Since Time immemorial, man has sought to explain the powers of Kal- El, a.k.a. Superman. Siegel et al. Supposed that His mighty strength stems from His origin on another planet whose density and as a result, gravity, was much higher than our own. Natural selection on the planet of krypton would therefore endow Kal El with more efficient muscles and higher bone density; explaining, to first order, Superman's extraordinary powers. Though concise, this theory has proved inaccurate. It is now clear that Superman is actually flying rather than just jumping really high; and His freeze-breath, x-ray vision, and heat vision also have no account in Seigel's theory.
In this paper we propose a new unified theory for the source of Superman's powers; that is to say, all of Superman's extraordinary powers are manifestation of one supernatural ability, rather than a host. It is our opinion that all of Superman's recognized powers can be unified if His power is the ability to manipulate, from atomic to kilometer length scales, the inertia of His own and any matter with which He is in contact.
All the major hits are there: super strength, super speed, super senses, x-ray vision, freeze breath, heat vision, and even his ability to disguise himself as Clark Kent.
I wonder about two things. One is whether there is any way to incorporate his weakness of not being able to use super sight on lead into the theory, or whether that (as I suspect is the case) is just an arbitrary limitation of his power? The other thing is if I accept this unified theory, are there any other other powers that Superman should have at his disposal that we do not see him using all that much? For instance, it's been a while since physics, but Magneto's ability to manipulate magnetic fields should probably also allow him to induce or at least fiddle with electrical currents, right? But I feel like that's not something we see him do all that much. Are there analogous powers for Superman that are consistent with the unifying theory?
If you're interested about the physics of superheroes, you should definitely read (if you haven't already), the wonderful book by Professor James Kakalios, aptly titled The Physics of Superheroes. It's been years for me--I think I might reread!