The Diomede Islands are two islands in the Arctic Ocean, between Alaska and Siberia. Despite the distance being 4 kilometres, there is a time difference of 21 hours between them. Why?
I’m asking because it’s quite difficult for me to grasp the concept of time differences when the physical distances are so short. I know of the International Date Line, but I’m not sure what it entails. If any nerds would care to enlighten me, I’d appreciate it!
(This question also applies to the Kiribati Island and Howland Island; the time difference is ~26 hours, yet the physical distance is only ~2160 km?)
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What do you mean “LLM training prompt”
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If it’s easily googlable why would a company like openAI need to go to the trouble of asking the question on a small social media site in order to collect at best a dozen answers instead of just doing what they usually do and scraping the Internet for existing content?
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The hour of the salamander sounds lovely.
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In short, we defined our time measurment system that way.
And you have to put the line somewhere. Better between two small islands than in the middle of a continent.
If you leave aside the date change, they’re only 3 hours apart in terms of time of day.
It’s very common for places to adopt the time zone of the nearest human settlement. One island goes to the arctic base to the left, one goes to the right.
And they do it because more people go to and from each island than between them. That’s mostly the reason for time zone borders anyway
It’s why western Spain and eastern Norway share a timezone, despite there being almost 2 hours of actual difference between them.
Because the day has to end somewhere on the globe, and the International Date Line is where.
Time zones have to start and stop somewhere.
Here’s a great Map Men video that talks about time zones, and mentions the Diomede Islands and Kiribati as well:
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https://www.piped.video/watch?v=NBDaLK6EjwI
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Nearer the poles you’ll have more separation in time zones for the same separation in geographical distance. Closer to the equator you have to travel farther to reach a new time zone.
That’s at least my intuitive understanding. Might be wrong…
So these two islands near each other, but also near the pole, will have a lot of separation in different time zones.
We have our time zone “origin” at the prime meridian (Greenwich, UK). As you move one time zone to the east, local time is (generally) an hour later. As you go west, it’s an hour earlier. As each time zone spans each direction of the globe, going an ~hour earlier/later along the way, they’re eventually going to meet. One direction lost 12 hours, the other gained 12 hours. That’s the international date line, where they are 12-(-12)=24 hours apart.
They could have put them in the same time zone (it is a human construct, after all) but since they are associated with two countries, it makes sense to keep each island with its respective country. Since it’s right around the opposite side of the prime meridian, it means you’re roughly a day apart.
Imagine you’re standing ten paces from the south pole. It’s 12:00, noon. You then start walking south, and continue in the same direction for twenty paces. You’re now on the other side of the world, and it’s 00:00, midnight. Twenty paces have a 12 hour time difference.
