When and how were the worlds time zones established, and how was their accuracy calculated?
In the latter part of the nineteenth century, a variety of meridians were used for longitudinal reference by various countries. For a number of reasons, the Greenwich meridian was the most popular of these. At least one factor in this popularity was the reputation for reliability and correctness of the Greenwich Observatory’s publications of navigational data. It became clear that shipping would benefit substantially from the establishment of a single “prime” meridian, and the subject was finally resolved in 1884 at a conference held in Washington, where the meridian passing through Greenwich was adopted as the initial or prime meridian for longitude and timekeeping. Given a 24 hour day and 360 degrees of longitude around the earth, it is obvious that the world’s 24 time zones have to be 15 degrees wide, on average. The individual zone boundaries are not straight, however, because they have been adjusted for the convenience and desires of local populations. Interestingly, the standard
