A Beam of Light

My wife and I went to visit a church with friends today.  It was one of those new, "hip" churches where the auditorium looked like a miniature concert arena complete with dramatic lighting and stadium-style seating (they did indeed kick out the Jesus-jams, so to speak) , and the minister wore blue jeans and a goatee.  As he spoke, I began to notice the spotlights on the ceiling pointing towards the stage.  The ceiling and tops of the walls were jet black and completely unlit (save for the spotlights shining on the stage), but  the walls became lighter in color as they approached the floor.  It made me think of Idea #2 from the class discussion  . . . "The hallway (or box) wasn’t dark enough to allow us to see the beam. Some said that a darker room would allow us to see the path of light, because there would be more contrast."  Coming out of the spotlight on the ceiling, one could clearly make out the beam of light coming from it.  However, as the walls became lighter, the beam of light seemed to disappear, and one could clearly see the area of the stage where the light came to a stop.  So I decided that after the service I would walk around and try to view the light from different vantage points.  As my perspective changed, so too did the length of the beam of light that was observable (which harkens back to Idea #4 which said, "Some said that whether you see the path of light, the source of light, or just lit areas depends on where you are standing and looking.").  How much of the beam was visible seemed to depend on how dark, or light, the area surrounding the light was.  In my mind, this rules out Idea #5 which states, "The path of light is only visible when it hits something in the air (like moisture, smoke, or dust).  The auditorium was not smoky or dusty (or moist for that matter).  It was simply darker towards the ceiling.  I could see how this could also prove Idea #1, because the light was much brighter than your average, every day flashlight.  It also lends credence to Idea #3 which states, "A more open space would allow us to see the path of light, because there wouldn’t be any reflections to interfere with the beam."  So the only clear answer I was able to surmise is that Idea #5 is the only idea that does not fit.