A fire dancer performs on a beach in Samoa.

Story highlights

Samoa is 101 miles (164 kilometers) west of American Samoa

But Samoa marks the new year a whole day before its neighbor

The international date line swings more than 1,500 miles east for Kiribati

Some Alaskans have to celebrate 2013 a day after Russian neighbors to the north

CNN  — 

Just 101 miles separate Samoa and American Samoa.

But one will be the first country in the world to welcome the New Year; the other will have to wait a full day.

Samoans can thank the very crooked international date line for their license to party early.

The line is an imaginary one dreamed up to help with global time-keeping.

It splits the globe into two – so when it’s Tuesday morning on the west side of the line, it’s still Monday morning on the east side of it.

Until last year, Samoa and American Samoa celebrated the new year on the same day. But then Samoa hopped west of the line so it could trade more easily with countries such as Australia and New Zealand.

Because the date line is not fixed by any international law or agreement, it can zig and zag to accommodate such government and business interests.

American Samoa, however, stayed on the other side of the border – leaving it 25 hours behind Samoa.

Samoa isn’t the only place the international date line bends (quite literally) its rules for.

Take the tiny Pacific Island nation of Kiribati.

Before the mid-1990s, the international date line split Kiribati into two parts, leaving the western portion a whole day ahead of the eastern part and causing headaches when doing business.

Now, the date line takes a massive detour of more than 2,400 kilometers (1,500 miles), around Kiribati’s eastern-most islands, so that the whole nation is on the same calendar day.

Near the top of the globe, the date line veers east to get all of Siberia on board with the rest of Russia.

It then swings far west to lasso in the Aleutian Islands, so they can to be on the same day as the rest of Alaska.

This means some Russians will see 2013 a full day before some Americans.

Perhaps they can tell their neighbors on the other side of the squiggly line what the future holds.

CNN’s Ric Ward contributed to this report.