I remember in one Superman movie, it was explained why he became powerful. It was because of the energy from our star, the Sun, which was relatively younger than the star of Krypton. His genetics allowed him to absorb the energy from the sun and store it as latent energy. Once needed, he can release that stored energy which translates to his power.
I might be wrong, though.
Quite right! But that is for the modern superman which i will discuss on the next part. As stated above, this part discusses the early powers of superman where gravity alone was enough to explain such. Please keep posted for the second part of this post :)
I see! I will watch out for the second part, as requested. Haha