52

52: The true significance of "52" is known to but a few. After the events of "Infinite Crisis", the remaining Earths created by Alexander Luthor collapsed back together, combining historical remnants to form one New Earth. However, the single universe was too small to contain the energy inside it and it began replicating - into 52 identical Universes, a new Multiverse. At the time of its re-creation, only the Monitors and the Guardians of the Universe were aware of the new Multiverse.

Shortly thereafter, Clark Kent, bereft of his Kryptonian abilities, retired his heroic alter ego, preferring instead to fight injustice from his position as an investigative journalist. To fill the void left in Metropolis, Booster Gold took it upon himself to become the city's new champion. With his robotic ally, Skeets, Booster Gold had access to historical documents from the 25th century. Using this information, he knew when and where certain disasters were scheduled to take place, and took measures to counter them. To his surprise however, the information that Skeets provided proved to be inaccurate. This resulted in several near-disasters, and it wasn't long before Booster Gold was looked upon as nothing more than a money-grubbing opportunist.

A short while later, Booster encountered the time traveling adventurer, Rip Hunter. Rip knew that Booster was important to the future of not only Earth, but the Multiverse as well. He informed Booster that Skeets' metal frame had been appropriated by a Venusian mind-worm known as Mister Mind. In order to prepare a strategy against him, they needed to come up with a plan to avoid Mister Mind's omnipresent scrutiny. To that end, Booster Gold faked his own death battling a creature known as a Ballostro. He left behind the physical remains of his own body from the future as evidence to throw off Mister Mind.

From there, Booster assumed a new identity – that of the hero, Supernova. Supernova continued to secretly work alongside Rip Hunter, amassing advanced technology from a variety of sources. They set up an ad-hoc base of operations at the Kryptonian bottle city of Kandor in Superman's Fortress of Solitude.

Mister Mind meanwhile, continued to evolve inside of Skeets' shell. After a fifty-two week gestation period, he emerged and revealed himself fully to Rip and Supernova. By this point, Booster returned to using the name Booster Gold, passing the identity of Supernova to his 21st century ancestor, Daniel Carter.

Mister Mind's new form required the energy of the Multiverse to sustain itself. He first invaded the dimensional realm known as the Phantom Zone, consuming its barriers (and thereby freeing dozens of Kryptonians). Afterwards, Mister Mind set out to find new realities with which to replenish himself.

During their efforts to stop the vastly powerful Mister Mind from destroying every universe, Hunter described Mind's efforts as "eating years and events from this universe's history -- altering the Earth with every flap of his wings". This resulted in the Earths changing, becoming different from New Earth in varying degrees.

Hunter's plan to defeat Mister Mind rested with Booster, Supernova, and Skeets. By fortifying Skeets' shell with Sivana's invention, Suspendium, they managed to imprison Mr. Mind in Skeets. Booster threw Skeets through an opening in time while Supernova ensured that it ended up in the correct time: Week 0 Day 0. Mister Mind's devolved form was found (again) by Doctor Sivana, who imprisoned him. Hunter used the 52 seconds of missing time to bind Mister Mind forever, condemned to live within that loop.