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.
Read more about this topic: World Line
Famous quotes containing the words world, lines, tool, describe and/or events:
“The world began without man, and it will end without him.”
—Claude Lévi-Strauss (b. 1908)
“We stand in the tumult of a festival.
What festival? This loud, disordered mooch?
These hospitaliers? These brute-like guests?
These musicians dubbing at a tragedy,
A-dub, a-dub, which is made up of this:
That there are no lines to speak? There is no play.”
—Wallace Stevens (1879–1955)
“A broken altar, Lord, thy servant rears,
Made of a heart, and cemented with tears:
Whose parts are as thy hand did frame;
No workman’s tool hath touched the same.”
—George Herbert (1593–1633)
“Modern man, if he dared to be articulate about his concept of heaven, would describe a vision which would look like the biggest department store in the world, showing new things and gadgets, and himself having plenty of money with which to buy them. He would wander around open-mouthed in this heaven of gadgets and commodities, provided only that there were ever more and newer things to buy, and perhaps that his neighbors were just a little less privileged than he.”
—Erich Fromm (1900–1980)
“Reporters are not paid to operate in retrospect. Because when news begins to solidify into current events and finally harden into history, it is the stories we didn’t write, the questions we didn’t ask that prove far, far more damaging than the ones we did.”
—Anna Quindlen (b. 1952)