missgrace410 wrote:What are some standard arguements that time is the fourth dimension, or just a dimension in general?
In relativety theories Time is used as a fourth dimension, since time is not a length there is a unit-mismatch which is compensated by multiplying time with the velocity of light (c). In relativity theory it is often used as the zeroth component of the space-time 4-vector, often also multiplied by i (= root(-1)) to make the relation x[sub]μ[/sub]x[sup]μ[/sup] = 0 stands for the expansion of the light sphere in normal coördinates this reads x[sup]2[/sup] + y[sup]2[/sup] + z[sup]2[/sup] = t[sup]2[/sup] (c often scaled to 1).
This point of view simply makes it an excelent mathematical tool, as said much of the 4th dimension is a mathematical generalisation of three dimensional mathematics, wheter one views time above as a true dimension is a matter of opinion, the mathematics suggest when one travels at speed greater then c (the speed of light) one travels back in time (as tachyons do), dispite that what is suggested by sci-fi stories.
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