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Krypton explained: Superman's home planet and lore
Krypton, Superman's home world, explained: why it exploded, the House of El, Jor-El and Lara, Kandor, the Phantom Zone, Argo City and the red sun Rao.
The short answer
Krypton was an advanced planet orbiting the red sun Rao. Its scientist Jor-El predicted the planet's destruction, and he and Lara sent their son Kal-El to Earth just before Krypton exploded. Survivors and relics include Supergirl, the bottled city of Kandor and the criminals of the Phantom Zone.
The planet
Krypton was a large, ancient planet with higher gravity than Earth, orbiting the red sun Rao, which Kryptonians also worshipped as a god (here’s what a red sun does to Superman). Its civilisation was technologically far ahead of ours but rigid and proud, and that pride is what doomed it.
The House of El
For every relative, see Superman’s full family tree.
- Jor-El: the scientist who discovered Krypton was going to explode. He was played by Marlon Brando (1978), Russell Crowe (2013) and Bradley Cooper (2025).
- Lara Lor-Van: Kal-El’s mother, played by Susannah York, Ayelet Zurer and Angela Sarafyan.
- Kal-El: their infant son, sent to Earth in a rocket. He grew up to be Superman.
- Zor-El and Alura: Jor-El’s brother and his wife, the parents of Kara Zor-El (Supergirl).
Pieces of Krypton that survived
- Kandor: a Kryptonian city shrunk and stolen by Brainiac, later kept in a bottle in the Fortress of Solitude (see Superman’s Kryptonian tech)
- Argo City: in many versions a fragment that survived for a time, where Kara grew up
- The Phantom Zone: a prison dimension holding Krypton’s worst criminals, including General Zod
- Kryptonite: radioactive fragments of the planet itself. See Superman’s weaknesses.
- The Fortress of Solitude: Superman’s Arctic retreat, built from Kryptonian crystal technology
Krypton on screen
The 1978 film’s crystal-white Krypton set the look for decades. Man of Steel (2013) showed a darker, organic world in its opening act, and the Syfy series Krypton (2018–2019) was a prequel set two generations before Kal-El. In the DCU, Superman’s parents’ message gets a surprising twist in Superman (2025).
Questions
Why did Krypton explode?
In most versions its unstable core reached a critical point. Jor-El warned the ruling council, but they refused to believe him.
What does 'Kal-El' mean?
In the comics Kal-El is simply Superman's Kryptonian birth name, with 'El' as the family or house name. Some modern stories translate it loosely as 'star child'.
Is Supergirl from Krypton?
Yes. Kara Zor-El is Superman's cousin. In many versions, including the DCU, she grew up on a fragment of Krypton called Argo City before coming to Earth.
Why do Kryptonians get powers on Earth?
Their cells absorb yellow-sun radiation. Krypton's sun, Rao, was red, so on Krypton they had no powers.