Imagine if two people got in their cars and drove to work. They both live in different places and work in different places. They live miles from where they work. Their driving paths cross at one point.
There are no other cars in the universe, just these two (remember, I'm asking you to use your imagination). And from the first time they make the commute to work and back thereafter, the cars make the same trip every day on autopilot.
Eventually, this might happen:
According to Sorting Out Science (whence I totally stole this video) this is a reconstruction of a collision between two communicatoins satellites over Siberia. Think of all those people at that very moment looking at their cell phones and going "Hmmmm... must be in a dead spot....."