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 child-rearing years are relatively short in our increased life span. It is hard for young women caught between diapers and formulas to believe, but there are years and years of freedom ahead. I regret my impatience to get on with my career. I wish I’d relaxed, allowed myself the luxury of watching the world through my little girl’s eyes.”
—Eda Le Shan (20th century)
“It is the Late city that first defies the land, contradicts Nature in the lines of its silhouette, denies all Nature. It wants to be something different from and higher than Nature. These high-pitched gables, these Baroque cupolas, spires, and pinnacles, neither are, nor desire to be, related with anything in Nature. And then begins the gigantic megalopolis, the city-as-world, which suffers nothing beside itself and sets about annihilating the country picture.”
—Oswald Spengler (1880–1936)
“The first tool I step on
Turned into a weapon.”
—Robert Frost (1874–1963)
“But these words seemed to them an idle tale, and they did not believe them.”
—Bible: New Testament, Luke 24:11.
Response to women who describe the empty tomb of Jesus.
“That’s the great danger of sectarian opinions, they always accept the formulas of past events as useful for the measurement of future events and they never are, if you have high standards of accuracy.”
—John Dos Passos (1896–1970)