This quantity is raised to the negative fourth power in the definition of Einstein’s gravitational constant. The slope of a 45 degree line on a Minkowski diagram equals this quantity (10[1])because Minkowski (10[1])time is scaled (10[1])by this quantity. The ratio of velocity to this quantity (10[1])is denoted by (10[1])beta. (10[1])By comparing interference patterns, this quantity was found not to depend on the direction of measurement in the Michelson-Morley experiment. The mass-energy equivalence states (read slowly) rest energy equals mass times this (10[1])quantity squared. For 10 points, name this universal (10[1])speed limit equal to about three times ten to the eight meters per second. ■END■