SPACE is the boundless three-dimensional extent in which objects and events have relative position and direction. Physical space is often conceived in three linear dimensions , although modern physicists usually consider it, with time , to be part of a boundless four-dimensional continuum known as spacetime . The concept of space is considered to be of fundamental importance to an understanding of the physical universe . However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework . Debates concerning the nature, essence and the mode of existence of
space date back to antiquity; namely, to treatises like the _Timaeus _
of
In the 19th and 20th centuries mathematicians began to examine
geometries that are non-Euclidean , in which space is conceived as
_curved_, rather than _flat_. According to
CONTENTS * 1 Philosophy of space * 1.1 Leibniz and Newton
* 1.2 Kant
* 1.3
* 2 Mathematics * 3
* 3.1
* 4 Spatial measurement * 5 Geographical space * 6 In psychology * 7 See also * 8 References * 9 External links PHILOSOPHY OF SPACE LEIBNIZ AND NEWTON In the seventeenth century, the philosophy of space and time emerged
as a central issue in epistemology and metaphysics . At its heart,
Newton took space to be more than relations between material objects
and based his position on observation and experimentation . For a
relationist there can be no real difference between inertial motion ,
in which the object travels with constant velocity , and non-inertial
motion , in which the velocity changes with time, since all spatial
measurements are relative to other objects and their motions. But
Newton argued that since non-inertial motion generates forces , it
must be absolute. He used the example of water in a spinning bucket
to demonstrate his argument.
KANT In the eighteenth century the German philosopher Immanuel Kant developed a theory of knowledge in which knowledge about space can be both _a priori_ and _synthetic _. According to Kant, knowledge about space is _synthetic_, in that statements about space are not simply true by virtue of the meaning of the words in the statement. In his work, Kant rejected the view that space must be either a substance or relation. Instead he came to the conclusion that space and time are not discovered by humans to be objective features of the world, but imposed by us as part of a framework for organizing experience. NON-EUCLIDEAN GEOMETRY Main article:
Euclid's _Elements_ contained five postulates that form the basis for
Euclidean geometry. One of these, the parallel postulate , has been
the subject of debate among mathematicians for many centuries. It
states that on any plane on which there is a straight line _L1_ and a
point _P_ not on _L1_, there is exactly one straight line _L2_ on the
plane that passes through the point _P_ and is parallel to the
straight line _L1_. Until the 19th century, few doubted the truth of
the postulate; instead debate centered over whether it was necessary
as an axiom, or whether it was a theory that could be derived from the
other axioms. Around 1830 though, the Hungarian
TYPE OF GEOMETRY NUMBER OF PARALLELS SUM OF ANGLES IN A TRIANGLE RATIO OF CIRCUMFERENCE TO DIAMETER OF CIRCLE MEASURE OF CURVATURE HYPERBOLIC Infinite < 180° > π < 0 EUCLIDEAN 1 180° π 0 ELLIPTICAL 0 > 180° < π > 0 GAUSS AND POINCARé
Although there was a prevailing Kantian consensus at the time, once
non-Euclidean geometries had been formalised, some began to wonder
whether or not physical space is curved.
EINSTEIN
In 1905,
Subsequently,
MATHEMATICS Main article:
In modern mathematics spaces are defined as sets with some added structure. They are frequently described as different types of manifolds , which are spaces that locally approximate to Euclidean space, and where the properties are defined largely on local connectedness of points that lie on the manifold. There are however, many diverse mathematical objects that are called spaces. For example, vector spaces such as function spaces may have infinite numbers of independent dimensions and a notion of distance very different from Euclidean space, and topological spaces replace the concept of distance with a more abstract idea of nearness. PHYSICS Many of the laws of physics, such as the various inverse square laws , depend on dimension three. In physics, our three-dimensional space is viewed as embedded in
four-dimensional spacetime , called
CLASSICAL MECHANICS Main article:
CLASSICAL MECHANICS F = m a {displaystyle {vec {F}}=m{vec {a}}}
* History * Timeline Branches * Applied
* Celestial
* Continuum
* Dynamics
*
Fundamentals *
* kinetic * potential *
* Mechanical power * Mechanical work *
Moment *
Formulations * NEWTON\\'S LAWS OF MOTION * ANALYTICAL MECHANICS *
Core topics *
* Inertial /
* Motion (linear )
* Newton\'s law of universal gravitation
* Newton\'s laws of motion
*
* dynamics * Euler\'s equations *
Rotation *
* reactive *
*
Scientists * Galileo
* Newton
* Kepler
* Horrocks
* Halley
* Euler
* d\'Alembert
* Clairaut
* Lagrange
* Laplace
* Hamilton
* Poisson
*
* v * t * e
RELATIVITY Main article:
Before
In addition, 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 ). Furthermore, in Einstein\'s general theory of relativity , it is postulated that space-time is geometrically distorted- _curved_ -near to gravitationally significant masses. One consequence of this postulate, which follows from the equations of general relativity, is the prediction of moving ripples of space-time, called gravitational waves . While indirect evidence for these waves has been found (in the motions of the Hulse–Taylor binary system, for example) experiments attempting to directly measure these waves are ongoing. COSMOLOGY Main article:
Relativity theory leads to the cosmological question of what shape
the universe is, and where space came from. It appears that space was
created in the
SPATIAL MEASUREMENT Main article:
The measurement of _physical space_ has long been important. 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. 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 in which the speed of light plays the role of a fundamental constant of nature. GEOGRAPHICAL SPACE See also:
Geographical space is often considered as land, and can have a
relation to ownership usage (in which space is seen as property or
territory). 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
IN PSYCHOLOGY Psychologists first began to study the way space is perceived in the middle of the 19th century. Those now concerned with such studies regard it as a distinct branch of psychology . Psychologists analyzing the perception of space are concerned with how recognition of an object's physical appearance or its interactions are perceived, see, for example, visual space . 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 as well as simply one's idea of personal space . Several space-related phobias have been identified, including agoraphobia (the fear of open spaces), astrophobia (the fear of celestial space) and claustrophobia (the fear of enclosed spaces). The understanding of three-dimensional space in humans is thought to be learned during infancy using unconscious inference , and is closely related to hand-eye coordination . The visual ability to perceive the world in three dimensions is called depth perception . SEE ALSO *
* Book:
*
REFERENCES * ^ "space - physics and metaphysics". _Encyclopædia Britannica_.
* ^ Refer to Plato's _Timaeus_ in the Loeb Classical Library,
EXTERNAL LINKS * Seth Shostak on |