Editor's Note: Vienna, Austria-based science writer Chelsea Wald is taking part in a two-week Marine Biological Laboratory journalism fellowship at Toolik Field Station, an environmental research post inside the Arctic circle. To see the current conditions in Toolik, check out the Webcam.

I packed my flashlight. That's really stupid. I'm above the Arctic Circle near summer solstice. The sun never sets. Never. It's like when my friend packed her umbrella to go to the Sahara.

Why doesn't the sun set? Check out this diagram (from The National Weather Service and NOAA). As you can see, the Earth's axis tilts. In the northern hemisphere summer, about the time of the solstice, the North Pole tilts toward the sun. As the Earth rotates over the course of a day, there's a small section around the North Pole that's always in the sun and never in the shade. That's the Arctic Circle. The sun never gets terribly high in the sky, but it also never sets.

Some people have a hard time sleeping in 24-hour sun. My first few days in Alaska I often woke in a panic, thinking that I had overslept my alarm. A study of a summer expedition to the Antarctic in the early 1990s found that two out of three participants slept poorly. "These problems can mostly be attributed to disruption of circadian rhythms, ‚a cold exposure, and psychosocial stress," wrote the authors of a 2008 Lancet review article on the psychological effects of polar expeditions. There's even a certain number of Arctic dwellers who get a summer version of Seasonal Affective Disorder; they get depressed in the summer instead of the winter.

However, most people here at Toolik Field Station say that the main problem is that it's easy to forget to go to sleep. Even if the clock says that it's 11 pm, "I don't believe that it's 11 pm," Louisa Jonas, a Baltimore, Md.-based radio producer also on the fellowship program, told me. "It's just like 6 o'clock at night for a really long time."

For the scientists working here, that can be trouble. "You don't have any clues as to when you have to stop working," said Kevin Griffin, a plant ecophysiologist from Columbia University who has been at Toolik a few weeks already. He worries about his students getting burnt out from working too long. That could become a problem for me, too. Right now it's midnight, and I'm wondering whether I'll work through the night.

Of course, sometimes it's useful to work through the night. This field season, Griffin's team will test Arctic plants every two hours for the entire 24-hour cycle in order to study how they cope with the 24-hour sunlight. Of course, more sunlight means more photosynthesis, but plants also need respiration, which for lower-latitude plants largely happens when photosynthesis turns off at night. Without that nighttime break, Griffin said, Arctic plant leaves' respiration is sure to be "very different from what an oak leaf does in New York."

Today is the summer solstice. Most people love this longest day of the year. But what if the day never ended? Would you love that, too? I'm certainly enjoying the 24-hour sun for now, but when I leave I'm pretty sure I will embrace the night like an old friend.

Image credit: Illustration of Earth's tilt, equinoxes, solstices and seasons, courtesy of NOAA and the National Weather Service