About Alaska?

Alaska is a big state. You only get almost 24 hours of light or darkness north of the Brooks range. At the other extreme, on Kodiak Island, it was light at about 2 AM during the summer. Nice, except that those of us on salmon migration watch had to be awake then and be up in the counting tower. When we finished, we could clean up and start a pot of coffee for the lucky ones who could sleep late.

In Barrow, Alaska, the sun sets on November 18 or 19, and it remains below the horizon for about 66 days. This creates a polar night that lasts until the Sun returns to lightly touch the horizon (due to the refraction and scattering of the atmosphere) by January 22 or January 23. The sun then rises again completely over the horizon by January 27 or 28. During the first half of the polar night, there is a decreasing amount of twilight each day, and on the winter solstice (around December 21 or December 22), civil twilight in Utqiaġvik lasts for a mere 3 hours.

1. Yes, and north of the Arctic Circle, it's daylight 24 hours in the summer. The further north you go, the longer the sun stays up until you reach the Arctic Circle, after which point it stays up 24 hours, the sun never rising or setting but traveling in a giant circle all the way around the Earth's horizon in the summer.

2. In the winter, it stays as dark for as long as it stays light for in the summertime. It's like that everywhere on Earth-- the length of a given day being exactly equal to the length of a night exactly 6 months before or after that given day and vice versa.

3. On the spring and fall equinox, so March 21 and September 21, a day and night are exactly 12 hours everywhere on Earth, whether at the North Pole, the South Pole, the Equator, or in Alaska.