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 because Minkowski time (10[1])is scaled by this quantity. The ratio of velocity to this quantity is denoted by beta. (10[2])By comparing interference patterns, this quantity was found not to depend on the direction of measurement in the Michelson-Morley experiment. (10[3])The mass-energy equivalence states (read slowly) rest energy equals mass times this quantity squared. For 10 points, name this universal (10[2])speed (10[1])limit equal to about three times ten to the eight meters per second. ■END■