As requested by SUPERBATSPIDERMAN, here is an editorial on Goku & Superman's similarities.
1) Origins: Goku is from planet Vegeta, sent to Earth just before Vegeta explodes. Once he lands on Earth, a humble old man (Grandpa Gohan) finds him & raises him into a very caring individual. Superman, similarly, is from the planet Krypton, sent to Earth just before Krypton explodes. Once he lands, an older couple, (also humble people), raise him into a very caring individual. Also, they were both sent to Earth in space pods (neat fact).
2) Biological Fathers: Both Goku & Superman's fathers were highly respected in their societies. The Saiyans(Goku's race)were a warrior race, with Bardock, Goku's father, being the strongest/best warrior of his time, (proven by him becoming the second known Super Saiyan and surpassing the sayain king's power level before Bardock reached his prime). The Kryptonians (Superman's race) were a scientific/technological race, Superman's father Jor-El was the top scientist of his time, shown by his various advances in technology & science with the Fortress of Solitude & his crystals being examples. So essentially, both biological fathers were at the "top" of their societies main profession.
3) Powers: Goku & Superman both have the following powers do to their alien origins...strength (incalculable limits), speed (both can move at supersonic speeds appearing as flicks in the air but Goku can teleport too), durability (extremely powerful force needed to hurt them), senses (better than top predator animals known, and longevity (stay in prime condition/appearance for hundreds of years), even being considered the most powerful non-magical beings of their respected universes. Abilities that they share also include flight (supersonic) & energy projection (ki blast/heat or x-ray vision).
4) Physiology affected by special radiation: Goku & all saiyans transform into giant monkey capable of incredible destruction whenever they are exposed to Green Spectrum radiation, usually in the form of Blutz Waves produced by a full moon, if the moon or his tail is destroyed or blocked/ cut off, he returns to normal. Superman infamously in the presence of Green Kryptonite radiation suffers intense pain until the Green Kryptonite is removed from his presence.
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5) Role Models: Goku & Superman are both continuously used as examples of good role models. The reason is because both have good values of caring for all people, family, friends, and second chances to those in need of it. Examples of the last point because it may be debatable is Goku giving chances of redemption to Piccolo & Vegeta or Superman giving Bizarro & Livewire chances of redemption.
6) Global: Both heroes are now usually not (at least anymore) restricted to saving one area but the whole world & many times the entire universe too. Great examples of this is their current rouges gallery, Goku has Frieza, Cell, Buu, Raditz, Omega Shenron, Cooler, Janemba, Andriods, Broly, Dr. Geru, Garlick jr., etc. which are all world-to-universe threats, usually the latter. Superman has Darkseid, Doomsday, Brainiac, Lex Luthor, Zod, Bizarro, Mister Mxyzptlk, etc. also usually world-to-universe threats, usually the latter.
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