Worlds of David Darling
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  1. Where does space begin?
    "Space isn't remote at all. It's only an hour's drive away if your car could go straight upwards."
    – Fred Hoyle, Observer ( Sep. 9, 1979)
    (ASTRON) The part of the Universe lying outside of the limits of Earth's atmosphere. More generally, the volume in which all spatial bodies move.

  2. (PHYSICS) The three-dimensional theater in which things as we know them can exist or in which events can take place. In the Einsteinian worldview, space and time are united inextricably in a spacetime continuum and there is also the possibility of higher dimensions. See also fourth dimension.


  3. (MATH) In mathematics, a space is any unbounded or bounded extent. According to Euclidean geometry, space is uniform and infinite, so that we may talk of a line of infinite extent or a polygon of infinite area. In Riemannian geometry, however, all lines are of less than a certain, finite extent; and in Lobachevskian geometry, there is a similar maximum area.

    There are additionally many other types of space, most of them too abstract to imagine or to describe accurately in a few sentences. Generally, a mathematical space is a set of points with additional features. In a topological space every point has a collection of neighborhoods to which it belongs. In an affine space (see affine geometry), which is a generalization of the familiar concepts of a straight line, a plane, and ordinary three-dimensional space, a defining feature is the ability to fix a point and a set of coordinate axes through it so that every point in the space can be represented as a "tuple," or ordered set, of coordinates. Other examples of mathematical spaces include vector space, measure spaces, and metric spaces.

       • TOPOLOGY