The Basics
In its prime, Krypton was home to one of the most advanced civilizations in the DC Universe. Kryptonians look pretty much identical to humans, but they enjoyed technology and resources centuries ahead of anything humanity has to offer. Unfortunately, that technological superiority, combined with a growing sense of xenophobia, caused Krypton to shut itself off from the rest of the universe. And when respected scientist Jor-El found evidence that the planet was about to be completely destroyed, few of his fellow Kryptonians were willing to listen to his pleas. The planet died, taking the entire Kryptonian civilization with it. Only Superman and a handful of other survivors remain to carry the torch for this once-great civilization.Kryptonian Powers and Abilities
While Kryptonians appear identical to humans on the outside, their unique physiology gives them the potential to manifest incredible powers. Kryptonians are able to absorb and store solar radiation. Over time, this gives them superhuman strength, durability, flight and more unusual powers like heat vision and cold breath.The catch is that they need to absorb the energy of a healthy yellow sun. Because Krypton orbited a red sun, few of its inhabitants ever achieved their true superhuman potential. Also, sudden exposure to Krypton's environment (usually in the form of minerals called Kryptonite), can cause Kryptonian physiology to violently react. Depending on what form of Kryptonite they're exposed to, a Kryptonian may lose their powers or even be driven into an unstoppable rage.
But even without powers, Kryptonians have the benefit of highly advanced technology. They use crystals to store information in holographic form, and can even store a person's personality and memories in this way. They also have access to advanced cloning techniques, effectively making Kryptonians immortal as long as they can continue to harvest replacement organs from their clone bodies. Perhaps the most famous and feared Kryptonian invention is the Phantom Zone projector, a tool that opens a portal to a realm where time itself is frozen in place. The Phantom Zone is used as punishment only for Krypton's worst criminals.
Origin and Background
Along with Superman himself, the concept of Krypton was created by writer Jerry Siegel and artist Joe Shuster. The planet was first mentioned in 1938's Action Comics #1, though it didn't actually appear until the following year when Superman was given his own dedicated comic. Subsequent stories slowly began to flesh out this doomed planet and provided back-story for Superman's biological parents, Jor-El and Lara. The radio program The Adventures of Superman made its own significant contributions to Krypton's mythology, including debuting the concept of Kryptonite.While the basics of Superman's origin story and the death of Krypton have remained pretty consistent over the decades, many of the finer details have changed quite a bit. For instance, early stories depicted Krypton as a planet full of superhumans, whereas later stories changed this so that Kryptonians were powerless on their own world. Krypton was also once depicted as a world sharing Earth's orbit around the sun, not the remote planet it eventually became.
The exact reasons for Krypton's destruction also vary from telling to telling. In some cases the planet is destroyed because of its unstable sun. In others, it explodes due to a natural disaster or environmental devastation. In still others, the villain Brainiac causes Krypton's destruction after harvesting the city of Kandor for his personal collection.
Another major detail that's remained in flux concerns exactly how many Kryptonians survived the planet's destruction. Particularly in the '50s and '60's, comic book creators made a habit of introducing new Kryptonian refugees for Superman to meet, including his cousin, Supergirl, villains like General Zod and Jax-Ur (who survived because they were imprisoned in the Phantom Zone) and an entire menagerie of super-powered pets like Krypto the Super-Dog, Streaky the Super-Cat, Beppo the Super-Monkey and Comet the Super-Horse.DC eventually worked to simplify things by wiping these characters out of existence after 1985's Crisis on Infinite Earths and tasking writer/artist John Byrne with streamlining Superman's mythology. Thanks to Byrne's comic Man of Steel, Superman became the sole survivor of Krypton. However, that's again changed in more recent years, with new versions of Supergirl, Krypto and Zod being introduced. Recent stories have even revealed that Jor-El himself survived, apparently thanks to the intervention of Watchmen's Doctor Manhattan. And Krypton itself was briefly reborn in a crossover called "New Krypton," as Kandor was liberated from Brainiac's control and grew into its own planet.
