Time zones, for most of human existence they didn’t matter. The most important points in time were sunrise, sunset, and noon when the Sun reached its highest point in the sky. Since the Earth is a sphere rotating on its axis as it orbits the Sun, these events are location dependent. For noon, every degree of longitude translates to ~4 minutes. For example, three degrees of longitude separate Boston and New York. Therefore, ‘local noon’ in Boston occurs ~12 minutes before local noon in New York.
While the concept of ‘local noon’ seems strange to us, for thousands of years it wasn’t a big deal. The creation of telegraph and railroad systems changed that. Suddenly, the fact that New York lagged Boston by 12 minutes became inconvenient. It was particularly confusing for the railroad companies. To simplify things, they created their schedules around a standard time. Unfortunately, each company chose its own local time as the standard. Junctions serving more than one railroad often displayed separate clocks, one for each company as well as one for the local time.
By the mid-19th century everyone recognized that time was a problem. The UK railways settled on a common ‘Railway Time’ that matched the time at Greenwich Royal Observatory. We now refer to this standard as Greenwich Mean Time (GMT). New Zealand took things a step further and established a nationwide New Zealand Mean Time (11:30 ahead of GMT).
In the US, things took a bit longer, but eventually four standard time zones were established. On 18 November 1883 railroad terminal clocks in major cities were reset to the new standard noon for their respective zone. As late as 1916 states and cities, especially those along time boarders, vacillated between local and standard times. In 1918, the US Congress passed the Standard Time Act formally adopting our time zones.
US Time Zone Map in 1913, courtesy of Wikipedia.
World Time Zones
As the telephone and telegraph knit the world more closely together, countries recognized that time was more than a national problem. It took decades, but eventually the world adopted Coordinated Universal Time (UTC). Under this system, countries set their time as an offset from GMT. For example, Eastern Standard Time is UTC-5:00. Contrary to the original plan, not every time zone is offset by an even number of hours. Iran operates at UTC+3:30 and Nepal at UTC+5:45. Additionally, boundaries for time zones often deviate from the 15° lines. China serves as an extreme example. Extending from 75°E to 135°E it should contain four time zones, but it’s only one. The entire country runs on UTC+8:00.
Current Map of World Time Zones courtesy of Wikipedia
I was going to tackle Daylight Savings Time, but mercifully I ran out of space. As always thanks for reading.
Armen
Note to Pay the Bills: While the Misaligned Series doesn’t focus on time zones, it does include time travel and elements of theoretical physics. How does theoretical physics fit into a Young Adult fantasy series about Welsh mythology? Learn more by reading a summary of the series here or find links to purchase books here.