# The Naked Scientists Forum

### Author Topic: More possible chess moves than atoms in the observable universe?  (Read 18587 times)

#### majorminor

• Jr. Member
• Posts: 46
##### More possible chess moves than atoms in the observable universe?
« on: 22/04/2013 12:12:53 »
I have been playing chess online  for over 10 years now and heard about this statistic a long time ago and assumed it was just some sort of joke. That there are more possible chess games or continuations than atoms in our observable universe!! Many years later Garry Kasparov (one of the greatest players ever) mentioned this fact !? in a TV interview and so of course I googled, and it  appears to be statistically consistent. I can understand its a statistical thing made possible by many repeating moves and situations but still it does not sit right with me and I am hoping it is refuted somehow in the future. To think of the amount of atoms in a grain of sand then to think of the amount of atoms in the universe .... surely somebody did not carry the 1 in their calculations. Maybe its all above board but I do not like it!

#### damocles

• Hero Member
• Posts: 756
• Thanked: 1 times
##### Re: More possible chess moves than atoms in the observable universe?
« Reply #1 on: 27/04/2013 04:54:50 »
Let us try a quick back-of-envelope estimation:

The number of chess games possible might be around 50 moves a side times 20 options per move, making 20^100 different games.

The number of atoms in the observable universe might be around 10^25 per kilogram times 2 * 10^30 kg per solar system times 10^14 stars per galaxy times 10^14 galaxies in the observable universe.

Comparing the very large numbers, 10^83 is clearly less than 20^100, so the conjecture is probably true.

#### RD

• Neilep Level Member
• Posts: 8131
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##### Re: More possible chess moves than atoms in the observable universe?
« Reply #2 on: 28/04/2013 00:38:46 »

#### majorminor

• Jr. Member
• Posts: 46
##### Re: More possible chess moves than atoms in the observable universe?
« Reply #3 on: 02/05/2013 22:03:47 »
Maybe the universe is smaller than I have always imagined or I cannot properly imagine the enormous numbers involved.
All those possible chess moves and still I let my horsey get  eaten for free :))))
And music too with its astronomical variations and still I  cant sing.  But its a wonderful world.

#### The Naked Scientists Forum

##### Re: More possible chess moves than atoms in the observable universe?
« Reply #3 on: 02/05/2013 22:03:47 »