What Is Universe???

The universe is 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.

Thursday, February 5, 2009

Cosmology

Cosmology (from Greek κοσμολογία - κόσμος, kosmos, "universe"; and -λογία, -logia, "study") is 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.



Disciplines

In recent times, physics and astrophysics have come to play a central role in shaping the understanding of the universe through scientific observation and experiment; or what is known as physical cosmology shaped through both mathematics and observation in the analysis of the whole universe. In other words, in this discipline, which focuses on the universe as it exists on the largest scale and at the earliest moments, is generally understood to begin with the big bang (possibly combined with cosmic inflation) - an expansion of space from which the Universe itself is thought to have emerged ~13.7±0.2×109 (13.7 billion) years ago . From its violent beginnings and until its various speculative ends, cosmologists propose that the history of the Universe has been governed entirely by physical laws. Theories of an impersonal universe governed by physical laws were first proposed by Roger Bacon, a somewhat persecuted member of the Catholic Church. Between the domains of religion and science, stands the philosophical perspective of metaphysical cosmology. This ancient field of study seeks to draw intuitive conclusions about the nature of the universe, man, god and/or their relationships based on the extension of some set of presumed facts borrowed from spiritual experience and/or observation.

But metaphysical cosmology has also been observed as the placing of man in the universe in relationship to all other entities. This is demonstrated by the observation made by Marcus Aurelius of a man's place in that relationship: " He who does not know what the world is does not know where he is, and he who does not know for what purpose the world exists, does not know who he is, nor what the world is.” This is the purpose of the ancient metaphysical cosmology. However, Stoicism rejected Aristotle's theory of universals as being "in the things themselves," calling them "figments of the mind." Stanford Encyclopedia of Philosophy adopting the concept of universals as being "concepts," and therefore of the mind, and therefore controllable by free will. Thus, we get the analysis of Aurelius' that the nature of the universe is not from "intuition," but from a free-will, conceptual understanding of the nature of the universe.

Cosmology is often an important aspect of the creation myths of religions that seek to explain the existence and nature of reality. In some cases, views about the creation (cosmogony) and destruction (eschatology) of the universe play a central role in shaping a framework of religious cosmology for understanding humanity's role in the universe.

A more contemporary distinction between religion and philosophy, esoteric cosmology is distinguished from religion in its less tradition-bound construction and reliance on modern "intellectual understanding" rather than faith, and from philosophy in its emphasis on spirituality as a formative concept.

There are many historical cosmologies:

“…the universe itself acts on us as a random, inefficient, and yet in the long run effective, teaching machine. …our way of looking at the universe has gradually evolved through a natural selection of ideas.” —Steven Weinberg


Physical cosmology

Physical cosmology is the branch of physics and astrophysics that deals with the study of the physical origins and evolution of the Universe. It also includes the study of the nature of the Universe on its very largest scales. In its earliest form it was what is now known as celestial mechanics, the study of the heavens. The Greek philosophers Aristarchus of Samos, Aristotle and Ptolemy proposed different cosmological theories. In particular, the geocentric Ptolemaic system was the accepted theory to explain the motion of the heavens until Nicolaus Copernicus, and subsequently Johannes Kepler and Galileo Galilei proposed a heliocentric system in the 16th century. This is known as one of the most famous examples of epistemological rupture in physical cosmology.

Wit Isaac Newton and the 1687 publication of Principia Mathematica, the problem of the motion of the heavens was finally solved. Newton provided a physical mechanism for Kepler's laws and his law of universal gravitation allowed the anomalies in previous systems, caused by gravitational interaction between the planets, to be resolved. A fundamental difference between Newton's cosmology and those preceding it was the Copernican principle that the bodies on earth obey the same physical laws as all the celestial bodies. This was a crucial philosophical advance in physical cosmology.

Modern scientific cosmology is usually considered to have begun in 1917 with Albert Einstein's publication of his final modification of general relativity in the paper "Cosmological Considerations of the General Theory of Relativity," (although this paper was not widely available outside of Germany until the end of World War I). General relativity prompted cosmogonists such as Willem de Sitter, Karl Schwarzschild and Arthur Eddington to explore the astronomical consequences of the theory, which enhanced the growing ability of astronomers to study very distant objects. Prior to this (and for some time afterwards), physicists assumed that the Universe was static and unchanging. In parallel to this dynamic approach to cosmology, a debate was unfolding regarding the nature of the cosmos itself. On the one hand, Mount Wilson astronomer Harlow Shapley championed the model of a cosmos made up of the Milky Way star system only. Heber D. Curtis, on the other hand, suggested spiral nebulae were star systems in their own right, island universes. This difference of ideas came to a climax with the organization of the Great Debate at the meeting of the (US) National Academy of Sciences in Washington on 26 April 1920. The resolution of the debate on the structure of the cosmos came with the detection of novae in the Andromeda galaxy by Edwin Hubble in 1923 and 1924. Their distance established spiral nebulae well beyond the edge of the Milky Way and as galaxies of their own. Subsequent modeling of the universe explored the possibility that the cosmological constant introduced by Einstein in his 1917 paper may result in an expanding universe, depending on its value. Thus the big bang theory was proposed by the Belgian priest Georges Lemaître in 1927 which was subsequently corroborated by Edwin Hubble's discovery of the red shift in 1929 and later by the discovery of the cosmic microwave background radiation by Arno Penzias and Robert Woodrow Wilson in 1964. These findings were a first step to rule out some of many alternative physical cosmologies.


Recent observations made by the COBE and WMAP satellites observing this background radiation have effectively, in many scientists' eyes, transformed cosmology from a highly speculative science into a predictive science, as these observations matched predictions made by a theory called Cosmic inflation, which is a modification of the standard big bang theory. This has led many to refer to modern times as the "Golden age of cosmology".


Metaphysical cosmology

Hand-coloured version of the anonymous wood engraving known as the Flammarion woodcut(1888).

In philosophy and metaphysics, cosmology deals with the world as the totality of space, time and all phenomena. Historically, it has had quite a broad scope, and in many cases was founded in religion. The ancient Greeks did not draw a distinction between this use and their model for the cosmos. However, in modern use it addresses questions about the Universe which are beyond the scope of science. It is distinguished from religious cosmology in that it approaches these questions using philosophical methods (e.g. dialectics). Modern metaphysical cosmology tries to address questions such as:

  • What is the origin of the Universe? What is its first cause? Is its existence necessary? (see monism, pantheism, emanationism and creationism)
  • What are the ultimate material components of the Universe? (see mechanism, dynamism, hylomorphism, atomism)
  • What is the ultimate reason for the existence of the Universe? Does the cosmos have a purpose?

Religious cosmology

Large scale structure of the Universe according to one Hindu cosmology.

Many world religions have creation myths that explain the beginnings of the Universe and life. Often these are derived from scriptural teachings and held to be part of the faith's dogma, but in some cases these are also extended through the use of philosophical and metaphysical arguments.

In some creation myths, the universe was created by a direct act of a god or gods who are also responsible for the creation of humanity (see creationism). In many cases, religious cosmologies also foretell the end of the Universe, either through another divine act or as part of the original design.

  • Both Christianity and Judaism rely on the Genesis narrative as a scriptural account of cosmology. See also Biblical cosmology and Tzimtzum.
  • Islam relies on understanding from the Qur'an as its major source for explaining cosmology. See Islamic cosmology.
  • Certain adherents of Buddhism, Hinduism (See also Hindu cosmology) and Jainism believe that the Universe passes through endless cycles of creation and destruction, each cycle lasting for trillions of years (e.g. 331 trillion years, or the life-span of Brahma, according to Hinduism), and each cycle with sub-cycles of local creation and destruction (e.g. 4.32 billion years, or a day of Brahma, according to Hinduism). The Vedic (Hindu) view of the world sees one true divine principle self-projecting as the divine word, 'birthing' the cosmos that we know from the monistic Hiranyagarbha or Golden Womb.
  • A complex mixture of native Vedic gods, spirits, and demons, overlaid with imported Hindu and Buddhist deities, beliefs, and practices are the key to the Sri Lankan cosmology.
  • The Australian Aboriginal concept of Dreaming explains the creation of the universe as an eternal continuum; everywhen. Through certain ceremonies, the past "opens up" and comes into the present. Each topographical feature is a manifestation of dormant creation spirits; each individual has personal Dreamings and ceremonial responsibilities to look after the spirits/land, determined at birth, within this belief framework.

Many religions accept the findings of physical cosmology, in particular the Big Bang, and some, such as the Roman Catholic Church, have embraced it as suggesting a philosophical first cause. Others have tried to use the methodology of science to advocate for their own religious cosmology, as in intelligent design or creationist cosmologies.


Esoteric cosmology

Many esoteric and occult teachings involve highly elaborate cosmologies. These constitute a "map" of the Universe and of states of existences and consciousness according to the worldview of that particular doctrine. Such cosmologies cover many of the same concerns also addressed by religious and philosophical cosmology, such as the origin, purpose, and destiny of the Universe and of consciousness and the nature of existence. For this reason it is difficult to distinguish where religion or philosophy end and esotericism and/or occultism begins.

Common themes addressed in esoteric cosmology are emanation, involution, evolution, epigenesis, planes of existence, hierarchies of spiritual beings, cosmic cycles (e.g., cosmic year, Yuga), yogic or spiritual disciplines, and references to altered states of consciousness. Examples of esoteric cosmologies can be found in modern Theosophy, Gnosticism, Tantra (especially Kashmir Shaivism), Kabbalah, or Sufism.

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