Question:
(1) When circumnavigating the globe, traveling eastward results in losing a day, while traveling westward leads to gaining a day. What is the reason for this phenomenon?
(2) What is the customary practice on board a ship regarding the day lost or gained during a circumnavigation of the globe?
(3) Does the day lost or gained impact the days of the week, or does it only affect the date, similar to the transition from the Old Style to the New Style of timekeeping?
Answer:
The sun appears to revolve around the Earth from east to west once every twenty-four hours due to the Earth’s rotation. It moves across fifteen degrees of the 360 degrees into which the Earth is divided in one hour. If someone travels around the world in the same direction as the sun, they gain time in proportion to the distance covered. For example, if they travel fifteen degrees, roughly equivalent to a thousand miles, within twenty-four hours, they would gain one hour. In other words, by staying with the sun for an extra hour, they effectively lengthen their day by one hour. If they continued this for twenty-four days, they would have extended each day by an hour. Although they wouldn’t lose any time, they would be one day ahead compared to when they started, based on the names assigned to the days of the week.
Conversely, if a traveler were going east at the same speed, they would lose an hour, meaning they would spend one hour less with the sun each day. Over twenty-four days, they would lose twenty-four hours, equivalent to a full day. In this case, they would effectively drop one day.
For a traveler on a ship journeying westward, if they reached the usual time change point on a Tuesday, they would call the following day, Thursday. If they were traveling eastward and reached the time change point on Tuesday, they would still call the next day, Tuesday. Alternatively, they could choose to add or drop parts of two days.
Providence and custom have established this point of time change in the Pacific Ocean. Travelers crossing from the east coast of Asia to the west coast of America find that they are aligned with the local count of the days of the week. However, ships crossing the Pacific Ocean westward drop a day, while those traveling eastward add a day.
It is important to note that neither the day of the week nor the date is affected by this change. If travelers stubbornly adhere to their own time, they would be out of sync with the rest of the world. However, if they remain in harmony with natural and everyday factors, they would have no issue losing or gaining days or observing a day.
