Computational capacity of the universe.
All physical systems register and process information. The laws of physics determine the amount of information that a physical system can register (number of bits) and the number of elementary logic operations that a system can perform (number of ops). The Universe is a physical system. The amount of information that the Universe can register and the number of elementary operations that it can have performed over its history are calculated. The Universe can have performed 10(120) ops on 10(90) bits ( 10(120) bits including gravitational degrees of freedom).
Lloyd
Seth
S
d'Arbeloff Laboratory for Information Systems and Technology, MIT Department of Mechanical Engineering, MIT 3-160, Cambridge, Massachusetts 02139, USA. slloyd@mit.edu