Universal constants

In physics, a physical constant is a physical quantity that is generally believed to be both universal in nature and constant in time. It can be contrasted with a mathematical constant, which is a fixed numerical value but does not directly involve any physical measurement.There are many physical constants in science, some of the most widely recognized being the rationalized Planck's constant h, the gravitational constant G, the speed of light in the vacuum c, the electric constant ε0, and the elementary charge e. Physical constants can take many dimensional forms: the speed of light signifies a maximum speed limit of the universe and is expressed dimensionally as length divided by time; while the fine-structure constant α, which characterizes the strength of the electromagnetic interaction, is dimensionless.
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There are a limited number of physical constants that are the same throughout the universe and unchanged since the beginning of time and will be the same forever. In as sense this is an act of faith by physicists, but as more and more sophisticated experiments are conduced the truth of this becomes more compelling. Science in general would be in considerable trouble if the laws of nature where slowly changing. The short list contains the speed of light , rest mass of the electron, etc. but not Man developed mathematical quantities such as pi (= 3.1415, the ratio of the number of times the diameter of a circle goes into its circumference).