 May 2013|date=2010|publisher=Princeton University Press|isbn=978-0-691-13805-3|page=127}}</ref> [[Su-Shu Huang]], an American astrophysicist argued in 1960 that circumstellar habitable zones, and by extension extraterrestrial life, would be uncommon in [[multiple star system]]s, given the gravitational instabilities of those systems.<ref name=kasting-1993>{{cite journal |title=Habitable Zones around Main Sequence Stars |author1=Kasting, James F. |author2=Whitmire, Daniel P. |author3=Reynolds, Ray T. |journal=Icarus |date=January 1993 |volume=101 |issue=1 |pages=108–118 |doi=10.1006/icar.1993.1010 |bibcode=1993Icar..101..108K |pmid=11536936}}</ref><ref name=huang-1966>{{cite book |url=https://books.google.com/books?id=D0UrAAAAYAAJ |title=Extraterrestrial life: An Anthology and Bibliography |publisher=National Academy of Sciences |author=Huang, Su-Shu |date=1966 |location=Washington, D. C. |pages=87–93 |others=National Research Council (U.S.). Study Group on Biology and the Exploration of Mars|bibcode=1966elab.book.....S }}</ref><ref name=huang-1960>{{cite journal |title=Life-Supporting Regions in the Vicinity of Binary Systems |author=Huang, Su-Shu |journal=Publications of the Astronomical Society of the Pacific |date=April 1960 |volume=72 |issue=425 |pages=106–114 |bibcode=1960PASP...72..106H |doi=10.1086/127489|doi-access=free }}</ref>

The concept of habitable zones was further developed in 1964 by [[Stephen H. Dole]] in his book ''Habitable Planets for Man'', in which he discussed the concept of the circumstellar habitable zone as well as various other determinants of planetary habitability, eventually estimating the number of habitable planets in the Milky Way to be about 600&nbsp; million.<ref name="dole-1964"/> At the same time, science-fiction author [[Isaac Asimov]] introduced the concept of a circumstellar habitable zone to the general public through his various explorations of [[space colonization]].<ref name=gilster-2004>{{cite book |url=https://archive.org/details/springer_10.1007-978-1-4757-3894-0 |title=Centauri Dreams: Imagining and Planning Interstellar Exploration |publisher=Springer |author=Gilster, Paul |date=2004 |isbn=978-0-387-00436-5 |page=[https://archive.org/details/springer_10.1007-978-1-4757-3894-0/page/n51 40]}}</ref> The term "[[Goldilocks principle|Goldilocks zone]]" emerged in the 1970s, referencing specifically a region around a star whose temperature is "just right" for water to be present in the liquid phase.<ref name=nasa-2003>{{cite press release |url=https://science.nasa.gov/science-news/science-at-nasa/2003/02oct_goldilocks/ |title=The Goldilocks Zone |publisher=NASA |date=October 2, 2003 |access-date=April 22, 2013 |archive-date=August 29, 2011 |archive-url=https://web.archive.org/web/20110829081900/http://science.nasa.gov/science-news/science-at-nasa/2003/02oct_goldilocks/ |url-status=dead }}</ref> In 1993, astronomer [[James Kasting]] introduced the term "circumstellar habitable zone" to refer more precisely to the region then (and still) known as the habitable zone.<ref name=kasting-1993 /> Kasting was the first to present a detailed model for the habitable zone for exoplanets.<ref name="F. Kasting, D. P 1993"/><ref name="Seager 2013">{{cite journal |title=Exoplanet Habitability |journal=Science |year=2013 |last=Seager |first=Sara |s2cid=206546351 |volume=340 |issue=577 |pages=577–581 |doi=10.1126/science.1232226 |pmid=23641111 |bibcode=2013Sci...340..577S }}</ref>

An update to the habitable zone concept came in 2000 when astronomers [[Peter Ward (paleontologist)|Peter Ward]] and [[Donald Brownlee]] introduced the idea of the "[[galactic habitable zone]]", which they later developed with [[Guillermo Gonzalez (astronomer)|Guillermo Gonzalez]].<ref name="Rare Earth" /><ref name=gonzalez-2001>{{cite journal |title=The Galactic Habitable Zone I. Galactic Chemical Evolution |author1=Gonzalez, Guillermo |author2=Brownlee, Donald |author3=Ward, Peter |journal=Icarus |date=July 2001 |volume=152 |issue=1 |pages=185–200 |doi=10.1006/icar.2001.6617 |arxiv=astro-ph/0103165|bibcode = 2001Icar..152..185G |s2cid=18179704 }}</ref> The galactic habitable zone, defined as the region where life is most likely to emerge in a galaxy, encompasses those regions close enough to a [[Central massive object|galactic center]] that stars there are enriched with [[metallicity|heavier elements]], but not so close that star systems, planetary orbits, and the emergence of life would be frequently disrupted by the intense radiation and enormous gravitational forces commonly found at galactic centers.<ref name="Rare Earth"/>

Subsequently, some astrobiologists propose that the concept be extended to other solvents, including dihydrogen, sulfuric acid, dinitrogen, formamide, and methane, among others, which would support hypothetical life forms that use an [[alternative biochemistry]].<ref name=villard-2011 /> In 2013, further developments in habitable zone concepts were made with the proposal of a circum- ''planetary'' habitable zone, also known as the "habitable edge", to encompass the region around a planet where the orbits of natural satellites would not be disrupted, and at the same time tidal heating from the planet would not cause liquid water to boil away.<ref name=hadhazy-2013>{{cite news |url=http://www.astrobio.net/exclusive/5364/the-habitable-edge-of-exomoons |title=The 'Habitable Edge' of Exomoons |work=Astrobiology Magazine |date=April 3, 2013 |agency=NASA |access-date=April 22, 2013 |author=Hadhazy, Adam |url-status=dead |archive-date=May 2, 2013 |archive-url=https://web.archive.org/web/20130502064349/http://www.astrobio.net/exclusive/5364/the-habitable-edge-of-exomoons }}</ref>

It has been noted that the current term of 'circumstellar habitable zone' poses confusion as the name suggests that planets within this region will possess a habitable environment.<ref name='Tasker Nature 2017'>{{Cite journal|last1=Tasker|first1=Elizabeth|last2=Tan|first2=Joshua|last3=Heng|first3=Kevin|last4=Kane|first4=Stephen|last5=Spiegel|first5=David|last6=Brasser|first6=Ramon|last7=Casey|first7=Andrew|last8=Desch|first8=Steven|last9=Dorn|first9=Caroline|last10=Hernlund|first10=John|last11=Houser|first11=Christine|date=2017-02-02|title=The language of exoplanet ranking metrics needs to change|journal=Nature Astronomy|language=en|volume=1|issue=2|pages=0042|doi=10.1038/s41550-017-0042|arxiv=1708.01363|bibcode=2017NatAs...1E..42T|s2cid=118952886}}</ref><ref name='Patel MIT 2019'/> However, surface conditions are dependent on a host of different individual properties of that planet.<ref name='Tasker Nature 2017'/><ref name='Patel MIT 2019'>{{cite web|url=https://www.technologyreview.com/s/614449/no-one-agrees-what-it-means-for-a-planet-to-be-habitable/|title=No one agrees what it means for a planet to be "habitable"|author=Neel V. Patel|publisher=MIT Technology Review|date=2 October 2019|quote="surface conditions are dependent on a host of different individual properties of that planet, such as internal and geological processes, magnetic field evolution, climate, atmospheric escape, rotational effects, tidal forces, orbits, star formation and evolution, unusual conditions like binary star systems, and gravitational perturbations from passing bodies."}}</ref> This misunderstanding is reflected in excited reports of 'habitable planets'.<ref name=":0">{{Cite web|url=http://theconversation.com/until-we-get-better-tools-excited-reports-of-habitable-planets-need-to-come-back-down-to-earth-72425|title=Until we get better tools, excited reports of 'habitable planets' need to come back down to Earth| last=Tan| first=Joshua| website=The Conversation |date=8 February 2017 |language=en| access-date=2019-10-21}}</ref><ref name='Sci News Oct2019'>{{Cite web| url=https://www.sciencenews.org/article/why-just-being-habitable-zone-doesnt-make-exoplanets-livable| title=Why just being in the habitable zone doesn't make exoplanets livable| date=2019-10-04|website=Science News| language=en-US| access-date=2019-10-21}}</ref><ref>[https://blogs.scientificamerican.com/observations/no-the-exoplanet-k2-18b-is-not-habitable/ No, the Exoplanet K2-18b Is Not Habitable. News outlets that said otherwise are just crying wolf—but they're not the only ones at fault.] Laura Kreidberg, ''Scientific American''. 23 September 2019.</ref> Since it is completely unknown whether conditions on these distant HZ worlds could host life, different terminology is needed.<ref name='Patel MIT 2019'/><ref name='Sci News Oct2019'/><ref name='Tasker Sci Am 2019'>{{Cite web| url=https://blogs.scientificamerican.com/observations/lets-lose-the-term-habitable-zone-for-exoplanets/| title=Let's Lose the Term "Habitable Zone" for Exoplanets| last=Tasker|first=Elizabeth| website=Scientific American Blog Network| language=en| access-date=2019-10-21}}</ref><ref name='Ruhner 2019'>{{Cite web|url=https://www.numerama.com/sciences/562381-exoplanetes-faut-il-en-finir-avec-la-zone-dhabitabilite.html| title=Exoplanètes: faut-il en finir avec la "zone d'habitabilité"? - Sciences| last=Ruher| first=Hugo| date=2019-10-20| website=Numerama| language=fr-FR|access-date=2019-10-21}}</ref>