..but in its confined atomic state/structure, energy is paradoxically both inert and fluid, locked in a stable, devoted relationship with its parts; therefore, fluid energy emerges as mass --not to over simplify it all, but it's kinda like energy charged Gorilla Glue -- mass exists as solidified energy.When you get right down to the makeup of an atom it's quit amazing solid exists.
A tiny bit of energy orbiting something that isn't more than a ball of energy.
Take away all the space involved and you are not left with much.
Take away all the nothing between the tiniest things and you have nearly nothing.
A handful of electrons that themselves are probably filled with mostly nothing.
Hats of to the designer of that idea