Kara Zor-El (originally just "Kara"; Kryptonians during the Golden Era used a single name for most women, and a two-syllable name for men; thus the addition of the patronymic to the female name is a contemporary convention) is the last survivor of Argo City, which had survived the explosion of the planet Krypton and drifted through space. The city had been covered by a plastic dome for weather moderation, devised by Zor-El, the younger brother of Jor-El, a climatologist and engineer, the father of Superman (Kal-El). The dome held together a large chunk of land mass under the city as it drifted through space in the general direction of our Solar System. However, the bottom-most layers of bedrock were affected by the explosion of the great planet's fissionable core and underwent a slow but steady chain reaction, turning into green kryptonite. Using raw deposits and refined materials at hand, the residents of Argo City laid down a ground shield of lead foil to protect them from the developing kryptonite. Zor-El was also able to fashion a makeshift propulsion system to try to accelerate the city's approach to the Solar System. During the roughly 30 years Argo City traveled through space, Zor-El met and married Alura, daughter of In-Ze, who in turn bore their daughter, Kara—blond like her parents. But before the propulsion system was able to steer the city toward Earth, a deranged citizen named Jer-Em, who was suffering from survival guilt, damaged the exhaust, veering Argo toward a swarm of meteors that crashed into the underside of the land mass on which it rested. As the inhabitants of the colony were being slain by the green kryptonite radiation released by meteorites shredding the lead barrier, the adolescent Kara was sent to Earth by Zor-El in a rocket, to be raised by her cousin Kal-El (a.k.a. Clark Kent). To ensure she would be recognized by Superman, Kara's parents provided her with a uniform which was closely based on the one Superman wears.