Deliberate mistake: Before the school bus crashes, a brown car is seen coming. When the angle changes we still see a brown car but it's a totally different model.
Deliberate mistake: Before Superman traps the black missile, its beam is really big and covers half of the lettering on the side. When Superman is behind, the fire is much smaller and the lettering is visible, allowing us to see Superman.
Deliberate mistake: At Lois' penthouse, before Superman says goodbye, the image is sharp and clear. Cuts to a close-up, and then check the next wide angle where he says goodnight and flies away: It's blurry and grainy because it's not live, but a screen with a previously shot scene to allow for the camera to turn left and, in a matter of seconds, no cuts at all, show Superman magically and quickly transformed into Clark Kent.
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.