It's amazing how the earth works, just like we know, the rotation of the earth about its axis cause day and night, the day when a part faces the sun and night when not getting the rays of the sun, but during rotation the earth also undergo a tilt of its axis of about 23.5° and this tilt explains day and night varation in the Arctic.
And still there are people out there that seriously believes the earth is flat! I cannot phantom how it's possible. The shipping industry has been counting on the fact that the earth is round for centuries. Yesterday we had a guided tour at the Observatory in Oslo. It's primary purpose was to aid the shipping in positional services (finding the exact coordinates for Oslo, broadcasting time signals to the harbour allowing captains to calibrate their timepieces, calibrating sextants).
I wonder why they still belive that, although that might be with regards to their experience staying in the Arctic, but Geography had made it clear on that, now we have pictures taken of the earth from space, explanation on day and night and more to prove the earth's shape.