What, When, Where, How, Why?
Cosmogony
Introduction, Important Definitions and Related Concepts:
Cosmogony, or cosmogeny, is any 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 specialized context of space science and astronomy, the term refers to theories of creation of (and study of) the Solar System. 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 which include extrapolation of scientific theories to untested regimes and philosophical or religious ideas. Attempts to create a naturalistic cosmogony are subject to two separate limitations. One is based in the philosophy of science and the epistemological constraints of science itself, especially with regards to whether scientific inquiry can ask questions of "why" the universe exists. Another more pragmatic problem is that there is no physical model which can explain the earliest moments of the universe's existence (Planck time) because of a lack of a consistent theory of quantum gravity. The word theory has a lot of distinct meanings in different fields of knowledge, depending on their methodologies and the context of discussion. In science a theory is a testable model of the manner of interaction of a set of natural phenomena, capable of predicting future occurrences or observations of the same kind, and capable of being tested through experiment or otherwise verified through empirical observation. It follows from this that for scientists "theory" and "fact" do not necessarily stand in opposition. For example, it is a fact that an apple dropped on earth has been observed to fall towards the center of the planet, and the theories commonly used to describe and explain this behavior are Newton's theory of universal gravitation (see also gravitation), and the theory of general relativity. In common usage, the word theory is often used to signify a conjecture, an opinion, or a speculation. In this usage, a theory is not necessarily based on facts; in other words, it is not required to be consistent with true descriptions of reality. This usage of theory leads to the common incorrect statements. True descriptions of reality are more reflectively understood as statements which would be true independently of what people think about them. According to the National Academy of Sciences,
Some scientific explanations are so well established that no new evidence is likely to alter them. The explanation becomes a scientific theory. In everyday language a theory means a hunch or speculation. Not so in science. In science, the word theory refers to a comprehensive explanation of an important feature of nature that is supported by many facts gathered over time. Theories also allow scientists to make predictions about as yet unobserved phenomena.[1] Existence is what is asserted by the verb 'exist' (derived from the Latin word 'existere', meaning to appear or emerge or stand out). The word 'exist' is certainly a grammatical predicate, but philosophers have long disputed whether it is also a logical predicate. Some philosophers claim that it predicates something called 'existence' of the subject. Thus 'four-leaved clover exists' predicates 'exists' of the subject 'four-leafed clover'. Cognates for this predicate are 'is real', 'has being', 'is found in reality', 'is in the real world' and so on. Other philosophers have denied that existence is logically a predicate, and claim that it is merely what is asserted by the etymologically distinct verb 'is', and that all statements containing the predicate 'exists' can be reduced to statements that do not use this predicate. For example, 'Four-leaved clover exists' can be analysed into the equivalent statement 'some clover is four-leaved', where the verb 'is' connects the subject 'some clover' with the predicate 'four-leaved'. This philosophical question is an old one, and has been discussed and argued over by philosophers from Aristotle, through Avicenna, Aquinas, Scotus, Hume, Kant, Kierkegaard and many others. The Universe is most commonly defined as everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them. However, the term "universe" may be used in slightly different contextual senses, denoting such concepts as the cosmos, the world or Nature. Astronomical observations indicate that the universe is at least 13.73 ± 0.12 billion years old and at least 93 billion light years across. The event that started the universe is called the Big Bang. At this point in time all matter and energy of the observable universe was concentrated in one point of infinite density. After the Big Bang the universe started to expand to its present form. Since special relativity states that matter cannot exceed the speed of light in a fixed space-time, it may seem paradoxical that two galaxies can be separated by 93 billion light years in 13 billion years; however, this separation is a natural consequence of general relativity. Stated simply, space can expand with no intrinsic limit on its rate; thus, two galaxies can separate more quickly than the speed of light if the space between them grows. Experimental measurements such as the redshifts and spatial distribution of distant galaxies, the cosmic microwave background radiation, and the relative percentages of the lighter chemical elements, support this theoretical expansion and, more generally, the Big Bang theory, which proposes that space itself was created ex nihilo at a specific time in the past. Recent observations have shown that this expansion is accelerating, and that most of the matter and energy in the universe is fundamentally different from that observed on Earth and not directly observable (cf. dark energy). The imprecision of current observations has hindered predictions of the ultimate fate of the universe. Experiments suggest that the universe has been governed by the same physical laws and constants throughout its extent and history. The dominant force at cosmological distances is gravity, and general relativity is currently the most accurate theory of gravitation. The remaining three fundamental forces and the particles on which they act are described by the Standard Model. The universe has at least three dimensions of space and one of time, although extremely small additional dimensions cannot be ruled out experimentally. Spacetime appears to be smoothly and simply connected, and space has very small mean curvature, so that Euclidean geometry is accurate on the average throughout the universe. According to some speculations, this universe may be one of many disconnected universes, which are collectively denoted as the multiverse. In one theory, there is an infinite variety of universes, each with different physical constants. In another theory, new universes are spawned with every quantum measurement. By definition, these speculations cannot currently be tested experimentally. Throughout recorded history, several cosmologies and cosmogonies have been proposed to account for observations of the universe. The earliest quantitative models were developed by the ancient Greeks, who proposed that the universe possesses infinite space and has existed eternally, but contains a single set of concentric spheres of finite size - corresponding to the fixed stars, the Sun and various planets - rotating about a spherical but unmoving Earth. Over the centuries, more precise observations and improved theories of gravity led to Copernicus' heliocentric model and the Newtonian model of the solar system, respectively. Further improvements in astronomy led to the characterization of the Milky Way, and the discovery of other galaxies and the microwave background radiation; careful studies of the distribution of these galaxies and their spectral lines have led to much of modern cosmology. Reality, in everyday usage, means "the state of things as they actually exist". [1] [2] The term reality, in its widest sense, includes everything that is, whether or not it is observable or comprehensible. Reality in this sense may include both being and nothingness, whereas existence is often restricted to being (compare with nature). In other words, "reality", as a philosophical category includes the formal concept of "nothingness" and articulations and combinations of it with other concepts (those possessing extension in physical objects or processes for example). In the strict sense of western philosophy, there are levels or gradation to the nature and conception of reality. These levels include, from the most subjective to the most rigorous: phenomenological reality, truth, fact, and axiom. Space is the property of the universe[1] in which matter is physically extended and objects have positions relative to one another[2]. In classical mechanics, space was originally treated as being separate from time and is thought of as one of the few fundamental physical quantities. In Isaac Newton's view space was absolute, and held that it exists permanently and independently of whether there is any matter in the space or moving through it[3].
In mathematics spaces with different geometries and numbers of dimensions are described, and this is used in modern physics where both space and time are to be thought of as part of the boundless four-dimensional continuum known as spacetime. From the experimental support for Albert Einstein's theory of relativity scientists now find that space and time cannot be entirely separated. In addition, space is found to have physical properties[4] including intrinsic curvature which varies according to mass distribution. Therefore it was Einstein's view that space and matter cannot be entirely separated either. Among physicists and philosophers there is disagreement regarding whether space is itself an entity, or is part of a conceptual framework.[5] Science (from the Latin scientia, meaning "knowledge") is the effort to understand, or to understand better, how the physical world works, with observable evidence as the basis of that understanding. It is done through observation of phenomena, and/or through experimentation that tries to simulate events under controlled conditions. Astronomy (from the Greek words astro(αστέρι) = star and nomos(νόμος) = law) is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation). It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe. Astronomy is one of the oldest sciences. Astronomers of early civilizations performed methodical observations of the night sky, and astronomical artifacts have been found from much earlier periods. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and even astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics. Since the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring and analyzing data, mainly using basic principles of physics. Theoretical astronomy is oriented towards the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the observational results, and observations being used to confirm theoretical results. Amateur astronomers have contributed to many important astronomical discoveries, and astronomy is one of the few sciences where amateurs can still play an active role, especially in the discovery and observation of transient phenomena. Old or even ancient astronomy is not to be confused with astrology, the belief system that claims that human affairs are correlated with the positions of celestial objects. Although the two fields share a common origin and a part of their methods (namely, the use of ephemerides), they are distinct.[1] The Solar System (or Solar system, solar system[a]) consists of the Sun and those celestial objects bound to it by gravity. These objects are the eight planets and their 166 known moons;[1] three dwarf planets (Ceres, Pluto, and Eris) and their four known moons; and billions of small bodies, including asteroids, Kuiper belt objects, comets, meteoroids, and interplanetary dust. In broad terms, the charted regions of the Solar System consist of the Sun, four terrestrial inner planets, an asteroid belt composed of small rocky bodies, four gas giant outer planets, and a second belt, the Kuiper belt, composed of icy objects. Beyond the Kuiper belt is the scattered disc, the heliopause, and ultimately the hypothetical Oort cloud. In order of their distances from the Sun, the terrestrial planets are:
The outer gas giants (or Jovians) are:
The three dwarf planets are
- Ceres, the largest object in the asteroid belt; Pluto, the largest known object in the Kuiper belt; Eris, the largest known object in the scattered disc.
Six of the eight planets and two of the dwarf planets are in turn orbited by natural satellites, usually termed "moons" after Earth's Moon, and each of the outer planets is encircled by planetary rings of dust and other particles. All the planets except Earth are named after deities from Greco-Roman mythology. Cosmology, from the Greek: κοσμολογία (cosmologia, κόσμος (cosmos) order + λογος (logos) word, reason, plan) is the quantitative (usually mathematical) study of the Universe in its totality, and by extension, humanity's place in it. Though the word cosmology is recent (first used in 1730 in Christian Wolff's Cosmologia Generalis), study of the Universe has a long history involving science, philosophy, esotericism, and religion. The cosmological argument is a metaphysical argument for the existence of God, or a first mover of the cosmos. It is traditionally known as an "argument from universal causation", an "argument from first cause", "The Causal Argument" and also as an "uncaused cause" or "unmoved mover" argument. Whichever term is used, there are three basic variants of this argument, each with subtle but important distinctions: the argument from causation in esse, the argument from causation in fieri, and the argument from contingency. The cosmological argument does not attempt to prove anything about the first cause or about God, except to argue that such a cause must exist. This cause is known in Latin as "causa sui". Theology is the study of religion from a religious perspective. It has been defined as reasoned discourse about God or the gods, or more generally about religion or spirituality. It can be contrasted with religious studies, which is the study of religion from a secular perspective. Theologians use various forms of analysis and argument (philosophical, ethnographic, historical) to help understand, explain, test, critique, defend or promote any of a myriad of religious topics.