UUIDs are really fantastic. They provide a seemingly endless supply of unique values that you can be used to tag items, identify database records, and much more.

A uuid is basically a 128-bit number. It is hard to express how many possible UUIDs there can be, but let me try nonetheless.

Imagine that the US Treasury printed a one dollar bill imprinted with a unique uuid starting at the lowest value, 00000000-0000-0000-0000-000000000000, and working sequentially up to the highest value, ffffffff-ffff-ffff-ffff-ffffffffffff. Ignoring the fact that this would take longer to complete than the universe is old, lets move along.

Current estimates are that the universe contains something on the order of 10^21 stars, i.e. 1,000,000,000,000,000,000,000 stars. Now lets imagine that each star has one planet orbiting it that is inhabited (bare with me, it's just a mental exercise). Assume that there are the same number of individuals living on each of these planets as on earth, 6 billion individuals. This gives us a population of 6 x 10^30 or 6,000,000,000,000,000,000,000,000,000,000 people.

Finally, let's take that stack of one dollar bills and divide it evenly amongst all those individuals. How much money would each one have?

If you did this each person in this made up universe would end up with $56,713,727.