"Faster than a speeding bullet, more powerful than a locomotive, able to leap tall buildings in a single bound" this was the famous quote from the George Reeves black and white show - and these were Superman's original powers as they were shown in the comics and in the first shows
These powers were down to gravity - just like John Carter
Similar to Spiderman's strength being proportional - a spider or an ant can lift 50 times it's body weight
It is never properly explained how Superman can fly - the yellow sun radiation being stored and used by him is what the later and modern writers rely on - but there is no "scientific" theory behind self powered flight
Of course lots of superheroes later have flight
In Man Of Steel Jor El explains about the earth's yellow sun being younger that Kryptons red sun and that his cells absorb the rays he also says "the gravity is lighter but the atmosphere is more nourishing" all these add up to the explanation - at least for this version
In the comics Krypton orbits a red sun while earth orbits a yellow sun
This has been carried over into the most recent movies
In Man Of Steel, Jor El says Earth's yellow sun is younger than Krypton's red sun
In 2025 Superman he uses the machine with yellow sun radiation to heal, and explains that Supergirl can't he drunk under the yellow sun so goes to a red sun planet
People write about "the sun is white and looks yellow due to the air, etc"
However, even if the early comic writers got the sun colour thing wrong, DC has decided to keep it to this day
So in the DC Universe - a FICTIONAL Universe, Earth has a yellow sun, and Krypton has a red sun
There are different coloured suns, same as there is different coloured Kryptonite, and they have different effects
