From:http://en.wikipedia.org/wiki/Planck_length

In physics, the Planck length, denoted P, is a unit of length, equal to 1.616199(97)×10−35 metres. It is a base unit in the system of Planck units. The Planck length can be defined from three fundamental physical constants: the speed of light in a vacuum, Quantum gravity and minimum length

网页资源:Higher-Dimensional Algebra and Planck-Scale Physics –BY John C. Baez            <——————————–|

                                This paper has a followup: Quantum Quandaries:A Category-Theoretic Perspective                                |

                                                     This paper is a followup to Higher-Dimensional Algebra and Planck-Scale Physics.  >——|

Physics Reerence Data上的 http://physics.nist.gov/cgi-bin/cuu/Value?plkl (普朗克长度常量)