system
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human
[DC] Did the Kryptonians, as a culture, know exactly how their powers work? Does Superman know exactly how his powers work?

I've seen a lot of speculation on this sub, usually very well supported by canon sources, about how Superman's powers work. But often even the in-universe source is, itself, just speculation - like that one DC book with the segment containing Batman's ideas on how Kryptonian flight might work (I think I saw it linked in a comment here once, but I can't remember what it was called). Superman, and the source of his powers, seems to be a significant target of speculation within the DC universe.

Another thing I've gathered from this sub is how Krypton was a super advanced culture that was fully aware of how yellow sunlight gave them superpowers. So my question is this - did the Kryptonians of old fully understand the physics behind their superpowers, or was it a mystery to them to? Does Superman fully understand the physics behind what he does? And, if yes, was this something he worked out on his own, or was it something he learned from some lost relic of Kryptonian technology?
gpt
Yes. Keep in mind that there are many different canons (even if you just count comics alone) and even one canon may contradict itself depending on the author or story. 

Kryptonians travelled throughout the universe to multiple galaxies and found themselves super-powered by Yellow sunlight. They were conquerors on these worlds without even trying, and eventually they realized that they needed to retreat to their homeworld in order to keep themselves from subjugating the entire universe. 

How do their powers work? It's two-fold. One is that Krypton was originally one of the harshest, most inhospitable places for life to form. This means (in comic logic) that the humanoids who DO evolve are going to be super strong, super durable and super capable. In addition to that, their unique biology is a bit like plants and uses a type of photosynthesis, making them solar batteries. It just so happens that yellow sunlight is far far far better for them and overcharges them, granting them Superman-like powers. 

* It increases their natural strength, durability, and reflexes to obscene levels. 
* They can store this solar energy and release it through bursts from their eyes. 
* They can use a form of self-telekinesis to fly around.
* They can compress air in their super-strong lungs making it super-cold
* Their eyes become ultra-sensitive to more wavelengths in the electromagnetic spectrum, giving them what we'd call "X-Ray Vision."
* Their ears become hyper-sensitive and they can hear even the quietest sounds

But, this comes at a cost. If they're exposed to enough Red Sunlight, their physiology instantly shuts off these enhancements and brings them back down to base-level. When Krypton's sun went supernova, it irradiated the planet with red sunlight before it exploded, destroying it. Some of the Krypton-chunks made their way to Earth (likely via the same route that Superman's pod took) and they actually irradiate a metric TON of redsunlight. We call this Kryptonite, and it has the effect of Depowering Superman. Now like we already said, Superman has evolved on a planet much different from earth: higher gravity, denser atmosphere with a different composition. If you suddenly remove his super powers, he finds himself on an inhospitable alien world. It would be like pulling the space suit off a human on Mars. He finds himself weakened, gasping for breath, unable to function. 

These continuities establish that Superman was actually a *sickly* child, weak and unable to cope with this world, until he absorbed enough Yellow Sunlight and suddenly became an all-star athlete around High School.