>>111878611So Superman and Kryptonians by extent are basically a rip off of John Carter of Mars but in reverse. So if you take that into consideration and understand Superman is based on an 18th century understanding of science then yes it's been justified many times over.
Goku and the Saiyans are rip offs of Superman and Kryptonians and basically work the same way, or did at the beginning of DBZ with the secret of their power coming from their high gravity planet.
John Carter, coming from Earth which has a higher gravity than mars, allowed him to leap through the air with ease and have super strength and speed and whatnot, so basically that's the short version of why Superman is just an alien.
