The 1964 Experiment That Checked the Validity of the Principle

Multiple Choice

The 1964 experiment that checked the validity of the principle of the constancy of lightspeed involved

A) a NASA satellite that emitted radiation both forward and backward.
B) comparison of the speeds of two parallel light beams, one emitted on Earth and other emitted from a jet airplane.
C) the emission of light from two atoms that were at rest on Earth.
D) jet planes carrying a highly accurate atomic clock, and a similar clock on Earth.
E) a fast- moving sub- atomic particle that emitted radiation both forward and backward.