Physics in Spacetime
The equations of special relativity can be written in a manifestly covariant form. The position of an event in spacetime is given by a contravariant four vector with components:
We define x0 = ct so that the time coordinate has the same dimension of distance as the other spatial dimensions; so that space and time are treated equally. Superscripts are contravariant indices in this section rather than exponents except when they indicate a square (it should be clear from the context). Subscripts are covariant indices which also range from zero to three, as with the four-gradient of a scalar field φ:
Read more about this topic: Special Relativity
Famous quotes containing the words physics in and/or physics:
“Physics investigates the essential nature of the world, and biology describes a local bump. Psychology, human psychology, describes a bump on the bump.”
—Willard Van Orman Quine (b. 1908)
“The pace of science forces the pace of technique. Theoretical physics forces atomic energy on us; the successful production of the fission bomb forces upon us the manufacture of the hydrogen bomb. We do not choose our problems, we do not choose our products; we are pushed, we are forced—by what? By a system which has no purpose and goal transcending it, and which makes man its appendix.”
—Erich Fromm (1900–1980)