Double Light Speed: History, Confusion, and Recent Applications to High Speed Trading

Abstract

Every physicist and most non-physicists have heard that no object or signal can move faster than the speed of light in a vacuum c. However, when we study the literature on Einstein's special relativity theory carefully, we will find a less well-known 2c speed limit (double light speed limit) that is also fully consistent with special relativity theory. In this paper we will provide a chronological historical overview of the literature on the 2c speed limit and then show how this speed limit has recently started to play a role in financial markets via high-speed trading. This does not conflict in any way with the concept that nothing can move faster than the speed of light. However, even in the special relativity literature we have described here, there are several different velocities, depending on who the observer is and what the speed is relative to.

Keywords: Special relativity theory, speed limit, Einstein's velocity addition theorem, Lorentz velocity transformation, Galilean velocity addition, mutual velocity, exterior relative velocity, closing speed, high-speed trading