World Lines As A Tool To Describe Events
A one-dimensional line or curve can be represented by the coordinates as a function of one parameter. Each value of the parameter corresponds to a point in spacetime and varying the parameter traces out a line. So in mathematical terms a curve is defined by four coordinate functions (where usually denotes the time coordinate) depending on one parameter . A coordinate grid in spacetime is the set of curves one obtains if three out of four coordinate functions are set to a constant.
Sometimes, the term world line is loosely used for any curve in spacetime. This terminology causes confusions. More properly, a world line is a curve in spacetime which traces out the (time) history of a particle, observer or small object. One usually takes the proper time of an object or an observer as the curve parameter along the world line.
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Famous quotes containing the words world, lines, tool, describe and/or events:
“Man is made of the same atoms the world is, he shares the same impressions, predispositions, and destiny. When his mind is illuminated, when his heart is kind, he throws himself joyfully into the sublime order, and does, with knowledge, what the stones do by structure.”
—Ralph Waldo Emerson (1803–1882)
“I am so tired of taking to others
translating my life for the deaf, the blind,
the “I really want to know what your life is like without giving up any of my privileges
to live it” white women
the “I want to live my white life with Third World women’s style and keep my skin
class privileges” dykes”
—Lorraine Bethel, African American lesbian feminist poet. “What Chou Mean We, White Girl?” Lines 49-54 (1979)
“Is it not possible that an individual may be right and a government wrong? Are laws to be enforced simply because they were made? or declared by any number of men to be good, if they are not good? Is there any necessity for a man’s being a tool to perform a deed of which his better nature disapproves?”
—Henry David Thoreau (1817–1862)
“If you describe things as better than they are, you are considered to be a romantic; if you describe things as worse than they are, you will be called a realist; and if you describe things exactly as they are, you will be thought of as a satirist.”
—Quentin Crisp (b. 1908)
“By the power elite, we refer to those political, economic, and military circles which as an intricate set of overlapping cliques share decisions having at least national consequences. In so far as national events are decided, the power elite are those who decide them.”
—C. Wright Mills (1916–1962)