Today, we try to make sense of the International
Date Line. The University of Houston's College of
Engineering presents this series about the machines
that make our civilization run, and the people
whose ingenuity created them.
voyage went west in 1519. His ships crossed the
Atlantic, Pacific, and Indian Oceans, came around
Cape Horn, and finally landed in West Africa, where
Portuguese locals told the surviving captain that
it was Wednesday. That didn't make sense. He'd kept
careful track of the time. He knew it was Thursday.
That was the first time anyone had faced the date
line problem. It was a drama that would play many
times through the 16th century. As settlers moved
east and west, they met -- usually in the Pacific
-- and there they disagreed on the date.
The date change soon mutated from mystery and
surprise into annoyance. By the 19th century,
settlers who'd gone west carried their time as far
the Philippines. But Guam and New Zealand are far
this side of the Philippines. They were settled by
Dutch who'd sailed east. So it was Tuesday in the
central Pacific while it was still Monday out in
So the Pacific people had to struggle with American
time and Asiatic time. All Europe wanted was to
keep the date change out of sight. If the Greenwich
meridian went through London (the center of their
universe), the most remote place on Earth was the
180th meridian. That was clearly the place to reset
But the central Pacific isn't empty. A hundred
vested interests sent the line zigging here and
zagging there. The king of Samoa, under pressure to
adopt "American" time, said: "Look, if we use
Asiatic time, then America will observe the Fourth
of July two days in a row."
Finally, an 1884 conference created an
International Date Line. Alaska had been on Asian
time when it belonged to Russia. The International
Date Line still doglegs far east to pass through
the Bering Straits. That keeps all of Russia on
Asian time. Then the line lurches west to keep the
Aleutians on American time. When it's Tuesday in
Japan and at the tip of Siberia, it's still Monday
in western Alaska. The problem is, much of Siberia
lies far this side of Western Alaska.
The line doglegs east a second time to keep Tonga,
Fiji, and New Zealand on Asian time. Today, Tonga
and Samoa -- next-door neighbors -- have to run on
different time. Protestants who keep a strict
Sabbath settled both island groups. Both now
restrict travel on Sunday, but Sunday occurs twice
in a row. The result? Regional travel grinds to a
halt two days out of seven.
The date line seems simple enough. Yet it leads us
into subtle confusions. The problems it poses keep
coming back -- both to tease us and to surprise us.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds