Air Date: Week of December 20, 2002

This week, we have facts about polar night. Contrary to popular belief, most Arctic communities experience polar twilight, not absolute darkness, for the winter.

Transcript

CURWOOD: Welcome back to Living on Earth. I'm Steve Curwood.

[MUSIC: Wimme, “Boiling Spring”, WIMME (Rockadillo, 1995)]

CURWOOD: With the winter solstice upon us, you may start feeling sorry for folks who live above the Arctic Circle. In the far north, people encounter the true polar night, which is a 24 hour period of no sun, to experience this deepest winter darkness at about 400 miles above the Arctic Circle on the shortest day of the year, the winter solstice.

But communities above the Arctic Circle still do get a bit of winter sun. Even when there is no direct sunlight, the atmosphere bounces the sun's rays around the curve of the earth. This reflected light creates a surprisingly bright polar twilight, enough to read by for at least a couple of hours each night.

And if you head north this time of year, don't be surprised to find yourself yearning for the sun. Some people can't sleep without the sun setting their internal clocks while others start to hibernate.

Thoroughly modern folks at the high latitudes have found a way around this problem. Many turn on daylight spectrum lamps for a daily dose of sunshine. Of course, there is another more pricey cure for the seasonally affected: hop a plane to the tropics.

And for this week, that's the Living on Earth Almanac.

[MUSIC FADES]