It varies depending on the story, but nearly always it either "just happens" (it's a natural disaster, sort of like an earthquake or a volcanic eruption but much more powerful) or it's a result of something the Kryptonians themselves are doing (this version became really common in the late 1960s, usually as an ecological cautionary tale).
Planet of Krypton
Krypton was a planet, but when it exploded, the debris drifted into space and it contained radiation.
Superman was from the planet Krypton, which exploded just after he was launched to safety in a rocket built by his father Jor-El.
Kr is the symbol fir Krypton which shares it's name with superman's birth planet.
Superman came from planet Krypton after it exploded on a rocket sent to Earth by his natural father Jor-El just before he was killed.Superman comes from the planet Krypton. He landed in Smallville, KS, where he was raised. He currently resides primarily from Metropolis. It is often depicted in the Northeast part of the US, but the exact state is rarely identified.
Planet of Krypton
Krypton was a planet, but when it exploded, the debris drifted into space and it contained radiation.
Krypton
Superman is from the planet Krypton. He is one of the last survivors from there since it exploded.
Superman was from the planet Krypton, which exploded just after he was launched to safety in a rocket built by his father Jor-El.
Kal-El--Superman's real name--was born on the planet Krypton. He was shot into space by his parents before the planet exploded. Thus, radioactive fragments of the plant Krypton are called "Kryptonite."
Supermans birthplace
Kr is the symbol fir Krypton which shares it's name with superman's birth planet.
Superman came from planet Krypton after it exploded on a rocket sent to Earth by his natural father Jor-El just before he was killed.Superman comes from the planet Krypton. He landed in Smallville, KS, where he was raised. He currently resides primarily from Metropolis. It is often depicted in the Northeast part of the US, but the exact state is rarely identified.
Krypton the fictional planet that Superman was born on exploded. Krypton [Kr] atomic number 36 on the periodic table is a non-exploding noble gas.
Kal-El on his home planet of Krypton. Clark Kent by his adoptive family.
lex luther