Looking back to the time when clocks were non-existent, people used different devices such as sundials and water clocks to tell what time it is. In the 17th century, the pendulum was invented but it wasn’t that accurate especially when being used at sea. That is the reason why the Chronometer was introduced. It measured the time more accurately even when there is movement and in varying conditions as well.
When well-regulated clocks were invented, each city set the time depending on the sunrise, or their own solar time. They did not pay much attention if the time was not accurate compared to other places since it was of long travel times and lack of long-distance communications. But, have you ever wondered how having a universal and standard time zone began?
A major problem arose when railways and long-distance communication was starting to be developed. For example, each train station sets its own time and the railroad companies found it difficult to coordinate train schedules which led to confused passengers. They found calculating a coordinated time a great challenge and critical to ensuring people wouldn’t miss their train. Standard time was also needed so that conductors could make sure that the trains using the same tracks wouldn’t crash. A miscalculation of even just one minute could lead to a deadly collision.
A railroad engineer named William Frederick Allen helped in to create time zones for America. He proposed four time zones which were divided roughly at the 75th, 90th, 105th, and 130th meridians west of Greenwich. A General Time Convention approved that “railroad time” would replace the local time. As a result, people started setting their clocks according to the railroad time, even though it wasn’t an official government-sanctioned requirement.
In 1878, a Canadian railway engineer named Sir Sandford Fleming developed a system of worldwide time zones that we still use up to this date. His proposal is that the world would be divided into 24 time zones – each spaced 15 degrees of longitude from each other. This is because the Earth’s rotation takes 24 hours and there are 360 degrees of longitude, so in each hour, the Earth rotates 1/24th of a circle or 15 degrees. On November 18, 1883, the railroad companies in the US began using this standard time zone.
In 1884, an International Meridian Conference was held, where 22 nations met in Washington, D.C. to standardize the time across countries and to select the Prime Meridian. The Prime Meridian is the designated zero degrees starting point from which all other longitudes are measured. At that time the Greenwich Meridian was also formally established as the prime meridian and the Greenwich Mean Time (GMT) as the standard time of the world. This means that the time zone will change by an hour every 15 longitudinal degrees, which will create 24 time zones around the world. The time zones start and end at the Prime Meridian. One factor that contributed to choosing the Greenwich Meridian as the prime meridian is the Greenwich Observatory’s accuracy and reliability in giving navigational data.
As the years passed, some governments have adopted, changed, and ignored the Greenwich Mean Time (GMT). Despite the outcome of the International Meridian Conference in 1884 having set GMT as the universal reference standard. For example, the French still continued to treat Paris as the prime meridian until 1911.
In the United States, most of the states began to adhere to the Eastern, Central, Mountain, and Pacific time zones but it was not mandatory until the Congress passed the Standard Time Act of March 19, 1918. The act had also included daylight savings time. Daylight savings adjust the time an hour ahead of the standard time to achieve longer evening daylight, especially during summer.
In 1966, the Uniform Time Act was passed by the US Congress which aimed to force national standards for when daylight savings started and ended. Even then it wasn’t fully mandated for each state and to this day Hawaii and Arizona are notable exceptions who do not observe daylight savings.
In 1972, GMT was replaced by Coordinated Universal Time (UTC) as the world’s time standard. It is managed by highly precise atomic clocks and timing clocks around the world are highly synchronized. In addition, UTC allows for leap seconds to adjust the atomic clock time to the variances of the earth’s rotation.
In the present time, nations use standard time zones, but some countries have deviations of 30 to 45 minutes from the standard time. The United States and its territories cover a total of nine time zones which follow the standard. On the other hand, some countries do not follow the 24 standard time zones. One example is China which uses a single time zone even though their territory covering 5 geographic time zones.
Having a universal time standard truly helped the world evolve and develop technologically. It’s hard to imagine in our modern day world not knowing the current time anywhere in the world and having it be accurate to the second. These standards have been a cornerstone of the internationalization of travel and economic development.