Across all of Superman canon (comics, movies, TV series), explanations for both Superman's superhuman abilities and his vulnerability to kryptonite have been made multiple times. Are they always in agreement (i.e. our Sun's radiation) or have different writers gone different ways when it came to explaining the source of his strength, or the reason kryptonite robs him of his strength?

2 Answers 2


I can't cite chapter and verse, but back in the Silver Age some of his powers, notably strength, were attributed to the gravity differential between Earth and Krypton.

I found this by google searching but the site didn't say which issue it was.

Superman panel

  • Without citation this answer is very poor.
    – Valorum
    Commented Feb 18, 2018 at 0:18
  • 1
    I remember that Earth's lower gravity was used as an explanation for Superman's super strength. I remember thinking as a child that if the gravity difference was enough to explain he would probably be unable to breath Earth's much thinner atmosphere - he would be like an Earthman on the moon. Commented Feb 18, 2018 at 2:56
  • And where does Magic come in? :)
    – FuzzyBoots
    Commented Feb 18, 2018 at 4:01
  • Hey, who doesn't magic affect? Commented Feb 18, 2018 at 4:21

Short answer - no.

Longer answer - over the years, various creators have attempted to come up with more plausible reasons for Superman's powers. They have varied wildly in success.

In the Golden Age, at least one version of Superman's origin said that Kryptonians had at least some super-powers on Krypton. The Science Council scoffs at Jor-El's suggestion of migration to earth, citing that Earthlings are so simple and unadvanced, "They do not even possess X-Ray Vision!"

John Byrne posited the idea that many of Superman's powers were psionic in nature. He doesn't fly, he levitates; his strength has a facet of telekinesis to it, etc. During his run, Superman's invulnerability was due to a naturally generated force field that extended a fraction of an inch from his body. This field protected his suit (at the time it was not made of Kryptonian cloth) but not his cape, resulting in his capes being shredded all the time (and a truly hilarious scene where Ma Kent had made up a new batch of capes for her son, handing him a yard-high stack of red cloth.)

The most common thread between all the versions is a combination of Earth's lighter gravity and increased solar radiation combine to give Kryptonians (and Daxamites) their various powers. The gravity is generally seen as source of the strength and durability, and the solar radiation as the source of the more energy-based powers like heat vision.

  • As I recall, prior to the post-Crisis reboot be John Byrne in 1986, the comics didn't really have the idea of Superman as a "solar battery". Being under a red sun immediately reduced his abilities to those of a regular human, and being under a yellow sun again immediately restored those abilities, full force.
    – RDFozz
    Commented Jun 7, 2018 at 16:23
  • I've always thought the "force field" invulnerability thing was primarily to let Byrne use the visual of a tattered cape to indicate how tough a fight Superman had been in. Prior to his reboot, the cape was made of a Kryptonian fabric, and basically had its own "super-power" of being functionally infinitely elastic, so Superman could shove a mountain's worth of boulders into it, to carry them to another planet and the like.
    – RDFozz
    Commented Jun 7, 2018 at 16:25
  • @RDFozz Byrne took a lot of the facets of the origin away - some of the changes worked, some of them didn't. Keeping Ma and Pa Kent alive was a great move, and it's one of the few things that has lasted even through the movies. The elastic cape has made an appearance on Supergirl now - she's taught "Cape-fu" by Mon-El. Commented Jun 7, 2018 at 17:13
  • You're right about the red sun thing, and that's touched on in another question that bubbled to the top today. Long story short, the rules have changed as the desire to make it more plausible has increased. Needs of the story would probably cause changes as well. Commented Jun 7, 2018 at 17:15
  • The psionic/forcefield explanation also provided a way to explain how Superman could do things like lift massive objects that should fall apart or break if supported only by a single point, such as him lifting a ship or, as seen in Justice League, carrying an apartment building. He's not depending on simple physics in order to do it. Commented Jun 7, 2018 at 18:02

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