East is west and west is east

Little Diomede Island (U.S.) in the Bering Strait (not the Aleutians, as I mistakenly wrote earlier) is reckoned to be some tens of thousands of kilometers west of Big Diomede Island (Russia), despite the obvious fact that Little Diomede is about four kilometers east of Big Diomede.

The reason for that is that in the state of nature, Europe is east of North America, which is east of Asia, which is east of Europe. So it makes no sense to ask "Is X east or west of Y?" unless we have instituted a convention of some sort.

One possible convention is: "X is east of Y if and only if the easterly great-circle course between them is shorter than the westerly one." That's the rule we apply in ordinary life, and by that rule, the Russian island is west of the U.S. one.

But the navigator's convention unwraps the globe at the 180 degree meridian, and says that the entire Eastern Hemisphere is east of the entire Western Hemisphere. Using this convention, the Russian island is east of the U.S. one.

And by the same token, Alaska, since it sticks into the Eastern Hemisphere, is the easternmost U.S. state as well as the westernmost and the northernmost. The southernmost state is Hawaii. Of the 48 contiguous states, the westernmost is Washington, the easternmost Maine, the southernmost Florida (thanks to Key West), and the northernmost Minnesota, due to a surveying error.


Paul Clapham said...

A surveying error? Wikipedia's article about the Northwest Angle says "Consequently the Northwest Angle is the result of 18th-century ignorance of geography." Of course it goes into a lot more detail...


Anton said...

Why not use the Date Line as the boundary between East and West Hemispheres? That way, the Aleutians reach 187° West and Siberia reaches 190° East.

John Cowan said...

Anton: The Date Line has no actual international status: it's just the consequence of the decisions that particular countries make about their time zones. Back in 1995, Kiribati got sick of dealing with inconsistent records and changed their time zones, with the result that the Date Line now passes east of Kiribati instead of through it.

We don't want such instabilities happening to longitude values.

D. Edgren said...

Uhh, John...

Little Diomede Island (U.S.) in the Aleutian Islands is reckoned to be some tens of thousands of kilometers west of Big Diomede Island (Russia)

The one factually wrong part of your otherwise really well-informed and thoughtful post is here in this passage. Little and Big Diomede are in fact quite a bit north of the chain (Aleutian Islands). The Diomedes are located west (and east, crediting your post for the correct way of looking at things in this strange part of the world) of Alaska's Seward Peninsula in the Bering Straits.

Been out there. I commanded a National Guard unit based in Kotzebue (go to Nome, turn right, cross the Arctic Circle and, hey, you're there) and there was a detachment on Little Diomede. It's just a basalt stack sticking several hundred feet almost straight up out of the water- the only flat place is on top, and the village is at the base of the cliifs on the water down about the scariest path I've ever been on. It's not the ends of the earth, but you can see them from there.

I stumbled on your blog Googling "northwest angle" for a project I'm working on. I've bookmarked it and will look in from time to time. Interesting stuff here.

D. Edgren
Wasilla, Alaska

John Cowan said...

Thanks, D. Edgren. Fixed.