Most genies would have done the obvious thing, which is to crush you under the weight of a pile of fifty-rial coins worth a total of about four hundred bucks and only valid in Iran. But you were lucky enough to get a more reasonable genie, who’s going to try to give you what you wanted and not just what you asked for. He gives you the choice of what currency you want it in, assures you it won’t be stolen from any nearby easily-angered shopkeepers or otherwise illegal, and definitely doesn’t put it directly above your head. He even makes it a metric ton, because he’s a reasonably nice genie and that’s a) more money for you and b) easier numbers for me.
Other genies would have granted your wish to the letter, and given you the famous one-ton coin. It’s Australian legal tender (made in the mint at Perth) and is worth precisely one million Australian dollars. You can’t very well spend it, and it’s probably illegal to destroy it to get at the forty million dollars worth of gold it’s made of (apparently someone thought making a $1M coin out of $40M worth of gold was a good idea). So someone would find out you had it and you’d either get charged with being the world’s best thief or the worst.
The best currency to ask for, in terms of value per gram, is the Latvian lat. One lat is worth $1.89 in U.S. money, and unlike most high-valued currencies it comes in high denominations, up to 500.
Modern banknotes are made of cotton paper, which has a density of about 85 g/m^2. Latvian bills are 130mm x 65mm, so they weigh .71 grams per banknote. Since each is worth $943 and you’ve got one million grams of them, you’re rich. You are now the proud owner of a one-ton stack of valuable currency worth a little under $1.33 billion, and rich beyond the wildest dreams of any rodent ever. Satisfied with a job well done, the genie vanishes in a puff of smoke. Your money becomes obsolete when Latvia switches to the euro on January 1 2014.
You don’t want to have to deal with that, so you stick to currencies you’re more familiar with and ask for it in US dollars. The Omani rial (not to be confused with the Iranian rial) is worth a lot more per gram, but at least you have more information about the dollar. (If that doesn’t apply to you, go for the more valuable currency.) One ton of US hundred dollar bills is 1000000g/(.157m*.066m*85g/m^2)=1.13 million bills, or 113 million dollars. That’s disappointing. It’s probably a life-changingly big number, but isn’t world-changingly big. You can’t wreck Earth’s economy by accident, or build a space elevator on purpose, or do anything on a really big scale.
So what if, instead of asking for “a ton of money,” you use some other expression?
Maybe you just ask for a lot of money. You don’t think you were being very specific, but taking things unnecessarily literally is kind of what I do here. So the first thing to do is find the area of a typical parking lot. (Why a parking lot instead of some other kind of lot? Because why not.)
A small strip mall is about 5000 square feet. A typical city’s code* says 1 space per 300 square feet of retail area, and one space takes up about 150 square feet. So there are 2500 square feet in a typical parking lot. In more sensible units, 232.2576 square meters. Since a dollar bill is .157m x .066m=0.012m^2, one bill takes up one 22,414th of the parking lot area. If you’re going to fill the parking lot, one layer probably isn’t enough. Hundred dollar bills are shipped in stacks of one hundred, so let’s make it one layer of stacks. The contents of this lot are worth a little over 224 million dollars. That’s more than twice as good as a mere ton of cash, but it’s still the same order of magnitude.
What if we tried more?
The value of a boatload of money would, obviously, depend on the boat. A rowboat can hold about 290 kg before it sinks, so you’d be three or four times better off asking for the ton. But since this particular genie wouldn’t pick a small boat, let’s say it’s enough legal tender to sink the Titanic.
The Titanic has a deadweight of 13,550 tons. Since units of measurement have a long and confusing history, those are neither U.S. tons nor metric tons, but British long tons. Which is 2240 lbs or 1016 kg, so the Titanic could hold an absolute maximum of 13,767,477.5 kilograms of money. Now we’re talking. It’s about 13,800 times the one-ton estimate. $1.563×10^12.
You’re the richest person on earth, with over one and a half trillion dollars. You can afford to purchase enough solar panels to cover an entire degree of Earth’s surface, then buy Manhattan or Florida but not both. And maybe build a few space elevators with the change. And now, the number actually is big enough to affect the money supply just by existing.
There is a total of about $10.3 trillion of US money in existence. That counts all the cash, plus checking and saving accounts and money market funds, certificates of deposit, and things like that that I only know about because I Googled it. The genie increased the US money supply by over ten percent. So you just caused enough inflation to significantly lower the value of the dollar. And it’s even worse than that. In terms of actual cash, as in coins and bills, there’s only about four trillion US dollars. That’s the total across all currencies. You suddenly more than tripled it. I don’t know what effect that has, but I doubt it’s good. The genie knows even less economics than I do, or he would have chosen to interpret the wish differently.
Hey, this didn’t even kill everyone! For a hypothetical question, it was pretty successful.
*Typical=showed up on Google