Perspective

Astronomer Carl Sagan devised an ingenious illustration. He called it his "Cosmic Calendar." And it not only enlightens, but provides an object lesson in humility. Here's how it works ...

Imagine that the 13.7 billion-year history of the universe is compressed into one calendar year. The Big Bang occurred in the very first second of January 1 and the current moment is the last second of the last minute of December 31. Using this compressed timescale, each month equals a little over one and quarter billion years. Each day represents 40 million years. Each second covers 500 years of history.

The Milky Way coalesces in March. The sun and planets form in August. The first life - single celled - show up in September, the first multi-cellular organisms in November. The first vertebrates appear on December 17. Dinosaurs show up on Christmas Eve. (And become extinct on December 29.) Modern humans finally appear at 11:54 p.m. on December 31. And all of recorded history occupies the last ten seconds of the last minute of the last day of the year. The pyramids were built nine seconds ago. The Roman Empire fell three seconds ago. Columbus discovered America one second ago.

Talk about putting things in perspective...