Answer:
I am a path between high natural masses; remove the first letter to get a path between man-made masses.
What goes up and down, but does not move?
I have an eye, but I can't see. I usually have to work with something in my eye. What am I?
What loses its head in the morning but gets it back at night?
Sometimes I fly as fast as the speed of light. Sometime I crawl as slow as a snail. Unknown until I am measured but you will certainly miss me when Iām gone.
It's what light turns into in the night