Visible crew/equipment: Just after young Clark Kent jumps in front of the train, there is a close up of the train speeding by with a very visible camera in its reflection. (00:30:00)
Visible crew/equipment: While Lois chats with Clark and says "three kids, two cats" a microphone is reflected on a glass on the lower right corner. (01:03:50)
Visible crew/equipment: Near the beginning when Lois and Clark are walking out of the Daily Planet, Clark gets stuck in the revolving doors. But, look closely at the glass door, and you can see Richard Donner (confirmed in Superman expanded commentary) holding the door so that Christopher Reeve can get stuck.
Visible crew/equipment: During the first scene in the Daily Planet, after Lois exits Perry's office saying "You forgot my report", two big stage lights get reflected on the left glass door.
Visible crew/equipment: When the cocoon cradle crashes and the Kents pull-over, lights and bulky object (camera?) are reflected on the driver's door, perfectly visible when he opens the door. Seconds later, rigs and filming equipment are visible on the fender.
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.