Cosmogony, or cosmogeny, is any scientific theory concerning the coming into existence or origin of the universe, or about how reality came to be. The word comes from the Greek κοσμογονία (or κοσμογενία), from κόσμος "cosmos, the world", and the root of γί(γ)νομαι / γέγονα "to be born, come about". In the specialised context of space science and astronomy, the term refers to theories of creation of (and study of) the Solar System.
The Big Bang theory is the prevailing cosmological model of the early development of the universe. The most commonly held view is the universe was once a gravitational singularity which then expanded rapidly from this hot and dense state. While this expansion is well-modeled by the Big Bang theory, the origins of the singularity remains one of the unsolved problems in physics. Scientists continue to try and create a naturalistic cosmogony using the scientific method, although there are several problems that will likely need to be resolved before significant progress can be made in this direction.
One problem is that there is currently no theoretical model that explains the earliest moments of the universe's existence (Planck time) because of a lack of a testable theory of quantum gravity. Researchers of string theory and its extensions (for example, M theory), and of loop quantum cosmology, have nevertheless proposed solutions. Another issue facing the field of particle physics is a need for more expensive and technologically advanced particle accelerators to test proposed theories (for example, that the universe was caused by colliding membranes).
Developing a complete theoretical model has implications in both the philosophy of science and epistemology. For example, it would clarify the meaningful ways in which people can ask the question "why do we exist?".
Cosmogony compared with cosmology
Cosmogony can be distinguished from cosmology which studies the universe at large and throughout its existence, and which technically does not inquire directly into the source of its origins. There is some ambiguity between the two terms; for example, the cosmological argument from theology regarding the existence of God is technically an appeal to cosmogonical rather than cosmological ideas. In practice, there is 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 as a whole. Questions regarding why the universe behaves in such a way have been described by physicists and cosmologists as being extra-scientific, though speculations are made from a variety of perspectives that include extrapolation of scientific theories to untested regimes and philosophical or religious ideas.
Epistemological limitations to cosmogony
The assumptions of naturalism that underlie the scientific method have led some scientists, especially observationalists, to question whether the ultimate reason or source for the universe to exist can be answered in a scientific fashion. In particular, the principle of sufficient reason seems to indicate that there should be such an explanation, but whether a satisfactory explanation can be obtained through scientific inquiry is debatable. A scientific examination of cosmogony using existing physical models would face many challenges. For example, equations used to develop models of the origin do not in themselves explain how the conditions of the universe that the equations model came to be in the first place.
Theistic explanations for origins implicate one or more supernatural immortal beings as the first cause, although these are often dismissed as God of the gaps type fallacies or arguments from ignorance. Such explanations tend to provide no explanation for the existence of the deity, which can be interpreted as simply replacing one existence question with another that a priori can not be answered. Nondual explanations by contrast state that the very question is misleading, since it contains erroneous assumptions of beginnings, endings and the nature of existence itself, and consider the visible universe as phenomenology.
As a result of this, scientific cosmogonies are sometimes supplemented by reference to metaphysical and theistic belief systems. The problem can be summarised as three classical paradoxes. These paradoxes (discussed by both Kierkegaard and Leibniz) are:
- reconciling a doctrine of causation (similar to the 13th century proof of God posed by Thomas Aquinas);
- reconciling the conservation law ("something from nothing");
- reconciling issues of temporal (as in Zeno's paradoxes) and logical regression.
However, some of the metaphysical principles used to formulate these classical paradoxes no longer enjoy an unchallenged status as laws of thought. For instance, quantum mechanics gives an independent motivation to challenge the principle of sufficient reason.
Scientists have only early ideas of the young universe (or its beginning, for those who postulate that it had one). As of 2011, no accelerator experiments probe energies of sufficient magnitude to provide any experimental insight into the behavior of matter at the energy levels that prevailed during this period. That is, further technological and conceptual advance is needed to test aspects of these theories. Proposed scenarios differ radically. Some examples include String theory and M theory, the Hartle–Hawking initial state, string landscape, brane inflation, and the ekpyrotic universe. Some of these are mutually compatible, while others are not. The Big Bounce is a theoretical scientific model of the formation of the known universe. It is implied by the cyclic model or oscillatory universe interpretation of the Big Bang where the first cosmological event was the result of the collapse of a previous universe.
Planck time limitations to cosmogony
Planck time (10−43 s) is the time it would take a photon traveling at the speed of light to cross a distance equal to the Planck length (1.616252×10−35 meters). It has been proposed that this may be the hypothetical "quantum of time", the smallest measurement of time that has any meaning.
Although the laws of physics lose experimental support at the Planck time, modern science has sought to clarify the nature of these paradoxes, so far with only limited success. For example, one can apply the current understanding of grand unified theories (GUTs) – both quasi-classical (such as general relativity) and modern (such as quantum gravity, superstring, and M-theories) – to these three primary cosmogonic paradoxes in thought experiments. While these result in some contradictions and lack completeness in a mathematical sense (being based on axioms that are 'merely' self-evident, but not robust under the stresses of radical scepticism) these paradoxes can nonetheless be analysed rationally using the subatomic applications of quantum cosmology, particularly through the employment of the Schrödinger wave equations.
In each case, where general relativity fails as the curvature of space-time invokes singularities from its equations at t = 0, the statistically "grey" nature of quantum cosmology tends to allow a scientific rationale to account for each paradox, and in so doing allows for a scientific perspective on previously theistic terrain. For example, application of quantum "fuzziness" (per the Wheeler–DeWitt application of subatomic position and momentum equations to universal radius and expansion) avoids boundary issues, as developed in the Hartle–Hawking wave function.
All such equations are based on differentials, which assume a continuum, where in our universe, affected by the Planck length and other minimum scales, this continuum has only limited meaning, about which philosophy remains in a state of semantic flux.
- Digital physics
- Esoteric cosmology
- Metaphysical cosmology
- Religious cosmology
- Ultimate fate of the universe
- ^ Wollack, Edward J. (10 December 2010). "Cosmology: The Study of the Universe". Universe 101: Big Bang Theory. NASA. http://map.gsfc.nasa.gov/universe/. Retrieved 27 April 2011.
- ^ http://genesismission.jpl.nasa.gov/educate/scimodule/Cosmogony/CosmogonyPDF/CosCosmolTT.pdf
- ^ "Penn State Researchers Look Beyond The Birth Of The Universe". Science Daily. May 17, 2006. http://www.sciencedaily.com/releases/2006/05/060515232747.htm. Referring to Ashtekar, Abhay; Pawlowski, Tomasz; Singh, Parmpreet (2006). "Quantum Nature of the Big Bang". Physical Review Letters 96 (14): 141301. arXiv:gr-qc/0602086. Bibcode 2006PhRvL..96n1301A. doi:10.1103/PhysRevLett.96.141301. PMID 16712061.
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