Brief Summary
This video explains the International Date Line (IDL), a line that divides the world into two hemispheres and marks the beginning and end of calendar days. The IDL is not a straight line but zigzags around the globe due to political and economic reasons. The video explores the history of the IDL, its arbitrary nature, and the various anomalies that exist due to its shifting boundaries.
- The IDL is an imaginary line that marks the 24-hour time zone shift.
- The IDL's location is arbitrary and has been shifted multiple times due to political and economic reasons.
- The IDL's current shape is a result of historical events and the need to keep certain territories within the same calendar day.
The International Date Line: Why It's So Stupid
The video begins by explaining the concept of the International Date Line (IDL) and how it divides the world into two hemispheres, the Western and Eastern Hemispheres. The IDL is also the line where calendar days begin and end, with a 24-hour time difference between the two sides. This means that crossing the IDL from east to west results in adding 24 hours to your time, skipping forward a full calendar day. Conversely, crossing from west to east subtracts 24 hours, moving you back a full calendar day. The video uses examples of flights between Los Angeles and Tokyo to illustrate this time zone chaos.
Why the IDL Isn't a Straight Line
The video then explains why the IDL is not a straight line and instead zigzags around the globe. The reason for this is that the IDL's location is not based on a simple geographical division but rather on political and economic considerations. The video highlights several examples of how the IDL has been shifted over time to accommodate different countries' needs.
The Philippines and the IDL
The video discusses the Philippines' unique relationship with the IDL. For centuries, the Philippines were administratively assigned to the Viceroyalty of New Spain, which was centered on Mexico. To keep the Philippines within the same calendar day as Mexico, the Spanish authorities treated the Philippines as if they were on the eastern side of the IDL, despite their actual location in the western Pacific. This resulted in the Philippines being one calendar day behind their Asian neighbors for over 300 years. In 1844, the Spanish authorities shifted the Philippines to the western side of the IDL, effectively deleting a day from their calendar.
Russia, Alaska, and the IDL
The video then focuses on the IDL's impact on Russia and Alaska. The IDL initially ran through a part of the Russian Empire in Siberia, separating Russian Alaska from the rest of the empire. To avoid having different calendar days within the empire, the Russians initially interpreted the IDL to carve eastwards, keeping Alaska west of the line. However, when the United States purchased Alaska from Russia in 1867, the US shifted the IDL westwards to put Alaska east of the line, aligning it with the rest of the American time zones.
The IDL in the Pacific
The video continues by exploring the IDL's complex history in the Pacific. After World War II, the US assumed control over a vast area of the Pacific, including the remote atoll of Kwajalein in the Marshall Islands. To keep Kwajalein within the same calendar day as Hawaii, the US shifted the IDL west of Kwajalein in 1945. However, after the Marshall Islands gained independence in 1986, they shifted Kwajalein back to the western side of the IDL to avoid having a different calendar day from the rest of the country.
Kiribati and the IDL
The video then discusses the most significant anomaly of the IDL: the giant hook that cleaves the line far to the east. This anomaly is due to the island nation of Kiribati. Before Kiribati's independence in 1979, its islands were divided between British and American colonies, with the western islands on the western side of the IDL and the eastern islands on the eastern side. After independence, Kiribati straddled the IDL, with its eastern and western islands on opposite ends and in different days. To avoid this administrative difficulty, Kiribati shifted the IDL eastwards in 1994, keeping the entire country within the same calendar day.
Samoa and the IDL
The video concludes by examining the IDL's impact on Samoa and American Samoa. These two islands, only 120 miles apart, are chronologically a full 24 hours apart due to the IDL's position. This anomaly dates back to the 19th century when American merchants convinced the rulers of Samoa to shift their islands to the eastern side of the IDL to facilitate trade with the American West Coast. In 2011, Samoa shifted back to the western side of the IDL to align themselves with their major trading partners in Australia and New Zealand. This shift resulted in Samoa being 24 hours ahead of American Samoa, which remains a US territory.
The video concludes by highlighting the potential for future changes to the IDL, particularly regarding the Cook Islands and Niue, which are both east of the IDL and 24 hours behind New Zealand. The video suggests that the IDL may be redrawn in the future to keep these islands within the same calendar day as New Zealand.
