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:''For other uses, see [[Space (disambiguation)]]. See [[outer space]] for space as in astronomy and spaceships etc.'' |
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space is fake |
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'''Space''' has been an interest for [[philosophy|philosophers]] and [[science|scientists]] for much of [[human]] history. The term is used somewhat differently in different fields of study, hence it is difficult to provide an uncontroversial and clear definition outside of specific defined contexts. Disagreement also exists on whether space itself can be measured or is part of the measuring system. (See [[#Space in philosophy|Space in philosophy]].) Many fields use an [[operational definition]] in which the units of [[measurement]] are defined, but not space itself. |
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==In philosophy== |
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{{main|Philosophy of space and time}} |
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Space has a range of definitions: |
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*One view of space is that it is part of the fundamental structure of the universe, a set of [[dimension]]s in which [[object (philosophy)|object]]s are separated and located, have size and shape, and through which they can move. |
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*A contrasting view is that space is part of a fundamental [[Abstract structure|abstract]] mathematical [[concept]]ual framework (together with [[time]] and [[number]]) within which we compare and [[quantity|quantify]] the distance between objects, their sizes, their shapes, and their speeds. In this view ''space'' does not refer to any kind of entity that is a "container" that objects "move through". |
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These opposing views are relevant also to definitions of time. Space is typically described as having three dimensions, and that three numbers are needed to specify the size of any object and/or its location with respect to another location. Modern [[physics]] does not treat space and time as independent dimensions, but treats both as features of [[space-time]] – a conception that challenges intuitive notions of distance and time. |
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An issue of [[philosophy|philosophical]] debate is whether space is an [[ontology|ontological]] entity itself, or simply a [[concept|conceptual]] framework we need to think (and talk) about the world. Another way to frame this is to ask, "Can space itself be measured, or is space part of the measurement system?" The same debate applies also to time, and an important formulation in both areas was given by [[Immanuel Kant]]. |
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In his ''[[Critique of Pure Reason]]'', Kant described space as an ''[[A priori and a posteriori (philosophy)|a priori]]'' intuition that (together with another ''a priori'' intuition, time) allows us to comprehend sense experience. With Kant, neither space nor time are conceived as [[substance]]s, but rather both are elements of a systematic [[framework]] we use to structure our experience. Spatial [[measurement]]s are used to quantify how far apart objects are, and temporal measurements are used to quantify how far apart [[Event (philosophy)|event]]s occur. |
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[[Schopenhauer]], in the preface to his ''On the Will in Nature'', stated that "space is the condition of the ''possibility'' of juxtaposition." This is in accordance with Kant's understanding of space as a form in the [[mind]] of an observing [[subject]]. |
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Similar philosophical questions concerning space include: Is space absolute or purely relational? Does space have one correct geometry, or is the geometry of space just a convention? Historical positions in these debates have been taken by [[Isaac Newton]] (space is absolute), [[Gottfried Leibniz]] (space is relational), and [[Henri Poincaré]] (spatial geometry is a convention). Two important thought-experiments connected with these questions are: Newton's [[bucket argument]] and Poincaré's [[sphere-world]]. |
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==In mathematics== |
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Space is a [[set]], with some particular properties and usually some additional [[mathematical structure|structure]]. It is not a formally defined concept as such, but a generic name for a number of similar concepts, most of which generalize some abstract properties of the physical concept of space. |
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In particular, a [[vector space]] and specifically a [[Euclidean space]] can be seen as generalizations of the concept of a Euclidean coordinate system. Important varieties of vector spaces with more imposed structure include [[Banach space]] and [[Hilbert space]]. Distance measurement is abstracted as the concept of [[metric space]] and volume measurement leads to the concept of [[measure space]]. |
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As far as the concept of [[Dimension#Mathematical dimensions|dimension]] is defined, although [[three-dimensional space]] is the most commonly thought of dimensional space, the number of dimensions for a space to exist need not be three: it can also be zero (a point), one (a line), two (a plane), more than three, finite or infinite, and with some definitions, a non-integer value. Mathematicians often study general structures that hold regardless of the number of dimensions |
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Kinds of mathematical spaces include: |
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*[[Banach space]] |
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*[[Calabi-Yau space]] |
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*[[Euclidean space]] |
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*[[Fréchet space]] |
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*[[Hausdorff space]] |
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*[[Hilbert space]] |
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*[[Kolmogorov space]] |
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*[[Metric space]] |
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*[[Minkowski space]] |
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*[[Probability space]] |
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*[[Projective space]] |
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*[[Proximity space]] |
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*[[Topological space]] |
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*[[Tychonoff space]] |
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*[[Uniform space]] |
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*[[Urysohn space]] |
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*[[Vector space]] |
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===In physics=== |
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Space is one of the few [[fundamental]] quantities in [[physics]], meaning that it cannot be defined via other quantities because there is nothing more fundamental known at present. Thus, similar to the definition of other fundamental quantities (like [[time]] and [[mass]]), space is defined via [[measurement]]. Currently, the standard space interval, called a standard meter or simply [[meter]], is defined as the [[speed of light|distance traveled by light in a vacuum]] during a time interval of 1/299792458 of a second (exact). This definition coupled with present definition of time makes our [[space-time]] to be [[Minkowski space]] and makes [[special relativity]] theory to be absolutely correct by [[definition]]. |
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In [[classical physics]], space is a three-dimensional [[Euclidean space]] where any position can be described using three [[coordinate system|coordinate]]s. Special and general relativity uses [[space-time]] rather than space; space-time is modeled as a four-dimensional space (with the time axis being [[imaginary]] in [[special relativity]] and [[real]] in [[general relativity]], and currently there are many theories which use more than four-dimensional spaces (both real and complex). |
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Before [[Einstein]]'s work on relativistic physics, time and space were viewed as independent dimensions. Einstein's discoveries have shown that due to relativity of motion our space and time can be mathematically combined into one symmetric object — space-time. (Distances in space or in time separately are not invariant versus Lorentz coordinate transformations, but distances in Minkowski space-time are — which justifies the name). |
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====In astronomy==== |
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{{main|Outer space}} |
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Space refers collectively to the relatively empty parts of the [[universe]]. Any area outside the [[celestial body's atmosphere|atmosphere]]s of any [[celestial body]] can be considered 'space'. Although space is certainly ''spacious'', it is not always empty, but can be filled with [[matter]] — say a tenuous [[Plasma (physics)|plasma]]. In particular, the boundary between space and [[Earth's atmosphere]] is conventionally set at the [[Karman line]]. |
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===Spatial measurement=== |
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{{main|Measurement}} |
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The measurement of ''physical space'' has long been important. [[Geometry]], the name given to the branch of [[mathematics]] which measures spatial relations, was popularised by the [[ancient Greeks]], although earlier societies had developed measuring systems. The [[SI|International System of Units]], (SI), is now the most common system of units used in the measuring of space, and is almost universally used within [[science]]. |
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[[Geography]] is the branch of science concerned with identifying and describing the [[Earth]], utilising spatial awareness to try and understand why things exist in specific locations. [[Cartography]] is the mapping of spaces to allow better navigation, for visualisation purposes and to act as a locational device. [[Geostatistics]] apply statistical concepts to collected spatial data in order to create an estimate for unobserved phenomena. [[Astronomy]] is the science involved with the observation, explanation and measuring of objects in [[outer space]]. |
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====In geography==== |
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Geographical space is called [[land]], and has a relation to [[ownership]] (in which space is seen as [[property]]). While some cultures assert the rights of the individual in terms of ownership, other cultures will identify with a communal approach to land ownership, while still other cultures such as [[Australian Aboriginals]], rather than asserting ownership rights to land, invert the relationship and consider that they are in fact owned by the land. [[Spatial planning]] is a method of regulating the use of space at land-level, with decisions made at regional, national and international levels. Space can also impact on human and cultural behaviour, being an important factor in [[architecture]], where it will impact on the design of buildings and structures, and on [[farming]]. |
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Ownership of space is not restricted to land. Ownership of [[airspace]] and of [[International waters|waters]] is decided internationally. Other forms of ownership have been recently asserted to other spaces — for example to the [[radio]] bands of the electromagnetic [[spectrum]] or to [[cyberspace]]. |
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[[Public space]] is a term used to define areas of land is collectively owned by the community, and managed in their name by delegated authorities. Such spaces are open to all, while [[private property]] is the land owned by an individual or company, for their own use and pleasure. |
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[[Abstract space]] is a term used in [[geography]] to refer to a hypothetical space characterized by complete homogeneity. When modeling activity or behavior, it is a conceptual tool used to limit [[extraneous variables]] such as terrain. |
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==In psychology== |
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The way in which space is perceived is an area which psychologists first began to study in the middle of the 19th century, and it is now thought by those concerned with such studies to be a distinct branch within [[psychology]]. Psychologists analysing the perception of space are concerned with how recognition of an object's physical appearance or its interactions are perceived. |
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Other, more specialised topics studied include [[amodal perception]] and [[object permanence]]. The [[perception]] of surroundings is important due to its necessary relevance to survival, especially with regards to [[hunting]] and [[self preservation]]. |
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[[Phobia]]s include: |
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*[[Agoraphobia]] is a fear of open spaces. |
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*[[Astrophobia]] is a fear of [[celestial]] space. |
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*[[Claustrophobia]] is a fear of enclosed spaces. |
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*[[Kenophobia]] is a fear of empty spaces. |
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==In physics== |
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In physics, [[time]] and [[mass]] are fundamental quantities and space is defined via time — as the distance d [[light]] travels in exactly 1/c second |
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<math>d = c \cdot t</math> |
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where c denotes the [[speed of light]]. Thus [[space-time]] is [[Minkowski space-time]] (See [[Lorentz coordinate transformation]]s). |
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==References== |
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* [http://search.eb.com/eb/article?tocId=46639 Space perception]. ''Encyclopædia Britannica'' from Encyclopædia Britannica Online. Accessed June 12, 2005. |
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==See also== |
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* [[Outer space]] |
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* [[Personal space]] |
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* [[Space exploration]] |
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{{Wikiquote}} |
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[[Category:Topology]] |
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[[Category:Environments]] |
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[[ca:Espai]] |
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[[da:Rum]] |
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[[de:Raum]] |
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[[el:Χώρο]] |
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[[eo:Spaco]] |
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[[es:Espacio]] |
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[[fa:فضا]] |
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[[fi:Avaruus]] |
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[[fr:Espace (notion)]] |
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[[gl:Espazo]] |
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[[he:מרחב]] |
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[[hu:Tér]] |
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[[ia:Spatio]] |
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[[io:Spaco]] |
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[[it:Spazio]] |
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[[ja:空間]] |
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[[ko:공간]] |
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[[mk:Простор]] |
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[[nl:Ruimte (geografie)]] |
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[[pl:Przestrzeń]] |
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[[pt:Espaço]] |
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[[ru:Пространство]] |
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[[simple:Space]] |
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[[sl:prostor]] |
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[[sq:Hapësira]] |
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[[sv:Rymden]] |
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[[tr:Uzay]] |
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[[zh:空间]] |
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Revision as of 21:10, 11 November 2006
- breaking news
space is fake