By: Anagabriela Medina
For those of us who travel a lot or have family and friends around the world, you know the struggle of trying to understand time zones.
So, why exactly do they exist? Well, let’s bring in some science for this. If you remember, the Earth spins on an imaginary axis with each complete rotation taking 24 hours to complete, creating what we know as a full day. Only certain parts of the Earth receive sunlight as it makes its full rotation, which it was know as day and night. So, you can clearly imagine what would happen if time zones didn’t exist. Twelve in the afternoon could be bright and sunny for some parts of the world, while others would be in pitch black. In short, they are muy importante!
It was the International Meridian Conference that took place on October 1884 that established what we now know as the Greenwich Mean Time (GMT), the world’s time standard and prime meridian. Greenwich is the starting point for all the time zones around the world. If you head west from the GMT, you will lose an hour for every 15-degree sections of the Earth. The opposite is also true if you decide to head east instead by gaining an hour for every 15 degrees. For example, if it was noon in Greenwich, and a country to the east stated their time as GMT +6 (or sometimes UTC for Coordinated Universal Time), then it’s 6 p.m. in that country. And since there is 24 hours in a day, there is also 24 different time zones excluding the International Date Line.
The International Date Line is what separates each day, 180 degrees both east and west of Greenwich, so things can get a little more complicated if you cross it some time during your travels. You might end up gaining or losing an entire day!
Just like the United States, which has a total of 6 time zones, other countries may also have multiple time zones depending on how large or small it is. By including all of its territories, France has the most at 12 time zones. China only has one time zone.