If superman is of crypton why the cryptonita leaves it weak?

Answer 1

Actually, green Kryptonite makes him weak.

Red kyptonite kills him.

Yellow Kryptonite makes him stronger but nobody every gets that far into the comic books.

The answer is that the crystals of Kypton where forged from Krypton's red sun. They contain, absorb and release energy differently than do earth crystals.

Our Yellow sun hits the green crystals and drains Superman of his added powers. It hits the Red crystals and drains him of all his powers. It hits the yellow crystals and fills him with even more power.

If you think about it that is why the clear crystals are so important. They contain power and knowledge like a computer. The mistake in the first movie was a red and a green crystal were placed in the ship with Cal El. That would have killed him for sure.

Answer 2

Superman was born on Krypton (with a K).
When he was rocketed to Earth as a baby just before the planet exploded, the remains underwent a chemical reaction, becoming radioactive while changing their composition.
Coming into range of Kryptonite (with a K) starts to weaken Superman because Kryptonite radiation is on a frequency that is the exact opposite of what Krypton the planet was.
Thus, if it was a planet again, it can no longer support Kryptonian life. Ergo it is now deadly to Kryptonians.
The radiation itself is just as deadly as anything else radioactive and will affect a normal human with prolong exposure, just not as quickly as it does a Kryptonian.
The main types are GREEN: which will weaken and eventually kill a Kryptonian and RED which does not kill, but has a different affect on a Kryptonian with each exposure. The Smallville TV series limited RED K to just removing Clark's inhibitions, thus making him the "bad boy" of past episodes.
In the past there was also GOLD Kryptonite, which would remove super-powers permanently, but even if it still exists in the post-Crisis DC Universe, hasn't been seen in decades.
And an aside to LORD Z and the others, the crystals within the rocketship are safe since they left the planet with Kal-El BEFORE the explosion.

Answer 3

The hole idea is that in Crypton Superman is just a regular person.

Cryptonita kind of brings him back to his "humanized" form, but because this happens on Earth Cryptonita has an increased power over him.

Answer 4

he's not actually FROM crypton.. the sun If i remember right was the crypton...

So when the sun destroyed his planet it became like a evil to him

Answer 5

The kryptonite was altered and made radioactive when Krypton exploded. Also, the original kryptonite was deep underground on Krypton.

Answer 6

it only makes him weak if he is not on his planet

Answer 7

because of the radiation it has because of the explotion