Fractal, in mathematics, a
geometric shape that is complex and detailed in structure at any level of
magnification.
Often fractals are self-similar—that
is, they have the property that each small portion of the fractal can be viewed
as a reduced-scale replica of the whole.
One example of a fractal is the "snowflake"
curve constructed by taking an equilateral triangle and repeatedly erecting
smaller equilateral triangles on the middle third of the progressively smaller
sides.
Theoretically, the result would be a figure of finite
area but with a perimeter of infinite length, consisting of an infinite number
of vertices.
In mathematical
terms, such a curve cannot be differentiated (see Calculus).
Many such
self-repeating figures can be constructed, and since they first appeared in the
19th century they have been considered as merely bizarre.
A turning point in the study of fractals came with the
discovery of fractal geometry by the Polish-born French mathematician Benoit B.
Mandelbrot in the 1970s.
Mandelbrot adopted a
much more abstract definition of dimension than that used in Euclidean
geometry, stating that the dimension of a fractal must be used as an exponent
when measuring its size.
The result is that a fractal cannot be treated as
existing strictly in one, two, or any other whole-number dimensions.
Instead, it must be handled mathematically as though it
has some fractional dimension. The "snowflake" curve of fractals has
a dimension of 1.2618.
Fractal geometry is not simply an abstract development.
A coastline, if measured down to its least irregularity, would tend toward
infinite length just as does the "snowflake" curve.
Mandelbrot has
suggested that mountains, clouds, aggregates, galaxy clusters, and other
natural phenomena are similarly fractal in nature, and fractal geometry's
application in the sciences has become a rapidly expanding field.
Benoit B. Mandelbrot founded a new branch of mathematics, fractal
geometry.
In conventional geometry, an object’s dimension is expressed in whole
numbers; a line, for example, is one-dimensional and plane has two dimensions.
In fractal geometry, objects may have "fractional" dimensions.
For example, a fractal image may have a border that is infinitely
detailed, and thus, a dimension between one and two. [1]
In addition, the beauty of fractals has made
them a key element in computer graphics.
Fractals have also been used to compress still and video
images on computers.
In 1987, English-born mathematician Dr. Michael F.
Barnsley discovered the Fractal TransformTM which automatically
detects fractal codes in real-world images (digitized photographs).
The discovery spawned fractal image compression, used in
a variety of multimedia and other image-based computer applications.
Contributed By:
Benoit B. Mandelbrot
[2]
[1]"Benoit B. Mandelbrot," Microsoft® Encarta® Encyclopedia 99. ©
1993-1998 Microsoft Corporation. All rights reserved.
[2]"Fractal," Microsoft® Encarta® Encyclopedia 99. © 1993-1998 Microsoft
Corporation. All rights reserved.