Wrapping your head around a trillion $$$$

How much money is a trillion dollars• At the moment, the government seems to be throwing around money in trillion-dollar chunks, so it's a pertinent question. But "trillion" is such a huge number. It's really hard to grasp a number that big. So how do you get your arms around it?

Some people have tried to express it in terms of size. For example the average $1 bill is a tenth of a millimeter thick. It takes approximately 250 bills to equal an inch. Therefore, if you were to stack a trillion $1 bills on top of each other, the stack would be about 4 billion inches tall. Which works out to something around 65,000 miles. That's roughly a quarter of the way to the moon.

Which is nice to know, but it doesn't really tell you that much. Not many people have been to the moon. To really understand a trillion dollars, you need to compare it to something that's easier to understand.

For example, if you assume the average cost of a new car is $20,000, then a trillion dollars is 50 million new cars. If you consider that there's roughly 100 million households in the United States, it means that the government could buy every other household a new car.

If you assume that the average worker earns about $40,000 per year in the United States, it means that the government could employ 25 million people for one year with a trillion dollars. Or it could employ 12.5 million people for two years. Coincidentally, there were a total of 12.5 million unemployed people in February of 2009. So the government could employ every unemployed person in the country with a $40,000 job for two years with a trillion dollars.

If you assume the average price of a house in the United States is $200,000, then a trillion dollars is five million houses. That means that the government could spend a trillion dollars and buy all of the houses foreclosed on in 2007 and 2008, plus some part of 2009. If the government had a way to sit on those houses for a couple years and then sell them off when the housing market improves, there is some possibility it would get a portion of that trillion dollars back.

If you assume that there are 300 million men, women and children living in the United States, then a trillion dollars is $3,333 per person. The government could simply write a check to everyone. The typical family of four would receive $13,332 to spend as it chooses. That kind of money might have a big effect on the economy.

If you assume that it costs $10 billion for a mission to Mars -- a mission that puts several human beings on Martian soil and brings them back -- then a trillion dollars is 100 missions to Mars. That's not accounting for any efficiencies of scale. We could probably start a whole Mars colony and put several hundred people in that colony with a trillion dollars.

Or here's another way to think about it. If you assume it costs $10 million to build a mile of Interstate Highway in the United States, and if you assume that the current Interstate Highway system contains 50,000 miles of highway all over the United States, then a trillion dollars is enough to build two complete copies of the entire Interstate Highway system that we have today.

If you assume that an acre of rural farmland in the U.S. costs $3,000, then a trillion dollars is enough money to buy 300 million acres of farmland. The state of Kansas is 52 million acres, so a trillion dollars would let you buy all the farmland in the state of Kansas six times over. In other words, you could buy all of the farmland in Kansas, Nebraska, Iowa, Wisconsin, Illinois and Missouri. Take a look at a map of the United States -- that's a lot of land.

If you assume that the Amazon rain forest is about as big as the continental United States, it occupies 3 million square miles or so. That's two billion acres of forest. If you assume that an acre costs $100, a trillion dollars represents five entire Amazon rain forests. If you assume it costs $50 per acre, it is 10 entire Amazon rain forests. The government could buy and protect approximately every rain forest on the planet with a trillion dollars.

If you assume that the war in Iraq has so far cost $650 billion, then a trillion dollars is one and a half wars in Iraq.

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