Recently, Nick Paumgarten in the New Yorker had someone explain that if you represented the national debt as a basketball, that then the average American's income would be, in comparison, impossible to see with any microscope, no matter how powerful. Not entirely so, claims a physics dude in this week's letters to the editor! This physics dude, using an average income of $91K a year, cough, says that "the size of a grain representing the income of $91,000 is 1/493 the diameter of a nine-inch basketball, or about half a millimetre." See the above to-scale graphic, and be... reassured? Intrigued? Horrified?