It was nighttime. I was flying on an airplane. As we were landing we passed over a highway. I saw cars below with their headlights on. I could see that the light from their headlights only lit up a certain distance in front of them. Any object that fell past that distance would have probably looked dark to the driver.
I'm confused as to how I was able to see this thousands of feet up in an airplane. The light from the cars' headlights only traveled a few feet in front of the cars but also traveled thousands of feet to the airplane I was on? How is this possible?
Also, how could I see the beam-light structure of the light, if the light is able to be seen by an observer in any direction? I feel like none of this makes any sense and we were never taught anything to clarify this in E&M. Maybe I just missed something truly important.