How Random is a Deck of Cards?

A Humble Deck of Cards

Here is a short post about a humble deck of cards. Statistically speaking, after 7 riffle shuffles (below) of a deck of cards, a deck of cards is appropriately shuffled, meaning that the deck could now be in any one of 10⁶⁸ possible arrangements.

Image: Johnny Blood

To put that number in perspective. If there were a quadrillion galaxies (10¹⁵), each galaxy with a trillion suns (10¹²), each sun with a trillion planets (10¹²), each planet with a trillion inhabitants (10¹²), and each inhabitant shuffled a deck of cards every second, and had been doing this since the beginning of the universe (10¹⁷), we would only now be expecting to be getting repeats.

Every shuffled deck of cards, to an extraordinary significance can be said to be truly unique, that is no deck of cards has ever been in that order before, nor will any ever be in that order again.

Except the order that new decks come in. That happens all the time.

Cheers,

     - Scott