Number 408 (Story #3), December 23, 1998 by Phillip F. Schewe and Ben Stein RELATIVISTIC SLEIGH RIDE. The December 11 issue of Fermi News seeks to answer the perennial question of how Santa Claus can, in the course of a single night, deliver gifts to each of the world's 2 billion children. Even if a full-scale quantum computer were to work out the optimum course plan St. Nick must still cover a flight path of some 160 million km and stop at 800 million homes along the way. How does he do it? By traveling at close to the speed of light, of course, which, incidentally, also explains why (thanks to time dilation) Santa never seems to age. The Fermi News article helpfully addresses such questions as to how it is that the fat fellow can fit into Lorentz-contracted chimneys in the first place and how one can determine the color of the Doppler-shifted light emitted by Rudolph-the-rednosed-reindeer at sleigh velocities approaching the speed of light.