PDA

View Full Version : Special Relativity to blow your mind


franznietzsche
Dec16-03, 07:53 PM
Here's a few kickers for those of you who don't know a lot about the mathematics of relativity:

The locus of all points equidistant from the origin is a four dimensional hyberbola given by:

d^2=(y_1-x_1)^2+(y_2-x_2)^2+(y_3-x_3)^2-c^2(y_4-x_4)^2

where c is the speed of light. Also the cross section of this perpendicular to the time axis (x_4) is a sphere, the euclidean locus of equidistant points.

the reason the -c^2 is in the equation is the Minkowski metric which also determines the lorentz transformation that makes inertia increase as velocity increases etc. Hope someone else finds this tidbit entertaining.

chroot
Dec16-03, 08:06 PM
What you've posted is a sort of ugly form of the "line element," which defines the distance between two neighboring points in spacetime. In special relativity, the line element is most succinctly expressed as

ds^2 = \eta_{\mu\nu} dx^\mu dx^\nu

where \eta is the metric of Minkowski (flat) spacetime.

- Warren