When talking about large numbers - national debt, cost of the Iraq war, economic bailouts, or just the distance to stars we have to use some very large numbers. Unless the numbers are shortened a bit to a more readable format, the decimal point is just so far to the right of the long line of numbers that it's just totally pointless.
So, astronomers and other scientists like to abbreviate numbers using scientific notation, avagadro's number or mole, light year, parsec or simply 1 mile is the same as 5,280 feet.
We wouldn't want to write out light years in feet, since that would be:
1 Light Year = 3.10383858E+16 Feet -- to hard to write, so we use light years for distances to the stars....etc.
Anyway, the point of this blog entry is leading to a site that I came across that shows large numbers in an interesting format. It shows how large numbers of pennies would look. An interesting way to get a clue about how big numbers would look if shown as something familiar.