....

An example of the idea of relativity is when you're seated in a train and notice that the train next to yours begins to move. It's quite disorienting. Is it moving or are you? You don't know until you see a third reference point, like the platform. That's relative motion.

In a similar way, time is relative. But there is no ultimate platform. We don't notice the differences because they are infinitely small. Time seems nonexistent when you're awake in the middle of the night because you lack a reference to where you are in it. There's no backdrop -- people coming and going, variations in the sunlight outside -- against which to gauge it.

I often refer to John Boslough's recollection of graffiti that he observed on a cafe wall in Texas:

"Time is Nature's way of keeping everything from happening all at once"

In his article, "The Enigma of Time" (National Geographic, March 1990)," he reminds us that children before the age of two have little sense of the passage of time and that it may have been the same for our early ancestors. Some scholars believe that people once lived in a state of "timeless present" with little or no sense of past or future.

He mentions an old Hopi Indian woman in northern Arizona, who talks of a close friend, dead for several years, as if he just stepped out the door. Hopi verbs make no distinction between past and present. All time runs together, something like an ever-continuing present. Clocks and calendars suport the illusion that we live in a world of mathematically mesured segments of time. But physical time is relative. It depends on things that happen -- how we perceive them to be happening -- in our outer world. Tims is not happening to us.

....

[End of excerpt]