why does it get dark sooner in nyc?

Our Answer:
Because we are up north.

THE Answer:
The earth it tilted 23.5 degrees in relation to the plane of the orbit around the sun. Because of that, we get seasons and right now, the sun is almost perpendicular over the Capricorn tropic, which is in the southern hemisphere.

Here, up north, the sun is much lower over the horizon and it gets up later and sets sooner. In the north of my country, Norway, the sun doesn't rise at all in December. It happens anywhere at the north of the polar circle.