I always try to assume that pretty much anything I think of has been thought of before, so I am relatively sure that this is also not a new question. we base our current measurement systems on arbitrary lengths such as the meter or foot, etc. there are certain applications where we use actual physical constants, but in general, all our measurements, since they are based on arbitrary items like the meter, are very awkward numbers with lots of decimal points - hard to remember and not reflective of the real constants of the universe. so, my question - has someone considered, or actually developed a system of measurement that is based on a true universal constant such as the speed of light - ie, where C=1 unit, or something similar? where can I read about this topic? thanks.