Hey if anybody is interested, I made the following comment in a Superman thread on FARK. I decided I liked it and since I've been running a blog over here on Young Justice Wiki, I decided to copy it (Hey, Superman is a character on the show).
This is my SF explanation for Superman -- my closing line is "It's not canon, but it should be"
Dont' bother reading if you don't care.
The Kryptonians were created by the transcendent nanotech/picotech/femtotech/attotech alien intelligences that occupied Krypton's stellar system.
They created humans that duplicated Earth life as part of their consideration process about the next emerging intelligent species in the galaxy (humans from Earth). The humans of Krypton were integrated into such a portion of the common transcendent intelligence as they could understand.
The humans, like everything in the star system were constantly maintained at the sub-atomic level by the attotech tools that infused their physical forms -- changing or remaking their protons/molecules/etc. under the control of the transcendent mind.
The Kryptonian transcendent intelligence got caught in some incomprehensible development trap that destroyed it and thus the whole system.
Kal-El, as a child, did not have his mind fully integrated into the shared consciousness infrastructure of the system and could survive if he were removed, so his father sent him to Earth in a little starship before Krypton was destroyed.
His body (clothes and ship) all had the semi-intelligent attotech tools sustaining their physical form, but they were cut off from the larger controlling signals so they organized as local networks and defaulted to making Kal-El and the ship act like normal materials.
When they got near the G-class star with its different neutrino signature, the attotech got confused and simply began preserving Kal-El as a normal functioning human no matter what stresses or environmental conditions he encountered.
Material that was caught in the destruction of Krypton had its attotech tools malfunction and decay -- which caused the tools to send off confusing signals that disrupt any functioning attotech tools that get near them -- this material is called Kryptonite.
So, arriving on Earth, Kal-El found that his body was able to move without restriction. His arm (for example) could move freely with effort even if there was solid steel like a handcuff obstructing it. The steel would bend before its resistance could injure Kal-El's flesh.
With time, he learned tricks he could do with his physical form, like selectively refracting background neutrinos to transfer momentum to his physical form in a preferred direction. The semi-intelligent attotech monitored his conscious intentions and attempted to enable him to do what he wanted.
Similarly his conscious intention is able to control elements of his biological processes such as how long his hair grows on his head or face before the individual strand falls out (after which the attotech dissipates leaving normal hair protein).
And his conscious desire to appear different when he appears as Superman has allowed him to alter the dimensions of his facial features slightly so that Clark Kent's natural face bears no more than a minor resemblance to his creation Superman (and the attotech makes his fingerprints vary randomly as Superman because he wants them to).
Its not canon, but it should be.