Planck length
The Planck length () is an extremely small unit of length. It is calculated from three physical constants: the speed of light, the Planck  constant, and the gravitational constant. The length was established as a way to simplify many of the more fundamental equations — if you write down equations in Planck units, you can do away with many physical constants and not have to worry about dimensions. The Planck length does not have any precise physical significance, and it is a common misconception that it is the inherent pixel size of the universe.