Posted in Science & Nature

# Card Shuffling

Take a standard deck of playing cards. Shuffle it thoroughly and set it on the table. Consider this: what is the probability that the order those 52 cards are in is the same as the order of a deck shuffled by someone else? The answer can be found using a simple maths equation: 52!

! denotes a factorial, where you multiply the number to every other positive integer smaller than it. For example, 5! = 5 x 4 x 3 x 2 x 1 = 120. Due to its nature, factorials grow rapidly – even faster than exponentials. For example, 10! is 3.6 million and 15! is 1.3 quadrillion. By 52!, the number grows to:

80,658,175,170,943,878,571,660,636,856,403,766,975,289,505,440,883,277,824,000,000,000,000.

This number is so big that if every star in our galaxy had a trillion planets, each with a trillion people living on it, all shuffling a trillion deck of cards at the rate of 1000 shuffles per second, since the beginning of time, only now would someone have a deck that is in the exact order as your deck.

Ergo, you can say with absolute, mathematical certainty, that the deck you have shuffled is in an order never created by any human being in the history of the world.  