Lots of zeros

Large numbers fascinate me. I think this started as a child with my interests in dinosaurs (millions of years ago), the speed of light (unbelievably fast), and the distances in the universe (one light year is nearly six trillion miles). It continues today, but now the context is often something like the federal budget deficit or the cost of waging war.

Here is how I make sense of large numbers. First, consider the ordinary paper clip, which weighs about 1.4 grams. One million paper clips weigh nearly 3,100 pounds, or over a ton and a half. The number "one million" is very large when you envision a ton and a half of paper clips in your office. But the number "one billion" is much larger; one billion paper clips weigh more than eight Boeing 747 passenger jets. And the number "one trillion" is almost too large to fathom. This many paper clips would weigh more than four Empire State Buildings.

Next, consider a penny, which is 1.55 millimeters thick. A stack of a million pennies would reach nearly a mile high. A billion pennies would reach from Des Moines along Interstate 80 a little ways past the Utah-Wyoming border; driving at freeway speed (75 miles per hour) it would take almost thirteen hours to drive that distance. And a trillion pennies would reach around the earth nearly 39 times or between the moon and the earth four times. And I don't think I can drive that far.

Finally, consider time. There are 86,400 seconds in a day. This is a number I can grasp. One million seconds is just over 11.5 days, or a week and a half. So each month sees the passing of almost three million seconds. But a billion seconds is almost 32 years. With luck, I might reach the ripe old age of three billion seconds. But I'll never reach one trillion seconds; this is nearly 32,000 years.

So I get a little concerned when I hear that the federal deficit has reached the trillions of dollars. From the US National Debt Clock:

The Outstanding Public Debt as of September 19, 2008 is $9.7 trillion. The estimated population of the United States is 304 million, so each citizen's share of this debt is nearly $32 thousand.