FYI: The size of a bit of entropy

[Michael_Heyman at NAI.com]

I find it interesting that we actually know the size of a bit ;-)

From:
<http://www.sciam.com/article.cfm?articleID=000D6E85-2E76-1F0C-97AE80A84
189EEDF>:

  Planck area, approximately 10^(-66) square centimeter, 
  is the fundamental quantum unit of area determined by 
  the strength of gravity, the speed of light and the 
  size of quanta...it is as if the entropy were written 
  on the event horizon, with each bit (each digital 1 or 
  0) corresponding to four Planck areas.

I read this as the entire AES256 lookup-table (plaintext/ciphertext pair
and matching 256 bit key) only takes about 2400 square kilometers
(assuming I did my arithmetic correctly). The Larsen B ice shelf lost
this much area between 1998 and 2000. Dang, we could have used that.

The full article at:
<http://www.sciam.com/article.cfm?colID=1&articleID=000AF072-4891-1F0A-9
7AE80A84189EEDF>

has discussions on maximum information capacity in the physical world.

-Michael Heyman

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