 Some works, such as Kevin J. Anderson's novel "The Last Days of Krypton", describe it as a few centuries ahead of Earth, while others, such as the "Superman" film series and "Man of Steel", describe it as thousands or even hundreds of thousands of years more advanced.In its first appearance, Krypton was only depicted at the moment of its destruction.Soon, beginning in the "Superman" comic strip, Krypton was shown to have been a planet similar to Earth, only older by eons and possessed of all the beneficial progress that implied (though the downside was the hint that Krypton exploded due mainly to old age).