Cosmogony: Difference between revisions
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{{Short description|Theory or model concerning the origin of the universe}} | {{Short description|Theory or model concerning the origin of the universe}} | ||
{{hatnote group|{{ | {{hatnote group|{{about||the Björk song|Cosmogony (song)|the Obscura album|Cosmogenesis (album)}}}} | ||
{{Use dmy dates|date=September 2019}} | {{Use dmy dates|date=September 2019}} | ||
[[File:Universe expansion2.png|thumb|The [[Big Bang]] theory of modern cosmology postulates the universe began as a dense hot fire ball.]] | |||
'''Cosmogony''', also spelled as '''cosmogeny''',<ref>{{Cite journal |journal=Nature |volume=340 |issue=6228 |language=en |issn=0028-0836 |date=July 1989 |pages=17–18 |doi=10.1038/340017a0 |url=https://www.nature.com/articles/340017a0 |title=The dichotomy of cosmogeny |first=Jonathan J. |last=Halliwell|url-access=subscription }}</ref> or '''cosmogenesis'''<ref>{{Cite book |isbn=978-0-19-802221-3 |title=Cosmogenesis: the growth of order in the universe |location=New York |publisher=Oxford University Press |date=1990 |editor-first=David |editor-last=Layzer}}</ref> is any model concerning the origin of the [[cosmos]] or the [[universe]].<ref name="DicAstro2">{{Cite encyclopedia |year=2012 |title=A Dictionary of Astronomy |publisher=[[Oxford University Press]] |last=Ridpath |first=Ian}}</ref><ref name="CosmoToday2">{{Cite journal |last=Woolfson |first=Michael Mark |author-link=Michael Woolfson |year=1979 |title=Cosmogony Today |journal=Quarterly Journal of the Royal Astronomical Society |volume=20 |issue=2 |pages=97–114 |bibcode=1979QJRAS..20...97W}}</ref> | |||
[[ | == Types == | ||
While cosmogony generally refers to origin stories, the nature and subject of these stories varies with times and sources. [[Ancient Greece]] developed a [[Early Greek cosmology#cosmogony|cosmogony]] focused on the origin of matter, space, and time with a transition from [[Chaos (cosmogony)|Chaos]] to [[Cosmos]]. This was a form of "philosophical cosmogony" that is distinct from modern [[empirical]] science but which nevertheless dealt with many similar questions.<ref>{{Cite book |last=Gregory |first=Andrew |title=Ancient Greek cosmogony |date=2007 |publisher=Duckworth |isbn=978-0-7156-3477-6 |location=London}}</ref>{{rp|7}} Another type of cosmogony focuses on the [[formation and evolution of the Solar System]].<ref name="CosmoToday2" /> or sometimes the [[galaxy formation|formation of galaxies]].<ref name="DicAstro2" /> The standard [[physical cosmology|cosmological]] [[scientific theory|model]] of the early development of the [[universe]] is the [[Big Bang]] theory,<ref name="Wollack">{{Cite web |last=Wollack |first=Edward J. |date=10 December 2010 |title=Cosmology: The Study of the Universe |url=http://map.gsfc.nasa.gov/universe/ |url-status=dead |archive-url=https://web.archive.org/web/20110514230003/http://map.gsfc.nasa.gov/universe/ |archive-date=14 May 2011 |access-date=27 April 2011 |website=Universe 101: Big Bang Theory |publisher=[[NASA]]}}</ref> but it is based on a model known to fail at the very earliest times.<ref name="Peacock-1998">{{Cite book |last=Peacock |first=J. A. |url=https://www.cambridge.org/core/product/identifier/9780511804533/type/book |title=Cosmological Physics |date=1998-12-28 |publisher=Cambridge University Press |isbn=978-0-521-41072-4 |edition=1 |doi=10.1017/cbo9780511804533}}</ref>{{rp|275}} Thus modern cosmogony is not generally a consequence of modern cosmology theories. | |||
== Scientific cosmogenesis == | |||
A [[Big Bang]] model for the dynamics of the universe is widely agreed among cosmologists. Like most physical models, Big Bang models describe changes of state. Few physical models are designed to determine [[initial condition]]s: initial states are given by experimental measurements or by hypothesis. | |||
In cosmology, the initial state would be the origin of the universe. It is considered a valid challenge to address but there are significant disagreements over even the form of acceptable answers.<ref name=Smeenk-2017>{{Citation |last=Smeenk |first=Christopher |title=Philosophy of Cosmology |date=2017 |work=The Stanford Encyclopedia of Philosophy |editor-last=Zalta |editor-first=Edward N. |url=https://plato.stanford.edu/archives/win2017/entries/cosmology/ |access-date=2025-09-16 |edition=Winter 2017 |publisher=Metaphysics Research Lab, Stanford University |last2=Ellis |first2=George}}</ref> | |||
== | === Initial singularity === | ||
{{main|Initial singularity}} | |||
Since the Big Bang model describes an expanding and cooling universe, it must have been denser and hotter in the past. Conceptually the model can be extrapolated back to time zero. However, this process cannot be run all the way back to time zero: the standard model assumes a density low enough to avoid quantum effects. At some point before time zero, the density exceeds the validity of general relativity.<ref name=Smeenk-2017/> This point in time is called the [[Planck time]].{{citation needed|date=September 2025}} | |||
=== | === General relativity initial state === | ||
One approach to the limitations of running Big Bang model back to time zero simply stops extrapolating when the limit of valid general relativity is reached. This model by itself fails in several ways. First, the observable universe is much more [[homogeneous]] than an extrapolated Big Bang can account for. This problem is called the [[horizon problem]] because events on opposite sides of the horizon could not have mixed in the early universe and thus should not be homogeneous now. Second, the expansion of the universe reduces curvature or equivalently increases flatness. Since the universe now is observed to be close to flat, a universe extrapolated back in time would have to be extremely flat. This almost but not quite zero curvature seems unnatural, an issue called the [[flatness problem]]. Third, this extrapolation gives poor results when compared to measurements of large scale structure and of the cosmic microwave background (CMB).<ref name=Smeenk-2017/> | |||
=== Initial state theories === | |||
Several different theories have been proposed as alternative to simple extrapolation of general relativity. The most successful approach is called [[cosmic inflation|inflation]]. In this model the universe goes through a very short phase of intense expansion not predicted by general relativity. The expansion is so immense and fast that all pre-existing particles are diluted and replaced by particles emerging from the field that drove inflation in an process called [[Cosmic inflation#Reheating|reheating]]. An initially homogeneous universe, inflated by an enormous factor explains why we can see homogeneous features across distances which ordinary causality asserts are independent.<ref name=Smeenk-2017/> | |||
When combined with the Big Bang and other concepts of cosmology, inflation becomes the | |||
consensus or [[Lambda CDM|standard model of cosmology]], a model which successfully predicts details of large scale structure and the CMB.{{citation needed|date=September 2025}} While inflation has been successful in developing an initial state for Big Bang models, it does not by itself describe the origin of the universe. The rapid expansion erases evidence of physical processes occurring before inflation.<ref name=Smeenk-2017/> | |||
=== Quantum cosmology=== | |||
[[Sean M. Carroll]], who specializes in [[Physical cosmology|theoretical cosmology]] and [[Field (physics)|field theory]], explains two competing explanations for the origins of the [[Gravitational singularity|singularity]], which is the center of a space in which a characteristic is limitless<ref name=":0">{{Cite web |last=Carroll |first=Sean |date=28 April 2012 |title=A Universe from Nothing? |url=http://blogs.discovermagazine.com/cosmicvariance/2012/04/28/a-universe-from-nothing/#.XMQHyM9KhmA |access-date=22 April 2019 |website=Science for the Curious |archive-date=10 May 2016 |archive-url=https://web.archive.org/web/20160510012738/http://blogs.discovermagazine.com/cosmicvariance/2012/04/28/a-universe-from-nothing/#.XMQHyM9KhmA |url-status=dead }}</ref> (one example is the singularity of a [[black hole]], where [[gravity]] is the characteristic that becomes {{nowrap|limitless{{hsp}}{{mdash}}{{hsp}}}}infinite). | [[Sean M. Carroll]], who specializes in [[Physical cosmology|theoretical cosmology]] and [[Field (physics)|field theory]], explains two competing explanations for the origins of the [[Gravitational singularity|singularity]], which is the center of a space in which a characteristic is limitless<ref name=":0">{{Cite web |last=Carroll |first=Sean |date=28 April 2012 |title=A Universe from Nothing? |url=http://blogs.discovermagazine.com/cosmicvariance/2012/04/28/a-universe-from-nothing/#.XMQHyM9KhmA |access-date=22 April 2019 |website=Science for the Curious |archive-date=10 May 2016 |archive-url=https://web.archive.org/web/20160510012738/http://blogs.discovermagazine.com/cosmicvariance/2012/04/28/a-universe-from-nothing/#.XMQHyM9KhmA |url-status=dead }}</ref> (one example is the singularity of a [[black hole]], where [[gravity]] is the characteristic that becomes {{nowrap|limitless{{hsp}}{{mdash}}{{hsp}}}}infinite). | ||
When the universe started to expand, the Big Bang occurred, which evidently began the universe.{{citation_needed|date=May 2025}} The other explanation, the [[Hartle–Hawking state]], held by proponents such as [[Stephen Hawking]], asserts that time did not exist when it emerged along with the universe. This assertion implies that the universe does not have a beginning, as time did not exist "prior" to the universe. Hence, it is unclear whether properties such as space or time emerged with the singularity and the known universe.<ref name=":0" /><ref name=":1">{{Cite book |last1=Carroll |first1=Sean |title=Spacetime and Geometry: An Introduction to General Relativity |last2=Carroll |first2=Sean M. |publisher=Pearson |year=2003}}</ref>{{clarify|date=March 2021 |reason=This paragraph is a hopeless muddle after the second sentence.}} | |||
== Mythology == | |||
{{Main|Creation myth}} | {{Main|Creation myth}} | ||
[[File:Sumerian creation myth.jpg|thumb|The [[Library of Ashurbanipal|Sumerian tablet]] containing parts of the [[Eridu Genesis]]]] | [[File:Sumerian creation myth.jpg|thumb|The [[Library of Ashurbanipal|Sumerian tablet]] containing parts of the [[Eridu Genesis]]]] | ||
[[File:The Untangling of Chaos, or the Creation of the Four Elements LACMA 54.70.1a.jpg|thumb|The Creation of the Four Elements as published by Holland in 1589 from [[Ovid]]'s book: ''Metamorphoses'']] | |||
In mythology, [[Creation myth|creation]] or cosmogonic myths are narratives describing the beginning of the [[universe]] or [[cosmos]]. | In mythology, [[Creation myth|creation]] or cosmogonic myths are narratives describing the beginning of the [[universe]] or [[cosmos]]. | ||
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[[Category:Cosmogony| ]] | [[Category:Cosmogony| ]] | ||
[[Category:Creation myths]] | [[Category:Creation myths]] | ||
[[Category:Natural philosophy]] | [[Category:Natural philosophy]] | ||
[[Category:Origins]] | [[Category:Origins]] | ||
[[Category:Physical cosmology]] | [[Category:Physical cosmology]] | ||
[[Category:Concepts in astronomy]] | [[Category:Concepts in astronomy]] | ||
Latest revision as of 15:23, 15 November 2025
Template:Short description Template:Hatnote group Template:Use dmy dates
Cosmogony, also spelled as cosmogeny,[1] or cosmogenesis[2] is any model concerning the origin of the cosmos or the universe.[3][4]
Types
While cosmogony generally refers to origin stories, the nature and subject of these stories varies with times and sources. Ancient Greece developed a cosmogony focused on the origin of matter, space, and time with a transition from Chaos to Cosmos. This was a form of "philosophical cosmogony" that is distinct from modern empirical science but which nevertheless dealt with many similar questions.[5]Template:Rp Another type of cosmogony focuses on the formation and evolution of the Solar System.[4] or sometimes the formation of galaxies.[3] The standard cosmological model of the early development of the universe is the Big Bang theory,[6] but it is based on a model known to fail at the very earliest times.[7]Template:Rp Thus modern cosmogony is not generally a consequence of modern cosmology theories.
Scientific cosmogenesis
A Big Bang model for the dynamics of the universe is widely agreed among cosmologists. Like most physical models, Big Bang models describe changes of state. Few physical models are designed to determine initial conditions: initial states are given by experimental measurements or by hypothesis. In cosmology, the initial state would be the origin of the universe. It is considered a valid challenge to address but there are significant disagreements over even the form of acceptable answers.[8]
Initial singularity
Script error: No such module "Labelled list hatnote". Since the Big Bang model describes an expanding and cooling universe, it must have been denser and hotter in the past. Conceptually the model can be extrapolated back to time zero. However, this process cannot be run all the way back to time zero: the standard model assumes a density low enough to avoid quantum effects. At some point before time zero, the density exceeds the validity of general relativity.[8] This point in time is called the Planck time.Script error: No such module "Unsubst".
General relativity initial state
One approach to the limitations of running Big Bang model back to time zero simply stops extrapolating when the limit of valid general relativity is reached. This model by itself fails in several ways. First, the observable universe is much more homogeneous than an extrapolated Big Bang can account for. This problem is called the horizon problem because events on opposite sides of the horizon could not have mixed in the early universe and thus should not be homogeneous now. Second, the expansion of the universe reduces curvature or equivalently increases flatness. Since the universe now is observed to be close to flat, a universe extrapolated back in time would have to be extremely flat. This almost but not quite zero curvature seems unnatural, an issue called the flatness problem. Third, this extrapolation gives poor results when compared to measurements of large scale structure and of the cosmic microwave background (CMB).[8]
Initial state theories
Several different theories have been proposed as alternative to simple extrapolation of general relativity. The most successful approach is called inflation. In this model the universe goes through a very short phase of intense expansion not predicted by general relativity. The expansion is so immense and fast that all pre-existing particles are diluted and replaced by particles emerging from the field that drove inflation in an process called reheating. An initially homogeneous universe, inflated by an enormous factor explains why we can see homogeneous features across distances which ordinary causality asserts are independent.[8] When combined with the Big Bang and other concepts of cosmology, inflation becomes the consensus or standard model of cosmology, a model which successfully predicts details of large scale structure and the CMB.Script error: No such module "Unsubst". While inflation has been successful in developing an initial state for Big Bang models, it does not by itself describe the origin of the universe. The rapid expansion erases evidence of physical processes occurring before inflation.[8]
Quantum cosmology
Sean M. Carroll, who specializes in theoretical cosmology and field theory, explains two competing explanations for the origins of the singularity, which is the center of a space in which a characteristic is limitless[9] (one example is the singularity of a black hole, where gravity is the characteristic that becomes limitlessTemplate:HspTemplate:MdashTemplate:Hspinfinite).
When the universe started to expand, the Big Bang occurred, which evidently began the universe.Script error: No such module "Unsubst". The other explanation, the Hartle–Hawking state, held by proponents such as Stephen Hawking, asserts that time did not exist when it emerged along with the universe. This assertion implies that the universe does not have a beginning, as time did not exist "prior" to the universe. Hence, it is unclear whether properties such as space or time emerged with the singularity and the known universe.[9][10]Template:Clarify
Mythology
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In mythology, creation or cosmogonic myths are narratives describing the beginning of the universe or cosmos.
Some methods of the creation of the universe in mythology include:
- the will or action of a supreme being or beings,
- the process of metamorphosis,
- the copulation of female and male deities,
- from chaos,
- or via a cosmic egg.[11]
Creation myths may be etiological, attempting to provide explanations for the origin of the universe. For instance, Eridu Genesis, the oldest known creation myth, contains an account of the creation of the world in which the universe was created out of a primeval sea (Abzu).[12][13] Creation myths vary, but they may share similar deities or symbols. For instance, the ruler of the gods in Greek mythology, Zeus, is similar to the ruler of the gods in Roman mythology, Jupiter.[14] Another example is the ruler of the gods in Tagalog mythology, Bathala, who is similar to various rulers of certain pantheons within Philippine mythology such as the Bisaya's Kaptan.[15][16]
Compared with cosmology
In the humanities, the distinction between cosmogony and cosmology is blurred. For example, in theology, the cosmological argument for the existence of God (pre-cosmic cosmogonic bearer of personhood) is an appeal to ideas concerning the origin of the universe and is thus cosmogonical.[17] Some religious cosmogonies have an impersonal first cause (for example Taoism).[18]
However, in astronomy, cosmogony can be distinguished from cosmology, which studies the universe and its existence, but does not necessarily inquire into its origins. There is therefore a scientific distinction between cosmological and cosmogonical ideas. Physical cosmology is the science that attempts to explain all observations relevant to the development and characteristics of the universe on its largest scale. Some questions regarding the behaviour of the universe have been described by some physicists and cosmologists as being extra-scientific or metaphysical. Attempted solutions to such questions may include the extrapolation of scientific theories to untested regimes (such as the Planck epoch), or the inclusion of philosophical or religious ideas.[10][17][6]
See also
- Template:Annotated link
- Template:Annotated link
- Template:Annotated link
- Template:Annotated link
- Why is there anything at all?
References
External links
Template:Portal bar Template:Authority control
- ↑ Script error: No such module "Citation/CS1".
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- ↑ Garverza, J. K. (2014). The Myths of the Philippines. University of the Philippines.
- ↑ Jocano, F. L. (1969). Philippine Mythology. Quezon City: Capitol Publishing House Inc.
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "citation/CS1".