Sometimes scientific units are not quite of the right magnitude, so scientists pile them up, using standard prefixes to indicate the size of the pile. As shown in the table below, kilo-indicates a thousand somethings, which means that a kilogram is a thousand grams and a kilometer is a thousand meters, and so forth. This table provides pre-names for thirty-six orders of magnitude (where one order is ten times something), from exa-to atto-, to wow your friends, impress your mom, and more importantly, to speak cogently about the huge numbers of joules, watts, MacKays, and dollars that drive the US economy.
Note: The US national debt on June 30, 2012 was $15,856,367,214,324.44 or approximately 15.9 petadollars (PUSD) according to the US Treasury website (www.treasurydirect.gov/NP/NPGateway).