Sunlight and Darkness: The extremes of sunlight and darkness change rapidly in polar environments. Because the earth is tilted on its axis and the earth takes approximately 365 days to fully orbit around the sun, sometimes polar regions are in full sun or darkness. Depending on where you live, you might have noticed that the sun sets later in the evening during the summer season, while the sun sets earlier during the winter. The closer you live to the equator, the less you’ll notice changes in sunset times over the year.
On our polar expedition, we just missed 24-hour daylight by a few days–this is when the sun doesn’t even set! On the first day of our expedition, sunrise was at 1:59 a.m. and sunset was at 11:55 p.m. That’s 21 hours and 56 minutes of daylight! Even when the sun dipped below the horizon, it didn’t get fully dark. On the last day of our expedition, sunrise was at 8:26 a.m. and sunset was at 5:04 p.m. That’s 8 hours and 39 minutes of daylight. During just two months, the amount of daylight decreased by 13 hours and 17 minutes. Wow!
There are two more things that make this environment unique. They don't neccesarily help people live here (and they sometimes make it more challenging to live here!), but they certainly make this enviornment special.
Icebergs: Greenland is almost fully covered by an ice sheet that is up to 3 kilometers (2 miles) thick. As we have learned in previous weeks, the Ice Sheet is being pulled downward toward the ocean by gravity, and the large sections of ice that calve off at the edge are called icebergs.
