Nice job making it all the way here. The Planck length is the distance light travels in a single unit of Planck time. A unit of Planck time is defined by the time it takes light to travel one Planck length. A bit circular logic by Planck. In any case, physicists say that anything smaller than a Planck length “makes no sense” with our existing models. In other words, until further notice, the Planck length is the Universe’s pixel size.
Keishinrei 