If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?: Seventy-Five Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life

by Stephen Webb

The Bekenstein Bound Jacob Bekenstein showed how quantum physics places a limit to the amount of information a physical system can code. The uncertainty relations show that the amount of information inside a system of radius (in meters) and mass (in kilograms) can never be greater than the mass multiplied by the radius multiplied by a constant (which has a value of about bits per meter per kilogram). Nature permits a surprising amount of information to be encoded before the Bekenstein bound is reached. For example, a hydrogen atom can encode about 1 Mb of information. A typical human can code about Mb of information—far more information than can be handled by any hard disk in existence. Natural physical systems seem to encode much less information than Nature permits. But the Bekenstein bound gives planetarium designers plenty of opportunity to engineer perfect simulations of varying size and scope. Standard thermodynamic calculations give us the energy required to construct a perfect simulation of any particular size and mass.