  Modern physics has demonstrated that matter behaves very differently as it
approaches the speed of light. This paper explores the implications of modern
physics to the operation and regulation of financial markets. Information
cannot move faster than the speed of light. The geographic separation of market
centers means that relativistic considerations need to be taken into account in
the regulation of markets. Observers in different locations may simultaneously
observe different best prices. Regulators may not be able to determine which
transactions occurred first, leading to problems with best execution and
trade-through rules. Catastrophic software glitches can quantum tunnel through
seemingly impregnable quality control procedures.
