To the Editor:

It occurred to me, reading Joseph Sawyer's letter on the national debt ceiling (Sept. 14), that I didn't know what $1 trillion is, let alone $2 trillion. Of course, I knew that a trillion is a thousand billion and that a billion is a thousand million. But I didn't really understand what that means. Knowing there are 12 zeros in a trillion didn't help much either.

Why not think of it in terms of seconds, I asked myself? A trillion seconds would have to be years, probably many years ago. I made a wild guess. As it turned out, I wasn't close. I found that 1,000 seconds ago was equal to almost 17 minutes. It would take almost 12 days for a million seconds to elapse and 31.7 years for a billion seconds. Therefore, a trillion seconds would amount to no less than 31,709.8 years.

A trillion seconds ago, there was no written history. The pyramids had not yet been built. It would be 10,000 years before the cave paintings in France were begun, and saber-toothed tigers were still prowling the planet.

I was stunned. At first I thought I must have made a mistake, but a banker friend checked my figures and pronounced them accurate.