# Natural units - how and why

by arman.k.blog
Tags: natural, units
 P: 771 Its not that confusing.We're just saying that,our length scale is somehow that light travels one unit of it in one unit of our time. Or alternatively our time scale is somehow that light travels one unit of our length scale in that time and then say we don't care what are those time and length scales!!!Its the same about h. And about the formula E=m. Energy is not the same as mass here! Let's say the unit of time and length scales we chose are a and b.Then we have $E(kg a/b)=m(kg) c^2(a/b)$ its just we have c=1 in the unit a/b! and of course our unit of energy here becomes different from joule.We may also alter the unit of mass to an arbitrary one which again changes our unit of energy.