 In 1948, Krypton was ultimately destroyed when its red sun began to collapse; the planet was pulled into the sun and steadily crushed, then exploded in the ensuing supernova.When Krypton was destroyed, fragments from the planet were launched into space, resulting in the creation of a harmful radioactive substance known as kryptonite.Both Jor-El and Lara preserved some part of their "essence" (in the form of virtual copies of themselves) in the starship that took three years to bring their child to Earth.