 Young eventually concluded that “After The Gold Rush is an environmental song...I recognize in it now this thread that goes through a lotta my songs that’s this time-travel thing...When I look out the window, the first thing that comes to my mind is the way this place looked a hundred years ago.” 

"After the Gold Rush" consists of three verses which move forward in time from the past (a medieval celebration), to the present (the singer lying in a burned out basement), and, finally, to the end of humanity's time on Earth (the ascension process in which the "chosen ones" are evacuated from Earth in silver spaceships).