Continuity mistake: When Clark is shot by the mugger, his hat falls down. In the next shot, while Lois is screaming, you can see him taking his hat off.
Revealing mistake: After Superman saves the cat, he takes off and wires holding him are visible.
Continuity mistake: When the council tells Jor-El not to worry them, a bald man standing in the back changes positions between shots.
Continuity mistake: The position of the baby when his mother holds him by the cradle differs in the wide and close shots.
Continuity mistake: After Clark runs by the train, a girl in a moving car stands up. In the next angle, a split second later, she is sitting down.
Other mistake: Clark does not have enough room beneath his clothes to have the suit, the cape and the boots.
Revealing mistake: Before the Hoover Dam breaks, the places where all the cracks and water will later appear are easily traced on the concrete, covered in plaster and painted. Either that, or the real Hoover Dam has burst many many times and always through the same spots.
Other mistake: Something that happens a lot in films. When Lex Luthor is watching the cops trail Otis the image on Lex's CCTV screen is actually just the scene from the film being played back. The shots change to angles where Lex couldn't possibly have a camera, for instance a close up on the cop holding his partner's hat. This mistake is especially more noticeable in the extended edition where Superman walks through Lex's 'gauntlet'.
Continuity mistake: Near the end of the movie when Superman pulls Lois Lane out of the car and she's already dead, she is very dirty all over because of all the dirt that "drowned" her. In the following shot when Superman is done crying over her and leaves her on the ground to reverse time so that she will come to life again, her clothes are all white and shiny.
Continuity mistake: When the lady of Lex Luthor is in a red dress pretending to be unconscious on the road we see her legs flat on the ground, then in the next shot one leg is standing up.
Answer: When Krypton exploded, the resulting debris was chemically altered through nuclear fusion, converting it into kryptonite. Bits traveled through space, some eventually ending up on Earth, where it is now lethal to anyone who was from that planet.
raywest ★
Pieces of Krypton that exploded in the Red Sun were made radioactive, and the Red Sun is one of the weaknesses of the Kryptonians.
I thought the Red Sun was poisonous to Kryptonians and caused the remnants of the planet Krypton to become radioactive and also absorb some of the solar energy from the Red Sun. I was under that impression, maybe I'm mistaken.