In a way, time travel does exist. Just hop on a plane from Montreal to Vancouver, and you jump back three hours. Or better yet, fly in the other direction to Auckland, and find yourself 18 hours in the future. Of course, we owe these time differences to the Earth鈥檚 rotation, but also to the human-decided lines that identify various time zones. (This subject is, in fact, very personal to me because I am currently writing this at 5:30 in the morning due to the infamous jetlag most of us have experienced at some time.)
The Relativity of Time
Prior to 1878, time was organized on a purely local basis. Most cities and towns would base their time on the sun, the local solar time. In these smaller locales, a well-known clock, typically centrally located would display the time. Individuals would set their pocket watches or clocks at home according to these centralized clocks. However, this method of timekeeping was challenged in when, in New England, two trains that were headed towards one another, on the same track, collided. This collision could have been prevented had the conductors had the same time displayed on their watches. This disaster resulted in the death of 14 passengers and injured 17 more, shining a spotlight on the perils of not having a standardized railway time. Standardizing time on North American railways proved to be far more difficult than anticipated, so the industry was at somewhat of a standstill for 20 years.
In 1878, Sir Sandford Fleming, a Canadian railroad engineer, had a revolutionary idea. Inspired by an , where a mix-up of A.M. and P.M. caused him to miss his train, Fleming came up with the idea of creating a 24-hour clock (military time). After this proposition, Fleming conceived of implementing 24 time zones across the world. These time zones, according to Fleming, would each be 15 degrees of longitude wide 鈥� more simply, an hour wide. (The math here is that the Earth rotates 360潞 in a day, and divided by 24, you get 15潞. Thus, equal time zones!) While initially facing some pushback, in 1883, United States railroad companies decided to operate on four time zones 鈥� and soon after, the rest of the world followed suit.
Beyond Fleming
The key player in this tale is the . In the same way that the equator divides Earth into the Northern and Southern Hemispheres, the Prime Meridian divides the Earth into Eastern and Western Hemispheres. Basically:
0潞 Latitude is the Equator and its lines run horizontally
0潞 Longitude is the Prime Meridian and its lines run vertically
The Prime Meridian is significant because it serves as the reference point for the world鈥檚 timekeeping mechanisms as we know them. GMT (Greenwich Mean Time) is the basis of the standard time zone system. So, EST (Eastern Standard Time) is sometimes written as GMT-5, because it is five hours behind GMT.
While Fleming鈥檚 idea for creating 24 perfectly even time zones was logical and seemed widely supported at the time, it did not remain fully applicable for long. Although there are technically 24 standard time zones, today there are about 38-40 recognized time zones worldwide. This discrepancy largely accounts for countries that do not follow whole-hour offsets from GMT, such as India and Nepal, which operate at GMT+5:30 and GMT+5:45 respectively.
In India鈥檚 case 鈥� and similarly in China 鈥� the decision to maintain a single national time zone was driven by political leadership with the intention of unifying the country under one standard time. India鈥檚 time zone has historical roots in British colonial rule. However, some also argue that this unique time zone helps to balance sunrise and sunset times across the country. Interestingly, in , this unique time zone has been subject to controversy in the context of impacting children鈥檚 health. One study published in argued that children living in parts of the country with later sunsets tend to go to bed later, yet still have to wake up at the same time as their counterparts for whom the sun sets up to two hours earlier. This has been said to lead to poorer educational outcomes due to a lack of sleep.
A little bit closer to home, we have another example. which is GMT-3:30. This anomaly occurred because the province was not a part of Canada when time zones were first created and standardized. Laying between meridian lines, the government set the local standard time to GMT-3:30 and it was never shifted to adhere to Canadian guidelines once they joined the country to preserve local identity, and to avoid disruption. Interestingly, in 1963, the provincial government attempted to shift the province to Atlantic Time, but there was public opposition, and the resolution never passed.
While scientists living in Antarctica simply use GMT, following Fleming鈥檚 logic would divide the continent into 24 tiny time zones. What a way to spend New Year鈥檚 Eve, celebrating the New Year every hour, all day long. Now that鈥檚 a party!
Eva Kellner is a recent graduate from the Faculty of Arts and Science, with a major in Environment. Her research interests include urban green spaces, urban agriculture, and outdoor community spaces - all as promoters of climate resilience among city-dwellers.
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