system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] Why is Superman so strong? Why Kryptonians? Why not other aliens? Humans don't become superpowered if they sunbathe in a different colored sun's radiation right?

and superman isn't just strong by earth standards, he's strong throughout the universe DC.  

so krypton was basically a planet of gods?

why'd they die then? wouldn't they take vacations to yellow stars to recherge/transform into super powered beings?
gpt
It has something to do with the radiation of their respective suns and Kryptonian physiology. A yellow sun will give a Kryptonian powers, while a red sun will not. There are other super-strong aliens though, Martians and Czarnians for instance (and they're just as extinct as the Kryptonians).

Krypton had colonies, but they were eventually abandoned because Kryptonian society had a massive superiority complex and was also isolationist. That way, nearly every Kryptonian died once the planet blew up.

There are descendants of one of Krypton's colonies called the Daxamites. They're basically the same. Look like humans, orbit a red sun, get superpowers under a yellow sun. They're also violently xenophobic and taught to attack any alien on sight, which explains why they remain among themselves.