Introduction

Abstract

Imagine that two people have been chosen to be observers in a scientific experiment involving two photons, or quanta of light. These photons originate from a single source and travel in opposite directions an equal distance halfway across the known universe to points where each will be measured or observed. Now suppose that before the photons are released, one observer is magically transported to a point of observation halfway across the known universe and the second observer is magically transported to another point an equal distance in the opposite direction. The task of the observers is to record or measure a certain property of each photon with detectors located at the two points so that the data gathered at each can later be compared.