HOME WEB NEWS IMAGES CLASSIFIEDS YELLOW PAGESPOLLS - SURVEYS WIKI COUNTRIES PHOTOS US UK INDIA
Cities Stocks Weather Movies Coupons Travel Blogs Health Horoscope Maps ASIA EUROPE Classifieds Yellow Pages
|
 1
|
This article is about the idea of space. For the space beyond Earth\'s atmosphere (as in astronomy and spaceships), see outer space. For all other uses, see space (disambiguation).
The concept of space has been of interest for philosophers and 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.) Science considers space to be a fundamental quantity (a quantity which can not be defined via other quantities because other quantities — like force and energy — are already defined via space). Thus an operational definition is used in which the procedure of measurement of space intervals (distances) and the units of measurement are defined.
Contents |
Space has a range of definitions:
These opposing views are relevant also to definitions of time. Space is typically described as having three dimensions, see Three-dimensional space 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.
An issue of philosophical debate is whether space is an ontological entity itself, or simply a conceptual framework humans 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.
In his Critique of Pure Reason, Kant described space as an a priori intuition that (together with another a priori intuition, time) allows us to comprehend sensual experience. Kant referred to such intuitions as noumena and as things in themselves. In Kant\'s view, neither space nor time are conceived of as substances, but rather both are elements of a systematic framework we use to structure our experience. Spatial measurements are used to quantify how far apart objects are, and temporal measurements are used to quantify how far apart events occur. However, these measurements are applied by our minds to categorize what we sense and are not an inherent part of the thing in itself.
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.
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.
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 distance traveled by light in a vacuum during a time interval of exactly 1/299,792,458 of a second. This definition coupled with present definition of the second is based on the special theory of relativity, that our space-time is a Minkowski space.
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).
However, time and space dimensions should not be viewed as exactly equivalent in Minkowski space-time. One can freely move in space but not in time. Thus, time and space coordinates are treated differently both in special relativity (where time is sometimes considered an imaginary coordinate) and in general relativity (where different signs are assigned to time and space components of spacetime metric).
The measurement of physical space has long been important. Geometry, the name given to the branch of mathematics which measures spatial relations, was popularized by the ancient Greeks, although earlier societies had developed measuring systems. The 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.
Geography is the branch of science concerned with identifying and describing the Earth, utilizing spatial awareness to try and understand why things exist in specific locations. Cartography is the mapping of spaces to allow better navigation, for visualization 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.
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 behavior, being an important factor in architecture, where it will impact on the design of buildings and structures, and on farming.
Ownership of space is not restricted to land. Ownership of airspace and of 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.
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.
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.
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 analyzing the perception of space are concerned with how recognition of an object\'s physical appearance or its interactions are perceived.
Other, more specialized 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.
Phobias include:
In anatomy, a space (or spatium) is an area of the human body with certain borders consisting of anatomic structures, e.g. the axillary space.
Wikiquote has a collection of quotations related to:
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia
