Why is Kryptonite so deadly to Superman?
The Green Kryptonite is the deadly one to Superman. it was introduces in the radio show in 1948 to give Superman a weakness that will make an interesting storyline. The fact that it came from Supes homeworld it emits radiation native to Krypton which causes Supes to loose his “godly” powers, and not being used to that he feels very very weak and helpless much like him being exposed to a red sun. but exposing green kryptonite to yellow sun intensifies it’s power a thousand times which it dangerous to Superman or any other Kryptonians on a yellow sun solar system.