34/44 In other words he will be moving. He will be moving in a straight line with uniform velocity. We might take this as the definition of a straight line. Namely, a straight line in the space of time-system {beta} is the locus of those points of {beta} which all intersect some one point-track which is a point in the space of some other time-system. Thus each point in the space of a time-system {alpha} is associated with one and only one straight line of the space of any other time-system {beta}. |